Online activation method and device for fuel cell system

Abstract

The invention relates to an online activation method for a fuel cell system, and belongs to the technical field of fuel cells. The method comprises the following steps: after receiving a shutdown instruction, the fuel cell system enters an on-line activation program state, starts a preparation process before activation, and enters an on-line activation process after the preparation process before activation is completed; the on-line activation process comprises the following steps: enabling the fuel cell system to operate under a preset current, introducing air into a cathode inlet of the fuel cell system, adjusting the flow of the introduced air to a1 from the in-pile flow, and carrying out first activation; continuously adjusting the flow of the introduced air to a2, and performing second activation; continuously adjusting the flow of the introduced air to a3, and performing first activation; wherein a1 > a2 > a3. The online activation method combines a hydrogen reduction reaction and a step-by-step activation strategy so as to continuously, instantly and safely maximize the performance and the service life of the electric pile, and an efficient activation method is provided for a fuel cell system.

Description

Technical Field

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

[0002] As an advanced, efficient and clean energy conversion technology, fuel cell systems have always attracted much attention. However, with long-term operation, the performance of fuel cell stacks will gradually decay, and this problem becomes particularly prominent in the application of fuel cell technology. Performance degradation may lead to reduced energy conversion efficiency, shortened life, and even require 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. The use of external devices increases the complexity and cost of system maintenance and requires special safety measures, which poses risks to operators. In addition, 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 certain application scenarios, especially those that require continuous power supply. In addition, traditional activation methods can usually only be performed periodically, and measures cannot be taken immediately when performance degradation occurs, which may lead to unnecessary performance loss.

[0004] Therefore, as fuel cell technology continues to develop, the demand for online activation strategies is also increasing. Online activation can monitor performance in real time while the system is running and make adjustments when necessary without shutting down the system. This can significantly reduce system downtime and 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 of the invention

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

[0006] In a first aspect, an embodiment of the present application provides an online activation method for a fuel cell system, comprising: after the fuel cell system receives a shutdown command, it enters an online activation program state and starts a pre-activation preparation process, and after the pre-activation preparation process is completed, it enters an online activation process; the online activation process comprises: operating the fuel cell system at a preset current, while introducing air into the cathode inlet of the fuel cell system, adjusting the flow rate of the introduced air from the stack flow rate to a1, and controlling the intake pressure at the cathode inlet to a first preset pressure value, the fuel cell system maintains this state for t1 time, and completes the first activation; adjusting the flow rate of the introduced air to a2, and maintaining the intake pressure at the first preset pressure value, the fuel cell The system maintains this state for t2 time and completes the second activation; the flow rate of the incoming air is adjusted to a3, the intake pressure is maintained at the first preset pressure value, the fuel cell system maintains this state for t3 time and completes the third activation; wherein, a1>a2>a3; after the first activation is completed and before the second activation begins, as well as after the second activation is completed and before the third activation begins, it also includes a switching preparation process, the switching preparation process includes: adjusting the flow rate of the incoming air to the stack flow rate, and adjusting the intake pressure to the second preset pressure value, the fuel cell system maintains 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 intake pressure.

[0007] The online activation method in this application is different from the traditional offline activation method. This method can be performed when the fuel cell system is operating normally without shutting down. This reduces the downtime of the system and improves the availability of the system. The online activation method can take immediate action when performance degradation occurs, reduce the degree of performance degradation, extend the life of the system, and reduce operating costs. This application uses the reduction characteristics of hydrogen atoms to promote the reduction reaction of oxides on the surface of the stack membrane and catalyst by loading the system under anoxic conditions. This helps to clean and restore the active sites of the stack, reduce resistance, and improve the performance of the fuel cell. In this application, by gradually reducing the flow rate of air introduced, different degrees of oxide removal are achieved, and the cleanliness and recovery of active sites are maximized, which helps to improve the performance of the stack. Moreover, gradual activation can reduce the stress and temperature gradient inside the stack, help maintain the structural integrity of the stack, and extend the service life of the stack.

