Resin impregnation of bipolar plates

Abstract

The present disclosure relates generally to systems and methods for impregnating a resin in one or more coolant channels in a bipolar plate before or after assembling the bipolar plate into a fuel cell stack.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Pursuant to 35 U.S.C. §119(e) and any other applicable law or regulation, this nonprovisional application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 300,503, filed on January 18, 2022, the entire disclosure of which is hereby expressly incorporated herein by reference. Technical Field

[0002] The present disclosure generally relates to methods of reducing leakage in graphite bipolar plates by resin impregnation. Background Art

[0003] Several fuel cell stacks are assembled into a fuel cell stack and operated to provide power or energy for industrial use. In many mobility applications, it is highly advantageous to assemble one or more fuel cells or fuel cell stacks to achieve volumetric power density, which better allows for improved vehicle integration.

[0004] A fuel cell is a multi-component system including a membrane electrode assembly (MEA) at the center, gas diffusion layers (GDL) on both sides of the membrane electrode assembly (MEA), and bipolar plates (BPP) on the other side of the gas diffusion layer (GDL). The membrane electrode assembly (MEA) is a component that enables electrochemical reactions in a fuel cell.

[0005] Reactants supplied to the fuel cell include a fuel (e.g., hydrogen, such as pure hydrogen) supplied at the anode and an oxidant (e.g., oxygen) supplied at the cathode. The anode is typically supplied with hydrogen from highly compressed gaseous or liquefied hydrogen stored in a built-in tank. A cooling system including a coolant fluid is typically configured to be connected to the fuel cell stack to provide a controllable heat sink for excess heat generation during the electrochemical reaction occurring in the fuel cell stack.

[0006] Bipolar plates (BPP) in fuel cells may develop leaks due to the porosity or brittleness of the materials. For example, bipolar plates (BPP) made of graphite or graphite composites are brittle and may develop cracks during production, transportation and handling. Bipolar plates (BPP) may also develop cracks during the joining or assembly of sub-plates (e.g., plates that have not yet been joined to form a bipolar plate (BPP)). This is typical if the joining of the plates or sub-plates is done by adhesive bonding and if the bonding material is not leakproof. Leakage can lead to undesirable penetration of reactants or coolants. Therefore, it is desirable to reduce penetration as much as possible.

[0007] Resin impregnation is a suitable method for rendering porous materials impermeable. The conventional resin impregnation method has several limitations as it requires large equipment and involves large volumes of chemicals. The vacuum vessel used for resin impregnation is typically cylindrical and must be larger in volume than the sub-panel being impregnated. The use of such a large volume of vacuum vessels increases the footprint of the facility, the amount of chemicals consumed, and the waste generated by such a process.

[0008] Because conventional resin impregnation is used prior to bipolar plate formation, this treatment can only address pores and micropores in the sub-plate material, but not any defects introduced by downstream processes such as bipolar plate (BPP) manufacturing or transportation and handling. In addition, any subsequent processes used for bipolar plate manufacturing must be performed at temperatures that avoid compromising the effects of the resin impregnation. Because the resin is applied to all surfaces of the sub-plate, i.e., anode, cathode, and coolant channels, the resin may increase surface resistance or affect chemical interactions within the MEA or GDL, all of which can affect fuel cell performance.

[0009] Therefore, a method for resin impregnation of fuel cell bipolar plates (BPP) specifically through coolant channels is described herein. Summary of the invention

[0010] Embodiments of the present disclosure are included to satisfy these and other needs.

[0011] In one aspect, a method of impregnating a bipolar plate with a resin is described herein, comprising creating a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate by opening a first valve and closing a second valve, flowing a resin stored in a reservoir through the one or more coolant channels in the bipolar plate by closing the first valve and opening the second valve, exhausting the resin from the one or more coolant channels by opening the first valve and opening the second valve, flowing air into the one or more coolant channels to further exhaust the resin, washing the one or more coolant channels by flowing a non-ionic surfactant into the one or more coolant channels, and impregnating the one or more coolant channels in the bipolar plate with the resin stored in the resin reservoir. One or more holes in the one or more coolant channels in the bipolar plate are filled with the resin.

[0012] In some embodiments, the method may include generating a vacuum in one or more anode channels, one or more cathode channels, or one or more coolant channels in the bipolar plate by a vacuum pump. In some embodiments, the method may include maintaining a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate for about 1 hour. In some embodiments, the method may include introducing pneumatic pressure into one or more coolant channels to force the resin to penetrate into the bipolar plate. In some embodiments, cleaning one or more coolant channels by flowing a non-ionic surfactant into one or more coolant channels may include using a pump to flow a non-ionic surfactant stored in a solution reservoir.

[0013] In some embodiments, the method may include cleaning one or more coolant channels with deionized water. In some embodiments, the method may include curing a resin for filling one or more holes of a coolant channel in a bipolar plate. In some embodiments, the method may include curing a resin for filling one or more holes of a coolant channel in a bipolar plate. In some embodiments, curing the resin may include heating the bipolar plate using temperature control when the bipolar plate is not assembled into a fuel cell stack. In some embodiments, curing the resin may include flowing water at a temperature of about 90°C to about 100°C through one or more coolant channels when the bipolar plate is assembled into a fuel cell stack. In some embodiments, the water may be maintained at a temperature of about 90°C to about 100°C by a heater coil, a water bath, or a heat exchanger.

[0014] In some embodiments, the resin used to fill the one or more holes of the coolant channel can be cured without disassembling the bipolar plate that has been assembled into the fuel cell stack. In some embodiments, impregnating the one or more coolant channels in the bipolar plate with the resin can be performed without causing any chemical interaction with any other layer of the fuel cell. In some embodiments, the method can be applied after manufacturing the bipolar plate from two sub-plates.

