A method, system, device and computer program for purging control of a fuel cell

Abstract

The present application relates to the technical field of fuel cell purging, and discloses a purging control method, system, device and computer for a fuel cell, which comprises the following steps: when the FCU receives a shutdown instruction of the fuel cell system, it is detected whether cold purging is needed; if the fuel cell system needs cold purging, cold purging is performed based on a preset cold purging strategy after the stack temperature is confirmed; and if the fuel cell system does not need cold purging, normal-temperature purging is performed. Through the cooperation of self-heating and cold purging strategies, the present application realizes cold purging operation of the fuel cell system, the self-heating design can replace the function of an external heater in the prior art, which not only ensures the stack temperature rising function, but also reduces the complexity of the structure of the fuel cell system and the design difficulty of the stack, and meanwhile, the overall cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell purging technology, in particular to a fuel cell purging control method, system, device and computer. BACKGROUND

[0002] As an important technical route to achieve "carbon neutralization" and "carbon peak", fuel cell systems have been continuously innovated in recent years under the policy of the country's vigorous promotion. With the policy landing of "demonstration operation" cities, proton exchange membrane fuel cells have ushered in an important opportunity for industry development. Proton exchange membrane fuel cells convert hydrogen energy into electrical energy through electrochemical reactions, and produce liquid water at the same time. In early winter, when the engine is not working, to avoid excessive freezing of liquid water in the system and cause reliability problems such as MEA and membrane humidifier failure, the system must be purged before shutdown in low temperature environment to ensure that the amount of water stored in the fuel cell system does not affect the service life and normal operation of the components.

[0003] However, with the increasing trend of fuel cell system power, most systems will integrate membrane humidifiers to ensure their operating life, but the integration of humidifiers will also increase the difficulty of purging. Generally, to achieve complete purging, the corresponding stack temperature during purging needs to be maintained. Due to the uncertainty of the use scenario and pre-shutdown working conditions, there may be a situation where the fuel cell stack temperature has not reached the target purging temperature at shutdown. If the purging temperature is too low, it may result in incomplete purging, which may cause excessive freezing of water in the fuel cell system and lead to reliability problems such as MEA and membrane humidifier failure.

[0004] The existing technology generally integrates an external heater on the fuel cell system. When the purging temperature is lower than the target temperature, the stack temperature can be raised by external heating to ensure complete purging. However, for fuel cell systems without external heating architecture, the stack is generally required to withstand multiple freeze-thaw cycles, which damages the service life of the stack. However, adding an external heater to the fuel cell system will make the structure of the fuel cell system more complex and the cost higher. The design of a low-temperature high-tolerance stack is also more difficult and the material cost is higher. SUMMARY

[0005] To solve the problem of the need to control the stack temperature during cold purging of the fuel cell system to achieve better purging effect, the present application provides a fuel cell purging control method, system, device and computer to solve the problem of inconvenient cold purging of the fuel cell or the need to increase additional costs.

[0006] The technical content of the present application is as follows:

[0007] A fuel cell purging control method, comprising the following steps:

[0008] When the FCU receives a fuel cell system shutdown instruction, it is detected whether cold purge is needed;

[0009] If the fuel cell system needs cold purge, the stack temperature is confirmed, and cold purge is performed based on a preset cold purge strategy;

[0010] If the fuel cell system does not need cold purge, normal temperature purge is performed.

[0011] Further, the stack temperature confirmation includes:

[0012] Determine whether the water temperature at the stack outlet is higher than the preset calibration temperature;

[0013] If yes, execute the preset cold purge strategy, and if no, enter the self-heating state until the water temperature at the stack outlet is higher than the preset calibration temperature, and then execute the preset cold purge strategy.

[0014] Further, the self-heating state includes reducing the cathode metering ratio and controlling the cooling liquid flow.

[0015] Further, the cathode metering ratio is determined by calibration of the stack current and stack voltage at different air metering ratios.

