An on-line activation method and system for a vehicle fuel cell system

Abstract

The present application belongs to the technical field of vehicle fuel cell, and particularly relates to an online activation method and system for a vehicle fuel cell system. The method comprises the following steps: when the cumulative running time of the vehicle fuel cell system reaches a set cumulative running time node, the fuel cell is passively activated before the last time when the fuel cell is allowed to be passively activated and powered off, and the passive activation time is less than or equal to the difference between the maximum delay power-off time of the vehicle and the normal power-off time. The passive activation with short time, low intensity and high frequency divides the original long-time fuel cell activation into fragmented time, which can ensure the performance of the fuel cell without affecting the power-off of the vehicle, and will not affect the normal use of the fuel cell due to long activation time, and improves the service life of the fuel cell.

Description

Technical Field

[0001] This invention belongs to the field of automotive fuel cell technology, specifically relating to an online activation method and system for an automotive fuel cell system. Background Technology

[0002] During operation, fuel cells inevitably experience performance degradation, necessitating activation to enhance their performance. Current activation methods mostly rely on offline activation during maintenance to restore fuel cell performance. However, this approach requires on-site operation by after-sales and maintenance personnel, resulting in low efficiency and high labor costs.

[0003] To address this issue, existing technologies have proposed online activation methods for fuel cells. These methods can activate the fuel cell during its use, only requiring activation when maintenance is no longer needed, and eliminating the need for manual operation by after-sales and maintenance personnel, thus improving activation efficiency and reducing costs. However, to ensure the effectiveness of fuel cell activation, online activation often takes a long time per cycle, which can affect the normal operation of the fuel cell system and consequently the normal operation of fuel cell vehicles. Furthermore, this prolonged online activation can also reduce the lifespan of the fuel cell.

[0004] To address the technical problem of long activation time for fuel cells affecting normal operation, Chinese invention patent CN113571740B proposes a solution that determines whether activation is necessary based on the difference between the current and previous startup times of the fuel cell, as well as ambient humidity. This solution avoids the problem of activation affecting normal operation by prioritizing the activation step at startup. However, this solution does not shorten the activation time; it merely moves the activation step forward and fails to truly solve the problem of long activation time per cycle. Summary of the Invention

[0005] The purpose of this invention is to provide an online activation method and system for a vehicle fuel cell system, in order to solve the technical problem that the activation time of a single fuel cell system is long in the prior art, which affects the normal use and lifespan of the fuel cell.

[0006] To address the aforementioned technical problems, this invention provides an online activation method for a vehicle fuel cell system, comprising the following steps:

[0007] When the cumulative operating time of the vehicle fuel cell system reaches the set cumulative operating time node, the fuel cell is passively activated before the most recent power-down shutdown that allows passive activation of the fuel cell. The passive activation time is less than or equal to the difference between the vehicle's maximum delayed power-down time and the time required for normal power-down.

[0008] Furthermore, the passive activation employs constant-pressure cyclic activation, constant-current cyclic activation, or constant-operating-condition cyclic activation.

[0009] During the constant pressure cyclic activation process, the average single cell voltage of the fuel cell is equal to the set average single cell voltage threshold, which is the average single cell voltage with good activation effect determined by experiments.

[0010] During the constant operating condition cyclic activation process, constant current cycle and constant voltage cycle are performed alternately. Under constant voltage cycle, the average single cell voltage of the fuel cell is made equal to the set average single cell voltage threshold by adjusting the fuel cell operating current.

[0011] Operating conditions include fuel cell hydrogen path pressure, air path flow rate, and air path pressure.

[0012] Furthermore, when all conditions for allowing passive activation of the fuel cell are met, the vehicle is deemed to allow passive activation of the fuel cell. All conditions for allowing passive activation of the fuel cell include: the allowable operating power of the fuel cell and the maximum allowable charging power of the power battery are both greater than the set passive activation power, which is the activation power with good activation effect calibrated through experiments.

[0013] Furthermore, the fuel cell system is pre-treated before passive activation. The pre-treatment process includes: running the fuel cell at a set passive activation power for a first set time, wherein the set passive activation power is the activation power with good activation effect calibrated through experiments.

[0014] Furthermore, it also includes the following steps: when the degradation rate of the vehicle fuel cell is greater than a set degradation rate threshold, and the vehicle allows the fuel cell to be actively activated, the fuel cell is actively activated.

