Patent Application
20230402617
The present disclosure generally relates to a fuel cell stack assembly, in particular preventing permeation of fluid within components of the fuel cell stack assembly.
A fuel cell is a multi-component assembly that often comprises a membrane electrode assembly (MEA) at the center, a gas diffusion layer (GDL) on either side of the membrane electrode assembly (MEA), and a bipolar plate (BPP) on either side of the gas diffusion layer (GDL). In many bipolar plate designs, the anode and cathode sides of the bipolar plate are formed of a polymer composite material. Such polymer composite materials typically yield porous bipolar plates, which may allow coolant flowing within the bipolar plate to permeate through the anode and cathode sides and into the gas diffusion layers.
Specific types of coolant interacting with the gas diffusion layers may damage the fuel cell stack. These specific types of coolants may be particularly harmful to gas diffusion layers. Accordingly, it would be advantageous to provide a bipolar plate for a fuel cell and/or fuel cell stack that prevents permeation of fluid (e.g., coolant) through the bipolar plate and into the gas diffusion layers or other components of the fuel cell stack.
According to a first aspect of the present disclosure, a bipolar plate assembly for a fuel cell includes a cathode sheet assembly and an anode sheet assembly. The cathode sheet assembly includes a first cathode sheet, a second cathode sheet, and a first divider sheet. The first divider sheet is arranged between the first cathode sheet and the second cathode sheet. The first cathode sheet includes a first cathode sheet outer surface opposite the first divider sheet configured to interact with a cathode gas diffusion layer of the fuel cell, and the second cathode sheet includes a second cathode sheet outer surface opposite the first divider sheet.
The second cathode sheet outer surface is arranged on the second divider sheet such that the anode sheet assembly and the cathode sheet assembly form the bipolar plate. The second cathode sheet includes at least one passage formed therein, and the at least one passage includes a fluid flowing therein. The first divider sheet is configured to prevent the fluid from permeating through the first cathode sheet and reaching the first cathode sheet outer surface such that the fluid cannot interact with the cathode gas diffusion layer. The second divider sheet is configured to prevent the fluid from permeating through the anode sheet and reaching the anode sheet outer surface such that the fluid cannot interact with the anode gas diffusion layer.
In some embodiments, the anode sheet, the first cathode sheet, and the second cathode sheet are formed of a polymer composite material. In some embodiments, the first divider sheet and the second divider sheet are formed of a metallic material. In some embodiments, the bipolar plate assembly further includes a polymer composite coating arranged between and contacting the anode sheet and the second divider sheet, arranged between and contacting the first cathode sheet and the first divider sheet, or arranged between and contacting the second cathode sheet and the first divider sheet. In some embodiments, the fluid is a coolant fluid including ethylene glycol.
In some embodiments, the at least one passage includes a plurality of elongated grooves formed on the second cathode sheet outer surface of the second cathode sheet and opening outwardly away from the second cathode sheet outer surface. The second divider sheet of the anode sheet assembly is arranged on the second cathode sheet outer surface such that the second divider sheet encloses the plurality of elongated grooves. The fluid flowing through the plurality of elongated grooves is a coolant fluid. In some embodiments, a bottom surface of each of the plurality of elongated grooves is spaced apart from the first divider sheet of the cathode sheet assembly.
In some embodiments, the anode sheet, the first cathode sheet, the second cathode sheet, the first divider sheet, and the second divider sheet are generally planar and parallel with each other. In some embodiments, each of the first divider sheet and the second divider sheet has a length that is longer than a length of each of the anode sheet, the first cathode sheet, and the second cathode sheet such that at least a portion of a first end of each of the first divider sheet and the second divider sheet extends beyond a corresponding first end of each of the anode sheet, the first cathode sheet, and the second cathode sheet, and such that at least a portion of a second end of each of the first divider sheet and the second divider sheet opposite the first end extends beyond a corresponding second end of each of the anode sheet, the first cathode sheet, and the second cathode sheet.
In some embodiments, the portion of the first end of the first divider sheet that extends beyond the corresponding first end of the anode sheet, the first cathode sheet, and the second cathode sheet is welded to the portion of the first end of the second divider sheet that extends beyond the corresponding first end of the anode sheet, the first cathode sheet, and the second cathode sheet. The portion of the second end of the first divider sheet that extends beyond the corresponding second end of the anode sheet, the first cathode sheet, and the second cathode sheet is welded to the portion of the second end of the second divider sheet that extends beyond the corresponding second end of the anode sheet, the first cathode sheet, and the second cathode sheet.
