Fuel cell system and on-line performance recovery method

Abstract

The application provides a fuel cell system and an online performance recovery method, and belongs to the technical field of fuel cells. The fuel cell system comprises a stack power generation module, an external load, a PLC control system, a hydrogen supply system and an oxygen supply system, and further comprises a membrane electrode performance recovery module, a bipolar plate performance recovery module and an IGBT control circuit which are connected with the circuit signal of the stack power generation module; the membrane electrode performance recovery module and the bipolar plate performance recovery module are connected with the circuit of a heat preservation and heat storage module and then connected with the circuit signal of the PLC system; and the IGBT control circuit is connected with the circuit signal of the PLC system. The application fully utilizes the cooperative control between the IGBT circuit control system and the PLC system, realizes real-time monitoring and automatic adjustment of the performance of the internal components of the stack while continuously supplying power, and realizes real-time online activation and rapid performance recovery through the membrane electrode performance recovery module and the bipolar plate performance recovery module when the IGBT control circuit and the PLC monitor that the performance decreases.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and more particularly to a fuel cell system and an online performance recovery method. Background Art

[0002] Fuel cells, as environmentally friendly, efficient, and long-life power generation devices, play a vital role in the energy sector. Taking the proton exchange membrane fuel cell (PEMFC) as an example, its operating principle is as follows: reactant gas enters from the anode side, where hydrogen atoms lose electrons and transform into protons. The protons pass through the proton exchange membrane to the cathode, while electrons travel through an external circuit to the cathode, where they combine with oxygen to form water. Compared to traditional power generation methods, fuel cells convert chemical energy into electrical energy in a non-combustion manner, achieving a direct power generation efficiency of up to 45%, unconstrained by the Carnot cycle. Systems centered around fuel cell stacks integrate power management and thermal management modules, offering the ability to coordinate the management of heat, electricity, water, and gas. Fuel cell system products have a wide range of applications, from fixed power stations to mobile power sources, from electric vehicles to spacecraft, and from military equipment to civilian products.

[0003] Fuel cell systems usually consist of a fuel cell stack and a BOP auxiliary system. After hydrogen and air are introduced into the system, electricity is generated to supply external loads and external circuits. The research and application of fuel cell stack activation technology is one of the important topics in the current hydrogen energy field. Activation technology directly affects the performance consistency and life of fuel cells, and therefore occupies a key position in fuel cell production. Usually, fuel cell systems will carry out additional activation steps in a targeted manner, such as proton exchange membrane humidification, establishment of material transfer channels, electrode structure optimization, and enhancement of catalyst layer activity, so that the stack reaches optimal performance. During this process, especially in alkaline anion exchange membrane fuel cells, the alkaline anion exchange groups in the polymer membrane and catalyst layer are exposed to air or oxygen for a long time, and the functional groups are easily replaced by HCO3- and CO32-, which reduces the number of anions and thus reduces the conductivity, further affecting the performance and life of the fuel cell system. Traditional online activation methods, such as constant current and variable current forced activation, achieve rapid activation by adjusting current or voltage through the connection of an external load or forced loading. However, due to the lack of effective control mechanisms and the lack of control and detection of the membrane, membrane electrode, and bipolar plates within the fuel cell stack, the system is prone to current and voltage instability during the initial load connection and the moment of forced loading startup. This leads to large load current fluctuations and localized overheating of the bipolar plates. At this time, the components within the system may suffer unnecessary stress and loss, which in turn poses a challenge to the service life of the fuel cell stack system. Therefore, it is particularly important to design a fast, safe and stable online activation system for fuel cell stacks to improve the system's response speed and stability and extend its service life. Summary of the Invention

[0004] In response to the technical problems mentioned in the above background technology, a fuel cell system and an online performance recovery method are provided. The present invention can quickly restore system performance and significantly extend service life.

