Fuel cell online activation system, method and vehicle

Abstract

The present application provides an online activation system, method and vehicle for a fuel cell, and relates to the field of fuel cell technology. The system includes: a bidirectional DC converter, a fuel cell, and vehicle equipment, and the vehicle equipment includes: a power battery and electrical equipment on the vehicle; a hydrogen control valve is provided on the hydrogen intake pipe of the fuel cell, a hydrogen circulation pump and a hydrogen-water separator are provided on the hydrogen circulation pipe of the fuel cell, and the hydrogen circulation pipe is connected to the hydrogen intake pipe; an air control valve, an air compressor, an intercooler and a first humidifier are provided on the air intake pipe of the fuel cell, an air-water separator, a three-way valve and a second humidifier are provided on the air circulation pipe of the fuel cell, and the air circulation pipe is connected to the air intake pipe, and the connection position of the air circulation pipe and the air intake pipe is located between the air control valve and the air compressor. Through the system of the present application, the on-board fuel cell can be automatically activated by multi-cycle hydrogen pump and high-power activation when the whole vehicle is running.

Description

Technical Field

[0001] The present application relates to the field of fuel cell technology, and in particular to an online activation system, method and vehicle for a fuel cell. Background Art

[0002] During storage or operation, fuel cells usually experience slow oxidation or degradation of the fuel cell stack. This phenomenon can cause the performance of the fuel cell to drop significantly and the power generation efficiency to decrease after a period of operation or long-term storage. Therefore, the fuel cell needs to be reactivated to improve its performance.

[0003] In the prior art, for a vehicle-mounted fuel cell system, the fuel cell stack is usually disassembled after the vehicle has been running for a period of time, and activated using a dedicated fuel cell activation stand. Common activation methods include short-circuit activation, high-power activation, and hydrogen pump activation.

[0004] However, most of the existing fuel cell dedicated activation stands use a single activation method, which has the problems of long activation time and high hydrogen consumption. Summary of the invention

[0005] The present application provides an online activation system, method and vehicle for a fuel cell, which are used to automatically perform multi-cycle hydrogen pump activation and high-power activation on the on-board fuel cell when the entire vehicle is running, thereby reducing hydrogen consumption and improving the operating efficiency and service life of the fuel cell.

[0006] In a first aspect, the present application provides an online activation system for a fuel cell, the system comprising: a bidirectional DC converter, a fuel cell, and a vehicle device, the vehicle device comprising: a power battery and an electrical device on the vehicle, two first interfaces of the bidirectional DC converter are respectively connected to two ends of the vehicle device, and two second interfaces of the bidirectional DC converter are respectively connected to an anode and a cathode of the fuel cell;

[0007] A hydrogen control valve is provided on the hydrogen inlet pipe of the fuel cell, a hydrogen circulation pipe of the fuel cell is provided with a hydrogen circulation pump and a hydrogen-water separator, the hydrogen circulation pipe is connected with the hydrogen inlet pipe, and the connecting position of the hydrogen circulation pipe and the hydrogen inlet pipe is located between the hydrogen control valve and the fuel cell;

[0008] An air control valve, an air compressor, an intercooler and a first humidifier are arranged on the air intake pipe of the fuel cell, an air-water separator, a three-way valve and a second humidifier are arranged on the air circulation pipe of the fuel cell, the air circulation pipe is connected to the air intake pipe, and the connecting position of the air circulation pipe and the air intake pipe is located between the air control valve and the air compressor.

[0009] In a possible design, the bidirectional DC converter includes: a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch, a first resistor, a second resistor, a first capacitor, a second capacitor, a first high-voltage fuse, a second high-voltage fuse, a third high-voltage fuse and a fourth high-voltage fuse;

[0010] The first switch is respectively connected to the anode of the fuel cell, the high-voltage positive bus and the high-voltage negative bus of the bidirectional DC converter;

[0011] The second switch is respectively connected to the cathode of the fuel cell, the high-voltage positive bus and the high-voltage negative bus;

[0012] A first consumption circuit, a first EMC filter, a first capacitor, a step-up / step-down device, a second capacitor, and a second EMC filter are connected in sequence between the high-voltage positive bus and the high-voltage negative bus. A second consumption circuit is also arranged on the high-voltage positive bus. The second consumption circuit is located at an end of the high-voltage positive bus away from the fuel cell. The sixth switch is located at an end of the high-voltage negative bus away from the fuel cell. The first consumption circuit includes: a third switch and a first resistor connected in series. The second consumption circuit includes: a fourth switch, a fifth switch, and a second resistor. The fourth switch is arranged on the high-voltage positive bus. A path formed by the fifth switch and the second resistor being connected in series is connected in parallel to both ends of the fourth switch.

[0013] In a possible design, a plurality of load paths are further connected between the high-voltage positive bus and the high-voltage negative bus, and the plurality of load paths include at least one of the following paths: a path formed in series by a first high-voltage fuse and an air compressor, a path formed in series by a second high-voltage fuse and a cooling water pump, a path formed in series by a third high-voltage fuse and a hydrogen circulation pump, and a path formed in series by a fourth high-voltage fuse and a thermistor;

[0014] Both the hydrogen water separator and the air water separator are provided with drain valves;

[0015] The first humidifier and the second humidifier are the same humidifier.

[0016] In a second aspect, the present application provides an online activation method for a fuel cell, the method comprising:

[0017] The fuel cell is activated N times by an online activation system of the fuel cell, each activation cycle includes: hydrogen pump activation and high-power activation, and N is a positive integer greater than or equal to 1;

[0018] Hydrogen pump activation includes:

[0019] When the fuel cell is in a normal operation mode, adjusting the state of the fuel cell, and controlling the three-way valve to connect the second humidifier and the air-water separator;

[0020] Control the opening of the air control valve and the speed of the air compressor to maintain the gas pressure at the cathode of the fuel cell;

[0021] If the opening of the air control valve is less than or equal to the preset opening threshold, the air control valve is closed, and the hydrogen control valve, the drain valve of the hydrogen-water separator, and the drain valve of the air-water separator are controlled to maintain the gas pressure difference between the hydrogen side of the fuel cell and the air side of the fuel cell as the target pressure difference;

[0022] When the output current of the fuel cell is less than a first preset current threshold, the fuel cell is discharged at low power through the bidirectional DC converter;

[0023] When the output current of the fuel cell is less than a second preset current threshold, setting the fuel cell end of the bidirectional DC converter to an output current mode, and activating the fuel cell with a preset output current and a preset activation time;

[0024] High-power activation includes:

[0025] adjusting the working mode of the fuel cell to a normal operating mode through a bidirectional DC converter;

[0026] Control the three-way valve to connect the second humidifier and the air exhaust port of the three-way valve;

[0027] Increase the opening of the air control valve;

[0028] When the air control valve is fully opened, the fuel cell end of the bidirectional DC converter is set to an input current mode, and the fuel cell is activated with a target activation power and a target activation time.

[0029] In a possible design, the bidirectional DC converter includes: a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch, a first resistor, a second resistor, a first capacitor, a second capacitor, a first high-voltage fuse, a second high-voltage fuse, a third high-voltage fuse and a fourth high-voltage fuse;

[0030] The first switch is respectively connected to the anode of the fuel cell, the high-voltage positive bus and the high-voltage negative bus of the bidirectional DC converter;

[0031] The second switch is respectively connected to the cathode of the fuel cell, the high-voltage positive bus and the high-voltage negative bus;

[0032] A first consumption circuit, a first EMC filter, a first capacitor, a step-up / step-down device, a second capacitor, and a second EMC filter are sequentially connected between the high-voltage positive bus and the high-voltage negative bus. A second consumption circuit is also arranged on the high-voltage positive bus. The second consumption circuit is located at an end of the high-voltage positive bus away from the fuel cell. The sixth switch is located at an end of the high-voltage negative bus away from the fuel cell. The first consumption circuit includes: a third switch and a first resistor connected in series. The second consumption circuit includes: a fourth switch, a fifth switch, and a second resistor. The fourth switch is arranged on the high-voltage positive bus. A path formed by the fifth switch and the second resistor connected in series is connected in parallel to both ends of the fourth switch.

