Fuel cell vehicle, controller, and thermal management method and device thereof

Abstract

The present invention discloses a fuel cell vehicle, a controller, and a thermal management method and device thereof. The method includes: obtaining the stack voltage, stack inlet temperature, stack outlet temperature, and vehicle demand power of the fuel cell system; determining the target output power of the fuel cell system according to the stack voltage, the stack inlet temperature, and the vehicle demand power, and determining the first required heat dissipation amount of the stack coolant according to the target output power; determining the second required heat dissipation amount of the stack coolant according to the stack inlet temperature and the stack outlet temperature; determining the larger value of the first required heat dissipation amount and the second required heat dissipation amount as the target required heat dissipation amount of the stack coolant; and controlling the coolant flow rate of the fuel cell system according to the target required heat dissipation amount. The above method can improve the control accuracy of fuel cell thermal management.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cell vehicles, and particularly to a fuel cell vehicle, a controller, and a thermal management method and device thereof. Background Art

[0002] As an important part of new energy vehicles, fuel cell vehicles have developed rapidly in recent years. The thermal management of fuel cells is one of the important factors affecting the performance of fuel cell vehicles. How to keep the fuel cell in a suitable reaction temperature range during actual application has become an urgent problem to be solved.

[0003] Currently, the conventional method for thermal management of fuel cell systems is to detect the inlet water temperature and outlet water temperature of the stack, and then adjust the rotation speed of the cooling water pump according to the temperature difference between the outlet water temperature and the inlet water temperature of the stack. The problems of this method are as follows: By controlling the pump speed through the inlet and outlet temperatures, due to the delay in heat transfer from the battery reaction to the cooling water, the thermal management control will lag, and the dynamic control effect is poor; at the same time, under the dynamic response and high vehicle speed conditions of the fuel cell, the cooling water temperature fluctuates greatly, which will also affect the operation stability of the fuel cell. Summary of the Invention

[0004] The present invention provides a fuel cell vehicle, a controller, and a thermal management method and device thereof to solve or partially solve the technical problem of poor control effect of the fuel cell thermal management of fuel cell vehicles currently.

[0005] To solve the above technical problem, in a first aspect, according to an embodiment of the present invention, a thermal management method for a fuel cell vehicle is provided, which is applied to a fuel cell controller. The method includes:

[0006] Obtain the stack voltage, stack inlet temperature, stack outlet temperature, and vehicle demand power of the fuel cell system;

[0007] Determine the target output power of the fuel cell system according to the stack voltage, the stack inlet temperature, and the vehicle demand power, and determine the first required heat dissipation of the stack coolant according to the target output power;

[0008] Determine the second required heat dissipation of the stack coolant according to the stack inlet temperature and the stack outlet temperature;

[0009] Determine the larger value of the first required heat dissipation and the second required heat dissipation as the target required heat dissipation of the stack coolant;

[0010] Control the coolant flow rate of the fuel cell system according to the target required heat dissipation.

[0011] Optionally, determining the target output power of the fuel cell system according to the stack voltage, the stack inlet temperature, and the vehicle demand power includes:

[0012] Determining a first power output limit of the fuel cell system according to the stack voltage;

[0013] Determining a second power output limit of the fuel cell system according to the stack inlet temperature;

[0014] Determining the minimum value among the first power output limit, the second power output limit, and the vehicle demand power as the target output power.

[0015] Optionally, determining the first power output limit of the fuel cell system according to the stack voltage includes:

[0016] Determining a stack attenuation coefficient of the fuel cell system according to the stack voltage;

[0017] Correcting the stack inlet temperature according to the stack attenuation coefficient to obtain a corrected inlet temperature;

[0018] Determining the first power output limit according to the stack attenuation coefficient and the corrected inlet temperature.

[0019] Optionally, determining the stack attenuation coefficient of the fuel cell system according to the stack voltage includes:

[0020] Obtaining the current output power of the fuel cell stack;

[0021] Obtaining a reference voltage of the fuel cell stack at the current output power;

[0022] Determining the stack attenuation coefficient according to the difference between the reference voltage and the stack voltage and the current output power.

[0023] Optionally, determining the second required heat dissipation of the stack coolant according to the stack inlet temperature and the stack outlet temperature includes:

[0024] Determining the second required heat dissipation according to the corrected inlet temperature and the stack outlet temperature.

[0025] Optionally, determining the second required heat dissipation of the stack coolant according to the stack inlet temperature and the stack outlet temperature includes:

[0026] Determining a first calculated heat dissipation of the stack coolant according to the stack outlet temperature;

[0027] Determine the second calculated heat dissipation of the fuel cell coolant according to the difference between the outlet temperature and the inlet temperature of the fuel cell stack;

[0028] Determine the second required heat dissipation according to the first calculated heat dissipation and the second calculated heat dissipation.

