Air shaping means for even fluid distribution to fuel cell stack

Abstract

An air-shaping insert 700 is configured to mate with a duct 601 in a fuel cell stack 600, and comprises a multi-vane airflow assembly. The assembly comprises a front face acting as an inlet for the ai

Description

[0001] The present disclosure relates to fuel cell assemblies, and in particular to membranetype fuel cells, as well as methods of evaporative cooling during operation. BACKGROUND

[0002] A typical fuel cell system includes a fuel cell stack for generating electricity, a hydrogen supply as a fuel to the fuel cell stack, an oxygen (air) supply system for supplying oxygen containing air as an oxidant for the electrochemical reaction and thermal management for removing reaction heat from the fuel cell stack and managing humidity in the stack and water removal. The fuel cell system generates heat and water as well as electricity.

[0003] A typical fuel cell stack 1 known in the art (Figure 1) includes fuel cell assemblies, each unit, has an anode, a cathode, and an electrolyte (electrolyte membrane). Hydrogen is supplied to the anode and oxygen containing air is supplied to the cathode. By way of a membrane electrode assembly (MEA) 3 the hydrogen and oxygen and water for hydration are fed into the fuel cell stack by way of inlet and outlet ports or manifolds 4 &6 and the fuel cell stack produces electricity, heat, and water.

[0004] A stack is typically in the form of a block comprising numerous individual fuel cells or fuel cell assemblies 10A through 10N plates held together by end plates at either end of the stack. The fuel cells, prior to final assembly and compression, are often formed in groupings or modules 12A-12N. It is also important that the temperature of the stack is controlled. Thus, coolant may be supplied to the stack for cooling and / or hydration.

[0005] An important consideration in the operation of such fuel cells is the management of water within the MEA. During operation of a PEM fuel cell, product water from the reaction between hydrogen and oxygen is formed at catalytic sites of the MEA. This water is in one or more phases of liquid, vapor and transitional depending on temperature and pressure when produced and it must be exhausted from the MEA via the cathode diffusion structure at the same time that oxygen is transported to the cathode face of the MEA. However, it is also important that the MEA remains suitably hydrated to ensure that the internal electrical resistance of the cell remains within tolerable limits. Failure to control the MEA humidification leads to hot spots and potential cell failure and / or poor electrical cell performance. The anode and cathode fluid flow field plates may each include a rigid, electrically conductive, material having fluid flow channels in the surface adjacent the respective diffusion structure for delivery of the reactant gases (for example, hydrogen and oxygen) and removal of the exhaust gases (for example, unused oxygen and water vapor).

[0006] Fuel cell stacks comprise a series of individual fuel cells built up layer by layer into a stack arrangement. Each fuel cell itself may include various layered components, such as a polymer electrolyte membrane, gas diffusion layers, fluid flow plates, and various sealing gaskets for maintaining fluid tightness and providing fluid fuel and oxidant distribution to the active surfaces of the membrane. The fluid inputs and fluid outputs are direct through flow fields and plates at the fuel cell level and through connected manifolds at the stack level. Inherent in fuel cell stacks having common ducts or manifolds aligned between fuel cells in a stack to distribute fluids such as air is that air flow is unevenly distributed down the length of the duct or manifold resulting in a non-homogeneous distribution of air. The nonhomogeneity of air distribution results in uneven voltage between fuel cells within the stack. It is therefore a desideratum to overcome such traditional challenges. DISCLOSURE

[0007] The following description of examples of implementations, reference is made to the accompanying drawings that form a part hereof, and which show, by way of illustration, specific implementations of the present disclosure that may be utilized. Other implementations may be utilized, and structural changes may be made without departing from the scope of the present disclosure.

[0008] The disclosure addresses fluid flow limitations in fuel cell stacks. Specifically, a system, method, and device to shape air within a common manifold or duct wherein a more even distribution of air between the fuel cells forming a stack from the first fuel cell to the last fuel cell in the stack is achieved. The improved homogeneity of air distribution results in more even cooling and heating up of the fuel cells forming the stack and more even voltage between fuel cells within the stack. The instant disclosure teaches shaping bodies such as vanes or deflectors positioned to shape the airflow within a duct or manifold inlet for air of the fuel cell stack.

[0009] The disclosure addresses fluid flow limitations in fuel cell stacks. Specifically, a system, method, and device to shape air within a common manifold or duct wherein a more even distribution of air occurs the system and device includes the multi-vane airflow assembly forming an air shaping insert (ASI) is configured to fit into one or more air inlet / intake ducts formed in a fuel cell stack. The multi-vane airflow assembly has a front face (7configured to receive airflow, a back wall of the front face configured to support a plurality of vanes. Each of the plurality of vanes affixed at one end to said back wall and each having a free end. The plurality of vanes of the ASI have differing lengths measured from said backside. One or more of the plurality of vanes have a curvature of their body configured to direct airflow in the duct. Each ASI evens out the mass airflow in the duct between fuel cells forming the stack.

