A multi-stack series-connected controllable fuel cell system, a closed stack control method, and a vehicle
By configuring dual-switch units and solenoid valve groups for multi-stack series fuel cell systems, the connection relationship of the stacks is controlled, solving the problem of high stack potential under low power output, and achieving the effects of high power output and extended lifespan.
Patent Information
- Application Number
- CN202411922494.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2044-12-25
AI Technical Summary
In existing technologies, multi-stack series fuel cells, under low power output and idling conditions, cause individual cells inside the stack to be at high potential, affecting the stack's operating life.
By configuring each fuel cell stack with a dual-switch unit, a first solenoid valve group, a second solenoid valve group, and a third solenoid valve group, the connection between the fuel cell stack and the high-voltage power module, the air supply module, the hydrogen supply module, and the thermal management module is controlled, enabling high-power output and partial shutdown of the fuel cell stack under low-power demand, thus avoiding degradation phenomena such as carbon corrosion caused by high potential.
This achieves stable output of the fuel cell system over a high power range, extends the stack's operating life, and avoids stack damage caused by high potential.
Smart Images
Figure CN119852466B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of fuel cell technology, and in particular to a multi-stack series controllable fuel cell system, a closed-stack control method, and a vehicle. Background Technology
[0002] In existing technologies, most fuel cells use a multi-stack series configuration to achieve high power output. This is achieved by evenly distributing the vehicle's power demand to each stack and ensuring uniform distribution of the water, hydrogen, and air medium within the stack. However, vehicles also have requirements for low power output and idling during operation. If the relatively small power demand of the vehicle is evenly distributed to each stack, it would cause each cell within the stack to be at a high potential, thus affecting the stack's lifespan. Summary of the Invention
[0003] The main objective of this application is to propose a multi-stack series controllable fuel cell system, a closed-stack control method, and a vehicle to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.
[0004] To achieve the above objectives, one aspect of this application proposes a multi-stack series controllable fuel cell system, including a stack module, a high-voltage power module, a dual-switch module, an air supply module, a first solenoid valve module, a hydrogen supply module, a second solenoid valve module, a thermal management module, and a third solenoid valve module.
[0005] The fuel cell module includes multiple fuel cells connected in series. The series connection between the negative terminal of each fuel cell and the positive terminal of the next fuel cell is referred to as an electrical line. The positive terminal of the first fuel cell is connected to the positive terminal of the high-voltage power module to form an electrical line, and the negative terminal of the last fuel cell is connected to the negative terminal of the high-voltage power module.
[0006] The dual-switch module includes a dual-switch unit configured for each of the fuel cell stacks. The dual-switch unit includes a first relay switch and a second relay switch. The first relay switch is disposed on the electrical line associated with the positive terminal of the fuel cell stack. A first terminal of the first relay switch is connected to the positive terminal of the fuel cell stack. A second terminal of the first relay switch is connected to the first terminal of the second relay switch. A second terminal of the second relay switch is connected to the negative terminal of the fuel cell stack.
[0007] The first solenoid valve module includes a first solenoid valve group configured for each of the fuel cell stacks, the first solenoid valve group being used to control the air supply module to supply air to the fuel cell stacks;
[0008] The second solenoid valve module includes a second solenoid valve group configured for each of the fuel cell stacks, the second solenoid valve group being used to control the hydrogen supply module to supply hydrogen to the fuel cell stacks;
[0009] The third solenoid valve module includes a third solenoid valve group configured for each of the fuel cell stacks, the third solenoid valve group being used to control the thermal management module to supply coolant to the fuel cell stacks.
[0010] Furthermore, the first solenoid valve group configured for each of the fuel cell stacks includes a first input solenoid valve and a first output solenoid valve. The cathode inlet of the fuel cell stack is connected to the air supply module through the first input solenoid valve, and the cathode outlet of the fuel cell stack is connected to the air supply module through the first output solenoid valve.
[0011] Furthermore, the second solenoid valve group configured for each of the fuel cell stacks includes a second input solenoid valve and a second output solenoid valve. The anode inlet of the fuel cell stack is connected to the hydrogen supply module through the second input solenoid valve, and the anode outlet of the fuel cell stack is connected to the hydrogen supply module through the second output solenoid valve.
[0012] Furthermore, the third solenoid valve group configured for each of the fuel cell stacks includes a third input solenoid valve and a third output solenoid valve. The coolant inlet of the fuel cell stack is connected to the thermal management module through the third input solenoid valve, and the coolant outlet of the fuel cell stack is connected to the thermal management module through the third output solenoid valve.
[0013] To achieve the above objectives, another aspect of this application proposes a closed-cell control method applied to the aforementioned multi-stack series controllable fuel cell system, the closed-cell control method comprising:
[0014] When multiple electrically connected fuel cells are in normal operating condition, obtain the current power requirement of the entire vehicle;
[0015] Based on the current power demand of the vehicle, determine the number of fuel cells that need to be shut down.
[0016] When the number of fuel cells is greater than zero, obtain the historical operating parameter values of the multiple fuel cells;
[0017] Based on the number of fuel cells and the historical operating parameter values of the multiple fuel cells, all target fuel cells that need to be shut down are selected from the multiple fuel cells, and then the shutdown operation is performed on all target fuel cells.
