Fuel cell activation device and activation method based on hydrogen pump effect

Abstract

The present invention provides a fuel cell activation device and activation method based on the hydrogen pump effect, which belongs to the field of fuel cell technology and solves the problems of the prior art in that the active and passive discharge time, the anode pressure holding time are too long, and the activation effect is not ideal. The device includes a fuel cell to be activated, a hydrogen supply device, a hydrogen exhaust valve, a DC-DC converter, a current control unit, a pressure relief resistor and a short-circuit relay. The hydrogen side gas inlet of the fuel cell to be activated is connected to the hydrogen supply device, and the hydrogen side tail gas outlet is connected to the hydrogen exhaust valve, forming a gas circulation branch that self-starts after the fuel cell is purged. The power supply output end of the fuel cell to be activated is connected to the pressure relief resistor in sequence through the DC-DC converter and the current control unit to form a first discharge circuit, and its power supply output end is also connected to a short-circuit relay to form a second discharge circuit. The addition of a short-circuit relay to the device can achieve a short-circuit hydrogen pump activation effect, deplete the oxygen in the cathode cavity, and can also activate and re-wet the membrane electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a fuel cell activation device and activation method based on a hydrogen pump effect. Background Art

[0002] During the shutdown process of the fuel cell engine, pressure is released through active and passive discharge. After the pressure release is completed, the anode hydrogen will maintain the pressure for a period of time to ensure that the oxygen in the cathode cavity is completely consumed.

[0003] In the current fuel cell system shutdown strategy, a DC-DC load with a small current density (<0.2A / cm 2 ) Active discharge reduces the stack voltage to a safe voltage for the human body, consuming residual oxygen on the catalyst surface in the process. Then, passive discharge is used through a pressure relief resistor to reduce the stack voltage to 0V. After pressure relief is complete, the anode hydrogen maintains the pressure for a period of time to ensure that there is sufficient hydrogen to completely consume the oxygen in the cathode cavity.

[0004] The active and passive discharge times and anode pressure holding times of existing technologies are both too long, resulting in a long shutdown time. During the anode pressure holding process, the rate at which hydrogen diffuses through the proton exchange membrane to the cathode is slow, and extending the pressure holding time to ensure sufficient hydrogen to completely deplete the oxygen in the cathode cavity is not very effective. Secondly, after the shutdown purge is completed, the water distribution in the anode and cathode of the membrane electrode is in an unbalanced state, and the cathode catalyst layer is locally over-dried, which affects the service life of the fuel cell. Summary of the Invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a fuel cell activation device and activation method based on the hydrogen pump effect, so as to solve the problems of the prior art in that the active and passive discharge time, the anode pressure holding time are too long and the activation effect is not ideal.

[0006] On the one hand, an embodiment of the present invention provides a fuel cell activation device based on the hydrogen pump effect, comprising a fuel cell to be activated, a hydrogen supply device, a hydrogen exhaust valve, a DC-DC converter, a current control unit, a pressure relief resistor and a short-circuit relay; wherein,

[0007] The hydrogen side gas inlet of the fuel cell to be activated is connected to the output end of the hydrogen supply equipment, and its hydrogen side tail gas outlet is connected to the hydrogen exhaust valve, forming a gas circulation branch that automatically starts after the fuel cell is shut down and purged; the power supply output end of the fuel cell to be activated is connected to the pressure relief resistor in sequence through a DC-DC converter and a current control unit, forming the first discharge circuit of the fuel cell activation process, and the positive pole of its power supply output end is also connected to the negative pole of its power supply output end through a short-circuit relay, forming the second discharge circuit of the fuel cell activation process.

[0008] The beneficial effects of the above technical solution are as follows: by setting up the first discharge circuit and the second discharge circuit, the fuel cell system can realize the cathode hydrogen evolution reaction during the shutdown process. After the purge is completed during the shutdown process of the fuel cell to be activated, discharge can be carried out in sequence through the first discharge circuit and the second discharge circuit to achieve the hydrogen pump effect during the shutdown process, improve the fuel cell activation effect, and shorten the shutdown time. Among them, the first discharge circuit has two functions: active and passive discharge. During the active discharge process, the discharge effect is controlled by the current control unit and the pressure relief resistor. During the passive discharge process, the discharge is carried out through the pressure relief resistor. The second discharge circuit discharges through the short-circuit relay to achieve a short-circuit hydrogen pump activation effect. By combining active and passive discharge methods, the shutdown time is shortened. Through the first discharge circuit and the second discharge circuit, the hydrogen evolved from the cathode of the fuel cell to be activated can, on the one hand, consume the residual oxygen in the cathode cavity, thereby extending the storage time of the fuel cell to be activated, and at the same time, it can reduce platinum oxide during the cathode hydrogen pump process, thereby improving the catalytic activity of the fuel cell. In addition, during the short-circuit hydrogen pumping process, hydrogen protons carry water molecules from the anode to the cathode, alleviating the local over-drying of the cathode side of the membrane electrode caused by shutdown purge, and indirectly extending the service life and storage time of the fuel cell stack.

