Fuel cell system and low idle speed control method thereof

Abstract

The invention provides a fuel cell system and a low idle speed control method thereof, and belongs to the technical field of fuel cells. The fuel cell system comprises an electric pile and accessory equipment, the accessory equipment comprises an air compressor, an intercooler, a humidifier, an expansion machine and a regulating valve, and the regulating valve comprises a bypass valve and a pile entering stop valve; filtered air enters the cathode input end of the electric pile through the air compressor, the intercooler, the humidifier and the pile entering stop valve in sequence, the first output end of the intercooler is connected with the input end of the expansion machine through the bypass valve, and the expansion machine and a motor of the air compressor coaxially rotate. The low idle speed control method comprises the following steps: controlling accessory equipment to operate in a lowest power consumption mode, and then obtaining load current of a galvanic pile and the opening degree of a regulating valve; and carrying out iterative adjustment on the load current of the electric pile and the opening degree of an adjusting valve by taking the voltage parameter value of the electric pile meeting a preset condition as a target, so as to carry out low-idle-speed control on the fuel cell system. According to the invention, low-power and high-efficiency operation of the fuel cell system can be realized, and energy loss is reduced.

Description

Technical Field

[0001] The present application relates to the field of fuel cell technology, and in particular to a fuel cell system and a low idle speed control method thereof. Background Art

[0002] Fuel cell vehicles typically feature a fuel cell and a power battery. The power battery receives energy from the fuel cell during idle operation to prevent the fuel cell's lifespan from being degraded by the vehicle's frequent starts and stops. To reduce the weight and cost of fuel cell vehicles, the power battery is relatively small, requiring the fuel cell to reduce power output during idle operation to prevent overcharging. Consequently, fuel cell system accessories are often used to dissipate idle power. However, this approach wastes excessive energy and results in inefficient fuel cell system operation. Summary of the Invention

[0003] The main purpose of this application is to propose a fuel cell system and a low idle speed control method thereof, which can achieve low-power and high-efficiency operation of the fuel cell system and reduce energy loss.

[0004] To achieve the above objectives, one aspect of the present application provides a fuel cell system, comprising a fuel cell stack and accessory equipment, wherein the accessory equipment includes an air compressor, an intercooler, a humidifier, an expander, and a regulating valve, wherein the regulating valve includes a bypass valve and a stack entry shut-off valve;

[0005] The input end of the air compressor is used to receive filtered air, the output end of the air compressor is connected to the first input end of the intercooler, the first output end of the intercooler is connected to the first input end of the humidifier, the first output end of the humidifier is connected to the cathode input end of the fuel cell stack via the stack inlet shut-off valve, the first output end of the intercooler is connected to the input end of the expander via the bypass valve, and the expander rotates coaxially with the motor of the air compressor.

[0006] To achieve the above objectives, another aspect of the present application provides a low idle speed control method, which is applied to the above fuel cell system. The method includes:

[0007] Control the accessory equipment to operate in the preset minimum power consumption mode, and then obtain the load current of the fuel cell stack and the opening of the regulating valve;

[0008] Iteratively adjusting the load current of the stack and the opening of the regulating valve with the goal of ensuring that the voltage parameter value of the stack meets a preset condition;

[0009] The fuel cell system is controlled at low idle speed according to the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve.

[0010] Furthermore, the preset conditions include a first condition, a second condition, and a third condition; and the iterative adjustment of the load current of the stack and the opening of the regulating valve with the goal of the voltage parameter value of the stack meeting the preset conditions includes:

[0011] reducing the load current of the fuel cell stack until obtaining and detecting that a voltage parameter value of the fuel cell stack satisfies the first condition;

[0012] adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies the second condition;

[0013] Acquire the minimum single-chip voltage of the stack in real time and use it as the first minimum single-chip voltage;

[0014] If the first minimum monolithic voltage is not adjusted to meet the third condition within the first preset time period, then, based on the most recent adjustment of the opening of the regulating valve, choosing to return to the step of reducing the load current of the fuel cell stack until obtaining and detecting that the voltage parameter value of the fuel cell stack meets the first condition or returning to the step of adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack meets the second condition;

[0015] If the first minimum single-chip voltage is adjusted to meet the third condition within the first preset time period, the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve are determined.

[0016] Furthermore, adjusting the opening of the regulating valve includes:

[0017] If the bypass valve is not in a fully open state, increasing the opening of the bypass valve;

[0018] If the bypass valve is in a fully open state, the opening of the stack entry stop valve is reduced.

[0019] Furthermore, the step of returning to reducing the load current of the fuel cell stack until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies the first condition or returning to adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies the second condition according to the most recent adjustment of the opening of the regulating valve includes:

[0020] If the most recent adjustment was made to the opening of the stack entry shut-off valve, or if the most recent adjustment was made to the opening of the bypass valve and the bypass valve was not fully open after the adjustment, returning to the step of reducing the stack load current until obtaining and detecting that the voltage parameter value of the stack satisfies the first condition;

[0021] If the most recent adjustment was to the opening of the bypass valve and the bypass valve is in a fully open state after the adjustment, the process returns to adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies the second condition.