[0033] The normal operation mode of the fuel cell includes:

[0034] The first switch is connected to the high-voltage negative bus, the second switch is connected to the high-voltage positive bus, the fourth switch and the sixth switch are in a closed state, the third switch and the fifth switch are in an open state, the three-way valve is connected to the second humidifier and the air exhaust port, and the air control valve is in a fully open state;

[0035] Adjust the status of the fuel cell, including:

[0036] The gas pressure of the anode of the fuel cell is adjusted to a target anode pressure through a hydrogen control valve, and the gas pressure of the cathode of the fuel cell is adjusted to a target cathode pressure through an air compressor, a three-way valve and an air control valve, wherein the target anode pressure is greater than the target cathode pressure;

[0037] adjusting the humidity of hydrogen to the target humidity through the hydrogen circulation pump and the hydrogen-water separator, and adjusting the humidity of air to the target humidity through the first humidifier;

[0038] Low power discharge of the fuel cell via a bidirectional DC converter, including:

[0039] closing the third switch, and opening the third switch when the output current of the fuel cell drops to a second preset current threshold;

[0040] The fuel cell end of the bidirectional DC converter is set to an output current mode, and the fuel cell is activated with a preset output current and a preset activation time, including:

[0041] The first switch is controlled to be connected to the high-voltage positive bus, and the second switch is controlled to be connected to the high-voltage negative bus.

[0042] In a possible design, the fuel cell is activated N times through an online activation system of the fuel cell, including:

[0043] Collecting real-time status parameters of the fuel cell, the real-time status parameters including: shutdown storage time of the fuel cell, and operation time of the fuel cell in at least one power range;

[0044] The activation cycle of the fuel cell is calculated based on the real-time status parameters. The activation cycle is positively correlated with the downtime storage time and the operating time.

[0045] If the activation period is greater than or equal to the preset activation time threshold, the power battery state of the vehicle where the fuel cell is located is adjusted;

[0046] If the power battery state is the target battery state, the vehicle energy consumption is within the preset energy consumption range, and the operating time of the fuel cell reaches the preset operating time, the fuel cell is activated for N cycles through the fuel cell's online activation system, and the power battery state is the target battery state, including: the power battery power is within a first preset power range, the power battery temperature is within a first preset temperature range, and the power battery's continuous maximum charging power is greater than or equal to a first preset proportion of the rated power of the fuel cell.

[0047] In a possible design, the power battery state includes: power battery power, power battery temperature, and adjusting the power battery state of the vehicle where the fuel cell is located includes:

[0048] Adjusting the power battery power to an average power of a first minimum power and a first maximum power, where the first minimum power and the first maximum power are the minimum value and the maximum value of a first preset power range of the power battery before activation;

[0049] The power battery temperature is adjusted to an average temperature of a first minimum temperature and a first maximum temperature by the air conditioner of the power battery, and the first minimum temperature and the first maximum temperature are the minimum value and the maximum value of a first preset temperature range of the power battery before activation.

[0050] In one possible design, the method further includes:

[0051] During the N-cycle activation process, the real-time status of the power battery is collected in real time. The real-time status of the power battery includes: the real-time power of the power battery, the real-time temperature of the power battery, and the real-time maximum charging power of the power battery;

[0052] If the real-time power level of the power battery is not within the second preset power range, and / or the real-time temperature of the power battery is not within the second preset temperature range, and / or the real-time maximum charging power of the power battery is less than a second preset ratio of the rated power of the fuel cell, then exit the N-cycle activation.

[0053] In one possible design, activating a fuel cell at a target activation power and a target activation time includes:

[0054] If the target activation power is greater than the continuous rechargeable power of the power battery, and the target activation time corresponding to the target activation power is greater than the maximum charging time that the power battery can withstand, then the fuel cell is controlled to run at the target activation power for the maximum charging time, the fuel cell is controlled to idle for the maximum charging time, and then the fuel cell is controlled to run again at the target activation power for a first time, where the first time is the difference between the target activation time and the maximum charging time.

[0055] In a third aspect, the present application provides a vehicle, comprising an online activation system for a fuel cell according to the invention of the first aspect.

[0056] The present application provides an online activation system, method and vehicle for a fuel cell, the system comprising: a bidirectional direct current converter, a fuel cell and vehicle equipment, the vehicle equipment comprising: a power battery and electrical equipment on the vehicle, two first interfaces of the bidirectional direct current converter are respectively connected to two ends of the vehicle equipment, and two second interfaces of the bidirectional direct current converter are respectively connected to the anode and cathode of the fuel cell; a hydrogen control valve is provided on the hydrogen intake pipe of the fuel cell, a hydrogen circulation pipe of the fuel cell is provided with a hydrogen circulation pump and a hydrogen-water separator, the hydrogen circulation pipe is connected to the hydrogen intake pipe, and the connection position of the hydrogen circulation pipe and the hydrogen intake pipe is located between the hydrogen control valve and the fuel cell; an air control valve, an air compressor, an intercooler and a first humidifier are provided on the air intake pipe of the fuel cell, an air-water separator, a three-way valve and a second humidifier are provided on the air circulation pipe of the fuel cell, the air circulation pipe is connected to the air intake pipe, and the connection position of the air circulation pipe and the air intake pipe is located between the air control valve and the air compressor. The following technical effects are achieved: in order to ensure the activation effect of the fuel cell, the fuel cell is operated for a period of time before activation to increase the humidity inside the stack, thereby ensuring that the proton exchange membrane is in a moist state; when the fuel cell is activated by a hydrogen pump, the pressure on the hydrogen side of the fuel cell is maintained at the target anode pressure, and the pressure on the air side of the fuel cell is maintained at the target cathode pressure, so that a higher gas pressure and hydrogen flowing at the anode of the fuel cell can increase the speed of the hydrogen pump reaction and the effect of hydrogen pump activation, the flow of cathode air at the fuel cell and the shorter hydrogen pump activation in a single cycle avoid the accumulation of excessive hydrogen at the cathode of the fuel cell, thereby improving the safety of online activation of the fuel cell. Safety, avoiding the risk of explosion caused by a large amount of hydrogen accumulated at the cathode of the fuel cell; by adjusting the angle of the three-way valve, the air discharged from the air exhaust port of the three-way valve is gradually reduced, so that the air discharged from the fuel cell enters the air circulation pipe, and the air control valve is controlled to gradually reduce the amount of air provided to the online activation system of the fuel cell from the outside, thereby realizing the self-circulation of the cathode air of the fuel cell, so as to gradually reduce the oxygen content in the cathode of the fuel cell. At the same time, the external load of the fuel cell is replaced by a power battery that drives the electrochemical reaction inside the fuel cell. The power battery drives hydrogen ions from the anode to the cathode, and combines with electrons in the catalyst layer of the cathode to be converted into hydrogen and then precipitated.The precipitated hydrogen can improve the microstructure of the catalyst layer and the gas diffusion layer of the fuel cell, increase the porosity and tortuosity of the catalyst layer and the gas diffusion layer, increase the number of three-phase interfaces of reactants, catalysts and electrolytes, and restore the performance of the fuel cell. At the same time, the hydrogen precipitated at the cathode has a reducing property, which can reduce the oxides on the catalyst surface and clean the catalyst surface, increase the electrochemical active area of ​​the catalyst, and the reduced catalyst further improves the performance of the fuel cell. When the fuel cell is running at high power, the pressure and flow of the gas inside the fuel cell and the water generated by the reaction are relatively large, which can improve the microstructure of the gas diffusion layer and the catalyst layer, increase the transmission channels and reaction area of ​​gas, water and protons, and improve the performance of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0059] Figure 1 A schematic diagram of the structure of an online activation system for a fuel cell provided in an embodiment of the present application;

[0060] Figure 2 A schematic diagram of the structure of a bidirectional DC converter in an online activation system of a fuel cell provided in an embodiment of the present application;

[0061] Figure 3 A schematic diagram of a fuel cell online activation method provided in an embodiment of the present application Figure 1 .