[0029] Optionally, the method further includes:

[0030] Obtain the ambient temperature and the current vehicle speed of the vehicle;

[0031] Determine the natural wind heat dissipation according to the ambient temperature and the current vehicle speed;

[0032] Determine the third required heat dissipation according to the inlet temperature of the fuel cell stack;

[0033] Determine the fan required heat dissipation according to the third required heat dissipation and the natural wind heat dissipation;

[0034] Determine the target speed of the cooling fan according to the fan required heat dissipation, and control the cooling fan to operate according to the target speed.

[0035] Based on the same inventive concept, in a second aspect, according to an embodiment of the present invention, a control device for heat management of a fuel cell vehicle is provided, which is applied to a fuel cell controller and includes:

[0036] An acquisition module, configured to acquire the stack voltage, the inlet temperature of the fuel cell stack, the outlet temperature of the fuel cell stack, and the vehicle demand power of the fuel cell system;

[0037] A first determination module, configured to determine the target output power of the fuel cell system according to the stack voltage, the inlet temperature of the fuel cell stack, and the vehicle demand power, and determine the first required heat dissipation of the fuel cell coolant according to the target output power;

[0038] A second determination module, configured to determine the second required heat dissipation of the fuel cell coolant according to the inlet temperature and the outlet temperature of the fuel cell stack;

[0039] A third determination module, configured to determine the larger value between the first required heat dissipation and the second required heat dissipation as the target required heat dissipation of the fuel cell coolant;

[0040] A control module, configured to control the coolant flow rate of the fuel cell system according to the target required heat dissipation.

[0041] Based on the same inventive concept, in a third aspect, according to an embodiment of the present invention, a fuel cell controller is provided. The fuel cell controller includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the method according to any one of the first aspects are implemented.

[0042] Based on the same inventive concept, in a fourth aspect, according to an embodiment of the present invention, a fuel cell vehicle is provided. The fuel cell system of the fuel cell vehicle includes the fuel cell controller provided in the third aspect.

[0043] Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0044] The present invention provides a thermal management method for a fuel cell vehicle. The target output power of the fuel cell system is determined according to the stack voltage, the stack inlet temperature, and the vehicle demand power. Then, the first required heat dissipation amount of the coolant is determined according to the target output power. Then, in combination with the second required heat dissipation amount determined by the stack outlet temperature and the inlet temperature, the larger value is determined as the target required heat dissipation amount of the coolant, and the flow rate of the coolant is controlled based on the target required heat dissipation amount. The above method introduces a mechanism for determining the heat dissipation demand of the fuel cell according to the demand power during thermal management, so that the stack heat dissipation of the fuel cell is controlled in combination with the demand power, the stack outlet temperature, and the inlet temperature, solving the problem of lag in heat management and poor dynamic control effect caused by the lag of the temperature change of the coolant at the inlet and outlet of the stack behind the change of the fuel cell output power; at the same time, determining the coolant flow rate in combination with the demand power can also avoid the problem of reduced operating stability of the fuel cell caused by large fluctuations in coolant temperature. The combination of the above two aspects improves the control accuracy of fuel cell thermal management.

[0045] The above description is only an overview of the technical solutions of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present invention more obvious and understandable, the following specific embodiments of the present invention are specifically exemplified. Description of the Drawings

[0046] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components.

[0047] In the drawings:

[0048] Figure 1 A flowchart showing the thermal management method according to an embodiment of the present invention is shown;

[0049] Figure 2 Shows the architecture diagram of a fuel cell system according to an embodiment of the present invention;

[0050] Figure 3 Shows the logic control schematic diagram of a thermal management method according to an embodiment of the present invention;

[0051] Figure 4 Shows the schematic diagram of a thermal management device according to an embodiment of the present invention;

[0052] Figure 5 Shows the schematic diagram of a fuel cell controller according to an embodiment of the present invention. Detailed implementation manners

[0053] In order to enable those skilled in the art in the technical field to which the present application belongs to more clearly understand the present application, the technical solutions of the present application will be described in detail below with reference to the accompanying drawings through specific embodiments. Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as the general understanding of those skilled in the art to which the present invention belongs. In case of conflict, this specification prevails. Unless otherwise specifically stated, various devices and the like used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0054] In order to solve the problems of control lag and poor accuracy caused by adjusting the cooling water only according to the stack outlet temperature and the stack inlet temperature in the prior art, in an optional embodiment, a thermal management method for a fuel cell vehicle is provided, which is applied to a fuel cell controller; as Figure 1 shown, the method includes steps S101 to S105, specifically as follows:

[0055] S101: Obtain the stack voltage, stack inlet temperature, stack outlet temperature and vehicle demand power of the fuel cell system;

[0056] Specifically, the stack inlet temperature is the temperature of the stack coolant at the stack inlet, denoted as T1; the coolant, as the cooling medium of the fuel cell, often uses cooling water, and other types of cooling liquid media can also be used.

