A hydrogen fuel cell module for controlling the pressure difference between the anode and cathode

Abstract

The subject matter herein can be embodied in, inter alia, a hydrogen fuel cell anode control system including a hydrogen inlet configured to receive pressurized hydrogen, a hydrogen outlet configured to fluidly couple to an anode manifold of a hydrogen fuel cell, a recirculation inlet configured to receive hydrogen overflow from the anode manifold, a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet, a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet, a differential pressure measurement module configured to measure a differential pressure between the anode manifold and cathode manifold of the hydrogen fuel cell, and a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure.

Description

[Technical field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 262,798, filed October 20, 2021, and U.S. Patent Application No. 18 / 047,976, filed October 19, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to hydrogen fuel cells. [Background technology]

[0003] Hydrogen fuel cells are devices configured to consume hydrogen and oxygen in a catalytic electrochemical process to produce electricity as the primary product and water and heat as exhaust. The appeal of such devices is obvious, but their realization has been hindered by their highly customized and application-specific construction, their high cost due to the lack of a mass production platform, the lack of a fuel infrastructure, and the lack of robustness and durability of conventional controls. Improved control can improve efficiency and power output, as well as robustness and durability, thereby enhancing the proposition of fuel cell systems. Summary of the Invention

[0004] Generally, this specification describes systems and techniques for controlling hydrogen supply in a hydrogen fuel cell.

[0005] In a first embodiment, a hydrogen fuel cell anode control system includes a hydrogen inlet configured to receive pressurized hydrogen, a hydrogen outlet configured to fluidly couple to an anode manifold of a hydrogen fuel cell, a recirculation inlet configured to receive hydrogen overflow from the anode manifold, a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet, a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet, a differential pressure measurement module configured to measure a differential pressure between the anode manifold and cathode manifold of the hydrogen fuel cell, and a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure.

[0006] In a second embodiment according to the first embodiment, the controller is configured to control the hydrogen pressure so that the differential pressure is approximately zero.

[0007] In a third embodiment according to the first or second embodiment, the hydrogen pressure regulator is a controllable gas pressure regulator system.

[0008] In a fourth embodiment related to any one of the first to third embodiments, the hydrogen recirculation module includes a gas recirculation pump.

[0009] In a fifth embodiment related to any one of the first to fourth embodiments, the hydrogen recirculation module includes a jet pump.

[0010] In a sixth embodiment relating to any one of embodiments 1 to 5, the system further includes a current feedback input port configured to receive a current measurement value based on the output power of the fuel cell, and the controller is further configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the current measurement value.

[0011] In a seventh embodiment related to any one of the first to sixth embodiments, the system further includes a current feedback input port configured to receive a current measurement based on an input power of a compressor configured to supply oxygen to the cathode manifold, and the controller is further configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the current measurement.

[0012] In an eighth embodiment related to any one of the first to seventh embodiments, the controller is configured to control the hydrogen pressure based on a predetermined control model.

[0013] In a ninth embodiment related to any one of the first to eighth embodiments, the system further comprises a humidity controller configured to control a humidity level of the hydrogen mixture.

[0014] In a tenth embodiment related to any one of the first to ninth embodiments, the system further comprises a nitrogen separator configured to reduce at least one nitrogen level in the overflow hydrogen or hydrogen mixture.

[0015] In an eleventh embodiment related to any one of the first to tenth embodiments, the controller is further configured to control a variable pressure control valve configured to control a pressure of the overflowed hydrogen.

[0016] In a twelfth embodiment, a method of controlling anode manifold pressure in a hydrogen fuel cell includes measuring an anode manifold pressure, measuring a cathode manifold pressure, determining a differential pressure value based on the measured anode manifold pressure and the measured cathode manifold pressure, and controlling at least one of a hydrogen pressure regulator, a hydrogen recirculation module, or an anode outlet valve based on the determined differential pressure.

[0017] In a thirteenth embodiment related to the twelfth embodiment, the method further includes receiving pressurized hydrogen; regulating the received pressurized hydrogen to a regulated pressure by a hydrogen pressure regulator; receiving overflow hydrogen from the anode manifold; and mixing the pressurized hydrogen received from the hydrogen pressure regulator with the received overflow hydrogen by a hydrogen recirculation module to provide a hydrogen mixture to a hydrogen outlet.

[0018] In a fourteenth embodiment related to embodiments 12 or 13, controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the determined differential pressure further includes controlling the anode manifold pressure so that the differential pressure is approximately zero.

[0019] In a fifteenth embodiment relating to any one of embodiments 12 to 14, the method further includes receiving a current measurement based on the output power of the hydrogen fuel cell, and controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the received current measurement.

[0020] In a sixteenth embodiment related to any one of embodiments 12 to 15, the method further includes receiving a current measurement based on a power consumption of a compressor configured to supply oxygen to the cathode manifold, and controlling at least one of a hydrogen pressure regulator or a hydrogen recirculation module based on the received current measurement.

[0021] In a seventeenth embodiment related to any one of embodiments 12 to 16, the method further includes controlling, by the controller, the humidity control module to controllably add or remove humidity from the hydrogen mixture based on a predetermined humidity level.

