Hydrogen recycle pump heating and sealing assembly and method

Abstract

A recirculation pump includes an impeller, a pump motor assembly, and a heater. The pump motor assembly includes a pump housing and a pump motor: the pump housing is disposed axially away from the impeller and contains a pump cavity therein; the pump motor is disposed in the pump cavity and drives the impeller. The heater is disposed on or in the pump housing and is spaced apart from the impeller. The heater is configured to increase the temperature of any portion of fluid that leaks from the impeller into the pump cavity and resides in the pump cavity. The increase in temperature causes the fluid residing in the pump cavity to flow toward the impeller and out of the pump cavity.

Description

Technical Field

[0001] This disclosure relates broadly to fuel cell components, and in particular to hydrogen recirculation pumps for fuel cell components.

[0002] Cross-references to related applications

[0003] This non-provisional application claims the benefit and priority of U.S. Provisional Application Serial No. 63 / 379,557, filed October 14, 2022, pursuant to 35 U.S. SC §119(e) and any other applicable law or regulation, the entire contents of which are hereby expressly incorporated by reference. Background Technology

[0004] A monolithic fuel cell is one of many repeating units in a fuel cell stack, providing electricity or power for personal and / or industrial applications. A typical proton exchange membrane (PEM) fuel cell consists of many fuel cell modules that are compressed and bundled together to form a fuel cell stack. A PEM fuel cell comprises several components, typically including a centrally located membrane electrode assembly (MEA), gas diffusion layers (GDLs) on either side of the MEA, and bipolar plates (BPPs) on either side of the GDLs. The MEA is used to generate the electrochemical reactions within the fuel cell and / or fuel cell stack. Generally, PEM fuel cells and / or fuel cell stacks are assembled from these components to operate in a useful and reliable manner.

[0005] In many mobile applications, fuel cells use pure hydrogen for the anode and an oxidant for the cathode. To avoid onboard storage, the oxygen in the cathode is supplied from the atmosphere, and is therefore usually accompanied by nitrogen. The pure hydrogen at the anode is typically supplied by highly compressed gaseous hydrogen or liquefied hydrogen stored in an onboard tank. A cooling system typically requires a radiator to manage excess heat generated during the electrochemical reaction and to maintain the fuel cell at an appropriate temperature during operation.

[0006] A typical PEM fuel cell uses a hydrogen recirculation pump (HRP) to continuously supply fresh hydrogen to the PEM anode side. PEM fuel cells consume hydrogen and therefore must be replenished. When replenishing hydrogen, it is crucial to allow the hydrogen to flow within the PEM cell to achieve peak performance.

[0007] When reactant gas molecules are present in the active region, the MEA generates a voltage potential, and the current consumption or load is supported by the reactant flow rate. During power generation, moisture is generated on the anode side of the battery, humidifying the hydrogen fuel and forming humidified water. There are several ways to move or pump the (now humidified) hydrogen. Various types of pumps can be used as ejector-type systems. For pump-based systems, the amount of water remaining inside the pump (pump motor cavity) after the humidified hydrogen condenses should be minimized, as this is crucial for extending the pump's lifespan.

[0008] Therefore, it would be highly beneficial for fuel cell components, especially pump systems, to be able to remove water from the pump motor cavity, or even completely prevent water from entering the cavity.

[0009] Overview

[0010] According to a first aspect of this disclosure, a recirculation pump for a fuel cell system includes an impeller, a pump motor assembly, and at least one heater. The impeller is configured to rotate and push fluid from an inlet to an outlet. The pump motor assembly includes a pump housing and a pump motor: the pump housing is arranged axially away from the impeller and contains a pump chamber; the pump motor is arranged in the pump chamber and configured to drive the impeller. The at least one heater is disposed on or therein of the pump housing and spaced apart from the impeller; the at least one heater is configured to increase the temperature of any portion of the fluid leaking from the impeller into the pump chamber and residing in the pump chamber. The increase in temperature causes the fluid residing in the pump chamber to flow toward the impeller and exit the pump chamber.

[0011] In some embodiments, the recirculation pump further includes an impeller assembly having an impeller housing with an impeller chamber and an inlet and an outlet spaced apart on a first side of the impeller housing. Each inlet and outlet communicates with the impeller chamber. The impeller assembly also includes an impeller disposed in the impeller chamber and configured to push fluid entering the impeller chamber from the inlet to the outlet, such that the fluid exits the impeller housing through the outlet.

[0012] In some embodiments, the pump housing is disposed on a second side of the impeller housing, opposite to the first side; and the first heater of the at least one heater is disposed on the second side of the pump housing, opposite to the first side of the pump housing facing the impeller housing. The second heater of the at least one heater is axially disposed on the outer surface of the pump housing between the first and second sides. The axial position of the second heater is closer to the second side of the pump housing and farther from the first side.

[0013] In some embodiments, at least one additional heater and a second heater of the at least one heater are axially arranged on the outer surface of the pump housing between the first and second sides of the pump housing. The pump motor is connected to the impeller via a drive shaft, wherein the pump motor drives the rotation of the drive shaft and the impeller.

[0014] In some embodiments, the recirculation pump further includes a bearing assembly axially arranged between the pump motor assembly and the impeller assembly. The bearing assembly includes a bearing housing, a first side of which is disposed on a second side of the impeller housing opposite to the first side of the impeller housing and defines a bearing cavity therein; the bearing assembly also includes a bearing seal disposed within the bearing cavity. A drive shaft extends from the pump motor through the bearing cavity to the impeller, wherein the drive shaft is disposed within the bearing seal and is provided with rotational support by the bearing seal.

[0015] In some embodiments, the bearing assembly further includes a lip seal disposed within a bearing cavity between the bearing seal and the impeller, and a grease material disposed within the bearing cavity between the lip seal and the bearing seal; the grease material is arranged adjacent to the bearing seal and distributed around the circumferential outer surface of the drive shaft. The lip seal is arranged to retain the grease material adjacent to the bearing seal so that pressure can escape from the pump cavity and form a seal to block pressure from the impeller cavity. In some embodiments, the lip seal is composed of a fluororubber material, and the grease material is composed of a hydrogen-resistant material. In some embodiments, the grease material is composed of a perfluoropolyether.

[0016] According to another aspect of this disclosure, a recirculation pump for a fuel cell system includes an impeller and a bearing assembly. The impeller includes a drive shaft coupled to the center of the impeller and configured to rotatably push fluid from the impeller inlet to the impeller outlet. The bearing assembly is arranged axially away from the impeller and includes a bearing housing and a bearing seal. The bearing housing has a bearing cavity, and the bearing seal is disposed within the bearing cavity. The drive shaft extends from the impeller through the bearing cavity. The drive shaft is disposed within the bearing seal and is provided with rotational support by the bearing seal. The bearing assembly also includes a lip seal disposed within the bearing cavity and a grease material disposed within the bearing cavity between the lip seal and the bearing seal.

[0017] In some embodiments, the lip seal is arranged to retain grease material between the lip seal and the bearing seal, allowing pressure to escape from the pump chamber and forming a seal to block pressure from the impeller chamber. In some embodiments, the lip seal is made of fluororubber material, and the grease material is made of hydrogen-resistant material. In some embodiments, the grease material is made of perfluoropolyether.

[0018] In some embodiments, the recirculation pump further includes a pump motor assembly and at least one heater. The pump motor assembly includes a pump housing containing a pump chamber, and a pump motor disposed within the pump chamber. A drive shaft is coupled to the pump motor such that the pump motor is configured to drive an impeller; the pump housing is adjacent to a bearing housing and disposed on the side of the bearing housing opposite the impeller. The at least one heater is disposed on or within the pump housing and spaced apart from the bearing housing; the at least one heater is configured to increase the temperature of any portion of the fluid that leaks from the impeller through the bearing chamber into the pump chamber and resides in the pump chamber. The increase in temperature causes the fluid residing in the pump chamber to flow toward the impeller and exit the pump chamber.

[0019] In some embodiments, the first heater of the at least one heater is arranged on the second side of the pump housing, opposite to the first side of the pump housing facing the bearing housing; the second heater of the at least one heater is axially arranged on the outer surface of the pump housing between the first and second sides of the pump housing.