[0022] Furthermore, after performing low idle control on the fuel cell system according to the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve, the method further includes:

[0023] Obtaining a minimum single-chip voltage of the battery stack and using the minimum single-chip voltage as a second minimum single-chip voltage;

[0024] If the second minimum single-cell voltage does not exceed the first preset voltage threshold and the stack entry cut-off valve is not in a fully open state, increasing the opening of the stack entry cut-off valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold;

[0025] Obtaining a maximum single-chip voltage of the battery stack and using it as a first maximum single-chip voltage;

[0026] If the first maximum single-chip voltage does not exceed the second preset voltage threshold, the current opening of the stack entry cut-off valve is maintained unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage.

[0027] Furthermore, after obtaining the maximum single-chip voltage of the battery stack and using it as the first maximum single-chip voltage, the method further includes:

[0028] If the first maximum single-cell voltage exceeds the second preset voltage threshold, reducing the opening of the stack entry cut-off valve after a second preset time period until obtaining and detecting that the maximum single-cell voltage of the stack does not exceed the second preset voltage threshold;

[0029] Obtaining a minimum single-chip voltage of the battery stack and using the minimum single-chip voltage as a third minimum single-chip voltage;

[0030] If the third minimum single-cell voltage does not exceed the first preset voltage threshold, returning to the step of increasing the opening of the stack entry cut-off valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold;

[0031] If the third minimum single-chip voltage exceeds the first preset voltage threshold, the current opening of the stack entry cut-off valve is maintained unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage.

[0032] Furthermore, after obtaining the minimum single-chip voltage of the battery stack and using it as the second minimum single-chip voltage, the method further includes:

[0033] If the second minimum single-cell voltage does not exceed the first preset voltage threshold, and the stack entry cut-off valve is in a fully open state and the bypass valve is not in a fully closed state, reducing the opening of the bypass valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold;

[0034] Obtaining a maximum single-chip voltage of the stack and using it as a second maximum single-chip voltage;

[0035] If the second maximum single-chip voltage does not exceed the second preset voltage threshold, the current opening of the bypass valve is kept unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and setting it as the second minimum single-chip voltage.

[0036] Furthermore, after obtaining the maximum single-chip voltage of the battery stack and using it as the second maximum single-chip voltage, the method further includes:

[0037] If the second maximum single-cell voltage exceeds the second preset voltage threshold, increasing the opening of the bypass valve after a third preset time period until obtaining and detecting that the maximum single-cell voltage of the stack does not exceed the second preset voltage threshold;

[0038] Obtaining a minimum single-chip voltage of the fuel cell stack and using the minimum single-chip voltage as a fourth minimum single-chip voltage;

[0039] If the fourth minimum single-cell voltage does not exceed the first preset voltage threshold, returning to the step of reducing the opening of the bypass valve until obtaining and detecting that the minimum single-cell voltage of the fuel cell stack exceeds the first preset voltage threshold;

[0040] If the fourth minimum single-chip voltage exceeds the first preset voltage threshold, the current opening of the bypass valve is kept unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage.

[0041] Furthermore, after obtaining the minimum single-chip voltage of the battery stack and using it as the second minimum single-chip voltage, the method further includes:

[0042] If the second minimum single-chip voltage does not exceed the first preset voltage threshold, and the stack entry shut-off valve is in the fully open state and the bypass valve is in the fully closed state, the speed of the air compressor is increased to restore the performance of the fuel cell stack, and then after a fourth preset time period, the process returns to the step of performing low idle control on the fuel cell system based on the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve.

[0043] The present application has at least the following beneficial effects: when the motor of the air compressor rotates coaxially with the expander, by connecting the first output end of the intercooler to the input end of the expander via a bypass valve, energy is recovered by the expander to reduce energy loss in the air compressor. By first controlling the auxiliary equipment included in the fuel cell system to operate in a preset minimum power consumption mode, and then iteratively adjusting the load current of the stack and the opening of the regulating valve until the voltage parameter value of the stack meets the preset conditions, the maximum voltage of the single chip of the stack is limited to an appropriate value, preventing catalyst oxidation at high potential. At the same time, by limiting the minimum voltage value, the stack is kept at a high efficiency, thereby achieving low-power and high-efficiency operation of the fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the structure of a fuel cell system provided in an embodiment of the present application;

[0045] Figure 2 1 is a flow chart of a low idle speed control method provided in an embodiment of the present application;

[0046] Figure 3 yes Figure 2 Flow chart of step S220 in FIG.

[0047] Figure 4 This is a schematic diagram of the implementation process of the preset idle point protection strategy provided by the embodiment of the present application;

[0048] Figure 5 This is a schematic diagram of the implementation process of the first preset protection strategy provided in the embodiment of the present application;

[0049] Figure 6 This is a schematic diagram of the implementation process of the second preset protection strategy provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are merely examples of systems and methods consistent with some aspects of the embodiments of the present application as detailed in the appended claims.

