Stack activation system and control method

Abstract

This application relates to a fuel cell stack activation system and control method, belonging to the field of fuel cell technology. The fuel cell stack activation system can ensure normal operation by controlling the ratio of oxygen to nitrogen. The fuel cell stack activation system includes: a fuel cell stack, a cathode supply unit, an anode supply unit, and a cooling unit; a first input terminal of the fuel cell stack is connected to a first output terminal of the cathode supply unit, a second input terminal of the fuel cell stack is connected to the first output terminal of the anode supply unit, the first output terminal of the fuel cell stack is connected to an external environment or the cathode supply unit, and the second output terminal of the fuel cell stack is connected to the first input terminal of the anode supply unit; a first terminal of the cooling unit is connected to a third input terminal of the fuel cell stack, and a second terminal of the cooling unit is connected to the third output terminal of the fuel cell stack; the cathode supply unit is configured to provide the fuel cell stack with a first ratio of nitrogen and oxygen, and the anode supply unit is configured to provide the fuel cell stack with hydrogen; wherein the ratio of oxygen to nitrogen is a predetermined ratio.

Description

Technical Field

[0001] This application relates to the field of fuel cell technology, and more particularly to the field of controller technology, specifically to a fuel cell stack activation system and control method. Background Technology

[0002] As a clean, environmentally friendly, and highly efficient energy conversion device, fuel cells are increasingly being applied in various fields such as industry, transportation, and power. The performance of a fuel cell largely depends on the performance of its membrane electrode assembly (MEA), making the activation of the fuel cell and MEA crucial. Newly manufactured fuel cells undergo activation to achieve proton exchange membrane wetting, establishment of mass transport channels (including electrons, protons, gases, and water), optimization of electrode structure, and improvement of catalyst activity and utilization, allowing the MEA to perform at its best within a short period of time.

[0003] Currently, oxygen, nitrogen, and hydrogen are used in the activation methods of fuel cell stacks. However, it is difficult to balance the selection and control of gas humidity and gas metering ratio. Often, fuel cells will shut down due to "water blockage" before operating at low voltage, causing the activation of the fuel cell stack to be terminated. Summary of the Invention

[0004] This application provides a fuel cell stack activation system and control method. The activation system can be operated normally by controlling the ratio of oxygen to nitrogen. The technical solution of this application is as follows:

[0005] In a first aspect, this application provides a fuel cell stack activation system, comprising: a fuel cell stack, a cathode supply unit, an anode supply unit, and a cooling unit; a first input terminal of the fuel cell stack is connected to a first output terminal of the cathode supply unit, a second input terminal of the fuel cell stack is connected to the first output terminal of the anode supply unit, the first output terminal of the fuel cell stack is connected to an external environment or the cathode supply unit, and the second output terminal of the fuel cell stack is connected to the first input terminal of the anode supply unit; a first terminal of the cooling unit is connected to a third input terminal of the fuel cell stack, and a second terminal of the cooling unit is connected to the third output terminal of the fuel cell stack; the cathode supply unit is configured to provide the fuel cell stack with a first ratio of nitrogen and oxygen, and the anode supply unit is configured to provide the fuel cell stack with hydrogen; wherein the ratio of oxygen to nitrogen is a predetermined ratio.

[0006] Based on the above scheme, some embodiments of this application provide a fuel cell stack activation system. The system provides oxygen and nitrogen to the fuel cell stack at a first ratio through a cathode supply unit and hydrogen through an anode supply unit. The oxygen and hydrogen undergo an electrochemical reaction inside the fuel cell stack to generate electricity. By changing the value of the first ratio, the fuel cell stack activation efficiency can be improved, and a large amount of water generated by the electrochemical reaction can be discharged, thereby protecting the components inside the self-humidifying fuel cell stack and ultimately ensuring the normal operation of the fuel cell stack activation process.

[0007] In one possible implementation, the fuel cell stack activation system further includes: a control unit; a first control terminal of the control unit is connected to the cathode supply unit, and a second control terminal of the control unit is connected to the anode supply unit; the control unit is configured to calculate the concentration of oxygen and nitrogen in the cathode supply unit and control and change the first ratio.

[0008] Based on the aforementioned technical means, the control unit in this application can control the ratio of oxygen to nitrogen content output by the cathode supply unit.

[0009] In one possible implementation, the cathode supply unit includes an oxygen tank, a nitrogen tank, a gas mixing unit, and a first humidifier; the anode supply unit includes a hydrogen tank and a second humidifier; the output of the oxygen tank is connected to a first input of the gas mixing unit, the output of the nitrogen tank is connected to a second input of the gas mixing unit, and the output of the nitrogen tank is also connected to the input of the second humidifier; the input of the first humidifier is connected to the output of the gas mixing unit, and the output of the first humidifier is connected to the first input of the cathode supply unit; the nitrogen tank is configured to output nitrogen to the first and second humidifiers to generate humidified nitrogen, and the humidified nitrogen is transmitted to the fuel cell stack for wetting through the first output of the cathode supply unit and the first output of the anode supply unit.