[0020] According to another aspect of this disclosure, a method includes providing a pump motor assembly comprising a pump housing containing a pump chamber, and a pump motor disposed within the pump chamber; at least one heater disposed on or therein of the pump housing and spaced apart from an impeller; rotating the impeller by the pump motor such that the impeller pushes fluid from an impeller inlet to an impeller outlet, wherein the pump housing is disposed axially away from the impeller. The method further includes activating the at least one heater via a controller in response to a shutdown of the fuel cell system to increase the temperature of any portion of fluid leaking from the impeller into the pump chamber and residing in the pump chamber. The temperature increase causes the fluid residing in the pump chamber to flow toward the impeller and exit the pump chamber. The method further includes deactivating the at least one heater via the controller in response to a first time amount that the at least one heater has been activated, based on a first operating condition of the fuel cell system.

[0021] In some embodiments, the first operating condition refers to a temperature rise caused by the at least one heater that causes all fluid residing in the pump chamber to leave the pump chamber. Brief description of the attached diagram

[0022] The following is a detailed description of the contents of this disclosure with reference to the accompanying drawings:

[0023] Figure 1A This is a schematic diagram of an exemplary fuel cell system, which includes an air delivery system, a hydrogen delivery system, and a fuel cell module containing multiple fuel cells.

[0024] Figure 1B This is a cross-sectional view of an exemplary fuel cell system, which includes an air delivery system, multiple hydrogen delivery systems, and multiple fuel cell modules, each module containing multiple fuel cell stacks.

[0025] Figure 1C yes Figure 1A A perspective view of an exemplary repeating unit of the fuel cell stack in the fuel cell system shown.

[0026] Figure 1D yes Figure 1C A cross-sectional view of an exemplary repeating unit of the fuel cell stack shown.

[0027] Figure 2A The diagram shows a cross-sectional view of a hydrogen recirculation pump according to a first aspect of this disclosure, which shows that the hydrogen recirculation pump includes an impeller, a pump motor assembly, and a heater disposed on the pump housing of the pump motor assembly.

[0028] Figure 2B yes Figure 2A A front view of the impeller of the hydrogen recirculation pump is shown.

[0029] Figure 2C yes Figure 2A The diagram shows a cross-sectional view of a hydrogen recirculation pump, in which a heater is arranged in the pump chamber of the pump housing;

[0030] Figure 2D yes Figure 2A The diagram shows a cross-sectional view of a hydrogen recirculation pump, in which the heater is arranged in the outer wall of the pump housing;

[0031] Figure 3 yes Figure 2A The schematic diagram shown illustrates the hydrogen recirculation pump relative to... Figure 1A-1D The arrangement of fuel cell system components in the fuel cell system shown;

[0032] Figure 4A The following is a cross-sectional view of a hydrogen recirculation pump according to another aspect of this disclosure, showing that the hydrogen recirculation pump includes an impeller, a pump motor assembly and a bearing assembly located between the impeller and the pump motor assembly, and showing that the bearing assembly includes a bearing cavity (through which the drive shaft of the pump motor of the pump motor assembly extends), a bearing seal disposed in the bearing cavity around the drive shaft, a lip seal and a grease material disposed in the bearing cavity around the drive shaft and adjacent to the bearing seal;

[0033] Figure 4B yes Figure 4A The diagram shows a cross-sectional view of the bearing seal, lip seal, and grease material of the hydrogen recirculation pump.

[0034] Figure 4C yes Figure 4A The diagram shows a cross-sectional view of the bearing seals, lubricating grease material, and an alternative lip seal of the hydrogen recirculation pump, which is consistent with... Figure 4A and4B The difference of the lip seal shown is that the lip of the alternative lip seal rests on the outer surface of the bearing housing;

[0035] Figure 5 This is a cross-sectional view of a hydrogen recirculation pump according to another aspect of this disclosure, showing that the hydrogen recirculation pump includes a flow heating system configured to pump warm water through a pump chamber, thereby heating the condensate residing in the pump chamber; and

[0036] Figure 6 This is a schematic diagram of the controller and related components used in conjunction with the hydrogen recirculation pump shown in Figures 1-5. Detailed description

[0037] like Figure 1A As shown, the fuel cell system 10 typically includes one or more fuel cell stacks 12 (“STK”) or fuel cell modules 14, which are connected to a nuclear power plant siding (BOP) 16, including various components, to support electrochemical conversion, power generation, and / or power distribution, thereby helping to meet the needs of modern industry and commerce in an environmentally friendly manner. Figure 1B and 1C As shown, the fuel cell system 10 may include a fuel cell stack 12 composed of multiple single fuel cells 20. Each fuel cell stack 12 may accommodate multiple fuel cells 20 assembled together in series and / or parallel. The fuel cell system 10 may include, as shown in the figure... Figure 1A and 1B One or more fuel cell modules 14 are shown.

[0038] Each fuel cell module 14 may contain multiple fuel cell stacks 12 and / or multiple fuel cells 20. The fuel cell module 14 may also contain appropriate combinations of associated structural elements, mechanical systems, hardware, firmware, and / or software to support the function and operation of the fuel cell module 14. Such items include, but are not limited to, piping, sensors, regulators, current collectors, seals, and insulators.

[0039] The fuel cells 20 in the fuel cell stack 12 can be stacked together to multiply and increase the voltage output of a single fuel cell stack 12. The number of fuel cell stacks 12 in the fuel cell system 10 can vary depending on the amount of power required to operate the fuel cell system 10 and meet the power demand of any load. The number of fuel cells 20 in the fuel cell stack 12 can vary depending on the amount of power required to operate the fuel cell system 10 (including the fuel cell stacks 12).

[0040] Each fuel cell stack 12 or fuel cell system 10 may use any number of fuel cells 20. For example, each fuel cell stack 12 may contain approximately 100 to 1000 fuel cells 20, including any specific number or range of fuel cells 20 contained therein (e.g., approximately 200 to 800). In an embodiment, the fuel cell system 10 may contain approximately 20 to 1000 fuel cell stacks 12, including any specific number or range of fuel cell stacks 12 contained therein (e.g., approximately 200 to 800). Within the fuel cell stack 12, the fuel cells 20 within the fuel cell module 14 may be oriented in any direction to optimize the operating efficiency and functionality of the fuel cell system 10.

[0041] The fuel cell 20 in the fuel cell stack 12 can be any type of fuel cell 20. The fuel cell 20 can be a polymer electrolyte membrane or proton exchange membrane (PEM) fuel cell, an anion exchange membrane fuel cell (AEMFC), an alkaline fuel cell (AFC), a molten carbonate fuel cell (MCFC), a direct methanol fuel cell (DMFC), a regenerative fuel cell (RFC), a phosphoric acid fuel cell (PAFC), or a solid oxide fuel cell (SOFC). In an exemplary embodiment, the fuel cell 20 can be a polymer electrolyte membrane or proton exchange membrane (PEM) fuel cell or a solid oxide fuel cell (SOFC).

[0042] exist Figure 1C In one embodiment shown, the fuel cell stack 12 includes a plurality of proton exchange membrane (PEM) fuel cells 20. Each fuel cell 20 includes a single membrane electrode assembly (MEA) 22, and the MEA 22 has a gas diffusion layer (GDL) 24, 26 on one or both sides (see Figure 1C The fuel cell 20 also includes a bipolar plate (BPP) 28, 30, located outside each gas diffusion layer (GDL) 24, 26, such as... Figure 1C As shown. The above-mentioned components, in particular the bipolar plate 30, the gas diffusion layer (GDL) 26, the membrane electrode assembly (MEA) 22, and the gas diffusion layer (GDL) 24, each include a repeating unit 50.

[0043] Bipolar plates (BPPs) 28 and 30 are responsible for transporting reactants, such as fuel 32 (e.g., hydrogen) or oxidant 34 (e.g., oxygen, air), and cooling fluid 36 (e.g., coolant and / or water) within the fuel cell 20. The bipolar plates (BPPs) 28 and 30 can uniformly distribute reactants 32 and 34 to the active region 40 of each fuel cell 20 via oxidant flow fields 42 and / or fuel flow fields 44 formed on the outer surfaces of the bipolar plates (BPPs) 28 and 30. The active region 40 refers to the location where electrochemical reactions occur to generate electricity from the fuel cell 20; when viewed from above, it is located at the center of the membrane electrode assembly (MEA) 22, gas diffusion layers (GDLs) 24 and 26, and bipolar plates (BPPs) 28 and 30.