[0009] Based on the further improvement of the above device, the fuel cell activation device also includes:

[0010] The air inlet shut-off valve is located at the air side gas inlet of the fuel cell to be activated.

[0011] The air outflow cut-off valve is located at the air side exhaust outlet of the fuel cell to be activated.

[0012] Furthermore, the fuel cell activation device further comprises:

[0013] The controller is used to first close the air inlet shut-off valve and the air outlet shut-off valve, disconnect the short-circuit relay, and start the hydrogen exhaust valve and the current control unit after the fuel cell is shut down and purged, so as to load the fuel cell to be activated to a set current or a set current density through the DC-DC converter to perform active discharge through the first discharge circuit; and, when it is monitored that the total voltage of the fuel cell stack drops to a first set voltage value, turn off the current control function of the current control unit and perform passive discharge through the first discharge circuit; and, when it continues to monitor that the total voltage of the fuel cell stack drops to a second set voltage value, start the short-circuit relay to discharge through the second discharge circuit until the discharge is completed, thereby completing the activation of the fuel cell.

[0014] Furthermore, the controller further includes a data acquisition unit and a data processing and control unit connected in sequence; wherein the data acquisition unit further includes:

[0015] The voltage monitoring unit is connected to the power supply output terminal of the fuel cell to be activated through a DC-DC converter and is used to obtain the total voltage of the fuel cell stack in real time;

[0016] The current monitoring unit is connected to the positive or negative pole of the power supply output end of the fuel cell to be activated through a DC-DC converter, and is used to obtain the output current of the fuel cell stack in real time.

[0017] Furthermore, the current density is set to 0.5 A / cm 2 In the above, the first set voltage value is 30-40V, and the second set voltage value is 15-25V.

[0018] Furthermore, the data processing and control unit executes the following procedures to complete the fuel cell activation function:

[0019] After the fuel cell is shut down and purged, close the air inlet and outlet stop valves, and disconnect the short-circuit relay.

[0020] activating the hydrogen discharge valve and adjusting the control parameters of the current control unit to load the fuel cell to be activated to a set current density through the DC-DC converter, so as to perform active discharge through the first discharge circuit or an external electrical device;

[0021] Monitor the hydrogen flow rate entering the fuel cell to be activated and adjust the opening period of the hydrogen discharge valve so that the hydrogen flow rate entering the stack is consistent with the hydrogen flow rate when the fuel cell is normally operating at a set current density, until the stack output current reaches the set current density, and then end the adjustment of the opening period of the hydrogen discharge valve;

[0022] Monitor whether the total voltage of the fuel cell stack drops to 35V. If so, turn off the current control function of the current control unit and perform passive discharge through the first discharge circuit. Otherwise, continue to monitor the hydrogen flow rate into the fuel cell to be activated.

[0023] Monitor whether the total voltage of the battery stack drops to 20V. If so, start the short-circuit relay to discharge through the second discharge circuit. Otherwise, continue the passive discharge of the first discharge circuit.

[0024] Monitor whether the stack output current is zero. If so, discharge is terminated and the fuel cell activation device is turned off. Otherwise, continue to monitor the stack output current.

[0025] Furthermore, the fuel cell activation device further comprises:

[0026] A coolant temperature monitoring unit is provided at the coolant outlet of the fuel cell to be activated, with its output end connected to the input end of the controller;

[0027] The coolant heating device has an input end connected to the coolant outlet of the activated fuel cell, an output end connected to the coolant inlet of the activated fuel cell, and a control end connected to the output end of the controller.

[0028] Furthermore, the controller has a display module; wherein, the display screen of the display module displays real-time data of the voltage monitoring unit, the current monitoring unit, and the coolant temperature monitoring unit.