[0062] Reference numerals:

[0063] 10-hydrogen control valve; 20-hydrogen circulation pump; 30-hydrogen water separator; 50-power battery; 60-bidirectional DC converter; 70-fuel cell; 80-first humidifier; 90-three-way valve; 100-air water separator; 130-air control valve; 140-air compressor; 150-intercooler; 301-drain valve; 710-hydrogen inlet pipe; 720-hydrogen circulation pipe; 730-air inlet pipe; 740-air circulation pipe; 750-air exhaust port; 701-anode of fuel cell; 702-cathode of fuel cell; 61 0-first consumption circuit; 620-first EMC filter; 630-boost / step-down converter; 640-second EMC filter; 650-second consumption circuit; 660-cooling water pump; 670-thermistor; K1-first switch; K2-second switch; K3-third switch; K4-fourth switch; K5-fifth switch; K6-sixth switch; R1-first resistor; R2-second resistor; C1-first capacitor; C2-second capacitor; F1-first high-voltage fuse; F2-second high-voltage fuse; F3-third high-voltage fuse; F4-fourth high-voltage fuse. DETAILED DESCRIPTION

[0064] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0065] In the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will appreciate that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit the difference. It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way. In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more.

[0066] It should be noted that the "at..." in the embodiments of the present application can be the instant when a certain situation occurs, or can be a period of time after a certain situation occurs, and the embodiments of the present application do not specifically limit this. In addition, the online activation system for a fuel cell provided in the embodiments of the present application is only used as an example, and the online activation system for a fuel cell can also include more or less content.

[0067] In order to clearly describe the technical solutions of the embodiments of the present application, some terms and technologies involved in the embodiments of the present application are briefly introduced below:

[0068] High Voltage Fuse: A high voltage fuse is one of the important components used to protect high voltage electrical equipment in power systems. They are mainly used to prevent damage to electrical equipment caused by overcurrent or short circuit. High voltage fuses protect high voltage electrical equipment by melting the internal fuse (usually made of metal wire or other fusible materials) under overcurrent conditions, thereby cutting off the circuit.

[0069] Bidirectional DC-DC Converter (BDC): can be used to transfer energy between power batteries and fuel cells. Depending on the activation requirements, the bidirectional DC converter can transfer the power battery's electrical energy to the fuel cell for activation, or transfer the fuel cell's electrical energy to the power battery.

[0070] EMC filter (Electromagnetic Compatibility Filter): also known as electromagnetic compatibility filter, is an electronic component used to suppress electromagnetic interference and ensure electromagnetic compatibility. It plays a key role in vehicle fuel cell systems and other electronic equipment, mainly used to reduce the impact of electromagnetic interference on the system and ensure that the equipment can work normally in a complex electromagnetic environment.

[0071] Buck-Boost Converter: Also known as a buck-boost converter, in fuel cell vehicles, the buck-boost converter can be used to adjust the voltage between the fuel cell and the power battery to ensure the efficiency and safety of energy transmission between the two.

[0072] In order to clearly understand the technical solution of the present application, the solution of the prior art is first introduced in detail.

[0073] In recent years, with the development of fuel cell technology and hydrogen production and storage technology, more and more new energy vehicles are equipped with fuel cell systems. As a power source, fuel cells face the problem of gradually declining performance after long-term operation or storage in vehicle applications, which is mainly manifested in the slow oxidation and degradation of the stack, resulting in reduced power generation efficiency. The fuel cell stack (fuel cell) is the place where the "hydrogen" fuel and oxygen in the air undergo electrochemical reactions, and is the most core component of the fuel cell system. The quality of its performance is the most critical factor affecting the power generation efficiency of fuel cells. After a fuel cell has been running for a long time or stored for a long time, its performance will show a significant decline. In order to restore and improve the performance of the fuel cell, it is particularly important to perform activation treatment regularly.

[0074] In traditional technologies, the activation process of vehicle fuel cell systems is usually cumbersome, requiring the fuel cell stack to be disassembled and transported to a special activation stand for processing when the vehicle is stopped. These stands mostly use a single activation method, such as short-circuit activation, high-power activation or hydrogen pump activation, which has the disadvantages of long activation cycle, high hydrogen consumption, complex operation and affecting the normal use of the vehicle.

[0075] Therefore, the existing activation method of vehicle-mounted fuel cells consumes a lot of resources and also affects the normal operation of the vehicle. Therefore, it is urgent to provide a low-cost and convenient method to activate vehicle-mounted fuel cells.

[0076] Based on this, in response to the above problems, the embodiments of the present application propose an online activation system, method and vehicle for a fuel cell, which can be used in the field of fuel cell technology, aiming to solve the above technical problems of the prior art, and is used to automatically complete the multi-cycle hydrogen pump activation and high-power activation process of the fuel cell during the operation of the vehicle, greatly improving the activation efficiency and convenience. During the normal operation of the vehicle, when the performance of the on-board fuel cell decays, there is no need to disassemble the fuel cell stack. Through the device integrated in the vehicle, the multi-cycle hydrogen pump activation and high-power activation are automatically performed to activate the fuel cell, thereby restoring the performance of the fuel cell. The entire activation process does not require human intervention and does not affect the operation of the entire vehicle. It should be noted that in a single cycle or multiple activation cycles, there is no fixed order of hydrogen pump activation and high-power activation. For convenience, the embodiments of the present application are schematically illustrated in the order of first performing hydrogen pump activation and then performing high-power activation.

[0077] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0078] Figure 1 This is a schematic diagram of the structure of an online activation system for a fuel cell provided in an embodiment of the present application. Figure 1 As shown, the online activation system of the fuel cell includes: a bidirectional DC converter 60, a fuel cell 70, and vehicle equipment. The vehicle equipment includes: a power battery 50 and electrical equipment on the vehicle. The two first interfaces of the bidirectional DC converter 60 are respectively connected to the two ends of the vehicle equipment, and the two second interfaces of the bidirectional DC converter 60 are respectively connected to the anode and cathode of the fuel cell 70.

[0079] A hydrogen control valve 10 is provided on the hydrogen inlet pipe 710 of the fuel cell 70, and a hydrogen circulation pump 20 and a hydrogen water separator 30 are provided on the hydrogen circulation pipe 720 of the fuel cell 70. The hydrogen circulation pump 20 can circulate the hydrogen in the hydrogen circulation pipe 720, thereby increasing the reaction rate inside the fuel cell 70 and taking out the water inside the fuel cell 70. The hydrogen water separator 30 is used to discharge the excess water in the hydrogen circulation pipe 720 to prevent the reaction rate of the fuel cell 70 from decreasing due to excessive water on the hydrogen side. The hydrogen circulation pipe 720 is connected to the hydrogen inlet pipe 710, and the connection position of the hydrogen circulation pipe 720 and the hydrogen inlet pipe 710 is located between the hydrogen control valve 10 and the fuel cell 70.

[0080] The air intake pipe 730 of the fuel cell 70 is provided with an air control valve 130, an air compressor 140, an intercooler 150 and a first humidifier 80, and the air circulation pipe 740 of the fuel cell 70 is provided with an air water separator 100, a three-way valve 90 and a second humidifier. The air water separator 100 is a water separator provided on the air side, and the air circulation pipe 740 is connected to the air intake pipe 730, and the connecting position of the air circulation pipe 740 and the air intake pipe 730 is located between the air control valve 130 and the air compressor 140.

[0081] In the embodiment of the present application, the online activation system of the fuel cell improves the DC converter in the traditional fuel cell system into a bidirectional DC converter, and both ends of the DC converter can be configured as voltage input, voltage output, current input, and current output modes. In other words, the bidirectional DC converter 60 has an input constant current mode, that is, the input current is constant; an input constant voltage mode, that is, the input voltage is constant; an output constant current mode, that is, the output current is constant; an output constant voltage mode, that is, the output voltage is constant; and a low-power discharge mode. It is used to transmit energy between the power battery 50 and the fuel cell 70, and the power energy of the power battery 50 can be transmitted to the fuel cell 70 for activation, or the power energy of the fuel cell 70 can be transmitted to the power battery 50, as well as electrical equipment such as motors and speakers on the vehicle.