According to a further aspect of the present disclosure, a bipolar plate assembly for a fuel cell includes a first bipolar sheet assembly and a second bipolar sheet assembly. The first bipolar sheet assembly including a first bipolar sheet and a first divider sheet. The first bipolar sheet includes a first bipolar sheet outer surface and a first bipolar sheet inner surface opposite the first bipolar sheet outer surface. The first divider sheet is arranged on the first bipolar sheet inner surface. The second bipolar sheet assembly includes a second bipolar sheet, a third bipolar sheet, and a second divider sheet. The second divider sheet is arranged between the second bipolar sheet and the third bipolar sheet. The second bipolar sheet includes a second bipolar sheet outer surface opposite the second divider sheet. The third bipolar sheet includes a third bipolar sheet inner surface opposite the second divider sheet. The third bipolar sheet inner surface is arranged on the first divider sheet such that the first bipolar sheet assembly and the second bipolar sheet assembly form the bipolar plate. The third bipolar sheet includes at least one passage formed therein.
The at least one passage includes a fluid flowing therein. The first divider sheet is configured to prevent the fluid from permeating through the first bipolar sheet and reaching the first bipolar sheet outer surface, and the second divider sheet is configured to prevent the fluid from permeating through the second bipolar sheet and reaching the second bipolar sheet outer surface.
In some embodiments, the first bipolar sheet, the second bipolar sheet, and the third bipolar sheet are formed of a polymer composite material, and wherein the first divider sheet and the second divider sheet are formed of a metallic material. In some embodiments, the bipolar plate assembly further includes a polymer composite coating arranged between and contacting the first bipolar sheet and the first divider sheet, arranged between and contacting the second bipolar sheet and the second divider sheet, and arranged between and contacting the third bipolar sheet and the second divider sheet.
In some embodiments, the at least one passage includes a plurality of elongated grooves formed on the third bipolar sheet inner surface of the third bipolar sheet and opening outwardly away from the third bipolar sheet inner surface. The first divider sheet of the first bipolar sheet assembly is arranged on the third bipolar sheet inner surface such that the first divider sheet encloses the plurality of elongated grooves. The fluid flowing through the plurality of elongated grooves is a coolant fluid. In some embodiments, a bottom surface of each of the plurality of elongated grooves is spaced apart from the second divider sheet of the second bipolar sheet assembly.
In some embodiments, the first bipolar sheet, the second bipolar sheet, the third bipolar sheet, the first divider sheet, and the second divider sheet are generally planar, and the first bipolar sheet, the second bipolar sheet, the third bipolar sheet, the first divider sheet, and the second divider sheet are generally parallel with each other.
In some embodiments, each of the first divider sheet and the second divider sheet has a length that is longer than a length of each of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet such that at least a portion of a first end of each of the first divider sheet and the second divider sheet extends beyond a corresponding first end of each of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet, and such that at least a portion of a second end of each of the first divider sheet and the second divider sheet opposite the first end extends beyond a corresponding second end of each of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet.
In some embodiments, the portion of the first end of the first divider sheet that extends beyond the corresponding first end of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet is welded to the portion of the first end of the second divider sheet that extends beyond the corresponding first end of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet. The portion of the second end of the first divider sheet that extends beyond the corresponding second end of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet is welded to the portion of the second end of the second divider sheet that extends beyond the corresponding second end of the first bipolar sheet, the second bipolar sheet, the third bipolar sheet.
A method of forming a bipolar plate assembly of a fuel cell according to a further aspect of the present disclosure includes providing a first cathode sheet, a second cathode sheet, and a first divider sheet, the first cathode sheet including a first cathode sheet outer surface opposite the first divider sheet configured to interact with a cathode gas diffusion layer of the fuel cell, the second cathode sheet including a second cathode sheet outer surface opposite the first divider sheet. The method further includes arranging the first divider sheet between the first cathode sheet and the second cathode sheet, and providing an anode sheet and a second divider sheet, the anode sheet including an anode sheet outer surface and an anode sheet inner surface opposite the anode sheet outer surface, the anode sheet outer surface being configured to interact with an anode gas diffusion layer of the fuel cell. The method further includes arranging the second divider sheet on the anode sheet inner surface.