[0044] Bipolar plates (BPPs) 28 and 30 can be formed separately to create reactive flow fields 42 and 44 on opposite outer surfaces of the bipolar plates (BPPs) 28 and 30, and to create a coolant flow field 52 inside the bipolar plates (BPPs) 28 and 30, such as... Figure 1D As shown. For example, bipolar plates (BPPs) 28, 30 may include: a fuel flow field 44 for transferring fuel 32 on one side of the plates 28, 30 to interact with a gas diffusion layer (GDL) 26; and an oxidant flow field 42 for transferring oxidant 34 on a second, opposite side of the plates 28, 30 to interact with a gas diffusion layer (GDL) 24. Figure 1D As shown, the bipolar plates (BPPs) 28 and 30 may also include coolant flow fields 52 formed within the plates (BPPs) 28 and 30, which are typically centered between the opposite outer surfaces of the plates (BPPs) 28 and 30. The coolant flow fields 52 facilitate the flow of cooling fluid 36 through the bipolar plates (BPPs) 28 and 30 to regulate the temperature of the plate (BPPs) 28 and 30 materials and the reactants.

[0045] 28 and 30 are pressed onto adjacent gas diffusion layers (GDLs) 24 and 26 to isolate and / or seal one or more reactants 32 and 34 within their respective channels 44 and 42, thereby maintaining conductivity, which is necessary for the robust operation of the fuel cell 20 (see [link to relevant documentation]). Figure 1C and 1D ).

[0046] The fuel cell system 10 described herein can be used in stationary and / or immobile power systems, such as industrial applications and power plants. The fuel cell system 10 can also be implemented in conjunction with an air delivery system 18. Furthermore, the fuel cell system 10 can also be implemented in conjunction with a hydrogen delivery system and / or a hydrogen source 19, such as a pressurized tank, including a gaseous pressurized tank, a cryogenic liquid storage tank, a chemical storage unit, a physical storage unit, a stationary storage unit, an electrolysis system, or an electrolyzer. In one embodiment, the fuel cell system 10 is connected and / or attached to a hydrogen delivery system and / or a hydrogen source 19 in series or parallel, such as one or more hydrogen delivery systems and / or hydrogen sources 19 in BOP 16 (see...). Figure 1A In another embodiment, the fuel cell system 10 is not connected in series or parallel and / or attached to the hydrogen delivery system and / or hydrogen source 19.

[0047] In some embodiments, the fuel cell system 10 may include an on / off valve 10XV1, a pressure sensor 10PT1, a mechanical regulator 10REG, and a venturi tube 10VEN, arranged to functionally communicate with each other and located downstream of the hydrogen delivery system and / or hydrogen source 19. The pressure sensor 10PT1 may be positioned between the on / off valve 10XV1 and the mechanical regulator 10REG. In some embodiments, a proportional control valve may be used instead of the mechanical regulator 10REG. In some embodiments, a second pressure sensor 10PT2 is positioned downstream of the venturi tube 10VEN, which is located downstream of the mechanical regulator 10REG.

[0048] In some embodiments, the fuel cell system 10 may further include a recirculation pump 10REC located downstream of the fuel cell stack 12 and functionally connected to a venturi tube 10VEN. The fuel cell system 10 may further include an on / off valve 10XV2 located downstream of the fuel cell stack 12 and a pressure transmission valve 10PSV.

[0049] This fuel cell system 10 can also be included in mobile applications. In an exemplary embodiment, the fuel cell system 10 is for a vehicle and / or powertrain 100. The vehicle 100 including this fuel cell system 10 can be an automobile, motor vehicle, bus, truck, train, locomotive, aircraft, light vehicle, medium vehicle, or heavy vehicle. The type of vehicle 100 may also include, but is not limited to: commercial vehicles and engines, trains, trolleybuses, trams, aircraft, buses, ships, vessels, and other known vehicles, as well as other machinery and / or manufacturing equipment, equipment, facilities, etc.

[0050] The vehicle and / or powertrain 100 can be used on roads, highways, railways, air routes, and / or waterways. The vehicle 100 can be used in applications including, but not limited to, off-highway transportation, vehicles, and / or mining equipment. For example, an exemplary embodiment of the mining equipment vehicle 100 is a mining truck or an ore transport truck.

[0051] Furthermore, those skilled in the art will understand that the fuel cell system 10, fuel cell stack 12, and / or fuel cell 20 described in this disclosure can replace any electrochemical system, including electrolysis systems (e.g., electrolyzers), electrolyzer arrays, and / or electrolyzer cells (ECs). Therefore, in some embodiments, the features and aspects described and taught in this disclosure concerning the fuel cell system 10, stack 12, or cell 20 also relate to electrolyzers, electrolyzer arrays, and / or ECs. In other embodiments, the features and aspects described in this disclosure are independent of and can be distinguished from the features and aspects of electrolyzers, electrolyzer arrays, and / or ECs.

[0052] This disclosure relates to systems, components, and methods for removing water from and / or completely preventing water from entering the pump motor cavity of a hydrogen recirculation pump. This is achieved through the hydrogen recirculation pumps 110, 210, 310 (e.g., Figure 2A , Figure 4A and Figure 5 (As shown) This hydrogen recirculation pump includes a heater configured to heat water residing in the pump chamber, causing the water to leave the pump chamber, and / or includes a seal to prevent water from entering the pump chamber. The hydrogen recirculation pumps 110, 210, and 310 disclosed herein are also resistant to damage caused by the interaction of hydrogen flowing outside the pump chamber with the seal. The hydrogen recirculation pumps 110, 210, and 310 disclosed herein can be used in conjunction with the aforementioned fuel cell system 10. Those skilled in the art will understand that the components and methods described herein regarding the hydrogen recirculation pumps 110, 210, and 310 are applicable to other types of pumps, including alternative types of recirculation pumps.

[0053] Figure 2A A cross-sectional view of a hydrogen recirculation pump 110 according to a first aspect of this disclosure is shown. As described above, the hydrogen recirculation pump 110 is configured to continuously deliver fresh hydrogen to the anode side of the fuel cell 20 in the fuel cell stack 12 of the fuel cell system 10, which in some embodiments may be a gas diffusion layer 26, such as... Figure 1C and 1D As shown.

[0054] like Figure 2AAs shown, the hydrogen recirculation pump 110 includes a pump motor assembly 120, a bearing assembly 150, and an impeller assembly 180. As described in more detail below, the various components of assemblies 120, 150, and 180 are configured to rotate about a central axis 112 of the pump 110. The pump motor assembly 120 is configured to drive the impeller 184 of the impeller assembly 180 (see figure).

[0055] 2B). Back Figure 2A The bearing assembly 150 is configured to provide rotational support for the drive shaft 131 of the pump motor 130 in the pump motor assembly 120 via the bearing seal 154. As an example, the bearing assembly 150 is axially arranged between the pump motor assembly 120 and the impeller assembly 180.

[0056] Pump motor assembly 120 includes a pump housing 122 configured to house components of pump motor 130, such as... Figure 2A As shown. The pump housing 122 may have an outer wall 124 defining a pump chamber 123, which houses at least some components of the pump motor 130. In some embodiments, the outer wall 124 may be cylindrical, such that the central axis of the cylindrical outer wall 124 extends in the same direction as the central axis 112 of the pump 110. In some embodiments, the central axis of the cylindrical outer wall 124 is collinear with the central axis 112 of the pump 110, as shown. Figure 2A As shown. As an example, the pump chamber 123 is defined by the inner surface 125 of the outer wall 124, as... Figure 2A As shown. In some embodiments, the inner surface 125 is also cylindrical. Those skilled in the art will understand that additional components or structures may be arranged on the inner surface 125 of the outer wall 124 such that the additional components or structures define the pump chamber 123.

[0057] like Figure 2A As shown, at least some components of the pump motor 130 are arranged inside and operate within the pump chamber 123. The pump motor 130 is configured to rotary drive a central drive shaft 131, which is coupled to an impeller 184 to drive the impeller 184. As an example, the pump motor 130 is an electric motor, comprising a drive shaft 131, a rotor 132 surrounding the drive shaft 131 and arranged in the pump chamber 123, and a plurality of stators 134 arranged around and spaced therefrom the rotor 132. In some embodiments, such as Figure 2A As shown, the stator 134 is arranged within the outer wall 124 and includes coils configured to electromagnetically interact with the magnets of the rotor 132, thereby selectively rotating the rotor 132. In some embodiments, the rotor 132 is cylindrical and generally conforms to the profile of the inner surface 125. Those skilled in the art will understand that an electric motor other than a motor can also be used as the pump motor 130, provided that the motor is capable of rotating the impeller 184 at the speed and torque required by the hydrogen recirculation pump 110.