[0051] It will be understood that the terms "first", "second", etc. used in this application may be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0052] As used herein, the terms "at least one", "a plurality", "each", "any", etc., include one, two or more, include two or more, each refers to each of the corresponding plurality, and any refers to any one of the plurality. As used herein, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a method comprising a series of steps is not necessarily limited to those steps explicitly listed, but may include other steps inherent to the method that are not explicitly listed, and a system comprising a series of units is not necessarily limited to those units explicitly listed, but may include other units inherent to the system that are not explicitly listed.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0054] Fuel cell vehicles typically feature a fuel cell and a power battery. The power battery receives energy from the fuel cell during idle operation to prevent the fuel cell's lifespan from being degraded by the vehicle's frequent starts and stops. To reduce the weight and cost of fuel cell vehicles, the power battery is relatively small, requiring the fuel cell to reduce power output during idle operation to prevent overcharging. Consequently, fuel cell system accessories are often used to dissipate idle power. However, this approach wastes excessive energy and results in inefficient fuel cell system operation.

[0055] In view of this, an embodiment of the present application provides a fuel cell system and a low idle control method thereof, which can achieve low-power and high-efficiency operation of the fuel cell system and reduce energy loss.

[0056] See also Figure 1 , Figure 1 This is a schematic diagram of an optional structural composition of a fuel cell system provided in an embodiment of the present application, wherein the fuel cell system includes a fuel cell stack 110 and accessory equipment.

[0057] Specifically, the accessory equipment includes an air compressor 121, an intercooler 122, a humidifier 123, an expander 124 and a regulating valve, the regulating valve includes a bypass valve 125 and a stack shut-off valve 126, the input end of the air compressor 121 is used to receive filtered air, the output end of the air compressor 121 is connected to the first input end of the intercooler 122, the first output end of the intercooler 122 is connected to the first input end of the humidifier 123, the first output end of the humidifier 123 is connected to the cathode input end of the fuel cell stack 110 via the stack shut-off valve 126, the first output end of the intercooler 122 is connected to the input end of the expander 124 via the bypass valve 125, the expander 124 rotates coaxially with the motor of the air compressor 121, and the output end of the expander 124 is connected to the atmospheric environment.

[0058] Optionally, the accessory equipment further includes a first filter 127 and a stack outlet shut-off valve 128. The input of the first filter 127 is connected to the atmosphere to receive air, and the output of the first filter 127 is connected to the input of the air compressor 121. The cathode output of the fuel cell stack 110 is connected to the second input of the humidifier 123 via the stack outlet shut-off valve 128, and the second output of the humidifier 123 is connected to the input of the expander 124. In addition, a packaging box 111 is provided outside the fuel cell stack 110. The output of the packaging box 111 is provided with a purge pipe connected to the atmosphere, and the input of the packaging box 111 is connected to the first output of the intercooler 122.

[0059] It should be noted that the air compressor 121, the intercooler 122, the humidifier 123, the expander 124, the first filter 127, the bypass valve 125, the stack inlet shut-off valve 126 and the stack outlet shut-off valve 128 can serve as part or all of the components of the air supply subsystem, which is used to provide air to the fuel cell stack 110; wherein, the first filter 127 is used to filter particulate matter in the air, the air compressor 121 is used to deliver air with appropriate pressure and flow to the fuel cell stack 110, the intercooler 122 is used to adjust the temperature of the air to an appropriate value, the humidifier 123 is used to increase the humidity of the air to reduce the contact resistance and improve the performance of the fuel cell stack 110, and the expander 124 is used to regulate the pressure on the air side, recover energy from the exhausted gas, and improve the system efficiency.

[0060] In the present application, by connecting the first output end of the intercooler to the input end of the expander via a bypass valve, when the motor of the air compressor and the expander rotate coaxially, energy is recovered by the expander to reduce the energy loss of the air compressor.

[0061] Optionally, the accessory equipment also includes a hydrogen cylinder 131, an ejector 132, a gas-water separator 133, a stop valve 134, a proportional valve 135 and a hydrogen and water discharge valve 136. The output end of the hydrogen cylinder 131 is connected to the first input end of the ejector 132 via the stop valve 134 and the proportional valve 135 in sequence, the output end of the ejector 132 is connected to the anode input end of the fuel cell stack 110, the anode output end of the fuel cell stack 110 is connected to the input end of the gas-water separator 133, the first output end of the gas-water separator 133 is connected to the second input end of the ejector 132, and the second output end of the gas-water separator 133 is connected to the atmospheric environment via the hydrogen and water discharge valve 136.

[0062] It should be noted that the hydrogen cylinder 131, the ejector 132, the gas-water separator 133, the stop valve 134, the proportional valve 135 and the hydrogen and water discharge valve 136 can serve as part or all of the components of a hydrogen supply subsystem, which is used to provide hydrogen to the fuel cell 110; wherein, the gas-water separator 133 is used to separate the circulating gas output by the fuel cell 110 into gas and liquid, the ejector 132 is used to transmit the hydrogen received at its first input end and the hydrogen received at its second input end and output by the gas-water separator 133 to the fuel cell 110 for electrochemical reaction, and the hydrogen and water discharge valve 136 is used to discharge part of the circulating gas and liquid water through a certain opening and closing cycle to increase the concentration of circulating hydrogen.