[0015] Furthermore, the active activation includes constant current cyclic activation.

[0016] Furthermore, the active activation also includes pre-activation, the pre-activation process of which includes controlling the fuel cell to gradually decrease from rated power to idle power and then increase back to rated power at set time intervals and set power differences.

[0017] Furthermore, before the constant current cycle activation of active activation, the fuel cell system is pre-treated. The pre-treatment process includes: running the fuel cell at a set active activation power for a second set time, wherein the set active activation power is the activation power with good activation effect calibrated through experiments.

[0018] Furthermore, when all the conditions for allowing the fuel cell to be actively activated are met, the vehicle is determined to allow the fuel cell to be actively activated. The conditions for allowing the fuel cell to be actively activated include: the current SOC of the power battery minus the vehicle demand SOC during the active activation process, and then minus the SOC increased by the fuel cell power generation during the active activation process. The result is within the range allowed by the power battery SOC.

[0019] Furthermore, the set cumulative running time nodes include integer multiples of the set cumulative running time.

[0020] Furthermore, active activation can be performed at most once within a set period.

[0021] Furthermore, after active activation, if the degradation rate of the vehicle fuel cell in the next set cycle is still greater than the set degradation rate threshold, active activation will be repeated. When the number of repeated executions exceeds the set number of repeated executions threshold, active activation will no longer be performed and an alarm will be triggered.

[0022] This invention is an improved invention, and its beneficial effects are as follows: The online activation method for vehicle fuel cell systems of this invention, whenever the cumulative operating time of the vehicle fuel cell system reaches a set cumulative operating time node, and the fuel cell performance slightly decreases, passive activation is performed before the next power-off activation, thereby improving fuel cell performance before power-off. Through short-duration, low-intensity, high-frequency passive activation, the originally concentrated and long-duration fuel cell activation is divided into fragmented time periods. The time of each passive activation is less than or equal to the difference between the vehicle's maximum delayed power-off time and the time required for normal power-off, without affecting the vehicle's power-off. This ensures the performance of the fuel cell without affecting its normal use due to the long activation time, and at the same time improves the service life of the fuel cell.

[0023] To address the aforementioned technical problems, the present invention also provides an online activation system for a vehicle fuel cell system, comprising a processor, wherein the processor, when executing a computer program, implements the steps described in the online activation method for a vehicle fuel cell system of the present invention.

[0024] This invention is an improved invention, and its beneficial effects are the same as those of the online activation method for vehicle fuel cell systems of this invention. Attached Figure Description

[0025] Figure 1 This is a flowchart of the passive activation process in an embodiment of the method of the present invention;

[0026] Figure 2 This is a flowchart of the active activation process in an embodiment of the method of the present invention;

[0027] Figure 3 This is a schematic diagram of the system configuration of an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of passive activation under constant pressure cyclic activation in an embodiment of the method of the present invention;

[0029] Figure 5 This is a schematic diagram of passive activation under constant working conditions cyclic activation in an embodiment of the method of the present invention;

[0030] Figure 6 This is a schematic diagram of active activation constant current cyclic activation in an embodiment of the method of the present invention. Detailed Implementation

[0031] This invention discloses an online activation method and system for a vehicle fuel cell system. Whenever the cumulative operating time of the vehicle's fuel cell system reaches a set cumulative operating time node, and the fuel cell performance slightly decreases, a passive activation is performed before the next power-off activation. This improves the fuel cell performance before power-off. By performing short-duration, low-intensity, high-frequency passive activation, the originally concentrated and long-duration fuel cell activation is divided into fragmented time periods. The time of each passive activation is less than or equal to the difference between the vehicle's maximum delayed power-off time and the time required for normal power-off, without affecting the vehicle's power-off. This ensures the performance of the fuel cell without affecting its normal use due to the long activation time, and at the same time improves the service life of the fuel cell.

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] Example of an online activation method for a vehicle fuel cell system:

[0034] The online activation method for the vehicle fuel cell system of the present invention is divided into active activation (hereinafter also referred to as enhanced activation) and passive activation (hereinafter also referred to as shutdown activation). Passive activation is the low-power discharge activation performed by the fuel cell system after it has reached a certain cumulative running time and before the next power-off of the vehicle. Active activation is the active high-power discharge activation of the fuel cell system by issuing an instruction during driving after an abnormality in the performance of the fuel cell is detected during normal vehicle operation.