[0022] In an eighteenth embodiment related to any one of embodiments 12 to 17, the method further includes a nitrogen separator module configured to reduce at least one nitrogen level in the overflow hydrogen or hydrogen mixture.

[0023] In a 19th embodiment related to any one of embodiments 12 to 18, the method further includes controlling the pressure of the overflowed hydrogen with a variable pressure control valve.

[0024] In a twentieth embodiment, a hydrogen fuel cell assembly includes a hydrogen fuel cell including an anode manifold, a stack, and a cathode manifold, and a hydrogen fuel cell anode control system including a hydrogen inlet configured to receive pressurized hydrogen, a hydrogen outlet configured to fluidly couple to the anode manifold of the hydrogen fuel cell, a recirculation inlet configured to receive overflow hydrogen from the anode manifold, a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet, a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet, a differential pressure measurement module configured to measure a differential pressure between the anode manifold and cathode manifold of the hydrogen fuel cell, and a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure.

[0025] In an exemplary embodiment, a hydrogen fuel cell anode control system includes a hydrogen inlet configured to receive pressurized hydrogen, a hydrogen outlet configured to fluidly couple to an anode manifold of a hydrogen fuel cell, a recirculation inlet configured to receive hydrogen overflow from the anode manifold, a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet, a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet, a differential pressure measurement module configured to measure a differential pressure between the anode manifold and cathode manifold of the hydrogen fuel cell, and a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure.

[0026] Various embodiments may include some, all, or none of the following features: The controller may be configured to control the hydrogen pressure such that the differential pressure is approximately zero. The hydrogen pressure regulator may be a controllable gas pressure regulator system. The hydrogen recirculation module may include a gas recirculation pump. The hydrogen recirculation module may include a jet pump. The system may include a current feedback input port configured to receive a current measurement based on an output power of the fuel cell, the controller further configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the current measurement. The system may include a current feedback input port configured to receive a current measurement based on an input power of a compressor configured to supply oxygen to the cathode manifold, the controller further configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the current measurement. The controller may be configured to control the hydrogen pressure based on a predetermined control model. The system may include a humidity controller configured to control a humidity level of the hydrogen mixture. The system may include a nitrogen separator configured to reduce a nitrogen level of at least one of the overflow hydrogen or hydrogen mixture. The controller may be further configured to control a variable pressure control valve configured to control the pressure of the overflowed hydrogen.

[0027] In an exemplary embodiment, a method of controlling anode manifold pressure in a hydrogen fuel cell includes measuring an anode manifold pressure, measuring a cathode manifold pressure, determining a differential pressure value based on the measured anode manifold pressure and the measured cathode manifold pressure, and controlling at least one of a hydrogen pressure regulator, a hydrogen recirculation module, or an anode outlet valve based on the determined differential pressure.

[0028] Various implementations may include some, all, or none of the following features. The method may include receiving pressurized hydrogen, regulating the received pressurized hydrogen to a regulated pressure by a hydrogen pressure regulator, receiving overflow hydrogen from an anode manifold, mixing the received pressurized hydrogen from the hydrogen pressure regulator with the received overflow hydrogen by a hydrogen recirculation module, and providing the hydrogen mixture to a hydrogen outlet. Controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the determined differential pressure may include controlling the anode manifold pressure such that the differential pressure is approximately zero. The method may include receiving a current measurement based on an output power of the hydrogen fuel cell and controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the received current measurement. The method may include receiving a current measurement based on a power consumption of a compressor configured to provide oxygen to the cathode manifold and controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the received current measurement. The method may include controlling, by the controller, a humidity control module that controllably adds or removes humidity from the hydrogen mixture based on a predetermined humidity level. The method can include a nitrogen separator module configured to reduce the nitrogen level in at least one of the overflow hydrogen or hydrogen mixture. The method can include controlling the pressure of the overflow hydrogen with a variable pressure control valve.

[0029] In another exemplary embodiment, a hydrogen fuel cell assembly includes a hydrogen fuel cell including an anode manifold, a stack, and a cathode manifold, and a hydrogen fuel cell anode control system having a hydrogen inlet configured to receive pressurized hydrogen, a hydrogen outlet configured to fluidly couple to the anode manifold of the hydrogen fuel cell, a recirculation inlet configured to receive hydrogen overflow from the anode manifold, a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet, a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet, a differential pressure measurement module configured to measure a differential pressure between the anode manifold and the cathode manifold of the hydrogen fuel cell, and a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure.

[0030] The systems and techniques described herein may provide one or more of the following advantages: First, the hydrogen subsystem may provide for rapid implementation of the fuel cell assembly. Second, the system may improve the efficiency of the fuel cell. Third, the system may improve the life of the fuel cell. Fourth, the system may provide a modular solution for the fuel cell assembly that improves the maintainability of the fuel cell system.

[0031] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, drawings, and claims. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a hydrogen fuel cell system.

[0033] [Diagram 2] FIG. 2 is a schematic diagram showing another example of a hydrogen fuel cell system.

[0034] [Diagram 3] FIG. 1 is a perspective view showing an example of an electronic pressure regulator system.

[0035] [Figure 4] FIG. 1 is a perspective view illustrating an example of a jet pump.