[0015] In some embodiments, the diameter of one or more holes may be greater than about 100 nm, and the holes may be sealed with a resin to prevent any leakage of the coolant. In some embodiments, the resin may have a viscosity of less than about 100 cPs. In some embodiments, the resin may be cured at a temperature below about 100° C. In some embodiments, the resin may withstand a temperature of about 90° C.

[0016] In some embodiments, the method may further include preventing the resin from contaminating a membrane in a fuel cell stack including a bipolar plate. In some embodiments, a fuel cell stack may include a membrane isolated from a manifold region including a coolant port.

[0017] According to a second aspect described herein, a system for impregnating a resin into one or more coolant channels in a bipolar plate includes a resin reservoir, a first valve, and a second valve. The resin reservoir includes a heat-curable and low-viscosity resin. The first valve is connected to a vacuum pump, wherein the opening of the first valve creates a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate. The second valve is connected to the resin reservoir, wherein the opening of the second valve fills the one or more coolant channels in the bipolar plate with resin.

[0018] According to a third aspect described herein, a system for cleaning resin from one or more coolant channels in a bipolar plate includes a solution reservoir, a first valve, a second valve, and a pump. The solution reservoir contains a non-ionic surfactant solution. The first valve is connected to a vacuum pump, wherein the opening of the first valve creates a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate. The second valve is connected to the solution reservoir, wherein the opening of the second valve fills the one or more coolant channels in the bipolar plate with the non-ionic surfactant solution. The pump is connected between the solution reservoir and the second valve, wherein the pump drives the non-ionic surfactant solution into the one or more coolant channels in the bipolar plate.

[0019] In some embodiments, the solution reservoir may include deionized water. In some embodiments, a pump may drive the deionized water into one or more coolant channels in the bipolar plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A is a schematic diagram of an exemplary fuel cell system including an air delivery system, a hydrogen delivery system, and a fuel cell module including a plurality of fuel cell stacks;

[0021] Figure 1B is a cross-sectional view of an exemplary fuel cell system including an air delivery system, a hydrogen delivery system, and a plurality of fuel cell modules, each including a plurality of fuel cell stacks;

[0022] Figure 1C yes Figure 1A A perspective view of an exemplary repeating unit of a fuel cell stack of a fuel cell system of FIG.

[0023] Figure 1D yes Figure 1C A cross-sectional view of an exemplary repeating unit of a fuel cell stack;

[0024] Figure 2 shows a cross section of a fuel cell stack including a sub-plate in a bipolar plate;

[0025] Figure 3 An impregnation system including a vacuum pump, a resin reservoir and two valves is shown;

[0026] Figure 4 A rinse system including a solution reservoir and a pump is shown;

[0027] Figure 5A shows the layout of the membrane electrode assembly and subgasket in a fuel cell;

[0028] Figure 5B shows the layout of a membrane electrode assembly (MEA) and subgaskets extending to both ends of the MEA;

[0029] Figure 5C shows a layout of a membrane electrode assembly (MEA) and subgaskets that do not extend to both ends of the MEA; and

[0030] Figure 6 A fuel cell is shown where the coolant port is isolated from the membrane electrode assembly.

[0031] When reading the following detailed description with reference to the drawings described herein, these and other features, aspects and advantages of the present invention will become better understood. Reference is also made to the drawings forming a part of this article, and specific embodiments in which the present invention can be practiced are shown therein by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the claimed content, and it should be understood that other embodiments may be utilized and logical, mechanical and electrical changes may be made without departing from the spirit and scope of the claims. Therefore, the following detailed description is not intended to be limiting. DETAILED DESCRIPTION

[0032] like Figure 1A As shown in FIG. 1 , a fuel cell system 10 generally includes one or more fuel cell stacks 12 or fuel cell modules 14 connected to a balance of plant (BOP) 16 including various components to support electrochemical conversion, generation and / or distribution of electrical power to help meet modern industrial and commercial needs in an environmentally friendly manner. Figure 1B and 1C As shown in FIG. 1 , the fuel cell system 10 may include a fuel cell stack 12 including a plurality of individual fuel cells 20. Each fuel cell stack 12 may accommodate a plurality of fuel cells 20 assembled together in series and / or in parallel. The fuel cell system 10 may include one or more fuel cell modules 14, such as Figure 1A and 1B as shown in .

[0033] Each fuel cell module 14 may include a plurality of fuel cell stacks 12 and / or a plurality of fuel cells 20. The fuel cell module 14 may also include a suitable combination of associated structural elements, mechanical systems, hardware, firmware, and / or software that are used to support the function and operation of the fuel cell module 14. These items include, but are not limited to, piping, sensors, regulators, current collectors, seals, and insulators.

[0034] The fuel cells 20 in the fuel cell stacks 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 requirements of any loads. The number of fuel cells 20 in the fuel cell stacks 12 can vary depending on the amount of power required to operate the fuel cell system 10 including the fuel cell stacks 12.

[0035] The number of fuel cells 20 in each fuel cell stack 12 or fuel cell system 10 can be any number. For example, the number of fuel cells 20 in each fuel cell stack 12 can range from about 100 fuel cells to about 1000 fuel cells, including any specific number or range of fuel cells 20 contained therein (e.g., about 200 to about 800). In one embodiment, the fuel cell system 10 may include about 20 to about 1000 fuel cell stacks 12, including any specific number or range of fuel cell stacks 12 contained therein (e.g., about 200 to about 800). The fuel cells 20 in the fuel cell stacks 12 within the fuel cell module 14 can be oriented in any direction to optimize the operating efficiency and functionality of the fuel cell system 10.

[0036] The fuel cell 20 in the fuel cell stack 12 may be any type of fuel cell 20. The fuel cell 20 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 cell 20 may be a polymer electrolyte membrane or proton exchange membrane (PEM) fuel cell or a solid oxide fuel cell (SOFC).

[0037] exist Figure 1C In the embodiment shown in FIG. 1 , 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 gas diffusion layers (GDL) 24, 26 on either or both sides of the membrane electrode assembly (MEA) 22 (see FIG. 1 ). Figure 1CThe fuel cell 20 also includes bipolar plates (BPP) 28, 30 on the outside of each gas diffusion layer (GDL) 24, 26, such as Figure 1C 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 comprise a single repeating unit 50 .