[0008] In some embodiments of the present 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 the incoming air (a1>a2>a3) helps to gradually achieve the activation process, and by controlling the flow rate of the incoming air within the above range, it helps to maintain the stability of the air flow. In addition, gradually reducing the flow rate of the incoming air helps to achieve the maximum activation effect. Each activation targets different degrees of oxide removal to maximize the cleanliness and recovery of active sites.

[0009] In some embodiments of the present application, the stack flow rate is 115-125g / s. Maintaining the stack flow rate within the range of 115-125g / s helps maintain the performance, life and stability of the battery, while ensuring that the battery obtains appropriate gas supply under normal operating conditions. In addition, maintaining the stack flow rate within the above range also helps maintain water balance. Water is a product in the fuel cell, and an appropriate amount of stack flow rate can help discharge excess water vapor and avoid moisture accumulation, while maintaining sufficient moisture to maintain the wet state of the electrolyte membrane.

[0010] In some embodiments of the present application, t1 is 5-10 seconds; and / or, t2 is 5-10 seconds; and / or, t3 is 5-10 seconds. Limiting each activation time to 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 present application, t1=t2=t3. By making the time of each activation equal, a consistent activation effect can be obtained. Equal activation time means that each activation can evenly treat the entire battery system. This can reduce the difference in activation effect and evenly improve the performance of the entire system. In addition, using equal activation time can simplify system control because there is no need to accurately time the time of each activation, which reduces complexity and improves the feasibility of implementation.

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

[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 activated state to the normal operating state, and to prepare the system properly during this transition period. At this stage, the flow rate of the incoming air is adjusted to the stack flow rate, and the intake 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 achieve a smooth transition to prevent unstable or excessive pressure and flow changes when the system switches from the activated state to the normal operating state. Therefore, the time of each switching preparation process is controlled within 8-12 seconds, and the system can smoothly switch from the activated state to the normal operating state. This transition period allows the system parameters (such as flow and pressure) to gradually return to normal operating values, avoiding sudden and drastic 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. Carrying out the above-mentioned online activation reaction on the fuel cell stack helps to remove oxides in the fuel cell stack and improve the activity of the catalyst. Controlling the activation pressure at 110-115 kPa helps to ensure the reaction and thus improve the system performance. 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 activation mode back to normal operating mode. Increasing the pressure helps to reduce possible instability and enables the system to operate smoothly during the switching process.

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

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

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

[0018] In some embodiments of the present application, the pre-activation preparation process also includes: detecting whether the fuel cell system meets the requirements for entering the activation state. If the detection is qualified, the online activation process is entered; otherwise, the fuel cell system issues an error shutdown instruction. 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 the voltage of any battery in the fuel cell stack is lower than a preset voltage value, the fuel cell system issues an error shutdown command.

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

[0021] In the second aspect, an embodiment of the present application provides an online activation device for a fuel cell system, comprising an air compressor, an intercooler, a humidifier and a fuel cell stack connected in sequence; the humidifier is provided with a humidity regulating device and the humidity regulating device is connected to the humidifier; the fuel cell stack is provided with a radiator and a DC / DC converter, the radiator is used for auxiliary thermal management of the fuel cell stack, and the DC / DC converter converts the voltage and current of the fuel cell stack for output; a hydrogen source and a regulating valve are also provided in the fuel cell stack, the hydrogen source is connected to the hydrogen circulation pipeline of the fuel cell stack to assist hydrogen circulation, and a first pressure sensor and a regulating valve are provided on the hydrogen circulation pipeline, the first pressure sensor is used to monitor the hydrogen pressure value on the hydrogen circulation pipeline, and the regulating valve is used to regulate the amount of hydrogen entering the fuel cell stack.

