A method and apparatus for on-line activation of a fuel cell system

Abstract

The application relates to an online activation method of a fuel cell system and belongs to the technical field of fuel cell systems. The method comprises the following steps: after the fuel cell system receives a shutdown instruction, the fuel cell system enters an online activation program state, starts to perform a pre-activation preparation process, and after the pre-activation preparation process is completed, enters an online activation process; the online activation process comprises the following steps: the fuel cell system is operated at a preset current, air is introduced into a cathode inlet of the fuel cell system, the flow of the introduced air is adjusted from a stack inlet flow to a1, first activation is performed, the flow of the introduced air is continuously adjusted to a2, second activation is performed, the flow of the introduced air is continuously adjusted to a3, and first activation is performed, wherein a1>a2>a3. The online activation method combines hydrogen reduction reaction and a step-by-step activation strategy, maximizes the performance and service life of the stack in continuity, instantaneity and safety, and provides an efficient activation method for the fuel cell system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, and particularly relates to an online activation method and device of a fuel cell system. BACKGROUND

[0002] Fuel cell systems have been a focus of attention as an advanced, efficient, and clean energy conversion technology. However, with long-time operation, the performance of fuel cell stacks gradually deteriorates, which becomes particularly prominent in the application of fuel cell technology. Performance deterioration can lead to a decrease in energy conversion efficiency, a reduction in service life, and even the need for more frequent maintenance, increasing operating costs. Therefore, it is crucial to research and develop effective online activation strategies.

[0003] Traditional fuel cell activation methods usually require external devices and disassembly of some system components, which increases the complexity and cost of system maintenance and requires special safety measures, posing a risk to operators. Moreover, traditional fuel cell activation methods usually need to be performed in a shutdown state, which limits the continuous operation of the system. This shutdown state is unacceptable in some application scenarios, especially in applications that require continuous power supply. In addition, traditional activation methods can only be performed periodically and cannot take immediate action when performance degradation occurs, which can lead to unnecessary performance loss.

[0004] Therefore, with the continuous development of fuel cell technology, the demand for online activation strategies is increasing. Online activation can monitor performance in real time while the system is running and make adjustments when needed without shutdown. This can significantly reduce system downtime, improve system availability and stability. In addition, online activation can detect performance degradation more quickly and take corrective measures, thereby extending system life and reducing operating costs. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the embodiments of the present application includes providing an online activation method of a fuel cell system to restore the performance of the fuel cell system.

[0006] In a first aspect, the embodiments of the present application provide an online activation method of a fuel cell system, comprising: after the fuel cell system receives a shutdown instruction, entering an online activation program state, starting a pre-activation preparation process, and after the pre-activation preparation process is completed, entering an online activation process; the online activation process comprises: making the fuel cell system run at a preset current, simultaneously introducing air into a cathode inlet of the fuel cell system, adjusting the flow of the introduced air from a stack inlet flow to a1, and controlling the inlet air pressure at the cathode inlet to be a first preset pressure value, the fuel cell system maintaining this state for t1 time to complete the first activation; adjusting the flow of the introduced air to a2, the inlet air pressure remaining the first preset pressure value, the fuel cell system maintaining this state for t2 time to complete the second activation; adjusting the flow of the introduced air to a3, the inlet air pressure remaining the first preset pressure value, the fuel cell system maintaining this state for t3 time to complete the third activation; wherein a1>a2>a3; after the first activation ends and before the second activation starts, and after the second activation ends and before the third activation starts, further comprising a switching preparation process, the switching preparation process comprising: adjusting the flow of the introduced air to the stack inlet flow, and adjusting the inlet air pressure to a second preset pressure value, the fuel cell system maintaining this state for t4 time; during the entire online activation process, the pressure on the anode side is controlled to be 20-30 kPa higher than the inlet air pressure.