[0016] Further, the preset cold purge strategy includes increasing the air flow in the fuel cell system and monitoring the stack online impedance value.

[0017] Further, in the process of performing cold purge based on the preset cold purge strategy after confirming the stack temperature, the method further includes:

[0018] Determine whether the stack online impedance value is higher than the preset calibration impedance value;

[0019] If yes, stop cold purge, accept the fuel cell system shutdown instruction, and if no, continue cold purge.

[0020] Further, the detection of whether cold purge is needed includes: confirming whether cold purge is needed through temperature sensor monitoring information or cloud platform monitoring weather data.

[0021] According to the fuel cell purge control method of the embodiment, the present application provides a fuel cell purge control system, which includes:

[0022] The fuel cell control module is used to detect whether cold purge is needed when receiving a fuel cell system shutdown instruction;

[0023] The purge execution module is used to perform normal temperature purge or cold purge operation of the fuel cell system;

[0024] The shutdown module is used to perform shutdown after normal temperature purge or shutdown after determining that the stack online impedance value during cold purge is higher than the preset calibration impedance value.

[0025] According to the fuel cell purging control method of the embodiment, the present application provides a fuel cell purging control device, comprising:

[0026] a memory for storing a computer program;

[0027] a processor for executing the computer program to realize the steps of the fuel cell purging control method according to any one of the above embodiments.

[0028] According to the fuel cell purging control method of the embodiment, the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program, and the computer program is executed by a processor to realize the steps of the fuel cell purging control method according to any one of the above embodiments.

[0029] The present application has at least the following beneficial effects:

[0030] (1) The present application realizes fast heating of the fuel cell system without an external heater by regulating the cathode stoichiometric ratio, ensures that the cold purging operation can be completed even in the case that the fuel cell is low-temperature due to the pre-conditioning, and improves the reliability of the fuel cell system.

[0031] (2) The cold purging operation of the fuel cell system is realized by cooperation of the self-heating and cold purging strategies, the self-heating design can replace the function of the external heater in the prior art, ensures the stack temperature rising function, reduces the complexity of the structure of the fuel cell system and the design difficulty of the stack, and reduces the overall cost. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A flowchart of a fuel cell purging control method according to the embodiment 1 of the present application is shown.

[0033] Figure 2 A flowchart of a fuel cell purging control method without an external heater according to the embodiment 2 of the present application is shown.

[0034] Figure 3 A structure diagram of a fuel cell purging control device without an external heater according to the embodiment 3 of the present application is shown.

[0035] Wherein, 1-fuel cell stack; 2-ac impedance piece; 3-direct current power converter DCDC; 4-fuel cell controller FCU; 5-vehicle controller VCU; 6-temperature sensor; 7-thermostat; 8-water pump; 9-compensation water tank; 10-deionization tank; 11-radiator; 12-air filter; 13-flow meter; 14-air compressor; 15-intercooler; 16-electronic control three-way valve; 17-tail exhaust throttle; 18-humidifier; 19-hydrogen ejector; 20-ejector; 21-hydrogen inlet pressure sensor; 22-safety valve; 23-anode water distribution piece; 24-tail exhaust valve. DETAILED DESCRIPTION

[0036] To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] Embodiment 1

[0038] In combination with Figure 1 the drawings, the present embodiment provides a purging control method of a fuel cell, comprising the following steps:

[0039] When the FCU receives a shutdown instruction of the fuel cell system, it is detected whether cold purging is needed;

[0040] If the fuel cell system needs cold purging, cold purging is performed based on a preset cold purging strategy after the stack temperature is confirmed;

[0041] If the fuel cell system does not need cold purging, normal temperature purging is performed.

[0042] Further, the confirmation of the stack temperature comprises:

[0043] determining whether the water temperature at the outlet of the stack is higher than a preset calibration temperature;

[0044] If yes, the preset cold purging strategy is executed, and if no, a self-heating state is entered until the water temperature at the outlet of the stack is higher than the preset calibration temperature, and then the preset cold purging strategy is executed.