[0035] In this embodiment, the passive activation process is as follows: Figure 1 As shown, it includes the following steps:

[0036] Step 1: The vehicle control unit (VCU) determines the cumulative runtime of the fuel cell system and decides whether the fuel cell system needs to be shut down and activated based on the cumulative runtime.

[0037] In this embodiment, when the cumulative operating time of the fuel cell reaches a set cumulative operating time node, the shutdown activation signal of the fuel cell system is set to 1, indicating that the fuel cell needs to be activated before power-off. In this embodiment, setting the cumulative operating time node includes setting an integer multiple of the cumulative operating time interval. For example, if the cumulative operating time is set to 10 hours, the set cumulative operating time nodes include 10 hours, 20 hours, 30 hours, etc. As another implementation, a node that is not an integer multiple of the set cumulative operating time can also be set according to actual needs, such as 35 hours. The set cumulative operating time can be a fixed value or a variable value. For example, when the cumulative operating time of the fuel cell is short, the fuel cell decays slowly, so the set cumulative operating time can be larger, such as 10 hours; as the cumulative operating time increases, the fuel cell decays faster, so the set cumulative operating time can be reduced accordingly, for example, reduced to 5 hours.

[0038] Step 2: With the fuel cell in operation, during the most recent vehicle power-off, determine whether the fuel cell is allowed to be activated by shutdown. If allowed, proceed to Step 3; otherwise, repeat Step 2 the next time the vehicle power-off occurs.

[0039] When all conditions for passive activation of the fuel cell are met, the vehicle is deemed to allow passive activation of the fuel cell. In this embodiment, the conditions for allowing passive activation of the fuel cell include: the fuel cell system temperature is normal, the allowable operating power of the fuel cell and the maximum allowable charging power of the power battery are both greater than the set passive activation power.

[0040] In this embodiment, the specific method for determining whether the fuel cell can be activated after shutdown is as follows: First, the temperature of the fuel cell system is determined. If the temperature of the fuel cell system is greater than or equal to the set normal lower limit T, min And less than or equal to the set normal temperature upper limit T max Then, it is further determined whether the smaller of the allowed working power of the fuel cell system and the maximum allowed charging power of the power battery is greater than the set shutdown activation power (set passive activation power). If it is greater, it is determined that the fuel cell can be shut down and activated, and the subsequent shutdown activation steps are carried out.

[0041] The smaller of the fuel cell system's permissible operating power and the maximum permissible charging power of the power battery is greater than the set shutdown activation power. This indicates that both values ​​are greater than the shutdown activation power. The fuel cell system's permissible operating power exceeding the set shutdown activation power ensures that the fuel cell can perform shutdown activation. The power battery's maximum permissible charging power exceeding the set shutdown activation power means that the electricity generated during shutdown activation can be charged into the power battery. At this point, the vehicle is in a state of impending power-off shutdown, therefore the vehicle's power demand is close to zero, and all the electricity generated during fuel cell shutdown activation is used to charge the power battery.

[0042] If the fuel cell system temperature is abnormal, or if at least one of the fuel cell system's allowed operating power and the power battery's allowed maximum charging power is less than or equal to the shutdown activation power, the fuel cell is determined to be unable to perform shutdown activation, and the shutdown activation signal is retained as 1. The determination will be made again the next time the vehicle is powered off.

[0043] Step 3: Pre-treat the fuel cell system.

[0044] The fuel cell is operated in constant current mode for a first set time (T1 in the figure) according to the set passive activation power. The set passive activation power is the activation power with good activation effect calibrated by experiments.

[0045] Step 4: Power off and activate the fuel cell system.

[0046] In this embodiment, the fuel cell system is activated by constant pressure cycling, and the average single-cell voltage of the fuel cell is controlled to a set average single-cell voltage threshold. In this embodiment, the average single-cell voltage threshold is set to be greater than or equal to 0.45V to ensure that the fuel cell will not reverse polarity due to excessive current. The operating conditions of the fuel cell system are periodically adjusted, including hydrogen path pressure, air path flow rate, and air path pressure, with a periodic change of decreasing value - normal value - decreasing value. The shutdown activation power, the decreasing value of operating conditions, the duration of the decreasing value, and the duration of the normal value are calibrated in advance based on experimental results.