[0029] Furthermore, the current control unit further includes:

[0030] A hydrogen flow sensor is provided on the inner wall of the hydrogen-side gas inlet pipe of the fuel cell to be activated, and is used to obtain the hydrogen flow rate entering the fuel cell to be activated;

[0031] The hydrogen flow control subunit is used to obtain the stack output current and the hydrogen flow entering the stack in real time; and automatically adjust the hydrogen discharge valve opening period according to the stack output current and the hydrogen flow entering the stack to ensure that the hydrogen flow entering the stack during the activation process is consistent with the hydrogen flow when the fuel cell is operating normally at the set current density; and the input end of the hydrogen flow control unit is connected to the hydrogen flow sensor and the current monitoring unit, and its output end is connected to the control end of the hydrogen discharge valve.

[0032] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0033] 1. During the active discharge process, the cathode hydrogen pump is activated by cathode oxygen deficiency and DC-DC converter current loading.

[0034] 2. After the passive discharge is completed, the short-circuit hydrogen pump is activated by an external short-circuit relay.

[0035] 3. Through the above two hydrogen pump activation processes, the shutdown time is shortened and the residual oxygen in the cathode is consumed.

[0036] 4. By means of cathode hydrogen evolution, the oxide impurities on the membrane electrode are reduced to improve the catalytic activity.

[0037] 5. During the hydrogen pumping process, H+ carries water molecules through the membrane electrode, which is beneficial to the water balance inside the membrane electrode, alleviates the local over-drying phenomenon of the cathode catalyst layer caused by shutdown purge, and extends the service life of the fuel cell.

[0038] On the other hand, an embodiment of the present invention provides an activation method using the above-mentioned fuel cell activation device, comprising the following steps:

[0039] After the fuel cell to be activated has completed shutdown and purging, the air side gas flow of the fuel cell is closed and the short-circuit relay is disconnected;

[0040] activating the hydrogen discharge valve and the current control unit to load the fuel cell to be activated to a set current or a set current density through the DC-DC converter, so as to actively discharge the fuel cell to be activated through the first discharge circuit;

[0041] When it is detected that the total voltage of the fuel cell stack drops to a first set voltage value, the current control function of the current control unit is turned off to perform passive discharge on the fuel cell to be activated through the first discharge circuit;

[0042] When it is monitored that the total voltage of the fuel cell stack drops to a second set voltage value, the short-circuit relay is started to discharge through the second discharge circuit until the discharge is completed, thereby completing the activation of the fuel cell.

[0043] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0045] Figure 1 A schematic diagram of the fuel cell activation device based on the hydrogen pump effect in Example 1 is shown;

[0046] Figure 2 A schematic diagram of a short-circuit control circuit of a fuel cell activation device based on the hydrogen pump effect in Example 1 is shown.

[0047] Reference numerals:

[0048] 1- fuel cell to be activated; 2- DC-DC converter; 3- short-circuit relay;

[0049] 4- cathode; 5- anode. DETAILED DESCRIPTION

[0050] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0051] As used herein, the term "including" and its variations represent open inclusion, i.e., "including but not limited to." Unless otherwise stated, the term "or" means "and / or." The term "based on" means "based at least in part on." The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment." The term "another embodiment" means "at least one additional embodiment." The terms "first," "second," etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0052] Example 1

[0053] One embodiment of the present invention discloses a fuel cell activation device based on the hydrogen pump effect, such as Figures 1-2 As shown, it includes a fuel cell to be activated, a hydrogen supply device, a hydrogen exhaust valve, a DC-DC converter, a current control unit, a pressure relief resistor and a short-circuit relay.

[0054] The fuel cell to be activated includes a hydrogen channel and an air channel. One end of the hydrogen channel is a hydrogen-side gas inlet, and the other side is a hydrogen-side exhaust gas outlet. One end of the air channel is an air-side gas inlet, and the other side is an air-side exhaust gas outlet.

[0055] The hydrogen-side gas inlet of the fuel cell to be activated is connected to the output of the hydrogen supply equipment, and its hydrogen-side exhaust outlet is connected to the hydrogen exhaust valve, forming a gas circulation branch that automatically restarts after the fuel cell completes shutdown and purge. It should be noted that in the activation strategy, the air-side of the fuel cell to be activated is closed, consistent with existing technical solutions.

[0056] The power supply output end of the fuel cell to be activated is connected to the voltage relief resistor via a DC-DC converter and a current control unit in sequence, forming the first discharge circuit of the fuel cell activation process. The positive pole of the power supply output end is also connected to the negative pole of the power supply output end via a short-circuit relay, forming the second discharge circuit of the fuel cell activation process.