[0010] According to the above-mentioned technical means, in this application, nitrogen is humidified by a first humidifier and a second humidifier, and then the nitrogen is transferred to the fuel cell stack for wetting, which is conducive to the electrochemical reaction and improves the activation efficiency and power generation efficiency of the fuel cell stack.

[0011] In one possible implementation, the cathode supply unit further includes: a first voltage regulator, a first pressure sensor 13, and a second pressure sensor; the anode supply unit includes: a second voltage regulator; the input terminal of the first voltage regulator is connected to the output terminal of the gas mixing unit; the output terminal of the first voltage regulator is connected to the input terminal of the first humidifier; the first pressure sensor is disposed between the first voltage regulator and the first humidifier, and the second pressure sensor is disposed on the first output terminal of the fuel cell stack; the second voltage regulator is disposed between the second humidifier and the hydrogen tank; the first pressure sensor and the second pressure sensor are configured to detect gas pressure in real time and transmit the detected first pressure value and second pressure value to the control unit.

[0012] Based on the aforementioned technical means, this application uses a first voltage regulator and a second voltage regulator to adjust the pressure of the cathode supply unit and the anode supply unit, preparing for the wetting of the fuel cell stack. Simultaneously, the first and second pressure sensors can detect the pressure at the inlet and outlet of the cathode supply unit in real time, thereby calculating the flow resistance. Using the flow rate value corresponding to the stable flow resistance as a reference flow rate value, the oxygen content is reduced to lower the voltage while maintaining the reference flow rate value constant, creating a reducing environment and improving the fuel cell stack activation efficiency.

[0013] In one possible implementation, the anode supply unit further includes a third pressure sensor and a fourth pressure sensor; the third pressure sensor is disposed between the second humidifier and the second voltage regulator, and the fourth pressure sensor is disposed on the second output terminal of the fuel cell stack; the third pressure sensor and the fourth pressure sensor are configured to detect the gas pressure in the cathode supply unit in real time and transmit the detected third pressure value and fourth pressure value to the control unit.

[0014] Based on the above-mentioned technical means, the third and fourth pressure sensors in this application can detect the gas pressure in the anode supply unit in real time, preventing excessive or insufficient pressure from affecting the operation of the fuel cell stack.

[0015] Secondly, this application provides a control method for a fuel cell stack activation system, which is applied to the aforementioned fuel cell stack activation system.

[0016] The cathode supply unit provides the fuel cell stack with a first ratio of nitrogen and oxygen, and the anode supply unit provides the fuel cell stack with hydrogen. As the load density gradually increases, the control unit adjusts the ratio of nitrogen and oxygen accordingly, gradually reducing the oxygen content and increasing the nitrogen content. After the fuel cell stack stabilizes at the set density point, the gas volume remains constant, and the load is reduced to the initial density point corresponding to the first ratio. The above steps are repeated to gradually reduce the oxygen content and increase the nitrogen content.

[0017] According to the aforementioned technical means, in this application, the cathode supply unit provides nitrogen and oxygen to the fuel cell stack, and the anode supply unit provides hydrogen, thereby triggering a chemical reaction and initiating the fuel cell stack's operation. The pressure at the inlet and outlet of the cathode supply unit can be monitored in real time using a first pressure sensor and a second pressure sensor, allowing for the calculation of the flow resistance. Using the flow rate value corresponding to a stable flow resistance as a reference flow rate, the control unit reduces the oxygen content to lower the voltage, creating a reducing environment and improving the fuel cell stack activation efficiency while maintaining the reference flow rate constant. After the fuel cell stack stabilizes at the fourth electrical density point, the water content within the stack is relatively high. Maintaining the current gas flow rate, the control unit reduces the load, decreases the current, and reduces water production, effectively increasing the drainage effect and further protecting the fuel cell stack. This process is cyclical, with the control unit managing the strategy between the fuel cell stack activation environment and drainage, while simultaneously optimizing the internal electrode structure of the fuel cell stack to ensure effective activation.

[0018] In one possible implementation, when the cathode supply unit includes an oxygen tank, a nitrogen tank, a gas mixing unit, and a first humidifier, and the anode supply unit includes a hydrogen tank and a second humidifier, before the cathode supply unit supplies a first ratio of nitrogen and oxygen to the fuel cell stack, the nitrogen tank outputs nitrogen to the first and second humidifiers to generate humidified nitrogen. The humidified nitrogen is then transmitted to the fuel cell stack for wetting via the first output terminals of the cathode supply unit and the anode supply unit.

[0019] According to the above-mentioned technical means, in this application, nitrogen gas is humidified by a first humidifier and a second humidifier, and then the nitrogen gas is transferred to the fuel cell stack for wetting, which is conducive to the electrochemical reaction and improves the working efficiency of the fuel cell stack.