[0018] Furthermore, each of the fuel cell stacks being in normal operating condition includes: a first relay switch configured for the fuel cell stack being in a closed state, a second relay switch configured for the fuel cell stack being in a closed state, a first solenoid valve group configured for the fuel cell stack being in an open state at a preset opening degree, and a second solenoid valve group and a third solenoid valve group configured for the fuel cell stack being in a fully open state.
[0019] Furthermore, controlling all target fuel cells to shut down includes:
[0020] For each target battery stack, the first relay switch configured for the target battery stack is controlled to be in the open state, and the second relay switch configured for the target battery stack is controlled to be in the closed state;
[0021] The first solenoid valve group configured for the target fuel cell stack is controlled to be fully open, and then the air supply module is controlled to purge the target fuel cell stack with air for a first preset duration.
[0022] The first solenoid valve group configured for the target fuel cell stack is controlled to be fully closed, and then the target fuel cell stack is controlled to perform oxygen-consuming discharge for a second preset duration.
[0023] The second solenoid valve group configured for the target fuel cell stack is controlled to be fully closed, and then after a third preset time period, the third solenoid valve group configured for the target fuel cell stack is controlled to be fully closed.
[0024] Further, the historical operating parameter values of the multiple fuel cell stacks include the historical operating duration of the multiple fuel cell stacks; the step of selecting all target fuel cell stacks that need to be shut down from the multiple fuel cell stacks based on the number of fuel cell stacks and the historical operating parameter values of the multiple fuel cell stacks includes:
[0025] Select all fuel cell stacks with the longest historical operating time that match the number of fuel cell stacks from the plurality of fuel cell stacks, and use the selected fuel cell stacks as the target fuel cell stacks that need to be shut down.
[0026] Further, the historical operating parameter values of the plurality of fuel cell stacks include the average individual voltage of the plurality of fuel cell stacks; the step of selecting all target fuel cell stacks that need to be shut down from the plurality of fuel cell stacks based on the number of fuel cell stacks and the historical operating parameter values of the plurality of fuel cell stacks includes:
[0027] From the plurality of fuel cell stacks, select all fuel cell stacks with the lowest average individual voltage that match the number of fuel cell stacks, and use the selected fuel cell stacks as the target fuel cell stacks that need to be shut down.
[0028] To achieve the above objectives, another aspect of this application proposes a vehicle including the aforementioned multi-stack series controllable fuel cell system.
[0029] This application includes at least the following beneficial effects: When multiple fuel cell stacks are in an electrically connected series state, by configuring a dual-switch unit for each stack to control the power output received by the stack from the high-voltage power module, by configuring a first solenoid valve group for each stack to control the connection between the stack and the air supply module, by configuring a second solenoid valve group for each stack to control the connection between the stack and the hydrogen supply module, and by configuring a third solenoid valve group for each stack to control the connection between the stack and the thermal management module, multiple fuel cell stacks can operate simultaneously to achieve high power output. Alternatively, when power demand is relatively low, some stacks can operate simultaneously to avoid carbon corrosion and other degradation phenomena caused by the fuel cell system being at a high potential. This ensures that the fuel cell system has a wide power output range and improves its operational lifespan. Furthermore, by determining the target stack to be shut down based on the historical operating parameter values of multiple stacks when power demand is relatively low and shutting it down, it is beneficial to balance the operational lifespan of multiple stacks. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the structural composition of a multi-stack series controllable fuel cell system provided in an embodiment of this application;
[0031] Figure 2 This is a schematic diagram of the structural composition of the combined fuel cell stack module, high-voltage power module, and dual-switch module provided in the embodiments of this application;
[0032] Figure 3 This is a schematic diagram of the structural composition of the combined fuel cell stack module, air supply module, and first solenoid valve module provided in the embodiments of this application;
[0033] Figure 4 This is a schematic diagram of the structural composition of the combined fuel cell stack module, the hydrogen supply module, and the second solenoid valve module provided in the embodiments of this application;
[0034] Figure 5 This is a schematic diagram of the structural composition of the combined fuel cell stack module, thermal management module, and third solenoid valve module provided in the embodiments of this application;
[0035] Figure 6 This is a schematic flowchart of a closed-loop control method provided in an embodiment of this application. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying 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 those of this application; they are merely examples of systems and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.
[0037] It is understood that the terms "first," "second," etc., used in this application may be used 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 this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information.
[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.
[0039] In existing technologies, with the gradual emergence of high-power applications in automobiles, traditional single-stack fuel cells can only achieve high power output by increasing the number of cells or the active area of the cells. However, this brings other application drawbacks, such as uneven current distribution through the cells and uneven distribution of reactants required by the cells. To overcome the application drawbacks of single-stack fuel cells, some have proposed using multi-stack series fuel cells to achieve high power output. This involves evenly distributing the vehicle's power demand to each stack and ensuring uniform distribution of the water, hydrogen, and air medium within the stack. However, since vehicles also have low power output and idling requirements during use, evenly distributing the smaller vehicle power demand to each stack would cause each cell within the stack to be at a high potential, thus affecting the stack's lifespan.
