Fuel cell variable load control method, device and storage medium

Abstract

The application discloses a fuel cell variable load control method, device and storage medium. The control method comprises the following steps: obtaining the real-time temperature of the fuel cell during the variable load process of the fuel cell; determining the voltage upper limit value corresponding to the current temperature based on a preset temperature and voltage upper limit value mapping relationship, wherein the preset temperature and voltage upper limit value mapping relationship is configured such that the voltage upper limit value decreases with the increase of the temperature; and controlling the real-time voltage of the fuel cell to be not higher than the voltage upper limit value during the variable load process of the fuel cell. The fuel cell variable load control method, device and storage medium provided by the application aim to reduce the attenuation rate of the fuel cell during variable load at high temperature, thereby prolonging the service life of the fuel cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cells, in particular to a fuel cell variable load control method, device and storage medium. BACKGROUND

[0002] Proton exchange membrane fuel cell (PEMFC) is the most common fuel cell technology for vehicles, which is mainly composed of proton exchange membrane, anode and cathode catalyst layer, gas diffusion layer and bipolar plate. The function of the proton membrane is to conduct protons, isolate electrons and isolate anode and cathode reactants, the anode and cathode catalyst layer is the place for electrochemical reaction, the gas diffusion layer mainly determines the transmission of reaction gas and the discharge of liquid water, and the function of the bipolar plate is to isolate the reactants and the coolant. The reaction principle is that hydrogen is decomposed into protons and electrons under the action of anode catalyst, protons move to the cathode catalyst through the proton membrane and the polymer on the catalyst surface, and electrons generate electricity through the external circuit and move to the cathode catalyst to react with protons and oxygen to generate water.

[0003] Durability is one of the important factors to be considered for vehicle fuel cell application, one of the main reasons affecting durability is that the catalyst is dissolved and grown due to voltage cycling during variable load, which reduces the electrochemical effective reaction area and causes irreversible performance degradation and failure. At the same time, due to the current trend of heavy-duty fuel cell power, the heat dissipation demand of high-power fuel cell system increases sharply, which leads to a higher operating temperature of high-power operation, exceeding 85℃ or even 90℃. With the increase of operating temperature, the catalyst degradation rate caused by voltage cycling increases when the load is reduced, and the service life is significantly reduced, so the durability problem caused by voltage cycling at high temperature gradually becomes a bottleneck restricting the service life of fuel cell, so it is urgent to find a suitable way to prolong the service life under high temperature variable load conditions, so as to meet the use demand of high-power heavy-duty fuel cell.

[0004] Therefore, it is necessary to provide a technical scheme to overcome the shortcomings of the prior art. SUMMARY

[0005] In order to overcome the defects of the prior art, the present application provides a fuel cell variable load control method, device and storage medium, which aims to reduce the degradation rate of fuel cell under high temperature variable load, so as to prolong its service life.

[0006] The present application is realized by the following technical scheme: a fuel cell variable load control method, the control method comprises:

[0007] During the variable load process of the fuel cell, the real-time temperature of the fuel cell is obtained;

[0008] The preset temperature and voltage upper limit value mapping relationship is configured such that the voltage upper limit value decreases with the increase of temperature.

[0009] In the variable load process of the fuel cell, the real-time voltage of the fuel cell is controlled to be not higher than the voltage upper limit value.

[0010] As a further improved technical solution, the preset temperature and voltage upper limit value mapping relationship is configured such that, in the variable load process of the fuel cell, the decay rate when the fuel cell operates at the voltage upper limit value corresponding to any temperature is equivalent.

[0011] As a further improved technical solution, the preset temperature and voltage upper limit value mapping relationship is established by the following method:

[0012] Obtain a curve graph of the decay rate of the fuel cell varying with voltage at multiple temperatures;

[0013] Determine the voltage values corresponding to the multiple temperatures at a set decay rate as the voltage upper limit values to establish the mapping relationship.

[0014] As a further improved technical solution, the set decay rate is the decay rate of the fuel cell under the condition of a reference temperature and a reference voltage, wherein the reference temperature is taken from 75℃ to 85℃, and the reference voltage is taken from 0.8V to 0.9V.