[0020] In one possible implementation, the control unit closes the load, applies electrical density, and operates stably at the initial electrical density point, thus wetting the fuel cell stack.

[0021] Based on the above-mentioned technical means, the initial wetting is performed by a control unit in this application.

[0022] In one possible implementation, the control unit collects the pressure at the inlet and outlet of the cathode supply unit during operation using a first pressure sensor and a second pressure sensor, and calculates the flow resistance. Using the flow rate value corresponding to the average flow resistance and the absolute value of the oxygen flow rate at the initial electrical density point as a benchmark, the control unit gradually reduces the oxygen content and adjusts the ratio of nitrogen to oxygen, and then operates stably at different electrical density points in sequence. When the control unit detects that the unit has reached a certain electrical density point and the individual cell voltage has reached the preset protection voltage, it increases the oxygen content and records it, replacing the metering ratio at that electrical density point. The above steps are repeated until the voltage at each electrical density point is within the set error voltage of the previous round, thus completing the activation.

[0023] Based on the aforementioned technical means, this application first collects the pressure at the inlet and outlet of the cathode supply unit using a first pressure sensor and a second pressure sensor, and transmits the first and second pressure values ​​to the control unit. The control unit calculates the flow resistance using the pressure difference, and the stabilized flow resistance is used as the average flow resistance. The flow rate value corresponding to this average flow resistance and the oxygen flow rate value are considered as the reference flow rate value. Then, the oxygen content is gradually reduced in a decreasing manner. While the total flow rate remains constant, the ratio of oxygen to nitrogen decreases, and the system operates stably at different electrical density points. Stable operation of the fuel cell stack indicates that the oxygen content is still above the standard value and will not affect the normal operation of the fuel cell stack.

[0024] In one possible implementation, during the process of gradually reducing the oxygen content, the control unit controls the oxygen content to be greater than the theoretical oxygen consumption, and replenishes the nitrogen content to the reference flow rate value.

[0025] In one possible implementation, the different electrical density points include a first electrical density point, a second electrical density point, a third electrical density point, and a fourth electrical density point; the first electrical density point is smaller than the second electrical density point, the second electrical density point is smaller than the third electrical density point, and the third electrical density point is smaller than the fourth electrical density point; wherein, the fourth electrical density point is a predetermined electrical density point.

[0026] In one possible implementation, the preset protection voltage includes a first protection voltage and a second protection voltage; when the control unit detects that the voltage of a single cell corresponding to a certain electrical density point reaches the first protection voltage, the oxygen content is increased by a second gradient value that is less than the initial reduction gradient; when the control unit detects that the voltage of a single cell corresponding to a certain electrical density point reaches the second protection voltage, the stack is shut down.

[0027] The beneficial effects of this invention are:

[0028] (1) In this application, the control unit calculates the oxygen and nitrogen concentrations required for the operation of the stack during the activation process in real time, ensuring that the gas pressure and total flow rate entering the stack from the cathode supply unit remain unchanged, thus avoiding the problem of increased flow resistance caused by increased gas flow rate during the activation process.

[0029] (2) In this application, the nitrogen content is increased by controlling the control unit, which is beneficial for the fuel cell stack to drain under high electrical density and high humidity activation conditions, and avoids damage to the fuel cell stack performance, components and materials.

[0030] (3) In this application, the control unit also monitors the operation of each unit in real time and performs corresponding PID adjustment to ensure that the activation process proceeds normally.

[0031] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit this application. Beneficial effects of the present invention: Attached Figure Description

[0032] Figure 1 This is a structural block diagram of a fuel cell stack activation system according to some embodiments;

[0033] Figure 2 This is a structural block diagram of another fuel cell stack activation system shown according to some embodiments;

[0034] Figure 3 This is an overall schematic diagram of a fuel cell stack activation system according to some embodiments;

[0035] Figure 4 This is a flowchart illustrating a control method for a fuel cell stack activation system according to some embodiments;

[0036] Figure 5 This is a flowchart illustrating another method for controlling a fuel cell stack activation system according to some embodiments;

[0037] Figure 6 This is a flowchart illustrating yet another method for controlling a fuel cell stack activation system, based on some embodiments.

[0038] Among them, 1-fuel cell stack; 2-cathode supply unit; 21-oxygen tank; 22-nitrogen tank; 23-gas mixing unit; 24-first humidifier; 25-first voltage regulator; 26-first pressure sensor; 27-second pressure sensor; 28-heat exchanger; 3-anode supply unit; 31-hydrogen tank; 32-second humidifier; 33-second voltage regulator; 34-third pressure sensor; 35-fourth pressure sensor; 36-pressure reduction device; 4-control unit; 5-cooling unit; 61-flow meter; 62-valve; 63-temperature sensor; 64-dew point temperature detector; 65-heat tracing cable; 100-fuel cell stack activation system. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0040] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0041] As a clean, environmentally friendly, and highly efficient energy conversion device, fuel cells are increasingly being applied in various fields such as industry, transportation, and power. The performance of a fuel cell largely depends on the performance of its membrane electrode assembly (MEA), making the activation of the fuel cell and MEA crucial. Newly manufactured fuel cells undergo activation to achieve proton exchange membrane wetting, establishment of mass transport channels (including electrons, protons, gases, and water), optimization of electrode structure, and improvement of catalyst activity and utilization, allowing the MEA to perform at its best within a short period of time.

