Power battery anti-overcharge method and system of fuel cell vehicle and vehicle

Abstract

The invention provides a power battery anti-overcharge method and system of a fuel cell automobile and a vehicle, and the power battery anti-overcharge method of the fuel cell automobile comprises the steps: judging whether a power battery has an overcharge risk or not based on the working condition of the whole automobile and the real-time state of the power battery; if the overcharge risk exists, controlling the fuel cell system to reduce the output power; if the output power is reduced to the lowest stable operation power and the net output power is still higher than the current allowable maximum charging power of the power battery, the fuel cell system is controlled to enter a self-consumption mode, and the electric energy generated by the fuel cell system is guided to an internal auxiliary machine for auxiliary consumption; and maintaining the net output power not to be greater than the current allowable maximum charging power. The overcharge risk when the charging capacity of the battery is reduced due to low temperature or energy recovery is effectively solved, direct shutdown is replaced by intelligent hierarchical control, the start-stop frequency of the fuel battery is remarkably reduced, the service life of the fuel battery is prolonged, and the economical efficiency of the whole vehicle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell vehicles, in particular to a power battery overcharge prevention method, system and vehicle for fuel cell vehicles. BACKGROUND

[0002] Hydrogen fuel cell vehicles have entered the commercial demonstration operation stage due to their clean and pollution-free advantages. Due to the soft output characteristics and slow dynamic response of fuel cells, existing fuel cell vehicles usually adopt a hybrid driving configuration of fuel cells and power batteries. Among them, the power battery can directly provide power for the vehicle, and the fuel cell converts the chemical energy of hydrogen into electrical energy, which can drive the vehicle and charge the power battery.

[0003] In order to improve the service life of the fuel cell and reduce the high potential attenuation, the fuel cell system is usually provided with a minimum output power limit, especially in high-power systems, the minimum output power value is high. This leads to that when the power battery is closed due to low temperature or abnormal conditions, if the output power of the fuel cell continues to be greater than the demand power of the vehicle, the excess power will charge the power battery, which may cause the power battery to be overcharged, especially in low-power conditions such as vehicle idling, the risk is more significant.

[0004] In the prior art, in order to prevent overcharging, the method of directly shutting down the fuel cell system is often used. However, frequent start-stop and the accompanying purging process will reduce the service life of the fuel cell, affect the reliability and economy of the system. Therefore, there is an urgent need for a control method that can effectively prevent the power battery from being overcharged while reducing the number of unnecessary start-stop of the fuel cell system. SUMMARY

[0005] The embodiments of the present application provide a power battery overcharge prevention method, system and vehicle for fuel cell vehicles, to solve the technical problem of frequent start-stop of the system caused by the strategy of directly shutting down the fuel cell in the prior art to prevent overcharging, thereby shortening the service life of the fuel cell.

[0006] In a first aspect, a power battery overcharge prevention method for a fuel cell vehicle is provided, which includes: judging whether the power battery has an overcharge risk based on the vehicle operating conditions and the real-time state of the power battery; if there is an overcharge risk, controlling the fuel cell system to reduce the output power; If the net output power is still higher than the current maximum allowable charging power of the power battery after the output power is reduced to the minimum stable running power, the fuel cell system is controlled to enter a self-consumption mode, and the electrical energy generated by the fuel cell system is guided to the internal auxiliary machine for auxiliary consumption, so that the net output power is maintained to be not greater than the current maximum allowable charging power.

[0007] In some embodiments, based on the real-time state of the vehicle and the power battery, it is determined whether the power battery has overcharging risk, which includes the following steps: The battery management system calculates and sends the current maximum allowed charging power to the vehicle controller based on the temperature, state of charge and state of health of the power battery; The vehicle controller obtains the current net output power of the fuel cell system and the vehicle demand power; If the difference between the output power of the fuel cell system and the vehicle demand power is greater than the current maximum allowed charging power, and the duration exceeds the first preset time threshold, it is determined that there is an overcharging risk.