[0007] The online activation method in the present application is different from the traditional offline activation method. This method can be performed when the fuel cell system is normally running, without shutdown. This reduces the downtime of the system and improves the availability of the system. The online activation method can take action immediately when performance degradation occurs, reducing the degree of performance degradation, prolonging the service life of the system, and reducing the operating cost. By performing system load under anoxic conditions and utilizing the reducing properties of hydrogen atoms, the present application can promote the reduction reaction of oxides on the membrane and catalyst surface of the stack. This helps to clean and restore the active sites of the stack, reduces the resistance, and improves the performance of the fuel cell. By gradually reducing the flow of the introduced air, the present application realizes different degrees of oxide removal, maximizes the cleaning and restoration of the active sites, which helps to improve the performance of the stack. Moreover, gradual activation can reduce the stress and temperature gradient inside the stack, which helps to maintain the structural integrity of the stack and prolong the service life of the stack.

[0008] In some embodiments of the application, a1 is 40-45 g / s; and / or, a2 is 35-38 g / s; and / or, a3 is 26-30 g / s. Gradually reducing the flow rate of air (a1 > a2 > a3) helps to gradually achieve the activation process, and by controlling the flow rate of air within the above ranges, helps to maintain the stability of the air flow. Moreover, gradually reducing the flow rate of air helps to achieve the maximum activation effect. Each activation is targeted for different degree of oxide removal, maximizing the cleanliness and the recovery of active sites.

[0009] In some embodiments of the application, the inlet flow rate is 115-125 g / s. Maintaining the inlet flow rate within the range of 115-125 g / s helps to maintain the performance, life and stability of the cell, while ensuring that the cell obtains proper gas supply under normal operating conditions. Moreover, maintaining the inlet flow rate within the above range also helps to maintain the water balance. Water is a product in the fuel cell, and proper inlet flow rate can help to expel excessive water vapor, avoiding water accumulation, while maintaining sufficient moisture to maintain the wet state of the electrolyte membrane.

[0010] In some embodiments of the application, t1 is 5-10 s; and / or, t2 is 5-10 s; and / or, t3 is 5-10 s. Limiting the activation time of each activation within the range of 5-10 seconds helps to improve the efficiency of activation, reduce downtime, monitor performance in real time and control energy consumption.

[0011] In some embodiments of the application, t1 = t2 = t3. By making the time of each activation equal, a consistent activation effect can be achieved. Equal activation time means that each activation can uniformly process the entire cell system. This can reduce the difference in activation effect, and uniformly improve the performance of the entire system. In addition, using equal activation time can simplify system control, as there is no need to accurately time each activation, which reduces complexity and improves the feasibility of implementation.

[0012] In some embodiments of the application, t1 + t2 + t3 = 20-24 s.

[0013] In some embodiments of the present application, t4 is 8-12s. The purpose of the switching preparation process is to transition the system from the activation state to the normal operation state and to properly prepare the system during this transition. In this stage, the flow of air is adjusted to the in-pile flow, and the air inlet pressure is adjusted to the second preset pressure value to prepare the system to return to normal operation. The purpose of this process is to smoothly transition to prevent unstable or excessive pressure and flow changes when switching from the activation state to the normal operation state. Therefore, the time of each switching preparation process is controlled within 8-12 seconds, and the system can be smoothly switched from the activation state to the normal operation state. This transition period allows the parameters of the system, such as flow and pressure, to gradually return to normal operation values, avoiding sudden and large changes, thereby reducing the impact and instability of the system.

[0014] In some embodiments of the present application, the first preset pressure value is 110-115 kPa; and / or, the second preset pressure value is 130-135 kPa. The above-mentioned online activation reaction of the stack helps to remove oxides in the stack and improve the activity of the catalyst. Controlling the activation pressure to be 110-115 kPa helps to ensure the progress of the reaction, thereby improving the performance of the system; when performing the switching preparation process, increasing the pressure to 130-135 kPa helps to improve the stability of the system. The main purpose of this step is to switch the system from the activation mode back to the normal operation mode. Increasing the pressure helps to reduce the instability that may occur, allowing the system to run smoothly during the switching process.

[0015] In some embodiments of the present application, the preset current is 355-365 A.

[0016] In some embodiments of the present application, the pre-activation preparation process comprises: operating the fuel cell system at a preset current density, and maintaining the temperature of the stack in the fuel cell system at 60-70℃. The pre-activation preparation process helps the system to smoothly switch to the activation process.

[0017] In some embodiments of the present application, the preset current density is 0.8-1.3 A / m 2 .