[0057] According to the above structure, the first discharge circuit has two functions: active discharge function and passive discharge function, and the switching between the two functions is achieved through the control of the current control unit.

[0058] Specifically, the current control unit is used to adjust the current between the positive and negative poles of the power supply output terminal of the fuel cell to be activated after startup, that is, to adjust the output current of the fuel cell stack to a set current or a set current density, thereby realizing the active discharge function of the first discharge circuit; and, when the current control unit is in the closed state, discharge is carried out through the pressure relief resistor to realize the passive discharge function of the first discharge circuit.

[0059] Alternatively, the current control unit may be an electronic load unit in addition to the structure described in Example 2. The electronic load unit can change the output current value or output current density according to a preset program or manual setting, as shown in the existing published patents CN200510031074.2 and CN202021239022.0.

[0060] The second discharge circuit can realize a short-circuit hydrogen pump effect, which is specifically achieved by closing the short-circuit relay.

[0061] Specifically, the short-circuit relay is used to activate the fuel cell to be activated by short-circuiting the hydrogen pump after closing.

[0062] During the active and passive discharge process, after the oxygen on the cathode catalyst surface is consumed, the following reactions occur at the anode and cathode respectively:

[0063] Anode: H2-2e - =2H +

[0064] Cathode: 2H + +2e - =H2,PtO2+4H + +4e-=Pt+2H2O

[0065] The hydrogen pump effect utilizes the cathode hydrogen evolution reaction to activate the fuel cell stack, which can be achieved by selecting any one of the following two different control processes: the first is to use a DC-DC converter to pull a large current to cause hydrogen to be deposited at the cathode (i.e., the active discharge process of the first discharge circuit); the second is to short-circuit the fuel cell stack through a short-circuit relay to generate a large current to cause a hydrogen evolution reaction at the cathode (i.e., the discharge process of the second discharge circuit).

[0066] A preferred embodiment is that after the activated fuel cell completes shutdown and purging, the above-mentioned gas circulation branch starts automatically, the hydrogen side continues to ventilate, and the air side is closed. At this time, there is still a lot of oxygen in the cathode (air side), and the first discharge circuit can be started for rapid discharge. In the active discharge stage, the oxygen in the cathode cavity diffuses to the catalyst surface at a slow rate, resulting in the cathode catalyst surface being in an oxygen-deficient state, so that the hydrogen evolution reaction begins to occur (hydrogen is pumped out at the cathode). After consuming part of the oxygen, the first discharge circuit can be switched from active discharge mode to passive discharge mode (passive discharge is achieved through a voltage relief resistor) to continue consuming oxygen; after consuming excess oxygen, the second discharge circuit can be started for rapid discharge, the short-circuit relay is started, and the cathode catalyst surface is always in an oxygen-deficient state, so the cathode will also undergo a hydrogen evolution reaction, and hydrogen is pumped out at the cathode.

[0067] After the second discharge circuit is turned on, the first discharge circuit is in a short-circuit state. Because there is a lot of oxygen in the cathode of the fuel cell to be activated, only the first discharge circuit is activated for discharge. After the excess oxygen is consumed by the cathode of the fuel cell to be activated, the second discharge circuit is activated for rapid discharge.

[0068] It should be noted that during the hydrogen pump effect process (i.e., the active discharge process of the first discharge circuit and the discharge process of the second discharge circuit), the hydrogen pressure and flow rate on the anode side must be ensured to prevent reverse polarity).

[0069] Compared with the prior art, the fuel cell activation device provided in this embodiment can realize the cathode hydrogen evolution reaction of the fuel cell system during the shutdown process by setting up the first discharge circuit and the second discharge circuit. After the purge is completed during the shutdown process of the fuel cell to be activated, discharge can be carried out in sequence through the first discharge circuit and the second discharge circuit to achieve the hydrogen pump effect during the shutdown process, improve the fuel cell activation effect, and shorten the shutdown time. Among them, the first discharge circuit has two functions: active and passive discharge. During the active discharge process, the discharge effect is controlled by the current control unit and the pressure relief resistor. During the passive discharge process, the discharge is carried out through the pressure relief resistor. The second discharge circuit discharges through the short-circuit relay to achieve a short-circuit hydrogen pump activation effect. By combining active and passive discharge methods, the shutdown time is shortened. Through the first discharge circuit and the second discharge circuit, the hydrogen evolved from the cathode of the fuel cell to be activated can consume the residual oxygen in the cathode cavity, extend the storage time of the fuel cell to be activated, and at the same time, platinum oxide can be reduced during the cathode hydrogen pump process, thereby improving the catalytic activity of the fuel cell. In addition, during the short-circuit hydrogen pumping process, hydrogen protons carry water molecules from the anode to the cathode, alleviating the local over-drying of the cathode side of the membrane electrode caused by shutdown purge, and indirectly extending the service life and storage time of the fuel cell stack.