The second cathode sheet outer surface is arranged on the second divider sheet such that the anode sheet assembly and the cathode sheet assembly form the bipolar plate, the second cathode sheet including at least one passage formed therein. The at least one passage includes a fluid flowing therein. The first divider sheet is configured to prevent the fluid from permeating through the first cathode sheet and reaching the first cathode sheet outer surface such that the fluid cannot interact with the cathode gas diffusion layer. The second divider sheet is configured to prevent the fluid from permeating through the anode sheet and reaching the anode sheet outer surface such that the fluid cannot interact with the anode gas diffusion layer.
In some embodiments, the arranging of the second divider sheet on the anode sheet inner surface includes adhering the second divider sheet on the anode sheet inner surface. Prior to adhering the second divider sheet on the anode sheet inner surface, the method further includes sanding a side of the second divider sheet to be arranged on the anode sheet inner surface to create surface roughness and increase adhesion between the second divider sheet on the anode sheet inner surface.
This disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
As shown in
Each fuel cell module 114 may include a plurality of fuel cell stacks 112 and/or a plurality of fuel cells 120. The fuel cell module 114 may also include a suitable combination of associated structural elements, mechanical systems, hardware, firmware, and/or software that is employed to support the function and operation of the fuel cell module 114. Such items include, without limitation, piping, sensors, regulators, current collectors, seals, and insulators.
The fuel cells 120 in the fuel cell stacks 112 may be stacked together to multiply and increase the voltage output of a single fuel cell stack 112. The number of fuel cell stacks 112 in a fuel cell system 100 can vary depending on the amount of power required to operate the fuel cell system 100 and meet the power need of any load. The number of fuel cells 120 in a fuel cell stack 112 can vary depending on the amount of power required to operate the fuel cell system 100 including the fuel cell stacks 112.
The number of fuel cells 120 in each fuel cell stack 112 or fuel cell system 100 can be any number. For example, the number of fuel cells 120 in each fuel cell stack 112 may range from about 100 fuel cells to about 1000 fuel cells, including any specific number or range of number of fuel cells 120 comprised therein (e.g., about 1200 to about 800). In an embodiment, the fuel cell system 100 may include about 120 to about 1000 fuel cells stacks 112, including any specific number or range of number of fuel cell stacks 112 comprised therein (e.g., about 1200 to about 800). The fuel cells 120 in the fuel cell stacks 112 within the fuel cell module 114 may be oriented in any direction to optimize the operational efficiency and functionality of the fuel cell system 100.
The fuel cells 120 in the fuel cell stacks 112 may be any type of fuel cell 120. The fuel cell 120 may 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 cells 120 may be a polymer electrolyte membrane or proton exchange membrane (PEM) fuel cell or a solid oxide fuel cell (SOFC).
In an embodiment shown in
The bipolar plates (BPP) 128, 130 are responsible for the transport of reactants, such as fuel 132 (e.g., hydrogen) or oxidant 134 (e.g., oxygen, air), and cooling fluid 136 (e.g., coolant and/or water) in a fuel cell 120, as shown in
The bipolar plates (BPP) 128, 130 may each be formed to have reactant flow fields 142, 144 formed on opposing outer surfaces of the bipolar plate (BPP) 128, 130, and formed to have coolant flow fields 152 located within the bipolar plate (BPP) 128, 130, as shown in
The fuel cell system 100 described herein, may be used in stationary and/or immovable power system, such as industrial applications and power generation plants. The fuel cell system 100 may also be implemented in conjunction with an air delivery system 118. Additionally, the fuel cell system 100 may also be implemented in conjunction with a hydrogen delivery system and/or a source of hydrogen 19 such as a pressurized tank, including a gaseous pressurized tank, cryogenic liquid storage tank, chemical storage, physical storage, stationary storage, an electrolysis system or an electrolyzer. In one embodiment, the fuel cell system 100 is connected and/or attached in series or parallel to a hydrogen delivery system and/or a source of hydrogen 19, such as one or more hydrogen delivery systems and/or sources of hydrogen 19 in the BOP 16 (see
In some embodiments, the fuel cell system 100 may include an on/off valve 100XV1, a pressure transducer 100PT1, a mechanical regulator 100REG, and a venturi 100VEN arranged in operable communication with each other and downstream of the hydrogen delivery system and/or source of hydrogen 119. The pressure transducer 100PT1 may be arranged between the on/off valve 100XV1 and the mechanical regulator 100REG. In some embodiments, a proportional control valve may be utilized instead of a mechanical regulator 100REG. In some embodiments, a second pressure transducer 100PT2 is arranged downstream of the venturi 100VEN, which is downstream of the mechanical regulator 100REG.