[0082] The fuel cell 70 is a fuel cell stack including a plurality of single cells, wherein the plurality of single cells in the stack are in series mode; the hydrogen control valve 10 may be a proportional valve or a hydrogen injection valve arranged at the hydrogen inlet; the hydrogen-water separator 30 is a gas-water separator arranged on the hydrogen side of the fuel cell.

[0083] A three-way valve 90 is provided at the cathode air outlet of the fuel cell 70, and the two output ends of the three-way valve 90 are respectively connected to the air exhaust port 750 and the air circulation pipe 740. The air exhaust port 750 is used to discharge the air after the reaction through the fuel cell 70. The air circulation pipe 740 is connected to the air inlet of the air compressor 140. When the three-way valve 90 connects the cathode air outlet of the fuel cell 70 with the air circulation pipe 740, the air that has completed the reaction inside the fuel cell 70 can enter the fuel cell 70 again through the air inlet of the fuel cell 70 through the air circulation pipe 740 via the air compressor 140 to participate in the reaction. The flow rate of the recovered air in the air circulation pipe 740 can be adjusted by changing the opening of the three-way valve 90.

[0084] Furthermore, both the hydrogen water separator 30 and the air water separator 100 are provided with a drain valve 301. The air water separator 100 and the drain valve 301 are provided in the air circulation pipe 740, so that the water in the air in the air circulation pipe 740 can be separated and discharged. The hydrogen water separator 30 and the drain valve 301 are provided in the hydrogen circulation pipe 720, so that the water in the hydrogen in the hydrogen circulation pipe 720 can be separated and discharged.

[0085] The air control valve 130 may be a throttle valve of the air inlet, and is located at the front end of the cathode air inlet of the fuel cell 70. The air control valve 130 is arranged at the front end of the air inlet of the air compressor 140, and the amount of air entering the air compressor 140 from the atmosphere can be controlled by controlling the opening of the air control valve 130. By controlling the opening of the three-way valve 90 and the air control valve 130, the flow rate of the recovered air in the air circulation pipe 740 and the flow rate of the external air newly entering the fuel cell 70 can be adjusted.

[0086] The first humidifier 80 is an air self-humidifying humidifier; the air-water separator 100 is an air-water separator arranged on the air side of the fuel cell; and the second humidifier is also an air self-humidifying humidifier.

[0087] Furthermore, the first humidifier 80 and the second humidifier may be the same humidifier.

[0088] The specific structure of the bidirectional DC converter 60 in the online activation system of the fuel cell is described in detail below.

[0089] Figure 2 This is a schematic diagram of the structure of a bidirectional DC converter in an online activation system of a fuel cell provided in an embodiment of the present application. Figure 2As shown, in this embodiment Figure 1 Based on the embodiment, the specific structure of the bidirectional DC converter 60 is described in detail.

[0090] like Figure 2 As shown, the bidirectional DC converter 60 includes: a first switch K1, a second switch K2, a third switch K3, a fourth switch K4, a fifth switch K5 and a sixth switch K6, a first resistor R1, a second resistor R2, a first capacitor C1, a second capacitor C2, a first high-voltage fuse F1, a second high-voltage fuse F2, a third high-voltage fuse F3 and a fourth high-voltage fuse F4.

[0091] The first switch K1 is connected to the anode 701 of the fuel cell, the high-voltage positive bus and the high-voltage negative bus of the bidirectional DC converter 60 respectively.

[0092] The second switch K2 is connected to the cathode 702 of the fuel cell, the high-voltage positive bus and the high-voltage negative bus of the bidirectional DC converter 60 respectively.

[0093] A first consumption circuit 610, a first EMC filter 620, a first capacitor C1, a step-up / step-down device 630, a second capacitor C2, and a second EMC filter 640 are sequentially connected between the high-voltage positive bus and the high-voltage negative bus. A second consumption circuit 650 is also arranged on the high-voltage positive bus. The second consumption circuit 650 is located at an end of the high-voltage positive bus away from the fuel cell 70. The sixth switch K6 is located at an end of the high-voltage negative bus away from the fuel cell 70. The first consumption circuit 610 includes: a third switch K3 and a first resistor R1 connected in series. The second consumption circuit 650 includes: a fourth switch K4, a fifth switch K5, and a second resistor R2. The fourth switch K4 is arranged on the high-voltage positive bus. A path formed by the fifth switch K5 and the second resistor R2 connected in series is connected in parallel to both ends of the fourth switch K4.

[0094] Specifically, the first switch K1 may be a dual-control high-voltage switch, the second switch K2 may also be a dual-control high-voltage switch, the third switch K3 to the sixth switch K6 may all be high-voltage switches, the first resistor R1 may be a resistor for low-power discharge, and R2 may be a pre-charge resistor. After the anode high-voltage line of the fuel cell 70 is connected to the bidirectional DC converter 60, it can be connected to the high-voltage positive bus or high-voltage negative bus of the bidirectional DC converter 60 through the first switch K1 inside the bidirectional DC converter 60; similarly, after the cathode high-voltage line of the fuel cell 70 is connected to the bidirectional DC converter 60, it can be connected to the high-voltage positive bus or high-voltage negative bus of the bidirectional DC converter 60 through the second switch K2 inside the bidirectional DC converter 60. In addition, the bidirectional DC converter 60 also has a low-power discharge circuit (i.e., the first consumption circuit 610). When the fuel supply of the fuel cell 70 is small and the power generation is low, the electricity generated by the fuel cell 70 can be consumed through the first consumption circuit 610.

[0095] Furthermore, multiple load paths can be connected between the high-voltage positive bus and the high-voltage negative bus, and the multiple load paths include at least one of the following paths: a path formed by a first high-voltage fuse F1 and an air compressor 140 connected in series, a path formed by a second high-voltage fuse F2 and a cooling water pump 660 connected in series, a path formed by a third high-voltage fuse F3 and a hydrogen circulation pump 20 connected in series, and a path formed by a fourth high-voltage fuse F4 and a thermistor 670 connected in series.

[0096] The above detailed description of a fuel cell online activation system can be used to automatically perform multi-cycle hydrogen pump activation and high-power activation on the vehicle fuel cell when the vehicle is running. The following embodiment describes in detail how to use the system to activate the vehicle fuel cell.

[0097] In an embodiment of the present application, an executor of an online activation method for a fuel cell may be an electronic control unit (ECU) in a vehicle. This control unit may be a controller specially designed for fuel cell activation, or may be a part of the vehicle's existing power management system, such as a battery management system (BMS), a fuel cell control unit (FCCU), and a vehicle control unit (VCU), etc., without specific limitation.

[0098] Figure 3 A schematic diagram of a fuel cell online activation method provided in an embodiment of the present application Figure 1 . Combined Figure 1 and Figure 2 The method is applied to the online activation system of fuel cells. Figure 3 As shown, the method includes:

[0099] S101, collecting real-time status parameters of the fuel cell.

[0100] In the embodiment of the present application, the real-time status parameters include: the shutdown storage time of the fuel cell, and the operating time of the fuel cell in at least one power range.

[0101] Specifically, when the fuel cell is stored and operated, due to changes in its internal structure and oxidation of the catalyst in the catalytic layer, the performance of the fuel cell will deteriorate and the power generation efficiency will decrease, and the fuel cell needs to be reactivated to improve performance. In the embodiment of the present application, the performance of the fuel cell is restored by periodic activation. In order to calculate the activation cycle of the fuel cell, the downtime storage time of the fuel cell and the operating time of the fuel cell in multiple different power ranges must first be collected to calculate the activation cycle of the fuel cell based on these real-time state parameters of the fuel cell.

[0102] S102, calculating the activation period of the fuel cell according to the real-time state parameters.

[0103] In the embodiment of the present application, the activation period is positively correlated with the downtime storage time and the operation time. Specifically, the activation period is calculated as follows:

[0104]

[0105] Where T is the activation period, The downtime storage time of the fuel cell. The reactivation coefficient for shutdown storage is the preset value; to is the operating time of the fuel cell in different power ranges. n is the number of different power ranges, to is the reactivation coefficient corresponding to different power intervals, which is a preset value.