[0040] In view of this, embodiments of this application provide a multi-stack series controllable fuel cell system, a stack shut-down control method, and a vehicle. When multiple stacks are electrically connected in series, by configuring a dual-switch unit for each stack to control the power output received from the high-voltage power module, by configuring a first solenoid valve group for each stack to control the connection between the stack and the air supply module, by configuring a second solenoid valve group for each stack to control the connection between the stack and the hydrogen supply module, and by configuring a third solenoid valve group for each stack to control the connection between the stack and the thermal management module, multiple stacks can operate simultaneously to achieve high power output. Alternatively, when power demand is relatively low, some stacks can operate simultaneously to avoid the fuel cell system being at a high potential and causing degradation phenomena such as carbon corrosion. This ensures that the fuel cell system has a wide power output range and improves its operational lifespan. By determining the target stack to be shut down based on the historical operating parameter values of multiple stacks when power demand is relatively low and shutting it down, it is beneficial to balance the operational lifespan of multiple stacks.
[0041] Figure 1 This is a schematic diagram of the structure of a multi-stack series controllable fuel cell system provided in an embodiment of this application. The system mainly includes a stack module, a high-voltage power module, an air supply module, a hydrogen supply module, a thermal management module, a dual-switch module, a first solenoid valve module, a second solenoid valve module, and a third solenoid valve module. The high-voltage power module is connected to the stack module through the dual-switch module, the air supply module is connected to the stack module through the first solenoid valve module, the hydrogen supply module is connected to the stack module through the second solenoid valve module, and the thermal management module is connected to the stack module through the third solenoid valve module.
[0042] Specifically, see Figure 2 As shown, the fuel cell module includes multiple fuel cells (i.e., fuel cells 101_1 to fuel cells 101_N) connected in series. The positive terminal of the first fuel cell (i.e., fuel cell 101_1) is connected to the positive terminal of the high-voltage power module to form an electrical circuit. The negative terminal of the last fuel cell (i.e., fuel cell 101_N) is connected to the negative terminal of the high-voltage power module. The series circuit formed between the negative terminal of each fuel cell and the positive terminal of the next fuel cell is denoted as an electrical circuit. For example, the series circuit formed between the negative terminal of fuel cell 101_1 and the positive terminal of fuel cell 101_2 is denoted as an electrical circuit, the series circuit formed between the negative terminal of fuel cell 101_2 and the positive terminal of fuel cell 101_3 is denoted as an electrical circuit, and so on.
[0043] It should be noted that N represents the number of fuel cell stacks. Figure 2This diagram is only intended to better illustrate the electrical series relationship between multiple fuel cell stacks and the connection relationship between the fuel cell stack module, the high-voltage power module, and the dual-switch module. In this application, N=4 is not limited, and the specific setting is determined according to the actual application scenario of the multi-stack series controllable fuel cell system.
[0044] Specifically, see Figure 2 As shown, the dual-switch module includes a dual-switch unit configured for each fuel cell stack 101_i, i = 1, 2, ..., N. Each dual-switch unit includes a first relay switch S1_i and a second relay switch S2_i. The first relay switch S1_i is located on an electrical line associated with the positive terminal of the fuel cell stack 101_i. The first terminal of the first relay switch S1_i is connected to the positive terminal of the fuel cell stack 101_i, the second terminal of the first relay switch S1_i is connected to the first terminal of the second relay switch S2_i, and the second terminal of the second relay switch S2_i is connected to the negative terminal of the fuel cell stack 101_i. The first relay switch S1_i and the second relay switch S2_i can be used in conjunction to control the power output received by the fuel cell stack 101_i from the high-voltage power module.
[0045] In some embodiments, the high-voltage power module includes a DC-DC converter for a first battery stack (i.e., battery stack 101_1) and a first relay switch S1_1 and a second relay switch S2_1 configured therefor. The positive terminal of the DC-DC converter is connected to the positive terminal of battery stack 101_1 via the first relay switch S1_1. The positive terminal of the DC-DC converter can also be connected to the next battery stack via the second relay switch S2_1. The negative terminal of the DC-DC converter is connected to the last battery stack (i.e., battery stack 101_N). The DC-DC converter is connected to an external vehicle voltage platform and is used to convert the DC power provided by the vehicle voltage platform and supply it to battery stack 101_1 when the first relay switch S1_1 is closed and the second relay switch S2_1 is open, or to convert the DC power provided by the vehicle voltage platform and supply it to the next battery stack when the first relay switch S1_1 is open and the second relay switch S2_1 is closed.
[0046] It should be noted that this application sets multiple fuel cell stacks to operate in an electrically connected series mode, provided that the specifications and performance of each fuel cell stack 101_i are identical, and the N×M×U0 value is determined. B This expression holds true, where N is the number of multiple fuel cells, M is the total number of cells contained within a fuel cell, U0 is the maximum instantaneous output voltage of a single fuel cell cell, which is typically approximately 1V, and U... B This is the reference voltage level of the vehicle's voltage platform. For example, the reference voltage level of the vehicle's voltage platform in a common commercial vehicle design is 600V.
[0047] Furthermore, the following explanation is provided regarding the selection of this DC-DC converter: When M B When the expression / U0 is true, meaning the fuel cell stack is designed according to basic requirements, the DC-DC converter is determined to be a boost-type DC-DC converter; when M≥U B When the expression / U0 is true, it means that the fuel cell stack is designed according to special requirements, and the DC-DC converter is determined to be a buck-boost type DC-DC converter. When the operating voltage of the fuel cell stack is low, the DC-DC converter operates in boost mode, and when the operating voltage of the fuel cell stack exceeds the reference voltage level of the vehicle voltage platform, the DC-DC converter operates in buck mode.