[0038] The bipolar plates (BPP) 28, 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) in the fuel cell 20. The bipolar plates (BPP) 28, 30 can evenly distribute the reactants 32, 34 to the active area 40 of each fuel cell 20 through oxidant flow fields 42 and / or fuel flow fields 44 formed on the outer surfaces of the bipolar plates (BPP) 28, 30. When viewing the stack 12 from a top-down perspective, the active area 40 where electrochemical reactions occur to produce the electrical power generated by the fuel cell 20 is centered within the membrane electrode assembly (MEA) 22, the gas diffusion layers (GDL) 24, 26, and the bipolar plates (BPP) 28, 30.

[0039] Each of the bipolar plates (BPP) 28, 30 may be formed to have reactant flow fields 42, 44 formed on opposing outer surfaces of the bipolar plates (BPP) 28, 30, and to have a coolant flow field 52 located within the bipolar plates (BPP) 28, 30, as shown in FIG. Figure 1D For example, the bipolar plates (BPP) 28, 30 may include a fuel flow field 44 for transporting the fuel 32 on one side of the plates 28, 30 for interaction with the gas diffusion layer (GDL) 26, and an oxidant flow field 42 for transporting the oxidant 34 on an opposing second side of the plates 28, 30 for interaction with the gas diffusion layer (GDL) 24. Figure 1D As shown in , the bipolar plates (BPP) 28, 30 may also include a coolant flow field 52 formed within the plates (BPP) 28, 30, generally centered between the opposing outer surfaces of the plates (BPP) 28, 30. The coolant flow field 52 facilitates the flow of a cooling fluid 36 through the bipolar plates (BPP) 28, 30 to regulate the temperature of the plate (BPP) 28, 30 materials and reactants. The bipolar plates (BPP) 28, 30 are pressed against the adjacent gas diffusion layers (GDL) 24, 26 to isolate and / or seal one or more reactants 32, 34 within their respective channels 44, 42 to maintain electrical conductivity, which is required for robust operation of the fuel cell 20 (see Figure 1C and 1D ).

[0040] The fuel cell system 10 described herein may be used in stationary and / or non-stationary power systems, such as industrial applications and power plants. The fuel cell system 10 may also be implemented in conjunction with an air delivery system 18. Additionally, the fuel cell system 10 may also be implemented in conjunction with a hydrogen delivery system and / or a hydrogen source 19, such as a pressurized tank, including a gas pressurized tank, a cryogenic liquid storage tank, a chemical storage, a physical storage, a stationary storage, an electrolysis system, or an electrolyzer. In one embodiment, the fuel cell system 10 is connected and / or attached in series or in parallel to a hydrogen delivery system and / or a hydrogen source 19, such as one or more hydrogen delivery systems and / or hydrogen sources 19 in a BOP 16 (see Figure 1A In another embodiment, the fuel cell system 10 is not connected and / or attached to the hydrogen delivery system and / or hydrogen source 19 in series or parallel.

[0041] The present fuel cell system 10 may also be included in mobile applications. In an exemplary embodiment, the fuel cell system 10 is in a vehicle and / or powertrain 100. The vehicle 100 including the present fuel cell system 10 may be an automobile, a passenger car, a bus, a truck, a train, a locomotive, an aircraft, a light vehicle, a medium vehicle, or a heavy vehicle. The types of vehicles 100 may also include, but are not limited to, commercial vehicles and engines, trains, carts, trams, airplanes, buses, ships, boats, and other known vehicles, as well as other machinery and / or manufacturing devices, equipment, installations, and the like.

[0042] The vehicle and / or powertrain 100 may be used on roads, highways, railroads, airways, and / or waterways. The vehicle 100 may be used in applications including, but not limited to, off-road transportation, bobtails, and / or mining equipment. For example, an exemplary embodiment of the mining equipment vehicle 100 is a mining truck or a mine haul truck.

[0043] In addition, it will be appreciated by those of ordinary skill in the art that the fuel cell system 10, fuel cell stack 12, and / or fuel cell 20 described in the present disclosure may replace any electrochemical system, such as an electrolysis system (e.g., an electrolyzer), an electrolyzer stack, and / or an electrolyzer cell (EC). Therefore, in some embodiments, the features and aspects of the fuel cell system 10, stack 12, or battery 20 described and taught in the present disclosure also relate to an electrolyzer, an electrolyzer stack, and / or an electrolyzer cell (EC). In other embodiments, the features and aspects described or taught in the present disclosure do not relate to and are therefore distinguishable from the features and aspects of an electrolyzer, an electrolyzer stack, and / or an electrolyzer cell (EC).

[0044] The present disclosure relates to systems and methods for resin 202 impregnation of a fuel cell bipolar plate (BPP) through coolant channels only, such as Figure 3-5. The methods and systems described herein can be used after assembling a bipolar plate (BPP) from sub-plates or even after a fuel cell stack is fully assembled. Systems and methods are described herein for handling leaks and / or defects caused during assembly of a bipolar plate (BPP) and / or during assembly of a fuel cell or fuel cell stack.

[0045] A cross-section of a typical repeating unit 50 of a fuel cell stack 12 is shown in Figure 2 The fuel cell stack 12 generally includes a membrane electrode assembly (MEA) 22, a gas diffusion layer (GDL) 24, and a bipolar plate (BPP) 28. The bipolar plates (BPP) 28, 30 provide channels or flow fields 42, 52, 44 for transporting an oxidant 34, a coolant 36, and a fuel 32, while providing mechanical support and electrical contact in the fuel cell stack 12.