[0036] [Diagram 5] 1 is a chart showing an example of a differential pressure.

[0037] [Figure 6] 4 is a flow chart illustrating an example of a hydrogen supply control process in a hydrogen fuel cell.

[0038] [Figure 7] FIG. 1 is a schematic diagram illustrating an example of a typical computer system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Described herein are systems and techniques for controlling hydrogen supply in a hydrogen fuel cell. In general, an anode fuel module is configured with fluid flow conduits, control loop electronics, controllable valves, and associated components as an integrated module that can be used in combination with a hydrogen fuel cell stack to rapidly implement useful hydrogen fuel cell applications. In general, the anode fuel module is configured to control the flow of hydrogen to the fuel cell anode based on electrical demand, control the amount of oxygen (e.g., air) at the fuel cell cathode, control the amount of nitrogen and water at the fuel cell anode, monitor and control the differential pressure across the fuel cell membrane, and provide efficient recirculation of hydrogen at the anode (positive electrode).

[0040] FIG. 1 is a schematic diagram of an example of a hydrogen fuel cell system 100. The system 100 includes a hydrogen fuel cell 110 with an anode manifold 112 of negative anode membrane 113, a stack 114, and a cathode manifold 116 of positive cathode membrane 117. The anode manifold 112 is configured to receive hydrogen fuel, and the cathode manifold is configured to receive oxygen 120, typically from air 122 compressed or otherwise supplied by a compressor 124. In a hydrogen fuel cell, a catalyst in the anode manifold separates hydrogen molecules into protons and electrons, which travel in different paths to the cathode. The electrons travel through a power outlet 120 to an external circuit, creating a flow of electricity. The protons travel through the stack 114 to the cathode, where they combine with oxygen and electrons to produce water and heat at the exhaust 132.

[0041] The stack 114 generates electricity in the form of direct current (DC) power from electrochemical reactions occurring within the hydrogen fuel cell 110. In the illustrated example, a single hydrogen fuel cell is shown, but in some embodiments, multiple (e.g., tens or hundreds) of fuel cells can be combined. For example, a single fuel cell can typically generate approximately 1V, so in some embodiments, multiple individual fuel cells can be combined in series into a fuel cell stack. For example, some fuel cell stacks include hundreds of fuel cells. In some embodiments, the amount of power generated by a fuel cell can depend on various factors, such as the type of fuel cell, the size of the cells, the operating temperature, and the pressure of the gas supplied to the cells.

[0042] The anode manifold 112 includes a collection of catalyst layers. In some embodiments, the catalyst layers can include nanometer-sized platinum particulates dispersed on a carbon support with a large surface area. The platinum particulate catalyst can be mixed with an ionically conductive polymer (e.g., an ionomer) and disposed between the membrane and a gas diffusion layer (GDL). In the anode manifold 112, the platinum catalyst allows hydrogen molecules to be separated into protons and electrons. In the cathode manifold 116, the platinum catalyst allows oxygen reduction by reacting with protons generated in the anode manifold 112 to produce water. When mixed into the catalyst layers, the ionomer allows protons to pass through these layers while being non-conductive, and the electrons generated can be moved through an electrical circuit to generate electricity.

[0043] A GDL (not shown) is disposed outside the catalyst layer and configured to carry reactant gases to the catalyst layer and remove water produced by the reaction. In some embodiments, the GDL can be made of a sheet of carbon paper with carbon fibers partially coated with polytetrafluoroethylene (PTFE). Gases diffuse quickly through the pores of the GDL, which are kept open by the hydrophobic PTFE to prevent excess water accumulation. In some embodiments, the inner surface of the GDL can be coated with a thin layer of high surface area carbon mixed with PTFE (e.g., a microporous layer). The microporous layer can help balance water retention (e.g., to help maintain the electrical conductivity of the membrane) and water release (e.g., to keep the pores open so that hydrogen and oxygen can diffuse to the anode manifold 112 and cathode manifold 116).

[0044] The compressor 124 is configured to compress atmospheric air received at an inlet and deliver it at a predetermined pressure to an outlet fluidly connected to the inlet of the cathode manifold 116 by a fluid conduit. Generally, fuel cell performance improves with higher reactant gas pressures. The pressure in the anode manifold 112 is generated by a supply of pressurized hydrogen entering the anode manifold and exiting through a flow controller 119 (e.g., a fixed or variable orifice). The pressure in the cathode manifold 116 is based on the pressure delivered from the compressor 124.

[0045] In some embodiments, the compressor 124 can be configured to increase the pressure of the inlet air 122 to about 2-4 times the ambient atmospheric pressure. However, if the pressures of the reactant gases in the anode manifold 112 and cathode manifold 116 are unbalanced, a pressure differential 134 can form across the membranes 113, 116 and stack 114. Because excessive pressure differentials (e.g., differences above a predetermined tolerance range around zero) can damage the membranes 113, 116, it is necessary to keep the reactant gas pressures relatively equal to prevent, eliminate, or otherwise reduce the pressure differential 134.