[0022] In some embodiments of the present application, the fuel cell system online activation device also includes a circulation pump, which is connected to the fuel cell stack and the hydrogen circulation pipeline, and is used to circulate unused hydrogen back to the fuel cell stack to continue to participate in the reaction; the circulation pump is also connected to a drainage pipeline and an exhaust pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of the structure of the online activation device for the fuel cell system in the embodiment of the present application;

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

[0026] Icons: 100-fuel cell stack; 200-hydrogen source; 201-regulating valve; 202-first pressure sensor; 300-circulating pump; 301-second pressure sensor; 302-nitrogen exhaust valve; 303-drain valve; 400-intercooler; 401-bypass valve; 500-humidifier; 501-back pressure valve; 502-front stop valve; 503-rear stop valve; 504-first temperature sensor; 505-third pressure sensor; 506-second temperature sensor; 600-air compressor. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here 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 accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

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

[0031] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] The present application embodiment provides a fuel cell system online activation method, comprising:

[0033] Step S101. After receiving the shutdown command, the fuel cell system enters the online activation program state and starts the pre-activation preparation process.

[0034] Step S102. Pre-activation preparation process: operate the fuel cell system at a preset current density, and maintain the temperature of the fuel cell stack 100 in the fuel cell system at 60-70°C; wherein the preset current density is 0.8-1.3A / m 2At the same time, the online monitoring device in the fuel cell system will detect whether the fuel cell system meets the requirements for entering the activation state. If the detection is qualified, it will enter the online activation process; if any battery in the stack 100 is lower than the preset voltage value (0.2-0.4V), the fuel cell system will issue an error shutdown command. The preset voltage value of this application can be any value between 0.2-0.4V, such as 0.2V, 0.25V, 0.3V, 0.35V, 0.4V.

[0035] By conducting system testing, the system can meet the necessary safety standards and requirements before entering the activation state. This helps prevent potential problems and dangerous situations and improves the safety of the system. Moreover, testing can ensure that all components of the fuel cell system are in good working condition before entering the activation state. This helps to maximize the effect of activation and ensure that activation is meaningful without wasting resources. If there is a problem with the system or it does not meet the requirements of the activation state, by testing and taking appropriate measures, the number of failures or damages during activation can be reduced, which can extend the system life and reduce maintenance costs.

[0036] Step S103. Online activation process: operate the fuel cell system at a preset current (355-365A), and at the same time introduce air into the cathode inlet of the fuel cell system, adjust the flow rate of the air introduced from the stack flow rate (115-125g / s) to a1, and control the intake pressure at the cathode inlet to the first preset pressure value, the fuel cell system maintains this state for t1 time, and completes the first activation; adjust the flow rate of the air introduced to a2, the intake pressure maintains the first preset pressure value, the fuel cell system maintains this state for t2 time, and completes the second activation; adjust the flow rate of the air introduced a3, the intake pressure maintains the first preset pressure value, the fuel cell system maintains this state for t3 seconds, and the third activation is completed; wherein, a1>a2>a3; after the first activation is completed and before the second activation begins, as well as after the second activation is completed and before the third activation begins, a switching preparation process is also included, the switching preparation process includes: adjusting the flow rate of the incoming air to the stack flow rate, and adjusting the intake pressure to the second preset pressure value, the fuel cell system maintains this state for 8-12 seconds; during the entire process of the online activation process, the pressure on the anode side is controlled to be 20-30 kPa higher than the intake pressure.

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

[0038] In an embodiment of the present application, t1 is 5-10s, t2 is 5-10s, t3 is 5-10s, and t1=t2=t3, and the total time of three activations is 20-24s, that is, t1+t2+t3=20-24s. By making the time of each activation equal, a consistent activation effect can be obtained. Equal activation time means that each activation can evenly treat the entire battery system. This can reduce the difference in activation effect and evenly improve the performance of the entire system. In addition, using equal activation time can simplify system control because there is no need to accurately time each activation, which reduces complexity and improves the feasibility of implementation. Completing each activation within 5-10s can quickly reduce the oxides in the battery, remove pollutants, and improve the performance of the battery. Moreover, the activation time of 5-10s 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. Due to the short activation time each time, the system can be activated more frequently to monitor performance and take corrective measures. This can detect performance degradation more quickly and take action, helping to extend the life of the system. It can also help control energy consumption, as the system consumes hydrogen during activation. Shorter activation times can help maintain performance while conserving hydrogen.