[0048] Specifically, the first solenoid valve module includes a first solenoid valve group configured for each fuel cell stack 101_i, the first solenoid valve group being used to control the air supply module to supply air to the fuel cell stack 101_i.
[0049] In some embodiments, see Figure 3 As shown, the first solenoid valve group configured for each fuel cell stack 101_i includes a first input solenoid valve 111_i and a first output solenoid valve 112_i. The cathode inlet of the fuel cell stack 101_i is connected to the air supply module through the first input solenoid valve 111_i, and the cathode outlet of the fuel cell stack 101_i is connected to the air supply module through the first output solenoid valve 112_i. By setting the first input solenoid valve 111_i at the cathode inlet of the fuel cell stack 101_i and the first output solenoid valve 112_i at the cathode outlet of the fuel cell stack 101_i, it is beneficial to more effectively cut off and control the air supply process of the fuel cell stack 101_i, ensuring that no air enters when the fuel cell stack 101_i is shut down, thereby preventing oxidation and deactivation of the catalyst inside the fuel cell stack 101_i.
[0050] In some embodiments, see Figure 3 As shown, the air supply module includes an air compressor 121, a humidifier 122, and an expander 123. For each fuel cell stack 101_i, a first input solenoid valve 111_i and a first output solenoid valve 112_i are configured. The inlet of the air compressor 121 is connected to the atmospheric environment, and the outlet of the air compressor 121 is connected to the first inlet of the humidifier 122. The first outlet of the humidifier 122 is connected to the cathode inlet of the fuel cell stack 101_i through the first input solenoid valve 111_i. This allows air from the atmospheric environment to be processed sequentially by the air compressor 121 and the humidifier 122, and then delivered to the fuel cell stack 101_i through the first input solenoid valve 111_i. Electrochemical reactions are carried out in the fuel cell stack 101_i; the cathode outlet of the fuel cell stack 101_i is connected to the second inlet of the humidifier 122 through the first output solenoid valve 112_i, the second outlet of the humidifier 122 is connected to the inlet of the expander 123, the outlet of the expander 123 is connected to the atmospheric environment, and the expander 123 rotates coaxially with the motor of the air compressor 121, so that the humidifier 122 can mix and exchange the excess air discharged from the fuel cell stack 101_i with the air delivered by the air compressor 121. Subsequently, the expander 123 can recover energy from the gas discharged from the humidifier 122 and use it to reduce the power consumption of the air compressor 121.
[0051] Specifically, the second solenoid valve module includes a second solenoid valve group configured for each fuel cell stack 101_i, which is used to control the hydrogen supply module to supply hydrogen to the fuel cell stack 101_i.
[0052] In some embodiments, see Figure 4 As shown, the second solenoid valve group configured for each fuel cell stack 101_i includes a second input solenoid valve 131_i and a second output solenoid valve 132_i. The anode inlet of the fuel cell stack 101_i is connected to the hydrogen supply module through the second input solenoid valve 131_i, and the anode outlet of the fuel cell stack 101_i is connected to the hydrogen supply module through the second output solenoid valve 132_i. By setting the second input solenoid valve 131_i at the anode inlet and the second input solenoid valve 131_i at the anode outlet of the fuel cell stack 101_i, it is beneficial to more effectively cut off and control the hydrogen supply process of the fuel cell stack 101_i, ensuring that no hydrogen, nitrogen, or moisture enters when the fuel cell stack 101_i is shut down.
[0053] In some embodiments, see Figure 4As shown, the hydrogen supply module includes a hydrogen injection valve 141, a hydrogen inlet pressure regulating chamber 142, a gas-liquid separator 143, a hydrogen discharge and drainage valve 144, and an injector 145_i and an ejector 146_i configured for each fuel cell stack 101_i. A second input solenoid valve 131_i and a second output solenoid valve 132_i are configured for each fuel cell stack 101_i. An external hydrogen supply device is connected to the inlet of the hydrogen inlet pressure regulating chamber 142 via the hydrogen injection valve 141. The outlet of the hydrogen inlet pressure regulating chamber 142 is connected to the inlet of the injector 145_i. The outlet of the injector 145_i is connected to the first inlet of the ejector 146_i. The outlet of the ejector 146_i is connected to the anode inlet of the fuel cell stack 101_i via the second input solenoid valve 131_i, thus enabling the hydrogen supply device to... After passing through the hydrogen inlet pressure regulating chamber 142, the ejector 145_i, and the ejector 146_i in sequence, the hydrogen gas is transported to the fuel cell stack 101_i through the second input solenoid valve 131_i for electrochemical reaction. The anode outlet of the fuel cell stack 101_i is connected to the inlet of the gas-liquid separator 143 through the second output solenoid valve 132_i. The first outlet of the gas-liquid separator 143 is connected to the second inlet of the ejector 146_i. The second outlet of the gas-liquid separator 143 is connected to the atmospheric environment through the hydrogen discharge valve 144. This allows the gas-liquid separator 143 to separate the hydrogen gas discharged from the fuel cell stack 101_i into liquid water and gas, and then transport the separated hydrogen gas back to the fuel cell stack 101_i through the ejector 146_i for recycling.