[0045] Further, the self-heating state comprises reducing the cathode metering ratio and controlling the flow of the cooling liquid.

[0046] Further, the cathode metering ratio is determined through calibration of the stack current and the stack voltage at different air metering ratios.

[0047] Furthermore, the preset cold purging strategy includes increasing the airflow rate within the fuel cell system and monitoring the online impedance value of the fuel cell stack.

[0048] Furthermore, during the cold purging process based on a preset cold purging strategy after confirming the reactor temperature, the method further includes:

[0049] Determine whether the online impedance value of the fuel cell stack is higher than the preset calibration impedance value;

[0050] If yes, stop the cold purging and accept the fuel cell system shutdown command; otherwise, continue the cold purging.

[0051] Furthermore, the detection of whether a cold purging is required includes: confirming whether a cold purging is required by monitoring information from a temperature sensor or by monitoring weather data through a cloud platform.

[0052] Example 2

[0053] According to Example 1 and Figure 2 As shown, this embodiment provides a purging control method for a fuel cell without an external heater, including the following steps:

[0054] First, when the fuel cell system is powered on, it will automatically check whether the communication of each subsystem and the in-situ values ​​of each monitoring sensor are normal. Then, according to the host computer or user requirements, the FCU controls the DC-DC converter to apply current according to the standard PI curve calibrated during system design.

[0055] Secondly, the FCU performs a load reduction and shutdown operation based on the received instructions. Generally, it controls the DC-DC converter to unload the current and simultaneously controls the hydrogen-air-water circuit components to respond to the flow and pressure requirements under the corresponding current. While unloading, the FCU determines whether the fuel cell system needs to be cold-purged by using the ambient temperature sensor or the date and weather information released by the data cloud platform.

[0056] If the judgment result does not require cold purging, that is, the ambient temperature and weather information show that the air temperature will be above 0 degrees, room temperature purging can be performed. Room temperature purging generally only needs to remove water stored in the internal flow channels of the fuel cell stack. Therefore, low frequency impedance is used as the exit condition for this step. If there is no online AC impedance, the fixed purging time can also be used as the exit condition for this step. After purging is completed, the machine is turned off.

[0057] If the assessment results indicate that cold purging is required, then the fuel cell stack outlet water temperature T should be further determined. out Is it higher than the preset calibration temperature T? set If yes, execute the preset cold purging strategy; otherwise, enter the self-heating state until the fuel cell outlet water temperature is higher than the preset calibration temperature, then execute the preset cold purging strategy.

[0058] The self-heating state includes reducing the cathode stoichiometry λ, i.e. obtaining a lower overall voltage value V at a set current I, aiming to reduce the fuel cell stack electrical efficiency and improve the corresponding thermal efficiency, and simultaneously controlling the coolant flow rate, i.e. controlling the small circulation coolant flow rate of the cooling circuit to realize rapid warm-up of the stack until the stack temperature reaches T set .

[0059] The cathode stoichiometry is determined by calibration of the stack current and stack voltage at different air stoichiometries, i.e. calibration at a set current I and an overall voltage value V, and the corresponding overall voltage value V can be determined according to the following formula:

[0060]

[0061] where t is the design heating time, in seconds, and N is the number of stack pieces;

[0062] dQ / dT is the small circulation overall heat capacity of the system, which can be calculated by material or actually tested and calibrated;

[0063] T is the actual stack temperature; V is the overall voltage, in V; and I is the load current.

[0064] When the cold purge strategy is executed, i.e. the air flow rate is increased for forced purging, the on-line impedance R value of the entire stack is monitored.

[0065] Finally, it is determined whether the on-line impedance value R of the stack is higher than the preset calibration impedance value R set ;

[0066] If yes, after stopping the cold purging, the shutdown instruction of the fuel cell system is accepted, and if no, the cold purging is continued.

[0067] R set is the low-temperature shutdown requirement value, which can be changed according to different environmental temperature requirements, aiming to ensure that the cold purging is completed but not excessively purged, and further improve the reliability and service life of the fuel cell system.