[0005] The technical means adopted in the present invention are as follows:

[0006] A fuel cell system, comprising: a stack power generation module, an external load, a PLC control system, a hydrogen supply system, and an oxygen supply system, characterized in that: the stack power generation module is formed by multiple stack bodies connected in parallel, and the fuel cell system also includes a membrane electrode performance recovery module, a bipolar plate performance recovery module, and an IGBT control circuit, wherein the membrane electrode performance recovery module and the bipolar plate performance recovery module are both connected to the thermal insulation and heat storage module circuit and then connected to the PLC system circuit signal, and the IGBT control circuit is connected to the PLC system circuit signal;

[0007] The membrane electrode performance recovery module is connected to the circuit signal of the stack power generation module, and the bipolar plate performance recovery module is connected to the circuit signal of the stack power generation module.

[0008] The membrane electrode performance recovery module is provided with a drying unit and a humidifying unit, and the bipolar plate performance recovery module includes an acid / alkali solution storage unit, a drying unit and a gas storage unit;

[0009] The heat preservation and heat storage module heats the gas and liquid in the membrane electrode performance recovery module and the bipolar plate performance recovery module.

[0010] Furthermore, the gas storage unit includes a gas storage tank, a pressure gauge, a flow meter, and a hygrometer; the acid / alkali solution storage unit includes an acid / alkali solution tank, a pressure gauge, and a flow meter; the drying unit includes a limestone filtration mechanism; the humidification unit includes a humidifier, a pressure gauge, a flow meter, and a hygrometer;

[0011] Furthermore, the stack power generation module is also connected to an air filter, a temperature sensor, and an electronic radiator circuit;

[0012] The air filter, temperature sensor, electronic radiator, hydrogen supply system and air supply system are all connected to the PLC control system to realize the circuit controlled by the PLC control system;

[0013] The heat preservation and heat storage module includes a heat preservation air pump, a storage battery and a heating wire.

[0014] Furthermore, a cooling channel is provided between the anode plate and the cathode plate of the bipolar plate of the battery stack; the cooling channel includes: an outlet at the top and an inlet at the bottom;

[0015] When a plurality of bipolar plates are assembled in a battery stack, the outlet and the inlet of the cooling channel of every two adjacent bipolar plates are arranged in opposite positions.

[0016] Furthermore, the membrane electrode assembly in the battery stack includes: a gas diffusion layer; the gas diffusion layer includes: a metal felt layer and carbon paper; the metal felt layer and carbon paper are stacked in sequence between the CCM and the bipolar plate of the membrane electrode assembly; the metal felt layer is arranged on the side close to the CCM and is in contact with the CCM.

[0017] Furthermore, the membrane of the membrane electrode assembly is an anion exchange membrane or a proton exchange membrane.

[0018] The present invention also includes an online performance recovery method for a fuel cell system, comprising the following steps:

[0019] S1. Connect the fuel cell system to the power supply: Start the hydrogen supply system and air supply system, connect the external load, continuously output voltage and current, and gradually increase the current generated by the fuel cell stack generator module through the external load until the current of the fuel cell stack generator module reaches the load current and voltage thresholds; the fuel cell system will continue to operate to provide power to the external load;

[0020] S2. Voltage detection during operation: Every 2 to 10 hours of operation, the fuel cell system checks the voltage of each battery in the stack power generation module through the IGBT control circuit and feeds back the voltage of each battery to the PLC control system in real time. If the difference between the highest and lowest voltages of the battery is ≥100mV, S3 is executed; if the difference between the highest and lowest voltages of the battery is <100mV, the system operates normally.

[0021] S3, performance recovery module operation: open the thermal insulation and heat storage system, control the temperature range to 30 ~ 90 ℃, open the membrane electrode performance recovery module and the bipolar plate performance recovery module.

[0022] Furthermore, in S3, for the membrane electrode, the humidifying unit and the drying unit in the membrane electrode performance recovery module are first turned on, and within a time range of 60 to 200 seconds, humidified gas is introduced into the membrane electrode through the humidifying unit at a frequency of 1 to 10 seconds / pulse interval, and the humidity of the humidified gas is gradually increased in a gradient manner through the ratio control of the humidifying unit and the drying unit; that is, the humidity of the humidified gas is 20 to 50% RH for the first time, and then it is introduced at a frequency of increasing 5 to 10% RH each time.