[0008] In some embodiments, the output power of the fuel cell system is controlled to be reduced, which includes the following steps: When the output power of the fuel cell system is reduced to its minimum stable operating power, it is determined whether the current maximum allowed charging power is less than the minimum stable operating power; if it is less, the output power of the fuel cell system is continuously reduced until the output power of the fuel cell system is less than the current maximum allowed charging power.

[0009] In some embodiments, the output power of the fuel cell system is controlled to be reduced by a preset power gradient value; wherein the preset power gradient value is adjusted according to the difference between the current maximum allowed charging power and the current net output power, and the greater the difference, the greater the preset power gradient value.

[0010] In some embodiments, the electrical energy generated by the fuel cell system is guided to the internal auxiliary machine for auxiliary consumption, which includes the following steps: Based on the pressure of the stack and the flow demand, the speed of the air compressor is closed-loop controlled to increase the power consumption of the air compressor and reduce the net output power of the fuel cell system.

[0011] In some embodiments, the auxiliary energy consumption further includes the following steps: On the basis of the active energy consumption of the air compressor, the PTC heater in the high-pressure cooling circuit is started simultaneously, and the cooling fan is adjusted to the highest gear operation.

[0012] In some embodiments, to ensure the safety of the fuel cell, before entering the self-consumption mode, the following steps are further included: The fuel cell controller confirms that the operating parameters of the fuel cell are in a stable interval, and sends a mode switching ready signal to the vehicle controller; After receiving the confirmation instruction, the vehicle controller performs the switching operation of the self-consumption mode.

[0013] In some embodiments, exit and recovery steps are further included, which include the following steps: When the current allowable maximum charging power is restored to be higher than the minimum stable operation power and lasts for a second preset time threshold, the vehicle controller sends an exit self-consumption mode instruction to the fuel cell controller; The fuel cell controller controls the fuel cell system to increase the net output power at a preset recovery gradient and synchronously reduce the auxiliary machine additional power consumption until the system recovers to the normal power response state. During the recovery process, the vehicle controller continuously monitors whether the power battery has overcharging risk.

[0014] In a second aspect, the application further provides a power battery overcharge prevention system of a fuel cell vehicle, which comprises: A monitoring and judging module is configured to judge whether the power battery has overcharging risk based on the real-time state of the power battery and the vehicle working condition; if the power battery has overcharging risk, the fuel cell system is controlled to reduce the output power; A control module is configured to, if the net output power is still higher than the current allowable maximum charging power of the power battery after the output power is reduced to the minimum stable operation power, control the fuel cell system to enter the self-consumption mode, guide the electric energy generated by the fuel cell system to the internal auxiliary machine for auxiliary consumption, and maintain the net output power of the fuel cell system to be not greater than the current allowable maximum charging power.

[0015] In a third aspect, the application further provides a vehicle comprising the power battery overcharge prevention system of the fuel cell vehicle.

[0016] The technical scheme provided by the application has the following beneficial effects: The power battery overcharge prevention method of the fuel cell vehicle provided by the embodiments of the application replaces the rough power switch with fine power adjustment and mode switching; the hierarchical and progressive control strategy avoids the on-off operation, that is, after detecting the overcharging risk, the first level response is performed to reduce the output power, and if the risk still exists, that is, the minimum operation power is still higher than the battery receiving capacity, the second level response is performed, that is, the self-consumption mode is entered, so that a multi-level and gradual continuous control process is realized. Secondly, the introduction of the self-consumption mode realizes the equivalent protection effect without shutdown. For the fuel cell system itself, the self-consumption mode and the shutdown state are completely different, the former maintains the relative stability of the temperature, humidity and chemical reaction environment of the stack, and avoids the cooling, purging and large working condition impact after restarting. The core component attenuation caused by frequent start-stop is avoided; that is, through the hierarchical power control and the self-consumption mode, the control logic of the overcharge prevention is upgraded from the on-off operation to the continuous adjustment type fine management, which ensures the safety of the power battery and protects the durability of the fuel cell system itself. The technical problem of frequent start-stop of the system caused by the strategy of directly shutting down the fuel cell to prevent overcharging and further shortening the service life of the fuel cell is solved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0018] Figure 1 A flowchart of a fuel cell vehicle power battery overcharge prevention method provided by the embodiments of the present application is shown. Figure 2 A flowchart of a power battery overcharge prevention module provided by the embodiments of the present application is shown. DETAILED DESCRIPTION

[0019] In order to make the technical personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of the present application.