[0057] Similarly, the stack outlet temperature is the temperature of the stack coolant at the stack outlet, denoted as T2;

[0058] The stack voltage is the currently detected output voltage of the fuel cell stack.

[0059] The vehicle demand power is the demand power calculated and output by the vehicle control unit (VCU) of the fuel cell vehicle according to the current driving condition of the vehicle, denoted as W2.

[0060] S102: Determine the target output power of the fuel cell system according to the stack voltage, the stack inlet temperature and the vehicle demand power, and determine the first required heat dissipation amount of the stack coolant according to the target output power.

[0061] The first required heat dissipation amount is the heat dissipation amount that needs to be taken away by the coolant and is associated with the output power of the vehicle. By combining the vehicle demand power with the stack voltage and the stack inlet temperature, a more accurate output power is determined, and then the required heat dissipation amount matching it is determined according to this output power.

[0062] Among them, an optional scheme for determining the target output power is as follows:

[0063] Determine the first power output limit of the fuel cell system according to the stack voltage; determine the second power output limit of the fuel cell system according to the stack inlet temperature; determine the minimum value among the first power output limit, the second power output limit and the vehicle demand power as the target output power.

[0064] Specifically, the first power output limit is the maximum power that the fuel cell stack can output under the current stack voltage, denoted as W0. A corresponding table between the stack voltage and the maximum output power can be obtained from the fuel cell supplier, and then according to the current stack voltage, the corresponding first power output limit can be queried from this table.

[0065] The second power output limit is the maximum power that the fuel cell stack can output under the limitation of the current stack inlet temperature, denoted as W1. The second power output limit reflects the influence of the temperature of the coolant when entering the stack on the power peak that the stack can output. According to the detected stack inlet temperature, the corresponding second power output limit can be calculated using existing algorithms.

[0066] After obtaining W0, W1, W2, according to W 目标 = min[W0, W1, W2] to determine the target output power, and the target output power is also called the power generation power of the fuel cell system.

[0067] Next, according to the target output power W 目标 Determine the first required heat dissipation amount Q1 of the stack coolant. The first required heat dissipation amount represents the heat of the stack that needs to be taken away by the coolant system, and can be determined by the following formula:

[0068] Q1 = (A × b H2_emis × W 目标 × hm ) / 3600 (1)

[0069] In the above formula:

[0070] A is the percentage of the heat transferred to the coolant system in the fuel heat energy, which is a known constant;

[0071] b H2_emis is the hydrogen emission of the current fuel cell system, with the unit of kg / (kW·h);

[0072] W 目标 is the target output power or power generation power, with the unit of kW;

[0073] h m is the low calorific value of hydrogen fuel, with the unit of kJ / kg, which is a known constant.

[0074] S103: Determine the second required heat dissipation of the fuel cell stack coolant according to the stack inlet temperature and the stack outlet temperature;

[0075] The second required heat dissipation is the heat dissipation determined according to the stack outlet temperature T2 and the stack inlet temperature T1 of the coolant. The second required heat dissipation Q2 can be directly calculated by the following formula based on the temperature difference between the stack outlet temperature and the stack inlet temperature:

[0076] Q2 = C f × M fuel × ΔT; (2)

[0077] In the above formula, C f refers to the specific heat capacity of the coolant; M fuel is the coolant flow rate through the fuel cell stack; ΔT = T2 - T1.

[0078] In order to increase the second required heat dissipation, this embodiment provides another determination scheme, which is as follows:

[0079] Determine the first calculated heat dissipation Q calc1 of the fuel cell stack coolant according to the stack outlet temperature; determine the second calculated heat dissipation Q calc2 of the fuel cell stack coolant according to the difference between the stack outlet temperature and the stack inlet temperature; determine the second required heat dissipation Q2 according to the first calculated heat dissipation Q calc1 and the second calculated heat dissipation Q calc2 .

[0080] Specifically, the first calculated heat dissipation Q calc1 is calculated by the following formula:

[0081] Q calc1 = C f × M fuel×ΔT2; (3)

[0082] In the above formula:

[0083] C f refers to the specific heat capacity of the coolant; M fuel is the coolant flow rate passing through the fuel cell stack;

[0084] ΔT2 = T 21 -T 20 , T 21 is the outlet temperature of the stack at the current data acquisition moment, and T 20 is the outlet temperature of the stack at the previous data acquisition moment.