[0018] In some embodiments of the present application, the pre-activation preparation process further comprises: detecting whether the fuel cell system meets the requirements for entering the activation state, and if the detection is qualified, entering the online activation process; otherwise, the fuel cell system issues an error stop command. By performing system detection in the pre-activation preparation process, the safety, performance optimization and controllability of the system can be confirmed, while reducing the risk of system failure, thereby improving the overall reliability and efficiency of the fuel cell system.

[0019] In some embodiments of the present application, if any cell in the stack is lower than the preset voltage value, the fuel cell system issues an error shutdown instruction.

[0020] In some embodiments of the present application, the preset voltage value is 0.2-0.4V.

[0021] In the second aspect, the embodiments of the present application provide an online activation device of a fuel cell system, which comprises, in sequence, an air compressor, a intercooler, a humidifier and a stack; the humidifier is provided with a humidity adjusting device and the humidity adjusting device is connected to the humidifier; the stack is provided with a radiator and a DC / DC converter, the radiator is used for auxiliary thermal management of the stack, and the DC / DC converter converts and outputs the voltage and current of the stack; the stack is further provided with a hydrogen source and an adjusting valve, the hydrogen source is connected to a hydrogen circulation pipeline of the stack to assist hydrogen circulation, a first pressure sensor and the adjusting valve are arranged on the hydrogen circulation pipeline, the first pressure sensor is used for monitoring the hydrogen pressure value on the hydrogen circulation pipeline, and the adjusting valve is used for adjusting the amount of hydrogen entering the stack.

[0022] In some embodiments of the present application, the online activation device of the fuel cell system further comprises a circulating pump connected to the stack and the hydrogen circulation pipeline, which is used for circulating the unused hydrogen back to the stack to continue participating in the reaction; the circulating pump is further connected with a drain pipeline and an exhaust pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0024] Figure 1 FIG. 1 is a structural schematic diagram of an online activation device of a fuel cell system in the embodiments of the present application;

[0025] Figure 2 FIG. 2 is a flow chart of an online activation method of a fuel cell system in the embodiments of the present application.

[0026] FIG. 1 is a structural schematic diagram of an online activation device of a fuel cell system in the embodiments of the present application; DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0029] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0030] In the description of the present application, it should be noted that the terms "first", "second" and the like are only used to distinguish description, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present application, it should also be noted that, unless otherwise specified and limited, the terms "set", "connected" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] The embodiments of the present application provide an online activation method of a fuel cell system, comprising:

[0033] Step S101. After the fuel cell system receives the shutdown instruction, the online activation program state is entered, and the pre-activation preparation process is started.

[0034] Step S102. Pre-activation preparation process: the fuel cell system is operated at a preset current density, and the temperature of the stack 100 in the fuel cell system is maintained at 60-70℃; wherein the preset current density is 0.8-1.3A / m 2Meanwhile, the on-line monitoring device in the fuel cell system detects whether the fuel cell system meets the requirements for entering the activation state. If the detection is qualified, the fuel cell system enters the on-line activation process. If any cell in the stack 100 is lower than the preset voltage value (0.2-0.4V), the fuel cell system issues an error shutdown instruction. The preset voltage value in the present application can be any value between 0.2-0.4V, for example, 0.2V, 0.25V, 0.3V, 0.35V, or 0.4V.

[0035] By performing the system detection, the system can reach the necessary safety standards and requirements before entering the activation state. This helps to prevent potential problems and dangerous situations, improving the safety of the system. Moreover, the detection can make each component of the fuel cell system in good working condition before entering the activation state. This helps to maximize the effect of activation and ensures that the activation is meaningful, without wasting resources. If the system has problems or does not meet the requirements for the activation state, the detection and corresponding measures can reduce the number of failures or damage during activation, which can prolong the service life of the system and reduce maintenance costs.