In some embodiments, the fuel cell system 100 may further include a recirculation pump 100REC downstream of the stack 112 and operably connected to the venturi 100VEN. The fuel cell system 100 may also include a further on/off valve 100XV2 downstream of the stack 112, and a pressure transfer valve 100PSV.
The present fuel cell system 100 may also be comprised in mobile applications. In an exemplary embodiment, the fuel cell system 100 is in a vehicle and/or a powertrain 200. A vehicle 200 comprising the present fuel cell system 100 may be an automobile, a pass car, a bus, a truck, a train, a locomotive, an aircraft, a light duty vehicle, a medium duty vehicle, or a heavy-duty vehicle. Type of vehicles 200 can also include, but are not limited to commercial vehicles and engines, trains, trolleys, trams, planes, buses, ships, boats, and other known vehicles, as well as other machinery and/or manufacturing devices, equipment, installations, among others.
The vehicle and/or a powertrain 200 may be used on roadways, highways, railways, airways, and/or waterways. The vehicle 200 may be used in applications including but not limited to off highway transit, bobtails, and/or mining equipment. For example, an exemplary embodiment of mining equipment vehicle 200 is a mining truck or a mine haul truck.
In addition, it may be appreciated by a person of ordinary skill in the art that the fuel cell system 100, fuel cell stack 112, and/or fuel cell 120 described in the present disclosure may be substituted for any electrochemical system, such as an electrolysis system (e.g., an electrolyzer), an electrolyzer stack, and/or an electrolyzer cell (EC), respectively. As such, in some embodiments, the features and aspects described and taught in the present disclosure regarding the fuel cell system 100, stack 112, or cell 120 also relate to an electrolyzer, an electrolyzer stack, and/or an electrolyzer cell (EC). In further embodiments, the features and aspects described or taught in the present disclosure do not relate, and are therefore distinguishable from, those of an electrolyzer, an electrolyzer stack, and/or an electrolyzer cell (EC).
The present disclosure is specifically directed to one or more bipolar plates 10 for a fuel cell 120 and/or fuel cell stack 112 configured to be utilized as the bipolar plates 128, 130 associated with the exemplary fuel cell 120 and/or fuel cell stack 112 shown in
According to a first aspect of the present disclosure, a repeating fuel cell assembly unit 150 of a fuel cell 120 is shown in
The cross-sectional area of the fuel cell 120 and/or fuel cell stack 112 may determine the current operating range of the fuel cell 120 and/or fuel cell stack 112. In some embodiments, the product of the number of fuel cells 120 comprised in a fuel cell stack 112 and the area of each fuel cell 120 may determine and/or indicate an overall power generation rating of the fuel cell stack 112. The membrane electrode assembly 122 and the gas diffusion layer 124, 126 may also impact the power generation rating and durability of the fuel cell stack.
In some embodiments, the bipolar plates 10, 128, 130 may provide mechanical support to prevent the fuel cell 120 and/or fuel cell stack 112 from bursting when pressurized. In other embodiments, the bipolar plate 10, 128, 130 may provide rigidity for compressing and/or sealing the fuel cell 120, such as to provide an inherent and/or intrinsic seal of the fuel cell 120. In some other embodiments, one or more external seals may be comprised by the fuel cell 120. These sealing mechanisms isolate the oxidant 134, fuel 132, and/or cooling fluids (e.g., coolant or water) 136 to their respective flow field pathways 142, 144, 152 and/or prevent their leakage externally.