[0039] In an embodiment of the present application, the first preset pressure value is 110-115 kPa, and the second preset pressure value is 130-135 kPa. Performing the above-mentioned online activation reaction on the fuel cell stack 100 helps to remove 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 reaction, thereby improving system performance; 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 activation mode back to normal operating mode. Increasing the pressure helps to reduce possible instability and enables the system to operate smoothly during the switching process.

[0040] Step S104. Shutdown completion: After activation is completed, the fuel cell system enters a normal shutdown purge process to complete shutdown.

[0041] Activation completion judgment: The judgment method is the increase in the voltage of the battery stack 100 under the same current after restarting. If the effect is not very significant after a single activation, the reason may be that there are not many impurities attached to the inside of the battery stack 100 at this time, and the activation effect of a single time is limited; the fuel cell system will be activated each time it is shut down, so as to enable the battery stack 100 to operate at the best performance as much as possible.

[0042] This online activation method utilizes the reduction characteristics of hydrogen atoms. In an oxygen-deficient state, the oxides on the membrane and catalyst surface of the stack 100 will undergo a reduction reaction with the infiltrated hydrogen ions. This process can clean the catalyst surface and 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 loaded in an oxygen-deficient state, forcing the cathode oxide to undergo a reduction reaction with the infiltrated hydrogen ions. This helps to clean and restore the active sites of the stack 100 and reduce resistance. At the same time, through multiple activation processes, the flow rate of air is gradually reduced to achieve different degrees of oxide removal, maximize cleanliness and recovery of active sites, which helps to improve the performance of the stack 100.

[0043] An embodiment of the present application also provides an online activation device for a fuel cell system, comprising an air compressor 600, an intercooler 400, a humidifier 500 and a fuel cell stack 100 connected in sequence; the humidifier 500 is provided with a humidity regulating device and the humidity regulating device is connected to the humidifier 500; the fuel cell stack 100 is provided with a radiator and a DC / DC converter, the radiator 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 provided with a hydrogen source 200, the hydrogen source 200 is connected to the hydrogen circulation pipeline of the fuel cell stack 100 to assist hydrogen circulation, and a first pressure sensor 202 and a regulating valve 201 are arranged on the hydrogen circulation pipeline, the first pressure sensor 202 is used to monitor the hydrogen pressure value on the hydrogen circulation pipeline, and the regulating valve 201 is used to adjust the amount of hydrogen entering the fuel cell stack 100.

[0044] In the present application, the device further includes a circulation pump 300, which is connected to the stack 100 and the hydrogen circulation pipeline, and is used to circulate the unused hydrogen back to the stack 100 to continue to participate in the reaction; the circulation pump 300 is also connected to a drainage pipeline and an exhaust pipeline. A second pressure sensor 301 is provided on the pipeline connecting the circulation pump 300 and the stack 100; a drainage valve 303 is provided on the drainage pipeline, and the exhaust pipeline is mainly used to discharge nitrogen in the air entering the stack 100, and a nitrogen exhaust valve 302 is provided on the exhaust pipeline.

[0045] In the present application, two pipelines are provided at the place where the humidifier 500 is connected to the stack 100, namely the first pipeline and the second pipeline. The first pipeline is mainly the air intake pipeline. After the air enters from the air compressor 600, it passes through the intercooler 400 and the humidifier 500 in sequence, enters the first pipeline, and then reaches the stack 100. The first pipeline is provided with a front stop valve 502, a first temperature sensor 504 and a third pressure sensor 505. The second pipeline is mainly used to discharge the unreacted air in the stack 100. The second pipeline is provided with a rear stop valve 503 and a second temperature sensor 506; the unreacted air in the stack 100 enters the humidifier 500 through the second pipeline, the humidifier 500 is connected to the third pipeline, the unreacted air in the stack 100 is discharged from the third pipeline, and the back pressure valve 501 is provided 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 to a fourth pipeline, and a bypass valve 401 is provided 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 discharged from the fourth pipeline and the third pipeline respectively in a timely manner, which can also reduce the probability of surging of the air compressor 600.

