Drainage control method, device and system of fuel cell, vehicle and medium

Abstract

The invention discloses a drainage control method, device and system of a fuel cell, a vehicle and a medium, and relates to the technical field of fuel cells, and the method can obtain the gaseous water flow at an anode inlet of the fuel cell, the water flow entering an anode from a cathode and the saturated water vapor flow at an anode outlet of the fuel cell in real time. The total water flow generated by the fuel cell in the current power generation state and the saturated steam flow of the anode outlet of the fuel cell are combined to calculate the water flow of liquid water at the anode outlet of the fuel cell, and the opening time of the drain valve is adjusted by referring to the water flow of the liquid water. Therefore, the adjusted starting time can be matched with the current power generation state of the fuel cell, liquid water generated in the power generation state is discharged to the outside, and the accuracy of drainage control is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a drainage control method, device, system, vehicle and medium for a fuel cell. Background Art

[0002] For a fuel cell to operate efficiently and reliably, it needs a certain amount of water inside. On the one hand, the proton exchange membrane needs to be kept moist, which not only improves the transmission efficiency of hydrogen ions, but also increases the life of the fuel cell. On the other hand, there cannot be too much water inside the fuel cell, as too much water will block the gas transmission channel, causing "flooding" and reducing the performance of the fuel cell. Affected by factors such as the temperature and pressure inside the fuel cell, water will exist inside the fuel cell in three states: gaseous water, liquid water, and membrane water. Liquid water is an undesirable state, so it is necessary to drain the liquid water to the external environment through the drain valve.

[0003] At present, the general method is to monitor the fuel cell power generation current, determine the amount of water generated corresponding to the power generation current by looking up the table, and preliminarily give a drainage strategy. Then, through bench calibration, it is observed whether the fuel cell voltage drops, and the drainage time adjustment amount corresponding to the voltage drop value is determined by looking up the table. The drainage time is adjusted. This method is difficult to accurately respond to changes in the actual power generation state of the fuel cell, and the accuracy of drainage control is poor. Summary of the invention

[0004] Embodiments of the present invention provide a drainage control method, device, system, vehicle and medium for a fuel cell to solve the problem of poor drainage control accuracy.

[0005] In a first aspect, a drainage control method for a fuel cell is provided, the method comprising: obtaining in real time the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell; obtaining the water flow of liquid water at the anode outlet of the fuel cell according to the gaseous water flow, the water flow entering the anode from the cathode, and the saturated water vapor flow; and adjusting the opening time of the fuel cell drainage valve according to the liquid water flow, so as to open the drainage valve to drain water at the adjusted opening time.

[0006] In a second aspect, a drainage control device for a fuel cell is provided, the device comprising: an acquisition module for acquiring in real time the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell; a calculation module for obtaining the water flow of liquid water at the anode outlet of the fuel cell based on the gaseous water flow, the water flow entering the anode from the cathode, and the saturated water vapor flow; a control module for adjusting the opening time of the fuel cell drainage valve according to the water flow of the liquid water, so as to open the drainage valve to drain water at the adjusted opening time.

[0007] In a third aspect, a fuel cell system is provided, comprising an operation support system and a control system of the fuel cell, wherein the operation support system of the fuel cell is connected to the control system, and the control system is used to execute the steps of the drainage control method of the fuel cell described in the first aspect.

[0008] In a fourth aspect, a vehicle is provided, comprising the fuel cell system described in the third aspect.

[0009] In a fifth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned fuel cell drainage control method are implemented.

[0010] In one scheme implemented by the drainage control method, device, system, vehicle and medium of the above-mentioned fuel cell, the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell can be obtained in real time. The total water flow generated by the fuel cell under the current power generation state and the saturated water vapor flow at the anode outlet of the fuel cell are combined to calculate the water flow that will become liquid water at the anode outlet of the fuel cell. The opening time of the drain valve is adjusted with reference to the water flow of the liquid water so that the adjusted opening time can match the current power generation state of the fuel cell, and the liquid water generated under the power generation state is discharged to the outside, thereby improving the accuracy of drainage control. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0012] Figure 1 is a schematic diagram of an operation support system of a fuel cell in one embodiment of the present invention; Figure 2is a flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Figure 3 is another flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Figure 4 is another flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Figure 5 is another flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Figure 6 is another flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Figure 7 is another flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Figure 8 is another flow chart of a drainage control method for a fuel cell in one embodiment of the present invention; Fig. 9 is a schematic diagram of a drainage control device for a fuel cell in one embodiment of the present invention; Fig.10 is a schematic diagram of a fuel cell system in one embodiment of the present invention; Fig.11 is a schematic block diagram of a vehicle in one embodiment of the present invention. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] The operation support system of the fuel cell can be understood as a system composed of other pipelines / components in the fuel cell system except the control system, which supports the operation of the fuel cell. For example, it can include the fuel cell body, air supply system, hydrogen supply system, thermal management system, water management system, etc.

[0015] like Figure 1As shown, the operation support system of the fuel cell may include the following components: an air filter 1, an air compressor 2, an intercooler 3, a humidifier 4, an inlet shut-off valve 5, an outlet shut-off valve 6, an air inlet pressure sensor 7, a high-pressure gas cylinder 8, a pressure reducing valve 9, a hydrogen injection valve 10, an anode inlet pressure sensor 11, a gas-water separator 12, an exhaust valve 13, a hydrogen circulation device 14, a coolant outlet temperature sensor 15, a water pump 16, a three-way valve 17, a heater (PTC) 18, a radiator 19, a drain valve 20, a coolant inlet temperature sensor 21, an anode outlet pressure sensor 22, and a fuel cell 23.