[0046] A hydrogen fuel cell anode control system 150 is provided to control the flow of hydrogen to the fuel cell 110 and to control the differential pressure 134. In general, the system 150 is configured as a modular system that can be quickly connected to the fuel cell 110 with a hydrogen fluid circuit to enable rapid deployment and setup of a hydrogen fuel cell solution, and can control the differential pressure across the fuel cell membrane by actively controlling the hydrogen flow based on a closed feedback loop.

[0047] The system 150 includes a hydrogen inlet port 152 configured to be coupled to a pressurized hydrogen source and receive pressurized hydrogen 154 at a predetermined pressure, and a hydrogen outlet port 156 configured to couple to a fluid conduit configured to supply pressurized hydrogen 158 to the anode manifold 112. The system 150 also includes a recirculation inlet port 160 coupled to a fluid conduit that also couples to an outlet of the anode manifold 112. The recirculation inlet port 160 is configured to receive recirculated (e.g., overflow hydrogen) gas 162 from the anode manifold 122. Because the recirculated gas 162 may be rich in unconsumed hydrogen, the system 150 is configured to maintain hydrogen efficiency by recirculating unused hydrogen through the system 100 and using the pressurized hydrogen 158 to replenish hydrogen consumed by the fuel cell 110.

[0048] Replenishment of hydrogen consumed is accomplished by an electronically controlled pressure regulator system (EPRS) 170 and a jet pump 172. The EPRS 170 is configured to receive pressurized hydrogen 158 and controllably reduce the pressure to a usable level. An example of an EPRS 170 is described in detail in U.S. Patent Application No. 11,092,091, filed March 19, 2018, the contents of which are incorporated herein by reference. The EPRS 170 is controlled by a controller 174 and is configured to control the replenishment of hydrogen consumed by the fuel cell 110 and to control the overall pressure for supplying hydrogen to the fuel cell 100.

[0049] The jet pump 172 is configured to recirculate unconsumed hydrogen (due to operating excess) from the stack 113 back to the hydrogen feed mechanism. The operation of the jet pump 172 is controlled by a controller 174. Examples of jet pumps 172 are described in detail in U.S. Patent Application No. 10,316,803, filed September 25, 2017, and U.S. Patent Application No. 10,995,705, filed February 7, 2019, the contents of which are incorporated herein by reference. In U.S. Patent No. 10,316,803, the jet pump is used in the context of exhaust gas recirculation (EGR), while the example jet pump 172 is used to recirculate overflow hydrogen. As will be described in more detail below, the jet pump 172 has two inlets and one outlet, one inlet (e.g., configured to receive a secondary fluid) configured to be fluidly coupled to the anode manifold 112 to receive recycled hydrogen, and the other inlet (e.g., configured to receive a primary pressurized fluid) configured to be coupled to the EPRS 170 to receive fresh hydrogen. The jet pump is configured with converging / diverging flow paths configured to create a Venturi effect where the fresh flow draws, sucks, pumps, or otherwise promotes the flow of recycled gas into the fresh hydrogen flow. The fresh and recycled hydrogen are mixed within the jet pump 172 and discharged from the outlet, where pressure is restored by converting velocity to pressure through appropriately designed area expansion. In some embodiments, the Venturi effect of the jet pump 172 allows the jet pump 172 to promote the flow of recycled gas without the use of an impeller or other moving parts. In some configurations, the jet pump 172 may be used with a powered impeller to reduce the total externally supplied pump power, which represents parasitic power consumption and therefore reduces the overall system electrical efficiency. As will be described in more detail below, a controller 174 is configured to control the operation of the EPRS 170 and the jet pump 172, and to control the anode exit orifice, as necessary, to control the pressure within the anode manifold 112.

[0050] The system 150 further includes a nitrogen separator 176 and a nitrogen purge valve 178. The nitrogen separator is fluidly coupled to the outlet of the jet pump 172. During operation of the fuel cell 110, nitrogen migrates from the air in the cathode manifold 116 across the stack to the anode manifold 112 (e.g., nitrogen crossover). However, nitrogen accumulates over time, and its presence in the flow to the anode manifold 112 takes up volume that could be occupied by hydrogen, plugging the membrane pores and limiting hydrogen access to the GDL, reducing the amount of hydrogen present at a selected pressure, and reducing the efficiency of the system 100. The nitrogen separator 176 is configured to remove nitrogen from the flow (e.g., reducing the nitrogen content to about 5% or less) and remove the nitrogen from the system 100 through the purge valve 178. However, removing the nitrogen frees up molecular volume in the anode flow, causing a drop in anode pressure. Nitrogen separator 176 and nitrogen purge valve 178 are controlled by controller 174. In some implementations, controller 174 may control nitrogen separator 176 based in part on the gas pressure in anode manifold 112. In some embodiments, the nitrogen separator may be omitted, and hydrogen in the recirculation loop with nitrogen may also be purged, resulting in a loss of consumable hydrogen as well. This may result in a loss of approximately 5-7% of hydrogen consumption, resulting in a significant overall efficiency loss.