[0106] S103: If the activation period is greater than or equal to a preset activation time threshold, the power battery state of the vehicle where the fuel cell is located is adjusted.

[0107] In the embodiment of the present application, the power battery state includes: power battery power and power battery temperature. Adjusting the power battery state of the vehicle where the fuel cell is located includes:

[0108] Adjusting the power battery power to an average power of a first minimum power and a first maximum power, where the first minimum power and the first maximum power are the minimum value and the maximum value of a first preset power range of the power battery before activation;

[0109] The power battery temperature is adjusted to an average temperature of a first minimum temperature and a first maximum temperature by the air conditioner of the power battery, and the first minimum temperature and the first maximum temperature are the minimum value and the maximum value of a first preset temperature range of the power battery before activation.

[0110] Specifically, if the calculated activation cycle is greater than or equal to the preset activation time threshold, it can be determined that the fuel cell has met the time condition for activation. It can be further determined whether the historical number of activation cycles of the current fuel cell is less than the preset number of fuel cell activation cycles. If the historical number of cycles is less than the preset number of fuel cell activation cycles, the power battery state of the vehicle where the fuel cell is located can be further adjusted. That is, the power battery's charge and temperature are adjusted to maintain the power battery's charge and temperature in a suitable range, while ensuring the power consumption of the entire vehicle, and try to keep the power battery in a state with a large continuous charge and discharge power.

[0111] Specifically, in order to improve the success rate of fuel cell activation and prevent the vehicle from exiting the activation mode due to the power battery being too high or too low, or the power battery charging and discharging power being too low, the power battery's power and temperature can be adjusted to a suitable range before activation. First, the power battery is adjusted to the average power of the first minimum power and the first maximum power, and the power battery temperature is adjusted to the average temperature of the first minimum temperature and the first maximum temperature by controlling the power battery's air conditioner. Then, in order to ensure the activation effect of the fuel cell, the fuel cell can be operated for a period of time before activation to increase the humidity inside the stack, thereby ensuring that the proton exchange membrane is in a wet state.

[0112] S104: If the power battery state is the target battery state, the vehicle energy consumption is within a preset energy consumption range, and the operating time of the fuel cell reaches a preset operating time, the fuel cell is activated for N cycles through an online activation system of the fuel cell.

[0113] In the embodiment of the present application, the power battery state is a target battery state, including: the power battery power is within a first preset power range, the power battery temperature is within a first preset temperature range, and the continuous maximum charging power of the power battery is greater than or equal to a first preset ratio of the rated power of the fuel cell.

[0114] Specifically, the preset conditions for the fuel cell to perform N cycles of activation are: the power battery charge is between the first minimum charge and the first maximum charge, such as 40% ≤ power battery charge ≤ 60%; the power battery temperature is between the first minimum temperature and the first maximum temperature, such as 15 degrees Celsius ≤ power battery temperature ≤ 35 degrees Celsius; the continuous maximum charging power of the power battery is ≥ 75% × the rated power of the fuel cell, where 75% is the first preset ratio; the vehicle energy consumption is between the minimum and maximum values ​​of the vehicle energy consumption level; the fuel cell has been running for ≥ 15 minutes, where 15 minutes is the preset running time, and it can also be set to other values ​​according to the actual situation of the fuel cell, and there is no specific restriction here.

[0115] When the above conditions are met, the fuel cell can be activated cyclically. The fuel cell is activated N times by the online activation system of the fuel cell. Each activation cycle includes: hydrogen pump activation and high-power activation. N is a positive integer greater than or equal to 1.

[0116] The hydrogen pump activation includes: when the fuel cell is in a normal operation mode, adjusting the state of the fuel cell, and controlling the three-way valve to connect the second humidifier and the air-water separator;

[0117] Specifically, the fuel cell is in a normal operating mode including: the first switch is connected to the high-voltage negative bus, the second switch is connected to the high-voltage positive bus, the fourth switch and the sixth switch are in a closed state, the third switch and the fifth switch are in an open state, the three-way valve is connected to the second humidifier and the air exhaust port, and the air control valve is in a fully open state.

[0118] Adjusting the state of the fuel cell includes: adjusting the gas pressure of the anode of the fuel cell to the target anode pressure through the hydrogen control valve, and adjusting the gas pressure of the cathode of the fuel cell to the target cathode pressure through the air compressor, the three-way valve and the air control valve, the target anode pressure is greater than the target cathode pressure. Adjusting the hydrogen humidity to the target humidity through the hydrogen circulation pump and the hydrogen-water separator, and adjusting the air humidity to the target humidity through the first humidifier.

[0119] While adjusting the state of the fuel cell, the three-way valve is gradually controlled to connect the second humidifier and the air-water separator by adjusting the angle of the three-way valve.

[0120] That is to say, the fuel cell is in normal operation mode before the hydrogen pump is activated, and the end of the bidirectional DC converter 60 connected to the fuel cell 70 is set as the input end, current mode; the end of the bidirectional DC converter 60 connected to the vehicle and the power battery 50 is set as the output end, voltage mode. That is, the high-voltage positive bus is connected to the cathode 702 of the fuel cell, specifically the second switch K2 is connected to the high-voltage positive bus of the bidirectional DC converter 60; the high-voltage negative bus is connected to the anode of the fuel cell 70, specifically the first switch K1 is connected to the high-voltage negative bus of the bidirectional DC converter 60. The fourth switch K4 and the sixth switch K6 are in a closed state, and the third switch K3 and the fifth switch K5 are in an open state. The three-way valve 90 fully connects the cathode air outlet of the fuel cell 70 with the air exhaust port 750, and the air control valve 130 at the air inlet is also in a fully open state. At this time, the air entering the air compressor 140 is completely provided by the air inlet at the air control valve 130.

[0121] Then, preparations are made for activation of the fuel cell hydrogen pump. Specifically, the gas pressure of the anode 701 of the fuel cell is gradually adjusted to the target anode pressure (e.g., 1.7 Bar) through the hydrogen control valve 10, and the gas pressure of the cathode 702 of the fuel cell is gradually adjusted to the target cathode pressure (e.g., 1.5 Bar) through the air compressor 140, the three-way valve 90, and the air control valve 130, and the target anode pressure is greater than the target cathode pressure. The hydrogen humidity is adjusted to the target humidity (e.g., 100%) through the hydrogen circulation pump 20 and the hydrogen-water separator 30, and the air humidity is adjusted to the target humidity through the first humidifier 80.

[0122] While adjusting the state of the fuel cell, the angle of the three-way valve 90 is slowly adjusted to gradually control the three-way valve 90 to connect the second humidifier and the air-water separator 100, thereby reducing the air discharged from the air exhaust port 750, so that the air discharged from the fuel cell 70 is gradually transferred from the air exhaust port 750 to the air circulation pipe 740. The opening of the air control valve 130 and the speed of the air compressor 140 are controlled to maintain the gas pressure of the cathode 702 of the fuel cell as the target cathode pressure. In this process, the air entering the air compressor 140 from the air inlet side through the air control valve 130 will gradually decrease. When the three-way valve 90 completely connects the cathode air outlet of the fuel cell 70 with the air circulation pipe 740, the air discharged from the cathode air outlet of the fuel cell 70 will completely enter the air circulation pipe 740, and then be transported back to the inside of the fuel cell 70 through the air compressor 140 to participate in the reaction. In this process, the pressure of the anode 701 (hydrogen side) of the fuel cell is maintained as the target anode pressure, and the pressure of the cathode 702 (air side) of the fuel cell is maintained as the target cathode pressure. As the amount of circulating air in the air circulation pipe 740 increases and the oxygen in the air circulation pipe 740 is consumed, the gas that does not participate in the reaction of the fuel cell 70 in the air circulation pipe 740 will increase, the external air required to maintain the pressure of the cathode 702 of the fuel cell at the target cathode pressure will become less and less, and the opening of the air control valve 130 will become smaller and smaller.