[0063] Optionally, the accessory device further includes a second filter 141, a deionizer 142, a radiator 143, a PTC heater 144, an expansion water tank 145, a water pump 146 and a three-way valve 147. The input end of the radiator 143, the input end of the PTC heater 144 and the first input end of the expansion water tank 145 are all connected to the coolant output end of the fuel cell stack 110 and the second output end of the intercooler 122. The output end of the radiator 143 and the output end of the PTC heater 144 are both connected to the three-way valve 147. It is connected to the input end of the water pump 146, the output end of the radiator 143 is connected to the second input end of the expansion water tank 145, the input end of the deionizer 142 and the input end of the water pump 146 are both connected to the output end of the expansion water tank 145, the output end of the deionizer 142 is connected to the input end of the water pump 146, the output end of the water pump 146 is connected to the input end of the second filter 141, and the coolant input end of the fuel cell stack 110 and the second input end of the intercooler 122 are both connected to the output end of the second filter 141.

[0064] It should be noted that the second filter 141, the deionizer 142, the radiator 143, the PTC heater 144, the expansion tank 145, the water pump 146 and the three-way valve 147 can serve as part or all of the components of the thermal management subsystem, which is used to dissipate heat during the operation of the fuel cell stack 110; wherein, the second filter 141 is used to filter impurities in the coolant, the deionizer 142 is used to reduce the ion concentration in the coolant to ensure system insulation, the radiator 143 is used to dissipate heat for the coolant flowing through, and the heat dissipation efficiency can be improved by arranging a fan on the radiator 143, the PTC heater 144 is used to assist in heating the coolant when the fuel cell system is cold started at low temperature, the expansion tank 145 is used to store the coolant and remove bubbles in the water channel, and the water pump 146 is used to increase the flow rate of the coolant.

[0065] It should be noted that each two devices in the fuel cell system that are connected can be connected through a pipeline, and metal pipelines, composite pipelines, flexible hoses, etc. can be selected according to the actual application scenario. This application does not limit this.

[0066] See also Figure 2 , Figure 2 This is an optional flow chart of a low idle speed control method provided in an embodiment of the present application. The method is applied to the above-mentioned fuel cell system. The method may include, but is not limited to, the following steps S210 to S230:

[0067] Step S210: Control the accessory device to operate in a preset minimum power consumption mode, and then obtain the load current of the fuel cell stack and the opening of the regulating valve;

[0068] Step S220: iteratively adjust the stack load current and the opening of the regulating valve with the goal of ensuring that the voltage parameter value of the stack meets the preset conditions;

[0069] Step S230: performing low idle control on the fuel cell system according to the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve.

[0070] In steps S210 to S230 shown in the embodiment of the present application, by first controlling the accessory equipment included in the fuel cell system to operate in a preset minimum power consumption mode, and then iteratively adjusting the load current of the fuel cell stack and the opening of the regulating valve until the voltage parameter value of the fuel cell stack meets the preset conditions, the air intake volume of the fuel cell stack can be reduced, thereby achieving long-life, low-power, and high-efficiency operation of the fuel cell system.

[0071] In step S210 of some embodiments, controlling the accessory device to operate in a preset minimum power consumption mode can be understood as controlling some or all of the sub-devices contained in the accessory device to operate at their respective preset minimum control parameter values, such as: adjusting the speed of the air compressor to the preset minimum value of 30,000 rpm, adjusting the speed of the water pump to the preset minimum value of 2,000 rpm, etc.

[0072] In step S220 of some embodiments, since the fuel cell system is actually a high-power fuel cell system with a large number of cell stacks, the voltage parameter values of the cell stack include the average single-cell voltage, the minimum single-cell voltage and the maximum single-cell voltage of the cell stack; wherein the average single-cell voltage of the cell stack refers to the average value of all voltages corresponding to all single-cell batteries contained in the cell stack, the minimum single-cell voltage of the cell stack refers to the minimum value of all voltages corresponding to all single-cell batteries contained in the cell stack, and the maximum single-cell voltage of the cell stack refers to the maximum value of all voltages corresponding to all single-cell batteries contained in the cell stack.

[0073] In step S220 of some embodiments, the preset condition is proposed based on the voltage parameter value of the fuel cell stack, and includes a first condition, a second condition, and a third condition, which are specifically described as follows:

[0074] The first condition is used to limit the average single-chip voltage of the battery stack to be greater than a first preset threshold, the maximum single-chip voltage of the battery stack to be greater than a second preset threshold, and the minimum single-chip voltage of the battery stack to be greater than a third preset threshold;

[0075] The second condition is used to limit the average single-chip voltage of the battery stack to be approximately equal to the first preset threshold, the maximum single-chip voltage of the battery stack to be less than or equal to the second preset threshold, and the minimum single-chip voltage of the battery stack to be greater than or equal to the third preset threshold; wherein a first error allowable range with a smaller fluctuation amplitude can be set for the first preset threshold, and when the average single-chip voltage of the battery stack falls within the first error allowable range, it is determined that the average single-chip voltage of the battery stack is approximately equal to the first preset threshold;

[0076] The third condition is used to limit the minimum single-chip voltage of the stack to be approximately equal to a fourth preset threshold value, where the fourth preset threshold value is the difference between the third preset threshold value and a preset adjustment amount. A second error tolerance range with a smaller fluctuation amplitude can be set for the fourth preset threshold value. When the minimum single-chip voltage of the stack falls within the second error tolerance range, it is determined that the minimum single-chip voltage of the stack is approximately equal to the fourth preset threshold value.