[0051] The system 150 further includes a humidity controller 180 and a condensate purge valve 182. The humidity controller 180 is fluidly coupled to the outlet of the nitrogen separator 176. During operation of the fuel cell 110, hydrogen gas in the anode manifold 112 combines with oxygen from the air supplied to the cathode manifold 116 to form water, and additional water (e.g., ambient humidity in the air) may crossover from the cathode manifold 116 to the anode manifold 112. However, this humidity needs to be controlled to facilitate efficient and long-term operation of the fuel cell 110. In some embodiments, the humidity controller may be controlled by the controller 174. In some embodiments, the humidity controller 180 may operate independently (e.g., based on a predetermined humidity threshold level).

[0052] Excessive humidity can block the pores in the membranes 113, 117 and reduce the efficiency of the fuel cell 110. Humidity controller 180 is configured to controllably reduce the humidity in the hydrogen stream to a predetermined humidity level and remove the extracted water through purge valve 182. However, because water occupies a volume of the hydrogen stream to the anode manifold, removing the humidity can cause a drop in pressure. As will be described in more detail below, controller 174 is configured to control the pressure in the anode manifold 112.

[0053] Insufficient humidity can also be detrimental to the fuel cell. For example, membranes 113, 117 generally do not function properly when dry and may eventually crack or break, leading to reduced fuel cell efficiency and / or system failure. Humidity controller 180 is configured to receive the inflow of water 184 and controllably humidify the hydrogen stream to a predetermined humidity level. However, because water occupies volume within the hydrogen stream, the addition of humidity can cause a change in pressure in the anode manifold 112. As will be described in more detail below, controller 174 is configured to control the pressure in the anode manifold 112.

[0054] The controller 174 is configured to receive temperature and pressure signals representative of the temperature and pressure in the anode manifold 112 from the anode sensor 138 configured as a pressure and temperature sensor. In some embodiments, the functions of the temperature and pressure sensors may be provided by separate sensors. The controller 174 is also configured to receive a pressure signal representative of the pressure in the cathode manifold 116 from the cathode sensor 139 configured as a pressure sensor. The controller 174 is configured to determine the differential pressure 136 by comparing the difference between the signals provided by the pressure sensor 138 and the pressure sensor 139. In some implementations, the pressure and temperature signals may be used by the controller 174 to perform a feedback control based on a model of the pressure in the anode manifold 112. In some embodiments, a true "delta pressure sensor" may be used instead of two independent pressure sensors due to control accuracy requirements (±1%), and in some implementations, the differential pressure target may be about 100-200 mbar and the supply pressure may be about 1-4 bar absolute.

[0055] Fuel metering valve 161 is configured to control the exit flow area of ​​anode manifold 112. By controlling valve 161, controller 174 can control the back pressure within anode manifold 112. Additionally, jet pump 172 can be used for recirculation flow measurement.

[0056] Controller 174 is configured to control the pressure in anode manifold 112 based on differential pressure 134 and the sensed temperature. For example, differential pressure 134 can represent the amount of pressure change needed. If additional pressure is needed, controller 174 can control EPRS 170 to admit more fresh hydrogen into the hydrogen stream, controller 174 can control jet pump 172 to decrease the amount of recycled hydrogen admitted back into the hydrogen stream (e.g., to create backpressure by actuating one or more valves and / or variable area nozzles configured to control fresh and / or recycled flow through jet pump 172), and / or controller 174 can control valve 161 or valve 119 to increase backpressure in anode manifold 112. If the pressure is too high, controller 174 can control EPRS 170 to reduce the flow of fresh hydrogen into the hydrogen stream, control jet pump 172 (e.g., by actuating one or more valves in jet pump 172 that control the recirculation and / or fresh flows) to increase the amount of recycled hydrogen re-entered into the hydrogen stream, and / or control valve 161 to reduce the backpressure in anode manifold 112, and can also open the nitrogen purge valve if a rapid pressure reduction is required. As hydrogen is consumed in the fuel cell, the pressure in anode manifold 112 decreases. In some implementations, the humidity of the hydrogen stream can be measured and used by controller 174 to perform feedback control based on a model of the pressure in anode manifold 112.

[0057] The controller 174 may also control the humidity controller 108 to add or remove volumetric occupying water from the hydrogen stream, thereby controlling the pressure. The controller 174 may also control the nitrogen separator 176 to selectively remove or retain nitrogen in the hydrogen stream, thereby controlling the pressure. In some embodiments, the nitrogen concentration in the hydrogen stream may be measured and used by the controller 174 to perform model-based feedback control of the pressure in the anode manifold 112.

[0058] The controller 174 is also configured to control the pressure based on the amount of hydrogen consumed by the fuel cell 110. The current sensor 190 is configured to sense the amount of current of the power output 130 of the fuel cell 110 and provide a current measurement signal to the controller 174. Because the amount of hydrogen consumed by the fuel cell 110 is proportional to the amount of power output 130 produced, the controller 174 can model, estimate and / or predict the amount of additional hydrogen required from the pressurized hydrogen 154 to make up for the consumption.

[0059] The controller 174 is also configured to perform feedforward control (e.g., model-based) of the pressure in the anode manifold 112. The current sensor 191 is configured to sense the amount of current of the input power 192 to the compressor 124 and provide a current measurement signal to the controller 174. Because the amount of pressure provided to the cathode manifold 116 is proportional to and / or predicted from the pressure that may be present in the cathode manifold 116, the current signal from the current sensor 191 may be used by the controller 174 to model and estimate the current pressure in the cathode manifold 116 and / or predict future pressure in the cathode manifold 116.