[0047] The changes in the operating voltage, operating current, and operating conditions of the fuel cell system during the activation process are as follows: Figure 5 As shown. When switching from constant current mode to constant voltage mode, the fuel cell DC / DC converter first draws in the current to control the fuel cell to operate at an average voltage of 0.45V. Then, the fuel cell controller controls the operating conditions to decrease to a calibrated fixed value, and the fuel cell DC / DC converter automatically controls the current of the fuel cell to decrease, maintaining the average voltage at 0.45V.

[0048] As another implementation method, the shutdown activation of the fuel cell system can also employ constant current activation or constant operating condition cyclic activation. The constant operating condition cyclic activation method is as follows:

[0049] To maintain normal operating conditions, the fuel cell alternates between constant-voltage activation and constant-current activation modes. In constant-current mode, it operates normally at the activation power. Upon switching to constant-voltage mode, the fuel cell's DC / DC converter actively draws current to maintain the average voltage at 0.45V. The changes in fuel cell operating voltage, operating current, and operating conditions during this process are as follows: Figure 4 As shown.

[0050] Step 4: Complete discharge activation and power off the fuel cell.

[0051] First, it checks if the current operating current is greater than or equal to the maximum operating current, or less than or equal to the idle current. If so, the constant-pressure cycle activation ends. Otherwise, it checks if the cycle period has reached the set cycle period n1. If so, the constant-pressure cycle activation ends; otherwise, the cycle repeats and the above two termination conditions are checked repeatedly. When the cycle period reaches the set cycle period n1, the fuel cell system performs a shutdown operation, the fuel cell undergoes normal purging, and the vehicle is powered off with a delayed shutdown. The set cycle period n1 is determined by the vehicle's longest delayed shutdown time and the fuel cell shutdown duration, where shutdown activation time T2 + normal shutdown time T3 ≤ vehicle's longest delayed shutdown time.

[0052] Through the above steps, the fuel cell system activation method of the present invention activates the fuel cell before powering off when the fuel cell is powered down after the cumulative operating time of the fuel cell increases by a set time. The power of each activation is low. This low-intensity, high-frequency fuel cell activation strategy can slow down the oxidation of the fuel cell catalyst and improve the life of the fuel cell.

[0053] In this embodiment, the method for active activation (also known as enhanced activation) of the fuel cell system is as follows: Figure 2 As shown, it includes the following steps:

[0054] Step 1: Obtain operating data of the fuel cell system, including operating current, voltage, and reaction conditions.

[0055] Step 2: Analyze the performance changes of the fuel cell system based on the acquired operating data. When the degradation rate exceeds the set degradation rate threshold, send a request for enhanced activation to the vehicle controller via the vehicle network.

[0056] Step 3: When the vehicle controller receives the enhanced activation request, it sets the enhanced activation signal to 1, indicating that the fuel cell system needs enhanced activation. It then determines whether the vehicle allows the fuel cell to undergo enhanced activation.

[0057] When all conditions for active activation of the fuel cell are met, the vehicle is deemed to allow active activation of the fuel cell. In this embodiment, the conditions for active activation of the fuel cell include: normal fuel cell temperature, the allowable charging power of the power battery exceeding the set active activation power, and the current state of charge (SOC) of the power battery allowing for enhanced activation.

[0058] In this embodiment, the specific process for determining whether the vehicle allows the fuel cell to undergo enhanced activation includes:

[0059] 3.1 First, determine if the fuel cell is operating normally. Check if the fuel cell temperature is greater than or equal to the set lower limit of the normal temperature range and if the charging power of the power battery is greater than the set active activation power. If both are true, further determine if the current SOC of the power battery allows the fuel cell to undergo enhanced activation. If the result is yes, proceed to the next step to enhance the activation of the fuel cell. Otherwise, determine that the fuel cell system does not allow enhanced activation.

[0060] 3.2 Determine whether the current SOC of the power battery allows for enhanced activation.

[0061] If the difference between the current SOC of the power battery and the total energy demand of the vehicle during active activation divided by the total energy of the fuel cell, and the difference between the current SOC of the power battery and the energy generated by the fuel cell during active activation divided by the total energy of the power battery, is within the allowable range of the power battery's SOC, then the current SOC of the power battery is deemed to allow active activation; otherwise, the current SOC of the power battery is deemed not to allow enhanced activation.