[0077] The first preset threshold is preferably set to 830 mV, the second preset threshold is preferably set to 845 mV, the third preset threshold is preferably set to 810 mV, and the preset adjustment amount is preferably set to 10 mV.

[0078] In the present application, by taking the maximum single-chip voltage of the fuel cell stack as the basis for judgment, it is possible to prevent catalyst oxidation at high potential of the fuel cell stack after adjusting the load current of the fuel cell stack and the opening of the regulating valve; by taking the minimum single-chip voltage of the fuel cell stack as the basis for judgment, it is possible to ensure that the fuel cell stack operates stably at a higher efficiency after adjusting the load current of the fuel cell stack and the opening of the regulating valve.

[0079] See also Figure 3 In some embodiments, step S220 may include, but is not limited to, the following steps S310 to S350:

[0080] Step S310: reducing the load current of the fuel cell stack until obtaining and detecting that a voltage parameter value of the fuel cell stack satisfies a first condition;

[0081] Step S320: adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies a second condition;

[0082] Step S330: Acquire the minimum single-chip voltage of the stack in real time and use it as the first minimum single-chip voltage to determine whether the first minimum single-chip voltage is adjusted to meet the third condition within a first preset time period, where the first preset time period can be set to 2 minutes; if not, execute step S340; if so, execute step S350;

[0083] Step S340: Based on the most recent adjustment of the opening of the regulating valve, choose to return to step S310 or step S320;

[0084] Step S350: Determine the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve.

[0085] In the present application, low-power operation of the fuel cell system can be effectively achieved by reasonably adjusting the opening of the regulating valve according to the voltage parameter value of the fuel cell stack in the constant current mode.

[0086] It is understood that the implementation of the above-mentioned step S310 is as follows: the load current of the battery stack is adjusted to decrease once according to a first preset step size to increase the voltage of the single-chip of the battery stack, and then the voltage parameter value of the battery stack is obtained and it is determined whether it meets the first condition; if it does, step S320 is executed; if it does not meet the first condition, the load current of the battery stack is adjusted to decrease once again according to the first preset step size, and then the voltage parameter value of the battery stack is obtained and determined. The first preset step size is preferably set to 2A, and the load current of the battery stack is preferably set to be adjusted to decrease from an initial baseline value of 20A.

[0087] In the above step S320, the adjustment method of the opening of the regulating valve may include the following situations:

[0088] (1) If the bypass valve is not fully open, that is, the opening of the bypass valve is less than 100%, then increase the opening of the bypass valve. In this case, there is no need to adjust the opening of the stack shut-off valve.

[0089] (2) If the bypass valve is in a fully open state, that is, the opening of the bypass valve is 100%, the opening of the stack entry shut-off valve is reduced.

[0090] Among them, the second preset step size can be used to increase the opening of the bypass valve so that the single-chip voltage of the fuel cell stack decreases due to the reduction in air volume, and the second preset step size is preferably set to 10%; the third preset step size can be used to decrease the opening of the stack shut-off valve so that the current and single-chip voltage of the fuel cell stack both decrease due to the reduction in air volume, and the third preset step size is preferably set to 10%.

[0091] It can be understood that the implementation method of the above-mentioned step S320 is: adjust the opening of the regulating valve once according to the preset step size, then obtain the voltage parameter value of the fuel cell stack and judge whether it meets the second condition; if it does, execute step S330; if it does not, continue to adjust the opening of the regulating valve once according to the preset step size and then obtain and judge the voltage parameter value of the fuel cell stack.

[0092] In the present application, by limiting the opening of the bypass valve to increase until it reaches 100% before allowing the opening of the stack shut-off valve to be reduced, and using the bypass valve to connect the expander to recover the bypass gas energy, the energy loss can be reduced while reducing the air intake volume of the fuel cell stack.

[0093] In the above step S340, the manner of selecting whether to return to step S310 or step S320 according to the most recent adjustment of the opening of the regulating valve may include the following situations:

[0094] (1) If the most recent adjustment was to the opening of the stack entry shutoff valve, then return to step S310;

[0095] (2) If the most recent adjustment is to the opening of the bypass valve and the bypass valve is not in a fully open state after the adjustment, return to step S310;

[0096] (3) If the most recent adjustment is to the opening of the bypass valve and the bypass valve is in a fully open state after the adjustment, then return to step S320.