[0046] Each bipolar plate (BPP) 28 is made by joining two sub-plates 122 to form the three isolated fluid channels or flow fields 42, 52, 44 described above. The fuel 32 (e.g., hydrogen) flows on one side of the anode or fuel channel or flow field 44, the oxidant 34 (e.g., air) flows on the second side of the cathode or air channel or flow field 42, and the coolant 36 flows in the coolant channel or flow field 52 in the volume enclosed by the two sub-plates 122.

[0047] The bipolar plates (BPP) 28, 30 or sub-plates 122 may be metal substrates or carbon substrates. Carbon-based bipolar plates (BPP) 28, 30 or sub-plates 122, including those made of graphite, graphite composites, or flexible graphite, provide lower costs and longer durability than bipolar plates (BPP) 28, 30 or sub-plates 122 made of metal. Resin 202 impregnation may be used to treat the sub-plates 122 to fill any pores, micropores, holes, defects, or cracks therein.

[0048] Resin 202 impregnation includes using a low viscosity, heat curable resin 202 to infiltrate voids and cracks in the bipolar plates (BPP) 28, 30. However, resin 202 impregnation is primarily applied to individual sub-plates 122. In addition, conventional resin 202 impregnation is typically performed on flexible graphite plates, rather than on bipolar plates (BPP) 28, 30 comprising other materials.

[0049] Conventional resin 202 impregnation includes completely immersing the sub-plate 122 in the resin 202 under vacuum to allow the resin 202 to penetrate the pores, micropores, holes, defects and / or cracks in the material. Once the impregnation is complete, the sub-plate 122 is rinsed to remove any residual surface resin 202 and heated to allow the resin 202 within the pores, micropores, holes, defects or cracks to cure. The resin-impregnated sub-plates 122 are then bonded to produce the bipolar plates (BPP) 28, 30. However, as previously described, this conventional method has substantial problems, including not correcting leaks or defects formed during the bonding of the sub-plates 122.

[0050] The present disclosure describes a method of resin 202 impregnation that may be used before the bipolar plates (BPP) 28, 30 are assembled from the sub-plates 122, after the bipolar plates (BPP) 28, 30 are assembled from the sub-plates 122, before the fuel cell stack 12 is fully assembled, and / or after the fuel cell stack 12 is fully assembled. Because the resin 202 is in contact only with the coolant channels 52 of the bipolar plates (BPP) 28, 30, there is no expected increase in surface resistance or interference of the resin 202 with the core operation of the fuel cell 20 or the fuel cell stack 12.

[0051] When the method described herein is applied at the end of the manufacture of the bipolar plates (BPP) 28, 30, the method allows for the treatment of leaks or defects caused during the assembly of the bipolar plates (BPP) 28, 30 in the preparation of the fuel cell stack 12 assembly or during the assembly of the fuel cell stack 12. The daughter plates 122 may be bonded to the bipolar plates (BPP) 28, 30 by any method, including bonding or welding.

[0052] The bipolar plates (BPP) 28, 30 may be assembled into the fuel cell stack 12 by press clamping or by using fasteners such as bolts, screws, hinges, etc. The resin 202 impregnation after the sub-plates 122 are bonded to form the bipolar plates (BPP) 28, 30 may correct any bonding leaks or defects formed during the bonding process, including but not limited to the methods listed above. The sub-plates 122 that are subjected to the resin 202 impregnation after the bipolar plates (BPP) 28, 30 are assembled into the fuel cell stack 12 may or may not have been impregnated with the resin 202 before being bonded to form the bipolar plates (BPP) 28, 30.

[0053] The resin 202 impregnation method can be used to treat pores, micropores, holes, defects and / or cracks ranging in size from about 100 nm to about 500 nm, including any specific or range of sizes contained therein. For example, these pores, micropores, holes, defects and / or cracks can have sizes ranging from about 200 nm to about 300 nm, from about 300 nm to about 500 nm, including any sizes contained therein. In some embodiments, the resin 202 impregnation can be used to treat pores, micropores, holes, defects or cracks greater than about 500 nm or less than about 100 nm.

[0054] like Figure 3-4 As shown in , the disclosed method of resin 202 impregnation includes passing the resin 202 through the coolant passages 52, which does not affect the performance of the fuel cell stack 12 including the treated sub-plates 122 or bipolar plates (BPP) 28, 30. This method seals defects in the coolant passages 52 and thus prevents the coolant 36 from leaking into the fuel passages 44 and / or the oxidant passages 42.

[0055] The method of impregnating the bipolar plates (BPP) 28, 30 with a resin 202 prior to assembling the bipolar plates (BPP) 28, 30 into the fuel cell stack 12 includes using an impregnation system 200. An embodiment of the impregnation system 200 is shown in Figure 3 The impregnation system 200 includes a vacuum pump 222 , a resin reservoir 226 , and valves 224 , 220 .

[0056] One or more bipolar plates (BPP) 28, 30 are sandwiched between two rigid clamps 212. The clamps 212 consist of port connections 218, 216, and 214. The anode port 217 and cathode port 219 are connected to a vacuum pump 222 at port connection 218. The coolant port 215 is connected to the vacuum pump 222 at port connection 214 and to a resin reservoir 226 at port connection 216.

[0057] The resin 202 stored in the resin reservoir 226 is a low viscosity, heat-curable resin 202. In one embodiment, the low viscosity of the resin 202 can be about 3 centipoise (cPs). In other embodiments, the low viscosity of the resin 202 can range from about 1 cPs to about 100 cPs, including any specific or range of viscosities contained therein. For example, the low viscosity can range from about 1 cPs to about 20 cPs, about 20 cPs to about 50 cPs, about 50 cPs to about 80 cPs, about 80 cPs to about 100 cPs, or any viscosity or viscosity range contained therein.