[0015] As a further improved technical solution, controlling the real-time voltage of the fuel cell to be not higher than the voltage upper limit value comprises:

[0016] According to the voltage-current characteristic curve of the fuel cell, determine the current lower limit value corresponding to the voltage upper limit value;

[0017] In the variable load process of the fuel cell, the actual current of the fuel cell is controlled to be not lower than the current lower limit value.

[0018] As a further improved technical solution, in the variable load process of the fuel cell,

[0019] If the theoretical current value calculated according to the target power is lower than the current lower limit value, the fuel cell is controlled to have the current lower limit value as the actual current;

[0020] If the theoretical current value calculated according to the target power is not lower than the current lower limit value, the fuel cell is controlled to have the theoretical current value as the actual current.

[0021] As a further improved technical solution, the variable load includes load reduction, and the load reduction process comprises:

[0022] Initial following stage: the real-time voltage of the fuel cell rises but is less than the upper voltage limit value corresponding to the current temperature, and the real-time power of the fuel cell follows the target power;

[0023] Power deviation stage: the real-time voltage of the fuel cell is controlled to be the upper voltage limit value corresponding to the current temperature, the actual current of the fuel cell is greater than the theoretical current value corresponding to the target power, and the real-time power of the fuel cell is higher than the target power;

[0024] Complete following stage: the temperature of the fuel cell decreases, the real-time voltage of the fuel cell is less than the upper voltage limit value corresponding to the current temperature, and the real-time power of the fuel cell follows the target power.

[0025] As a further improved technical solution, the duration of the power deviation stage is not greater than 15s.

[0026] The application is also implemented by the following technical solution: a fuel cell variable load control device for implementing the control method described above, the control device comprising:

[0027] A temperature detection unit for detecting the real-time temperature of the fuel cell;

[0028] A voltage upper limit acquisition unit for determining the upper voltage limit value corresponding to the current temperature based on a preset temperature and voltage upper limit value mapping relationship when receiving a fuel cell variable load instruction;

[0029] A control unit for controlling the real-time voltage of the fuel cell to be not greater than the voltage upper limit value during the variable load process.

[0030] The application is also implemented by the following technical solution: a storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the variable load control method described above.

[0031] The fuel cell variable load control method provided by the application solves the problem of insufficient service life caused by the rapid decay of high-power vehicle-mounted fuel cells under high-temperature variable load conditions by introducing a dynamic voltage upper limit control strategy based on temperature. At the same time, by using the application, the braking recovery during load reduction is not affected when the fuel cell is reduced at a relatively low temperature, although there is some impact when the fuel cell is reduced at a relatively high temperature, but the impact time is short, the deviation is small, and the impact on the response of the whole vehicle power is small; thereby the method not only effectively prolongs the service life of the battery, but also balances the service life and performance, the control strategy has little effect on the whole vehicle and has high engineering feasibility, has significant technical progress and wide industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a schematic diagram of the decay rate changing with temperature under the conventional variable load mode.

[0033] Figure 2 Fig. 2 is a schematic diagram of the change of the decay rate with voltage in the conventional variable load mode.

[0034] Figure 3 Fig. 4 is a schematic diagram of the normalized decay degree of the variable load at different voltages and temperatures in an embodiment of the present application.

[0035] Figure 4 Fig. 5 is a mapping relationship between the temperature and the voltage upper limit value in an embodiment of the present application.

[0036] Figure 5 Fig. 6 is a current-power characteristic curve of a fuel cell.

[0037] Figure 6 Fig. 7 is a voltage-current characteristic curve of a fuel cell.

[0038] Figure 7 Fig. 8 is a diagram of the change of various parameters in the load reduction process in an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to have a more clear understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0041] The present application relates to the technical field of fuel cells, in particular to a fuel cell variable load control method, device and storage medium, aiming to reduce the decay rate of the fuel cell variable load at high temperature, so as to prolong the service life thereof.