[0060] In some embodiments, a "heads-up" power request from the external fuel cell system controller can improve performance. In some implementations, a power setpoint can be specified and the external fuel cell system controller can ramp the compressor to the new setpoint over a finite, predetermined period of time. In some examples, this can be sensed in advance, allowing the controller 174 to predict the need for make-up hydrogen and accurately match hydrogen consumption through a feed-forward model, while managing recirculation and other flows to maintain anode manifold pressure and maintain transmembrane differential pressure. The controller 174 can monitor the cathode manifold pressure, while the external fuel cell system controller can specify a rate of change and / or target pressure value for the cathode manifold 116. For example, the controller 174 can bridge uncertain information such as fuel cell output current, current to the compressor, and information from known mathematical-physical relationships (e.g., models) and can identify current and / or future hydrogen demand that is an input to the physical model, and the output can be actuator settings configured to meet changes in consumption demand while maintaining very small deviations in differential pressure across the membrane.

[0061] Figure 2 is a schematic diagram of another example hydrogen fuel cell system 200. In general, system 200 is substantially similar to the example system 100 of Figure 1, with a hydrogen fuel cell anode control system 250, a pressure regulator 270 replacing EPRS 170, and a recirculation pump 272 replacing EGR system 172.

[0062] In some embodiments, pressure regulator 270 may be a fixed pressure regulator configured to regulate the pressure of pressurized hydrogen 154 to a predetermined fixed pressure. In some embodiments, pressure regulator 270 may be a manually adjustable pressure regulator that can be set to a predetermined pressure. In some embodiments, pressure regulator 270 may be a controllable pressure regulator. For example, pressure regulator 270 may be controlled by controller 174 to a control pressure pre-specified by controller 174.

[0063] The recirculation pump 272 is an anode recirculation blower and is configured to recirculate unconsumed hydrogen (due to operating excess) from the stack 113 back into the hydrogen stream. The operation of the recirculation pump 272 is controlled by the controller 174.

[0064] 3 is a perspective view of an example electronic pressure regulator system (EPRS) 300. In some embodiments, the EPRS 300 may be the example EPRS 170 of FIG.

[0065] The EPRS 300 includes an inlet 310 and an outlet 320, and a valve 330 configured to selectively allow, restrict, and / or block flow from the inlet 310 to the outlet 320. The valve 330 is actuated by an actuator 340 configured to be controlled by an external controller (e.g., controller 174 of FIG. 1). The EPRS 300 uses a ported ball valve for high accuracy and large scale blockage, and is actuated by a rotary valve with sufficient torque capability to precisely move the valve. In some embodiments, the EPRS 300 can also implement a model-based mathematical process that allows it to measure the hydrogen primary flow rate.

[0066] 4 is a perspective view of an example jet pump 400. In some embodiments, the jet pump 400 may be the example jet pump 172 of FIG.

[0067] The jet pump 400 is comprised of one or more housings or casings 402. Openings in the end walls of the casing define hydrogen inlets 410 and outlets 420 of an internal flow passage 422 defined by the casing 402. The internal flow passage 422 directs flow from the hydrogen inlet 410 to the outlet 420, allowing flow through the jet pump 400. The jet pump 400 includes a convergent nozzle within the casing 402 in a flow passage from the hydrogen inlet 410 to the outlet 420. The convergent nozzle includes a converging portion that converges in the flow direction toward the converging end. That is, the downstream end (outlet) of the convergent nozzle has a smaller cross-sectional area, e.g., smaller flow area, than the upstream end (inlet) of the convergent nozzle. The convergent nozzle may include a portion that does not converge and remains relatively straight without changing the cross-sectional flow area. Such a portion may be used to retain the convergent nozzle within the jet pump 400. The jet pump 400 includes a gas receiving housing 430 that includes one or more gas inlets 432 that are fluidly connected to a recirculation flow (e.g., connected to the exemplary recirculation inlet port 160 and receiving recirculated gas 162) that feeds into an internal receiving cavity of the gas housing 430. In the illustrated embodiment, the housing 430 surrounds the convergent nozzle such that a portion of the convergent nozzle is within the internal receiving cavity 422. The convergent nozzle is positioned to form a free jet of gas from a converging end of the convergent nozzle. Additionally, the gas inlet 432 is upstream of the converging end of the convergent nozzle. Although the illustrated embodiment shows the convergent nozzle at least partially within the gas receiving housing 430, other designs may be utilized.

[0068] The convergent-divergent nozzle is downstream of the converging portion of the convergent nozzle and is fluidly coupled to receive the fluid stream from the converging end, gas inlet 432. To promote mixing, the inlet of the convergent-divergent nozzle has a larger area than the outlet of the convergent nozzle. The convergent-divergent nozzle includes three sections: a hydrogen inlet 410, a throat, and an outlet 420. The throat is the narrowest point of the convergent-divergent nozzle and is downstream of and fluidly connected to the hydrogen inlet 410 of the convergent-divergent nozzle. The narrowing of the convergent-divergent nozzle at the throat increases the flow rate of the fluid stream passing through the convergent-divergent nozzle. The outlet 420 of the convergent-divergent nozzle is fluidly connected to and upstream of the anode manifold 112. Between the throat and the outlet 420, the cross-sectional area of ​​the flow path through the convergent-divergent nozzle increases. The increased cross-sectional area slows the flow rate and increases the pressure of the fluid stream. In some cases, the increase in cross-sectional area can be sized to increase the pressure within the jet pump 400 such that the pressure drop across the jet pump 400 is zero, a nominal value, or an otherwise small value.