[0085] The second calculated heat dissipation Q calc2 is calculated using Equation (2).

[0086] Next, according to Q2 = max[Q calc1 , Q calc2 , that is, the larger value of the two is taken as the second required heat dissipation.

[0087] S104: Determine the target required heat dissipation of the coolant for the stack as the larger value between the first required heat dissipation and the second required heat dissipation;

[0088] Specifically, the first required heat dissipation is the heat dissipation obtained based on the required power, and the second required heat dissipation is the heat dissipation obtained based on the inlet and outlet temperatures of the coolant. The larger value between the two is taken as the target required heat dissipation. The reason for this processing is that: the change in water temperature lags behind the change in the output power of the fuel cell to a certain extent. During the loading stage of the fuel cell, the first required heat dissipation calculated based on the output power of the fuel cell is more accurate; while during the load reduction of the fuel cell, the second required heat dissipation calculated based on the temperature difference between the inlet and outlet of the coolant is more accurate. During the loading stage, the value of the first required heat dissipation is greater than the second required heat dissipation, and during the load reduction stage, the value of the second required heat dissipation is greater than the first required heat dissipation. Therefore, the larger value Q m of the heat dissipation requirements Q1 and Q2 is taken as the heat dissipation capacity that the current coolant system needs to provide, that is, the target required heat dissipation.

[0089] S105: Control the coolant flow rate of the fuel cell system according to the target required heat dissipation.

[0090] After obtaining the target required heat dissipation Q m , the corresponding target coolant flow rate can be determined according to the existing algorithm, and then by adjusting the valve opening of the coolant system and the rotation speed of the cooling pump, the actual flow rate of the coolant entering the fuel cell stack for cooling can be made to match the target coolant flow rate, thereby controlling the internal reaction temperature of the stack to be appropriate.

[0091] This embodiment provides a thermal management method for a fuel cell vehicle. The target output power of the fuel cell system is determined according to the stack voltage, the stack inlet temperature, and the vehicle demand power. Then, the first required heat dissipation of the coolant is determined based on the target output power. Next, the second required heat dissipation determined by combining the stack outlet temperature and the inlet temperature is used to determine the larger value as the target required heat dissipation of the coolant. The flow rate of the coolant is controlled based on the target required heat dissipation. The above method introduces a mechanism for determining the heat dissipation requirement of the fuel cell according to the demand power during thermal management, enabling the stack heat dissipation of the fuel cell to be controlled by combining the demand power with the stack outlet temperature and the inlet temperature, solving the problem of lag in heat management and poor dynamic control effect caused by the lag in the temperature change of the coolant at the inlet and outlet of the stack behind the change in the output power of the fuel cell. At the same time, determining the coolant flow rate in combination with the demand power can also avoid the problem of reduced operating stability of the fuel cell caused by large fluctuations in the coolant temperature. The combination of the above two aspects improves the control accuracy of fuel cell thermal management together.

[0092] Further research has found that as the operating time of the stack increases, the performance of the stack deteriorates, and the requirements for temperature operating conditions become more stringent. If the stack performance degradation is not considered, the failure rate of the fuel cell stack in the later stage will be significantly higher.

[0093] To solve this problem, in some alternative embodiments, a stack degradation coefficient is introduced to correct the first power output limit and the stack inlet temperature, as follows:

[0094] According to the stack voltage, determine the stack degradation coefficient of the fuel cell system.

[0095] Specifically, the stack degradation coefficient represents the degree of performance degradation of a fuel cell stack after being used for a period of time compared with a new fuel cell stack under the same output power. By conducting a fuel cell degradation performance calibration test on the fuel cell system bench, the mapping relationship between the stack output power, the stack voltage, and the stack degradation coefficient is determined and stored in advance. Then, according to the currently collected stack voltage, the corresponding stack degradation coefficient can be determined by using a two-dimensional map look-up method. An exemplary structure of the mapping relationship is shown in Table 1:

[0096] Table 1: Map mapping table of stack degradation coefficient

[0097]

[0098] In Table 1, Stack-volt represents the difference between the output voltage of a fuel cell that has been used for a period of time at the current output power and the output voltage of a brand-new fuel cell at the same output power. The table rows represent the output power, and the blank cells are the corresponding values of the stack degradation coefficient. Since the stack degradation coefficient is calibrated based on the stack degradation performance experiment and has different values for fuel cell stacks of different types and provided by different manufacturers, Table 1 does not impose specific restrictions on the stack degradation coefficient.