[0036] Step S103. On-line activation process: the fuel cell system is operated at a preset current (355-365A), and air is introduced into the cathode inlet of the fuel cell system. The flow rate of the introduced air is adjusted from the stack inlet flow rate (115-125g / s) to a1, and the inlet air pressure at the cathode inlet is controlled to a first preset pressure value. The fuel cell system maintains this state for t1 time to complete the first activation. The flow rate of the introduced air is adjusted to a2, and the inlet air pressure remains at the first preset pressure value. The fuel cell system maintains this state for t2 time to complete the second activation. The flow rate of the introduced air is adjusted to a3, and the inlet air pressure remains at the first preset pressure value. The fuel cell system maintains this state for t3 time to complete the third activation. Wherein, a1>a2>a3; after the first activation ends and before the second activation starts, and after the second activation ends and before the third activation starts, a switching preparation process is also included. The switching preparation process includes: adjusting the flow rate of the introduced air to the stack inlet flow rate, and adjusting the inlet air pressure to a second preset pressure value. The fuel cell system maintains this state for 8-12s. During the entire on-line activation process, the pressure on the anode side is controlled to be higher than the inlet air pressure by 20-30kpa.

[0037] In embodiments of the application, a1 is 40-45 g / s, a2 is 35-38 g / s, and a3 is 26-30 g / s. Gradually reducing the flow rate of the air introduced (a1 > a2 > a3) helps to gradually achieve the activation process, and gradually reducing the oxygen supply can control the rate of the reduction reaction to avoid sudden oxide removal that can cause irreversible damage to the stack 100. At the same time, gradual activation can reduce the stress and temperature gradient inside the stack 100, helping to reduce the thermal expansion and contraction of the materials of the stack 100. This helps to maintain the structural integrity of the stack 100 and prolong the service life of the stack 100. By controlling the flow rate of the air introduced within the above range, it helps to maintain the stability of the air flow. And gradually reducing the flow rate of the air introduced helps to achieve the maximum activation effect. Each activation is targeted at different degrees of oxide removal, maximizing cleanliness and restoring active sites.

[0038] In embodiments of the application, t1 is 5-10 s, t2 is 5-10 s, t3 is 5-10 s, and t1 = t2 = t3, and the total time of the three activations is 20-24 s, i.e. t1 + t2 + t3 = 20-24 s. By making the time of each activation equal, a consistent activation effect can be achieved. Equal activation time means that each activation can uniformly treat the entire battery system. This can reduce the difference in activation effect and uniformly improve the performance of the entire system. In addition, using equal activation time can simplify system control, as there is no need to accurately time each activation, which reduces complexity and improves the feasibility of implementation. Completing each activation within 5-10 s can quickly reduce the oxides in the battery, remove contaminants, and improve the performance of the battery. Moreover, an activation time of 5-10 s means that the battery system needs less time for online activation, which can reduce the downtime of the system and improve the availability of the system. Because the time of each activation is short, the system can activate more frequently to monitor performance and take corrective action. This can detect performance degradation faster and take action, helping to extend the service life of the system. It can also help to control energy consumption, as the system needs to consume hydrogen during activation. Shorter activation time helps to maintain performance while saving hydrogen.

[0039] In the embodiments of the present application, the first preset pressure value is 110-115 kPa, and the second preset pressure value is 130-135 kPa. The above-mentioned online activation reaction of the fuel cell stack 100 helps to remove the oxides in the fuel cell stack 100 and improve the activity of the catalyst. Controlling the activation pressure at 110-115 kPa helps to ensure the progress of the reaction, thereby improving the performance of the system; when the switching preparation process is performed, increasing the pressure to 130-135 kPa helps to improve the stability of the system. The main purpose of this step is to switch the system from the activation mode back to the normal operation mode. Increasing the pressure helps to reduce the instability that may occur, so that the system can run smoothly during the switching process.

[0040] Step S104. Complete shutdown: After the fuel cell system completes the activation, it enters the normal shutdown purging process and completes the shutdown.

[0041] Activation completion judgment: The judgment method is the increase of the voltage of the fuel cell stack 100 under the same current after starting again. If the effect is not very significant after single activation, the reason may be that there are not many impurities attached to the inside of the fuel cell stack 100, and the activation effect of single activation is limited. The fuel cell system will be activated after each shutdown, so as to make the fuel cell stack 100 run at the optimal performance as much as possible.