[0020] In order to make the technical problems to be solved by the present application more clear, the reasons for the technical problems will be analyzed in detail.

[0021] The existing technology directly closes the fuel cell system to prevent overcharge, which is a passive response to its inherent contradictions, rather than a fundamental solution. The generation of this technical problem mainly shows that: From the system level, the inherent contradiction between the minimum operating power of the fuel cell system and the real-time charging acceptance ability of the power battery; this is the root cause of the overcharge risk. The fuel cell system, especially the high-power system, has an insurmountable minimum stable operating power to maintain its stable operation. However, the charging acceptance ability of the power battery, i.e. the maximum charging power currently allowed, is a dynamic variable that fluctuates dramatically with temperature, state of charge, state of health and other factors. In low temperature or high SOC conditions, the maximum charging power currently allowed may be reduced to a very low level, even to zero or negative. This forms an irreconcilable structural contradiction. When the maximum charging power currently allowed is less than the minimum stable operating power, even if the fuel cell operates at the minimum power, its output exceeds the safety boundary of the power battery, and the overcharge risk is inevitable; The contradiction between the simple and crude existing overcharge prevention scheme and the system long life operation requirement, the existing technology adopts the scheme of directly shutting down the fuel cell system, this strategy has two disadvantages, it only forcibly cuts off the charging source, and does not solve the inherent contradiction of power imbalance. Once the system is shut down, when the vehicle needs power or the battery state is slightly improved, the system must be restarted immediately, laying the foundation for the next overcharge risk, forming a vicious cycle; and the frequent start-stop and the necessary purging process after each shutdown will cause serious damage to the fuel cell stack itself. The drastic changes in humidity, temperature and potential brought by the start-stop process will accelerate the catalyst decay, proton exchange membrane aging, etc., which is contrary to the original intention of prolonging the life by setting the minimum power. Using a method that damages the system life to solve a safety problem causes a new and more hidden reliability problem.

[0022] The problem between the complex and variable whole vehicle working conditions and the simple control logic, the whole vehicle running conditions, such as city idling, high-speed cruising and frequent start-stop, are complex and variable, resulting in real-time changes of the whole vehicle demand power and the power battery state. Handing over such a continuous and dynamic power balance problem to the on-off control logic will inevitably cause the system to oscillate near the critical point and act frequently. This control logic cannot adapt to the continuous dynamic characteristics of the system, which is the direct cause of the frequent start-stop phenomenon.

[0023] In summary, the technical problem to be solved by the present application is the inherent technical contradiction of the fuel cell vehicle hybrid power system, and the direct shutdown scheme adopted by the existing technology not only fails to fundamentally resolve the contradiction, but also introduces a new contradiction that affects the core life of the system due to its own limitations. Therefore, there is an urgent need for an intelligent control method that can fundamentally coordinate this contradiction and achieve safety and life.

[0024] In a first aspect, the embodiments of the present application provide a power battery overcharge prevention method for a fuel cell vehicle, referring to Figure 1 , Figure 1 The power battery overcharge prevention method for a fuel cell vehicle provided by the embodiments of the present application is shown in the flowchart. As Figure 1 shown, a power battery overcharge prevention method for a fuel cell vehicle includes: S100, judging whether the power battery has overcharge risk based on the real-time state of the whole vehicle working condition and the power battery; if there is overcharge risk, controlling the fuel cell system to reduce the output power; S200, if the net output power is still higher than the current allowed maximum charging power of the power battery after the output power is reduced to the minimum stable running power, controlling the fuel cell system to enter the self-consumption mode, guiding the electric energy generated by the fuel cell system to the internal auxiliary machine for auxiliary consumption, and maintaining the net output power not greater than the current allowed maximum charging power.