[0099] Therefore, the scheme for determining the stack degradation coefficient based on Table 1 is as follows:

[0100] Obtain the current output power of the fuel cell stack; obtain the reference voltage of the fuel cell stack at the current output power; determine the stack degradation coefficient according to the difference between the reference voltage and the stack voltage and the current output power. Specifically, according to the difference and the current output power, query Table 1 to obtain the corresponding stack degradation coefficient r.

[0101] Next, correct the stack inlet temperature according to the stack degradation coefficient to obtain the corrected inlet temperature.

[0102] Specifically, the correction relationship or mapping table between the stack degradation coefficient and the stack inlet temperature can be pre-calibrated in the fuel cell degradation performance calibration test, and then according to the current stack inlet temperature and the current stack degradation coefficient, the corrected inlet temperature can be obtained by calculation or by looking up the table. Within the reasonable degradation range of the stack, as the stack degrades, it is necessary to appropriately increase the stack inlet temperature.

[0103] Then, determine the first power output limit according to the stack degradation coefficient and the corrected inlet temperature.

[0104] Similarly, in the fuel cell degradation performance calibration test, pre-calibrate the mapping table of the stack degradation coefficient, the stack inlet temperature, and the first power output limit and store it in the memory of the fuel cell controller. Then, in actual application, according to the current stack degradation coefficient and the corrected inlet temperature, query the two-dimensional map table to obtain the corresponding first power output limit. The mapping table has the form shown in Table 2:

[0105] Table 2: Mapping table of the first power output limit, the stack degradation coefficient, and the stack inlet temperature

[0106]

[0107] In Table 2, the column header is the stack attenuation coefficient, where 1 means that the stack performance / voltage has not been attenuated, 0.9 means that the stack performance / voltage has been attenuated by 10%, and so on; the row header is the stack inlet temperature or the corrected inlet temperature, and the value in the cell is the corresponding first power output limit W0. Since W0 is calibrated in the stack attenuation performance experiment, it has different values for fuel cell stacks of different types and manufacturers, so Table 2 does not make specific restrictions on it.

[0108] Since the stack inlet temperature has been corrected by the stack attenuation coefficient, the corrected inlet temperature and the stack outlet temperature can be used to determine the second required heat dissipation, and the calculation formula is shown in formula (2).

[0109] The above embodiments take into account the thermal management control logic of the coolant system of the fuel cell system, and the fuel cell system is usually equipped with a fan for air cooling. Therefore, in some optional embodiments, the thermal management method further includes the control logic of the fan, which is as follows:

[0110] Obtain the ambient temperature and the current speed of the vehicle; determine the natural wind heat dissipation according to the ambient temperature and the current speed; determine the third required heat dissipation according to the stack inlet temperature; determine the fan required heat dissipation according to the third required heat dissipation and the natural wind heat dissipation; determine the target speed of the cooling fan according to the fan required heat dissipation, and control the cooling fan to operate according to the target speed.

[0111] Specifically, the ambient temperature indicates the current atmospheric temperature outside the vehicle. According to the principle of convective heat transfer, the fuel cell system can calculate the heat dissipation of natural wind through natural wind heat exchange based on the ambient temperature and the current vehicle speed. It can be understood that if the ambient temperature is lower and the vehicle speed is higher, the efficiency of fuel cell cooling and heat dissipation will be higher, and the fuel cell stack will have a lower demand for fan heat dissipation.

[0112] The third required heat dissipation represents the heat that can be removed by air convection, and its determination method is as follows:

[0113] Q3=C f ×M fuel ×ΔT1; (4)

[0114] In the above formula:

[0115] C f Refers to the specific heat capacity of the coolant; M fuel is the coolant flow through the fuel cell stack;

[0116] ΔT1=T 11 -T 10 , T 11 is the stack inlet temperature at the current data collection time, T 10is the inlet temperature of the fuel cell stack at the previous data acquisition moment.

[0117] Subtracting the natural wind heat dissipation from the third demand heat dissipation can obtain the heat that needs to be dissipated by turning on the cooling fan, that is, the fan demand heat dissipation Q x . After obtaining the fan demand heat dissipation, the target speed of the cooling fan can be determined to control the cooling fan for heat dissipation.