[0068] The present embodiment can be adapted to energy storage devices, and simultaneously start two or more units, thereby comprehensively reducing the demand for energy storage devices and quickly responding to the demand.

[0069] Embodiment 3

[0070] According to Embodiment 2 in combination with Figure 3 , the present embodiment provides a purging control device for a fuel cell without an external heater, comprising:

[0071] a fuel cell stack (1),

[0072] an alternating current impedance element (2) arranged on the fuel cell stack (1);

[0073] a direct current power converter DCDC (3) connected with the fuel cell stack (1);

[0074] a fuel cell controller FCU (4) connected with the direct current power converter DCDC (3);

[0075] a vehicle controller VCU (5) for inputting demand power to the FCU (4);

[0076] a hydrogen subsystem, an air subsystem and a cooling subsystem, all connected with the fuel cell stack (1);

[0077] wherein the FCU (4) controls the fuel cell system to perform normal-temperature purging or cold purging after monitoring that the stack temperature is greater than a preset stack temperature;

[0078] the alternating current impedance element (2) is used to obtain an online impedance value of the fuel cell stack (1), and the fuel cell system judges whether purging is completed through the online impedance value.

[0079] Further, the device further comprises a heating circulation system connected with the fuel cell stack (1) to form a heating loop, wherein the heating circulation system comprises a thermostat (7) and a water pump (8), and the fuel cell stack (1) controls the flow of cooling liquid in the circulation loop through the heating circulation system and the FCU reduces the cathode stoichiometric ratio of the fuel cell stack (1) to increase the stack temperature.

[0080] Further, temperature sensors (6) are arranged on the inlet and outlet ends of the cooling liquid of the fuel cell stack (1).

[0081] Further, the same humidifier (18) is connected to the air inlet and outlet ends of the fuel cell stack (1).

[0082] Further, the air subsystem comprises an air filter (12), a flow meter (13), an air compressor (14), an intercooler (15), an electrically-controlled three-way valve (16) and a tail exhaust throttle valve (17), wherein the air filter (12), the flow meter (13), the air compressor (14), the intercooler (15) and the electrically-controlled three-way valve (16) are connected in sequence, the electrically-controlled three-way valve (16) is connected with the fuel cell stack (1) through the humidifier (18), the tail exhaust throttle valve (17) is arranged at the air outlet end of the fuel cell stack (1), and the fuel cell stack (1) is connected with the tail exhaust throttle valve (17) through the humidifier (18).

[0083] Further, the hydrogen subsystem comprises a hydrogen injector (19), an ejector (20), an inlet hydrogen pressure sensor (21), a safety valve (22), an anode water distribution device (23), and a tail valve (24), the hydrogen injector (19), the ejector (20), the inlet hydrogen pressure sensor (21), the safety valve (22), the fuel cell stack (1), the anode water distribution device (23), and the tail valve (24) are sequentially connected, and the anode water distribution device (23) is connected with the ejector (20).

[0084] Further, the cooling subsystem comprises a radiator (11), a deionization tank (10), and a compensation water tank (9), two ends of the radiator (11) are respectively connected with the fuel cell stack (1) cooling liquid inlet and outlet ends, two ends of the deionization tank (10) are respectively connected with the compensation water tank (9) and the fuel cell stack (1) cooling liquid inlet end, and the compensation water tank (9) is further connected with the fuel cell stack (1) cooling liquid outlet end and the water pump (8).

[0085] The AC impedance device (2) is used to monitor whether the stack impedance value reaches the low-temperature shutdown required value.

[0086] The ejector (20) can be replaced by a hydrogen circulation pump, and the anode water distribution device (23) is connected with the ejector (20).

[0087] The electrically controlled three-way valve (16) can be replaced by an air inlet valve.

[0088] By the device of the embodiment, the self-heating technology can be realized when the fuel cell system has no external heater.