[0069] FIG. 5 is a differential pressure chart 500. Chart 500 shows an example anode manifold pressure (P1), an example cathode manifold pressure (P2), and a differential pressure P3=P2-P1. Some existing fuel cells are designed such that the cathode pressure is the higher of the two pressures. Chart 500 shows that during a power-up transient, the pressures at P1 and P2 decrease due to increased stack hydrogen and air consumption. Chart 500 shows an example of how model-based control can be used to manage hydrogen flow to manage the anode pressure within a given tolerance of the independently controlled cathode manifold pressure differential.

[0070] 6 is a flow chart illustrating an example of a hydrogen supply control process 600 in a hydrogen fuel cell. In some embodiments, the process 600 may be performed by the example controller 174 of FIGS.

[0071] At 610, the anode manifold pressure is measured. For example, the controller 174 can read a pressure signal from the sensor 138 to measure the pressure in the anode manifold 112.

[0072] The cathode manifold pressure is measured at 620. For example, the controller 174 can read a pressure signal from the sensor 139 to measure the pressure in the cathode manifold 116.

[0073] At 630, a differential pressure value is determined based on the measured anode manifold pressure and the measured cathode manifold pressure. For example, controller 174 can compare (e.g., subtract) a pressure value determined from sensor 138 and a pressure value determined from sensor 139 to determine differential pressure 134.

[0074] At 640, at least one of the hydrogen pressure regulator or the hydrogen recirculation module is controlled based on the determined differential pressure. For example, the controller 174 may control the operation of one or both of the EPRS module 170 or the jet pump 172 to increase or decrease the pressure in the anode manifold 112 and drive the differential pressure 134 toward zero or another suitable predetermined value.

[0075] 7 is a schematic diagram of an example of a general computer system 700. System 700 may be used, according to one embodiment, for the operations described in connection with method 300. For example, system 700 may be included in example controller 174 of FIGS.

[0076] The system 700 includes a processor 710, a memory 720, a storage device 730, and an input / output device 740. Each of the components 710, 720, 730, and 740 are interconnected using a system bus 750. The processor 710 is capable of processing instructions for execution within the system 700. In one embodiment, the processor 710 is a single-threaded processor. In another embodiment, the processor 710 is a multi-threaded processor. The processor 710 is capable of processing instructions stored in the memory 720 or the storage device 730 to display graphical information in a user interface on the input / output device 740.

[0077] The memory 720 stores information within the system 700. In one embodiment, the memory 720 is a computer readable medium. In one embodiment, the memory 720 is a volatile memory unit. In another embodiment, the memory 720 is a non-volatile memory unit.

[0078] The storage device 730 is capable of providing mass storage for the system 700. In one embodiment, the storage device 730 is a computer readable medium. In various different implementations, the storage device 730 may be a floppy disk drive, a hard disk drive, an optical disk drive, or a tape drive.

[0079] The input / output device 740 provides input and output operations to the system 700. In one embodiment, the input / output device 740 includes a keyboard and / or a pointing device. In another embodiment, the input / output device 740 includes a display device for displaying a graphical user interface.

[0080] The described functions can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. The apparatus can be implemented in a computer program product tangibly embodied in an information carrier, e.g., a machine-readable storage device, for execution by a programmable processor, and the method steps can be performed by the programmable processor executing a program of instructions to perform the functions of the described implementation by operating on input data and generating output. The described functions can be advantageously implemented in one or more computer programs executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used by a computer, directly or indirectly, to perform an operation or bring about a result. Computer programs can be written in any type of programming language, including compiled or interpreted languages, and can be deployed in any form, such as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0081] Processors suitable for executing a program of instructions include, by way of example, both general purpose and special purpose microprocessors, as well as the sole processor or one of several processors of any kind of computer. Typically, a processor receives instructions and data from a read-only memory or a random access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data. Typically, a computer also includes, or is operatively coupled to communicate with, one or more mass storage devices for storing data files. Such devices include magnetic disks, such as internal hard disks and removable disks, magneto-optical disks, and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data include, by way of example, semiconductor memory devices, such as EPROMs, EEPROMs, flash memory devices, magnetic disks, such as internal hard disks and removable disks, magneto-optical disks, CD-ROM and DVD-ROM disks, and any form of non-volatile memory. The processor and memory may be supplemented by or incorporated in ASICs (Application Specific Integrated Circuits).

[0082] To provide for interaction with a user, the present features can be implemented on a computer having a display device, such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user, a keyboard by which the user can provide input to the computer, and a pointing device, such as a mouse or trackball.