[0070] Example 2

[0071] Based on the improvement of Example 1, the fuel cell activation device further includes an air inlet shut-off valve and an air outlet shut-off valve.

[0072] The air inlet shut-off valve is located at the air side gas inlet of the fuel cell to be activated and is used to control whether air is introduced.

[0073] The air outflow cut-off valve is located at the air-side tail gas outlet of the fuel cell to be activated and is used to control whether the air-side gas flows out.

[0074] Preferably, the fuel cell activation device further comprises a controller with a built-in fuel cell activation program.

[0075] The controller is used to close the air inlet shut-off valve and the air outlet shut-off valve, disconnect the short-circuit relay, and start the hydrogen exhaust valve and the current control unit after the fuel cell is shut down and purged, so as to load the fuel cell to be activated to a set current or a set current density through the first discharge circuit through the DC-DC converter; and, when the total voltage of the fuel cell stack (real-time data of the voltage monitoring unit) drops to the first set voltage value, turn off the current control function of the current control unit to passively discharge through the first discharge circuit, until the total voltage of the fuel cell stack drops to the second set voltage value, start the short-circuit relay to discharge through the second discharge circuit, until the discharge is completed, and complete the fuel cell activation (turn off the fuel cell activation device).

[0076] The input end of the controller is respectively connected to the output end of the voltage monitoring unit and the current monitoring unit, and the output end is respectively connected to the control end of the air inlet shut-off valve, the air outlet shut-off valve, the current control unit, the short-circuit relay, and the hydrogen discharge valve.

[0077] Preferably, the controller further comprises a data acquisition unit and a data processing and control unit which are connected in sequence.

[0078] Preferably, the data acquisition unit further includes a voltage monitoring unit, a current monitoring unit, and a hydrogen flow monitoring unit.

[0079] The voltage monitoring unit is connected to the power supply output terminal of the fuel cell to be activated through a DC-DC converter and is used to obtain the total voltage of the fuel cell stack in real time. Optionally, the voltage monitoring unit adopts an existing voltage sensor or other voltage monitoring equipment.

[0080] The current monitoring unit is connected to the positive or negative electrode of the power output terminal of the fuel cell to be activated through a DC-DC converter to obtain the stack output current in real time. Optionally, a current sensor is connected between the positive and negative electrodes of the power output terminal of the fuel cell to be activated.

[0081] The hydrogen flow monitoring unit is installed at the hydrogen side gas inlet of the fuel cell to be activated and is used to obtain the hydrogen flow entering the stack.

[0082] The data processing and control unit is used to close the air inlet shut-off valve and the air outlet shut-off valve, disconnect the short-circuit relay, and start the hydrogen exhaust valve and the current control unit after the fuel cell is shut down and purged, so as to load the fuel cell to be activated to the set current or set current density (real-time data of the current monitoring unit) through the DC-DC converter to actively discharge through the first discharge circuit; and, when the total voltage of the fuel cell stack (real-time data of the voltage monitoring unit) drops to the first set voltage value, turn off the current control function of the current control unit to passively discharge through the first discharge circuit, until the total voltage of the fuel cell stack (real-time data of the voltage monitoring unit) drops to the second set voltage value, start the short-circuit relay to discharge through the second discharge circuit, until the discharge is completed (the total voltage and total current of the fuel cell stack are both 0), and turn off the fuel cell activation device.

[0083] Preferably, the set current density is 0.5A / cm 2 The current density is 35V, and the second set voltage value is 20V.

[0084] The current density of the active discharge process is relatively low (about 0.2A / cm 2 ), in this embodiment, a large current is pulled by DC-DC, so that the current density is large during active discharge (reaching 0.5A / cm 2 ), which is more conducive to the occurrence of hydrogen pump effect.

[0085] Preferably, the data processing and control unit executes the following procedure to complete the fuel cell activation function:

[0086] S1. After the fuel cell is shut down and purged, close the air inlet and outlet shut-off valves and disconnect the short-circuit relay.