[0016] The components in the operation support system of the fuel cell can be connected to the control system so that the control system can control each component. For example, the anode inlet pressure sensor 11, the coolant outlet temperature sensor 15, the drain valve 20, the coolant inlet temperature sensor 21, and the anode outlet pressure sensor 22 are respectively connected to the control system so that the control system can obtain the pressure signal collected by the pressure sensor, the temperature signal collected by the temperature sensor, and control the opening and closing of the exhaust valve.

[0017] The drainage control method of the fuel cell provided by the present invention can be applied to the control system in the fuel cell system. The control system calculates the water flow rate of liquid water to be discharged by the drain valve 20 by executing the drainage control method of the fuel cell provided by the present application, by obtaining the water flow rate of various forms of water inside the anode of the fuel cell 23 in the operation support system in real time (such as the gaseous water flow rate at the anode inlet of the fuel cell, the water flow rate entering the anode from the cathode), and the maximum water vapor flow rate that the anode can accommodate (such as the saturated water vapor flow rate at the anode outlet of the fuel cell). Then, based on the water flow rate to be discharged by the drain valve 20, the drainage control strategy of the drain valve 20 is adjusted so that the adjusted drainage control strategy can match the current power generation state of the fuel cell, thereby improving the accuracy of drainage control.

[0018] For example, the opening time of the drain valve 20 is adjusted to discharge the liquid water at the anode of the fuel cell 23 in time to prevent the accumulated liquid water from blocking the gas transmission channel and causing "flooding" of the fuel cell, thereby reducing the performance of the fuel cell.

[0019] like Figure 2 As shown, a fuel cell drainage control method proposed in an embodiment of the present application may include the following steps: S201, real-time acquisition of the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell.

[0020] During the operation of the fuel cell system and the power generation of the fuel cell, the control system obtains in real time the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell.

[0021] Fuel cells generate water at the cathode and typically remove it at the anode.

[0022] In a fuel cell, water moves between the cathode and the anode under the influence of various phenomena such as electroosmotic drag and concentration permeation. In this embodiment, the water flow from the cathode to the anode can be understood as the water flow from the cathode to the anode after integrating various phenomena inside the fuel cell.

[0023] Preferably, the water flow / flow rate of various forms of water in the present application can be measured in mol / s, and mol / s is used to quantify the amount of material passing through a certain cross section per unit time. In this way, the calculated water flow rate will not be changed by the change of water form, which facilitates the comprehensive calculation of various water flow rates.

[0024] The above-mentioned gaseous water flow rate, the water flow rate entering the anode from the cathode and the saturated water vapor flow rate at the anode outlet of the fuel cell can be obtained by measurement / calculation.

[0025] In some embodiments, when calculating the saturated water vapor flow rate at the anode outlet of the fuel cell, the relative humidity at the anode outlet can be 100% as a prerequisite, that is, the saturated water vapor flow rate in this embodiment is the saturated water vapor flow rate when the relative humidity at the anode outlet is 100%.

[0026] On the one hand, a large number of tests have confirmed that the water content at the anode outlet of the fuel cell can indeed reach a saturated state; on the other hand, when the water content at the anode outlet reaches a saturated state, the water vapor that the fuel cell can accommodate at this temperature and pressure has reached saturation, and the water vapor that cannot be accommodated is very likely to become liquid water, and the flow of this part of water can be used as the water flow that needs to be discharged by the drain valve.

[0027] S202, obtaining the flow rate of liquid water at the anode outlet of the fuel cell according to the flow rate of gaseous water, the flow rate of water entering the anode from the cathode, and the flow rate of saturated water vapor.

[0028] As a feasible implementation, the sum of the gaseous water flow and the water flow entering the anode from the cathode is subtracted from the saturated water vapor flow, and the final difference can be considered as the flow of gaseous water (i.e., water vapor) that can no longer be accommodated at the anode outlet of the fuel cell under the condition of 100% relative humidity, that is, the flow that will become liquid water. In this example, the flow of gaseous water that the fuel cell can no longer accommodate can be used as the above-mentioned "water flow of liquid water at the anode outlet of the fuel cell".

[0029] As another feasible implementation, the saturated water vapor flow rate can be subtracted from the sum of the gaseous water flow rate and the water flow rate entering the anode from the cathode to obtain the flow rate of gaseous water that the fuel cell can no longer accommodate. Then, the flow rate of gaseous water, the temperature and pressure at the anode outlet can be combined to determine the water flow rate that can be liquefied from gas to liquid, which is used as the water flow rate of liquid water at the anode outlet of the above-mentioned fuel cell.

[0030] This embodiment takes into account the critical state of the water phase change inside the fuel cell, that is, liquid water will appear only when the water inside the fuel cell reaches the saturated vapor pressure state. If the calculated total water flow newly accumulated at the anode (that is, the sum of the gaseous water flow at the anode inlet of the fuel cell and the water flow entering the anode from the cathode) is directly used as the water flow that needs to be discharged by the drain valve, it may cause multiple drains. Therefore, this application takes into account the saturated water vapor flow at the anode outlet of the fuel cell when calculating the water flow that needs to be discharged by the drain valve.

[0031] Because if all the water accumulated at the anode inlet within the two drainage intervals is drained, the water inside the fuel cell may not reach the saturated vapor pressure state, and no liquid water will appear at this time. Therefore, if the total water flow accumulated at the anode inlet is used as the water flow to be discharged by the drain valve, then when the drain valve is opened based on the water flow to be discharged by the drain valve, there may actually be no liquid water discharged or the amount of liquid water discharged is small, and the open drain valve is likely to cause gaseous water or even hydrogen leakage, resulting in hydrogen waste.

[0032] S203, adjusting the opening time of the fuel cell drain valve according to the water flow rate of the liquid water, so that the drain valve is opened to drain water at the adjusted opening time.