[0023] Furthermore, in S3, opening the bipolar plate performance recovery module includes the following steps: opening the gas storage unit and the drying unit in the bipolar plate performance recovery module, first introducing gas with a humidity of 0 into the bipolar plate at a flow rate of 200 to 500 mL / min for 60 to 200 seconds; thereafter, opening the acid / alkali solution storage unit, and introducing acid / alkali solution at a pulse interval frequency of 1 to 10 seconds / time and a flow rate of 10 to 100 mL / min for a duration of 60 to 200 seconds.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The present invention makes full use of the coordinated control between the IGBT circuit control system and the PLC system to realize real-time monitoring and automatic adjustment of the performance of the internal components of the fuel cell stack while continuously supplying power. Specifically, through the sensors and data acquisition units in the IGBT circuit, key parameters such as the voltage or current inside the fuel cell stack can be continuously monitored. These data will be fed back to the PLC system and the safety control system in real time to timely evaluate the working status of each component. In this way, the PLC system and the safety control system can monitor whether the performance of the component has declined or whether there is a hidden fault, and then activate the performance recovery function through program control - that is, turn on the membrane electrode and bipolar plate activation protection module to realize the activation treatment of the membrane electrode and bipolar plate; the entire monitoring and control process forms a closed-loop control system, and the monitoring results will be fed back to the PLC control system in real time, and the working parameters will be automatically adjusted according to the actual working status of the components to ensure that the fuel cell stack always operates in the best state; and the coordinated control between the IGBT circuit control system and the PLC system can also predict potential failure modes and issue early warnings based on the accumulation of historical data fed back through program control;

[0026] 2. The fuel cell system of the present invention is equipped with a membrane electrode performance recovery module and a bipolar plate performance recovery module, which can restore the performance of the membrane electrode and bipolar plate online during the operation of the fuel cell system or after long-term storage, thereby improving the overall performance of the high-power fuel cell system; specifically, on the one hand, for the membrane electrode, a gas with a certain humidity is introduced into the interior of the membrane electrode through the rational ratio control of the humidification unit and the drying unit, to purge and infiltrate the three-dimensional resin in the polymer membrane and the catalyst layer, so as to achieve the purpose of improving the performance of the membrane electrode, and the pulsed purge method gives the polymer membrane and the catalyst layer sufficient time and sufficient moisture to sufficiently absorb and fully infiltrate the moisture, and during the activation time, the humidity of the moisture will increase step by step. When the humidity is higher in the later stage, the catalyst layer and polymer membranes such as the proton exchange membrane, alkaline anion exchange membrane, and alkaline membrane can be flushed to improve the conductivity. When the system is started, this purge method can be used to generate water by itself without connecting to an external load or external circuit to complete the humidification measures, and the membrane electrode performance quickly reaches a workable performance;

[0027] For the bipolar plates, first, heated and completely dry (humidity is 0) gas is introduced into the bipolar plates through a gas tank to purge away any residual water in the bipolar plate flow field. Then, by controlling the acid / alkali solution tank in the acid / alkali solution storage unit, acid / alkali solution is introduced into the bipolar plates in a pulsed manner, thereby continuously flushing the passivation layer on the bipolar plate surface, increasing the bipolar plate resistance and thus improving the bipolar plate performance.

[0028] In addition, the present invention has designed a heat preservation and heat storage system for both the membrane electrode and bipolar plate performance recovery modules to improve the system's thermal management capabilities. In particular, during the performance recovery process, on the one hand, the heated gas facilitates the rapid purge of residual water in the bipolar plates. On the other hand, without the heat preservation and heat storage system, the pulsed addition of large amounts of moisture and acid / alkaline solutions during the operation of the fuel cell stack can easily cause thermal shocks to the membrane and the interior of the fuel cell stack, causing the catalyst layer to peel off and affecting the fuel cell system.