[0058] The resin 202 generally includes a curing temperature depending on its composition. The curing temperature of the resin 202 may be in the range of about 80°C to about 120°C, including any specific or range of temperatures contained therein. Specifically, the curing temperature of the resin 202 may be in the range of about 80°C to about 90°C, about 90°C to about 100°C, about 100°C to about 110°C, about 110°C to about 120°C, including any specific or range of temperatures contained therein. For example, the range of the curing temperature may be about 100°C to about 120°C, including any temperature or temperature range contained therein. Typically, the curing temperature is about 120°C or lower. Alternatively, the curing temperature may be about 100°C or lower. The performance of the fuel cell stack 12 impregnated with the resin 202 at higher temperatures is negatively affected.

[0059] In addition, the resin 202 in the resin reservoir 226 should be able to withstand the operating temperature of the fuel cell stack 12 after curing. The operating temperature of the fuel cell stack 12 can range from about 85° C. to about 95° C., including any temperature or temperature range subsumed therein. For example, the resin 202 does not decompose, crack, or malfunction at the operating temperature of the fuel cell stack 12.

[0060] like Figure 3 , the method of resin 202 impregnation includes opening valve 220 and using vacuum pump 222 to generate vacuum in anode and / or fuel channel 44 and in air and / or cathode channel 42. Impregnation system 200 can be configured to maintain vacuum time for extended periods under vacuum to completely evacuate the air in pores, micropores, holes, defects and / or cracks. The range of vacuum time for extended periods can be about 1 hour to about 3 hours, including any specific or range of time contained therein. For example, the range of vacuum time for extended periods can be about 2 hours to about 3 hours, including any time or time range contained therein.

[0061] The method of resin impregnation includes closing valve 220 and opening valve 224 to allow resin 202 from resin reservoir 226 to fill the entire coolant channel 52 in all bipolar plates (BPP) 28, 30 in the fuel cell 20 or fuel cell stack 12. In some embodiments, pneumatic pressure may be introduced into the coolant channel 52 to force the resin 202 from the resin reservoir 226 to penetrate into the bipolar plates (BPP) 28, 30. The pneumatic pressure may be supplied by an air compressor 230 and / or from a compressed gas container 232. The pneumatic pressure may depend on the size and configuration of the resin reservoir 226 and / or the size of the bipolar plates (BPP) 28, 30, and may be any specific or range of pressures sufficient to provide force to the resin to implement the present method.

[0062] The method of resin 202 impregnation includes draining the coolant passage 52 by opening valves 220 and 224 and introducing a gas flow 234 through the coolant passage 52. The gas flow 234 will help drain excess resin 202 from the bipolar plates (BPP) 28, 30. The gas flow 234 may be supplied by an air compressor 230 or from a compressed gas container 232.

[0063] The method of resin 202 impregnation prior to assembling the bipolar plates (BPP) 28, 30 into the fuel cell stack 12 includes washing, cleaning and / or rinsing the interior of the coolant channels 52 of the bipolar plates (BPP) 28, 30. The rinsing system 300 is shown in FIG. Figure 4 In the rinse system 300, the resin reservoir 226 is replaced with a solution reservoir 310 containing a cleaning solution 308. Alternatively, the resin 202 can be replaced with the cleaning solution 308 in the resin reservoir 226. In some embodiments, the resin reservoir 226 can be the same as the solution reservoir 310. In other embodiments, the resin reservoir 226 can be different from the solution reservoir 310.

[0064] The cleaning solution 308 may include, but is not limited to, a surfactant, a nonionic solution, and a solution of a nonionic surfactant. Preferably, the cleaning solution 308 for cleaning the resin 302 may be a nonionic surfactant. An exemplary nonionic surfactant cleaning solution 308 for cleaning the resin 302 is Triton X-100.

[0065] The rinse system 300 may also include a pump 312. The method of cleaning, cleaning and / or rinsing the interior of the coolant passages 52 includes opening the valves 220 and 224 and recirculating the cleaning solution 308 through the coolant passages 52 of the bipolar plates (BPP) 28, 30 using the pump 312. Since both valves 220 and 224 are open and a vacuum is no longer maintained within the rinse system 300, the pump 312 helps circulate the cleaning solution 308 through the coolant passages 52 of the bipolar plates (BPP) 28, 30.

[0066] The cleaning solution 308 in the solution reservoir 310 may be replaced one or more times until the resin 202 is completely washed out of the interior of the coolant channel 52. The cleaning solution 308 may be replaced from about 2 to about 5 times, including any number of times subsumed therein. In some embodiments, if all the resin is not washed out of the interior of the coolant channel 52, the cleaning solution 308 may be replaced more than 5 times.

[0067] The method of cleaning, cleaning and / or rinsing the interior of the coolant channel 52 includes replacing the cleaning solution 308 in the solution reservoir 310 with water (e.g., deionized water) 306 to rinse the cleaning solution 308 out of the coolant channel 52. Therefore, the method of cleaning, cleaning and / or rinsing the interior of the coolant channel 52 also includes rinsing the cleaning solution 308 out of the coolant channel 52 with water (e.g., deionized water) 306. The method of cleaning, cleaning and / or rinsing the interior of the coolant channel 52 includes opening valves 220 and 224 and recirculating the deionized water 306 through the coolant channel 52 of the bipolar plate (BPP) 28, 30 using a pump 312. The deionized water 306 can be replaced multiple times during the recirculation. The deionized water 306 can be replaced from about 2 times to about 5 times, including any number contained therein. In some embodiments, the deionized water 306 can be replaced more than 5 times.

[0068] The method of resin 202 impregnation before assembling the bipolar plates (BPP) 28, 30 into the fuel cell stack 12 includes curing the resin in the interior of the coolant channels 52 of the bipolar plates (BPP) 28, 30 by applying temperature-controlled heat. The method of curing the resin 202 includes removing the bipolar plates (BPP) 28, 30 from the system 200, 300 and heating them at the aforementioned curing temperature. The method includes heating the bipolar plates (BPP) 28, 30 at the curing temperature in a controlled manner. For example, the resin 202 can be cured in a temperature-controlled oven. The temperature and time to fully cure the resin 202 depends on the chemical properties of the resin 202 used for impregnation.