[0033] As a feasible implementation, the water flow rate of the liquid water calculated in the above step S202 can be directly used as the water flow rate to be discharged by the drain valve.

[0034] As another feasible implementation, the liquid water flow rate calculated in step S202 is Gas-water separator efficiency The product of ,Right now .

[0035] The gas-water separator efficiency η can be set according to test experience and is not limited in this application. For example, it can be set within the range of 80% to 98%.

[0036] like Figure 1As shown, a gas-water separator 12 is provided at the anode outlet of the fuel cell. The gas-water separator 12 can store a certain amount of liquid water. In this embodiment, when the water flow rate of the above-mentioned liquid water is large, the opening time of the drain valve can be advanced to discharge the liquid water stored in the gas-water separator in time, so as to prevent excessive liquid water from accumulating in the fuel cell and affecting the performance of the fuel cell.

[0037] In summary, the drainage control method of the fuel cell proposed in the embodiment of the present application obtains in real time the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell, and calculates the water flow that will become liquid water at the anode outlet of the fuel cell by combining the total water flow generated by the fuel cell under the current power generation state and the saturated water vapor flow at the anode outlet of the fuel cell. The opening time of the drain valve is adjusted with reference to the water flow of the liquid water so that the adjusted opening time can match the current power generation state of the fuel cell, and the liquid water generated under the power generation state is discharged to the outside, thereby improving the accuracy of drainage control.

[0038] Based on the above embodiments, Figure 3 As shown, the above step S203 of "adjusting the opening time of the fuel cell drain valve according to the water flow rate of the liquid water" may include the following steps: S301, determining whether the flow rate of liquid water is greater than a preset threshold.

[0039] S302, if it is greater than, determining the maximum water storage time of the gas-water separator according to the water flow rate of the liquid water and the maximum water storage capacity of the gas-water separator of the fuel cell; S303, adjusting the opening time of the drain valve according to the maximum water storage time.

[0040] The above preset thresholds can be set as needed and are not limited in this application.

[0041] For example, the preset threshold is set to 0, and when the flow rate of liquid water is greater than 0, the maximum water storage time of the gas-water separator is determined based on the flow rate of liquid water and the maximum water storage capacity of the gas-water separator of the fuel cell.

[0042] If the maximum water storage capacity of the gas-water separator is , then the time interval between the adjusted opening time and the current time can be calculated according to the following formula : in, is the maximum water storage capacity of the gas-water separator, in L; The time interval between the adjusted start time and the current time, in seconds; is the density of liquid water in g / L, is the water flow rate of the above liquid water, in mol / s.

[0043] Based on the current moment, superimpose the time interval , and get the adjusted opening time.

[0044] When the flow rate of liquid water is less than or equal to 0, no opening time adjustment is performed.

[0045] In some embodiments, after the drain valve is opened, a preset opening time length, such as 0.5S, can be set. After the drain valve is opened for 0.5S, the drain valve is closed.

[0046] In some embodiments, the opening time can be calculated based on the maximum water storage capacity of the gas-water separator and the drainage flow rate of the drainage valve.

[0047] This embodiment starts calculating and adjusting the opening time of the drain valve when the water flow rate of liquid water that may be generated by the fuel cell is greater than a preset threshold, and determines the adjusted opening time in combination with the maximum water storage capacity of the gas-water separator, so that the drain valve can be opened in time to drain water before the volume of liquid water generated exceeds the maximum water storage capacity of the gas-water separator.

[0048] Based on the above embodiments, Figure 4 As shown, after the above step S203, the drainage control method of the fuel cell proposed in the embodiment of the present application further includes the following steps: S401, obtaining the inlet pressure value of the drain valve; S402, obtaining the drainage flow of the drainage valve corresponding to the inlet pressure value; S403, determining a single opening time of the drain valve according to the water flow of the liquid water, the adjusted opening time and the drainage flow of the drain valve, so as to open the drain valve according to the single opening time.

[0049] like Figure 1 As shown, an anode outlet pressure sensor 22 is provided at the anode outlet of the fuel cell.

[0050] In this embodiment, the anode outlet pressure sensor 22 can be used to measure the pressure value of the anode outlet of the fuel cell, and the pressure value can be used as the pressure value of the drain valve inlet.

[0051] The drainage volume of the drain valve is affected by the inlet pressure of the drain valve. This embodiment can determine the drainage flow rate of the drain valve corresponding to the current inlet pressure of the drain valve.

[0052] For example, the correspondence between the drain flow of the drain valve and the inlet pressure value of the drain valve can be pre-calibrated, and a Map table of the correspondence can be generated. When the drain flow of the drain valve needs to be obtained, the Map table can be searched using the inlet pressure value of the drain valve obtained in real time.

[0053] The single opening duration can be calculated by the following formula: in, is the maximum water storage capacity of the gas-water separator, in L, is the single opening time of the drain valve, in seconds; Q is the drainage flow rate of the drain valve, in g / s.

[0054] After determining the opening time of the drain valve in the above embodiment, this embodiment further determines the current drainage flow rate of the drain valve according to the pressure value at the drain valve inlet, and then determines the time required to discharge the water stored in the gas-water separator at the drainage flow rate, so as to determine the single opening time of the drain valve, so as to avoid opening the drain valve for a long time and causing leakage of hydrogen.

[0055] Based on the above embodiments, Figure 5 As shown, the above step S201 of "real-time acquisition of gaseous water flow at the anode inlet of the fuel cell" may include the following steps: S501, acquiring in real time a first temperature value of a fuel cell anode inlet, a first pressure value of a fuel cell anode inlet, and a current value of the fuel cell.