[0097] In the present application, it is considered that the smaller the load current of the fuel cell stack, the smaller the power output of the fuel cell stack, the higher the single cell voltage of the fuel cell stack, and the catalyst inside the fuel cell stack will oxidize at a high potential, resulting in a decrease in the activity of the fuel cell stack and a reduction in the service life of the fuel cell stack. When the fuel cell stack is operated at a certain load current, if the voltage parameter value of the fuel cell stack still cannot meet the preset conditions and the bypass valve is in a fully open state, the voltage parameter value of the fuel cell stack is directly determined by adjusting the opening of the stack shut-off valve, which can avoid unreasonable adjustment of the load current of the fuel cell stack, reduce the output power of the fuel cell stack and improve the operating safety of the fuel cell stack.

[0098] In the above step S350, the method for determining the iteratively adjusted load current of the stack and the opening of the regulating valve may include the following:

[0099] The current load current of the stack, the current opening of the bypass valve, and the current opening of the stack entry shutoff valve are obtained. The current load current of the stack is used as the iteratively adjusted load current of the stack, which can be understood as the idle current, and the corresponding power is the idle power. The current opening of the bypass valve is directly used as the iteratively adjusted opening of the bypass valve, and the current opening of the stack entry shutoff valve is directly used as the iteratively adjusted opening of the stack entry shutoff valve. It should be noted that the iteratively adjusted openings of the bypass valve and the stack entry shutoff valve are generally not zero.

[0100] In some embodiments, the low idle control method may further include: enabling a preset idle point protection strategy to adaptively adjust the low idle control process of the fuel cell system.

[0101] See also Figure 4 Specifically, the specific implementation process of the preset idle point protection strategy may include, but is not limited to, the following steps S410 to S470:

[0102] Step S410: obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage;

[0103] Step S420: Determine whether the second minimum single-chip voltage exceeds a first preset voltage threshold, which is preferably set to 780 mV; if so, return to step S410; if not, execute step S430;

[0104] Step S430: Determine whether the stack entry cutoff valve is in a fully open state, that is, determine whether the opening of the stack entry cutoff valve is 100%; if so, execute step S440; if not, execute step S450;

[0105] Step S440: Determine whether the bypass valve is in a fully closed state, that is, determine whether the opening of the bypass valve is 0%; if so, execute step S460; if not, execute step S470;

[0106] Step S450: activating a first preset protection strategy to adaptively adjust the opening of the stack entry shut-off valve;

[0107] Step S460: Increase the speed of the air compressor to restore the performance of the fuel cell stack, and then return to step S230 after a fourth preset time period, which is preferably set to 10 seconds;

[0108] Step S470: Activate the second preset protection strategy to adaptively adjust the opening of the bypass valve.

[0109] In this application, considering that the reaction water may not be discharged in time after the fuel cell stack has been running at low idle for a long time, thereby clogging the active sites, resulting in insufficient battery reaction gas and degradation of single cell performance, enabling the preset idle point protection strategy during the low idle control of the fuel cell system will help restore the performance of the fuel cell stack and ensure the operational reliability of the fuel cell system.

[0110] See also Figure 5 In step S450 of some embodiments, the specific implementation process of the first preset protection strategy may include, but is not limited to, the following steps S510 to S550:

[0111] Step S510: increasing the opening of the stack entry cut-off valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold;

[0112] Step S520: Obtain the maximum single-chip voltage of the stack and use it as the first maximum single-chip voltage. Then determine whether the first maximum single-chip voltage exceeds a second preset voltage threshold, which is preferably set to 845 mV. If not, execute step S550; if exceeded, execute step S530.

[0113] Step S530: after a second preset time period, reducing the opening of the stack entry cut-off valve until obtaining and detecting that the maximum cell voltage of the stack does not exceed the second preset voltage threshold; wherein the second preset time period is preferably set to 10 seconds;

[0114] Step S540: Obtain the minimum single-chip voltage of the stack and use it as the third minimum single-chip voltage, and then determine whether the third minimum single-chip voltage exceeds the first preset voltage threshold; if not, return to step S510; if so, execute step S550;

[0115] Step S550: Keep the current opening of the stack entry cut-off valve unchanged, and then return to step S410.

[0116] In the present application, the opening of the stack shut-off valve is appropriately adjusted during the low idle control of the fuel cell system, thereby timely adjusting the air intake volume of the stack and improving the operational stability of the stack.

[0117] It can be understood that the implementation method of the above-mentioned step S510 is: the opening of the stack entry shut-off valve is increased and adjusted once according to the third preset step size, and then the minimum single-chip voltage of the fuel cell stack is obtained and it is judged whether it exceeds the first preset voltage threshold; if it exceeds, step S520 is executed; if it does not exceed, the opening of the stack entry shut-off valve is continued to be increased and adjusted once according to the third preset step size and then the minimum single-chip voltage of the fuel cell stack is obtained and judged.

[0118] It can be understood that the implementation method of the above-mentioned step S530 is: controlling the current opening of the stack entry shut-off valve to remain unchanged within the second preset time period, then randomly reducing and adjusting the opening of the stack entry shut-off valve, and then obtaining the maximum single-chip voltage of the fuel cell stack and judging whether it exceeds the second preset voltage threshold; if not, executing step S540; if exceeded, continuing to randomly reduce and adjust the opening of the stack entry shut-off valve and then obtaining and judging the maximum single-chip voltage of the fuel cell stack.