[0069] In addition, the time to cure the resin 202 depends on the curing temperature. However, in general, the resin can be cured using a temperature-controlled heat or a temperature-controlled oven ranging from about 80° C. to about 120° C., including any specific or range of temperatures subsumed therein. In a preferred embodiment, the temperature-controlled heat or oven does not exceed a maximum temperature of 120° C.

[0070] In such a temperature controlled environment, the time for curing the resin is typically in the range of about 0.5 hours to about 3 hours, including any specific or range of times contained therein. For example, at a curing temperature of about 100° C., the curing time for resin 202 is about 1 hour. If the temperature is reduced, the curing time may need to be extended. Alternatively, the temperature and time for fully curing resin 202 can be based on recommendations from a resin 202 supplier, based on a differential scan of resin 202 to determine the curing temperature range for resin 202, and / or based on a curing experiment performed (e.g., in real time) to determine the optimal temperature and time for curing resin 202.

[0071] The method of resin 202 impregnation after assembling the bipolar plates (BPP) 28, 30 into the fuel cell stack 12 includes using an impregnation system 200 including a vacuum pump 222, a resin reservoir 226, and valves 224, 220, such as Figure 3 The method of resin impregnation after assembling the bipolar plates (BPP) 28, 30 into the fuel cell stack 12 includes cleaning the interior of the coolant channels 52 of the bipolar plates (BPP) 28, 30 using a rinse system 300, such as Figure 4 As shown in and discussed above.

[0072] This method of curing the resin 202 after impregnation of the resin 202 and assembly of the bipolar plates (BPP) 28, 30 to the fuel cell stack 12 includes curing the resin 202 in the interior of the coolant channels 52 of the bipolar plates (BPP) 28, 30 by applying heat without disassembling the fuel cell stack 12. The method of curing the resin 202 includes causing heat transfer through the fuel cell stack 12 and protecting the membrane electrode assembly (MEA) 22 of the fuel cell stack 12 from heat damage.

[0073] The fuel cell stack 12 including the bipolar plates (BPP) 28, 30 is heated by circulating hot water 304 after being impregnated with the resin 202. The method of curing the bipolar plates (BPP) 28, 30 using the hot water 304 circulation includes using Figure 4 The method includes recirculating the hot water 304 through the coolant channels 52 of the bipolar plates (BPP) 28 , 30 in the fuel cell stack 12 .

[0074] The hot water 304 in the solution reservoir 310 is maintained between about 80°C and about 120°C, including any temperature or range contained therein. The temperature is maintained by a heater coil 340, a water bath 342, a heat exchanger 344, and / or a different heating mechanism. The hot water 304 is continuously recirculated until the entire fuel cell stack 12 reaches a temperature for the time required to cure the resin 202. The hot water 304 can be recirculated at a flow rate of about 0.5L / min per plate to about 1L / min per plate, including any flow rate or range contained therein. The flow rate at which the hot water 304 circulates depends on, including but not limited to, the length of the coolant channel 52, the number of bipolar plates (BPP) 28, 30 in the fuel cell stack 12, the design of the fuel cell stack 12, and the viscosity of the resin 202 used.

[0075] The above-described method of impregnating the resin 202 through the coolant passage 52 includes preventing the resin 202 from penetrating the MEA 22 of the fuel cell stack 12. Figures 5A-5CAs shown in FIG. 4 , the MEA 22 in the fuel cell stack 400, 420, 440 includes a membrane 410, an anode catalyst 412, and a cathode catalyst 414. The MEA 22 is surrounded by a subgasket 416 on both sides.

[0076] Subgasket 416 may be made of plastic. Exemplary plastics for subgasket 416 include polyethylene naphthalate (PEN) or polyethylene terephthalate (PET). The layout of subgasket 416, anode catalyst 410, cathode catalyst 414, and membrane 410 is parallel and extends to Figure 5B-5C The end 444 of the fuel cell stack 420 , 440 is shown in FIG.

[0077] like Figure 5C As shown in FIG, the MEA 22 including the anode catalyst 410, the cathode catalyst 414, and the membrane 410 does not extend to the end 442 in the fuel cell stack 440. When the membrane 410 including the anode catalyst 410, the cathode catalyst 414 does not extend to the end 442 and the coolant port is located at the end 442, the resin 202 does not penetrate into the MEA 22 during the impregnation process.

[0078] Or, if Figure 5B As shown in , the MEA 22 including the anode catalyst 410, the cathode catalyst 414 and the membrane 410 extends to the end 444 in the fuel cell stack 420. In such a configuration, the resin 202 may not penetrate into the MEA 22 during the above-mentioned impregnation process because the coolant port 215 in the fuel cell stack 444 is isolated from the MEA 22. The coolant port 215 can be isolated from the MEA 22 by a sealant 520 (as shown in FIG. 6) or by design. If the anode catalyst 410, the cathode catalyst 414 and the membrane 410 extend to the end 444 in the fuel cell stack 420, the coolant port 215 can be isolated from the MEA 22 by design so that the MEA 22 does not contact the subgasket 416 at the location of the coolant port 215.

[0079] like Figure 6 As shown in FIG. 5 , the MEA 22 and the subgasket 416 in the fuel cell stack 500 are stacked in an “H” shape so that the area of ​​the coolant port 215 does not contact the MEA 22. In addition, the coolant port 215 has a double sealant design 510 for isolation. The coolant port 215 is separated by a first sealant 520 and a second sealant 530 that isolate the MEA 22 from the manifold area 512.

[0080] Due to this double sealant design, when there is a fault in the structure of the coolant port 215, leakage of the coolant or any resin 202 flowing through the coolant port 215 will cause external leakage, but will still not affect the performance of the MEA 22. In other embodiments, the MEA 22 and the subgasket 416 may not be stacked in an "H" shape, but the MEA 22 may be isolated from the manifold area 512 and the coolant port 215 by a different design.