[0083] The present features may be implemented in a computer system including a back-end component such as a data server, a computer system including a middleware component such as an application server or an Internet server, a computer system including a front-end component such as a client computer having a graphical user interface or an Internet browser, or any combination thereof. The components of the system may be connected by any form or medium of digital data communication, such as a communications network. Examples of communications networks include, for example, a LAN, a WAN, and the computers and networks forming the Internet.

[0084] The computer system may include clients and servers. Clients and servers are generally remote from each other and typically interact through a network as described. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0085] Although several implementations have been described in detail above, other variations are possible. Additionally, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Additionally, other steps may be provided or removed from the described flows, and other components may be added or removed from the described systems. Accordingly, other implementations are within the scope of the following claims.

Claims

1. a hydrogen inlet configured to receive pressurized hydrogen; a hydrogen outlet configured to fluidly couple to an anode manifold of a hydrogen fuel cell; a recirculation inlet configured to receive hydrogen overflow from the anode manifold; a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet; a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet; a differential pressure measurement module configured to measure a differential pressure between the anode manifold and the cathode manifold of the hydrogen fuel cell; a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure. Hydrogen fuel cell anode control system.

2. The controller is configured to control the hydrogen pressure so that the differential pressure is zero.

10. The hydrogen fuel cell anode control system of claim 1.

3. The hydrogen pressure regulator is a controllable gas pressure regulator system.

10. The hydrogen fuel cell anode control system of claim 1.

4. the hydrogen recirculation module comprises a gas recirculation pump; 10. The hydrogen fuel cell anode control system of claim 1.

5. the hydrogen recirculation module comprises a jet pump.

10. The hydrogen fuel cell anode control system of claim 1.

6. a current feedback input port configured to receive a current measurement based on the output power of the hydrogen fuel cell, the controller being further configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the current measurement.

10. The hydrogen fuel cell anode control system of claim 1.

7. a current feedback input port configured to receive a current measurement based on an input power of a compressor configured to supply oxygen to the cathode manifold, wherein the controller is further configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the current measurement.

10. The hydrogen fuel cell anode control system of claim 1.

8. the controller is configured to control the hydrogen pressure based on a predetermined control model; 10. The hydrogen fuel cell anode control system of claim 1.

9. further comprising a humidity controller configured to control the humidity level of the hydrogen mixture.

10. The hydrogen fuel cell anode control system of claim 1.

10. further comprising a nitrogen separator configured to reduce the nitrogen level in at least one of the overflow hydrogen or the hydrogen mixture.

10. The hydrogen fuel cell anode control system of claim 1.

11. the controller is further configured to control a variable pressure control valve configured to control the pressure of the overflowed hydrogen.

10. The hydrogen fuel cell anode control system of claim 1.

12. measuring the anode manifold pressure; measuring the cathode manifold pressure; determining a differential pressure value based on the measured anode manifold pressure and the measured cathode manifold pressure; and controlling at least one of a hydrogen pressure regulator, a hydrogen recirculation module, or an anode outlet valve based on the determined differential pressure. A method for controlling anode manifold pressure in a hydrogen fuel cell.

13. receiving pressurized hydrogen; adjusting the received pressurized hydrogen to a regulated pressure by the hydrogen pressure regulator; receiving overflow hydrogen from the anode manifold; mixing, by a hydrogen recirculation module, pressurized hydrogen received from the hydrogen pressure regulator with the received overflow hydrogen and supplying the hydrogen mixture to a hydrogen outlet. The method of claim 12.

14. and controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the determined differential pressure further comprises controlling the anode manifold pressure so that the differential pressure is zero. The method of claim 12.

15. receiving a current measurement based on the output power of the hydrogen fuel cell; and controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the received current measurements.

13. The method of any one of claims 12.

16. receiving a current measurement based on power consumption of a compressor configured to supply oxygen to the cathode manifold; and controlling at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the received current measurements. The method of claim 12.

17. The method of claim 16, further comprising the step of controlling, by a controller, a humidity control module to controllably add or remove humidity from the hydrogen mixture based on a predetermined humidity level. The method of claim 13.

18. The method of claim 1 further comprising the step of controlling, by a controller, a nitrogen separator module to reduce the nitrogen level of at least one of the overflow hydrogen or the hydrogen mixture. The method of claim 13.

19. Further comprising controlling the pressure of the overflowed hydrogen by variable pressure control. The method of claim 13.

20. a hydrogen fuel cell comprising an anode manifold, a stack, and a cathode manifold; 1. A hydrogen fuel cell anode control system comprising: a hydrogen inlet configured to receive pressurized hydrogen; a hydrogen outlet configured to fluidly couple to an anode manifold of a hydrogen fuel cell; a recirculation inlet configured to receive hydrogen overflow from the anode manifold; a hydrogen pressure regulator configured to receive pressurized hydrogen from the hydrogen inlet; a hydrogen recirculation module configured to mix hydrogen received from the hydrogen pressure regulator and the recirculation inlet and provide a hydrogen mixture to the hydrogen outlet; a differential pressure measurement module configured to measure a differential pressure between the anode manifold and the cathode manifold of the hydrogen fuel cell; a controller configured to control at least one of the hydrogen pressure regulator or the hydrogen recirculation module based on the measured differential pressure; Hydrogen fuel cell assembly.

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