[0029] 3. The IGBT control circuit in this stack system can also automatically help restore the performance of the membrane electrode and bipolar plate by adjusting the output of the IGBT and regulating the charging current; for example, by applying a certain current, small current electrolysis produces water, promotes the regeneration of reactants, improves the wetness of the membrane electrode, and thus improves the power generation capacity of the membrane electrode.

[0030] 4. Regular cleaning and activation: The coordinated control of the IGBT system and the PLC system can also start the gas and liquid purge process on a regular basis as needed to clean and activate the membrane electrode and bipolar plate in the stack system, expel impurities deposited on the surface, and restore their conductivity and reaction efficiency.

[0031] 5. In summary, the present invention can utilize the life extension control strategy proposed by the coordinated control of the IGBT circuit and the PLC system to monitor the performance of the components inside the stack in real time while continuously supplying power, and has the function of recovering the performance of the components, thereby reducing the long-term unhealthy external output of the fuel cell stack system, thereby extending the service life of the fuel cell stack system.

[0032] 6. The system of the present invention also integrates an air filter, a temperature sensor and an electronic radiator to increase the gas purity and temperature control capabilities, thereby improving the output performance of the fuel cell stack per unit area and enhancing the overall operating efficiency;

[0033] 7. When the bipolar plates used in the present invention are cooled by coolant, the cooling channels of two adjacent components flow in opposite directions, so that the heat absorption degree of the inlet and outlet temperatures of each cooling channel is basically equal. This can enhance the cooling effect and uniformity between the bipolar plates and the membrane electrode, thereby effectively maintaining the temperature balance inside the fuel cell stack and enhancing mass transfer. In addition, in the online activation process of the bipolar plates, this design can improve the purge efficiency, facilitate rapid heat transfer, and thus achieve rapid activation, thereby quickly improving the performance and stability of the fuel cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 Schematic diagram of system connections of the fuel cell system of the present invention.

[0036] Figure 2 Schematic diagram of the structure of the cooling channel in the bipolar plate of the present invention.

[0037] Figure 3 This is a schematic diagram of the positions of the water inlet and outlet of the cooling channel after the bipolar plate of the present invention is installed in the fuel cell stack.

[0038] In the figure: 1. cathode plate; 2. anode plate; 3. cooling channel; 4. cathode flow field channel; 5. anode flow field channel; 6. water inlet; 7. water outlet; 8. bipolar plate assembly; 9. membrane electrode assembly. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] like Figure 1-3 As shown, the present invention provides a fuel cell system, comprising: a stack power generation module, an external load, a PLC control system, a hydrogen supply system, and an oxygen supply system. The stack power generation module is formed by connecting multiple stack bodies in parallel. The fuel cell system also includes a membrane electrode performance recovery module, a bipolar plate performance recovery module, and an IGBT control circuit, which are connected to the stack power generation module circuit signal. The membrane electrode performance recovery module and the bipolar plate performance recovery module are both connected to the thermal insulation and heat storage module circuit and then to the PLC system circuit signal. The IGBT control circuit is connected to the PLC system circuit signal. The membrane electrode performance recovery module includes a drying unit and a humidifying unit. The bipolar plate performance recovery module includes an acid / alkali solution storage unit, a drying unit, and a gas storage unit. The acid / alkali solution storage unit and the gas storage unit are each separately connected to the stack module piping and circuit.

[0042] As a preferred embodiment, the heat preservation and heat storage module includes a heat preservation air pump, a battery and a heating wire.

[0043] As a preferred embodiment, in the present application, the gas storage unit includes a gas storage tank, a pressure gauge, a flow meter, and a hygrometer; the acid / alkali solution storage unit includes an acid / alkali solution tank, a pressure gauge, and a flow meter; the drying unit includes a limestone filtering mechanism, and the limestone filtering mechanism mainly includes a filter tank containing limestone raw materials. By controlling parameters such as the time and flow rate of the gas entering the limestone raw material filter tank, the humidity of the gas after passing through the filter tank can be better controlled; the humidification unit includes a humidifier, a pressure gauge, a flow meter, and a hygrometer.