[0042] The online activation method utilizes the reduction characteristics of hydrogen atoms. In the oxygen-deficient state, the oxides on the membrane and catalyst surface of the fuel cell stack 100 will undergo a reduction reaction with the permeated hydrogen ions. This process can clean the catalyst surface, reduce the content of oxides, thereby increasing the active sites and improving the performance of the fuel cell. During the online activation process, the system is pulled under an oxygen-deficient state, forcing the cathode oxides to undergo a reduction reaction with the permeated hydrogen ions. This helps to clean and restore the active sites of the fuel cell stack 100, reducing the resistance. At the same time, through multiple activation processes, gradually reducing the flow of air introduced, different degrees of oxide removal are achieved, maximizing the cleanliness and restoration of active sites, which helps to improve the performance of the fuel cell stack 100.

[0043] The application further provides a fuel cell system online activation device, which comprises, sequentially connected, an air compressor 600, a intercooler 400, a humidifier 500 and a stack 100; the humidifier 500 is provided with a humidity adjusting device and the humidity adjusting device is connected to the humidifier 500; the stack 100 is provided with a radiator and a DC / DC converter, the radiator is used for auxiliary heat management of the stack 100, and the DC / DC converter converts and outputs voltage and current of the stack 100; the stack 100 is further provided with a hydrogen source 200, the hydrogen source 200 is connected to a hydrogen circulation pipeline of the stack 100 to assist hydrogen circulation, a first pressure sensor 202 and an adjusting valve 201 are arranged on the hydrogen circulation pipeline, the first pressure sensor 202 is used for monitoring a hydrogen pressure value on the hydrogen circulation pipeline, and the adjusting valve 201 is used for adjusting the amount of hydrogen entering the stack 100.

[0044] In the application, the device further comprises a circulating pump 300 connected to the stack 100 and the hydrogen circulation pipeline, which is used for circulating the unused hydrogen back to the stack 100 to continue participating in the reaction; the circulating pump 300 is further connected with a drainage pipeline and an exhaust pipeline. A second pressure sensor 301 is arranged on the pipeline connecting the circulating pump 300 and the stack 100; a drainage valve 303 is arranged on the drainage pipeline, and the exhaust pipeline is mainly used for discharging nitrogen in the air entering the stack 100, and a nitrogen discharge valve 302 is arranged on the exhaust pipeline.

[0045] In the application, the place where the humidifier 500 is connected to the stack 100 is provided with two pipelines, namely a first pipeline and a second pipeline, the first pipeline is mainly an air inlet pipeline, air enters from the air compressor 600, sequentially passes through the intercooler 400 and the humidifier 500, enters the first pipeline, and then reaches the stack 100, a front stop valve 502, a first temperature sensor 504 and a third pressure sensor 505 are arranged on the first pipeline. The second pipeline is mainly used for discharging the unreacted air in the stack 100, and a rear stop valve 503 and a second temperature sensor 506 are arranged on the second pipeline; the unreacted air in the stack 100 enters the humidifier 500 through the second pipeline, the humidifier 500 is connected with a third pipeline, the unreacted air in the stack 100 is discharged from the third pipeline, and a back pressure valve 501 is arranged on the third pipeline. At the same time, the residual air in the humidifier 500 is also discharged from the third pipeline. The intercooler 400 is connected with a fourth pipeline, a bypass valve 401 is arranged on the fourth pipeline, and the residual air in the intercooler 400 is discharged from the fourth pipeline. The residual air in the intercooler 400 and the humidifier 500 is timely discharged from the fourth pipeline and the third pipeline respectively, which can also reduce the probability of surge of the air compressor 600.

[0046] The features and performances of the application are further described in detail in combination with the embodiments.

[0047] Embodiment 1

[0048] Figure 1 This is a schematic diagram of the online activation device for the fuel cell system in an embodiment of this application. Please refer to... Figure 1 .

[0049] This embodiment provides an online activation device for a fuel cell system, such as... Figure 1 As shown, the device includes an air compressor 600, an intercooler 400, a humidifier 500, and a fuel cell stack 100 connected in sequence. The humidifier 500 is equipped with a humidity regulating device connected in parallel to the humidifier 500. The fuel cell stack 100 is equipped with a heat sink and a DC / DC converter. The heat sink is used for auxiliary thermal management of the fuel cell stack 100, and the DC / DC converter converts the voltage and current of the fuel cell stack 100 for output. The fuel cell stack 100 is also equipped with a hydrogen source 200 and a regulating valve 201. The hydrogen source 200 is connected to the hydrogen circulation pipeline of the fuel cell stack 100 to assist hydrogen circulation. A first pressure sensor 202 and a regulating valve 201 are installed on the hydrogen circulation pipeline. The regulating valve 201 is used to regulate the amount of hydrogen entering the fuel cell stack 100.