[0058] The pump housing 122 may also include a support cavity 127, which is axially offset from and communicates with the pump cavity 123, such as... Figure 2A As shown. In particular, the support cavity 127 can be formed as a cylindrical or annular cavity, with one axial end opening 127O communicating with the pump cavity 123, and the opposite axial end being the end wall 127E of the cavity 127 defined by the inner surface 125 of the outer wall 124. As an example, the diameter of the support cavity 127 is smaller than the diameter of the pump cavity 123, such as... Figure 2A As shown. In some embodiments, the diameter of the support cavity 127 is approximately half the diameter of the pump cavity 123.

[0059] As described in more detail below, the first axial end 131A of the drive shaft 131 extends through the bearing assembly 150 and is coupled to the impeller 184, as shown below. Figure 2A As shown. The first axial end 131A is located within the bearing cavity 153 of the bearing housing 152 and is provided with rotational support by the first bearing seal 154. Similarly, the second axial end 131B of the drive shaft 131 extends into the support cavity 127 and is provided with rotational support by the second bearing seal 160. In some embodiments, the second bearing seal 160 may be sized such that an outer surface 161 of the bearing seal 160 contacts the inner surface 127S of the support cavity 127, as shown. Figure 2C As shown. Those skilled in the art will understand that any known type of bearing can be used as the first and second bearing seals 154, 160, as long as the bearing can provide rotational support for the drive shaft 131 during operation of the pump 110.

[0060] As an example, the pump motor assembly 120 also includes a heating assembly 140, such as Figure 2A , 2C As shown in Figure 2D. As described in more detail below, the heating assembly 140 is configured to increase the temperature of any portion of the fluid (e.g., condensate 192 described below) that leaks from the impeller 184 into and resides in the pump chamber 123. The increase in temperature causes the fluid to flow toward the impeller 184 and out of the pump chamber 123. The heating assembly 140 includes at least one heater 142, 144, 146, 147, 148, disposed on or therein the pump housing 122.

[0061] like Figure 2A As shown, the heating assembly 140 may include a plurality of heaters 142, 144, and 146 arranged at different locations outside the pump housing 122. For example, the first heater 142 may be arranged on the axial end face 129 or the second side 129 of the pump housing 122, opposite to the first side 128 of the pump housing 122 arranged on the bearing housing 152.

[0062] Additional heaters 144 and 146 may be arranged around the outer annular surface 126 of the outer wall 124 of the pump housing 122. In some embodiments, additional heaters 144 and 146 may include two heaters, but in other embodiments, more heaters may be placed around the periphery of the pump housing 122 depending on the heating requirements of the pump 110. In some embodiments, the heating assembly 140 may include only two additional heaters 144 and 146 arranged around the outer annular surface 126 (or only one heater, i.e., heater 144 or heater 146). In some embodiments, the additional heaters 144 and 146 are axially arranged on the outer annular surface 126 of the pump housing 122, located between the first side 128 and the second side 129 of the pump housing 122.

[0063] In some embodiments, the heating assembly 140 may include one or more additional heaters 147 disposed inside the pump chamber 123 to replace or supplement the heaters 142, 144, and 146 described above, such as Figure 2C As shown. In some embodiments, heater 147 may be disposed on the inner surface 125 of outer wall 124. In some embodiments, heating assembly 140 may include one or more additional heaters 148 disposed inside outer wall 124 of pump housing 122 to replace or supplement the aforementioned heaters 142, 144, 146, 147, as shown. Figure 2D As shown. In some embodiments, the heater 148 may be arranged to be spaced apart from the inner surface 125 of the outer wall 124.

[0064] Those skilled in the art will understand that any number of heaters 142, 144, 146, 147, and 148 can be used depending on the heating requirements of pump 110. For example, in some embodiments, heating assembly 140 may include heaters 142, 144, and 146 located outside pump housing 122, and heaters 147 and 148 located inside pump chamber 123 and outer wall 124. In some embodiments, heating assembly 140 may include only heaters 142, 144, and 146 located outside pump housing 122.

[0065] 144, 146 and heater 147 located within pump chamber 123. In some embodiments, heating assembly 140 may include only heaters 142, 144, 146 located outside pump housing 122 and heater 148 located within outer wall 124. In some embodiments, heating assembly 140 may include only heater 147 located within pump chamber 123 and heater 148 located within outer wall 124.

[0066] As described in more detail below, heaters 142, 144, 146, 147, and 148 are arranged at intervals relative to impeller 184 (i.e., the hydrogen process flow), as follows: Figure 2A ,2C As shown in Figure 2D. In some embodiments, heaters 142, 144, 146, 147, and 148 are arranged axially, closer to the second side 129 of the pump housing 122 and farther from the first side 128 of the pump housing 122. Thus, the condensate 192 flowing into the pump chamber 123 is heated at a position away from the impeller 184. Therefore, after the condensate 192 in the pump chamber 123 is heated, it will flow along direction 194 towards the cooler impeller 184, thereby leaving the pump chamber 123, as shown in Figure 2D. Figure 2A As shown.

[0067] Heaters 142, 144, 146, 147, and 148 can be any heater known in the art, provided that the heater can heat the condensate to a sufficiently high temperature to remove the water from the pump chamber 123. In some embodiments, heaters 142, 144, 146, 147, and 148 are electric heaters. In some embodiments, heaters 142, 144, 146, 147, and 148 are preheated coolant-based heaters. In some embodiments, heaters 142, 144, 146, 147, and 148 (particularly those disposed within the pump chamber 123) are configured to be waterproof, such that any water residing in the pump chamber 123 will not cause a short circuit or affect the performance of the heater. In some embodiments, as described in more detail below, heaters 142, 144, 146, 147, and 148 can be controlled by controller 510 based on specific operating parameters and operating conditions of pump 110.

[0068] like Figure 2A As shown, the bearing assembly 150 includes a bearing housing 152 having a first side 152A disposed on a second side 186 of the impeller housing 182 and a second side 152B disposed on a first side 128 of the pump housing 122. The bearing housing 152 may be formed as a cylinder similar to the pump housing 122. The axial length of the bearing housing 152 is shorter than the axial length of the pump housing 122, such as... Figure 2A As shown. The bearing housing 152 includes a bearing cavity 153 formed therein, which contains a first bearing seal 154. In some embodiments, the bearing cavity 153 is also formed annularly and has dimensions similar to the support cavity 127.

[0069] In some embodiments, such as Figure 2A As shown, the bearing cavity 153 includes at least one portion with a diameter equal to that of the support cavity 127. Thus, the dimensions of the first bearing seal 154 can be the same as those of the bearing seal 160. In some embodiments, the dimensions of the first bearing seal 154 can be adjusted such that an outer surface 154S of the bearing seal 154 contacts the inner surface 153S of the bearing cavity 153, as... Figure 2CAs shown. In some embodiments, the bearing cavity 153 may be stepped, such that the diameter of the first portion 153A (larger) of the stepped bearing cavity 153 is larger than the diameter of the second portion 153B (smaller) of the stepped bearing cavity 153.

[0070] like Figure 2A As shown, drive shaft 131 extends through bearing cavity 153 and is provided with rotational support by first bearing seal 154. Drive shaft 131 is coupled to impeller 184 at its terminal 131AT at a first axial end 131A. Impeller 184 is arranged in impeller cavity 183 defined within impeller housing 182 of impeller assembly 180. Impeller cavity 183 communicates with bearing cavity 153, allowing drive shaft 131 to extend through bearing cavity 153 into impeller cavity 183 and be coupled to impeller 184. Similarly, bearing cavity 153 communicates with pump cavity 123, allowing drive shaft 131 to extend from pump cavity 123 into bearing cavity 153 and then be coupled to impeller 184. Therefore, the water that is ultimately to be heated by the heating assembly 140 may leak through the impeller chamber 183 into the pump chamber 123 and enter the bearing chamber 153 (i.e. through the small gap between the bearing seal 154 and the inner surface of the bearing chamber 153), and then enter the pump chamber 123.