[0044] In the present application, preferably, the fuel cell power generation module is also connected to the air filter, temperature sensor, and electronic radiator circuit; the air filter, temperature sensor, electronic radiator, hydrogen supply system, and air supply system are all connected to the PLC control system to realize the circuit controlled by the PLC control system.

[0045] Preferably, in the present application, the battery stack is composed of a plurality of bipolar plate assemblies and a plurality of membrane electrode assemblies that are staggered and stacked with each other; a cooling channel is provided between the anode plate and the cathode plate of the bipolar plate assembly; the cooling channel includes: an outlet at the top and an inlet at the bottom; when the bipolar plate assembly is assembled in the battery stack, the outlet and inlet of the cooling channel of each adjacent two bipolar plate assemblies are arranged in opposite positions.

[0046] As a preferred embodiment, the membrane electrode assembly in the battery stack includes: a gas diffusion layer; the gas diffusion layer includes: a metal felt layer and carbon paper; the metal felt layer and the carbon paper are stacked in sequence between the CCM and the bipolar plate of the membrane electrode assembly; the metal felt layer is arranged on the side close to the CCM and is in contact with the CCM.

[0047] In this application, the gas flow rate in the gas storage tank storage unit is 0-800 mL / min, the humidity is 0-100 wt%, and the pressure is 0-0.1 MPa. The gas in the gas storage tank is a mixture of one or more of oxygen, hydrogen, nitrogen, and air. The acid / alkali solution flow rate in the acid / alkali solution storage unit is 0-500 mL / min, and the liquid is an aqueous solution of either H+ or OH- at a concentration of 0-7 mol / l.

[0048] As a preferred embodiment, the membrane of the membrane electrode in the membrane electrode performance recovery module is an anion exchange membrane or a proton exchange membrane.

[0049] The present invention also includes an online performance recovery method for a fuel cell system, comprising the following steps:

[0050] S1. Connecting the fuel cell system to power: Start the hydrogen supply system and the air supply system, connect the external load, continuously output voltage and current, and gradually increase the current generated by the stack power generation module through the external load (in this application, this can be done by adjusting the current, voltage, or load resistance, as long as the current generated by the stack power generation module can be increased) until the current of the stack power generation module reaches the load current and voltage thresholds; the fuel cell system will continue to operate to provide power to the external load;

[0051] S2. Voltage detection during operation: Every 2 to 10 hours of operation of the fuel cell system, the voltage of each cell (each membrane electrode) in the stack power generation module is checked through the IGBT control circuit, and the voltage of each cell is fed back to the PLC control system in real time; if the difference between the highest and lowest voltages of the battery is ≥100mV, the performance recovery module is turned on and S3 is executed; if the difference between the highest and lowest voltages of the battery is <100mV, the system operates normally;

[0052] S3, the performance recovery module works: turn on the heat preservation and heat storage system (the heat storage system mentioned here is a commonly used device in this field. Specifically, the battery is powered on, and the heating wire is heated to make the air pump continuously output hot gas to achieve heating of the object), control the temperature range to 30-90°C, turn on the membrane electrode performance recovery module and the bipolar plate performance recovery module, and purge the acid / alkali solution or gas into the membrane electrode and the bipolar plate for a duration of 60-200S. For the membrane electrode, first turn on the humidifying unit and the drying unit in the membrane electrode performance recovery module, and within the time range of 60-200s, humidified gas is introduced into the membrane electrode through the humidifying unit at a frequency of 1-10S / pulse interval, and the humidity of the humidified gas is gradually increased in a gradient manner through the ratio control of the humidifying unit and the drying unit: that is, the humidity of the humidified gas is 20-50%RH for the first time, and then it is introduced at a frequency of increasing 5-10%RH each time. For the bipolar plate, the gas storage unit and the drying unit in the bipolar plate performance recovery module are first opened, and completely dry gas (humidity is 0) is first introduced into the bipolar plate at a flow rate of 200 to 500 mL / min for 60 to 200 seconds; then, the acid / alkali solution storage unit is opened, and the acid / alkali solution is introduced at a pulse interval frequency of 1 to 10 seconds / time and a flow rate of 10 to 100 mL / min for a duration of 60 to 200 seconds.