[0087] S2. Start the hydrogen discharge valve and adjust the control parameters of the current control unit to load the activated fuel cell to the set current density of 0.5A / cm through the DC-DC converter. 2 and actively discharges through the first discharge circuit or external electrical equipment;

[0088] S3. Monitor the hydrogen flow rate into the fuel cell to be activated and adjust the opening period of the hydrogen discharge valve so that the hydrogen flow rate into the stack is consistent with the hydrogen flow rate when the fuel cell is operating normally at the set current density until the stack output current reaches the set current density, ending the adjustment of the opening period of the hydrogen discharge valve;

[0089] S4. Monitor whether the total voltage of the fuel cell stack drops to 35V. If so, turn off the current control function of the current control unit and perform passive discharge through the first discharge circuit (pressure relief resistor). Otherwise, continue to monitor the hydrogen flow rate into the fuel cell to be activated;

[0090] S5. Monitor whether the total voltage of the stack drops to the set 20V. If so, activate the short-circuit relay to discharge through the second discharge circuit. Otherwise, continue the passive discharge of the first discharge circuit.

[0091] S6. Monitor whether the stack output current is zero. If so, discharge is terminated and the fuel cell activation device is turned off. Otherwise, continue to monitor the stack output current.

[0092] Preferably, the fuel cell activation device further comprises a coolant temperature control unit which integrates a coolant temperature monitoring unit and a coolant heating device.

[0093] The coolant temperature monitoring unit is located at the coolant outlet of the fuel cell to be activated. Its output is connected to the controller's input and is used to obtain real-time coolant inflow and send it to the controller. The coolant temperature monitoring unit can use a liquid temperature sensor.

[0094] The coolant heating device has an input terminal connected to the coolant outlet of the activated fuel cell, an output terminal connected to the coolant inlet of the activated fuel cell, and a control terminal connected to the output terminal of the controller. The device is used to increase the temperature of the activated fuel cell under the control of the controller. Preheating the coolant heating device accelerates the activation process of the fuel cell. The specific heating temperature can be determined through pre-calibration.

[0095] The coordinated use of the coolant temperature monitoring unit and the coolant heating device can accurately control the preheating temperature of the fuel cell to be activated.

[0096] Preferably, the controller further includes a display module. The display screen of the display module displays real-time data from the voltage monitoring unit, the current monitoring unit, and the coolant temperature monitoring unit. By observing the real-time data from the voltage monitoring unit and the current monitoring unit, the user can intuitively understand the progress of the activation process.

[0097] Preferably, the current control unit further includes a hydrogen flow sensor, a current monitoring unit, and a hydrogen flow control sub-unit.

[0098] The hydrogen flow sensor is arranged on the inner wall of the hydrogen-side gas inlet pipe of the fuel cell to be activated, and is used to obtain the hydrogen flow entering the fuel cell to be activated.

[0099] The current monitoring unit has been described above and will not be repeated here.

[0100] The hydrogen flow control subunit is used to obtain the stack output current and the hydrogen flow entering the stack in real time; and automatically adjust the hydrogen discharge valve opening period according to the stack output current and the hydrogen flow entering the stack to ensure that the hydrogen flow entering the stack during the activation process is consistent with the hydrogen flow when the fuel cell is operating normally at the set current density.

[0101] The input end of the hydrogen flow control unit is connected to the hydrogen flow sensor and the current monitoring unit, and the output end is connected to the control end of the hydrogen exhaust valve.

[0102] Optionally, the controller is a PLC controller, a single chip microcomputer or an industrial control board.

[0103] Preferably, the device further comprises a hydrogen circulation pump.

[0104] The hydrogen circulation pump's input end receives the hydrogen-side tail gas outlet of the activated fuel cell, and its output end receives the hydrogen-side gas inlet of the activated fuel cell. The hydrogen circulation pump is a component of the fuel cell system, used to circulate unreacted hydrogen from the anode.

[0105] During the active discharge phase, the DC-DC converter continuously draws current, and the slow diffusion of oxygen from the cathode cavity to the catalyst surface causes the cathode catalyst surface to be oxygen-deficient, leading to the onset of the hydrogen evolution reaction. During the discharge process of the second discharge loop, the current in the circuit remains between 150 and 200 A when the relay is short-circuited, and the cathode catalyst surface remains oxygen-deficient, causing the hydrogen evolution reaction to also occur at the cathode.