[0042] Please refer to Figures 1 to 7 As shown in Fig. 1, the present application provides a fuel cell variable load control method, which comprises: obtaining the real-time temperature of the fuel cell in the variable load process of the fuel cell; determining the voltage upper limit value corresponding to the current temperature based on a preset temperature-voltage upper limit value mapping relationship, wherein the preset temperature-voltage upper limit value mapping relationship is configured such that the voltage upper limit value decreases with the increase of the temperature; and controlling the real-time voltage of the fuel cell not to exceed the voltage upper limit value in the variable load process of the fuel cell.

[0043] The fuel cell variable load control method provided by the application solves the problem of insufficient service life caused by too fast attenuation of a high-power vehicle-mounted fuel cell under high-temperature variable load conditions by introducing a dynamic voltage upper limit control strategy based on temperature. Meanwhile, when the fuel cell is under load reduction at a relatively low temperature, the braking recovery during load reduction is not affected, and although there is a certain impact when the fuel cell is under load reduction at a relatively high temperature, the impact is short in time, small in deviation, and has little effect on the response of the vehicle power. Therefore, the method not only effectively prolongs the service life of the battery, but also balances the service life and performance, has little effect on the vehicle, has high engineering feasibility, and has significant technical progress and wide industrial application value.

[0044] The core of the control method is to dynamically adjust the voltage upper limit value according to the real-time temperature during the fuel cell variable load process to achieve protection of the service life of the fuel cell. Specifically, the control method includes the following steps: first, during the fuel cell variable load process, the real-time temperature of the fuel cell is obtained by a detection device such as a temperature sensor. This step is the basis for subsequent control, ensuring that the control strategy can respond to the actual working state of the fuel cell. Then, based on a preset temperature and voltage upper limit value mapping relationship, the voltage upper limit value corresponding to the current temperature is determined. This mapping relationship is specially configured such that the voltage upper limit value decreases with the increase of the temperature, and this amount of relationship is established based on in-depth research on the attenuation characteristics of the fuel cell. Finally, during the variable load process of the fuel cell, the real-time voltage of the fuel cell is controlled by a corresponding control unit to be less than the voltage upper limit value. Through these steps, effective protection of the fuel cell under variable load conditions, especially under high-temperature conditions, is achieved.

[0045] In this embodiment, the preset temperature and voltage upper limit value mapping relationship is further configured such that the attenuation rate of the fuel cell when running at the voltage upper limit value corresponding to any temperature during the fuel cell variable load process is equivalent. In other words, when the fuel cell is controlled to vary load based on the preset temperature and voltage upper limit value mapping relationship, the attenuation degree of the fuel cell when varying load at different temperatures is the same or basically consistent. This configuration embodies the core idea of the application, that is, by adjusting the voltage upper limit to compensate for the influence of temperature change on the attenuation rate, the attenuation degree of the fuel cell when varying load at different temperatures is kept within a relatively stable and acceptable range, thereby overall guaranteeing the service life of the fuel cell. The technical effect brought by this technical means is significant, which enables the fuel cell system to maintain consistent life expectancy within a wide temperature range, improving the reliability of system design and the predictability of service life.

[0046] In some embodiments, the preset temperature and voltage upper limit value mapping relationship is established by: obtaining a curve of the decay rate of the fuel cell varying with voltage at multiple temperatures; determining the voltage value corresponding to the multiple temperatures at a set decay rate as the voltage upper limit value, so as to establish the mapping relationship.

[0047] Specifically, as shown in Figure 1 , the decay rate increases with the increase of temperature during load change, and the increasing rate increases with temperature, so that the load change at high temperature will significantly reduce the service life. Meanwhile, as shown in Figure 2 , the decay rate decreases with the decrease of voltage during load change, so that the load change at high temperature can reduce the voltage during load change, so that the combined effect of temperature and voltage on the decay rate is smaller. In order to keep the decay rate of the fuel cell consistent during load change at any temperature, the embodiment of the present application establishes a quantitative relationship between the temperature and voltage upper limit and the durability decay rate during the voltage cycle durability process. In actual use, by the equivalent decay rate principle, the voltage upper limit during load change is reduced with the increase of load change temperature, so as to meet the service life requirement. Of course, in some embodiments, the decay rate during load change at different temperatures can also be controlled to be inconsistent on the premise of meeting the service life requirement. In short, by establishing a quantitative relationship between the temperature and voltage upper limit and the durability decay rate, the decay rate during load change at high temperature can be reduced compared with the conventional load change process without voltage upper limit control.