[0025] By setting such a method, the rough power switch is replaced by fine power adjustment and mode switching; the hierarchical progressive control strategy avoids the all-or-nothing shutdown operation, that is, after detecting the overcharge risk, a first-level response is performed to reduce the output power, and if the risk still exists, that is, the minimum operating power is still higher than the battery acceptance capability, a second-level response is performed, that is, the self-consumption mode is entered, so that a multi-level and gradual continuous control process is realized. Secondly, the introduction of the self-consumption mode realizes the equivalent protection effect without shutdown. For the fuel cell system itself, the self-consumption mode and the shutdown state are completely different, the former keeps the relative stability of the temperature, humidity and chemical reaction environment of the stack, avoids the cooling, purging after shutdown and the large working condition impact during the next start, and avoids the core component attenuation caused by frequent start-stop. That is, through hierarchical power control and self-consumption mode, the overcharge prevention control logic is upgraded from on-off operation to continuous adjustment type fine management, which ensures the safety of the power battery and protects the durability of the fuel cell system itself. The technical problem of shortening the service life of the fuel cell caused by the strategy of directly shutting down the fuel cell to prevent overcharge in the prior art is solved.

[0026] In some preferred embodiments, whether the power battery has an overcharge risk is judged based on the real-time state of the power battery and the working condition of the whole vehicle, which includes the following steps: The battery management system calculates and sends the current maximum allowable charging power to the vehicle controller based on the temperature, state of charge and state of health of the power battery; The vehicle controller obtains the current net output power of the fuel cell system and the demand power of the whole vehicle; If the difference between the output power of the fuel cell system and the demand power of the whole vehicle is greater than the current maximum allowable charging power, and the duration exceeds the first preset time threshold, it is determined that there is an overcharge risk.

[0027] In this embodiment, by introducing the current maximum allowable charging power calculated by the BMS based on multiple states of the battery, that is, the temperature, SOC and SOH, the judgment basis itself is an accurate and safe dynamic value. The VCU calculates the chargeable power by comprehensively considering the net output power of the fuel cell and the demand power of the whole vehicle, that is, the difference between the two, which is real and accurate, ensuring that the root cause of the risk judgment is correct; the condition that the duration exceeds the first preset time threshold effectively filters the short-term power fluctuation caused by transient conditions such as acceleration and deceleration, avoiding frequent false triggering of the system. Only the persistent power imbalance is determined as a real risk, which improves the reliability of the control and the smoothness of the whole vehicle. The judgment logic can identify the risk trend in advance before the overcharge actually occurs.

[0028] In some preferred embodiments, the method for controlling the fuel cell system to reduce output power comprises the following steps: When the output power of the fuel cell system is reduced to the minimum stable operation power, it is determined whether the current maximum allowable charging power is less than the minimum stable operation power; if so, the output power of the fuel cell system is continuously reduced until the output power of the fuel cell system is less than the current maximum allowable charging power.

[0029] In this embodiment, it is clear that the power reduction process is not blindly followed to the end, but at the critical node of reducing to the minimum stable operation power, a judgment needs to be made. The comparison between the current maximum allowable charging power and the minimum stable operation power is the watershed of whether the whole method can solve the contradiction. It identifies the working conditions that cannot be solved by the conventional power reduction; when the result of the judgment is that the current maximum allowable charging power is less than the minimum stable operation power, the output power is continuously reduced. Here, the continuous reduction does not mean breaking through the physical lower limit of the minimum stable operation power, but through the subsequent self-consumption mode, the equivalent continuous reduction is realized at the power level.