[0046] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0047] Example 1

[0048] Figure 1 This is a schematic diagram of the structure of the online activation device for the fuel cell system in the embodiment of the present 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, it includes an air compressor 600, an intercooler 400, a humidifier 500 and a fuel cell stack 100 connected in sequence; the humidifier 500 is provided with a humidity regulating device and the humidity regulating device is connected to the humidifier 500; a radiator and a DC / DC converter are provided in the fuel cell stack 100, the radiator 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 into output; the fuel cell stack 100 is also provided 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, and a first pressure sensor 202 and a regulating valve 201 are provided on the hydrogen circulation pipeline, and the regulating valve 201 is used to adjust 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, and is used to circulate the unused hydrogen back to the fuel cell stack 100 to continue to participate in the reaction; the circulation pump 300 is also connected to a drainage pipeline and an exhaust pipeline. A drainage valve 303 is provided on the drainage pipeline, and the exhaust pipeline is mainly used to discharge nitrogen in the air entering the fuel cell stack 100, and a nitrogen exhaust valve 302 is provided on the exhaust pipeline.

[0051] Two pipelines are provided at the place where the humidifier 500 is connected to the stack 100, namely the first pipeline and the second pipeline. The first pipeline is mainly the air intake pipeline. After the air enters from the air compressor 600, it passes through the intercooler 400 and the humidifier 500 in sequence, enters the first pipeline, and then reaches the stack 100. The first pipeline is provided with a front stop valve 502, a first temperature sensor 504 and a pressure sensor. The second pipeline is mainly used to discharge the unreacted air in the stack 100. The second pipeline is provided with a rear stop valve 503 and a second temperature sensor 506; the unreacted air in the stack 100 enters the humidifier 500 through the second pipeline. The humidifier 500 is connected to the third pipeline. The unreacted air in the stack 100 is discharged from the third pipeline. The third pipeline is provided with a back pressure valve 501. At the same time, the residual air in the humidifier 500 is also discharged from the third pipeline. The intercooler 400 is connected to a fourth pipeline, and a bypass valve 401 is provided 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 discharged from the fourth pipeline and the third pipeline respectively in a timely manner, which can also reduce the probability of surging of the air compressor 600.

[0052] Example 2

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

[0054] This embodiment provides a method for online activation of a fuel cell system, using the device provided in Embodiment 1, the method comprising:

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

[0056] (2) Preparation process before activation

[0057] Make the fuel cell system at 1.2A / m 2 The temperature of the stack 100 in the fuel cell system is maintained at 65°C. At the same time, the online monitoring device in the fuel cell system will detect whether the fuel cell system meets the requirements for entering the activation state. If the detection is qualified, it will enter the online activation process; if any battery in the stack 100 is lower than 0.2V, the fuel cell system will issue an error shutdown command.

[0058] (3) Online activation process

[0059] After the fuel cell system is found to meet the requirements for entering the activation state, the fuel cell system enters the online activation process, which includes:

[0060] The fuel cell system was operated at 360A for 2 minutes. At the same time, air was introduced into the cathode inlet of the fuel cell system. The air entered the system through the air compressor 600. The flow rate of the introduced air was adjusted from the stack flow rate of 120 g / s to 40 g / s, and the intake pressure at the cathode inlet was controlled to be 110 kPa. The fuel cell system maintained this state for 7 seconds to complete the first activation. The air flow rate was adjusted to the stack flow rate of 120 g / s, and the intake pressure was adjusted to 130 kPa. The fuel cell system maintained this state for 10 seconds and then entered Second activation: adjust the air flow rate to 35g / s, and control the intake pressure at the cathode inlet to 110kpa. The fuel cell system maintains this state for 7s to complete the second activation; adjust the air flow rate to 120g / s for the stack flow rate, and adjust the intake pressure to 130kpa. The fuel cell system maintains this state for 10s before entering the third activation; adjust the air flow rate to 26g / s, and control the intake pressure at the cathode inlet to 110kpa. The fuel cell system maintains this state for 7s to complete the third activation. During the entire online activation process, the pressure on the anode side is controlled to be 20kpa higher than the intake pressure.