[0053] Example 1

[0054] A fuel cell system, such as Figure 1 As shown, it includes: a stack power generation module, an external load, a PLC control system, a hydrogen supply system and an oxygen supply system. The stack power generation module is formed by multiple stack bodies connected in parallel. The fuel cell system also includes a membrane electrode performance recovery module, a bipolar plate performance recovery module and an IGBT control circuit connected to the circuit signal of the stack power generation module. The membrane electrode performance recovery module and the bipolar plate performance recovery module are both connected to the insulation and heat storage module circuit and then connected to the PLC system circuit signal. The IGBT control circuit is connected to the PLC system circuit signal. The insulation and heat storage system uses insulation air pumps, batteries, heating wires and other main components.

[0055] The membrane electrode performance recovery module includes a drying unit and a humidifying unit. The bipolar plate performance recovery module includes an acid / alkali solution storage unit, a drying unit, and a gas storage unit. Both the acid / alkali solution storage unit and the gas storage unit are independently connected to the stack module piping and circuitry. The gas storage unit includes a gas storage tank, a pressure gauge, a flow meter, and a hygrometer, while the acid / alkali solution storage unit includes an acid / alkali solution tank, a pressure gauge, and a flow meter. The drying unit includes a limestone filter mechanism, and the humidifying unit includes a humidifier, a pressure gauge, a flow meter, and a hygrometer.

[0056] The flow rate in the acidic / alkaline solution tank is 0-500mL / min, and the liquid is an aqueous solution of one of H+ and OH- with a concentration of 0-7mol / l; the catalytic layer protection module includes a gas storage tank whose flow, humidity, and pressure are controlled by an IGBT control circuit, as well as a flow meter, a hygrometer, a pressure gauge, etc. The gas flow rate in the gas storage tank is 0-800mL / min. In this embodiment, the humidity is 0-100RH%, the pressure is 0-0.1MPa, and the gas type is one or more of oxygen, hydrogen, nitrogen, and air.

[0057] Furthermore, in the fuel cell system of the present invention, the stack power generation module is also connected to the air filter, the temperature sensor, and the electronic radiator circuit, and the hydrogen inlet and the air inlet of the stack power generation module are connected to the hydrogen supply system and the air supply system respectively;

[0058] Furthermore, the air filter, temperature sensor, electronic radiator, hydrogen supply system and air supply system are all connected to the PLC control system circuit to form a circuit controlled by the PLC control system.

[0059] Example 2

[0060] like Figure 2 As shown, the battery stack is composed of a plurality of bipolar plate assemblies and a plurality of membrane electrode assemblies that are staggered and stacked with each other; a cooling channel is provided between the anode plate and the cathode plate of the bipolar plate assembly 8; the flow field structure of the anode plate and the cathode plate of the bipolar plate is generally formed by stamping, thereby realizing a flow field structure consisting of flow channel ridges and flow channel grooves. When the non-flow field structure side of the anode plate 2 and the cathode plate 1 are overlapped and fixed, the grooves corresponding to the flow field ridges on the side of the non-flow field structure between the two plates are spliced ​​together to form the cooling channel. The cooling channel includes an outlet at the top and an inlet at the bottom. In this embodiment, when the bipolar plate assembly 8 is assembled in the battery stack, the water outlet 7 and the water inlet 6 of each two adjacent bipolar plate assemblies 8 are arranged in opposite positions, as shown in FIG. Figure 3 shown.

[0061] The membrane electrode assembly (MEA) in the stack consists of a gas diffusion layer (GDL), which includes a metal felt layer and carbon paper. The metal felt layer and carbon paper are stacked in sequence between the CCM and bipolar plate of the MEA. The metal felt layer is positioned on the side closest to the CCM and adheres to it. The MEA in the MERM is an anion exchange membrane or a proton exchange membrane.