[0042] Currently, oxygen, nitrogen, and hydrogen are used in the activation methods of fuel cell stacks. However, it is difficult to balance the selection and control of gas humidity and gas metering ratio. Often, fuel cells will shut down due to "water blockage" before operating at low voltage, causing the activation of the fuel cell stack to be terminated.

[0043] It should be noted that in some embodiments, the aforementioned fuel cell stack is a self-humidifying stack. A self-humidifying stack utilizes water generated by internal reactions to wet the stack, resulting in stronger water retention but relatively higher flow resistance. Excessive gas-side flow resistance leads to an excessive pressure difference across the proton exchange membrane, causing uneven membrane stress, resulting in membrane perforation and microcracks. To rapidly wet the proton exchange membrane during activation and establish mass transport channels, optimize electrode structure, and improve catalyst activity and utilization, mechanical methods are less effective and may even damage the fuel cell stack.

[0044] Based on this, this application provides a fuel cell stack activation system. For example... Figure 1 As shown, the fuel cell stack activation system 100 includes: fuel cell stack 1, cathode supply unit 2 and anode supply unit 3.

[0045] The first input terminal 101 of the fuel cell stack 1 is connected to the first output terminal of the cathode supply unit 2, the second input terminal 102 of the fuel cell stack 1 is connected to the first output terminal of the anode supply unit 3, the first output terminal 111 of the fuel cell stack 1 is connected to the outside, and the second output terminal 112 of the fuel cell stack 1 is connected to the first input terminal of the anode supply unit 3.

[0046] The first output terminal 111 of the fuel cell stack 1 is connected to an external source or a cathode supply unit, where the external source can be a fuel cell.

[0047] The cathode supply unit 2 is configured to supply nitrogen and oxygen in a first ratio to the fuel cell stack 1, and the anode supply unit 3 is configured to supply hydrogen to the fuel cell stack 1.

[0048] The ratio of oxygen to nitrogen is a predetermined ratio.

[0049] For example, the first ratio is approximately the same as air, with 80% nitrogen and 20% oxygen. A possible ratio is 2 moles of hydrogen and 1 mole of oxygen reacting.

[0050] The fuel cell stack activation system 100 also includes a cooling unit 5; the first end of the cooling unit 5 is connected to the third input end 103 of the fuel cell stack 1, and the second end of the cooling unit 5 is connected to the third output end 113 of the fuel cell stack 1.

[0051] According to the above-mentioned technical means, the cooling unit 5 in this application cools down the fuel cell stack 1 when it is working, removes the excess heat of the fuel cell stack 1 when it is working, and maintains the working temperature of the fuel cell stack.

[0052] In some embodiments, the first end of the cooling unit 5 transmits coolant to the third input end 103 of the fuel cell stack 1. The coolant passes through the fuel cell stack 1, carrying away the heat generated during the operation of the fuel cell stack. The high-temperature coolant is then transmitted to the second end of the cooling unit 5 through the third output end 113 of the fuel cell stack 1 for cooling. The cooled coolant is then transmitted to the third input end 103 of the fuel cell stack 1, and so on, cooling the fuel cell stack in a cyclic manner.

[0053] Based on the above scheme, some embodiments of this application provide a fuel cell stack activation system. The system provides oxygen and nitrogen to the fuel cell stack at a first ratio through a cathode supply unit and hydrogen through an anode supply unit. The oxygen and hydrogen undergo an electrochemical reaction inside the fuel cell stack to generate electricity. By changing the value of the first ratio, the fuel cell stack activation efficiency can be improved, and a large amount of water generated by the electrochemical reaction can be discharged, thereby protecting the components inside the self-humidifying fuel cell stack and ultimately ensuring the normal operation of the fuel cell stack activation process.

[0054] like Figure 2 As shown, in one possible implementation, the fuel cell activation system 100 further includes a control unit 4.

[0055] The first control terminal 401 of the control unit 4 is connected to the cathode supply unit 2, and the second control terminal 402 of the control unit 4 is connected to the anode supply unit 3.

[0056] The control unit 4 is configured to calculate the concentration of oxygen and nitrogen in the cathode supply unit 2 and control and change the first ratio.

[0057] According to the above-mentioned technical means, the control unit 4 in this application can control the ratio of oxygen and nitrogen content output by the cathode supply unit 2, that is, control the value of the first ratio.