[0062] In this embodiment, active activation includes constant current cycle activation and pre-activation. Therefore, the fuel cell power generation during active activation includes the power generation from constant current cycle activation and the power generation from pre-activation. The vehicle's power demand during active activation includes the power demand from pre-activation and the power demand from constant current cycle activation. Specifically, the method for determining whether the current SOC of the power battery allows for enhanced fuel cell activation is as follows: The calculated SOC is calculated as follows: current SOC of the vehicle's power battery - estimated vehicle power consumption during pre-activation and constant current cycle activation / total power battery capacity (representing the SOC consumed by the vehicle) - total power generation during pre-activation and constant current cycle activation / total power battery capacity (increased SOC due to activation). This yields an estimated SOC after enhanced activation. If this SOC value is within the allowable range for the fuel cell, then the vehicle's power battery SOC value is determined to allow for enhanced fuel cell system activation. Estimated vehicle power consumption during pre-activation and constant current cycle activation = average vehicle power demand × (pre-treatment time T4 + enhanced activation time T5). Total power generation during pre-activation and constant current cycle activation = pre-treatment fuel cell power generation + enhanced activation fuel cell power generation.

[0063] If the result of 3.1 is that enhanced activation is not allowed, the vehicle will operate normally without enhanced activation; if the result of 3.2 is that enhanced activation is not allowed, the pre-activation strategy will be adjusted and step 3.2 will be executed again.

[0064] Step 4: Before performing constant current cycle activation of the fuel cell, pre-activate the fuel cell system.

[0065] The pre-activation process includes: the vehicle controller sending target power (various power levels decreasing from rated power to idle power according to a set power difference) to the fuel cell system, and then gradually decreasing from rated power to idle power and then gradually increasing back to rated power at set time intervals. The duration of each target power and the interval between power levels can be adjusted according to experimental conditions to fully wet the fuel cell and improve the pre-activation effect.

[0066] As the optimal implementation method, this embodiment improves the activation effect through pre-activation. At the same time, the SOC of the power battery can be adjusted by adjusting the target power of pre-activation, so as to allow the SOC of the power battery to undergo enhanced activation.

[0067] Step 5: Perform pretreatment before constant current cycling activation.

[0068] The pretreatment process includes: controlling the fuel cell system to run for a second set time (T6 in the figure) according to the set active activation power. The set active activation power is the activation power with good activation effect determined through experiments. In this embodiment, the active activation power is set to be equal to the rated power.

[0069] Step Six: Perform constant current cyclic activation on the fuel cell. During the constant current cyclic activation process, the average single-cell voltage protection value is set to a set average single-cell voltage threshold of 0.45V, and the lowest single-cell voltage is greater than or equal to the set lowest single-cell voltage threshold of 0.1V. The operating conditions of the fuel cell system are periodically adjusted to exhibit a periodic change of decreasing-normal-decreasing. The operating conditions of the fuel cell system include hydrogen path pressure, air path flow rate, and air path pressure. During the periodic change, the decreasing time and normal duration of one cycle are calibrated based on experimental conditions.

[0070] The specific activation process is as follows: Figure 6 As shown, under rated current, the operating conditions controlled by the fuel cell controller decrease, and the voltage of the fuel cell decreases accordingly. When it drops to the calibrated 0.45V, it remains unchanged. During this process, if the voltage continues to drop, the operating conditions are increased to maintain the average voltage at 0.45V. After maintaining this for a certain period of time, the operating conditions are adjusted to normal operating conditions, and the corresponding cyclic operation continues.

[0071] In this embodiment, the decline in the operating conditions of the fuel cell is pre-calibrated. In other implementations, PI regulation can also be used to control it, thereby ensuring that the average cell voltage is not lower than the set average cell voltage threshold.

[0072] Step 7: End Constant Current Cyclic Activation. During the cycle, first determine if the average single-cell voltage is less than the set average single-cell voltage threshold of 0.45V. If it is less, end the constant current cycle activation directly. Otherwise, determine if the current cycle number is greater than or equal to the set second cycle number n2. If yes, end the constant current cycle activation. Otherwise, proceed to the next cycle and re-determine whether to end the constant current cycle activation. After ending the constant current cycle activation, the vehicle controller sends a normal operation command to the fuel cell system, and the fuel cell system operates according to the normal energy management strategy of the fuel cell system. At the same time, set the enhanced activation to 0 and the enhanced activation count to 1.