[0030] In some preferred embodiments, the fuel cell system is controlled to reduce the output power at a preset power gradient value; wherein the preset power gradient value is adjusted according to the difference between the current maximum allowable charging power and the current net output power, and the greater the difference, the greater the preset power gradient value.

[0031] In this embodiment, by introducing a dynamically variable load reduction gradient, the optimization control of the power reduction process is realized; the greater the difference, the greater the gradient, which means that when the risk is serious, i.e. the power difference is large, the system can quickly respond and rapidly reduce the power to approach the safety zone, giving priority to safety; when the risk is small, i.e. the power difference is small, the system adopts a more gentle rate of decline to avoid unnecessary impact on the fuel cell system, which is conducive to prolonging the service life of the system. This realizes the best balance between safety and durability; the power reduction process becomes an intelligent adaptive process. The system can automatically adjust the intensity according to the emergency degree of the risk, rather than using a one-size-fits-all strategy. This control method is more in line with actual engineering needs and improves the intelligent level of the whole system control.

[0032] In some preferred embodiments, the electric energy generated by the fuel cell system is guided to the internal auxiliary machines for auxiliary consumption, which comprises the following steps: Based on the pressure of the stack and the flow demand, the speed of the air compressor is closed-loop controlled, so that the power consumption of the air compressor is increased and the net output power of the fuel cell system is reduced.

[0033] In this embodiment, by specifying the air compressor as the core energy-consuming component and adopting a closed-loop control strategy, the problem of insufficient self-consumption is solved. The air compressor is one of the auxiliary machines with the largest power consumption in the fuel cell system, and its power consumption has a large enough adjustment range to effectively absorb the power generation of the fuel cell, so that the self-consumption concept can be realized. Based on the pressure of the stack and the flow demand, the closed-loop control of the air compressor speed is the key, that is, increasing the power consumption is not at the expense of the safety of the stack operation. Through closed-loop control, while increasing the speed of the air compressor and thus increasing the power consumption, the air pressure and flow required by the stack are maintained within the safe range through the adjustment of the bleed valve and other methods. This realizes the unity of energy consumption and stability allowance. The closed-loop control can adjust the speed of the air compressor in real time and accurately according to the deviation between the target value and the actual value, thereby realizing precise control of the net output power and avoiding over-regulation or under-regulation, and ensuring the effectiveness and stability of the overcharge prevention effect.

[0034] In some preferred embodiments, the auxiliary energy consumption further comprises the following steps: On the basis of active energy consumption of the air compressor, the PTC heater in the high-pressure cooling loop is started cooperatively, and the cooling fan is adjusted to run at the highest gear.

[0035] In this embodiment, through the strategy of multi-auxiliary machine cooperative energy consumption, the robustness of the system is greatly enhanced; the PTC heater is a pure electric energy consumption device with large and controllable power consumption. The cooling fan can also contribute considerable power consumption. Starting them is equivalent to adding multiple "electric furnace filaments", which ensures that the system has enough ability to reduce the net output power to zero or even negative, and can cope with the most extreme battery failure conditions. The multi-path energy consumption constitutes a redundant system. Even if the energy consumption capacity of a certain auxiliary machine (such as the air compressor) is limited, other auxiliary machines can make up for it, ensuring the safety of the self-consumption target and greatly enhancing the reliability of the entire overcharge prevention scheme. Starting the PTC helps to heat the battery pack in a low-temperature environment, indirectly improving the battery's charging acceptance ability; increasing the fan gear enhances heat dissipation, which may be beneficial to the system thermal management. These bring additional beneficial effects.

[0036] In some preferred embodiments, to ensure the safety of the fuel cell, the following steps are further included before entering the self-consumption mode: The fuel cell controller confirms that the operating parameters of the fuel cell are in the stable interval, and sends a mode switching ready signal to the vehicle controller; After receiving the confirmation instruction, the vehicle controller performs the switching operation of the self-consumption mode.