[0123] If the opening of the air control valve 130 is less than or equal to the preset opening threshold (such as 2%), the air control valve 130 is closed so that all the air entering the air compressor 140 is the air in the air circulation pipe 740. The hydrogen control valve 10, the drain valve of the hydrogen water separator 30 and the drain valve of the air water separator 100 are controlled to maintain the gas pressure difference between the hydrogen side of the fuel cell 70 and the air side of the fuel cell 70 as the target pressure difference (such as 0.2 Bar). When the fuel cell 70 is activated by the hydrogen pump, the pressure on the hydrogen side of the fuel cell is maintained at the target anode pressure, and the pressure on the air side of the fuel cell is maintained at the target cathode pressure, so that the higher gas pressure and the hydrogen flowing at the anode of the fuel cell 70 can increase the speed of the hydrogen pump reaction and the effect of the hydrogen pump activation. The flow of the cathode air of the fuel cell 70 and the shorter hydrogen pump activation in a single cycle avoid the accumulation of excessive hydrogen at the cathode of the fuel cell, thereby improving the safety of the online activation of the fuel cell and avoiding the risk of explosion caused by the accumulation of a large amount of hydrogen at the cathode of the fuel cell.

[0124] Since the air control valve 130 is closed, there is no external air replenishment in the system. As the oxygen on the air side of the fuel cell 70 is consumed, less and less oxygen is available for the reaction inside the fuel cell 70, resulting in a smaller and smaller output current of the fuel cell 70.

[0125] When the output current of the fuel cell 70 is less than the first preset current threshold (e.g., 300 mA / cm2), the third switch K3 is closed to perform low-power discharge of the fuel cell 70 through the bidirectional DC converter 60. At this time, the oxygen remaining in the cathode 702 of the fuel cell reacts with the hydrogen in the anode 701 of the fuel cell to generate electricity that is consumed through the first resistor R1.

[0126] When the output current of the fuel cell 70 is less than the second preset current threshold (such as 50 mA / cm2), the third switch K3 is disconnected to stop consuming the electricity generated by the fuel cell 70 through the first resistor R1, that is, the low-power discharge mode of the bidirectional DC converter 60 is ended.

[0127] The first switch K1 is controlled to be connected to the high-voltage positive bus of the bidirectional DC converter 60, and the second switch K2 is controlled to be connected to the high-voltage negative bus of the bidirectional DC converter 60. That is, the end of the bidirectional DC converter 60 connected to the fuel cell 70 is set as the output end, current mode; the end of the bidirectional DC converter 60 connected to the vehicle and the power battery 50 is set as the input end, voltage mode. The fuel cell 70 is activated with a preset output current (such as 200 mA / cm2) and a preset activation time (such as 2 minutes). In this process, the power battery 50 provides electrical energy through the bidirectional DC converter 60 to drive the hydrogen pump activation reaction inside the fuel cell 70, promote the transmission and reaction of hydrogen, and thus realize the hydrogen pump activation of the fuel cell 70.

[0128] Normally, the principle of hydrogen pump activation is to introduce oxygen-free air into the cathode 702 of the fuel cell, that is, the gas introduced into the cathode does not participate in any electrochemical reaction inside the fuel cell stack. In the embodiment of the present application, by adjusting the angle of the three-way valve 90, the air discharged from the air exhaust port 750 of the three-way valve 90 is gradually reduced, so that the air discharged from the fuel cell enters the air circulation pipe 740, and the air control valve 130 is controlled to gradually reduce the amount of air provided to the online activation system of the fuel cell from the outside, thereby realizing the self-circulation of the cathode air of the fuel cell to gradually reduce the oxygen content of the cathode of the fuel cell. At the same time, the external load of the fuel cell 70 is replaced by the power battery 50 that drives the electrochemical reaction inside the fuel cell.

[0129] After hydrogen enters the fuel cell stack through the hydrogen inlet, it reaches the anode catalyst layer through the hydrogen flow channel in the bipolar plate and the loose and porous gas diffusion layer. Under the catalytic action of the catalyst in the catalyst layer, hydrogen loses electrons and becomes hydrogen ions. The hydrogen ions pass through the proton exchange membrane to reach the cathode, and the electrons reach the cathode electrode of the fuel cell under the drive of the power battery 50, and combine with the hydrogen ions in the cathode to generate hydrogen. In this process, the power battery 50 drives the hydrogen ions from the anode of the fuel cell to the cathode of the fuel cell, and combines with the electrons in the catalyst layer of the cathode, and then precipitates after being transformed into hydrogen again. The precipitated hydrogen can improve the microstructure of the catalyst layer and the gas diffusion layer of the fuel cell, improve the porosity and tortuosity of the catalyst layer and the gas diffusion layer, increase the number of three-phase interfaces of the reactant, catalyst and electrolyte, and restore the performance of the fuel cell. At the same time, the hydrogen precipitated from the cathode has a reducing property, which can reduce the oxide on the catalyst surface and clean the catalyst surface, increase the electrochemical active area of ​​the catalyst, and the reduced catalyst further improves the performance of the fuel cell. Therefore, hydrogen pump activation can increase the number of three-phase interfaces between reactants, catalysts and electrolytes, improve the transmission capacity of oxygen, hydrogen, water and protons, and improve the performance of fuel cells. Among them, the three-phase interface refers to the contact surface between gas (such as oxygen or hydrogen), catalyst (usually precious metals such as platinum) and electrolyte (proton exchange membrane). This interface is the place where electrochemical reactions occur in fuel cells. Through hydrogen pump activation, impurities or by-products that block or hinder the transmission of reactants can be removed, thereby enhancing gas diffusion and proton conduction and improving the efficiency of electrochemical reactions. The activation process helps to restore or enhance catalyst activity, reduce internal resistance, and increase current and voltage output, thereby improving the overall performance of fuel cells.

[0130] With the increase of fuel cell power and the decrease of fuel cell cost, in order to improve the power generation efficiency of the whole vehicle and reduce the hydrogen consumption of the whole vehicle, the rated power of the fuel cell carried by the whole vehicle is getting larger and larger. When the whole vehicle is actually running, the fuel cell usually operates in the range with higher power generation efficiency, and rarely operates at high power and rated power. That is, the operating power of the fuel cell is usually set in the power range with higher power generation efficiency of the fuel cell, that is, below 70% of the rated power of the fuel cell. When the average power demand of the whole vehicle is low, the fuel cell may even run below 50% of the rated power for a long time. Therefore, after the fuel cell has been running for a long time, high-power activation can effectively improve the power generation efficiency of the fuel cell.

[0131] When the fuel cell is running at high power, the pressure and flow of the gas inside the fuel cell and the water produced by the reaction are relatively large, which can "open" the closed and semi-closed holes in the gas diffusion layer and the catalyst layer, further improving the microstructure of the gas diffusion layer and the catalyst layer. At the same time, high-pressure and large-flow gas and water can more effectively "flush out" impurities in the gas diffusion layer and the catalyst layer, further increasing the transmission channels and reaction areas of gas, water and protons, and improving the performance of the fuel cell.

[0132] However, due to the limited layout space and design cost of the vehicle, vehicles equipped with fuel cells are usually equipped with smaller power batteries. When the fuel cell is running at high power, it may exceed the continuous rechargeable power of the power battery. Therefore, when performing high-power activation of the fuel cell, the charging capacity of the power battery needs to be considered.

[0133] After a single hydrogen pump activation is completed, high-power activation of the fuel cell can be performed.

[0134] High-power activation includes: adjusting the working mode of the fuel cell 70 to the normal operating mode through the bidirectional DC converter 60. Specifically, the first switch K1 is controlled to be connected to the high-voltage negative bus of the bidirectional DC converter 60, and the second switch K2 is controlled to be connected to the high-voltage positive bus of the bidirectional DC converter 60. That is, the end of the bidirectional DC converter 60 connected to the fuel cell 70 is set as the input end, voltage mode; the end of the bidirectional DC converter 60 connected to the vehicle and the power battery 50 is set as the output end, voltage mode. And keep the voltage of the single cell in the fuel cell 70 at a preset voltage (such as 0.6 volts). In addition, setting the end of the bidirectional DC converter 60 connected to the fuel cell 70 as the input end, voltage mode, can prevent the fuel cell 70 from being damaged by the "reverse polarity" phenomenon of the fuel cell monomer due to lack of oxygen.