[0118] To more intuitively illustrate the technical solution provided by the above embodiments, in the following embodiment, a certain fuel cell system that adopts the solution provided in the above embodiments is taken as an example for illustration. Figure 2 shows the thermal management architecture diagram of the fuel cell system. The fuel cell system uses water as the coolant. The schematic diagram of the thermal management control logic of the fuel cell system is as Figure 3 shown, and the control process is as follows:

[0119] S1: The fuel cell controller (FCCU) receives the start command sent by the vehicle controller (VCU) and controls the start of the fuel cell system;

[0120] S2: The FCCU detects the environmental temperature, the vehicle speed of the vehicle, the stack voltage, the inlet temperature T1 of the fuel cell stack, and the outlet temperature T2 of the fuel cell stack at this moment;

[0121] S3: The FCCU calculates the stack attenuation coefficient r according to the stack voltage;

[0122] S4: The FCCU uses the stack attenuation coefficient r to correct the inlet temperature T1 of the fuel cell stack;

[0123] S5: The FCCU determines the maximum power that can be generated by the fuel cell stack in the current state according to the stack attenuation coefficient r and the corrected inlet temperature, that is, the first power output limit W0;

[0124] S6: The FCCU calculates the third demand heat dissipation Q3 according to the inlet temperature T of the fuel cell stack detected at the current moment 11 and the temperature T at the previous moment 10 , that is, the heat dissipation required for the fuel cell stack to maintain the inlet temperature. This part of the heat dissipation is achieved by air cooling;

[0125] S7: The FCCU calculates the no-fan heat dissipation capacity (the heat dissipated by natural wind convection) according to the environmental temperature and vehicle speed, and corrects the fan demand heat dissipation Qx that needs to be executed by the fan,

[0126] S8: The FCCU determines the target speed of the cooling fan through the fan demand heat dissipation Qx and controls the cooling fan for heat dissipation;

[0127] S9: The FCCU calculates the maximum power that the fuel cell can execute at the current temperature, i.e., the second power output limit W1, based on the corrected stack inlet temperature T1.

[0128] S10: The FCCU receives the requested power from the VCU, i.e., the vehicle demand power W2.

[0129] S11: The FCCU determines the power generation power of the current stack, i.e., the target output power W 目标 to be the minimum value among W0, W1, and W2.

[0130] S12: The FCCU calculates the first required heat dissipation Q1 at this output power based on W 目标 .

[0131] S13: The FCCU calculates the heat dissipation Q using Equation (3) based on the stack outlet temperature T2 calc1 ;

[0132] S14: The FCCU calculates the difference ΔT between the stack outlet temperature T2 and the corrected stack inlet temperature T1.

[0133] S15: Using this temperature difference ΔT, the second calculated heat dissipation Q is determined using Equation (2) calc2 ;

[0134] S16: Take the larger value of Q calc1 and Q calc2 as the second required heat dissipation Q2.

[0135] S17: Since the change in the cooling water temperature lags behind the change in the fuel cell output power to a certain extent, when the fuel cell is loaded, the heat dissipation demand needs to be calculated based on the fuel cell output power. When the fuel cell is unloaded, the heat dissipation demand needs to be determined based on the temperature difference between the stack inlet and outlet. Therefore, take the larger value of the first required heat dissipation Q1 and the second required heat dissipation Q2 as the heat dissipation cooling water flow rate that the current water pump needs to provide, i.e., the target required heat dissipation Q of the cooling water m .

[0136] S18: The FCCU adjusts the size of the three-way valve and the speed of the water pump according to Q m to change the cooling water flow rate into the stack of the fuel cell system, thereby controlling the reaction temperature inside the stack to be appropriate.

[0137] It should be noted that the serial numbers S1 to S18 of the above steps are for convenient description in combination with Figure 3 and do not represent a limitation on the execution time sequence of the above steps.

[0138] The thermal management method of the fuel cell system provided in this embodiment has the following characteristics:

[0139] 1) Without increasing costs, considering the rate of heat transfer, a mechanism for determining the heat dissipation requirements of a fuel cell based on the required power is introduced. By comprehensively considering the output power of the fuel cell and the temperature difference between the inlet and outlet of the stack, the current target heat dissipation requirement of the fuel cell system is determined, and the cooling water flow rate is adjusted accordingly. This solves the problem of lag in heat management and poor dynamic control effect caused by the lag in the temperature change of the coolant at the inlet and outlet of the stack behind the change in the output power of the fuel cell, and also avoids the problem of reduced operating stability of the fuel cell caused by large fluctuations in the coolant temperature. Therefore, the accuracy of heat management can be improved, the reaction temperature in the fuel cell stack can be maintained within a good range under both loading and unloading conditions, the working efficiency can be enhanced, and the working stability of the fuel cell can be increased.