[0048] In establishing the preset temperature and voltage upper limit value mapping relationship, a systematic method can be used. Specifically, first, a curve of the decay rate of the fuel cell varying with voltage at multiple temperatures is obtained. These curves can be obtained by laboratory durability test, reflecting the decay characteristics of the fuel cell under different working conditions. Then, the voltage value corresponding to the multiple temperatures at a set decay rate is determined as the voltage upper limit value, so as to establish the mapping relationship. This establishment process ensures the scientificity and reliability of the mapping relationship, and provides accurate data basis for subsequent control. The beneficial effect brought by this technical means is that the setting of the voltage upper limit value has a clear scientific basis, rather than an empirical estimate, thereby improving the effectiveness and precision of the control strategy.

[0049] Further, the set attenuation rate is an attenuation rate of the fuel cell under a reference temperature and a reference voltage, wherein the reference temperature is taken from 75℃ to 85℃, and the reference voltage is taken from 0.8V to 0.9V. Selecting the reference condition in this range has practical engineering significance, because these conditions represent the operating state of the fuel cell under typical working conditions, and thus taking them as the reference can ensure the applicability of the control strategy in practical applications. The technical effect brought by this technical choice is that the life protection strategy can be matched with the actual use requirements of the fuel cell, neither affecting the performance due to over-protection, nor shortening the life due to insufficient protection. For example, in an embodiment, it is known through durability experiments that the service life of the fuel cell can meet the requirements under, for example, an upper limit voltage of 80℃ and 0.85V, and thus this can be taken as the reference, i.e., the reference temperature is 80℃ and the reference voltage is 0.85V. Meanwhile, as shown in Figure 3 , it is a normalized attenuation degree diagram under different voltages and temperatures, wherein 80℃ and 0.85V are taken as the reference point, and the normalized attenuation degree corresponding to this point is set to 1, and then the voltage values corresponding to the attenuation degree of 1 on the curves of 95℃, 90℃ and 85℃ can be determined as the upper limit values of the voltage at these temperatures. Thus, the upper limit values of the voltage at different temperatures can be obtained as shown in Figure 4 , and the controller can obtain the dynamic upper limit value of the voltage by looking up the curve through the temperature sensor when the fuel cell is under load, and control the voltage when the fuel cell is under load according to the upper limit value of the voltage, so as to ensure the service life when the fuel cell is under load at high temperature.

[0050] In the embodiment, controlling the real-time voltage of the fuel cell not to exceed the upper limit value of the voltage includes: determining a lower limit value of the current corresponding to the upper limit value of the voltage according to the voltage-current characteristic curve of the fuel cell; and controlling the actual current of the fuel cell not to be lower than the lower limit value of the current during the load change of the fuel cell.

[0051] As shown in Figures 5 to 7 , in the specific implementation of controlling the real-time voltage of the fuel cell not to exceed the upper limit value of the voltage, an indirect control mode can be adopted. Specifically, a lower limit value of the current corresponding to the upper limit value of the voltage is determined according to the voltage-current characteristic curve of the fuel cell, and then the actual current of the fuel cell is controlled not to be lower than the lower limit value of the current during the load change of the fuel cell. Since there is a determined corresponding relationship between the voltage and the current of the fuel cell, by controlling the current not to be lower than a certain lower limit value, the voltage can be indirectly ensured not to exceed the corresponding upper limit value. The implementation effect of this technical means lies in that it makes full use of the existing control architecture of the fuel cell system, and the control of the current is usually more direct and accurate, so that the control strategy of the present application can be conveniently integrated into the existing system, thereby improving the engineering feasibility of the scheme.