[0056] Regarding the first temperature value: the temperature of the anode inlet is equal to the temperature of the fuel cell coolant outlet, which can be obtained by Figure 1 The coolant outlet temperature sensor 15 obtains a first temperature value.

[0057] Regarding the first pressure value: Figure 1 The anode inlet pressure is measured by sensor 11.

[0058] S502, obtaining the humidity of the anode inlet of the fuel cell.

[0059] The anode inlet humidity can be calculated according to the target humidity value required by the fuel cell, that is, given as a known quantity. In this way, on the one hand, there is no need to install a humidity sensor at the anode inlet, reducing system cost and complexity; on the other hand, the gas humidity required by the fuel cell is also the control target of the system. Therefore, when making the drainage strategy, it is assumed that the anode inlet humidity has met the requirements of the fuel cell, so as to calculate the gaseous water flow brought into the anode in this case.

[0060] S503, calculating the total target gas flow at the anode inlet of the fuel cell according to the current value, where the total target gas flow is the sum of the flow rates of other gases except the flow rate of gaseous water.

[0061] The total gas flow rate may include but is not limited to gaseous water flow rate, dry hydrogen flow rate, reflux hydrogen flow rate and reflux nitrogen flow rate. The total target gas flow rate may include but is not limited to dry hydrogen flow rate, reflux hydrogen flow rate and reflux nitrogen flow rate.

[0062] The dry hydrogen flow rate, the recirculating hydrogen flow rate, and the recirculating nitrogen flow rate vary under the influence of the current value output from the fuel cell.

[0063] In the embodiment of the present application, when the current value at the current moment is acquired in real time, the dry hydrogen flow rate, the reflux hydrogen flow rate and the reflux nitrogen flow rate at the current value are calculated.

[0064] S504, calculating the anode inlet saturated vapor pressure corresponding to the first temperature value; S505, dividing the product of the saturated vapor pressure and humidity at the anode inlet by the first pressure value to obtain a volume percentage of gaseous water at the anode inlet; S506, calculating the gaseous water flow rate according to the volume ratio of the gaseous water at the anode inlet and the total flow rate of the target gas.

[0065] The saturated vapor pressure at the anode inlet is represented by P1 (in kPa). The saturated vapor pressure at the first temperature value T1 (in K) can be calculated and obtained as the saturated vapor pressure at the anode inlet.

[0066] The volume proportion of gaseous water at the anode inlet is: in, is the humidity at the anode inlet, in %; is the first pressure value, in kPa.

[0067] The gaseous water flow rate at the anode inlet of the fuel cell is: in, is the gaseous water flow rate at the anode inlet of the fuel cell, is the dry hydrogen flow rate at the anode inlet of the fuel cell, is the reflux hydrogen flow rate at the anode inlet of the fuel cell, is the reflux nitrogen flow rate at the anode inlet of the fuel cell; the units of the above-mentioned gaseous water flow rate, dry hydrogen flow rate, reflux hydrogen flow rate and reflux nitrogen flow rate are all mol / s.

[0068] This embodiment provides a method for calculating the gaseous water flow rate at the anode inlet of a fuel cell according to the real-time anode inlet temperature, anode inlet pressure, and current value of the fuel cell. This method does not require additional sensor equipment in the fuel cell system, and the existing hardware equipment in the fuel cell system can be used to obtain the required anode inlet temperature, anode inlet pressure, and current value. This allows the drainage strategy to be adjusted in real time according to the temperature and pressure changes of the fuel cell, which is more accurate than the fixed drainage strategy and the rough adjustment based on the table lookup, and avoids the waste of hydrogen caused by excessive discharge of hydrogen, the reduction of system efficiency, and safety issues.

[0069] Based on the above embodiments, Figure 6 As shown, the above step S503 of "calculating the target total gas flow at the anode inlet of the fuel cell according to the current value" may include the following steps: S601, calculating the dry hydrogen flow rate and the reflux hydrogen flow rate at the anode inlet of the fuel cell according to the current value.

[0070] S602, calculating the reflux nitrogen flow rate at the anode inlet of the fuel cell according to the reflux hydrogen flow rate and a preset ratio value, wherein the preset ratio value is the ratio of the hydrogen flow rate to the total flow rate of hydrogen and nitrogen gas in the reflux gas at the anode inlet of the fuel cell; S603, taking the sum of the dry hydrogen flow rate, the reflux hydrogen flow rate and the reflux nitrogen flow rate as the total target gas flow rate.

[0071] The total target gas flow at the anode inlet of the fuel cell is the sum of the dry hydrogen flow, the reflux hydrogen flow and the reflux nitrogen flow.

[0072] The dry hydrogen flow rate can be calculated from the current value and the hydrogen utilization rate. The specific calculation method is as follows: in, is the dry hydrogen flow rate at the anode inlet of the fuel cell, in mol / s; I is the current value of the fuel cell, in A; n is the number of single cells in the fuel cell; F is the Faraday constant 96485C / mol; It is the hydrogen utilization rate (such as the hydrogen utilization rate of a fuel cell engine), which can generally be 90%~99%.

[0073] The reflux hydrogen flow rate is calculated from the current value and the stoichiometric ratio. The specific calculation method is as follows: in, is the reflux hydrogen flow rate at the anode inlet of the fuel cell, in mol / s; is the stoichiometric ratio of hydrogen; I is the current value of the fuel cell, in A; n is the number of fuel cell cells; F is the Faraday constant 96485C / mol.

[0074] The reflux nitrogen flow rate is calculated from the reflux hydrogen flow rate and the ratio of hydrogen to the total flow rate of hydrogen and nitrogen in the reflux gas at the anode inlet of the fuel cell. The specific calculation method is as follows: in, is the reflux nitrogen flow rate at the anode inlet of the fuel cell, in mol / s; is the reflux hydrogen flow rate at the anode inlet of the fuel cell, in mol / s; It is the ratio of hydrogen to the total flow of hydrogen and nitrogen in the return gas at the anode inlet of the fuel cell. It can be 80%~90%, and the specific value is not limited in this application.