[0058] like Figure 3 As shown, the cathode supply unit 2 includes: an oxygen tank 21, a nitrogen tank 22, a gas mixing unit 23, and a first humidifier 24.

[0059] The anode supply unit 3 includes: a hydrogen tank 31 and a second humidifier 32.

[0060] The output of oxygen tank 21 is connected to the first input of mixing unit 23, the output of nitrogen tank 22 is connected to the second input of mixing unit 23, and the output of nitrogen tank 22 is also connected to the input of second humidifier 32.

[0061] The input terminal of the first humidifier 24 is connected to the output terminal of the mixing unit 23, and the output terminal of the first humidifier 24 is connected to the first input terminal of the cathode supply unit 2.

[0062] Nitrogen tank 22 is configured to output nitrogen to the first humidifier 24 and the second humidifier 32 to generate humidified nitrogen. The humidified nitrogen is transmitted to the fuel cell stack 1 through the first output terminal of the cathode supply unit 2 and the first output terminal of the anode supply unit 3 for wetting.

[0063] In some embodiments, the humidity range of the humidifying nitrogen gas is 70-100% RH.

[0064] The mixing unit 23 mixes the oxygen supplied by the oxygen tank 21 and the nitrogen supplied by the nitrogen tank 22 together. The first humidifier 24 mainly humidifies the nitrogen.

[0065] It should be noted that humidified nitrogen purging can effectively remove residual moisture, oxygen, and other impurities from inside the fuel cell stack, thereby keeping the stack clean. This can prevent oxidation reactions, maintain stack performance, and extend its service life.

[0066] Meanwhile, humidified nitrogen provides the necessary humidity to the fuel cell stack during the purging process. Appropriate humidity helps maintain the stack's output characteristics and prevents problems such as proton exchange membrane drying and detachment caused by excessively low humidity. Humidification also helps prevent issues such as water blockage in individual cells and low output voltage caused by excessively high humidity.

[0067] According to the above-mentioned technical means, in this application, nitrogen gas is humidified by the first humidifier 24 and the second humidifier 32, and then the nitrogen gas is transferred to the fuel cell stack 1 to ensure that the proton exchange membrane is sufficiently wetted, which is conducive to the electrochemical reaction and improves the activation efficiency of the fuel cell stack 1.

[0068] like Figure 3 As shown, the cathode supply unit 2 also includes: a first voltage regulator 25, a first pressure sensor 26, and a second pressure sensor 27.

[0069] The anode supply unit 3 includes: a second voltage regulator 33.

[0070] The input terminal of the first pressure stabilizing device 25 is connected to the output terminal of the mixing unit 23; the output terminal of the first pressure stabilizing device 25 is connected to the input terminal of the first humidifier 24.

[0071] The first pressure sensor 26 is disposed between the first voltage regulator 25 and the first humidifier 24, and the second pressure sensor 27 is disposed on the first output terminal of the fuel cell stack 1.

[0072] The second voltage regulator 33 is located between the second humidifier 32 and the hydrogen tank 31.

[0073] The first pressure sensor 26 and the second pressure sensor 27 are configured to detect gas pressure in real time and transmit the detected first pressure value and second pressure value to the control unit 4.

[0074] Based on the aforementioned technical means, in this application, the pressure of the cathode supply unit 2 and the anode supply unit 3 is adjusted by the first voltage stabilizing device 25 and the second voltage stabilizing device 33 to prepare for wetting of the fuel cell stack 1. Simultaneously, the pressure at the inlet and outlet of the cathode supply unit 2 can be detected in real time by the first pressure sensor 26 and the second pressure sensor 27, thereby calculating the flow resistance. Using the flow rate value corresponding to the stable flow resistance as a reference flow rate value, the oxygen content is reduced to lower the voltage while maintaining the reference flow rate value constant, thus improving the activation effect of the fuel cell stack 1.

[0075] like Figure 3 As shown, the anode supply unit 3 also includes a third pressure sensor 34 and a fourth pressure sensor 35; the third pressure sensor 34 is disposed between the second humidifier 32 and the second voltage regulator 33, and the fourth pressure sensor 35 is disposed on the second output terminal of the fuel cell stack 1; the third pressure sensor 34 and the fourth pressure sensor 35 are configured to detect the gas pressure in the cathode supply unit 2 in real time, and transmit the detected third pressure value and fourth pressure value to the control unit.

[0076] Based on the above technical means, the third pressure sensor 34 and the fourth pressure sensor 35 in this application can detect the gas pressure in the anode supply unit 3 in real time, so as to prevent the pressure from being too high or too low and affecting the operation of the fuel cell stack 1.

[0077] In some embodiments, refer to Figure 3 The anode supply unit 3 also includes a step-down device 36.

[0078] The pressure reduction device 36 is located between the second pressure stabilizing device 33 and the hydrogen tank 31, and the pressure reduction device 36 is configured to meet the hydrogen pressure requirements of the reactor.

