Fuel cell system and online performance recovery method

Abstract

The invention 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 galvanic pile power generation module, an external load, a PLC (Programmable Logic Controller) 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 (Insulated Gate Bipolar Transistor) control circuit which are in circuit signal connection with the galvanic pile power generation module, the membrane electrode performance recovery module and the bipolar plate performance recovery module are both in circuit connection with the heat preservation and storage module and then are in circuit signal connection with the PLC system, and the IGBT control circuit is in circuit signal connection with the PLC system. According to the invention, cooperative control between the IGBT circuit control system and the PLC system is fully utilized, real-time monitoring and automatic adjustment of the performance of the internal parts of the stack are realized while continuous power supply is realized, and when the IGBT control circuit and the PLC monitor that the performance is reduced, real-time online activation can be realized through the membrane electrode performance recovery module and the bipolar plate performance recovery module, so that the reliability of the stack is improved. And the performance is quickly recovered.

Description

Technical Field

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

[0002] Fuel cells, as an environmentally friendly, efficient and long-life power generation device, play an important role in the energy field. Taking the proton exchange membrane fuel cell (PEMFC) as an example, its working principle is: the reaction gas enters from the anode side, the hydrogen atoms lose electrons at the anode and turn into protons, the protons pass through the proton exchange membrane to the cathode, and the electrons reach the cathode through the external loop and combine with oxygen to generate water. Compared with traditional power generation methods, fuel cells convert chemical energy into electrical energy in a non-combustion way, and the direct power generation efficiency can be as high as 45%, which is not limited by the Carnot cycle. The system with the fuel cell stack as the core integrates power management, thermal management and other modules, and has the characteristics of coordinated management of heat, electricity, water and gas. Fuel cell system products are widely used, from fixed power stations to mobile power sources, from electric vehicles to spacecraft, from military equipment to civilian products, and have a wide range of applications.

[0003] Fuel cell fuel cell system usually consists of fuel cell stack and BOP auxiliary system. After hydrogen and air are introduced into the system, electricity is generated and supplied to external load and external circuit. 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, so it occupies a key position in fuel cell production. Usually, the fuel cell system will carry out other activation steps in a targeted manner, such as proton exchange membrane humidification, material transfer channel establishment, electrode structure optimization and catalyst layer activity improvement, so that the stack can reach the best performance state. In 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-, CO32-, the number of anions is reduced, and the conductivity is reduced, which further affects the performance and life of the fuel cell system. Traditional online activation methods such as constant current and variable current forced activation - adjusting the current or voltage by connecting an external load or forcibly pulling a load to achieve rapid activation. This process lacks an effective control mechanism and lacks control and detection of the internal membrane, membrane electrode, and bipolar plate of the stack. This leads to unstable current and voltage in the system at the beginning of load connection and the moment of forced loading. The load current fluctuates greatly and causes local overheating of the bipolar plate. At this time, the components inside 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 reaction speed and stability of the system and extend its service life. Summary of the invention

[0004] According 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 by 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 a plurality of stack bodies connected in parallel, the fuel cell system further comprises a membrane electrode performance recovery module, a bipolar plate performance recovery module and an IGBT control circuit, 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, 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 has 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 realizes heating of gas and liquid in the membrane electrode performance recovery module and the bipolar plate performance recovery module.

[0010] Further, 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; the humidification unit includes a humidifier, a pressure gauge, a flow meter, and a hygrometer;

[0011] Furthermore, the battery 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 a circuit that is controlled by the PLC control system;

[0013] The heat preservation and heat storage module comprises 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 comprises: 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 a 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. Power connection of the fuel cell system: start the hydrogen supply system and the air supply system, connect the external load, continuously output voltage and current to the outside, and gradually increase the current generated by the stack power generation module through the external load until the current of the stack power generation module reaches the threshold of the load current and voltage; the fuel cell system will continue to operate to provide power to the external load;

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

[0021] S3, performance recovery module operation: turn on the thermal insulation and heat storage system, control the temperature range to 30-90°C, turn on 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 a gas with a humidity of 0 into the bipolar plate at a flow rate of 200 to 500 mL / min for 60 to 200 s; thereafter, opening the acid / alkali solution storage unit, and introducing an acid / alkali solution at a pulse interval frequency of 1 to 10 S / time and a flow rate of 10 to 100 mL / min for a duration of 60 to 200 s.