[0054] Specifically, the third solenoid valve module includes a third solenoid valve group configured for each fuel cell stack 101_i, which is used to control the thermal management module to supply coolant to the fuel cell stack 101_i.
[0055] In some embodiments, see Figure 5 As shown, the third solenoid valve group configured for each fuel cell stack 101_i includes a third input solenoid valve 151_i and a third output solenoid valve 152_i. The coolant inlet of the fuel cell stack 101_i is connected to the thermal management module through the third input solenoid valve 151_i, and the coolant outlet of the fuel cell stack 101_i is connected to the thermal management module through the third output solenoid valve 152_i. By setting the third input solenoid valve 151_i at the coolant inlet of the fuel cell stack 101_i and the third output solenoid valve 152_i at the coolant outlet of the fuel cell stack 101_i, it is beneficial to more effectively cut off and control the coolant supply process of the fuel cell stack 101_i, ensuring that no coolant enters when the fuel cell stack 101_i is shut down.
[0056] In some embodiments, see Figure 5As shown, the thermal management module includes an expansion tank 161, an electric water pump 162, an electronic thermostat 163, a deionizer 164, and a radiator 165. A fan is installed on the radiator 165 to improve heat dissipation efficiency. A third input solenoid valve 151_i and a third output solenoid valve 152_i are configured for each fuel cell stack 101_i. The outlet of the expansion tank 161 is connected to the inlet of the electric water pump 162, and the outlet of the electric water pump 162 is connected to the third input solenoid valve 151_i. The coolant inlet of the fuel cell stack 101_i is connected, and the coolant outlet of the fuel cell stack 101_i is connected to the inlet of the electronic thermostat 163 through the third output solenoid valve 152_i. The first outlet of the electronic thermostat 163 is connected to the inlet of the deionizer 164, and the outlet of the deionizer 164 is connected to the inlet of the electric water pump 162. The second outlet of the electronic thermostat 163 is connected to the inlet of the radiator 165, and the outlet of the radiator 165 is connected to the inlet of the electric water pump 162.
[0057] The multi-stack series controllable fuel cell system provided in this application embodiment, when multiple stacks are electrically connected in series, allows multiple stacks to operate simultaneously to achieve high power output. This is achieved by configuring a dual-switch unit for each stack to control the power output received from the high-voltage power module, configuring a first solenoid valve group for each stack to control the connection between the stack and the air supply module, configuring a second solenoid valve group for each stack to control the connection between the stack and the hydrogen supply module, and configuring a third solenoid valve group for each stack to control the connection between the stack and the thermal management module. This allows some stacks to operate simultaneously when power demand is relatively low to avoid carbon corrosion and other degradation phenomena caused by the fuel cell system being at a high potential. This ensures a wide power output range for the fuel cell system and improves its operational lifespan.
[0058] Figure 6 This is a schematic diagram of an optional closed-cell control method provided in an embodiment of this application, mainly applied to the aforementioned multi-stack series controllable fuel cell system. Figure 6 The method may include, but is not limited to, steps S201 to S204:
[0059] Step S201: When multiple electrically connected fuel cells are in normal working condition, obtain the current power requirement of the entire vehicle;
[0060] Step S202: Determine the number of fuel cells that need to be shut down based on the current power demand of the vehicle.
[0061] Step S203: When the number of fuel cell stacks is greater than zero, obtain the historical operating parameter values of multiple fuel cell stacks;
[0062] Step S204: Based on the number of fuel cell stacks and the historical operating parameter values of multiple fuel cell stacks, select all target fuel cell stacks that need to be shut down from multiple fuel cell stacks, and then control all target fuel cell stacks to perform shutdown operations.
[0063] In step S201 of some embodiments, each fuel cell stack being in normal operating condition includes: a first relay switch configured for the fuel cell stack being in a closed state, a second relay switch configured for the fuel cell stack being in a closed state, a first solenoid valve group configured for the fuel cell stack being in an open state at a preset opening degree, and a second solenoid valve group and a third solenoid valve group configured for the fuel cell stack being in a fully open state; wherein, the preset opening degree of the first solenoid valve group is preferably set to 80%, which can constrain the air supply module to provide an appropriate flow of air to the fuel cell stack, prevent the fuel cell stack from aging too quickly, and also help control the temperature of the fuel cell stack.
[0064] Specifically, in combination Figures 2 to 5 Each fuel cell stack 101_i is controlled to be in normal working condition at least in the following ways: First, the first relay switch S1_i configured for the fuel cell stack 101_i is controlled to be closed, and the second relay switch S2_i configured for the fuel cell stack 101_i is controlled to be open; Second, the first input solenoid valve 111_i and the first output solenoid valve 112_i configured for the fuel cell stack 101_i are controlled to be open at the preset opening degree, and the air compressor 121 is controlled to operate at the required speed as pre-calibrated; Third, the second input solenoid valve 131_i and the second output solenoid valve 112_i configured for the fuel cell stack 101_i are controlled to be open. The output solenoid valve 132_i is in a fully open state (i.e., the opening degree is 100%), and the hydrogen injection valve 141 is controlled to operate according to the first pre-calibrated demand conditions, which may include hydrogen flow rate, hydrogen pressure, the opening and closing response time of the hydrogen injection valve 141, and the opening degree, etc.; Fourth, the third input solenoid valve 151_i and the third output solenoid valve 152_i configured for the fuel cell stack 101_i are controlled to be in a fully open state (i.e., the opening degree is 100%), and the electric water pump 162 is controlled to operate according to the second pre-calibrated demand conditions, which may include the speed requirements of the motor configured for the electric water pump 162, etc.