[0106] A preferred embodiment is: after the fuel cell system completes shutdown and purge and enters the active discharge state, the air inlet and outlet cut-off valves are closed, and the DC-DC converter is used to pull a load of 0.5A / cm 2 The current density is maintained until the total stack voltage drops to 35V. During this process, the hydrogen flow rate under these conditions must be kept consistent with the hydrogen flow rate during normal operation of the battery pack by controlling the opening cycle of the hydrogen discharge valve. The battery enters the passive discharge state, where the pressure is released through the pressure relief resistor until the stack voltage reaches 20V. The short-circuit relay is then activated, and the short-circuit hydrogen pump is activated. The hydrogen flow rate during this process remains consistent with that during active discharge.

[0107] Compared with the prior art, the fuel cell activation device based on the hydrogen pump effect of this embodiment has the following beneficial effects:

[0108] 1. During the active discharge process, the cathode hydrogen pump is activated by cathode oxygen deficiency and DC-DC converter current loading.

[0109] 2. After the passive discharge is completed, the short-circuit hydrogen pump is activated by an external short-circuit relay.

[0110] 3. Through the above two hydrogen pump activation processes, the shutdown time is shortened and the residual oxygen in the cathode is consumed.

[0111] 4. By means of cathode hydrogen evolution, the oxide impurities on the membrane electrode are reduced to improve the catalytic activity.

[0112] 5. During the hydrogen pumping process, H+ carries water molecules through the membrane electrode, which is beneficial to the water balance inside the membrane electrode, alleviates the local over-drying phenomenon of the cathode catalyst layer caused by shutdown purge, and extends the service life of the fuel cell.

[0113] Example 3

[0114] An embodiment of the present invention further provides a method for activating a fuel cell using the fuel cell activation device of embodiment 1 or 2, comprising the following steps:

[0115] S1 'after the fuel cell is activated and the shutdown purge is completed, the air side gas flow of the fuel cell is closed, and the short-circuit relay is disconnected;

[0116] S2 'start the hydrogen discharge valve, the current control unit, to be activated by the DC-DC converter to pull the fuel cell to a set current or set current density, to be activated through the first discharge circuit to be active discharge fuel cell;

[0117] S3 'monitors the total voltage of the stack drops to a first set voltage value, shuts down the current control function of the current control unit to passively discharge the fuel cell to be activated through the first discharge circuit;

[0118] S4'. When the total voltage of the stack is detected to drop to the second set voltage value, the short-circuit relay is activated to discharge through the second discharge circuit until the discharge is completed, the fuel cell activation is completed, and the fuel cell and its activation device are turned off.

[0119] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements over the prior art, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A fuel cell activation device based on hydrogen pump effect, characterized in that: It includes a fuel cell to be activated, a hydrogen supply device, a hydrogen exhaust valve, a DC-DC converter, a current control unit, a pressure relief resistor and a short-circuit relay; wherein, The hydrogen side gas inlet of the fuel cell to be activated is connected to the output end of the hydrogen supply equipment, and its hydrogen side tail gas outlet is connected to the hydrogen exhaust valve, forming a gas circulation branch that automatically starts after the fuel cell is shut down and purged; the power supply output end of the fuel cell to be activated is connected to the pressure relief resistor in sequence through a DC-DC converter and a current control unit, forming the first discharge circuit of the fuel cell activation process, and the positive pole of its power supply output end is also connected to the negative pole of its power supply output end through a short-circuit relay, forming the second discharge circuit of the fuel cell activation process.

2. The fuel cell activation device based on the hydrogen pump effect according to claim 1, characterized in that: Also includes: The air inlet shut-off valve is located at the air side gas inlet of the fuel cell to be activated; The air outflow cut-off valve is located at the air side exhaust outlet of the fuel cell to be activated.

3. The fuel cell activation device based on the hydrogen pump effect according to claim 2, characterized in that: Also includes: The controller is used to first close the air inlet shut-off valve and the air outlet shut-off valve, disconnect the short-circuit relay, and start the hydrogen exhaust valve and the current control unit after the fuel cell is shut down and purged, so as to load the fuel cell to be activated to a set current or a set current density through the DC-DC converter to perform active discharge through the first discharge circuit; and, when it is monitored that the total voltage of the fuel cell stack drops to a first set voltage value, turn off the current control function of the current control unit and perform passive discharge through the first discharge circuit; and, when it continues to monitor that the total voltage of the fuel cell stack drops to a second set voltage value, start the short-circuit relay to discharge through the second discharge circuit until the discharge is completed, thereby completing the activation of the fuel cell.