[0081] The above-described method of resin 202 impregnation through coolant passages 52 may include preventing contamination of the MEA 22 by the resin 202. Preventing contamination of the MEA 22 may include using a fuel cell stack 500 that isolates the MEA 22 from the manifold region 512. Notably, preventing MEA contamination through the presently described resin impregnation method advantageously extends the life, durability, and overall performance of the fuel cell stack, which ultimately benefits power generation suppliers, consumers, and / or users of power and electricity generated by the fuel cells.

[0082] The following described aspects of the invention are intended to be non-limiting:

[0083] A first aspect of the present invention relates to a method for impregnating a bipolar plate with a resin. The method includes creating a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate by opening a first valve and closing a second valve, allowing the resin stored in the reservoir to flow through the one or more coolant channels in the bipolar plate by closing the first valve and opening the second valve, allowing the resin to be discharged from the one or more coolant channels by opening the first valve and opening the second valve, allowing air to flow into the one or more coolant channels to further discharge the resin, washing them by flowing a non-ionic surfactant into the one or more coolant channels, and impregnating the one or more coolant channels in the bipolar plate with the resin stored in the resin reservoir. One or more holes in the one or more coolant channels in the bipolar plate are filled with resin.

[0084] A second aspect of the present invention relates to a system for impregnating a resin into one or more coolant channels in a bipolar plate. The system includes a resin reservoir, a first valve, and a second valve. The resin reservoir includes a heat-curable and low-viscosity resin. The first valve is connected to a vacuum pump, wherein the opening of the first valve creates a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate. The second valve is connected to the resin reservoir, wherein the opening of the second valve fills the one or more coolant channels in the bipolar plate with resin.

[0085] A third aspect of the present invention relates to a system for cleaning resin from one or more coolant channels in a bipolar plate. The system includes a solution reservoir, a first valve, a second valve, and a pump. The solution reservoir contains a non-ionic surfactant solution. The first valve is connected to a vacuum pump, wherein the opening of the first valve creates a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate. The second valve is connected to the solution reservoir, wherein the opening of the second valve fills the one or more coolant channels in the bipolar plate with a non-ionic surfactant solution. The pump is connected between the solution reservoir and the second valve, wherein the pump drives the non-ionic surfactant solution into one or more coolant channels in the bipolar plate. The solution reservoir may contain deionized water. The pump may drive deionized water into one or more coolant channels in the bipolar plate.

[0086] In a first aspect of the invention, the method may include generating a vacuum in one or more anode channels, one or more cathode channels, or one or more coolant channels in a bipolar plate by a vacuum pump. In a first aspect of the invention, the method may include maintaining a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in a bipolar plate for about 1 hour. In a first aspect of the invention, the method may include introducing pneumatic pressure into one or more coolant channels to force the resin to penetrate into the bipolar plate. In a first aspect of the invention, cleaning one or more coolant channels by flowing a non-ionic surfactant into one or more coolant channels may include using a pump to flow a non-ionic surfactant stored in a solution reservoir.

[0087] In a first aspect of the invention, the method may include rinsing one or more coolant channels with deionized water. In a first aspect of the invention, the method may include curing a resin for filling one or more holes of a coolant channel in a bipolar plate. In a first aspect of the invention, the method may include curing a resin for filling one or more holes of a coolant channel in a bipolar plate. In a first aspect of the invention, curing the resin may include heating the bipolar plate using temperature control when the bipolar plate is not assembled into a fuel cell stack. In a first aspect of the invention, curing the resin may include flowing water at a temperature of about 90°C to about 100°C through one or more coolant channels when the bipolar plate is assembled into a fuel cell stack. In a first aspect of the invention, the water may be maintained at a temperature of about 90°C to about 100°C by a heater coil, a water bath, or a heat exchanger.

[0088] In a first aspect of the invention, the resin used to fill the one or more holes of the coolant channel can be cured without disassembling the bipolar plate that has been assembled into the fuel cell stack. In a first aspect of the invention, the impregnation of the one or more coolant channels in the bipolar plate with the resin can be performed without causing any chemical interaction with any other layer of the fuel cell. In a first aspect of the invention, the method can be applied after the bipolar plate is manufactured from two sub-plates.

[0089] In the first aspect of the invention, the diameter of one or more holes can be greater than about 100nm, and the holes can be sealed with a resin to prevent any leakage of the coolant. In the first aspect of the invention, the resin can have a viscosity of less than about 100cPs. In the first aspect of the invention, the resin can be cured at a temperature below about 100°C. In the first aspect of the invention, the resin can withstand a temperature of about 90°C.

[0090] In the first aspect of the invention, the method may further include preventing resin from contaminating a membrane in a fuel cell stack including a bipolar plate. In the first aspect of the invention, the fuel cell stack may include a membrane isolated from a manifold region including a coolant port.

[0091] As used herein, an element or step described in singular form and beginning with the word "one" or "an" should be understood to not exclude the plural number of the element or step, unless such exclusion is explicitly stated. In addition, the reference to "one embodiment" of the subject matter currently described is not intended to be interpreted as excluding the existence of additional embodiments that also include the features. The numerical range of the specified unit, measurement result and / or value includes, is substantially composed of or is composed of all numerical values, units, measurement results and / or ranges including or within those ranges and / or endpoints, regardless of whether these numerical values, units, measurement results and / or ranges are clearly specified in the present disclosure.

[0092] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present disclosure belongs. As used herein, the terms "first", "second", "third", etc. do not indicate any order or importance, but are used to distinguish one element from another. The term "or" is inclusive and represents any one or all of the listed items. In addition, the terms "connect" and "couple" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings, whether direct or indirect.

[0093] In addition, unless explicitly stated to the contrary, embodiments that "comprise," "include," or "have" an element or elements having a particular property may include additional such elements that do not have that property. The terms "comprising" or "including" refer to compositions, compounds, formulations, or methods that include, but do not exclude, additional elements, components, and / or method steps. The term "comprising" also refers to compositions, compounds, formulations, or method embodiments of the present disclosure that include, but do not exclude, additional elements, components, or method steps.