The oxidant flow fields 142, the fuel flow fields 144, and the cooling fluid (e.g., coolant and/or water) flow fields 152 may be in any configuration, such as parallel or non-parallel to each other. Specifically, see
In some embodiments, each fuel cell 120 and/or fuel cell stack 112 may have one or more, many, multiple, or a plurality (two or more) of the oxidant flow fields 142, the fuel flow fields 144, and/or the cooling fluid (e.g., coolant) flow fields 152, as well as a plurality of bipolar plates 10, 128, 130, as shown in
The general design of an exemplary bipolar plate assembly 10 that may be utilized as the bipolar plate 128, 130 in the fuel cell 120 is shown in
The bipolar plate assembly 10 further includes an active area 19 on each side of the plate assembly 10, as shown in
Similarly, the active area 19 on the side of the bipolar plate assembly 10 facing the anode gas diffusion layer 126 may include a plurality of grooves that define the channels or flow fields (see also
A bipolar plate assembly 10 configured to be utilized as the bipolar plates 128, 130 in the fuel cell 120 or fuel cell stack 112 is shown in
As will be described in greater detail below, the cathode and anode sheet assemblies 20, 30 each include a divider sheet 40, 44 arranged therein, as shown in
The cathode sheet assembly 20 and the anode sheet assembly 30 may be comprised of formed sheets of material bonded or welded adjacent to each other. By way of non-limiting examples, the cathode sheet assembly 20 and the anode sheet assembly 30 may each be formed of one, two, three, or more sheets. Illustratively, the cathode sheet assembly 20 is comprised of a first cathode sheet 21, a second cathode sheet 22, and a divider sheet 40 arranged between the sheets 21, 22, as shown in
The cathode and anode sheets 21, 22, 32 may be formed of a polymer composite material. In some embodiments, the polymer composite material may be a mixture of thermoset polymer matrix and carbon filler. The carbon filler may include, but is not limited to, graphite, carbon fiber, and carbon black. In some embodiments, the polymer composite material may include approximately 25% to 35% of thermoset polymer matrix and 65% to 75% of carbon filler, including any specific or range of percentages comprised therein. In an exemplary embodiment, the cathode and anode sheets 21, 22, 32 are formed of approximately 30% thermoset polymer matrix and 70% carbon filler. In other embodiments, the cathode and anode sheets 21, 22, 32 may include different percentages of thermoset polymer matrix and carbon filler, including any percentage or range of percentages described herein.
In some embodiments, the thermoset polymer matrix may be liquid resin. Because metal is utilized in the divider sheets 40, 44 and thus provides high levels of conductivity, a higher ratio of liquid resin to carbon filler may be utilized than is typically used in polymer composite materials for cathode and anode sheets. Higher levels of liquid resin provide improved flow of polymer composite material in the cathode sheets 21 and 22, as well as anode sheet 32.
The divider sheets 40, 44 may be formed of a metallic material. As will be described in greater detail below, the polymer composite material of the cathode and anode sheets 21, 22, 32 are typically porous. The porosity of the sheets 21, 22, 32 may allow the coolant 90 flowing within the bipolar plate assembly 10 to permeate through the cathode and anode sheets 21, 22, 32 and into the gas diffusion layers 124, 126 arranged on outer sides of the cathode and anode sheet assemblies 20, 30, as shown in
In some embodiments, the metallic material may include, but is not limited to, aluminum, titanium, silver, copper, stainless steel, pyrolytic graphite sheet metal, or combinations thereof. Specific examples of metals comprised in the metallic material may include, but are not limited to, austenitic stainless steel (304L, 316L, 904L, 310S), ferritic stainless steel (430, 441, 444, Crofer), titanium (Grade 1, Grade 2), or aluminum (1000 series, 3000 series). A person skilled in the art will understand that other suitable metals could be utilized to form the divider sheets 40, 44 so long as the divider sheets 40, 44 prevent permeation of the coolant 90 past the divider sheets 40, 44 and through the sheet assemblies 30.
As shown in
As can be seen in
The first cathode sheet 21 further includes a first cathode sheet inner surface 21I located opposite the first cathode sheet outer surface 21O, as shown in
The first divider sheet outer surface 40O is also substantially planar and flat such that the first divider sheet 40 lies flat against the first cathode sheet 21. In some embodiments, the first divider sheet 40 and the first cathode sheet 21 are parallel with each other when the divider sheet 40 is arranged on the cathode sheet 21. The first divider sheet outer surface 40O may be adhered to a majority of the first cathode sheet outer surface 21O. As will be described in greater detail below, the first divider sheet outer surface 40O may be sanded or treated with other processes to improve adhesion between the divider sheet 40 and the cathode sheet 21.
As shown in
The passages 23 may be formed as elongated grooves 23 in the second cathode sheet 22 that open outwardly away from the second cathode sheet outer surface 22O. A coolant fluid 90 may be circulated through the plurality of passages 23 in order to cool the bipolar plate assembly 10. The coolant fluid 90 may include, but is not limited to, water (e.g., deionized water) or ethylene glycol. A person skilled in the art will understand that other coolants may be utilized based on the design requirements and operating conditions of the bipolar plate assembly 10.