[0135] During the hydrogen pump activation process, the cathode 702 of the fuel cell does not contain oxygen, and the air pressure is high, and the gas volume is large, which can dilute the hydrogen precipitated from the cathode. At this time, the air in the atmosphere can be slowly introduced, and the cathode can be purged while the cathode air supply is restored to avoid the explosion of hydrogen mixed with oxygen in the air. Specifically, the three-way valve 90 is controlled to connect the second humidifier and the air exhaust port 750 of the three-way valve 90, and the opening of the air control valve 130 is gradually increased. When the air control valve 130 is fully opened, the fuel cell end of the bidirectional DC converter 60 is set to the input current mode, and the fuel cell is activated with the target activation power and the target activation time. That is, the opening of the three-way valve 90 is slowly adjusted to reduce the air circulating in the air circulation pipe 740, so as to gradually reduce the internal circulation of the air, and the opening of the air control valve 130 is slowly increased to increase the entry of external air. When the air control valve 130 is fully opened, the fuel cell end of the bidirectional DC converter 60 is set to the input end, the current mode, and the normal operation of the fuel cell 70 is restored, thereby entering the high-power activation process of the fuel cell. Specifically, the fuel cell 70 is controlled to operate with the target activation power and the corresponding target activation time in the target power activation array, thereby achieving high-power activation of the fuel cell 70. The target activation power and the corresponding target activation time in the target power activation array are preset values.

[0136] Table 1 Comparison table of target activation power and corresponding target activation time

[0137]

[0138] Table 1 shows each target activation power and the corresponding target activation time in the target power activation array. Wherein, i is the number of each target activation power. Specifically, in a possible implementation, as shown in Table 1, the fuel cell 70 can be controlled to start from the target activation power P (1) corresponding to number 1, and the corresponding target activation time T (1), and in the order of numbers, run the corresponding target activation time at each target activation power in sequence, until the last target activation power P (12) corresponding to number 12 and the corresponding target activation time T (12) are run, so as to complete a high-power activation.

[0139] Furthermore, if the target activation power P(i) is greater than the continuous rechargeable power of the power battery 50, and the target activation time T(i) corresponding to the target activation power P(i) is greater than the maximum charging time t1 that the power battery can withstand, then after controlling the fuel cell 70 to run at the target activation power P(i) for the maximum charging time t1, the fuel cell 70 can be controlled to idle for the maximum charging time t1, and then the fuel cell 70 is controlled to continue to run at the target activation power P(i) for the first time t2, and the first time t2 is the difference between the target activation time T(i) and the maximum charging time t1, so that the total time the fuel cell 70 runs at the target activation power P(i) is the corresponding target activation time T(i).

[0140] S105. During the N activation cycles, the real-time status of the power battery is collected in real time.

[0141] In the embodiment of the present application, the real-time status of the power battery includes: the real-time power of the power battery, the real-time temperature of the power battery, and the real-time maximum charging power of the power battery;

[0142] Specifically, during the activation of the fuel cell, the status of the entire vehicle can also be monitored, including the real-time power level of the power battery, the real-time temperature of the power battery, and the real-time maximum charging power of the power battery.

[0143] S106. If the real-time power level of the power battery is not within the second preset power range, and / or the real-time temperature of the power battery is not within the second preset temperature range, and / or the real-time maximum charging power of the power battery is less than a second preset ratio of the rated power of the fuel cell, then exit the N-cycle activation.

[0144] In the embodiment of the present application, the second preset power range can be: 30% ≤ power battery power ≤ 80%. The second preset temperature range can be: 10 degrees Celsius ≤ power battery temperature ≤ 50 degrees Celsius. The second preset ratio can be 60%, that is, when the continuous maximum charging power of the power battery is less than 60% × the rated power of the fuel cell, the fuel cell can exit the N-cycle activation mode and operate in the normal power generation mode.

[0145] Furthermore, each time a pair of fuel cells completes a complete hydrogen pump activation and high-power activation, the number of historical activation cycles of the fuel cell is increased by 1. If the number of historical activation cycles of the fuel cell is less than the preset number of fuel cell activation cycles, the fuel cell can be activated for the next round of hydrogen pump activation and high-power activation; if the number of historical activation cycles of the fuel cell is greater than or equal to the preset number of fuel cell activation cycles, the activation cycle of the fuel cell and the number of historical activation cycles of the fuel cell can be set to 0, and the activation of the fuel cell can be completed, so that the fuel cell operates in the normal power generation mode.

[0146] The present embodiment provides an online activation method for a fuel cell, which is applied to an online activation system for a fuel cell. In order to ensure the activation effect of the fuel cell, the fuel cell is operated for a period of time before activation to increase the humidity inside the stack, thereby ensuring that the proton exchange membrane is in a moist state; when the fuel cell is activated by a hydrogen pump, the pressure on the hydrogen side of the fuel cell is maintained at the target anode pressure, and the pressure on the air side of the fuel cell is maintained at the target cathode pressure, so that a higher gas pressure and hydrogen flowing at the anode of the fuel cell can increase the speed of the hydrogen pump reaction and the effect of hydrogen pump activation. The flow of air at the cathode of the fuel cell and the shorter hydrogen pump activation in a single cycle avoid the accumulation of excessive hydrogen at the cathode of the fuel cell, thereby improving the safety of online activation of the fuel cell and avoiding The risk of explosion caused by a large amount of hydrogen accumulated at the cathode of the fuel cell is eliminated; by adjusting the angle of the three-way valve, the air discharged from the air exhaust port of the three-way valve is gradually reduced, so that the air discharged from the fuel cell enters the air circulation pipe, and the air control valve is controlled to gradually reduce the amount of air provided to the online activation system of the fuel cell from the outside, thereby realizing the self-circulation of the cathode air of the fuel cell, so as to gradually reduce the oxygen content in the cathode of the fuel cell. At the same time, the external load of the fuel cell is replaced by a power battery that drives the electrochemical reaction inside the fuel cell. The power battery drives hydrogen ions from the anode to the cathode, and combines with electrons in the catalyst layer of the cathode to be converted into hydrogen and then precipitated. The precipitated hydrogen can improve the microstructure of the catalyst layer and the gas diffusion layer of the fuel cell, increase the porosity and tortuosity of the catalyst layer and the gas diffusion layer, increase the number of three-phase interfaces of reactants, catalysts and electrolytes, and restore the performance of the fuel cell. At the same time, the hydrogen precipitated at the cathode has a reducing property, which can reduce the oxides on the catalyst surface and clean the catalyst surface, increase the electrochemical active area of ​​the catalyst, and the reduced catalyst further improves the performance of the fuel cell. When the fuel cell is running at high power, the pressure and flow of the gas inside the fuel cell and the water generated by the reaction are relatively large, which can improve the microstructure of the gas diffusion layer and the catalyst layer, increase the transmission channels and reaction area of ​​gas, water and protons, and improve the performance of the fuel cell.

[0147] An embodiment of the present application also provides a vehicle, comprising the above-mentioned online activation system for a fuel cell.