[0079] In some embodiments, refer to Figure 3 The cathode supply unit 2 also includes a heat exchange device 28.

[0080] A heat exchange device 28 is disposed between the first humidifier 24 and the fuel cell stack 1, and the heat exchange device 28 is configured to exchange heat with the transmitted gas.

[0081] In some embodiments, refer to Figure 3 The fuel cell stack activation system 100 also includes: multiple flow meters 61, multiple valves 62, multiple temperature sensors 63, multiple dew point temperature detectors 64, and multiple heating cables 65.

[0082] Among them, the valve 62 connecting the nitrogen tank and the anode supply unit 3 is a three-way valve; the three-way valve can connect the nitrogen tank and the mixing unit, and can also connect the nitrogen tank and the second pressure stabilizing device, and the two will not affect each other and can work independently.

[0083] Electric heat tracing cable 65, also known as electric heat tracing cable, is a heat-generating insulation product that generates heat when electricity is applied. It is mainly used to provide direct or indirect heat compensation for pipes, tanks, or equipment to achieve the effects of heat tracing, insulation, and antifreeze.

[0084] This application also provides a control method for a fuel cell stack activation system, which is applied to the aforementioned fuel cell stack activation system 100. The specific process is as follows (refer to...). Figure 4 ):

[0085] S101, cathode supply unit 2 provides nitrogen and oxygen in a first ratio to fuel cell stack 1, and anode supply unit 3 provides hydrogen to fuel cell stack 1.

[0086] S102 and control unit 4 adjust the ratio of nitrogen and oxygen as the load voltage gradually increases, gradually reducing the oxygen content and increasing the nitrogen content.

[0087] S103. After the fuel cell stack has been operating stably at the set electrical density point, the gas volume is kept constant and the load is reduced to the initial electrical density point corresponding to the first ratio.

[0088] S104. Repeat the above steps to gradually reduce the oxygen content and increase the nitrogen content.

[0089] According to the aforementioned technical means, in this application, the cathode supply unit provides nitrogen and oxygen to the fuel cell stack, and the anode supply unit provides hydrogen, thereby triggering a chemical reaction and initiating the fuel cell stack's operation. The pressure at the inlet and outlet of the cathode supply unit can be monitored in real time using a first pressure sensor and a second pressure sensor, allowing for the calculation of the flow resistance. Using the flow rate value corresponding to a stable flow resistance as a reference flow rate, the control unit reduces the oxygen content to lower the voltage, creating a reducing environment and improving the fuel cell stack activation efficiency while maintaining the reference flow rate constant. After the fuel cell stack stabilizes at the fourth electrical density point, the water content inside the stack is relatively high. Maintaining the current gas flow rate, the control unit reduces the load, decreases the current, and reduces water production, effectively increasing the drainage effect and further protecting the fuel cell stack. This process is cyclical, with the control unit managing the strategy between the fuel cell stack activation environment and drainage, while simultaneously optimizing the internal electrode structure of the fuel cell stack to ensure effective activation.

[0090] Before the cathode supply unit 2 supplies the first ratio of nitrogen and oxygen to the fuel cell stack 1 (see reference). Figure 5 ):

[0091] S201, nitrogen tank 22 outputs nitrogen to the first humidifier 24 and the second humidifier 32 to produce humidifying nitrogen.

[0092] S202, Humidifying nitrogen gas is transmitted to the fuel cell stack 1 through the first output terminal of the cathode supply unit 2 and the first output terminal of the anode supply unit 3 for wetting.

[0093] According to the above-mentioned technical means, in this application, nitrogen gas is humidified by the first humidifier 24 and the second humidifier 32, and then the nitrogen gas is transferred to the fuel cell stack 1 for wetting, which is conducive to the electrochemical reaction and improves the working efficiency of the fuel cell stack 1.

[0094] In one possible implementation, the control unit 4 closes the load, applies electrical density, and operates stably at the initial electrical density point, thus wetting the fuel cell stack 1.

[0095] Based on the above-mentioned technical means, the initial wetting is performed by the control unit 4 in this application.

[0096] like Figure 6 As shown, the specific control process for fuel cell stack activation is as follows:

[0097] S301, the control unit 4 collects the pressure at the inlet and outlet of the cathode supply unit 2 during operation through the first pressure sensor 26 and the second pressure sensor 27, and calculates the flow resistance.

[0098] S302. Using the average flow resistance corresponding to the flow rate and the absolute value of the oxygen flow rate at the initial electrical density point as a benchmark, gradually reduce the oxygen content and adjust the ratio of nitrogen and oxygen, and then operate stably at different electrical density points in sequence.

[0099] S303 and Control Unit 4 detect when the system reaches a certain electrical density point and the unit voltage reaches the preset protection voltage, increase the oxygen content and record it, and replace the metering ratio of that electrical density point.

[0100] S304. Repeat the above steps until the voltage of each electrical density point is within the set error voltage of the previous round, and the activation is completed.