The second cathode sheet 22 further includes a second cathode sheet inner surface 22I located opposite the second cathode sheet outer surface 22O, as shown in
The first divider sheet inner surface 40I is also substantially planar and flat such that the first divider sheet 40 lies flat against the second cathode sheet 22. In some embodiments, the first divider sheet 40 and the second cathode sheet 22 are parallel with each other when the divider sheet 40 is arranged on the cathode sheet 22. The first divider sheet inner surface 40I may be adhered to a majority of the second cathode sheet inner surface 22I. As will be described in greater detail below, the first divider sheet inner surface 40I may be sanded or treated with other processes to improve adhesion between the divider sheet 40 and the cathode sheet 22.
As shown in
The anode sheet outer surface 32O forms an outer side of the bipolar plate assembly 10 and is configured to interact with the anode gas diffusion layer 126 of the fuel cell 120. In some embodiments, the anode sheet 32 may further include a plurality of passages 34 formed on the anode sheet outer surface 32O. The passages 34 may be formed as elongated grooves 34 in the anode sheet 32 that open outwardly away from the anode sheet outer surface 32O. The passages 34 may form one of the active areas 19 of the bipolar plate assembly 10 described above. In this active area 19, fuel (e.g., hydrogen) is configured to flow through the passages 34 and thus interacts with the anode gas diffusion layer 126.
The anode sheet 32 further includes an anode sheet inner surface 32I located opposite the anode sheet outer surface 32O, as shown in
The second divider sheet outer surface 44O is also substantially planar and flat such that the second divider sheet 44 lies flat against the anode sheet 32. In some embodiments, the second divider sheet 44 and the anode sheet 32 are parallel with each other when the divider sheet 44 is arranged on the anode sheet 32. The second divider sheet outer surface 44O may be adhered to a majority of the anode sheet outer surface 32O. As will be described in greater detail below, the second divider sheet outer surface 44O may be sanded or treated with other processes to improve adhesion between the divider sheet 44 and the anode sheet 32.
The assembled bipolar plate 10 includes the cathode sheet assembly 20 and the anode sheet assembly 30 coupled to each other so as to form the bipolar plate assembly 10, as shown in
As can be seen in
Illustratively, each of the first divider sheet 40 and the second divider sheet 44 has a length that is longer than a length of each of the first cathode sheet 21, the second cathode sheet 22, and the anode sheet 32, as shown in
The portions of the divider sheets 40, 44 that extend beyond the cathode and anode sheets 21, 22, 32 may be welded to each other at welding joints 48, 50 to strengthen the coupling of the cathode and anode assemblies 20, 30 to each other, thus forming a more robust bipolar plate assembly 10. Utilizing welding for coupling the anode and cathode together rather than typical adhesion methods, such as adhesive glues, provides increased structural strength while not affecting the full bipolar plate assembly 10 electrical conductivity. In one embodiment, the cathode and anode 124, 126 of the fuel cell 120 are coupled together without the use of glues, adhesives (e.g., heat-resistant adhesive), and/or fasteners (e.g., bolts, screws, etc.).
In operation, the bipolar plate assembly 10 includes coolant fluid 90 flowing through the passages 23 to cool the bipolar plate 10. Because the cathode sheets 21, 22 and the anode sheet 32 are formed of polymer composite materials, the coolant fluid 90 may permeate from the passages 23 and into the cathode sheets 21, 22 and the anode sheet 32. As can be seen in
Although some of the coolant fluid 90 may reach the first divider sheet 40, the metallic material of the first divider sheet 40 is configured to prevent the coolant fluid 90 from continuing to permeate past the divider sheet 40. As such, the first divider sheet 40 prevents the coolant fluid 90 from permeating through the first cathode sheet 21 and reaching the first cathode sheet outer surface 21O, such that the coolant fluid 90 cannot interact with the cathode gas diffusion layer 124. Similarly, the second divider sheet 44 is configured to prevent the fluid from permeating through the anode sheet 32 and reaching the anode sheet outer surface 32O, such that the coolant fluid 90 cannot interact with the anode gas diffusion layer 126.
As described above, in some embodiments, the coolant fluid 90 may be water such as filtered water, sterilized water, and in particular deionized water. Deionized water may be utilized in fuel cell operating conditions of approximately 70° C. to 90° C., including any specific or range of temperatures comprised therein. However, in some embodiments, in particular in operating conditions of less than 0° C., it may be desirable to utilize ethylene glycol as the coolant fluid 90.