[0062] The present invention further discloses a method for recovering the performance of the above fuel cell system:

[0063] S1. Connect the fuel cell system to the power supply: start the hydrogen supply system and air supply system, connect the external load, and continuously output voltage and current. The external load gradually increases the current generated by the fuel cell power generation module, that is, 0-1000mA / cm2 In this embodiment, the current density can be increased by 50mA / cm every 10 minutes. 2 The current density is not more than 1000mA / cm 2 , until the current of the fuel cell power generation module reaches the threshold of the load current and voltage, then the fuel cell system will continue to operate to provide power to the external load;

[0064] S2. Voltage detection during operation: Every three hours of operation, the fuel cell system checks the voltage of each cell in the stack power generation module through the IGBT control circuit and feeds back the voltage of each cell to the PLC control system in real time. In this embodiment, if the difference between the highest and lowest voltages of the cells in the circuit is 130mV, or ≥100mV, it indicates a performance degradation problem. In this case, the performance recovery module is activated and S3 is executed.

[0065] S3, membrane electrode performance recovery module: turn on the thermal insulation and heat storage system, control the temperature range to 60 ° C, turn on the membrane electrode performance recovery module and the bipolar plate performance recovery module. For the membrane electrode, first turn on the humidification unit and the drying unit in the membrane electrode performance recovery module, and switch the pipeline of the humidification unit through the valve control. Under the action of the limestone filtration mechanism, the humidification unit allows 30% RH humidified gas to be introduced into the membrane electrode. After that, within a time range of 100 s and at a pulse interval frequency of 6 s / time, the humidity of the humidified gas is gradually increased in a gradient manner, and the humidity is increased by 8% RH each time. For the bipolar plates, first open the gas storage unit in the bipolar plate performance recovery module, that is, after the gas tank circulates in the drying unit, make the gas completely dry (humidity is 0), and pass it into the bipolar plates of the stack module at a flow rate of 300mL / min for 100s; then, close the gas storage unit, open the acid / alkali solution storage unit, and within the duration of 100s, pass the acid / alkali solution into the bipolar plates at a frequency of 8S pulse interval and a flow rate of 60mL / min.

[0066] S4: The IGBT control circuit checks the voltage of each battery in the stack power generation module and feeds back the voltage of each battery to the PLC control system in real time. At this time, the difference between the highest and lowest voltages of the batteries in the circuit is 105mV, which is ≥100mV, indicating that a performance problem has not been completely resolved. At this time, the performance recovery module works again (repeating S3);

[0067] S5. The IGBT control circuit checks the voltage of each battery in the stack power generation module and feeds back the voltage of each battery to the PLC control system in real time. At this time, the difference between the highest and lowest voltages of the battery in the circuit is 88mV, which is less than 100mv. This means that the activation of the bipolar plate and membrane electrode has been completed, the hidden danger has been eliminated, and the fuel cell system is working normally.

[0068] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0069] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. In actual implementation, there can be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fuel cell system comprising: The stack power generation module, external load, PLC control system, hydrogen supply system and oxygen supply system are characterized in that: the stack power generation module is formed by multiple stack bodies connected in parallel; The fuel cell system also includes a membrane electrode performance recovery module, a bipolar plate performance recovery module, and an IGBT control circuit that are connected to the stack power generation module circuit signal. The membrane electrode performance recovery module and the bipolar plate performance recovery module are both connected to the heat preservation and heat storage module circuit and then connected to the PLC system circuit signal. The IGBT control circuit is connected to the PLC system circuit signal. The membrane electrode performance recovery module is equipped with a drying unit and a humidifying unit; the bipolar plate performance recovery module includes an acid / alkali solution storage unit, a drying unit, and a gas storage unit; the acid / alkali solution storage unit and the gas storage unit are each separately connected to the stack module pipeline and circuit; The heat preservation and heat storage module heats the gas and liquid in the membrane electrode performance recovery module and the bipolar plate performance recovery module; The stack power generation module is also connected to the air filter, temperature sensor, and electronic radiator circuit; the air filter, temperature sensor, electronic radiator, hydrogen supply system, and air supply system are all connected to the PLC control system to realize the circuit being controlled by the PLC control system.