[0071] The impeller housing 182 can be formed into a cylindrical shape similar to the pump housing 122 and the bearing housing 152, such as... Figure 2A As shown. The axial length of the impeller housing 182 can be greater than the axial length of the bearing housing 152 and less than the axial length of the pump housing 122. The dimensions of the impeller cavity 183 defined within the impeller housing 182 can be adjusted to tightly enclose the impeller 184 therein. For example... Figure 2B As shown, the impeller housing 182 includes two openings 187 and 188, also referred to as inlet 187 and outlet 188. Inlet 187 and outlet 188 are formed in the axial end face 185 or first side 185 of the impeller housing 182, one of which (outlet 188) is as follows: Figure 2A As shown. The first side 185 can be opposite to the second side 186 of the impeller housing 182 facing the bearing housing 152.

[0072] During operation, hydrogen 190 (or other fluid, depending on the use of pump 110) can flow into impeller chamber 183, and then into impeller 184 through inlet 187. Impeller 184 can then be driven to rotate by drive shaft 131 of pump motor 130, thereby pushing hydrogen 190 out through outlet 188. Inlet 187 and outlet 188 are spaced apart on axial end face 185 of impeller housing 182.

[0073] In some embodiments, the hydrogen recirculation pump 110 is located around the fuel cell 20 and / or the fuel cell stack 12, such as... Figure 3As shown. Therefore, when the fuel cell system 10 is shut down, the hydrogen recirculation pump 110 is one of the first components in the system 10 to be cooled. With the warmer humidified hydrogen 190 present within the fuel cell system 10, the pump 110, being cooler than other components of the system 10, acts as a condenser, drawing in and retaining the condensate 192 from the humidified hydrogen 190. This condensate 192 remains in the pump chamber 123 of the pump housing 122 of the pump 110.

[0074] To prevent condensate 192 from remaining in pump chamber 123 for an extended period, the aforementioned heating assembly 140 is required, especially... Figure 2A , 2C Heaters 142, 144, 146, 147, and 148 are shown in Figure 2D. Heaters 142, 144, 146, 147, and 148 are spaced apart from the impeller 184, so that when the condensate 192 in the pump chamber 123 is heated, it flows along direction 194 towards the cooler impeller 184 and exits the pump chamber 123. Ultimately, the amount of time the condensate 192 remains in the pump chamber 123 is significantly reduced. As a result, the internal components of the pump motor 130 remain dry for a longer period, thereby extending the life of the hydrogen recirculation pump 110 and improving its durability.

[0075] As described above, heaters 142, 144, and 146 can be arranged outside the pump housing 122, inside the pump chamber 123, inside the outer wall 124 of the pump housing 122, or any combination of these locations. These arrangements of heaters 142, 144, and 146 are preferable to placing them near or above the impeller housing 182. While placing these heaters near the impeller housing 182 prevents the impeller 184 from freezing, this arrangement would drive condensate towards the cooler pump chamber 123, causing water to remain in the pump chamber 123. This would be contrary to the desired effect of the hydrogen recirculation pump 110, namely, the inability to remove water from the pump chamber 123 and / or restrict any water entry into the pump chamber 123. However, arranging heaters 142, 144, and 146 on the pump housing 122 prevents the pump impeller 184 from freezing.

[0076] According to another embodiment of the hydrogen recirculation pump 210 of this disclosure, for example Figures 4A-4C As shown. The hydrogen recirculation pump 210 is substantially similar to the hydrogen recirculation pump 110 described herein. Therefore, similar drawing numbers in the 200 series indicate common features of the hydrogen recirculation pump 210 and the hydrogen recirculation pump 110. The description of the hydrogen recirculation pump 110 is incorporated herein by reference and applies equally to the hydrogen recirculation pump 210, unless it conflicts with the specific description and drawings of the hydrogen recirculation pump 210. Any combination of components of the hydrogen recirculation pump 110 and the hydrogen recirculation pump 210 described in detail below can be used in the components of this disclosure.

[0077] The hydrogen recirculation pump 210 is basically similar in structure to the hydrogen recirculation pump 110. Specifically, it includes a pump motor assembly 210, a bearing assembly 250, and an impeller assembly 280, as shown below. Figure 4A As shown. The difference between hydrogen recirculation pump 210 and hydrogen recirculation pump 110 is at least that the bearing assembly 250 does not utilize heating assembly 140 to remove water from inside pump chamber 223, but further includes a lip seal 256 and a grease material 258 disposed within bearing chamber 253, configured to prevent any water from entering pump chamber 223. Those skilled in the art will understand that in some embodiments, a heater (e.g., the heater of heating assembly 140) may be included together with lip seal 256 and grease material 258 to add redundancy in the event that a small amount of water penetrates seal 256 and bearing seal 254 and enters pump chamber 223.

[0078] Figure 4B In more detail, a lip seal 256 (which may be an annular seal extending circumferentially around the drive shaft 231) is disposed within the bearing cavity 253, adjacent to the bearing seal 254. Specifically, the lip seal 256 may be disposed between the bearing seal 254 and the opening 259 communicating between the bearing cavity 253 and the impeller cavity 283. In some embodiments, the lip seal 256 may include a circumferential outer surface 256A contacting the inner surface 253S of the bearing cavity 253, and a circumferential inner surface 256B contacting the drive shaft 231 to form a seal. The bearing cavity 253 may be stepped, such that the diameter of the first portion 253A (larger) of the stepped bearing cavity 253 is larger than the diameter of the second portion 253B (smaller) of the stepped bearing cavity 253. Since the bearing seal 254 is disposed in the larger portion 253A, the lip seal 256 may be disposed in the smaller portion 253B.

[0079] In some embodiments, such as Figure 4C As shown, the lip seal 256 may include a lip 257 located slightly beyond the opening 259 and extending slightly radially onto the bearing housing 252. Ultimately, the axial surface 257A of the lip 257 facing the bearing housing 252 abuts against a first side 252A of the bearing housing 252, while the remainder of the body 256C of the seal 256 is disposed within the bearing cavity 253. In some embodiments, the lip 257 is axially spaced from the impeller 284. In any arrangement of the lip seal 256, as Figure 4B and 4C As shown, and in any other embodiment that a person skilled in the art may imagine, the lip seal 256 is oriented and configured to retain the grease material 258 and allow pressure to escape to the impeller assembly 280, while simultaneously blocking pressure from entering the impeller assembly 280 by sealing.

[0080] As an example, a grease material 258, used as a lubricant between the bearing seal 254 and the lip seal 258, is axially arranged between the bearing seal 254 and the lip seal 258, and simultaneously contacts both the bearing seal 254 and the lip seal 258. Figure 4B and Figure 4C As shown. The lubricating grease material 258 can also contact the drive shaft 231 and the inner surface 253S of the bearing cavity 253.

[0081] In some embodiments, the lip seal 256 is composed of a fluororubber material, and the grease material 258 is composed of a hydrogen-resistant material. In some embodiments, the grease material 258 is composed of a perfluoropolyether. These materials are well resistant to chemical damage caused by hydrogen flowing within the pump 210, particularly within the impeller chamber 283. These materials offer significant improvements in resistance to chemical damage compared to the types of materials typically used in seals and the corresponding lubricants / greases arranged in lip seals and bearing seals.

[0082] According to another embodiment of the hydrogen recirculation pump 310 of this disclosure, for example Figure 5 As shown. The hydrogen recirculation pump 310 is substantially similar to the hydrogen recirculation pumps 110 and 210 described herein. Therefore, similar drawing numbers in the 300 series indicate common features of the hydrogen recirculation pump 310 and the hydrogen recirculation pumps 110 and 210. The description of the hydrogen recirculation pumps 110 and 210 is incorporated herein by reference and applies equally to the hydrogen recirculation pump 310, unless it conflicts with the specific description and drawings of the hydrogen recirculation pump 310. Any combination of components of the hydrogen recirculation pumps 110 and 210 and the hydrogen recirculation pump 310 described in detail below can be used in the components of this disclosure.

[0083] The hydrogen recirculation pump 310 is basically similar in structure to the hydrogen recirculation pumps 110 and 210. Specifically, it includes a pump motor assembly 310, a bearing assembly 350, and an impeller assembly 380, as shown below. Figure 5 As shown. The difference between the hydrogen recirculation pump 310 and the hydrogen recirculation pumps 110 and 210 is at least that one of the heating components 340 of the pump 310 does not contain a heater, but instead uses a fluid heating circuit 342 to pump warm water 341 through the pump chamber 323. The warm water 341 heats the condensate 392 that has leaked into the pump chamber 323, thereby heating the condensate 392 and forcing it to flow towards the impeller 384, and then out of the pump chamber 323.