[0052] In the specific current control strategy, the specific operation is as follows: in the process of load change of the fuel cell, if the theoretical current value calculated according to the target power is lower than the current lower limit value, the fuel cell is controlled to take the current lower limit value as the actual current; if the theoretical current value calculated according to the target power is not lower than the current lower limit value, the fuel cell is controlled to take the theoretical current value as the actual current. This hierarchical control strategy ensures that the power demand is tracked as accurately as possible on the premise of guaranteeing the service life. When the theoretical current is lower than the current lower limit, the service life protection is given priority, and although a power tracking deviation is generated at this time, this is a necessary compromise for protecting the fuel cell, and since the tracking deviation is short in time and small in amount, the influence on the performance of the fuel cell is small; when the theoretical current is not lower than the current lower limit, the power demand can be perfectly tracked. The technical effect brought by this intelligent trade-off strategy is that the power demand and the service life protection requirement can be met at the same time in most working conditions, and only a slight compromise needs to be made in a few extreme working conditions, thereby realizing the best balance between performance and service life.

[0053] Further, the load change of the fuel cell includes load reduction and load increase. As shown in Figure 7 In an embodiment, the load reduction process includes three stages, which are described as follows. Initial following stage: the real-time voltage of the fuel cell rises but is less than the voltage upper limit value corresponding to the current temperature, and the real-time power of the fuel cell follows the target power; power deviation stage: the real-time voltage of the fuel cell is controlled to be the voltage upper limit value corresponding to the current temperature, the actual current of the fuel cell is greater than the theoretical current value corresponding to the target power, and the real-time power of the fuel cell is higher than the target power; complete following stage: the temperature of the fuel cell decreases, the real-time voltage of the fuel cell is less than the voltage upper limit value corresponding to the current temperature, and the real-time power of the fuel cell follows the target power. This clear process division clearly shows the dynamic adjustment characteristics of the control strategy of the application, and the technical effect is that the realization of the service life protection target is ensured, and the power tracking deviation is controlled within a limited period of time, and the influence on the system performance is minimized.

[0054] In general control, the duration of the power deviation stage is generally not more than 15 seconds, ensuring that the power deviation will not have a significant impact on the performance of the vehicle. The short-term power deviation is within an acceptable range, and the service life protection benefit obtained thereby is significant. This technical choice brings the beneficial effect of achieving a good balance between engineering practicability and technical advancement, so that the technical solution of the application can be truly applied.

[0055] Specifically, as shown in Figure 7 At t1, the controller receives the demand for load reduction of the vehicle power. Since the fuel cell system responds to power by controlling the current, the controller needs to determine the current control strategy according to the target power and the current lower limit value, and the current control strategy is determined as follows. When the target power is lower than the current lower limit value, the current lower limit value is taken as the actual current; when the target power is not lower than the current lower limit value, the theoretical current value corresponding to the target power is taken as the actual current. The controller controls the fuel cell to take the actual current as the current value at t2, and the fuel cell system responds to the load reduction demand of the vehicle power. Figure 5The power and current curve shown is used to obtain Figure 7 the theoretical current curve in FIG. 6 as the current control target value. Meanwhile, for the consideration of service life, the average voltage upper limit is obtained as the voltage upper limit value according to the temperature-voltage upper limit value curve shown in FIG. 7, and the current lower limit value is obtained according to the fuel cell current-voltage curve shown in FIG. 8. Figure 4 Figure 6 Figure 7

[0056] At t1 to t2, since the actual average voltage is lower than the average voltage upper limit, the theoretical current is greater than the current lower limit value at this time, so the actual current can follow the theoretical current to decrease, realizing the follow-up of the target power. At t2 to t3, due to the hysteresis of the water temperature drop, the theoretical current is less than the current lower limit value at this time, so the actual current cannot follow the theoretical current to decrease, and can only follow the current lower limit value to decrease, resulting in that the actual current is greater than the theoretical current, so that the actual power at this time is greater than the target power, and a certain tracking deviation will be generated. But soon with the decrease of the water temperature, the average voltage upper limit increases continuously, the current lower limit value decreases continuously, gradually approaches the theoretical current, so that the actual power gradually approaches the target power. When reaching t3, the current lower limit value is lower than the theoretical current, and the actual current can completely follow the theoretical current, thereby realizing the complete follow-up of the target power, and finally realizing the complete load reduction process. In the entire load reduction process, although the output power is higher than the demand of the whole vehicle in the short time period of t2 to t3, since the time length is relatively short, about 8s in the embodiment and the deviation amount is small, so it has no influence on the whole vehicle, but it has a significant improvement on prolonging the service life of the fuel cell.