[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 battery 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 battery 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, so that the PLC system and the safety control system can monitor whether the performance of the component has declined or whether there is a hidden danger of failure, and then activate the performance recovery function through program control - that is, turn on the membrane electrode and bipolar plate activation protection module to achieve 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 battery stack always works 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 through program control for the accumulation of historical data fed back;

[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 the 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, the gas with a certain humidity is passed into the membrane electrode through the rational proportion control of the humidification unit and the drying unit, and the three-dimensional resin in the polymer membrane and the catalyst layer is purged and infiltrated to achieve the purpose of improving the performance of the membrane electrode. The pulse purging method gives the polymer membrane and the catalyst layer enough 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 high in the later stage, the catalyst layer and the polymer membranes such as the proton exchange membrane, the alkaline anion exchange membrane, and the alkaline membrane can be flushed to improve the conductivity. When the system is started, the purging method can be used to generate water by itself without connecting to an external load or an external circuit to complete the humidification measures, and the membrane electrode performance quickly reaches a workable performance;

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

[0028] In addition, the present invention designs a heat preservation and heat storage system for both the membrane electrode and bipolar plate performance recovery modules to improve the thermal management capability of the system, especially during the performance recovery process. On the one hand, the warm gas is conducive to quickly purging the residual water in the bipolar plate. On the other hand, if there is no heat preservation and heat storage system, during the operation of the fuel cell stack, the pulsed addition of large moisture and acid / alkaline solution can easily cause thermal shock to the membrane and the inside of the fuel cell stack, causing the catalyst layer to peel off, affecting the fuel cell system.

[0029] 3. The IGBT control circuit in the stack system can also automatically help restore the performance of the membrane electrode and bipolar plate by adjusting the output of the IGBT and adjusting the charging current; for example, by applying a certain current, a small current electrolysis produces water, which promotes the regeneration of reactants, improves the wetness of the membrane electrode, and thereby 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 its 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, and thus 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 battery stack per unit area and enhancing the overall operating efficiency;

[0033] 7. When the bipolar plate used in the present invention is cooled by coolant, the cooling channels of two adjacent components flow in opposite directions, so that the inlet and outlet temperatures of each cooling channel have basically the same degree of heat absorption. This can enhance the cooling effect and uniformity between the bipolar plate 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 plate, this design can improve the purge efficiency, which is conducive to rapid heat transfer, thereby achieving rapid activation, thereby rapidly 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.

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

[0036] Figure 2 It is a schematic diagram of the structure of the cooling channel in the bipolar plate of the present invention.

[0037] Figure 3 The figure 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 battery 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 scheme of the present invention, the technical scheme 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 described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first", "second", etc. in the specification 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 data 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 that are 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, including: 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, and 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 stack power generation module circuit signal. The membrane electrode performance recovery module and the bipolar plate performance recovery module are connected to the 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; 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; the acid / alkali solution storage unit and the gas storage unit are separately connected to the stack module pipeline and circuit.

[0042] As a preferred embodiment, the heat preservation and thermal 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 comprises: 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 two adjacent 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 a side close to the CCM and is in contact with the CCM.

[0047] In the present application, the gas flow rate in the gas storage tank storage unit is 0-800mL / min, the humidity is 0-100wt%, and the pressure is 0-0.1MPa; the type of 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 tank of the acid / alkali solution storage unit is 0-500mL / min, and the liquid is an aqueous solution of one of H+ and OH- at 0-7mol / 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. Power-on operation of the fuel cell system: start the hydrogen supply system and the air supply system, connect the external load, continuously output voltage and current to the outside, and gradually increase the current generated by the stack power generation module through the external load (in this application, it can be 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 threshold of the load current and voltage; 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 battery (each membrane electrode) in the stack power generation module is checked through the IGBT control circuit, and the voltage of each battery 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, the electric heating wire is heated to make the air pump continuously output hot air 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 humidification unit and the drying unit in the membrane electrode performance recovery module, and within the time range of 60-200s, the humidification gas is introduced into the membrane electrode through the humidification unit at a frequency of 1-10S / pulse interval, and the humidity of the humidification gas is gradually increased by the proportional control of the humidification 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 10S / 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 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 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 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 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 individually connected to the pipelines and circuits of the stack module. 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 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] 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 one side of the non-flow field structure of the anode plate 2 and the cathode plate 1 is overlapped and fixed, the grooves corresponding to the flow field ridges on one 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 the present 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, such as Figure 3 shown.