[0065] In step S201 of some embodiments, the current vehicle power demand is directly provided by the vehicle controller, which can be understood as the power demand command issued by the vehicle controller to the fuel cell engine based on the current vehicle operating status and / or driver operation.
[0066] In step S202 of some embodiments, a preset table can be consulted. The preset table records multiple consecutive non-overlapping vehicle power demand ranges and the number of fuel cell stacks working for each vehicle power demand range. First, the vehicle power demand range to which the current vehicle power demand belongs is selected from the preset table. Then, the number of all fuel cell stacks currently in normal working condition is subtracted from the number of fuel cell stacks working for the selected vehicle power demand range to obtain the number of fuel cell stacks that need to be shut down.
[0067] For example, when the aforementioned multi-stack series controllable fuel cell system is applied to a long-haul tractor, since long-haul tractors are generally equipped with 360kW fuel cell engines, it is necessary to design 6 fuel cell stacks in the multi-stack series controllable fuel cell system. A preset table is set and named the "Vehicle Power Demand - Number of Fuel Cell Stacks Operating Rule Table" (see Table 1). If the current vehicle power demand issued by the vehicle controller falls within the range of (240kW, 300kW), it means that only 5 fuel cell stacks need to operate in the multi-stack series controllable fuel cell system. In this case, it is determined that the number of fuel cell stacks that need to be shut down is 1, ensuring that the fuel cell operates in a quasi-steady-state state within the single-cell voltage range of 0.7V-0.8V, thereby significantly improving the service life of the fuel cell. If the current vehicle power demand issued by the vehicle controller falls within the range of (300kW, 360kW), it means that 6 fuel cell stacks need to operate in the multi-stack series controllable fuel cell system, and no stack shutdown operation is required.
[0068] Table 1. Rules for Vehicle Power Requirements and Fuel Cell Quantity
[0069] Vehicle power requirement range Number of fuel cell stacks (0kW, 60kW) 1 (60kW, 120kW) 2 (120kW, 180kW) 3 (180kW, 240kW) 4 (240kW, 300kW) 5 (300kW, 360kW) 6
[0070] In step S204 of some embodiments, the historical operating parameter values of multiple fuel cell stacks include the historical operating duration of multiple fuel cell stacks, which can be provided by the FCU (Fuel Cell Control Unit) device; based on the number of fuel cell stacks that need to be shut down now and the historical operating parameter values of multiple fuel cell stacks, all target fuel cell stacks that need to be shut down now are selected from the multiple fuel cell stacks. The corresponding implementation method is as follows:
[0071] Select all fuel cell stacks with the longest historical operating time from multiple fuel cell stacks that match the number of fuel cell stacks that need to be shut down now, and then use all the selected fuel cell stacks as the target fuel cell stacks that need to be shut down now.
[0072] Specifically, the number of battery stacks that need to be shut down is denoted as K. The battery stacks are arranged in descending order of their historical operating time, and the K battery stacks at the top of the list are taken as the target battery stacks that need to be shut down. Alternatively, the battery stacks are arranged in ascending order of their historical operating time, and the K battery stacks at the bottom of the list are taken as the target battery stacks that need to be shut down.
[0073] When it is determined that a reactor shutdown operation needs to be performed based on the current power demand of the vehicle, prioritizing the shutdown of reactors with longer historical operating times helps to balance the total operating time of each reactor.
[0074] In step S204 of some embodiments, the historical operating parameter values of multiple fuel cell stacks include the average individual cell voltage of the multiple fuel cell stacks, which can be provided by the FCU device. The average individual cell voltage of each fuel cell stack mainly reflects the performance degradation degree of the fuel cell stack, which is obtained by dividing the total output voltage of the fuel cell stack in a specific state by the number of all cells contained in the fuel cell stack. The specific state can be understood as the vehicle's most recent idling state. Based on the number of fuel cell stacks that need to be shut down and the historical operating parameter values of multiple fuel cell stacks, all target fuel cell stacks that need to be shut down are selected from the multiple fuel cell stacks. The corresponding implementation method is as follows:
[0075] Select all fuel cell stacks with the lowest average individual voltage from multiple stacks that match the number of stacks that need to be shut down. Then, select all the stacks that need to be shut down as the target stacks.
[0076] Specifically, the number of battery stacks that need to be shut down is denoted as K. The multiple battery stacks are arranged in descending order of average individual voltage, and the last K battery stacks are selected as the target battery stacks that need to be shut down. Alternatively, the multiple battery stacks are arranged in ascending order of average individual voltage, and the first K battery stacks are selected as the target battery stacks that need to be shut down.
[0077] When it is determined that a reactor shutdown operation needs to be performed based on the current power demand of the vehicle, prioritizing the shutdown of reactors with lower average individual voltages helps to balance the performance degradation of each reactor, that is, to balance the output performance of each reactor under the same current.