[0073] To avoid repeated enhanced activation, which increases hydrogen consumption and affects the normal operation of the fuel cell, this embodiment limits enhanced activation to a maximum of once within a set cycle; in this embodiment, the set cycle is one day. Therefore, once the enhanced activation signal count reaches 1, the enhanced activation operation will not be performed again that day. On the second day, the vehicle controller checks the enhanced activation signal again. If the enhanced activation signal is 1, the enhanced activation operation is repeated, and the number of repeated enhanced activations is recorded. If the number of repeated enhanced activations exceeds the set threshold and the enhanced activation signal still exists, after-sales maintenance personnel are alerted to go to the site for handling.

[0074] When the fuel cell is not allowed to undergo enhanced activation, the enhanced activation information is retained as 1, and the enhanced activation operation will be performed again when the conditions are met.

[0075] In this embodiment, when a vehicle network warning signal is received again on the third day, the attenuation rate fault is pushed to after-sales service, reminding after-sales maintenance personnel to go to the site for handling. If no warning occurs for a set number of consecutive days, the number of enhanced activation counts is reset to zero.

[0076] Example of an online activation system for automotive fuel cell systems:

[0077] An online activation system for a vehicle fuel cell system according to the present invention, such as Figure 3As shown, the system includes a big data platform. This platform connects the vehicle's fuel cell controller and the vehicle controller via a vehicle network (in this embodiment, a vehicle ICARD). It obtains vehicle fuel cell system operation data from the fuel cell controller, determines whether the fuel cell is malfunctioning based on this data, and sends a warning to the vehicle controller when an malfunction occurs. This prompts the vehicle controller to send an active activation strategy to the fuel cell controller (in this embodiment, this includes a set passive activation power for passive activation, a set time interval and power difference for pre-activation, and a set active activation power for active activation). The fuel cell controller, including a processor, executes the computer program to perform both passive and active activation of the fuel cell, aiming to restore the fuel cell system's performance as much as possible through passive activation and minimize active activation. The specific process, principle, and beneficial effects of this method have been described in detail in the method embodiments and will not be repeated here.

[0078] In this embodiment, the fuel cell system activation system also includes a gas pump on the hydrogen supply line and a gas pump on the oxygen supply line of the fuel cell. By periodically changing the speed of the gas pumps on the hydrogen supply line and the oxygen supply line, the operation of the fuel cell is periodically adjusted, thereby achieving constant pressure cycle adjustment and constant flow cycle adjustment.

[0079] When the big data platform detects abnormal fuel cell degradation, it sends a request for enhanced activation to the VCU via the vehicle's ICARD. The VCU then assesses the vehicle's operating status, proactively plans the target power for the fuel cell, and initiates enhanced activation after reaching the appropriate SOC and fuel cell operating temperature, accelerating the recovery of fuel cell performance. For engines where fuel cell performance does not improve after activation, after-sales service is notified for on-site maintenance, improving the timeliness of problem handling and reducing after-sales costs. Through both active and passive online activation, the lifespan of the fuel cell is maximized, after-sales maintenance costs are reduced, and the impact of activation on vehicle operation is avoided. Specific methods and principles for enhanced activation are described in the method implementation examples.

[0080] In summary, the online activation method and system for a vehicle fuel cell system of the present invention can perform passive activation after the fuel cell system has accumulated a set cumulative operating time node. Passive activation is characterized by low power during a short period of time. Under the condition that conditions permit, it can be completed before the vehicle is powered off, without affecting the normal operation of the vehicle. Furthermore, the performance of the fuel cell can be guaranteed by high-frequency, short-duration, low-power activation, while avoiding the reduction in the service life of the fuel cell caused by long activation.

[0081] Furthermore, the present invention can also monitor the degradation of the fuel cell in real time. When the degradation rate of the fuel cell exceeds the set degradation rate threshold, it can still perform high-power, long-term active activation to ensure the performance of the fuel cell.