[0075] This embodiment provides a method for calculating the dry hydrogen flow rate, reflux hydrogen flow rate and reflux nitrogen flow rate at the anode inlet of the fuel cell based on the real-time current value of the fuel cell. This method can obtain the constantly changing dry hydrogen flow rate, reflux hydrogen flow rate and reflux nitrogen flow rate in real time without adding additional equipment, thereby providing a data basis for determining the water flow rate of liquid water generated by the fuel cell.

[0076] Based on the above embodiments, Figure 7 As shown, in the above step S201, "real-time acquisition of water flow from the cathode to the anode" includes the following steps: S701, acquiring in real time a second temperature value at an outlet of an anode of a fuel cell and a second pressure value at an outlet of an anode of a fuel cell.

[0077] Available through Figure 1 The coolant inlet temperature sensor 21 obtains the second temperature value through Figure 1 The anode outlet pressure sensor 22 acquires a second pressure value.

[0078] S702, obtaining the water content in the membrane corresponding to the second temperature value, the second pressure value and the humidity at the anode inlet of the fuel cell, and the concentration gradient of the water content in the membrane, wherein the water content in the membrane is the water content in the membrane of the proton exchange membrane in the fuel cell; S703, obtaining a diffusion rate corresponding to the water content in the membrane and the second temperature value, the diffusion rate being the diffusion rate of water in the proton exchange membrane; S704, determining the water flow rate diffusing from the cathode into the anode according to the diffusion rate and the concentration gradient as the first water flow rate; S705, obtaining an electroosmotic drag coefficient corresponding to the water content in the membrane, where the electroosmotic drag coefficient is the electroosmotic drag coefficient of the proton exchange membrane; S706, determining the water flow rate electroosmotically dragged from the anode to the cathode as the second water flow rate according to the electroosmotic drag coefficient; S707, subtract the second water flow rate from the first water flow rate to obtain the water flow rate entering the anode from the cathode.

[0079] The water flow rate that permeates from the cathode into the anode due to concentration diffusion can be calculated based on the diffusion rate of water in the proton exchange membrane, the dry membrane density, the equivalent value of the membrane, the water content in the membrane, and the effective electrode area of ​​the membrane.

[0080] For a known membrane, the water content in the membrane is related to temperature, humidity and pressure, and a map of the water content in the membrane under these three variables can be tested in advance.

[0081] For example, a correspondence is established between the second temperature value, the second pressure value, the humidity at the anode inlet of the fuel cell and the water content in the proton exchange membrane, and a map of the correspondence is generated. When the water content in the membrane needs to be obtained, the second temperature value, the second pressure value and the humidity at the anode inlet obtained in real time are obtained by looking up the table.

[0082] Due to concentration diffusion, the water transmembrane flux from the cathode to the anode is: in, The unit is mol / / s; is the dry film density, unit is kg / ; is the equivalent value of the membrane, in kg / mol; is the diffusion rate of water in the proton exchange membrane, in / s; is the concentration gradient of water content in the membrane.

[0083] The concentration gradient can be obtained by looking up a table.

[0084] The diffusion rate of water in the proton exchange membrane is The calculation formula is as follows: in, is the water content in the membrane, is the second temperature value, in K.

[0085] The water flow rate (i.e., the first water flow rate) that permeates from the cathode to the anode by concentration diffusion is calculated based on the water transmembrane flux: in, is the first water flow rate, in mol / s, A is the membrane electrode effective area, in .

[0086] The water flow rate from the anode to the cathode due to electroosmotic drag can be calculated based on the electroosmotic drag coefficient and current density, where the electroosmotic drag coefficient is related to the water content in the membrane.

[0087] The water flow rate transported from the anode to the cathode due to electroosmotic drag (i.e., the second water flow rate) can be calculated as follows: The transmembrane flux of water transported from the anode to the cathode due to electroosmotic drag is: in, is the water transmembrane flux from the anode to the cathode due to electroosmotic drag, in mol / / s; is the electroosmotic drag coefficient, , is the water content in the membrane; is the fuel cell current density, in A / .

[0088] Based on water transmembrane flux Calculate the water flow rate transported from the anode to the cathode due to electroosmotic drag (i.e., the second water flow rate): in, is the second water flow rate, in mol / s; A is the effective area of ​​the membrane electrode, in .

[0089] The present embodiment provides a method for calculating the water flow rate entering the anode from the cathode in the fuel cell based on the real-time anode outlet temperature, anode outlet pressure, and anode inlet humidity of the fuel cell. This method does not require the installation of other measuring equipment in the fuel cell system. The existing hardware equipment in the fuel cell system can be used to obtain the water flow rate that penetrates from the cathode into the anode due to concentration diffusion in the current discharge state of the fuel cell, and the water flow rate that is transported from the anode to the cathode due to electroosmotic drag. The movement of water under these two phenomena is combined to comprehensively calculate the water flow rate entering the anode from the cathode inside the fuel cell.

[0090] Based on the above embodiments, Figure 8 As shown, the above step S201 of "real-time acquisition of the saturated water vapor flow rate at the anode outlet of the fuel cell" may include the following steps: S801, calculating the anode outlet saturated vapor pressure corresponding to the second temperature value of the anode outlet of the fuel cell.

[0091] S802, taking the ratio of the anode outlet saturated vapor pressure to the second pressure value at the anode outlet of the fuel cell as the proportion of saturated water vapor in the anode outlet gas, where the anode outlet gas includes saturated water vapor, anode outlet hydrogen and anode outlet nitrogen.