[0084] As an example, the heating assembly 340 may include a first conduit 344 formed in the bearing housing 352, such as Figure 5As shown. The first conduit 344 is a fluid conduit, which may be a pipe, a flexible material, or a cavity formed in the housing 352. The first conduit 344 is configured to deliver fluid, specifically warm water 341, from the inlet 345 of the first conduit 344 into the pump chamber 323. The warm water 341 may then flow through the pump chamber 323 to heat the condensate 392 residing in the pump chamber 323. In some embodiments, the warm water 341 is much hotter than the condensate 392, sufficient to heat the condensate 392 so that it flows toward the impeller 384 and exits from the pump chamber 323.

[0085] In some embodiments, the outlet 346 of the first pipe 344 communicating with the pump chamber 323 is arranged below the drive shaft 331, and its direction allows warm water 341 to flow toward the condensate 392 remaining on the bottom inner surface 323B of the pump chamber 323. The warm water 341 can be pumped through the first pipe 344 and into the pump chamber 323 via the pump 370. In some embodiments, as described in more detail below, the pump 370 can be controlled by the controller 510 based on specific operating parameters and operating conditions of the pump 110.

[0086] As an example, the heating assembly 340 may include a second conduit 347 formed in the bearing housing 352, such as Figure 5 As shown. The second conduit 347 is a fluid conduit, which may be a pipe, a flexible material, or a similar cavity formed in the housing 352. The second conduit 347 communicates with the pump chamber 323 through an opening 348 and is configured to deliver warm water 341 from the pump chamber 323 to the outlet 349 of the second conduit 347. In some embodiments, the opening 348 is arranged such that a maximum amount of heated water 392 flows through the opening 348, through the conduit 347, and exits the conduit 347 via the outlet 349.

[0087] In some embodiments, when warm water is pumped through pump chamber 323, the warm water 392 is heated as it passes through the flow path of warm water 341 and heated water 341. The warm water 341 and heated water 392 (which may be mixed together) are then pushed towards impeller 384. Figure 5 As shown. Ultimately, in some embodiments, a portion of the warm water 341 and heated water 392 will exit the pump chamber 323 through the second conduit 347, while another portion of the warm water 341 and heated water 392 will exit through the bearing chamber 353 and enter the impeller chamber 383. In some embodiments, the heating assembly 340 does not include the second conduit 347, and all the warm water 341 and heated water 392 exit the pump chamber 323 via the bearing chamber 353 and enter the impeller chamber 383. In some embodiments, in addition to the fluid heating circuit 342, the pump 310 may also include a heater, such as the heaters 142, 144, 146, 147, and 148 described above, to provide redundancy in the event of a failure of one or more components.

[0088] In some embodiments, warm water 341 may be supplied to the first conduit 344 from a water reservoir or other water source separate from the fuel cell stack 12. In some embodiments, warm water 341 may be any other fluid that does not mix with condensate 392, but is hot enough to heat condensate 392, causing it to flow toward impeller 384 and out of pump chamber 323. In some embodiments, cooling fluid 36 flowing through bipolar plates (BPPs) 28, 30 to cool the bipolar plates 28, 30 may be discharged from this flow and used as warm water 341 or a warm fluid to heat condensate 392.

[0089] According to another aspect of this disclosure, a method for recirculating fluid (e.g., condensate 192 formed from humidified hydrogen 190) in a fuel cell system (e.g., via pump 110 of the aforementioned fuel cell system 10) includes a first operation of providing a pump motor assembly, such as the aforementioned pump motor assembly 120, which includes a pump housing 122 containing a pump chamber 123 and a pump motor 130 disposed within the pump chamber 123. The method includes a second operation of arranging at least one heater, such as the aforementioned heaters 142, 144, 146, 147, 148, on or therein of the pump housing 122, spaced apart from an impeller (e.g., the aforementioned impeller 184). The method includes a third operation of rotating the impeller 184 by the pump motor 130 such that the impeller 184 pushes fluid from an inlet 187 to an outlet 188 of the impeller 184. The pump housing 122 may be arranged axially away from the impeller 184.

[0090] The method may further include a fourth operation, namely, in response to the shutdown of the fuel cell system 10, activating the at least one heater 142, 144, 146, 147, 148 via a controller 510 to increase the temperature of any portion of the fluid 192 that leaks from the impeller 184 into the pump chamber 123 and resides in the pump chamber 123. The increase in temperature causes the fluid 192 residing in the pump chamber 123 to flow towards the impeller 184 and exit the pump chamber 123. The method may further include a fifth operation, namely, based on a first operating condition of the fuel cell system 10, in response to the activation of the at least one heater 142, 144, 146, 147, 148 for a first time, deactivating the at least one heater 142, 144, 146, 147, 148 via the controller 510. In some embodiments, the first operating condition of the fuel cell system 10 means that the temperature rise caused by the at least one heater 142, 144, 146, 147, 148 causes all fluid 192 residing in the pump chamber 123 to leave the pump chamber 123.

[0091] Those skilled in the art will understand that other operating conditions and activation / deactivation times for the at least one heater can also be used. Furthermore, the method may also include pumping water through a pump chamber, such as that shown in the embodiment of pump 310 described above, based on certain operating conditions of the fuel cell system 10, which includes a fluid heating circuit 342. As a non-limiting example, the controller 510 may be configured to immediately activate the pump 370 of heaters 142, 144, 146, 147, 148 and / or fluid heating circuit 342 after the fuel cell system 10 is shut down. In some embodiments, the controller 510 may be configured to activate the pump 370 of heaters 142, 144, 146, 147, 148 and / or fluid heating circuit 342 after a predetermined amount of time following the shutdown of the fuel cell system 10. In some embodiments, the controller 510 may be configured to activate the pump 370 of heaters 142, 144, 146, 147, 148 and / or fluid heating circuit 342 in response to operating parameters detected within the recirculation pumps 110, 310.

[0092] The aforementioned controller 510, as Figure 6 As shown. Controller 510 may include a memory 511 and a processor 512. Memory 511 and processor 512 communicate with each other. Processor 512 may be embodied as any type of computing processing tool or device capable of performing the functions described herein. For example, processor 512 may be embodied as a single-core or multi-core processor, digital signal processor, microcontroller, or other processor or processing / control circuitry.

[0093] Memory 511 may be embodied as any type of volatile or non-volatile memory or data storage device capable of performing the functions described herein, and may include additional memory 513. Furthermore, controller 510 may also include additional or alternative components, such as commonly used computer components (e.g., various input / output devices, resistors, capacitors, etc.). In other embodiments, components of one or more of the illustrative controller 510 may be incorporated into another component or otherwise formed as part of another component. For example, memory 511 or a portion thereof may be incorporated into processor 512.

[0094] During operation, memory 511 can store various data and software used by controller 510 during operation, such as operating systems, applications, programs, libraries, and drivers. Memory 511 is communicatively connected to processor 512 via an I / O subsystem, which can be circuitry and / or components facilitating input / output operations on processor 512, memory 511, and other components of controller 510. In one embodiment, memory 511 may be directly connected to processor 512 (e.g., via an integrated memory controller hub). Furthermore, in some embodiments, the I / O subsystem may form part of a system-on-a-chip (SoC) and be integrated on a single integrated circuit chip (not shown) along with processor 512, memory 511, and / or other components of controller 510.

[0095] The components of communication network 516 can be configured to use any one or more communication technologies (e.g., wired, wireless, and / or powerline communication) and related protocols (e.g., Ethernet, etc.). WiMAX, 3G, 4G LTE, 5G, etc.) are used to enable communication between the aforementioned system components and devices, including but not limited to communication between the user interface 518 and heaters 142, 144, 146, 147, 148, between the user interface 518 and pump 370, between the respective heaters 142, 144, 146, 147, 148, and other communications within the fuel cell system 10 as understood by those skilled in the art.

[0096] The following aspects of this disclosure are conceivable and are not limiting:

[0097] The first aspect of this disclosure relates to a recirculation pump for a fuel cell system. The recirculation pump includes an impeller, a pump motor assembly, and at least one heater. The impeller is configured to rotate and push fluid from an inlet to an outlet. The pump motor assembly includes a pump housing and a pump motor, with a pump chamber within the pump housing and the pump motor disposed within the pump chamber. The pump motor is configured to drive the impeller, and the pump housing is disposed axially away from the impeller. The at least one heater is disposed on or within the pump housing and spaced apart from the impeller. The at least one heater is configured to increase the temperature of any portion of the fluid leaking from the impeller into the pump chamber and residing in the pump chamber. The increase in temperature causes the fluid residing in the pump chamber to flow toward the impeller and exit the pump chamber.