In typical bipolar plates, using ethylene glycol may be too precarious due to the risk of permeation of the ethylene glycol through the cathode and anode assemblies 20, 30 and into the gas diffusion layers 124, 126. The ability of the divider sheets 40, 44 to entirely prevent any permeation of the coolant fluid 90 through the cathode and anode sheet assemblies 20, 30 allows for the use of ethylene glycol as the coolant fluid 90 of the bipolar plate assembly 10. The metallic divider sheets 40, 44 also increase full bipolar plate electrical conductivity, while maintaining high thermal conductivity and high flexural strength, which are advantageous for fuel cell health and extension of fuel cell life.
As shown in
As such, in the illustrated embodiment, the second divider sheet 44 is sanded to create an appropriate level of surface roughness on the divider sheet 44 prior to compression molding. The sanding creates a surface energy value of the metal that is closer to that of the polymer composite material of the anode sheet 32. As such, the second divider sheet 44 and the anode sheet 32 will sufficiently adhere to each other during the compression molding process, such that there is no need for additional glues, adhesives, and/or fasteners.
After the second divider sheet 44 is prepared, the divider sheet 44 is placed on a bottom press plate 72 of the anode compression mold 70, as shown in
The compression mold 70 is then opened and the anode sheet assembly 30 (metallic divider sheet 44 coupled to the polymer composite anode sheet 32) is removed from the mold 70. A polymer coating 35 may be created by this process between the anode sheet inner surface 32I and the second divider sheet outer surface 44O. This polymer coating 35 does not extend beyond the terminal ends of the anode sheet 32, as can be seen in
Thus, the exposed end portions 45, 46 of the divider sheet 44 may be welded to the exposed end portions 41, 42 of the first divider sheet 40 without damaging the materials, in particular the polymer composite materials and the polymer coating. Specifically, the welding process would burn the polymer coating if it were present on the exposed end portions 41, 42, 45, 46. The structure and formation of the anode sheet assembly 30, in particular the polymer composite material and the polymer coating 35 not extending into the exposed end portions 45, 46, enables the utility of welding to couple the anode sheet assembly 30 to the cathode sheet assembly 20 without the use of additional glues, adhesives, and/or fasteners.
As shown in
After the first divider sheet 40 is prepared, the divider sheet 40 is placed between two pucks 21P, 22P made from polymer composite material, as shown in
Next, the top press plate 84 is lowered with a first force 86, and pressure is applied on the pucks 21P, 22P and the divider sheet 40. As can be seen in
The compression mold 80 is then opened and the cathode sheet assembly 20 (e.g., metallic divider sheet 40 coupled to the polymer composite cathode sheets 21, 22 on opposing sides of the divider sheet 40) is removed from the mold 80. A polymer coating 51, 52 may be created by this process between the cathode sheet inner surfaces 21I, 22I and the first divider sheet outer and inner surfaces 40O, 40I, respectively. This polymer coating 51, 52 does not extend beyond the terminal ends of the cathode sheets 21, 22, as can be seen in
Thus, the exposed end portions 41, 42 of the divider sheet 40 may be welded to the exposed end portions 45, 46 of the second divider sheet 44 without damaging the materials, in particular the polymer composite materials and the polymer coating. The structure and formation of the cathode sheet assembly 20, in particular the polymer composite material and the polymer coating 51, 52 not extending into the exposed end portions 41, 42, enables the utility of welding to couple the cathode sheet assembly 20 to the anode sheet assembly 30 without the use of additional glues, adhesives, and/or fasteners.
In some embodiments, the initial step of preparing the first and second divider sheets 44 by sanding may be eliminated. In such embodiments, the compression of the metallic divider sheets 40, 44 and the respective sheets 21, 22, 32 may provide sufficient adhesion strength. In other embodiments, instead of sanding the divider sheets 40, 44, the initial step of preparing the divider sheets 40, 44 may include treating the metallic divider sheets 40, 44 with a plasma process, corona treatment, or by applying a chemical functionalizing agent to the divider sheet 40, 44 surface.
A method of forming a bipolar plate assembly of a fuel cell is disclosed herein. The method includes a first operation of providing a first cathode sheet, a second cathode sheet, and a first divider sheet. The first cathode sheet includes a first cathode sheet outer surface opposite the first divider sheet and is configured to interact with a cathode gas diffusion layer of the fuel cell. The second cathode sheet includes a second cathode sheet outer surface that is opposite the first divider sheet. The method further includes a second operation of arranging the first divider sheet between the first cathode sheet and the second cathode sheet.