[0037] In this embodiment, the smooth and safe mode switching is ensured by introducing a security handshake protocol; confirming that the operating parameters are in the stable interval is the primary safety barrier, which avoids high-risk mode switching when the system is in an unstable state. The two-way confirmation mechanism of sending a ready signal and receiving an acknowledgement instruction ensures that the vehicle controller and the fuel cell controller reach an agreement at the two most critical control nodes, preventing dangerous operation caused by communication errors or unilateral misjudgment, and avoiding control conflicts.

[0038] In some preferred embodiments, exit and recovery steps are also included, which comprise the following steps: When the current allowed maximum charging power is restored to be higher than the minimum stable operating power and lasts for a second preset time threshold, the vehicle controller sends an exit self-consumption mode instruction to the fuel cell controller; The fuel cell controller controls the fuel cell system to increase the net output power at a preset recovery gradient and simultaneously reduce the auxiliary additional power consumption until the system recovers to the normal power response state; During the recovery process, the vehicle controller continuously monitors whether the power battery is at risk of overcharging.

[0039] In this embodiment, the problem of how to safely and smoothly exit the overcharge prevention control and how to avoid secondary risks during the exit process is solved. If the self-consumption mode is simply exited, the overcharging risk may be immediately reintroduced or the system may be impacted; the condition of lasting for a second preset time threshold ensures that the recovery of the power battery state is stable and non-transient, effectively preventing frequent mode oscillation of the system near the critical point; increasing the net output power at a preset recovery gradient and simultaneously reducing the auxiliary additional power consumption is the core, and the increase of power and the reduction of internal energy consumption are a coordinated and gradual process rather than a jump. The smoothness of the vehicle power output is ensured, the impact on the power battery and the power battery is avoided, seamless recovery to the normal state is achieved, and the driving experience and system life are improved. During the recovery process, the vehicle controller continuously monitors whether the power battery is at risk of overcharging, ensuring that the entire control is a dynamic closed loop. Even if an exception occurs during the recovery process, the system can intervene again to form a safe closed loop management.

[0040] It should be noted that in combination with the above scheme, reference can be made to Figure 2 which is a power battery overcharge prevention module flowchart provided by the embodiments of the present application; wherein: P1 is the current allowed maximum charging power; P2 is the fuel cell system output power; P3 is the minimum stable operating power of the fuel cell system.

[0041] D1 represents that the fuel cell system immediately starts to reduce load; D2 represents that the fuel cell system continues to reduce load until the fuel cell system output power is less than the current allowed maximum charging power; D3 represents: the fuel cell system continues to be unloaded and enters the idle zero power control mode until the net output power of the fuel cell system is 0; D4 represents: after the fuel cell system is unloaded to the idle state, the fuel cell system enters the idle zero power control mode and the output power of the fuel cell system is 0; D5 represents: the PTC is turned on and the fan gear is increased; D6 represents: the system enters the air compressor energy consumption mode; D7 represents: there is no overcharge risk of the power battery, and the fuel cell system restores normal response.

[0042] In a second aspect, the application provides a power battery overcharge prevention system of a fuel cell vehicle, which comprises: a monitoring and judging module, which is used to judge whether the power battery has an overcharge risk based on the real-time state of the power battery and the working condition of the vehicle; if the power battery has an overcharge risk, the fuel cell system is controlled to reduce the output power; a control module, which is used to control the fuel cell system to enter a self-consumption mode if the net output power of the fuel cell system is still higher than the current maximum allowable charging power of the power battery after the output power is reduced to the minimum stable running power, so that the electric energy generated by the fuel cell system is guided to the internal auxiliary machines of the fuel cell system for auxiliary consumption, and the net output power of the fuel cell system is maintained to be not greater than the current maximum allowable charging power.

[0043] By setting the system, the modular design clearly defines the responsibility division of each functional unit, improves the maintainability and expandability of the system, the description of the hardware implementation provides direct technical guidance for productization, ensures the practical value of the patent protection, the corresponding relationship between the functional modules and the method steps establishes a complete protection system of the method-system, the clear interface definition ensures the collaborative work efficiency between the modules, and the overall response speed and reliability of the system are improved. All possible hardware and software architectures for implementing the power battery overcharge prevention method of the fuel cell vehicle are covered.