[0148] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments, and the above embodiments are only used to illustrate the technical solution of the present application rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An online activation system for a fuel cell, characterized in that: include: A bidirectional DC converter, a fuel cell, and a vehicle device, wherein the vehicle device comprises: a power battery and an electrical device on the vehicle, wherein two first interfaces of the bidirectional DC converter are respectively connected to two ends of the power battery in the vehicle device, and two second interfaces of the bidirectional DC converter are respectively connected to an anode and a cathode of the fuel cell; The hydrogen inlet pipe of the fuel cell is provided with a hydrogen control valve, the hydrogen circulation pipe of the fuel cell is provided with a hydrogen circulation pump and a hydrogen-water separator, the hydrogen circulation pipe is connected with the hydrogen inlet pipe, and the connecting position of the hydrogen circulation pipe and the hydrogen inlet pipe is located between the hydrogen control valve and the fuel cell; The air intake pipe of the fuel cell is provided with an air control valve, an air compressor, an intercooler and a first humidifier, the air circulation pipe of the fuel cell is provided with an air-water separator, a three-way valve and a second humidifier, the air circulation pipe is connected with the air intake pipe, and the connecting position of the air circulation pipe and the air intake pipe is located between the air control valve and the air compressor; The bidirectional DC converter comprises: a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch, a first resistor, a second resistor, a first capacitor, a second capacitor, a first high-voltage fuse, a second high-voltage fuse, a third high-voltage fuse and a fourth high-voltage fuse; The first switch is respectively connected to the anode of the fuel cell, the high-voltage positive bus and the high-voltage negative bus of the bidirectional DC converter; The second switch is respectively connected to the cathode of the fuel cell, the high-voltage positive bus and the high-voltage negative bus; A first consumption circuit, a first EMC filter, the first capacitor, a step-up / step-down device, a second capacitor, and a second EMC filter are sequentially connected between the high-voltage positive bus and the high-voltage negative bus. A second consumption circuit is also arranged on the high-voltage positive bus. The second consumption circuit is located at an end of the high-voltage positive bus away from the fuel cell. The sixth switch is located at an end of the high-voltage negative bus away from the fuel cell. The first consumption circuit includes: the third switch and the first resistor connected in series. The second consumption circuit includes: the fourth switch, the fifth switch, and the second resistor. The fourth switch is arranged on the high-voltage positive bus. A path formed by the series connection of the fifth switch and the second resistor is connected in parallel to both ends of the fourth switch.

2. The system according to claim 1, characterized in that A plurality of load paths are also connected between the high-voltage positive bus and the high-voltage negative bus, and the plurality of load paths include at least one of the following paths: a path formed in series between the first high-voltage fuse and the air compressor, a path formed in series between the second high-voltage fuse and the cooling water pump, a path formed in series between the third high-voltage fuse and the hydrogen circulation pump, and a path formed in series between the fourth high-voltage fuse and the thermistor; The hydrogen water separator and the air water separator are both provided with a drain valve; The first humidifier and the second humidifier are the same humidifier.

3. A method for online activation of a fuel cell, characterized in that: Applied to the system of claim 1, the method comprises: The fuel cell is activated N times by the online activation system of the fuel cell, each activation cycle includes: hydrogen pump activation and high-power activation, and N is a positive integer greater than or equal to 1; The hydrogen pump activation comprises: When the fuel cell is in a normal operating mode, the state of the fuel cell is adjusted, and the three-way valve is controlled to connect the second humidifier and the air-water separator. At this time, the normal operating mode is to set the end of the bidirectional DC converter connected to the fuel cell to an input current mode; and to set the end of the bidirectional DC converter connected to the vehicle and the power battery to an output voltage mode; controlling the opening of the air control valve and the rotation speed of the air compressor to maintain the gas pressure at the cathode of the fuel cell; If the opening of the air control valve is less than or equal to a preset opening threshold, the air control valve is closed, and the hydrogen control valve, the drain valve of the hydrogen-water separator, and the drain valve of the air-water separator are controlled to maintain the gas pressure difference between the hydrogen side of the fuel cell and the air side of the fuel cell at a target pressure difference; When the output current of the fuel cell is less than a first preset current threshold, the fuel cell is discharged at low power through the bidirectional DC converter; When the output current of the fuel cell is less than a second preset current threshold, setting the fuel cell end of the bidirectional DC converter to an output current mode, and activating the fuel cell with a preset output current and a preset activation time; The high-power activation includes: The working mode of the fuel cell is adjusted to the normal operating mode by the bidirectional DC converter. At this time, the normal operating mode is to set the end of the bidirectional DC converter connected to the fuel cell to the input voltage mode, and the end of the bidirectional DC converter connected to the vehicle and the power battery to the output voltage mode; Controlling the three-way valve to connect the second humidifier with the air exhaust port of the three-way valve; increasing the opening of the air control valve; When the air control valve is fully opened, the fuel cell end of the bidirectional DC converter is set to an input current mode, and the fuel cell is activated at a target activation power and a target activation time; The fuel cell is in a normal operating mode including: The first switch is connected to the high-voltage negative bus, the second switch is connected to the high-voltage positive bus, the fourth switch and the sixth switch are in a closed state, the third switch and the fifth switch are in an open state, the three-way valve is connected to the second humidifier and the air exhaust port, and the air control valve is in a fully open state; The step of adjusting the state of the fuel cell comprises: The gas pressure of the anode of the fuel cell is adjusted to a target anode pressure through the hydrogen control valve, and the gas pressure of the cathode of the fuel cell is adjusted to a target cathode pressure through the air compressor, the three-way valve and the air control valve, wherein the target anode pressure is greater than the target cathode pressure; adjusting the humidity of hydrogen to the target humidity through the hydrogen circulation pump and the hydrogen-water separator, and adjusting the humidity of air to the target humidity through the first humidifier; The low-power discharge of the fuel cell by the bidirectional DC converter comprises: closing the third switch, and opening the third switch when the output current of the fuel cell drops to a second preset current threshold; The step of setting the fuel cell end of the bidirectional DC converter to an output current mode and activating the fuel cell with a preset output current and a preset activation time comprises: The first switch is controlled to be connected to the high-voltage positive bus, and the second switch is controlled to be connected to the high-voltage negative bus.

4. The method according to claim 3, characterized in that The step of performing N cycles of activation on the fuel cell by the online activation system of the fuel cell comprises: Collecting real-time status parameters of the fuel cell, wherein the real-time status parameters include: shutdown storage time of the fuel cell, and operation time of the fuel cell in at least one power interval; Calculating the activation period of the fuel cell according to the real-time state parameter, wherein the activation period is positively correlated with the shutdown storage time and the operating time; If the activation period is greater than or equal to a preset activation time threshold, adjusting the power battery state of the vehicle where the fuel cell is located; If the power battery state is the target battery state, the vehicle energy consumption is within the preset energy consumption range, and the operating time of the fuel cell reaches the preset operating time, the fuel cell is activated for N cycles through the online activation system of the fuel cell. The power battery state is the target battery state, including: the power battery power is within a first preset power range, the power battery temperature is within a first preset temperature range, and the continuous maximum charging power of the power battery is greater than or equal to a first preset proportion of the rated power of the fuel cell.

5. The method according to claim 4, characterized in that The power battery state includes: power battery power and power battery temperature. The adjusting of the power battery state of the vehicle where the fuel cell is located includes: Adjusting the power battery to an average power of a first minimum power and a first maximum power, wherein the first minimum power and the first maximum power are the minimum value and the maximum value of a first preset power range of the power battery before activation; The temperature of the power battery is adjusted to an average temperature of a first minimum temperature and a first maximum temperature by the air conditioner of the power battery, wherein the first minimum temperature and the first maximum temperature are the minimum value and the maximum value of a first preset temperature range of the power battery before activation.

6. The method according to claim 4, characterized in that The method further comprises: During the N-cycle activation process, the real-time status of the power battery is collected in real time, and the real-time status of the power battery includes: the real-time power of the power battery, the real-time temperature of the power battery, and the real-time maximum charging power of the power battery; If the real-time power level of the power battery is not within the second preset power range, and / or the real-time temperature of the power battery is not within the second preset temperature range, and / or the real-time maximum charging power of the power battery is less than a second preset ratio of the rated power of the fuel cell, then the N-cycle activation is exited.

7. The method according to claim 3, characterized in that The step of activating the fuel cell at a target activation power and a target activation time includes: If the target activation power is greater than the continuous rechargeable power of the power battery, and the target activation time corresponding to the target activation power is greater than the maximum charging time that the power battery can withstand, then the fuel cell is controlled to operate at the target activation power for the maximum charging time, and then the fuel cell is controlled to operate at idle speed for the maximum charging time, and then the fuel cell is controlled to operate again at the target activation power for a first time, where the first time is the difference between the target activation time and the maximum charging time.

8. A vehicle, characterized in that: An online activation system for a fuel cell comprising the fuel cell described in claim 1 or 2.

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