[0101] According to the aforementioned technical means, in this application, the pressure at the inlet and outlet of the cathode supply unit 2 is first collected by the first pressure sensor 26 and the second pressure sensor 27, and the first pressure value and the second pressure value are transmitted to the control unit 4. The control unit 4 can calculate the flow resistance through the pressure difference, and the stabilized flow resistance is used as the average flow resistance. The flow rate value and oxygen flow rate value corresponding to the average flow resistance are regarded as the reference flow rate value. Then, the oxygen content is gradually reduced in a decreasing manner. With the total flow rate remaining unchanged, the ratio of oxygen to nitrogen decreases, and the system operates stably at different electrical density points in sequence. The stable operation of the fuel cell stack 1 indicates that the oxygen content is still above the standard value and will not affect the normal operation of the fuel cell stack 1.

[0102] In one possible implementation, during the process of gradually reducing the oxygen content, the control unit 4 controls the oxygen content to be greater than the theoretical oxygen consumption, and replenishes the nitrogen content to the reference flow rate value.

[0103] In one possible implementation, the different electrical density points include a first electrical density point, a second electrical density point, a third electrical density point, and a fourth electrical density point; the first electrical density point is smaller than the second electrical density point, the second electrical density point is smaller than the third electrical density point, and the third electrical density point is smaller than the fourth electrical density point.

[0104] The fourth electrical density point is the aforementioned set electrical density point, which is also the largest electrical density point.

[0105] In other words, the fuel cell stack operates stably at the first, second, third, and fourth electrical density points, respectively, representing a gradual increase in electrical density. After the stack stabilizes at the fourth electrical density point, the water content within the stack is relatively high. To maintain the current gas volume, the control unit reduces the load, decreases the current, and reduces water production, effectively increasing the drainage effect and further protecting the fuel cell stack. This process is repeated cyclically, with the control unit managing the strategy between the fuel cell stack activation environment and drainage, while simultaneously optimizing the internal electrode structure to ensure effective stack activation.

[0106] In one possible implementation, the preset protection voltage includes a first protection voltage and a second protection voltage.

[0107] When the control unit 4 detects that the voltage of a single cell corresponding to a certain electrical density point has reached the first protection voltage, it increases the oxygen content by a second gradient value that is less than the initial reduction gradient.

[0108] When the control unit 4 detects that the voltage of a single cell corresponding to a certain electrical density point reaches the second protection voltage, the fuel cell stack 1 shuts down.

[0109] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A fuel cell stack activation system (100), characterized in that, The fuel cell activation system (100) includes: a fuel cell (1), a cathode supply unit (2), an anode supply unit (3), and a cooling unit (5); The first input terminal of the fuel cell stack (1) is connected to the first output terminal of the cathode supply unit (2), the second input terminal of the fuel cell stack (1) is connected to the first output terminal of the anode supply unit (3), the first output terminal of the fuel cell stack (1) is connected to the outside or the cathode supply unit (2), and the second output terminal of the fuel cell stack (1) is connected to the first input terminal of the anode supply unit (3). The first end of the cooling unit (5) is connected to the third input end of the fuel cell stack (1), and the second end of the cooling unit (5) is connected to the third output end of the fuel cell stack (1). The cathode supply unit (2) is configured to supply nitrogen and oxygen in a first ratio to the fuel cell stack (1), and the anode supply unit (3) is configured to supply hydrogen to the fuel cell stack (1); The ratio of nitrogen to oxygen is a predetermined ratio.

2. The fuel cell stack activation system (100) according to claim 1, characterized in that, The fuel cell activation system (100) further includes: a control unit (4); The first control terminal of the control unit (4) is connected to the cathode supply unit (2), and the second control terminal of the control unit (4) is connected to the anode supply unit (3). In addition to conventional signal acquisition and control, the control unit (4) is also configured to calculate the concentration of oxygen and nitrogen in the cathode supply unit (2) and control and change the first ratio.

3. The fuel cell stack activation system (100) according to claim 2, characterized in that, The cathode supply unit (2) includes: an oxygen tank (21), a nitrogen tank (22), a gas mixing unit (23), and a first humidifier (24); the anode supply unit (3) includes: a hydrogen tank (31) and a second humidifier (32); The output end of the oxygen tank (21) is connected to the first input end of the gas mixing unit (23), the output end of the nitrogen tank (22) is connected to the second input end of the gas mixing unit (23), and the output end of the nitrogen tank (22) is also connected to the input end of the second humidifier (32). The input end of the first humidifier (24) is connected to the output end of the mixing unit (23), and the output end of the first humidifier (24) is connected to the first input end of the cathode supply unit (2); The nitrogen tank (22) is configured to output nitrogen to generate humidified nitrogen before outputting nitrogen to the first humidifier (24) and the second humidifier (32), and the humidified nitrogen is transmitted to the fuel cell stack (1) for wetting through the first output terminal of the cathode supply unit (2) and the first output terminal of the anode supply unit (3).