[0044] In a third aspect, the embodiments of the application provide a vehicle comprising the power battery overcharge prevention system of the fuel cell vehicle.

[0045] The beneficial effects brought by the application include: Provided are a fuel cell vehicle power battery overcharge prevention method, system and vehicle, wherein a rough power switch is replaced by fine power regulation and mode switching; a hierarchical progressive control strategy avoids on-off shutdown operation, that is, after detecting an overcharge risk, a first level response is performed to reduce output power, and if the risk still exists, that is, the minimum operating power is still higher than the battery receiving capacity, a second level response is performed, that is, a self-consumption mode is entered, so that a multi-level, gradual and continuous control process is realized. Secondly, the introduction of the self-consumption mode realizes the equivalent protection effect without shutdown. For the fuel cell system itself, the self-consumption mode and the shutdown state are completely different, the former keeps the relative stability of the temperature, humidity and chemical reaction environment of the stack, avoids the cooling, purging and large working condition impact after restarting, avoids the core component attenuation caused by frequent start-stop; that is, through hierarchical power control and self-consumption mode, the control logic of overcharge prevention is upgraded from on-off operation to continuous regulation and fine management, which ensures the safety of the power battery and protects the durability of the fuel cell system. The technical problem of shortening the service life of the fuel cell caused by the strategy of directly shutting down the fuel cell to prevent overcharge in the prior art is solved. The problem of battery damage caused by the decrease of the maximum allowable power of the fuel cell due to the influence of low temperature environment or the energy recovery caused by braking during driving is solved. Compared with the traditional method of directly requesting fuel to shut down, the present application can perform different solutions through multiple judgments, thereby reducing the number of fuel system shutdowns, improving the service life of the fuel system and power economy.

[0046] It should be noted that the above sequence numbers of the embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0047] The terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally further include steps or units not listed, or can optionally further include other steps or units inherent to the process, method, product or device. The terms "first", "second" and "third" and the like descriptions are used to distinguish different objects, and do not represent the order or limit the types of "first", "second" and "third".

[0048] In the description of the embodiments of the present application, "exemplary", "for example", "e.g." or "for instance" are used on the basis that a person of ordinary skill in the art will be able to bring to mind many examples of a given implementation as the implementation described in the embodiments of the present application is exemplary. Any embodiment or design scheme described as "exemplary", "for example" or "for instance" in the embodiments of the present application should not be interpreted as being more preferred than other embodiments or design schemes. Rather, the use of "exemplary", "for example", "e.g." or "for instance" is intended to present concepts in a particular manner.

[0049] In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0050] In some of the processes described in the embodiments of the present application, a plurality of operations or steps are included in a specific order, but it should be understood that these operations or steps can be executed or performed in parallel or in an order different from that in which they appear in the embodiments of the present application. The serial number of the operation is only used to distinguish different operations, and the serial number itself does not represent any execution order. In addition, these processes can include more or fewer operations, and these operations or steps can be executed in sequence or in parallel, and these operations or steps can be combined.

[0051] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment method can be realized by means of software and necessary general hardware platform, of course, it can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a plurality of instructions for making a terminal device execute the method described in each embodiment of the present application.

[0052] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method of preventing overcharging of a power cell of a fuel cell vehicle, characterized by, It comprises: Based on the whole vehicle working condition and the real-time state of the power battery, it is judged whether the power battery has overcharge risk; if there is overcharge risk, the output power of the fuel cell system is controlled to be reduced; If the net output power of the fuel cell system is still higher than the current maximum allowable charging power of the power battery after the output power is reduced to the minimum stable operation power, the fuel cell system is controlled to enter the self-consumption mode, the electric energy generated by the fuel cell system is guided to the internal auxiliary machine for auxiliary consumption, and the net output power of the fuel cell system is maintained to be not greater than the current maximum allowable charging power.