[0057] The application further provides a fuel cell variable load control device for realizing the control method as described above. The control device comprises: a temperature detection unit for detecting the real-time temperature of the fuel cell; a voltage upper limit acquisition unit for determining the voltage upper limit value corresponding to the current temperature based on the preset temperature and voltage upper limit value mapping relationship when receiving the fuel cell variable load instruction; and a control unit for controlling the real-time voltage of the fuel cell not to exceed the voltage upper limit value in the variable load process.

[0058] The control device comprises a temperature detection unit for detecting the real-time temperature of the fuel cell. The voltage upper limit acquisition unit determines the voltage upper limit value corresponding to the current temperature based on the preset temperature and voltage upper limit value mapping relationship when receiving the fuel cell variable load instruction. The control unit controls the real-time voltage of the fuel cell not to exceed the voltage upper limit value in the variable load process. These functional units can be integrated in the existing controller of the fuel cell system, or can be realized as an independent control module.

[0059] ​​​The temperature detection unit can include temperature sensors arranged at appropriate positions of the fuel cell stack, which can accurately and quickly detect the operating temperature of the fuel cell. In an embodiment, the temperature detected is the temperature of the fuel cell stack; of course, it can be understood that the temperature of other parts can also be detected, and the temperature of the stack can be indirectly obtained based on the relationship between the part and the stack. The voltage upper limit acquisition unit can include a memory and a processor, the memory stores a mapping relationship table of the temperature and the voltage upper limit value, and the processor queries the table to obtain the corresponding voltage upper limit value according to the received temperature signal. In some embodiments, the temperature and voltage upper limit value mapping relationship can be stored in the memory of the control system in the form of a two-dimensional data table. In actual control process, the controller quickly obtains the voltage upper limit value corresponding to the current temperature by table lookup method. This implementation has small calculation amount, fast response speed, and is suitable for application in real-time control system. As an alternative, the mapping relationship can also exist in the form of a mathematical function, and the controller calculates the corresponding voltage upper limit value by substituting the temperature value. This way saves storage space and facilitates online adjustment of parameters. The control unit adjusts the operating parameters of the fuel cell to realize voltage limitation according to the obtained voltage upper limit value. The technical effect of this modular design is to improve the reliability and maintainability of the system, and each functional unit performs its own function and works cooperatively.

[0060] In the vehicle application scenario, the control device of the application effectively communicates with the control system of the whole vehicle. The control device can be software, hardware or a combination of software and hardware embedded in the control system of the whole vehicle. The vehicle controller sends a power demand instruction to the fuel cell system, and the fuel cell control system executes the power regulation while implementing the life protection strategy based on the technical solution of the application to ensure that the service life of the fuel cell is maximized while meeting the power demand of the vehicle.

[0061] In order to further improve the intelligent level of the system, the control device can further include a self-learning unit for optimizing and adjusting the temperature and voltage upper limit value mapping relationship according to the actual degradation of the fuel cell. This adaptive ability enables the control system to adapt to the performance changes of the fuel cell during its life cycle and always maintain the optimal protection effect. Considering the differences between individual fuel cells and the performance degradation during use, the mapping relationship can be designed to be adjustable. The control system can regularly detect the actual degradation of the fuel cell and adjust the parameters in the mapping relationship accordingly to maintain the consistency of the life protection effect. This adaptive ability further improves the practical value of the technical solution of the application.

[0062] The application further provides a storage medium, which stores a computer program, and the computer program is executed by a processor to implement the variable load control method according to any one of the technical solutions. The storage medium can be a read-only memory, a random access memory, a flash memory, a hard disk, or various forms of storage devices.

[0063] It can be seen from the above detailed description of the specific embodiments that the fuel cell variable load control method, device and storage medium provided by the application effectively solve the technical problem of too fast life attenuation of the fuel cell under high-temperature variable load conditions by introducing the dynamic voltage upper limit control based on temperature. Meanwhile, the brake recovery during load reduction is not affected when the fuel cell is reduced at a relatively low temperature, although there is a certain impact when the fuel cell is reduced at a relatively high temperature, the impact time is short, the deviation is small, and the impact on the response of the whole vehicle power is small; therefore, the method not only effectively prolongs the battery life, but also balances the life and performance, the control strategy has little impact on the whole vehicle and has high engineering feasibility, and exhibits significant technical progress and practical industrial application value.