4. The fuel cell stack activation system (100) according to claim 3, characterized in that, The cathode supply unit (2) further includes: a first voltage regulator (25), a first pressure sensor (26), and a second pressure sensor (27); the anode supply unit (3) includes: a second voltage regulator (33); The input terminal of the first pressure regulator (25) is connected to the output terminal of the gas mixing unit (23); the output terminal of the first pressure regulator (25) is connected to the input terminal of the first humidifier (24); the first pressure sensor (26) is disposed between the first pressure regulator (25) and the first humidifier (24); the second pressure sensor (27) is disposed on the first output terminal of the fuel cell stack (1); the second pressure regulator (33) is disposed between the second humidifier (32) and the hydrogen tank (31); The first pressure sensor (26) and the second pressure sensor (27) are configured to detect gas pressure in real time and transmit the detected first pressure value and second pressure value to the control unit (4).

5. The fuel cell stack activation system (100) according to claim 4, characterized in that, The anode supply unit (3) further includes: a third pressure sensor (34) and a fourth pressure sensor (35); The third pressure sensor (34) is disposed between the second humidifier (32) and the second voltage regulator (33), and the fourth pressure sensor (35) is disposed on the second output terminal of the fuel cell stack (1); The third pressure sensor (34) and the fourth pressure sensor (35) are configured to detect the gas pressure in the cathode supply unit (2) in real time and transmit the detected third pressure value and fourth pressure value to the control unit (4).

6. A control method for a fuel cell stack activation system, characterized in that, Applied to the fuel cell stack activation system (100) as described in any one of claims 1 to 5; The cathode supply unit (2) provides the fuel cell stack (1) with a first ratio of nitrogen and oxygen, and the anode supply unit (3) provides the fuel cell stack (1) with hydrogen. As the load voltage gradually increases, the control unit (4) adjusts the ratio of nitrogen to oxygen accordingly, gradually reducing the oxygen content and increasing the nitrogen content; After the fuel cell stack (1) is running stably at the set electrical density point, the gas volume remains unchanged and the load is reduced to the initial electrical density point corresponding to the first ratio. Repeat the above steps to gradually reduce the oxygen content and increase the nitrogen content.

7. The control method according to claim 6, characterized in that, In the case where the cathode supply unit (2) includes an oxygen tank (21), a nitrogen tank (22), a gas mixing unit (23), and a first humidifier (24); and the anode supply unit (3) includes a hydrogen tank (31) and a second humidifier (32), Before the cathode supply unit (2) supplies the fuel cell stack (1) with a first ratio of nitrogen and oxygen, the nitrogen tank (22) outputs nitrogen to the first humidifier (24) and the second humidifier (32) to generate humidified nitrogen, which is then transmitted to the fuel cell stack (1) for wetting through the first output terminal of the cathode supply unit (2) and the first output terminal of the anode supply unit (3).

8. The control method according to claim 7, characterized in that, The control unit (4) closes the load, applies electrical density, and operates stably at the initial electrical density point, thus wetting the fuel cell stack (1).

9. The control method according to claim 8, characterized in that, The control unit (4) collects the pressure at the inlet and outlet of the cathode supply unit (2) during operation through the first pressure sensor (26) and the second pressure sensor (27) and calculates the flow resistance; Using the average flow resistance corresponding to the flow rate and the absolute value of oxygen flow rate at the initial electrical density point as a benchmark, the oxygen content is gradually reduced, and the ratio of nitrogen to oxygen is adjusted to achieve stable operation at different electrical density points in sequence. When the control unit (4) detects that the unit has reached a certain electrical density point and the individual cell voltage has reached the preset protection voltage, it increases the oxygen content and records it, and replaces the metering ratio of that electrical density point. Repeat the above steps until the voltage at each electrical density point is within the set error voltage range of the previous round, thus completing the activation.

10. The control method according to claim 6, characterized in that, During the process of gradually reducing the oxygen content, the control unit (4) controls the oxygen content to be greater than the theoretical oxygen consumption and replenishes the nitrogen content to the reference flow rate value.

11. The control method according to claim 9, characterized in that, The different electrical density points include a first electrical density point, a second electrical density point, a third electrical density point, and a fourth electrical density point; The first electrical density point is smaller than the second electrical density point, the second electrical density point is smaller than the third electrical density point, and the third electrical density point is smaller than the fourth electrical density point; The fourth electrical density point is the set electrical density point.

12. The control method according to claim 9, characterized in that, The preset protection voltage includes a first protection voltage and a second protection voltage; When the control unit (4) detects that the voltage of a single cell corresponding to a certain electrical density point has reached the first protection voltage, the oxygen content is increased by a second gradient value that is less than the initial reduction gradient. When the control unit (4) detects that the voltage of a single cell corresponding to a certain electrical density point reaches the second protection voltage, the stack (1) shuts down.

Images