[0140] 2) Considering the influence of stack performance degradation on stack thermal management, the stack decay coefficient is calculated based on the stack voltage, and the stack inlet temperature T1 (i.e., the operating temperature of the stack) and the first power output limit W0 are corrected using the stack decay coefficient, further improving the accuracy of heat management, reducing the failure rate of the fuel cell, and ensuring long-term trouble-free operation of the fuel cell.

[0141] Based on the same inventive concept as the foregoing embodiments, in another alternative embodiment, as Figure 4 shown, a control device for heat management of a fuel cell vehicle is provided, which is applied to a fuel cell controller and includes:

[0142] An acquisition module 401, configured to acquire the stack voltage, stack inlet temperature, stack outlet temperature, and vehicle demand power of the fuel cell system;

[0143] A first determination module 402, configured to determine the target output power of the fuel cell system according to the stack voltage, the stack inlet temperature, and the vehicle demand power, and determine the first required heat dissipation of the stack coolant according to the target output power;

[0144] A second determination module 403, configured to determine the second required heat dissipation of the stack coolant according to the stack inlet temperature and the stack outlet temperature;

[0145] A third determination module 404, configured to determine the larger value of the first required heat dissipation and the second required heat dissipation as the target required heat dissipation of the stack coolant;

[0146] A control module 405, configured to control the coolant flow rate of the fuel cell system according to the target required heat dissipation.

[0147] Optionally, the first determination module 402 is configured to:

[0148] Determine a first power output limit of the fuel cell system according to the stack voltage;

[0149] Determine a second power output limit of the fuel cell system according to the stack inlet temperature;

[0150] Determine the minimum value among the first power output limit, the second power output limit, and the vehicle demand power as the target output power.

[0151] Further, the first determination module 402 is configured to:

[0152] Determine a stack attenuation coefficient of the fuel cell system according to the stack voltage;

[0153] Correct the stack inlet temperature according to the stack attenuation coefficient to obtain a corrected inlet temperature;

[0154] Determine the first power output limit according to the stack attenuation coefficient and the corrected inlet temperature.

[0155] Further, the first determination module 402 is configured to:

[0156] Obtain the current output power of the fuel cell stack;

[0157] Obtain the reference voltage of the fuel cell stack at the current output power;

[0158] Determine the stack attenuation coefficient according to the difference between the reference voltage and the stack voltage and the current output power.

[0159] Optionally, the second determination module 403 is configured to:

[0160] Determine the second required heat dissipation amount according to the corrected inlet temperature and the stack outlet temperature.

[0161] Optionally, the second determination module 403 is configured to:

[0162] Determine a first calculated heat dissipation amount of the stack coolant according to the stack outlet temperature;

[0163] Determine a second calculated heat dissipation amount of the stack coolant according to the difference between the stack outlet temperature and the stack inlet temperature;

[0164] Determine the second required heat dissipation amount according to the first calculated heat dissipation amount and the second calculated heat dissipation amount.

[0165] Optionally, the acquisition module 401 is configured to:

[0166] Obtain the ambient temperature and the current vehicle speed of the vehicle;

[0167] The device further includes a fourth determination module, configured to:

[0168] Determine the natural wind heat dissipation amount according to the ambient temperature and the current vehicle speed;

[0169] Determine the third required heat dissipation amount according to the stack inlet temperature;

[0170] Determine the fan required heat dissipation amount according to the third required heat dissipation amount and the natural wind heat dissipation amount;

[0171] Determine the target rotation speed of the cooling fan according to the fan required heat dissipation amount, and control the cooling fan to operate according to the target rotation speed.

[0172] Based on the same inventive concept as the foregoing embodiments, in another alternative embodiment, as Figure 5 shown, a fuel cell controller 500 is provided, including a processor 520 and a memory 510. The memory 510 is coupled to the processor 520. The memory 510 stores a computer program 511. When the computer program 511 is executed by the processor 520, the fuel cell controller 500 executes the steps of the method in the foregoing embodiments.

[0173] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0174] The present invention provides a fuel cell vehicle, a controller, and a thermal management method and device thereof. The method therein determines the target output power of the fuel cell system according to the stack voltage, the stack inlet temperature, and the vehicle demand power, then determines the first required heat dissipation amount of the coolant according to the target output power, and then combines the second required heat dissipation amount determined by the stack outlet temperature and the inlet temperature, and determines the target required heat dissipation amount of the coolant as the larger value among them, and controls the flow rate of the coolant based on the target required heat dissipation amount. The above method introduces a mechanism for determining the heat dissipation demand of the fuel cell according to the demand power during thermal management, so that the stack heat dissipation of the fuel cell is controlled by combining the demand power and the stack outlet temperature and the inlet temperature, and solves the problem of lag in heat management and poor dynamic control effect caused by the temperature change of the coolant at the inlet and outlet of the stack lagging behind the change of the fuel cell output power; at the same time, combining the demand power to determine the coolant flow rate can also avoid the problem of reduced operating stability of the fuel cell caused by large fluctuations in the coolant temperature. The combination of the above two aspects jointly improves the control accuracy of fuel cell thermal management.