[0119] See also Figure 6 In step S470 of some embodiments, the specific implementation process of the second preset protection strategy may include, but is not limited to, the following steps S610 to S650:

[0120] Step S610: reducing the opening of the bypass valve until obtaining and detecting that the minimum single-cell voltage of the fuel cell stack exceeds the first preset voltage threshold;

[0121] Step S620: Obtain the maximum single-chip voltage of the stack and use it as the second maximum single-chip voltage, and then determine whether the second maximum single-chip voltage exceeds the second preset voltage threshold; if not, execute step S650; if exceeded, execute step S630;

[0122] Step S630: increasing the opening of the bypass valve after a third preset time period until obtaining and detecting that the maximum cell voltage of the stack does not exceed the second preset voltage threshold; wherein the third preset time period is preferably set to 10 seconds;

[0123] Step S640: Obtain the minimum single-chip voltage of the stack and use it as the fourth minimum single-chip voltage, and then determine whether the fourth minimum single-chip voltage exceeds the first preset voltage threshold; if not, return to step S610; if so, execute step S650;

[0124] Step S650: Keep the current opening of the bypass valve unchanged, and then return to step S410.

[0125] In the present application, the opening of the bypass valve is appropriately adjusted during the low idle control process of the fuel cell system, so as to timely adjust the air intake volume of the fuel cell stack and improve the operational stability of the fuel cell stack.

[0126] It can be understood that the implementation method of the above-mentioned step S610 is: the opening of the bypass valve is adjusted to be reduced once according to the second preset step size, and then the minimum single-chip voltage of the fuel cell stack is obtained and it is determined whether it exceeds the first preset voltage threshold; if it exceeds, step S620 is executed; if it does not exceed, the opening of the bypass valve is continued to be adjusted to be reduced once according to the second preset step size and then the minimum single-chip voltage of the fuel cell stack is obtained and determined.

[0127] It can be understood that the implementation method of the above-mentioned step S630 is: control the current opening of the bypass valve to remain unchanged within the third preset time period, then perform a random increase adjustment on the opening of the bypass valve, and then obtain the maximum single-chip voltage of the battery stack and judge whether it exceeds the second preset voltage threshold; if not, execute step S640; if exceeded, continue to perform a random increase adjustment on the opening of the bypass valve and then obtain and judge the maximum single-chip voltage of the battery stack.

[0128] The present application also provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the low idle control method described above when executing the computer program. The electronic device may include any intelligent terminal such as a tablet computer or an in-vehicle computer.

[0129] It can be understood that the contents of the above method embodiments are all applicable to the embodiments of the present device, the functions specifically implemented by the embodiments of the present device are the same as the functions specifically implemented by the above method embodiments, and the beneficial effects achieved by the embodiments of the present device are also the same as the beneficial effects achieved by the above method embodiments.

[0130] The embodiments described above are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0131] Those skilled in the art will appreciate that the technical solutions shown in the figures do not limit the embodiments of the present application and may include more or fewer steps than shown, or combinations of certain steps, or different steps. The system embodiments described above are merely illustrative and some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments.

[0132] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A fuel cell system, characterized in that: It includes a fuel cell stack and accessory equipment, wherein the accessory equipment includes an air compressor, an intercooler, a humidifier, an expander and a regulating valve, wherein the regulating valve includes a bypass valve and a stack entry shut-off valve; The input end of the air compressor is used to receive filtered air, the output end of the air compressor is connected to the first input end of the intercooler, the first output end of the intercooler is connected to the first input end of the humidifier, the first output end of the humidifier is connected to the cathode input end of the fuel cell stack via the stack inlet shut-off valve, the first output end of the intercooler is connected to the input end of the expander via the bypass valve, and the expander rotates coaxially with the motor of the air compressor.

2. A low idle speed control method, characterized in that: Applied to the fuel cell system of claim 1, the method comprising: Control the accessory equipment to operate in the preset minimum power consumption mode, and then obtain the load current of the fuel cell stack and the opening of the regulating valve; Iteratively adjusting the load current of the stack and the opening of the regulating valve with the goal of ensuring that the voltage parameter value of the stack meets a preset condition; The fuel cell system is controlled at low idle speed according to the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve.

3. The low idle speed control method according to claim 2, characterized in that: The preset conditions include a first condition, a second condition, and a third condition; and the iterative adjustment of the load current of the stack and the opening of the regulating valve with the goal of ensuring that the voltage parameter value of the stack meets the preset conditions includes: reducing the load current of the fuel cell stack until obtaining and detecting that a voltage parameter value of the fuel cell stack satisfies the first condition; adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies the second condition; Acquire the minimum single-chip voltage of the stack in real time and use it as the first minimum single-chip voltage; If the first minimum monolithic voltage is not adjusted to meet the third condition within the first preset time period, then, based on the most recent adjustment of the opening of the regulating valve, choosing to return to the step of reducing the load current of the fuel cell stack until obtaining and detecting that the voltage parameter value of the fuel cell stack meets the first condition or returning to the step of adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack meets the second condition; If the first minimum single-chip voltage is adjusted to meet the third condition within the first preset time period, the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve are determined.