[0094] The phrase "consisting of" or "consisting of" refers to compounds, compositions, formulations, or methods that do not include any additional elements, components, or method steps. The term "consisting of" also refers to compounds, compositions, formulations, or methods of the disclosure that do not include the presence of any additional elements, components, or method steps.

[0095] The phrase "consisting essentially of" or "consisting essentially of" refers to compositions, compounds, formulations, or methods that include additional elements, components, or method steps that do not materially affect one or more characteristics of the composition, compound, formulation, or method. The phrase "consisting essentially of" also refers to compositions, compounds, formulations, or methods of the disclosure that include additional elements, components, or method steps that do not materially affect one or more characteristics of the composition, compound, formulation, or method step.

[0096] Approximate language as used throughout the specification and claims herein can be used to modify any quantitative representation that may allow variation without causing a change in the basic function associated therewith. Therefore, values ​​modified by one or more terms such as "about" and "substantially" are not limited to the precise values ​​specified. In some cases, approximate language may correspond to the precision of the instrument used to measure the value. Here and throughout the specification and claims, range limitations can be combined and / or interchanged. Unless the context or language indicates otherwise, such ranges are determined and include all subranges contained therein.

[0097] As used herein, the terms "may" and "might be" indicate the possibility of occurring under a set of circumstances; possessing a particular characteristic, feature, or function; and / or qualifying another verb by expressing one or more of the ability, capacity, or possibility associated with the qualifying verb. Thus, the use of "may" and "might be" indicates that the modified term is clearly suitable, capable, or applicable to the specified capacity, function, or use, while taking into account that in some cases, the modified term may sometimes not be appropriate, capable, or suitable.

[0098] It should be understood that the above description is intended to be illustrative, not restrictive. For example, the above embodiments (and / or aspects thereof) may be used alone, together, or in combination with each other. In addition, without departing from its scope, many modifications may be made to adapt specific situations or materials to the teachings of the subject matter set forth herein. Although the size and type of materials described herein are intended to define the parameters of the disclosed subject matter, they are by no means restrictive and are exemplary embodiments. After reviewing the above description, many other embodiments will be apparent to those skilled in the art. Therefore, the scope of the subject matter described herein should be determined with reference to the appended claims together with the full scope of equivalents enjoyed by such claims.

[0099] This written description uses examples to disclose several embodiments of the subject matter described herein, including the best mode, and also to enable one of ordinary skill in the art to practice the embodiments of the disclosed subject matter, including making and using devices or systems and performing methods. The patentable scope of the subject matter described herein is defined by the claims, and may include other examples that occur to one 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 language of the claims.

[0100] Although only certain features of the present invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the invention.

Claims

1. A method for impregnating a resin in a bipolar plate, comprising: creating a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate by opening a first valve and closing a second valve, by closing the first valve and opening the second valve, allowing the resin stored in the reservoir to flow through one or more coolant channels in the bipolar plate, draining the resin from the one or more coolant channels by opening the first valve and opening the second valve, allowing air to flow into the one or more coolant channels to further evacuate the resin, cleaning the one or more coolant channels by flowing a non-ionic surfactant into the one or more coolant channels, impregnating one or more coolant channels in the bipolar plate with resin stored in the resin reservoir, Wherein one or more holes in one or more coolant channels in the bipolar plate are filled with resin.

2. The method according to claim 1, wherein: The vacuum in one or more anode channels, one or more cathode channels, or one or more coolant channels in the bipolar plate is generated by a vacuum pump.

3. The method according to claim 1, wherein: The method also includes cleaning the one or more coolant channels with deionized water.

4. The method according to claim 3, wherein: The method also includes curing the resin used to fill the one or more holes of the coolant channels in the bipolar plate.

5. The method according to claim 4, wherein: Curing the resin includes temperature-controlled heating of the bipolar plate when the bipolar plate is not assembled into a fuel cell stack.

6. The method according to claim 4, wherein: Curing the resin includes flowing water at a temperature of about 90° C. to about 100° C. through the one or more coolant channels when the bipolar plate is assembled into a fuel cell stack.

7. The method according to claim 1, wherein: The resin used to fill the one or more holes of the coolant channel is cured without disassembling the bipolar plate that has been assembled into the fuel cell stack.

8. The method according to claim 1, wherein: Impregnation of the one or more coolant channels in the bipolar plate with the resin is accomplished without causing any chemical interaction with any other layer of the fuel cell.

9. The method according to claim 1, wherein: The method is applied after the bipolar plate has been produced from two partial plates.

10. The method according to claim 1, wherein: The resin may be cured at temperatures below about 100°C.

11. The method according to claim 1, wherein: The resin can withstand temperatures of about 90°C.

12. The method according to claim 1, wherein: The method includes preventing the resin from contaminating a membrane in a fuel cell stack including the bipolar plate.

13. The method according to claim 12, wherein: The fuel cell stack includes a membrane isolated from a manifold region including a coolant port.

14. A system for impregnating a resin into one or more coolant channels in a bipolar plate, comprising: a resin reservoir containing a heat-curable and low-viscosity resin, a first valve connected to a vacuum pump, wherein opening of the first valve creates a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate, and A second valve is connected to the resin reservoir, wherein opening of the second valve fills one or more coolant channels in the bipolar plate with the resin.

15. A system for cleaning resin from one or more coolant channels in a bipolar plate, comprising: a solution reservoir containing a non-ionic surfactant solution, a first valve connected to a vacuum pump, wherein opening of the first valve creates a vacuum in one or more anode channels, one or more cathode channels, and one or more coolant channels in the bipolar plate, a second valve connected to the solution reservoir, wherein opening of the second valve fills one or more coolant channels in the bipolar plate with the non-ionic surfactant solution, and A pump is connected between the solution reservoir and the second valve, wherein the pump drives the non-ionic surfactant solution into one or more coolant channels in the bipolar plate.

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