[0092] S803, obtaining the saturated water vapor flow rate at the anode outlet of the fuel cell according to the sum of the flow rate of the hydrogen gas at the anode outlet and the flow rate of the nitrogen gas at the anode outlet and their proportion.

[0093] The flow rate of hydrogen at the anode outlet is the sum of the flow rate of reflux hydrogen at the anode outlet of the fuel cell and the flow rate of hydrogen discharged through the exhaust valve.

[0094] The flow rate of nitrogen at the anode outlet is the sum of the flow rate of reflux nitrogen at the anode outlet of the fuel cell and the flow rate of nitrogen discharged through the exhaust valve.

[0095] In the embodiment of the present application, the saturated vapor pressure at the anode outlet at the temperature value can be calculated based on the second temperature value at the anode outlet of the fuel cell.

[0096] When the relative humidity at the anode outlet is 100%, the water vapor partial pressure at the anode outlet under saturation is is equal to the saturated vapor pressure at the anode outlet, so the proportion of saturated water vapor in the anode outlet gas can be obtained: in, is the proportion of saturated water vapor in the anode outlet gas; is the saturated vapor pressure at the anode outlet of the fuel cell, in kPa; is the second pressure value, in kPa.

[0097] The flow rate of hydrogen at the anode outlet is the sum of the flow rate of reflux hydrogen and the flow rate of hydrogen at the anode outlet. Figure 1 The sum of the hydrogen flow rates discharged from the exhaust valve 13. is the hydrogen utilization rate of the fuel cell, then the ratio of the discharged hydrogen flow to the dry hydrogen flow is .

[0098] In this way, the flow rate of hydrogen at the anode outlet can be calculated by the following formula: in, is the flow rate of hydrogen at the anode outlet, in mol / s, is the reflux hydrogen flow rate at the anode inlet, in mol / s, , unit is mol / s.

[0099] The flow rate of nitrogen at the anode outlet is the sum of the reflux nitrogen flow rate and the nitrogen flow rate discharged through the exhaust valve 13. Here, the proportion of the discharged nitrogen flow rate to the total flow rate of nitrogen at the anode outlet can be obtained in advance through testing, which is recorded as The flow rate of nitrogen at the anode outlet can be calculated by the following formula: in, The unit is mol / s.

[0100] In this way, the saturated water vapor flow rate at the anode outlet can be calculated by the following formula: in, The unit is mol / s.

[0101] In the embodiment of the present application, the saturated vapor pressure at the anode outlet can be determined according to the second temperature value at the anode outlet. When the relative humidity at the anode outlet is 100%, the water vapor partial pressure at the anode outlet in the saturated state is equal to the saturated vapor pressure at the anode outlet. In this way, the water vapor partial pressure at the anode outlet in the saturated state can be obtained by calculation. The proportion of saturated water vapor at the anode outlet in the anode outlet gas can be obtained by combining the water vapor partial pressure and the second pressure at the anode outlet. The saturated water vapor flow rate at the anode outlet can be obtained by combining the proportion and the flow rate of gases other than water vapor in the anode outlet gas (i.e., the anode outlet hydrogen flow rate and the anode outlet nitrogen flow rate). In this way, the saturated vapor flow rate at the anode outlet can be accurately calculated without adding additional equipment.

[0102] The drainage control method of the fuel cell proposed in this application accurately calculates the water flow rate of the liquid water generated in the fuel cell through the current, pressure, and temperature signals that can be collected by the current fuel cell system, and adjusts the drainage strategy based on the water flow rate to achieve accurate drainage and improve the efficiency and reliability of the fuel cell. The present invention does not need to add additional sensors or monitoring equipment to the hardware basic conditions of the original fuel cell system, and does not increase the system cost. This method is applied to the fuel cell engine, and it is expected that the hydrogen utilization rate can be increased to 97% when the fuel cell engine is running stably at low power. At the same time, it can also effectively prevent the fuel cell from being flooded due to insufficient drainage.

[0103] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0104] In one embodiment, a drainage control device for a fuel cell is provided, and the drainage control device for the fuel cell corresponds one-to-one to the drainage control method for the fuel cell in the above embodiment. Fig. 9As shown, the drainage control device 900 of the fuel cell includes an acquisition module 901 , a calculation module 902 and a control module 903 .

[0105] An acquisition module 901 is used to acquire in real time the gaseous water flow rate at the anode inlet of the fuel cell, the water flow rate entering the anode from the cathode, and the saturated water vapor flow rate at the anode outlet of the fuel cell; A calculation module 902 is used to obtain the flow rate of liquid water at the anode outlet of the fuel cell according to the gaseous water flow rate, the water flow rate entering the anode from the cathode and the saturated water vapor flow rate; The control module 903 is used to adjust the opening time of the fuel cell drain valve according to the water flow rate of the liquid water, so as to open the drain valve to drain water at the adjusted opening time.

[0106] In some embodiments, the control module is used to determine whether the water flow rate of the liquid water is greater than a preset threshold; if greater, the maximum water storage time of the gas-water separator is determined based on the water flow rate of the liquid water and the maximum water storage capacity of the gas-water separator of the fuel cell; and the opening time of the drain valve is adjusted according to the maximum water storage time.

[0107] In some embodiments, the control module is also used to: obtain the inlet pressure value of the drain valve; obtain the drain flow of the drain valve corresponding to the inlet pressure value; determine the single opening time of the drain valve according to the water flow of liquid water, the adjusted opening time and the drain flow of the drain valve, so as to open the drain valve according to the single opening time.