4. The fuel cell activation device based on the hydrogen pump effect according to claim 3, characterized in that: The controller further includes a data acquisition unit and a data processing and control unit connected in sequence; wherein the data acquisition unit further includes: The voltage monitoring unit is connected to the power supply output terminal of the fuel cell to be activated through a DC-DC converter and is used to obtain the total voltage of the fuel cell stack in real time; The current monitoring unit is connected to the positive or negative pole of the power supply output end of the fuel cell to be activated through a DC-DC converter, and is used to obtain the output current of the fuel cell stack in real time.

5. The fuel cell activation device based on the hydrogen pump effect according to claim 3 or 4, characterized in that: The set current density is 0.5A / cm 2 In the above, the first set voltage value is 30-40V, and the second set voltage value is 15-25V.

6. The fuel cell activation device based on the hydrogen pump effect according to claim 4, characterized in that: The data processing and control unit executes the following procedures to complete the fuel cell activation function: After the fuel cell is shut down and purged, close the air inlet and outlet stop valves, and disconnect the short-circuit relay. activating the hydrogen discharge valve and adjusting the control parameters of the current control unit to load the fuel cell to be activated to a set current density through the DC-DC converter, so as to perform active discharge through the first discharge circuit or an external electrical device; Monitor the hydrogen flow rate entering the fuel cell to be activated and adjust the opening period of the hydrogen discharge valve so that the hydrogen flow rate entering the stack is consistent with the hydrogen flow rate when the fuel cell is normally operating at a set current density, until the stack output current reaches the set current density, and then end the adjustment of the opening period of the hydrogen discharge valve; Monitor whether the total voltage of the fuel cell stack drops to 35V. If so, turn off the current control function of the current control unit and perform passive discharge through the first discharge circuit. Otherwise, continue to monitor the hydrogen flow rate into the fuel cell to be activated. Monitor whether the total voltage of the battery stack drops to 20V. If so, start the short-circuit relay to discharge through the second discharge circuit. Otherwise, continue the passive discharge of the first discharge circuit. Monitor whether the stack output current is zero. If so, discharge is terminated and the fuel cell activation device is turned off. Otherwise, continue to monitor the stack output current.

7. The fuel cell activation device based on the hydrogen pump effect according to any one of claims 3, 4, and 6, characterized in that: Also includes: A coolant temperature monitoring unit is provided at the coolant outlet of the fuel cell to be activated, with its output end connected to the input end of the controller; The coolant heating device has an input end connected to the coolant outlet of the activated fuel cell, an output end connected to the coolant inlet of the activated fuel cell, and a control end connected to the output end of the controller.

8. The fuel cell activation device based on the hydrogen pump effect according to claim 7, characterized in that: The controller has a display module; wherein, the display screen of the display module displays real-time data of the voltage monitoring unit, the current monitoring unit, and the coolant temperature monitoring unit.

9. The fuel cell activation device based on the hydrogen pump effect according to any one of claims 1, 2, 3, 4, 6, and 8, characterized in that: The current control unit further includes: A hydrogen flow sensor is provided on the inner wall of the hydrogen-side gas inlet pipe of the fuel cell to be activated, and is used to obtain the hydrogen flow rate entering the fuel cell to be activated; The hydrogen flow control subunit is used to obtain the stack output current and the hydrogen flow entering the stack in real time; and automatically adjust the hydrogen discharge valve opening period according to the stack output current and the hydrogen flow entering the stack to ensure that the hydrogen flow entering the stack during the activation process is consistent with the hydrogen flow when the fuel cell is operating normally at the set current density; and the input end of the hydrogen flow control unit is connected to the hydrogen flow sensor and the current monitoring unit, and its output end is connected to the control end of the hydrogen discharge valve.

10. An activation method using the fuel cell activation device according to any one of claims 1 to 9, characterized in that: The steps include: After the fuel cell to be activated has completed shutdown and purging, the air side gas flow of the fuel cell is closed and the short-circuit relay is disconnected; activating the hydrogen discharge valve and the current control unit to load the fuel cell to be activated to a set current or a set current density through the DC-DC converter, so as to actively discharge the fuel cell to be activated through the first discharge circuit; When it is detected that the total voltage of the fuel cell stack drops to a first set voltage value, the current control function of the current control unit is turned off to perform passive discharge on the fuel cell to be activated through the first discharge circuit; When it is monitored that the total voltage of the fuel cell stack drops to a second set voltage value, the short-circuit relay is started to discharge through the second discharge circuit until the discharge is completed, thereby completing the activation of the fuel cell.

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