2. A fuel cell system according to claim 1, characterized in that: The gas storage unit includes a gas storage tank, a pressure gauge, a flow meter, and a hygrometer; the acid / alkali solution storage unit includes an acid / alkali solution tank, a pressure gauge, and a flow meter; the drying unit includes a limestone filtering mechanism; and the humidification unit includes a humidifier, a pressure gauge, a flow meter, and a hygrometer.

3. The fuel cell system according to claim 1, wherein: The heat preservation and heat storage module includes a heat preservation air pump, a storage battery and a heating wire.

4. The fuel cell system according to claim 1, wherein: A cooling channel is provided between the anode plate and the cathode plate of the bipolar plate of the battery stack; the cooling channel includes: an outlet at the top and an inlet at the bottom; When a plurality of bipolar plates are assembled in a battery stack, the outlet and the inlet of the cooling channel of every two adjacent bipolar plates are arranged in opposite positions.

5. A fuel cell system according to claim 4, characterized in that: The membrane electrode assembly in the battery stack includes: a gas diffusion layer; the gas diffusion layer includes: a metal felt layer and carbon paper; the metal felt layer and carbon paper are stacked in sequence between the CCM and the bipolar plate of the membrane electrode assembly; the metal felt layer is arranged on the side close to the CCM and is in contact with the CCM.

6. A fuel cell system according to claim 4 or 5, characterized in that: The membrane of the membrane electrode assembly is an anion exchange membrane or a proton exchange membrane.

7. A method for online performance recovery of a fuel cell system, applying the system according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Connect the fuel cell system to the power supply: Start the hydrogen supply system and air supply system, connect the external load, continuously output voltage and current, and gradually increase the current generated by the fuel cell stack generator module through the external load until the current of the fuel cell stack generator module reaches the load current and voltage thresholds; the fuel cell system will continue to operate to provide power to the external load; S2. Voltage detection during operation: Every 2 to 10 hours of operation, the fuel cell system checks the voltage of each battery in the stack power generation module through the IGBT control circuit and feeds back the voltage of each battery to the PLC control system in real time. If the difference between the highest and lowest voltages of the battery is ≥100mV, S3 is executed; if the difference between the highest and lowest voltages of the battery is <100mV, the system operates normally. S3, performance recovery module operation: open the thermal insulation and heat storage system, control the temperature range to 30 ~ 90 ℃, open the membrane electrode performance recovery module and the bipolar plate performance recovery module.

8. The online performance recovery method of a fuel cell system according to claim 7, characterized in that: In S3, for the membrane electrode performance recovery module: the humidifying unit and the drying unit in the membrane electrode performance recovery module are turned on, and within a time range of 60 to 200 seconds, humidified gas is introduced into the membrane electrode through the humidifying unit at a frequency of 1 to 10 seconds per pulse interval, and the humidity of the gas is controlled by the humidifying unit and the drying unit.

9. The method for online performance recovery of a fuel cell system according to claim 7, wherein: In S3, opening the bipolar plate performance recovery module includes the following steps: first, opening the gas storage unit and the drying unit in the bipolar plate performance recovery module, and introducing gas with a humidity of 0 into the bipolar plate at a flow rate of 200-500 mL / min for 60-200 seconds; then, opening the acid / alkali solution storage unit, and introducing acid / alkali solution at a pulse interval frequency of 1-10 seconds / time and a flow rate of 10-100 mL / min for a duration of 60-200 seconds.

10. The online performance recovery method of a fuel cell system according to claim 8, characterized in that: The specific method of controlling the gas humidity is as follows: the humidity of the humidified gas is initially set at 20-50% RH, and then the humidity is increased by 5-10% RH each time.

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