The method further includes a third operation of providing an anode sheet and a second divider sheet. The anode sheet includes an anode sheet outer surface and an anode sheet inner surface opposite the anode sheet outer surface. The anode sheet outer surface is configured to interact with an anode gas diffusion layer of the fuel cell. The method further includes a fourth operation of arranging the second divider sheet on the anode sheet inner surface.
In some embodiments, the second cathode sheet outer surface is arranged on the second divider sheet such that the anode sheet assembly and the cathode sheet assembly form the bipolar plate. The second cathode sheet includes at least one passage formed therein. The at least one passage includes a fluid flowing therein.
The first divider sheet is configured to prevent the fluid from permeating through the first cathode sheet and reaching the first cathode sheet outer surface, such that the fluid cannot interact with the cathode gas diffusion layer. The second divider sheet is configured to prevent the fluid from permeating through the anode sheet and reaching the anode sheet outer surface such that the fluid cannot interact with the anode gas diffusion layer.
In some embodiments of the method, the arranging of the second divider sheet on the anode sheet inner surface includes adhering the second divider sheet on the anode sheet inner surface. Prior to adhering the second divider sheet on the anode sheet inner surface, the method further includes a fifth operation of sanding or treating a side of the second divider sheet to be arranged on the anode sheet inner surface. The sanding or treatment is to create surface roughness and increase adhesion between the second divider sheet on the anode sheet inner surface.
While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
There is a plurality of advantages of the present disclosure arising from the various features of the method, apparatus, and system described herein. It will be noted that alternative embodiments of the method, apparatus, and system of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the method, apparatus, and system that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present disclosure as defined by the appended claims.
The features illustrated or described in connection with one 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 the present disclosure. Further, a person skilled in the art will recognize that terms commonly known to those skilled in the art may be used interchangeably herein.
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the presently described subject matter are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Specified numerical ranges of units, measurements, and/or values comprise, consist essentially or, or consist of all the numerical values, units, measurements, and/or ranges including or within those ranges and/or endpoints, whether those numerical values, units, measurements, and/or ranges are explicitly specified in the present disclosure or not.
Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms “first,” “second,” “third” and the like, as used herein do not denote any order or importance, but rather are used to distinguish one element from another. The term “or” is meant to be inclusive and mean either or all of the listed items. In addition, the terms “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect.
Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. The term “comprising” or “comprises” refers to a composition, compound, formulation, or method that is inclusive and does not exclude additional elements, components, and/or method steps. The term “comprising” also refers to a composition, compound, formulation, or method embodiment of the present disclosure that is inclusive and does not exclude additional elements, components, or method steps.
The phrase “consisting of” or “consists of” refers to a compound, composition, formulation, or method that excludes the presence of any additional elements, components, or method steps. The term “consisting of” also refers to a compound, composition, formulation, or method of the present disclosure that excludes the presence of any additional elements, components, or method steps.
The phrase “consisting essentially of” or “consists essentially of” refers to a composition, compound, formulation, or method that is inclusive of additional elements, components, or method steps that do not materially affect the characteristic(s) of the composition, compound, formulation, or method. The phrase “consisting essentially of” also refers to a composition, compound, formulation, or method of the present disclosure that is inclusive of additional elements, components, or method steps that do not materially affect the characteristic(s) of the composition, compound, formulation, or method steps.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” and “substantially” is not to be limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
As used herein, the terms “may” and “may be” indicate a possibility of an occurrence within a set of circumstances; a possession of a specified property, characteristic or function; and/or qualify another verb by expressing one or more of an ability, capability, or possibility associated with the qualified verb. Accordingly, usage of “may” and “may be” indicates that a modified term is apparently appropriate, capable, or suitable for an indicated capacity, function, or usage, while taking into account that in some circumstances, the modified term may sometimes not be appropriate, capable, or suitable.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used individually, together, or in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the subject matter set forth herein without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the disclosed subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the subject matter described herein should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
This written description uses examples to disclose several embodiments of the subject matter set forth herein, including the best mode, and also to enable a person of ordinary skill in the art to practice the embodiments of disclosed subject matter, including making and using the devices or systems and performing the methods. The patentable scope of the subject matter described herein is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
This nonprovisional application claims the benefit and priority, under 35 U.S.C. § 119(e) and any other applicable laws or statutes, to U.S. Provisional Application No. 63/350,670 filed on Jun. 9, 2022, the entire disclosure of which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63350670 | Jun 2022 | US |