[0098] A second aspect of this disclosure relates to a recirculation pump for a fuel cell system. The recirculation pump includes an impeller and a bearing assembly. The impeller includes a drive shaft coupled to the center of the impeller and configured to rotatably push fluid from the impeller inlet to the impeller outlet. The bearing assembly is arranged axially away from the impeller and includes a bearing housing and a bearing seal. The bearing housing has a bearing cavity, and the bearing seal is disposed within the bearing cavity. The drive shaft extends from the impeller through the bearing cavity, is disposed within the bearing seal, and is provided with rotational support by the bearing seal. The bearing assembly also includes a lip seal disposed within the bearing cavity, and a grease material disposed within the bearing cavity between the lip seal and the bearing seal.

[0099] A third aspect of this disclosure relates to a method for circulating fluid in a fuel cell system. The method includes providing a pump motor assembly comprising a pump housing containing a pump chamber, and a pump motor disposed within the pump chamber; at least one heater disposed on or therein of the pump housing and spaced apart from an impeller; and rotating the impeller by the pump motor such that the impeller pushes fluid from an inlet to an outlet. The pump housing is disposed axially away from the impeller. The method further includes activating the at least one heater via a controller in response to the fuel cell system being shut down to increase the temperature of any portion of the fluid leaking from the impeller into the pump chamber and residing in the pump chamber. The temperature increase causes the fluid residing in the pump chamber to flow toward the impeller and exit the pump chamber. The method further includes deactivating the at least one heater via the controller in response to a first time amount that the at least one heater has been activated, based on a first operating condition of the fuel cell system.

[0100] In a first aspect of this disclosure, the recirculation pump may further include an impeller assembly. The impeller assembly may include an impeller housing containing an impeller cavity and having an inlet and an outlet. The inlet and outlet are spaced apart on a first side of the impeller housing. Each inlet and outlet may communicate with the impeller cavity. The impeller assembly may further include an impeller disposed in the impeller cavity and configured to push fluid entering the impeller cavity from the inlet to the outlet, such that the fluid exits the impeller housing through the outlet.

[0101] In a first aspect of this disclosure, the pump housing may be disposed on a second side of the impeller housing, opposite to the first side. The first heater of the at least one heater may be arranged on the second side of the pump housing, opposite to the first side of the pump housing facing the impeller housing. In a first aspect of this disclosure, the second heater of the at least one heater may be axially arranged on the outer surface of the pump housing between the first and second sides. In a first aspect of this disclosure, the axial position of the second heater may be closer to the second side of the pump housing and farther from the first side. In a first aspect of this disclosure, at least one additional heater and the second heater of the at least one heater may be axially arranged on the outer surface of the pump housing between the first and second sides.

[0102] In a first aspect of this disclosure, a pump motor can be coupled to an impeller via a drive shaft, and the pump motor can drive the rotation of both the drive shaft and the impeller. In a first aspect of this disclosure, the recirculation pump may further include a bearing assembly axially arranged between the pump motor assembly and the impeller assembly. The bearing assembly may include a bearing housing, a first side of which is disposed on a second side of the impeller housing, opposite to the first side of the impeller housing, and defines a bearing cavity therein. The bearing assembly may further include a bearing seal disposed within the bearing cavity. The drive shaft extends from the pump motor through the bearing cavity to the impeller. The drive shaft may be disposed within the bearing seal and provided with rotational support by the bearing seal. In a first aspect of this disclosure, the bearing assembly may further include a lip seal disposed within the bearing cavity between the bearing seal and the impeller, and a grease material disposed within the bearing cavity between the lip seal and the bearing seal. The grease material may be disposed adjacent to the bearing seal and distributed around the circumferential outer surface of the drive shaft. In a first aspect of this disclosure, the lip seal can be arranged to retain grease material adjacent to the bearing seal, allowing pressure to escape from the pump chamber and forming a seal to block pressure from the impeller chamber. In a first aspect of this disclosure, the lip seal can be made of fluororubber, and the grease material can be made of hydrogen-resistant material. In a first aspect of this disclosure, the grease material can be made of perfluoropolyether.

[0103] In a second aspect of this disclosure, the lip seal can be arranged to retain grease material between the lip seal and the bearing seal so that it can escape into the pressure pump chamber and form a seal to block pressure from the impeller chamber.

[0104] In a second aspect of this disclosure, the lip seal may be composed of a fluororubber material, and the grease material may be composed of a hydrogen-resistant material. In another second aspect of this disclosure, the grease material may be composed of a perfluoropolyether.

[0105] In a second aspect of this disclosure, the recirculation pump may further include a pump motor assembly and at least one heater. The pump motor assembly may include a pump housing and a pump motor, with a pump chamber within the pump housing and the pump motor disposed within the pump chamber. The drive shaft may be coupled to the pump motor such that the pump motor is configured to drive an impeller. The pump housing may be arranged adjacent to the bearing housing on the side opposite the impeller. The at least one heater may be located on or within the pump housing and spaced apart from the bearing housing. The at least one heater may be configured to increase the temperature of any portion of the fluid that leaks from the impeller through the bearing chamber into the pump chamber and resides in the pump chamber. The temperature increase may cause the fluid residing in the pump chamber to flow toward the impeller and exit the pump chamber. In a second aspect of this disclosure, a first heater of the at least one heater may be disposed on a second side of the pump housing, opposite to a first side of the pump housing facing the bearing housing. A second heater of the at least one heater may be axially disposed on an outer surface of the pump housing between the first and second sides of the pump housing.

[0106] In a third aspect of this disclosure, the first operating condition may refer to a temperature rise caused by the at least one heater causing all fluid residing in the pump chamber to leave the pump chamber. In another third aspect of this disclosure, the method may further include arranging an impeller comprising an impeller housing having a first side and a second side opposite to the first side; arranging the first side of the pump housing on the second side of the impeller housing; and arranging the first heater of the at least one heater on the second side of the pump housing, opposite to the first side of the pump housing facing the impeller housing.

[0107] Although this disclosure has been described in detail in the accompanying drawings and foregoing, such description and illustration should be regarded as exemplary rather than restrictive, and should be understood as merely illustrating and describing illustrative embodiments, and all changes and modifications conforming to this disclosure should be protected.

[0108] Several advantages of this disclosure arise from the various features of the methods, apparatus, and systems described herein. It should be noted that alternative embodiments of the methods, apparatus, and systems of this disclosure may not include all the features described, but will still benefit from at least some of the advantages of these features. Those skilled in the art can readily devise their own implementations of methods, apparatus, and systems that incorporate one or more features of the invention and are within the spirit and scope of this disclosure as defined in the appended claims.

[0109] Features illustrated or described in connection with an exemplary embodiment may be combined with any other feature or element of any other embodiment described herein. Such modifications and variations are intended to be included within the scope of this disclosure. Furthermore, those skilled in the art will recognize that terms well-known to them may be used interchangeably herein.

[0110] The above description of the embodiments is detailed enough to enable those skilled in the art to implement the claims, and it should be understood that logical, mechanical, and electrical changes can be made without departing from the spirit and scope of the claims. Therefore, the detailed description should not be considered limiting.

[0111] As used herein, elements or steps listed in the singular and beginning with the words “a” or “an” should be understood to not exclude the plural form of the elements or steps unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the subject matter herein are not intended to exclude the existence of other embodiments that also include the listed features. Specified numerical ranges of units, measurements, and / or values ​​include, substantially consist of, all numerical values, units, measurements, and / or ranges, including or within these ranges and / or endpoints, whether or not such numerical values, units, measurements, and / or ranges are expressly specified in this disclosure.

[0112] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” etc., as used herein do not indicate any order or importance, but are used to distinguish one element from another. The term “or” means including and refers to any or all of the listed items. Furthermore, the terms “connection” and “linkage” are not limited to physical or mechanical connections or linkages, but may also include direct or indirect electrical connections or linkages.