[0061] (4) Complete shutdown

[0062] After the fuel cell system is activated, it enters the normal shutdown purge process and completes the shutdown.

[0063] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A fuel cell system online activation method, characterized in that: include: After receiving the shutdown command, the fuel cell system enters the online activation program state and starts the pre-activation preparation process. After the pre-activation preparation process is completed, the online activation process is entered; The online activation process comprises: The fuel cell system is operated at a preset current, and air is introduced into the cathode inlet of the fuel cell system, the flow rate of the air introduced is adjusted from the stack flow rate to a1, and the intake pressure at the cathode inlet is controlled to be a first preset pressure value, and the fuel cell system maintains this state for t1 time to complete the first activation; The flow rate of the air is adjusted to a2, the intake pressure is maintained at the first preset pressure value, and the fuel cell system maintains this state for t2 time to complete the second activation; The flow rate of the air is adjusted to a3, the intake pressure is maintained at the first preset pressure value, and the fuel cell system maintains this state for t3 time to complete the third activation; Among them, a1>a2>a3; After the first activation is completed and before the second activation is started, and after the second activation is completed and before the third activation is started, a switching preparation process is also included, and the switching preparation process includes: adjusting the flow rate of the air introduced to the stack flow rate, and adjusting the intake pressure to a second preset pressure value, and the fuel cell system maintains this state for t4 time; During the entire process of the online activation step, the pressure on the anode side is controlled to be 20-30 kPa higher than the intake pressure.

2. The method according to claim 1, characterized in that a1 is 40-45 g / s; and / or a2 is 35-38 g / s; and / or a3 is 26-30 g / s; Optionally, the feed flow rate is 115-125 g / s.

3. The method according to claim 1, characterized in that: The t1 is 5-10s; and / or, the t2 is 5-10s; and / or, the t3 is 5-10s; Optionally, t1=t2=t3; Optionally, t1+t2+t3=20-24s; Optionally, the t4 is 8-12s.

4. The method according to any one of claims 1 to 3, characterized in that The first preset pressure value is 110-115 kpa; and / or the second preset pressure value is 130-135 kpa.

5. The method according to any one of claims 1 to 3, characterized in that: The preset current is 355-365A.

6. The method according to any one of claims 1 to 3, characterized in that The pre-activation preparation process comprises: 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° C.; Optionally, the preset current density is 0.8-1.3A / m 2 .

7. The method according to claim 6, characterized in that The pre-activation preparation step also includes: Check whether the fuel cell system meets the requirements for entering the activation state. If the test is qualified, the online activation process is entered; otherwise, the fuel cell system issues an error shutdown command.

8. The method according to claim 7, characterized in that If the voltage of any battery in the fuel cell stack is lower than a preset voltage value, the fuel cell system issues the error shutdown instruction; Optionally, the preset voltage value is 0.2-0.4V.

9. A fuel cell system online activation device, characterized in that: It includes an air compressor, an intercooler, a humidifier and a battery stack connected in sequence; The humidifier is provided with a humidity regulating device and the humidity regulating device is connected to the humidifier; the fuel cell stack is provided with a radiator and a DC / DC converter, the radiator is used for auxiliary thermal management of the fuel cell stack, and the DC / DC converter converts the voltage and current of the fuel cell stack for output; the fuel cell stack is also provided with a hydrogen source, and the hydrogen source is connected to the fuel cell stack hydrogen circulation pipeline to assist hydrogen circulation, and a first pressure sensor and a regulating valve are arranged on the hydrogen circulation pipeline, the first pressure sensor is used to monitor the hydrogen pressure value on the hydrogen circulation pipeline, and the regulating valve is used to adjust the amount of hydrogen entering the fuel cell stack.

10. The device according to claim 9, characterized in that It also includes a circulation pump, which is connected to the fuel cell stack and the hydrogen circulation pipeline and is used to circulate the unused hydrogen back to the fuel cell stack to continue to participate in the reaction; The circulation pump is also connected with a drainage pipeline and an exhaust pipeline.

Images