[0050] The device also includes a circulation pump 300, which is connected to the fuel cell stack 100 and the hydrogen circulation pipeline. The circulation pump 300 is used to circulate unused hydrogen back into the fuel cell stack 100 to continue participating in the reaction. The circulation pump 300 is also connected to a drain pipeline and an exhaust pipeline. A drain valve 303 is installed on the drain pipeline, and the exhaust pipeline is mainly used to discharge nitrogen gas from the air entering the fuel cell stack 100. A nitrogen venting valve 302 is installed on the exhaust pipeline.

[0051] Two pipes are installed at the connection point between the humidifier 500 and the fuel cell stack 100: a first pipe and a second pipe. The first pipe is primarily the air intake pipe. Air enters from the air compressor 600, passes through the intercooler 400 and the humidifier 500, enters the first pipe, and then reaches the fuel cell stack 100. A front shut-off valve 502, a first temperature sensor 504, and a pressure sensor are installed on the first pipe. The second pipe is mainly used to discharge unreacted air from the fuel cell stack 100. A rear shut-off valve 503 and a second temperature sensor 506 are installed on the second pipe. Unreacted air from the fuel cell stack 100 enters the humidifier 500 through the second pipe. The humidifier 500 is connected to a third pipe, through which unreacted air from the fuel cell stack 100 is discharged. A back pressure valve 501 is installed on the third pipe. Simultaneously, residual air in the humidifier 500 is also discharged through the third pipe. Intercooler 400 is connected to a fourth pipe, on which a bypass valve 401 is installed. Residual air in intercooler 400 is discharged through the fourth pipe. Residual air in intercooler 400 and humidifier 500 is discharged in a timely manner through the fourth and third pipes, respectively, which can also reduce the probability of surge in air compressor 600.

[0052] Example 2

[0053] Figure 1 Fig. 1 is a schematic diagram of the structure of an online activation device for a fuel cell system according to an embodiment of the present application; Figure 2 Fig. 2 is a flow chart of an online activation method for a fuel cell system according to an embodiment of the present application; please refer to Figure 1 and Figure 2 .

[0054] The present embodiment provides an online activation method for a fuel cell system, which uses the device provided in Embodiment 1, and the method comprises the following steps:

[0055] (1) After receiving a shutdown instruction, the fuel cell system enters an online activation program state and starts the pre-activation preparation process.

[0056] (2) Pre-activation preparation process

[0057] The fuel cell system is operated at 1.2 A / m 2 The online monitoring device in the fuel cell system detects whether the fuel cell system meets the requirements for entering the activation state, and if the detection is qualified, the fuel cell system enters the online activation process; if any cell in the stack 100 is lower than 0.2 V, the fuel cell system issues an error shutdown instruction.

[0058] (3) Online activation process

[0059] After the detection finds that the fuel cell system meets the requirements for entering the activation state, the fuel cell system enters the online activation process, which comprises the following steps:

[0060] The fuel cell system is operated at 360 A for 2 min, air is introduced into the cathode inlet of the fuel cell system, the air enters the system through the air compressor 600, the air flow rate is adjusted from the stack flow rate 120 g / s to 40 g / s, the air inlet pressure at the cathode inlet is controlled to be 110 kPa, the fuel cell system is maintained in this state for 7 s to complete the first activation; the air flow rate is adjusted to the stack flow rate 120 g / s, the air inlet pressure is adjusted to 130 kPa, the fuel cell system is maintained in this state for 10 s to enter the second activation; the air flow rate is adjusted to 35 g / s, the air inlet pressure at the cathode inlet is controlled to be 110 kPa, the fuel cell system is maintained in this state for 7 s to complete the second activation; the air flow rate is adjusted to the stack flow rate 120 g / s, the air inlet pressure is adjusted to 130 kPa, the fuel cell system is maintained in this state for 10 s to enter the third activation; the air flow rate is adjusted to 26 g / s, the air inlet pressure at the cathode inlet is controlled to be 110 kPa, the fuel cell system is maintained in this state for 7 s to complete the third activation. During the entire process of the online activation process, the pressure on the anode side is controlled to be higher than the air inlet pressure by 20 kPa.