[0089] Embodiment 4

[0090] According to the embodiments provided in Embodiment 1, the embodiment provides a purge control system of a fuel cell, comprising:

[0091] A fuel cell control module is used to detect whether cold purge is needed when receiving a fuel cell system shutdown instruction;

[0092] A purge execution module is used to execute the fuel cell system normal-temperature purge or cold purge operation;

[0093] A shutdown module is used to execute normal-temperature purge and then shutdown or shutdown after judging that the stack online impedance value in the cold purge process is higher than a preset calibrated impedance value.

[0094] Embodiment 5

[0095] According to the embodiments provided in Embodiment 1, the embodiment provides a purge control device of a fuel cell, comprising:

[0096] A memory is used to store a computer program;

[0097] a processor for implementing the steps of the fuel cell purging control method according to any one of the embodiments 1 when the computer program is executed.

[0098] Embodiment 6

[0099] According to the embodiments provided in Embodiment 1, this embodiment also provides a computer storage medium, and the computer storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the fuel cell purging control method according to any one of the embodiments 1.

[0100] As can be seen from the above embodiments, the self-heating technology is realized without an external heater, and when the fuel cell system is shut down due to insufficient stack temperature caused by a front working condition, the FCU can control the stack to self-heat and control the flow of the cooling liquid of the heating circulation system, so as to realize the normal purging of the fuel cell system, and the AC impedance element is monitored to determine whether the purging is completed, and in the implementation process of the device, the service life of the stack is not damaged, the structure of the existing fuel cell system is simplified, and the cost is saved.

[0101] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is based on the content of the specification and drawings of the present application, is also included in the patent protection scope of the present application.

Claims

1. A purge control method of a fuel cell, characterized by: The method comprises the following steps: When the FCU receives a fuel cell system shutdown instruction, it is detected whether cold purge is needed; If the fuel cell system needs cold purge, the stack temperature is confirmed and cold purge is performed based on a preset cold purge strategy; If the fuel cell system does not need cold purge, normal temperature purge is performed; The stack temperature confirmation comprises: It is determined whether the water temperature at the stack outlet is higher than a preset calibration temperature; If yes, the preset cold purge strategy is executed, If no, a self-heating state is entered until the water temperature at the stack outlet is higher than the preset calibration temperature, and then the preset cold purge strategy is executed; The self-heating state comprises reducing the cathode metering ratio and controlling the coolant flow rate; The preset cold purge strategy comprises increasing the air flow rate in the fuel cell system and monitoring the stack online impedance value; In the process of performing cold purge based on the preset cold purge strategy after the stack temperature is confirmed, the method further comprises: It is determined whether the stack online impedance value is higher than a preset calibration impedance value; If yes, the cold purge is stopped, and the fuel cell system shutdown instruction is accepted, If no, the cold purge is continued.

2. The purge control method of a fuel cell according to claim 1, characterized by: The cathode metering ratio is determined by calibration of the stack current and stack voltage at different air metering ratios.

3. The purge control method of a fuel cell according to claim 1, characterized by: The detection of whether cold purge is needed comprises: The temperature sensor monitoring information or cloud platform monitoring weather data is used to confirm whether cold purge is needed.

4. A purge control system of a fuel cell, which implements the purge control method of any one of claims 1 to 3, characterized by: It comprises: A fuel cell control module for detecting whether cold purge is needed when receiving a fuel cell system shutdown instruction; A purge execution module for performing normal temperature purge or cold purge operation of the fuel cell system; A shutdown module for performing shutdown after normal temperature purge or shutdown after determining that the stack online impedance value is higher than a preset calibration impedance value during cold purge.

5. A purge control apparatus of a fuel cell, characterized by comprising: It comprises: A memory for storing a computer program; A processor for executing the computer program to implement the steps of the fuel cell purge control method according to any one of claims 1-3.

6. A computer storage medium having stored thereon a computer program, characterized in that: The computer program is executed by the processor to implement the steps of the fuel cell purge control method according to any one of claims 1-3.

Images