[0078] In step S204 of some embodiments, all target fuel cells are controlled to shut down. The corresponding implementation methods include the following:
[0079] For each target fuel cell stack, the first relay switch configured for that target fuel cell stack is controlled to be in the open state, and the second relay switch configured for that target fuel cell stack is controlled to be in the closed state; the first solenoid valve group configured for that target fuel cell stack is controlled to be in the fully open state, and then the air supply module is controlled to perform air purging on the target fuel cell stack for a first preset duration, that is, to constrain the air supply module to provide a large flow of air to the target fuel cell stack; the first solenoid valve group configured for that target fuel cell stack is controlled to be in the fully closed state, and then the target fuel cell stack is controlled to perform oxygen-consuming discharge for a second preset duration; the second solenoid valve group configured for that target fuel cell stack is controlled to be in the fully closed state, and then after a third preset duration, the third solenoid valve group configured for that target fuel cell stack is controlled to be in the fully closed state.
[0080] Wherein, the second preset duration is less than the third preset duration, and the third preset duration is less than or equal to the first preset duration; preferably, the first preset duration is selected within the range of [20s, 40s], the second preset duration is selected within the range of [3s, 5s], and the third preset duration is set to 20s.
[0081] For example, combined Figures 2 to 5 When it is determined that fuel cell stack 101_1 is the target fuel cell stack that needs to be shut down, the first relay switch S1_1 configured for fuel cell stack 101_1 is controlled to be in the open state, and the second relay switch S2_1 configured for fuel cell stack 101_1 is controlled to be in the closed state. At this time, the DC-DC converter performs voltage regulation. The first input solenoid valve 111_1 and the first output solenoid valve 112_1 configured for fuel cell stack 101_1 are controlled to be in the fully open state (i.e., the opening degree is 100%). Then, the air supply module is controlled to perform a large flow of air purging on fuel cell stack 101_1 for a first preset time. The first input solenoid valve 111_1 and the first output solenoid valve 112_1 configured for 01_1 are in a fully closed state (i.e., the opening degree is 0%), and then the fuel cell stack 101_1 is controlled to perform oxygen-consuming discharge for the second preset duration. The second input solenoid valve 131_1 and the second output solenoid valve 132_1 configured for the fuel cell stack 101_1 are controlled to be in a fully closed state (i.e., the opening degree is 0%), and then after the third preset duration, the third input solenoid valve 151_1 and the third output solenoid valve 152_1 configured for the fuel cell stack 101_1 are controlled to be in a fully closed state (i.e., the opening degree is 0%), thereby realizing the shutdown operation of the fuel cell stack 101_1.
[0082] By controlling the target fuel cell stack to perform a shutdown operation according to a specific process—first cutting off the influence of the high-voltage power module, then cutting off the influence of the air supply module, then cutting off the influence of the hydrogen supply module, and finally cutting off the influence of the thermal management module—the target fuel cell stack can safely stop the electrochemical reaction and perform effective thermal management, thereby ensuring that the target fuel cell stack is not damaged.
[0083] It should be noted that after determining all target fuel cells that need to be shut down, all target fuel cells can be shut down simultaneously; alternatively, a sequence can be determined based on the historical operating parameter values of all target fuel cells, and then all target fuel cells can be shut down in that sequence.
[0084] Specifically, in some embodiments, the historical operating parameter values of all target stacks include the historical operating time of all target stacks. A priority order is determined based on the historical operating time of all target stacks. This priority order is mainly used to prioritize the shutdown of target stacks with relatively longer historical operating times, and then control all target stacks to perform shutdown operations according to this priority order.
[0085] Specifically, in some embodiments, the historical operating parameter values of all target stacks include the average individual voltage of all target stacks. A priority order is determined based on the average individual voltage of all target stacks. This priority order is mainly used to prioritize the shutdown of target stacks with relatively small average individual voltages, and then control all target stacks to perform shutdown operations according to this priority order.
[0086] The reactor shutdown control method proposed in this application determines the target reactor that needs to be shut down based on the historical operating parameter values of multiple reactors when the power demand is relatively low, and performs shutdown operation on it, which is beneficial to balance the operating life of multiple reactors.
[0087] In addition, this application also provides a vehicle that includes the above-mentioned multi-stack series controllable fuel cell system. The vehicle generally needs to have sufficient power and range. The vehicle can be a heavy truck, such as a long-haul tractor or a mining truck, or a public bus, such as a city bus or a long-distance passenger bus. This application does not limit the vehicle in this regard.
[0088] It is understood that the content of the above system embodiments is applicable to this vehicle embodiment. The specific functions implemented in this vehicle embodiment are the same as those in the above system embodiments, and the beneficial effects achieved are also the same as those achieved in the above system embodiments.
[0089] Although the description of this application has been quite detailed and particularly focused on several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment. Rather, it should be considered as effectively covering the intended scope of this application by referring to the appended claims and taking into account the broad possible interpretations of these claims provided by the prior art. Furthermore, the foregoing description of this application with respect to embodiments foreseeable by the inventors is intended to provide a useful description, and non-substantial modifications to this application that have not yet been foreseen may still represent equivalent modifications.