4. The low idle speed control method according to claim 3, characterized in that: The adjusting the opening of the regulating valve includes: If the bypass valve is not in a fully open state, increasing the opening of the bypass valve; If the bypass valve is in a fully open state, the opening of the stack entry stop valve is reduced.

5. The low idle speed control method according to claim 4, characterized in that: The step of returning to reducing the load current of the fuel cell stack according to the most recent adjustment of the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack meets the first condition or returning to adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack meets the second condition includes: If the most recent adjustment was made to the opening of the stack entry shut-off valve, or if the most recent adjustment was made to the opening of the bypass valve and the bypass valve was not fully open after the adjustment, returning to the step of reducing the stack load current until obtaining and detecting that the voltage parameter value of the stack satisfies the first condition; If the most recent adjustment was to the opening of the bypass valve and the bypass valve is in a fully open state after the adjustment, the process returns to adjusting the opening of the regulating valve until obtaining and detecting that the voltage parameter value of the fuel cell stack satisfies the second condition.

6. The low idle speed control method according to any one of claims 2 to 5, characterized in that: After performing low idle control on the fuel cell system according to the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve, the method includes: Obtaining a minimum single-chip voltage of the battery stack and using the minimum single-chip voltage as a second minimum single-chip voltage; If the second minimum single-cell voltage does not exceed the first preset voltage threshold and the stack entry cut-off valve is not in a fully open state, increasing the opening of the stack entry cut-off valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold; Obtaining a maximum single-chip voltage of the battery stack and using it as a first maximum single-chip voltage; If the first maximum single-chip voltage does not exceed the second preset voltage threshold, the current opening of the stack entry cut-off valve is maintained unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage.

7. The low idle speed control method according to claim 6, characterized in that: After obtaining the maximum single-chip voltage of the battery stack and using it as the first maximum single-chip voltage, the method includes: If the first maximum single-cell voltage exceeds the second preset voltage threshold, reducing the opening of the stack entry cut-off valve after a second preset time period until obtaining and detecting that the maximum single-cell voltage of the stack does not exceed the second preset voltage threshold; Obtaining a minimum single-chip voltage of the battery stack and using the minimum single-chip voltage as a third minimum single-chip voltage; If the third minimum single-cell voltage does not exceed the first preset voltage threshold, returning to the step of increasing the opening of the stack entry cut-off valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold; If the third minimum single-chip voltage exceeds the first preset voltage threshold, the current opening of the stack entry cut-off valve is maintained unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage.

8. The low idle speed control method according to claim 6, characterized in that: After obtaining the minimum single-chip voltage of the battery stack and using it as the second minimum single-chip voltage, the method includes: If the second minimum single-cell voltage does not exceed the first preset voltage threshold, and the stack entry cut-off valve is in a fully open state and the bypass valve is not in a fully closed state, reducing the opening of the bypass valve until obtaining and detecting that the minimum single-cell voltage of the stack exceeds the first preset voltage threshold; Obtaining a maximum single-chip voltage of the stack and using it as a second maximum single-chip voltage; If the second maximum single-chip voltage does not exceed the second preset voltage threshold, the current opening of the bypass valve is kept unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and setting it as the second minimum single-chip voltage.

9. The low idle speed control method according to claim 8, characterized in that: After obtaining the maximum single-chip voltage of the battery stack and using it as the second maximum single-chip voltage, the method includes: If the second maximum single-cell voltage exceeds the second preset voltage threshold, increasing the opening of the bypass valve after a third preset time period until obtaining and detecting that the maximum single-cell voltage of the stack does not exceed the second preset voltage threshold; Obtaining a minimum single-chip voltage of the fuel cell stack and using the minimum single-chip voltage as a fourth minimum single-chip voltage; If the fourth minimum single-cell voltage does not exceed the first preset voltage threshold, returning to the step of reducing the opening of the bypass valve until obtaining and detecting that the minimum single-cell voltage of the fuel cell stack exceeds the first preset voltage threshold; If the fourth minimum single-chip voltage exceeds the first preset voltage threshold, the current opening of the bypass valve is kept unchanged, and the process returns to the step of obtaining the minimum single-chip voltage of the stack and using it as the second minimum single-chip voltage.

10. The low idle speed control method according to claim 6, characterized in that: After obtaining the minimum single-chip voltage of the battery stack and using it as the second minimum single-chip voltage, the method further includes: If the second minimum single-chip voltage does not exceed the first preset voltage threshold, and the stack entry shut-off valve is in the fully open state and the bypass valve is in the fully closed state, the speed of the air compressor is increased to restore the performance of the fuel cell stack, and then after a fourth preset time period, the process returns to the step of performing low idle control on the fuel cell system based on the iteratively adjusted load current of the fuel cell stack and the opening of the regulating valve.

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