[0061] (4) complete shutdown

[0062] The fuel cell system enters a normal shutdown purge process after completing activation, and completes shutdown.

[0063] The embodiments described above are part of, but not all, embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application, but merely to represent selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

Claims

1. A method for on-line activation of a fuel cell system, characterized by, The fuel cell system receives a shutdown instruction, enters an online activation procedure state, and starts a pre-activation preparation process, and after the pre-activation preparation process is completed, enters an online activation process; The online activation process comprises: The fuel cell system is operated at a preset current, air is introduced into the cathode inlet of the fuel cell system, the flow of the introduced air is adjusted from a stack inlet flow to a1, the inlet air pressure at the cathode inlet is controlled to be a first preset pressure value, the fuel cell system is maintained in this state for t1 time to complete the first activation; The flow of the introduced air is adjusted to a2, the inlet air pressure remains the first preset pressure value, and the fuel cell system is maintained in this state for t2 time to complete the second activation; The flow of the introduced air is adjusted to a3, the inlet air pressure remains the first preset pressure value, and the fuel cell system is maintained in this state for t3 time to complete the third activation; Wherein, a1>a2>a3; After the end of the first activation and before the start of the second activation, and after the end of the second activation and before the start of the third activation, a switching preparation process is further included, which comprises: adjusting the flow of the introduced air to the stack inlet flow, and adjusting the inlet air pressure to a second preset pressure value, and maintaining the fuel cell system in this state for t4 time; During the entire process of the online activation process, the pressure on the anode side is controlled to be 20-30kpa higher than the inlet air pressure; Wherein, the a1 is 40-45g / s; the a2 is 35-38g / s; the a3 is 26-30g / s; The first preset pressure value is 110-115kpa; and the second preset pressure value is 130-135kpa. The stack inlet flow is 115-125g / s.

2. The method of claim 1, wherein, The t1 is 5-10s; and / or, the t2 is 5-10s; and / or, the t3 is 5-10s.

3. The method of claim 1, wherein, The t1=t2=t3.

4. The method of claim 3, wherein, The t1+t2+t3=20-24s.

5. The method of claim 3, wherein, The t4 is 8-12s.

6. The method of claim 3, wherein, The preset current is 355-365A.

7. The method according to any one of claims 1 to 6, characterized in that, The pre-activation preparation process comprises:

8. The method according to any one of claims 1-6, characterized in that, The fuel cell system is operated at a preset current density, and the temperature of the stack in the fuel cell system is maintained at 60-70℃. The preset current density is 0.8-1.3A / m².

9. The method of claim 8, wherein, The pre-activation preparation process further comprises:

10. The method of claim 9, wherein, Detecting whether the fuel cell system meets the requirements for entering the activation state, if the detection is qualified, entering the online activation process; otherwise, the fuel cell system issues an error shutdown instruction. If any cell in the stack is lower than a preset voltage value, the fuel cell system issues the error shutdown instruction.

11. The method of claim 10, wherein, The preset voltage value is 0.2-0.4V.

12. The method of claim 11, wherein, It comprises a compressor, a intercooler, a humidifier and a stack connected in sequence; 13. A fuel cell system on-line activation apparatus according to any one of claims 1 to 12, characterized by, ​ The humidifier is provided with a humidity adjusting device connected to the humidifier; the electric pile is provided with a radiator for electric pile auxiliary heat management and a DC / DC converter for converting and outputting electric pile voltage and current; the electric pile is further provided with a hydrogen source connected to an electric pile hydrogen circulation pipeline for auxiliary hydrogen circulation, the hydrogen circulation pipeline is provided with a first pressure sensor for monitoring the hydrogen pressure value on the hydrogen circulation pipeline and an adjusting valve for adjusting the amount of hydrogen entering the electric pile.

14. The apparatus of claim 13, wherein, A circulating pump is further included, which is connected to the electric pile and the hydrogen circulation pipeline for circulating the unused hydrogen back to the electric pile to continue participating in the reaction. The circulating pump is further connected with a drain pipeline and an exhaust pipeline.

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