Claims
1. A closed-loop control method, characterized in that, The closed-loop control method includes: When multiple electrically connected fuel cells are in normal operating condition, obtain the current power requirement of the entire vehicle; Based on the current power demand of the vehicle, determine the number of fuel cells that need to be shut down. When the number of fuel cells is greater than zero, obtain the historical operating parameter values of the multiple fuel cells; Based on the number of fuel cells and the historical operating parameter values of the multiple fuel cells, select all target fuel cells that need to be shut down from the multiple fuel cells, and then control all target fuel cells to perform shutdown operations; The step of selecting all target electric fuel cells that need to be shut down from the plurality of electric fuel cells based on the number of fuel cells and the historical operating parameter values of the plurality of fuel cells includes: The historical operating parameter values of the multiple fuel cell stacks include the historical operating time of the multiple fuel cell stacks. Select all fuel cell stacks with the longest historical operating time that match the number of fuel cell stacks from the multiple fuel cell stacks. Select all the selected fuel cell stacks as the target fuel cell stacks that need to be shut down. Alternatively, the historical operating parameter values of the multiple stacks include the average individual voltage of the multiple stacks. The stacks with the lowest average individual voltage that match the number of stacks are selected from the multiple stacks, and the selected stacks are taken as the target stacks that need to be shut down.
2. The closed-loop control method according to claim 1, characterized in that, The closed-stack control method is applied to a multi-stack series controllable fuel cell system, which includes a stack module, a high-voltage power module, a dual-switch module, an air supply module, a first solenoid valve module, a hydrogen supply module, a second solenoid valve module, a thermal management module, and a third solenoid valve module. The fuel cell module includes multiple fuel cells, and the series connection between the negative terminal of each fuel cell and the positive terminal of the next fuel cell is referred to as an electrical circuit; the positive terminal of the first fuel cell is connected to the positive terminal of the high-voltage power module to form an electrical circuit, and the negative terminal of the last fuel cell is connected to the negative terminal of the high-voltage power module. The dual-switch module includes a dual-switch unit configured for each of the fuel cell stacks. The dual-switch unit includes a first relay switch and a second relay switch. The first relay switch is disposed on the electrical line associated with the positive terminal of the fuel cell stack. A first terminal of the first relay switch is connected to the positive terminal of the fuel cell stack. A second terminal of the first relay switch is connected to the first terminal of the second relay switch. A second terminal of the second relay switch is connected to the negative terminal of the fuel cell stack. The first solenoid valve module includes a first solenoid valve group configured for each of the fuel cell stacks, the first solenoid valve group being used to control the air supply module to supply air to the fuel cell stacks; The second solenoid valve module includes a second solenoid valve group configured for each of the fuel cell stacks, the second solenoid valve group being used to control the hydrogen supply module to supply hydrogen to the fuel cell stacks; The third solenoid valve module includes a third solenoid valve group configured for each of the fuel cell stacks, the third solenoid valve group being used to control the thermal management module to supply coolant to the fuel cell stacks.
3. The closed-loop control method according to claim 2, characterized in that, Each of the fuel cell stacks is in a normal operating state including: the first relay switch configured for the fuel cell stack is in a closed state, the second relay switch configured for the fuel cell stack is in a closed state, the first solenoid valve group configured for the fuel cell stack is in an open state at a preset opening degree, and the second and third solenoid valve groups configured for the fuel cell stack are in a fully open state.
4. The closed-loop control method according to claim 2, characterized in that, The process of controlling all target fuel cell stacks to shut down includes: For each target battery stack, the first relay switch configured for the target battery stack is controlled to be in the open state, and the second relay switch configured for the target battery stack is controlled to be in the closed state; The first solenoid valve group configured for the target fuel cell stack is controlled to be fully open, and then the air supply module is controlled to purge the target fuel cell stack with air for a first preset duration. The first solenoid valve group configured for the target fuel cell stack is controlled to be fully closed, and then the target fuel cell stack is controlled to perform oxygen-consuming discharge for a second preset duration. The second solenoid valve group configured for the target fuel cell stack is controlled to be fully closed, and then after a third preset time period, the third solenoid valve group configured for the target fuel cell stack is controlled to be fully closed.
5. The closed-loop control method according to claim 2, characterized in that, The first solenoid valve group configured for each of the fuel cell stacks includes a first input solenoid valve and a first output solenoid valve. The cathode inlet of the fuel cell stack is connected to the air supply module through the first input solenoid valve, and the cathode outlet of the fuel cell stack is connected to the air supply module through the first output solenoid valve.
6. The closed-loop control method according to claim 2, characterized in that, The second solenoid valve group configured for each of the fuel cell stacks includes a second input solenoid valve and a second output solenoid valve. The anode inlet of the fuel cell stack is connected to the hydrogen supply module through the second input solenoid valve, and the anode outlet of the fuel cell stack is connected to the hydrogen supply module through the second output solenoid valve.
7. The closed-loop control method according to claim 2, characterized in that, The third solenoid valve group configured for each fuel cell stack includes a third input solenoid valve and a third output solenoid valve. The coolant inlet of the fuel cell stack is connected to the thermal management module through the third input solenoid valve, and the coolant outlet of the fuel cell stack is connected to the thermal management module through the third output solenoid valve.
Citation Information
Patent Citations
Many piles fuel cell system , vehicle
CN208078097U
Fuel cell system
JP2023160041A