[0113] Furthermore, unless explicitly stated otherwise, embodiments that "comprising," "include," or "have" one or more elements having a specific property may include other such elements that do not have that property. The terms "comprising" or "comprises" refer to compositions, compounds, formulations, or methods that include, but do not exclude, other elements, components, and / or method steps. The term "comprising" may also refer to embodiments of compositions, compounds, formulations, or methods in this disclosure that include, but do not exclude, other elements, components, and / or method steps.

[0114] The phrase "consisting of" or "consists of" refers to a mixture, composition, formulation, or method that excludes any other element, component, or method step. The phrase "consisting of" also refers to a compound, composition, formulation, or method that excludes any additional element, component, or method step in this disclosure.

[0115] The phrase "consisting essentially of" or "consists essentially of" refers to a composition, compound, formulation, or method that includes other elements, components, or method steps that do not materially affect the characteristics of the composition, compound, formulation, or method. The phrase "consisting essentially of" also refers to a composition, compound, formulation, or method disclosed herein that includes other elements, components, or method steps that do not materially affect the characteristics of the composition, compound, formulation, or method.

[0116] The approximate language used in this specification and claims may be used to modify any quantitative expression that allows for variation without altering its underlying function. Therefore, numerical values ​​modified by one or more terms (such as "about" and "substantially") should not be limited to specified exact values. In some cases, approximate language may correspond to the precision of the instrument used to measure the numerical value. In this specification and claims, scope limitations may be combined and / or interchanged. Unless the context or language otherwise indicates, such scope is identified and includes all subscopes contained therein.

[0117] As used herein, the terms “may” and “may be” indicate a possibility of occurring in a range of situations; possessing a specific attribute, characteristic, or function; and / or defining one verb by expressing one or more capabilities or possibilities associated with the defining verb. Therefore, the use of “may” and “may be” indicates that the modified terms are clearly appropriate, capable, or suitable for the indicated capability, function, or usage, while taking into account that in some cases the modified terms may sometimes be inappropriate, incapable, or unsuitable.

[0118] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used alone, together, or in combination with each other. Furthermore, many modifications can be made to adapt a particular situation or material to the teachings of the subject matter described herein without departing from its scope. Although the dimensions and types of the materials described herein are intended to define the parameters of the disclosed subject matter, they are by no means limiting but rather exemplary embodiments. Many other embodiments will become apparent to those skilled in the art upon review of the foregoing description. Therefore, the scope of the subject matter described herein should be determined by reference to the appended claims and the full scope of equivalents to which such claims are entitled.

[0119] This written specification uses examples to disclose several embodiments (including best modes) of the subject matter described herein, and also enables those skilled in the art to practice embodiments of the disclosed subject matter, including making and using the apparatus or system and performing methods. The patentable scope of the subject matter described herein is defined by the claims, and may include other examples that would occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if their structural elements are not indistinguishable from the literal language of the claims, or if they comprise equivalent structural elements that are not substantially different from the literal language of the claims.

[0120] Although only certain features of the invention have been illustrated and described herein, many modifications and variations will be apparent to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and variations that fall within the true spirit and scope of the invention.

Claims

1. A recirculation pump for a fuel cell system, comprising: An impeller, configured to rotate and push fluid from the inlet to the outlet; A pump motor assembly comprising a pump housing having a pump chamber therein and a pump motor disposed within the pump chamber and configured to drive the impeller, the pump housing being arranged axially away from the impeller; and At least one heater is disposed on or in the pump housing and spaced apart from the impeller, the at least one heater being configured to increase the temperature of any portion of the fluid leaking from the impeller into the pump chamber and residing in the pump chamber, wherein the increase in temperature causes the fluid residing in the pump chamber to flow toward the impeller and leave the pump chamber.

2. The recirculation pump according to claim 1, further comprising: An impeller assembly includes an impeller housing having an impeller cavity therein and having an inlet and an outlet, the inlet and the outlet being spaced apart on a first side of the impeller housing, each of the inlet and the outlet opening into the impeller cavity, the impeller assembly further including an impeller disposed in the impeller cavity and configured to push fluid entering the impeller cavity from the inlet to the outlet, such that the fluid exits the impeller housing through the outlet.

3. The recirculation pump according to claim 2, wherein, The pump housing is disposed on a second side of the impeller housing opposite to the first side, and wherein a first heater of the at least one heater is disposed on the second side of the pump housing opposite to the first side of the pump housing facing the impeller housing.

4. The recirculation pump according to claim 3, wherein, The second heater of the at least one heater is arranged axially between the first and second sides of the pump housing on the outer surface of the pump housing.

5. The recirculation pump according to claim 4, wherein, Compared to the first side of the pump housing, the second heater is located axially closer to the second side of the pump housing.

6. The recirculation pump according to claim 4, wherein, At least one additional heater and the second heater are arranged axially on the outer surface of the pump housing between the first and second sides of the pump housing.

7. The recirculation pump according to claim 2, wherein, The pump motor is connected to the impeller via a drive shaft, and the pump motor drives the rotation of the drive shaft and the rotation of the impeller.

8. The recirculation pump according to claim 7, further comprising: A bearing assembly, axially disposed between the pump motor assembly and the impeller assembly, the bearing assembly including a bearing housing having a first side disposed on a second side of the impeller housing opposite a first side of the impeller housing and having a bearing cavity defined therein, the bearing assembly further including a bearing seal disposed in the bearing cavity. The drive shaft extends from the pump motor through the bearing cavity and extends to the impeller, wherein the drive shaft is arranged within the bearing seal and is rotatably supported by the bearing seal.

9. The recirculation pump according to claim 8, wherein, The bearing assembly further includes a lip seal disposed within the bearing cavity between the bearing seal and the impeller, and a grease material disposed within the bearing cavity between the lip seal and the bearing seal, the grease material being arranged adjacent to and abutting the bearing seal, and arranged around the circumferential outer surface of the drive shaft.

10. The recirculation pump according to claim 9, wherein, The lip seal is arranged to hold the grease material in place against the bearing seal so as to allow pressure to escape from the pump chamber and to provide a seal against pressure from the impeller chamber.

11. The recirculation pump according to claim 9, wherein, The lip seal comprises a fluorinated elastomer material, and the grease material comprises a hydrogen-resistant material.

12. The recirculation pump according to claim 11, wherein, The grease material includes perfluoropolyether.

13. The recirculation pump according to claim 1, wherein, The at least one heater is disposed on the outer surface of the pump housing.

14. The recirculation pump of claim 13, further comprising: An impeller assembly includes an impeller housing having an inlet and an outlet, the inlet and the outlet being spaced apart on a first side of the impeller housing. The at least one heater is a first heater, and the pump housing is disposed on a second side of the impeller housing opposite to the first side, and the second heater of the at least one heater is disposed on an axial end face of the pump housing opposite to the first side of the pump housing facing the impeller housing.

15. The recirculation pump according to claim 14, wherein, The outer surface of the pump housing extends axially between the first side and the axial end face of the pump housing.

16. A method for recirculating fluid in a fuel cell system, comprising: A pump motor assembly is provided, the pump motor assembly including a pump housing having a pump chamber therein and a pump motor disposed in the pump chamber; At least one heater is arranged on or in the pump housing and spaced apart from the impeller; The impeller is rotated by the pump motor, causing the impeller to push fluid from the impeller inlet to the impeller outlet, wherein the pump housing is arranged axially away from the impeller. In response to the fuel cell system being shut down, the at least one heater is activated by the controller, and the temperature of any portion of the fluid leaking from the impeller into the pump chamber and residing in the pump chamber is increased, wherein the increased temperature causes the fluid residing in the pump chamber to flow toward the impeller and leave the pump chamber; and In response to the at least one heater having operated for a first time based on the first operating conditions of the fuel cell system, the at least one heater is deactivated by the controller.

17. The method according to claim 16, wherein, The first operating condition is when all fluid residing in the pump chamber has left the pump chamber by the temperature increase caused by the at least one heater.

18. The method according to claim 16, wherein, The at least one heater is a first heater, and the arrangement step includes arranging the at least one heater on the outer surface of the pump housing.

19. The method of claim 18, further comprising: The impeller is arranged in an impeller housing having a first side and a second side opposite to the first side; The first side of the pump housing is arranged on the second side of the impeller housing; and The second heater is arranged on the axial end face of the pump housing opposite to the first side of the pump housing facing the impeller housing.

20. The method according to claim 19, wherein, Compared to the first side of the pump housing, the first heater is located axially closer to the axial end face of the pump housing.

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