[0108] In some embodiments, an acquisition module is used to acquire in real time a first temperature value at the anode inlet of a fuel cell, a first pressure value at the anode inlet of the fuel cell, and a current value of the fuel cell; acquire the humidity at the anode inlet of the fuel cell; calculate a target total gas flow rate at the anode inlet of the fuel cell based on the current value, wherein the target total gas flow rate is the sum of the flow rates of other gases except the gaseous water flow rate; calculate the saturated vapor pressure at the anode inlet corresponding to the first temperature value; divide the product of the saturated vapor pressure at the anode inlet and the humidity by the first pressure value to obtain the volume ratio of gaseous water at the anode inlet; and calculate the gaseous water flow rate based on the volume ratio of gaseous water at the anode inlet and the target total gas flow rate.

[0109] In some embodiments, the acquisition module is used to: calculate the dry hydrogen flow and the reflux hydrogen flow at the anode inlet of the fuel cell according to the current value; calculate the reflux nitrogen flow at the anode inlet of the fuel cell according to the reflux hydrogen flow and a preset ratio value, the preset ratio value being the ratio of the hydrogen flow to the total hydrogen and nitrogen gas flow in the reflux gas at the anode inlet of the fuel cell; and take the sum of the dry hydrogen flow, the reflux hydrogen flow and the reflux nitrogen flow as the total flow of the target gas.

[0110] In some embodiments, an acquisition module is used to acquire in real time a second temperature value at an anode outlet of a fuel cell and a second pressure value at an anode outlet of the fuel cell; acquire the water content in the membrane corresponding to the second temperature value, the second pressure value and the humidity at an anode inlet of the fuel cell, and the concentration gradient of the water content in the membrane, wherein the water content in the membrane is the water content in the proton exchange membrane in the fuel cell; acquire the diffusion rate corresponding to the water content in the membrane and the second temperature value, wherein the diffusion rate is the diffusion rate of water in the proton exchange membrane; determine the water flow rate diffused from the cathode into the anode as the first water flow rate based on the diffusion rate and the concentration gradient; acquire the electroosmotic drag coefficient corresponding to the water content in the membrane, wherein the electroosmotic drag coefficient is the electroosmotic drag coefficient of the proton exchange membrane; determine the water flow rate electroosmotically dragged from the anode to the cathode as the second water flow rate based on the electroosmotic drag coefficient; and subtract the second water flow rate from the first water flow rate to obtain the water flow rate entering the anode from the cathode.

[0111] In some embodiments, an acquisition module is used to calculate the saturated vapor pressure at the anode outlet corresponding to the second temperature value at the anode outlet of the fuel cell; the ratio of the saturated vapor pressure at the anode outlet to the second pressure value at the anode outlet of the fuel cell is used as the proportion of saturated water vapor in the anode outlet gas, and the anode outlet gas includes saturated water vapor, anode outlet hydrogen and anode outlet nitrogen; the saturated water vapor flow rate at the anode outlet of the fuel cell is obtained according to the sum and proportion of the flow rates of the anode outlet hydrogen and the anode outlet nitrogen; the flow rate of the anode outlet hydrogen is the sum of the reflux hydrogen flow rate at the anode outlet of the fuel cell and the hydrogen flow rate discharged through the exhaust valve of the fuel cell; the flow rate of the anode outlet nitrogen is the sum of the reflux nitrogen flow rate at the anode outlet of the fuel cell and the nitrogen flow rate discharged through the exhaust valve.

[0112] In summary, the drainage control device of the fuel cell proposed in the embodiment of the present application obtains in real time the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell, and calculates the water flow that will become liquid water at the anode outlet of the fuel cell by combining the total water flow generated by the fuel cell under the current power generation state and the saturated vapor flow at the anode outlet of the fuel cell. The opening time of the drain valve is adjusted with reference to the water flow of the liquid water so that the adjusted opening time can match the current power generation state of the fuel cell, and the liquid water generated in this state is discharged to the outside, thereby improving the accuracy of drainage control.

[0113] The specific definition of the drainage control device of the fuel cell can be found in the definition of the drainage control method of the fuel cell mentioned above, which will not be repeated here. Each module in the drainage control device of the fuel cell can be implemented in whole or in part by software, hardware and a combination thereof. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0114] In one embodiment, Fig.10 As shown, a fuel cell system 1000 is provided, including a fuel cell operation support system 1001 and a control system 1002, the fuel cell operation support system 1001 and the control system 1002 are connected, and the control system 1002 is used to execute the above Figure 2-Figure 8 The steps of the fuel cell drainage control method are shown.

[0115] In one embodiment, if Fig.11 As shown, a vehicle 1100 is provided, including Fig.10 A fuel cell system 1000 is shown.

[0116] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the drainage control method of the fuel cell in the above embodiment is implemented, for example Figure 2 S201-S203 as shown, or Figures 3 to 8 Alternatively, when the computer program is executed by the processor, the functions of each module / unit in the embodiment of the drainage control device for the fuel cell are realized, for example Fig. 9 The functions of the acquisition module, calculation module and control module shown are not described here in detail to avoid repetition. The computer-readable storage medium may be non-volatile or volatile.

[0117] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0118] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0119] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A fuel cell drainage control method, characterized in that: The method comprises: Real-time acquisition of the gaseous water flow at the anode inlet of the fuel cell, the water flow entering the anode from the cathode, and the saturated water vapor flow at the anode outlet of the fuel cell; Obtaining the flow rate of liquid water at the anode outlet of the fuel cell according to the gaseous water flow rate, the water flow rate from the cathode to the anode and the saturated water vapor flow rate; The opening time of the fuel cell drain valve is adjusted according to the water flow rate of the liquid water, so that the drain valve is opened to drain water at the adjusted opening time.