2. The overcharge prevention method for the power storage device of a fuel cell vehicle according to claim 1, characterized by, Based on the whole vehicle working condition and the real-time state of the power battery, it is judged whether the power battery has overcharge risk, which comprises the following steps: The battery management system calculates and sends the current maximum allowable charging power to the vehicle controller based on the temperature, state of charge and health state of the power battery; The vehicle controller obtains the current net output power of the fuel cell system and the whole vehicle demand power; If the difference between the output power of the fuel cell system and the whole vehicle demand power is greater than the current maximum allowable charging power, and the duration exceeds the first preset time threshold, it is determined that there is overcharge risk.

3. The method of claim 1, wherein the method is characterized by: The output power of the fuel cell system is controlled to be reduced, which comprises the following steps: When the output power of the fuel cell system is reduced to the minimum stable operation power, it is judged whether the current maximum allowable charging power is less than the minimum stable operation power; if it is less, the output power of the fuel cell system is continuously reduced until the output power of the fuel cell system is less than the current maximum allowable charging power.

4. The power battery overcharge prevention method of the fuel cell vehicle according to claim 3, characterized in that: The output power of the fuel cell system is controlled to be reduced at a preset power gradient value; wherein the preset power gradient value is adjusted according to the difference between the current maximum allowable charging power and the current net output power, and the greater the difference is, the greater the preset power gradient value is.

5. The method of claim 1, wherein the method is applied to a fuel cell vehicle power battery. The electric energy generated by the fuel cell system is guided to the internal auxiliary machine for auxiliary consumption, which comprises the following steps: Based on the stack pressure and the flow demand, the speed of the air compressor is closed-loop controlled to increase the power consumption of the air compressor and reduce the net output power of the fuel cell system.

6. The method of claim 5, wherein the voltage of the fuel cell vehicle power battery is maintained at a voltage of 3.5 V or less. The auxiliary energy consumption further comprises the following steps: On the basis of the active energy consumption of the air compressor, the PTC heater in the high-pressure cooling loop is started cooperatively, and the cooling fan is adjusted to run at the highest gear.

7. The method of claim 1, wherein the method is applied to a fuel cell vehicle power battery. To ensure the safety of the fuel cell, the following steps are further included before entering the self-consumption mode: The fuel cell controller confirms that the operating parameters of the fuel cell are in the stable interval, and sends a mode switching ready signal to the vehicle controller; After receiving the confirmation instruction, the vehicle controller performs the switching operation of the self-consumption mode.

8. The method of claim 1, wherein the method is applied to a fuel cell vehicle power battery. The method further comprises the exit and recovery steps, which comprise the following steps: When the current maximum allowable charging power recovers to be higher than the minimum stable operation power and lasts for a second preset time threshold, the vehicle controller sends an exit self-consumption mode instruction to the fuel cell controller; The fuel cell controller controls the fuel cell system to increase the net output power at a preset recovery gradient and simultaneously reduce the additional power consumption of auxiliary machines until the system returns to the normal power response state. During the recovery process, the vehicle controller continuously monitors whether the power battery is at risk of overcharging.

9. A power battery overcharge prevention system for a fuel cell vehicle, characterized by The method comprises the following steps: The monitoring and judging module is used to judge whether the power battery is at risk of overcharging based on the real-time state of the power battery and the working condition of the whole vehicle; if the power battery is at risk of overcharging, the fuel cell system is controlled to reduce the output power; The control module is used to control the fuel cell system to enter the self-consumption mode if the net output power is still higher than the current maximum charging power of the power battery after the output power is reduced to the minimum stable operation power, so as to guide the electric energy generated by the fuel cell system to the internal auxiliary machines for auxiliary consumption and maintain the net output power of the fuel cell system not greater than the current maximum charging power.

10. A vehicle characterized by comprising: The fuel cell vehicle power battery overcharge prevention system comprises the fuel cell vehicle as claimed in claim 9.

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