[0064] The application is described by several specific embodiments, and those skilled in the art should understand that various transformations and equivalent replacements can be made to the application without departing from the scope of the application. In addition, various modifications can be made to the application for specific situations or specific conditions without departing from the scope of the application. Therefore, the application is not limited to the disclosed specific embodiments, but should include all the embodiments falling within the scope of the claims of the application.

Claims

1. A fuel cell load-varying control method, characterized in that, The control method includes: During the variable load process of the fuel cell, the real-time temperature of the fuel cell is obtained; Based on a preset mapping relationship between temperature and voltage upper limit, the upper limit of voltage corresponding to the current temperature is determined, wherein the preset mapping relationship between temperature and voltage upper limit is configured such that the upper limit of voltage decreases as the temperature increases; During the variable load process of the fuel cell, the real-time voltage of the fuel cell is controlled to not exceed the upper voltage limit. The preset temperature and voltage upper limit mapping relationship is configured such that during fuel cell load variation, the fuel cell operates at the voltage upper limit corresponding to any temperature with a similar rate of decay. The preset mapping relationship between temperature and voltage upper limit values ​​is established in the following way: Obtain graphs showing the degradation rate of a fuel cell as a function of voltage at multiple temperatures; The voltage values ​​corresponding to the multiple temperatures at the set decay rate are determined as the upper limit voltage value to establish the mapping relationship.

2. The fuel cell load control method as described in claim 1, characterized in that, The set decay rate is the decay rate of the fuel cell under reference temperature and reference voltage conditions, wherein the reference temperature is taken from 75℃ to 85℃ and the reference voltage is taken from 0.8V to 0.9V.

3. The fuel cell load control method as described in claim 1, characterized in that, Controlling the real-time voltage of the fuel cell to not exceed the upper voltage limit includes: Based on the voltage-current characteristic curve of the fuel cell, determine the lower current limit corresponding to the upper voltage value; During the variable load process of the fuel cell, the actual current of the fuel cell is controlled to be no lower than the lower current limit value.

4. The fuel cell load control method as described in claim 3, characterized in that, During fuel cell load variation processes If the theoretical current value calculated based on the target power is lower than the lower current limit, then the fuel cell is controlled to use the lower current limit as the actual current. If the theoretical current value calculated based on the target power is not lower than the lower limit of the current, then the fuel cell is controlled to use the theoretical current value as the actual current.

5. The fuel cell load variation control method according to any one of claims 1 to 4, characterized in that, The load change includes load reduction, and the load reduction process includes: Initial follow-up phase: The real-time voltage of the fuel cell rises but is less than the upper limit of voltage corresponding to the current temperature, and the real-time power of the fuel cell follows the target power; Power deviation stage: The real-time voltage of the fuel cell is controlled to the upper limit of the voltage corresponding to the current temperature, the actual current of the fuel cell is greater than the theoretical current value corresponding to the target power, and the real-time power of the fuel cell is higher than the target power. Fully follow stage: As the temperature of the fuel cell decreases, the real-time voltage of the fuel cell is lower than the upper limit of the voltage corresponding to the current temperature, and the real-time power of the fuel cell follows the target power.

6. The fuel cell load variation control method as described in claim 5, characterized in that, The duration of the power deviation phase shall not exceed 15 seconds.

7. A fuel cell load-varying control device for implementing the control method as described in any one of claims 1 to 6, characterized in that, The control device includes: Temperature detection unit, used to detect the real-time temperature of fuel cell; When the voltage upper limit acquisition unit receives the fuel cell load change command, it determines the voltage upper limit value corresponding to the current temperature based on the preset mapping relationship between temperature and voltage upper limit value. The control unit controls the real-time voltage of the fuel cell to not exceed the upper voltage limit during load changes.

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the variable load control method as described in any one of claims 1 to 6.

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