2. The method according to claim 1, characterized in that The step of adjusting the opening time of the fuel cell drain valve according to the water flow rate of the liquid water comprises: Determining whether the flow rate of the liquid water is greater than a preset threshold; If it is greater than, determining the maximum water storage time of the gas-water separator according to the water flow rate of the liquid water and the maximum water storage capacity of the gas-water separator of the fuel cell; The opening time of the drain valve is adjusted according to the maximum water storage time.

3. The method according to claim 1, characterized in that After adjusting the opening time of the fuel cell drain valve according to the water flow rate of the liquid water, the method further includes: Obtaining an inlet pressure value of the drain valve; Obtaining the drainage flow of the drainage valve corresponding to the inlet pressure value; The single opening time of the drain valve is determined according to the water flow of the liquid water, the adjusted opening time and the drainage flow of the drain valve, so as to open the drain valve according to the single opening time.

4. The method according to any one of claims 1 to 3, characterized in that: The real-time acquisition of the gaseous water flow rate at the anode inlet of the fuel cell comprises: Acquire in real time a first temperature value of the anode inlet of the fuel cell, a first pressure value of the anode inlet of the fuel cell, and a current value of the fuel cell; Acquiring the humidity of the anode inlet of the fuel cell; Calculate the total target gas flow at the anode inlet of the fuel cell according to the current value, wherein the total target gas flow is the sum of the flow rates of other gases except the gaseous water flow rate; Calculating the anode inlet saturated vapor pressure corresponding to the first temperature value; The product of the saturated vapor pressure at the anode inlet and the humidity is divided by the first pressure value to obtain the volume ratio of gaseous water at the anode inlet; The gaseous water flow rate is calculated according to the volume proportion of the gaseous water at the anode inlet and the total flow rate of the target gas.

5. The method according to claim 4, characterized in that The step of calculating the target total gas flow rate at the anode inlet of the fuel cell according to the current value comprises: Calculating the dry hydrogen flow rate and the reflux hydrogen flow rate at the anode inlet of the fuel cell according to the current value; Calculating the reflux nitrogen flow rate at the anode inlet of the fuel cell according to the reflux hydrogen flow rate and a preset ratio value, wherein the preset ratio value is the ratio of the hydrogen flow rate to the total flow rate of hydrogen and nitrogen gas in the reflux gas at the anode inlet of the fuel cell; The sum of the dry hydrogen flow rate, the reflux hydrogen flow rate and the reflux nitrogen flow rate is taken as the total flow rate of the target gas.

6. The method according to any one of claims 1 to 3, characterized in that: Real-time acquisition of the water flow from the cathode to the anode includes: Acquire in real time a second temperature value of the fuel cell anode outlet and a second pressure value of the fuel cell anode outlet; Acquire the water content in the membrane corresponding to the second temperature value, the second pressure value and the humidity at the anode inlet of the fuel cell, and the concentration gradient of the water content in the membrane, wherein the water content in the membrane is the water content in the membrane of the proton exchange membrane in the fuel cell; Obtaining a diffusion rate corresponding to the water content in the membrane and the second temperature value, wherein the diffusion rate is a diffusion rate of water in the proton exchange membrane; Determining, according to the diffusion rate and the concentration gradient, a water flow rate diffusing from the cathode into the anode as a first water flow rate; Obtaining an electroosmotic drag coefficient corresponding to the water content in the membrane, wherein the electroosmotic drag coefficient is the electroosmotic drag coefficient of the proton exchange membrane; Determining, according to the electroosmotic drag coefficient, a water flow rate electroosmotically dragged from the anode to the cathode as a second water flow rate; The water flow rate from the cathode to the anode is obtained by subtracting the second water flow rate from the first water flow rate.

7. The method according to any one of claims 1 to 3, characterized in that: Real-time acquisition of the saturated water vapor flow rate at the anode outlet of the fuel cell includes: Calculating the anode outlet saturated vapor pressure corresponding to the second temperature value at the anode outlet of the fuel cell; The ratio of the anode outlet saturated vapor pressure to the second pressure value at the anode outlet of the fuel cell is used as the proportion of saturated water vapor in the anode outlet gas, wherein the anode outlet gas includes the saturated water vapor, anode outlet hydrogen and anode outlet nitrogen; Obtaining a saturated water vapor flow rate at an anode outlet of the fuel cell according to the sum of the flow rate of the hydrogen at the anode outlet and the flow rate of the nitrogen at the anode outlet and the proportion; The flow rate of hydrogen at the anode outlet is the sum of the flow rate of reflux hydrogen at the anode outlet of the fuel cell and the flow rate of hydrogen discharged through the exhaust valve of the fuel cell; The flow rate of the nitrogen at the anode outlet is the sum of the flow rate of the reflux nitrogen at the anode outlet of the fuel cell and the flow rate of the nitrogen exhausted through the exhaust valve.

8. A drainage control device for a fuel cell, characterized in that: The device comprises: An acquisition module is used to acquire in real time the gaseous water flow rate at the anode inlet of the fuel cell, the water flow rate entering the anode from the cathode, and the saturated water vapor flow rate at the anode outlet of the fuel cell; A calculation module, used for obtaining the flow rate of liquid water at the anode outlet of the fuel cell according to the gaseous water flow rate, the water flow rate entering the anode from the cathode and the saturated water vapor flow rate; The control module is used to adjust the opening time of the fuel cell drain valve according to the water flow of the liquid water, so as to open the drain valve to drain water at the adjusted opening time.

9. A fuel cell system, characterized in that: include: An operation support system and a control system for a fuel cell, wherein the operation support system for the fuel cell is connected to the control system, and the control system is used to execute the steps of the drainage control method for the fuel cell as claimed in any one of claims 1 to 7.

10. A vehicle, characterized in that: A fuel cell system comprising the fuel cell system of claim 9.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the fuel cell drainage control method according to any one of claims 1 to 7 are implemented.

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