[0061] 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 fits with the CCM. The membrane of the membrane electrode in the membrane electrode performance recovery module is an anion exchange membrane or a proton exchange membrane.

[0062] The present invention further discloses a performance recovery method 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, continuously output voltage and current to the outside, and 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 50 mA / cm every 10 minutes. 2 The current density is not more than 1000mA / cm 2 , until the current of the power generation module of the fuel cell stack reaches the threshold of the load current and voltage, after which the fuel cell system will continue to operate to provide power to the external load;

[0064] S2. Voltage detection during operation: The fuel cell system checks the voltage of each battery in the stack power generation module through the IGBT control circuit every 3 hours, and feeds back the voltage of each battery to the PLC control system in real time; in this embodiment, the difference between the highest voltage and the lowest voltage of the battery in the circuit is 130mV, which is ≥100mV, indicating that there is a performance degradation problem. At this time, the performance recovery module is turned on 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 valve control, so that the humidification unit, under the action of the limestone filtration mechanism, introduces 30% RH humidified gas into the membrane electrode, and then, within a time range of 100s and at a pulse interval frequency of 6S / time, gradually increase the humidity of the humidified gas in a gradient manner, and each increase in humidity is 8% RH. 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 battery 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 voltage and the lowest voltage of the battery in the circuit is 105mV, which is ≥100mV, indicating that there is a performance problem that has not been completely solved. At this time, the performance recovery module works again (repeat S3);

[0067] S5, 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 voltage and the lowest voltage of the battery in the circuit is 88mV, which is less than 100mv, indicating that the activation of the bipolar plate and the 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 only for description and do not represent the advantages or disadvantages of the embodiments.

[0069] In the above-mentioned 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. There may be other division methods in actual implementation, 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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: A fuel cell power generation module, an external load, a PLC control system, a hydrogen supply system and an oxygen supply system, wherein the fuel cell power generation module is formed by connecting a plurality of fuel cell 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. The membrane electrode performance recovery module and the bipolar plate performance recovery module are 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 connected to the stack power generation module circuit signal; the bipolar plate performance recovery module is connected to the stack power generation module circuit signal; The membrane electrode performance recovery module has 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 heat preservation and heat storage module realizes heating of gas and liquid in the membrane electrode performance recovery module and the bipolar plate performance recovery module.

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. A fuel cell system according to claim 1, characterized in that: The stack power generation module is also connected to an air filter, a temperature sensor, and an 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 a circuit that is controlled by the PLC control system; The heat preservation and heat storage module comprises a heat preservation air pump, a storage battery and a heating wire.

4. A fuel cell system according to claim 1, characterized in that: A cooling channel is provided between the anode plate and the cathode plate of the bipolar plate of the battery stack; the cooling channel comprises: 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 a 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, using the system according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Power connection of the fuel cell system: start the hydrogen supply system and the air supply system, connect the external load, continuously output voltage and current to the outside, and gradually increase the current generated by the stack power generation module through the external load until the current of the stack power generation module reaches the threshold of the load current and voltage; the fuel cell system will continue to operate to provide power to the external load; S2. Voltage detection during operation: The fuel cell system checks the voltage of each battery in the stack power generation module through the IGBT control circuit every 2 to 10 hours of operation, 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, execute S3; if the difference between the highest and lowest voltages of the battery is <100mV, the system operates normally; S3, performance recovery module operation: turn on the thermal insulation and heat storage system, control the temperature range to 30-90°C, turn on the membrane electrode performance recovery module and the bipolar plate performance recovery module.

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

9. The method for online performance recovery of a fuel cell system according to claim 7, characterized in that: 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 passing 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; then, opening the acid / alkali solution storage unit, and passing acid / alkali solution at a pulse interval frequency of 1 to 10S / time and a flow rate of 10 to 100 mL / min for a duration of 60 to 200 seconds.

10. The method for online performance recovery of a fuel cell system according to claim 8, characterized in that: The control of the gas humidity is specifically as follows: the humidity of the first humidified gas is 20-50% RH, and then the gas is introduced at a frequency of increasing 5-10% RH each time.

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