[0175] Although the preferred embodiments of the present application have been described, additional changes and modifications can be made to these embodiments by those of ordinary skill in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0176] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A thermal management method for a fuel cell vehicle, characterized in that, Applied to a fuel cell controller, the method includes: Obtaining the stack voltage, stack coolant inlet temperature, stack coolant outlet temperature, and vehicle demand power of a fuel cell system; Determining the target output power of the fuel cell system according to the stack voltage, the stack coolant inlet temperature, and the vehicle demand power, and determining the first required heat dissipation of the stack coolant according to the target output power; Determining the second required heat dissipation of the stack coolant according to the stack coolant inlet temperature and the stack coolant outlet temperature; Determining the larger value of the first required heat dissipation and the second required heat dissipation as the target required heat dissipation of the stack coolant; Controlling the coolant flow rate of the fuel cell system according to the target required heat dissipation.

2. The method according to claim 1, wherein The determining the target output power of the fuel cell system according to the stack voltage, the stack coolant inlet temperature, and the vehicle demand power includes: Determining the first power output limit of the fuel cell system according to the stack voltage; Determining the second power output limit of the fuel cell system according to the stack coolant inlet temperature; Determining the minimum value among the first power output limit, the second power output limit, and the vehicle demand power as the target output power.

3. The method according to claim 2, characterized in that, The determining the first power output limit of the fuel cell system according to the stack voltage includes: Determining the stack attenuation coefficient of the fuel cell system according to the stack voltage; Correcting the stack coolant inlet temperature according to the stack attenuation coefficient to obtain a corrected coolant inlet temperature; Determining the first power output limit according to the stack attenuation coefficient and the corrected coolant inlet temperature.

4. The method according to claim 3, wherein The determining the stack attenuation coefficient of the fuel cell system according to the stack voltage includes: Obtaining the current output power of the fuel cell stack; Obtaining the reference voltage of the fuel cell stack at the current output power; Determining the stack attenuation coefficient according to the difference between the reference voltage and the stack voltage and the current output power.

5. The method according to claim 3, wherein The determining the second required heat dissipation of the stack coolant according to the stack coolant inlet temperature and the stack coolant outlet temperature includes: Determining the second required heat dissipation according to the corrected coolant inlet temperature and the stack coolant outlet temperature.

6. The method according to claim 1, characterized in that, The determining the second required heat dissipation of the stack coolant according to the stack coolant inlet temperature and the stack coolant outlet temperature includes: Determining the first calculated heat dissipation of the stack coolant according to the stack coolant outlet temperature; Determining the second calculated heat dissipation of the stack coolant according to the difference between the stack coolant outlet temperature and the stack coolant inlet temperature; Determining the second required heat dissipation according to the first calculated heat dissipation and the second calculated heat dissipation.

7. The method according to claim 1, wherein It further includes: Obtaining the ambient temperature and the current vehicle speed of the vehicle; Determining the natural wind heat dissipation according to the ambient temperature and the current vehicle speed; Determining the third required heat dissipation according to the stack coolant inlet temperature; Determine the heat dissipation requirement of the fan according to the third required heat dissipation and the natural wind heat dissipation; Determine the target speed of the cooling fan according to the heat dissipation requirement of the fan, and control the cooling fan to operate according to the target speed.

8. A thermal management device for a fuel cell vehicle, characterized in that, Applied to a fuel cell controller, the device includes: An acquisition module, configured to acquire the stack voltage, the inlet temperature of the stack coolant, the outlet temperature of the stack coolant, and the vehicle demand power of the fuel cell system; A first determination module, configured to determine the target output power of the fuel cell system according to the stack voltage, the inlet temperature of the stack coolant, and the vehicle demand power, and determine the first required heat dissipation of the stack coolant according to the target output power; A second determination module, configured to determine the second required heat dissipation of the stack coolant according to the inlet temperature of the stack coolant and the outlet temperature of the stack coolant; A third determination module, configured to determine the larger value of the first required heat dissipation and the second required heat dissipation as the target required heat dissipation of the stack coolant; A control module, configured to control the coolant flow rate of the fuel cell system according to the target required heat dissipation.

9. A fuel cell controller, the fuel cell controller comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A fuel cell vehicle, characterized in that, The fuel cell system of the fuel cell vehicle includes the fuel cell controller according to claim 9.

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