[0082] Furthermore, the active activation of this invention employs constant-pressure cyclic activation, which features good activation effect, short activation time, and low hydrogen consumption. Furthermore, to ensure the effectiveness of constant-pressure cyclic activation, the average single-cell voltage during the constant-pressure activation process is set to a predetermined average single-cell voltage threshold. This voltage is experimentally calibrated to achieve a good activation effect, further enhancing the activation effect while preventing excessive current and reverse polarity.

Claims

1. A method for online activation of a vehicle fuel cell system, characterized in that, Includes the following steps: When the cumulative operating time of the vehicle fuel cell system reaches the set cumulative operating time node, the fuel cell is passively activated before the most recent power-down shutdown that allows passive activation of the fuel cell. The passive activation time is less than or equal to the difference between the vehicle's maximum delayed power-down time and the time required for normal power-down.

2. The online activation method for a vehicle fuel cell system according to claim 1, characterized in that, The passive activation is performed by constant pressure cyclic activation, constant current cyclic activation, or constant working condition cyclic activation. During the constant pressure cyclic activation process, the average single cell voltage of the fuel cell is equal to the set average single cell voltage threshold, which is the average single cell voltage with good activation effect determined by experiments. During the constant operating condition cyclic activation process, constant current cycle and constant voltage cycle are performed alternately. Under constant voltage cycle, the average single cell voltage of the fuel cell is made equal to the set average single cell voltage threshold by adjusting the fuel cell operating current. Operating conditions include fuel cell hydrogen path pressure, air path flow rate, and air path pressure.

3. The online activation method for a vehicle fuel cell system according to claim 1, characterized in that, When all conditions for passive activation of the fuel cell are met, the vehicle is deemed to allow passive activation of the fuel cell. All conditions for passive activation of the fuel cell include: the allowable operating power of the fuel cell and the maximum allowable charging power of the power battery are both greater than the set passive activation power. The set passive activation power is the activation power with good activation effect calibrated through experiments.

4. The online activation method for a vehicle fuel cell system according to claim 1, characterized in that, Before passive activation, the fuel cell system is pre-treated. The pre-treatment process includes running the fuel cell at a set passive activation power for a first set time. The set passive activation power is the activation power with good activation effect calibrated through experiments.

5. The online activation method for a vehicle fuel cell system according to claim 1, characterized in that, It also includes the following steps: When the degradation rate of the vehicle fuel cell exceeds a set degradation rate threshold, and the vehicle allows the fuel cell to be actively activated, the fuel cell is actively activated.

6. The online activation method for a vehicle fuel cell system according to claim 5, characterized in that, The active activation includes constant current cyclic activation.

7. The online activation method for a vehicle fuel cell system according to claim 6, characterized in that, The active activation also includes pre-activation, and the pre-activation process includes: controlling the fuel cell to gradually decrease from the rated power to the idle power and then increase back to the rated power at a set time interval and a set power difference.

8. The online activation method for a vehicle fuel cell system according to claim 6, characterized in that, Before the constant current cycle activation of active activation, the fuel cell system is pre-treated. The pre-treatment process includes: running the fuel cell at a set active activation power for a second set time. The set active activation power is the activation power with good activation effect calibrated through experiments.

9. The online activation method for a vehicle fuel cell system according to claim 6, characterized in that, When all the conditions for active activation of the fuel cell are met, the vehicle is deemed to be allowed to actively activate the fuel cell. The conditions for active activation of the fuel cell include: the current SOC of the power battery minus the vehicle demand SOC during the active activation process, and then minus the SOC increased by the fuel cell power generation during the active activation process. The result is within the range allowed by the power battery SOC.

10. The online activation method for a vehicle fuel cell system according to any one of claims 1-9, characterized in that, The set cumulative running time nodes include integer multiples of the set cumulative running time.

11. The online activation method for a vehicle fuel cell system according to claim 10, characterized in that, After active activation is performed, if the degradation rate of the vehicle fuel cell in the next set cycle is still greater than the set degradation rate threshold, active activation will be repeated. When the number of repeated executions exceeds the set number of repeated executions threshold, active activation will no longer be performed and an alarm will be triggered.

12. An online activation system for a vehicle fuel cell system, comprising a processor, characterized in that, When the processor executes a computer program, it implements the steps of the online activation method for a vehicle fuel cell system as described in any one of claims 1-11.

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