[0010] In some instances at least one of the plurality of vanes is split having at least two extended arms and a connector region therebetween configured to form an open region between said extended arms and each arm is attached the back side of the front face and each has a free end. In some instances the distance between the two arms at the connector region is less than the distance between the free ends. In some instances each arm has a curved top inside edge between the connector region and the free end in some instances at least one of the open region and curved top edge directs and / or shapes airflow.

[0011] The disclosure addresses fluid flow limitations in fuel cell stacks. Specifically, a system, method, and device to shape air within a common manifold or duct wherein a more even distribution of air occurs the system and device includes the multi-vane airflow assembly forming an air shaping insert (ASI) is configured to fit into one or more air inlet / intake ducts formed in a fuel cell stack. The multi-vane airflow assembly has a front face configured to receive airflow, a back wall of the front face configured to support a plurality of vanes. Each of the plurality of vanes affixed at one end to said back wall and each having a free end. The plurality of vanes of the ASI have differing lengths measured from said backside. One or more of the plurality of vanes have a curvature of their body configured to direct airflow in the duct and at least one outside wall formed extended from at least one side edges of the front face to at least one of direct airflow and anchor said plurality of vanes. In some instances at least one second side wall formed extended from the backside to at least one of direct airflow and anchor said plurality of vanes. In some instances at least one third side wall formed extended from the backside to at least one of direct airflow and anchor said plurality of vanes.

[0012] The disclosure addresses fluid flow limitations in fuel cell stacks. Specifically, a system, method, and device to shape air within a common manifold or duct wherein a more even distribution of air of inserting a multi-vane airflow assembly configured with a plurality of vanes forming an air shaping insert (ASI) and each having a free end into a duct formed in a fuel cell stack. Each of said plurality of vanes have differing lengths and one or more of the plurality of vanes have a curvature of their body configured to direct airflow in the duct. The ASI evens out the mass airflow in the duct between fuel cells forming the stack. In some instances the fuel cell stack has a plurality of ducts and there is one multi-vane airflow assembly inserted in each duct. Each duct has a front end and a remote end and said ASI vanes extend between 8% and 30% into the duct from the first end. In some instances the imbalance of mass airflow between the front end of a duct and the remote end is one of less than 9% and 10%.

[0013] The disclosure addresses fluid flow limitations in fuel cell stacks. Specifically, a system, method, and device to shape air within a common manifold or duct wherein a more even distribution of air of inserting a multi-vane airflow assembly configured with a plurality of vanes forming an air shaping insert (ASI) and each having a free end into a duct formed in a fuel cell stack. Each of said plurality of vanes have differing lengths and one or more of the plurality of vanes have a curvature of their body configured to direct airflow in the duct. The ASI evens out the mass airflow in the duct between 432 fuel cells forming the stack. In some instances the fuel cell stack has a plurality of ducts and there is one multi-vane airflow assembly inserted in each duct. Each duct has a front end and a remote end and said ASI vanes extend between 8% and 30% into the duct from the first end. In some instances the output of said fuel cells stack is between about 3.4 and about 6.8 times greater than the fuel cell stack without the ASI. In some instances the fuel cell stack configured with an ASI produces at least one of 120kW, 125kW, 130kW, 140kW, 145kW, 150kW, 155kW, 160kw, 165kW, and !70kw a; and. the same fuel cell stack without an ASI produces and output of compared to an output of between 25kWs and 35kWs. FIGURES

[0014] The present application is further understood when read in conjunction with the appended drawings. For the purpose of illustrating the subject matter, there are shown in the drawings exemplary aspects of the subject matter; however, the presently disclosed subject matter is not limited to the specific methods, devices, and systems disclosed.

[0015] The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.

[0016] Fig. 1 depicts a traditional fuel cell stack prior art.

[0017] Fig. 2 depicts a side exploded assembly view of a high efficiency fuel cell assembly.

[0018] Fig. 3illustrates an exploded view of aspects and some components of a fuel cell assembly.

[0019] Fig. 4 illustrates a perspective view of an end of a fuel cell stack showing air inlets.

[0020] Fig. 5 illustrates a component view of a fuel cell stack and multiple air inlets.

[0021] Fig. 6 shows a cutaway view of the fuel cell stack of Fig. 5 with the air inlet manifold attached.

[0022] Fig. 7 A shows a front top perspective view of air shaping insert (ASI).

[0023] Fig. 7B shows a front view of the ASI of Figure 7A.

[0024] Figs. 7C and 7D show aspects of variations of the ASI of figure 7A.

[0025] Fig. 8. shows a side view of Fig. 7A.

[0026] Fig. 9 shows a cutaway side view of a fuel cell stack with an extended vane or fins formed in the ASI.

[0027] Fig. 10 shows a cutaway side view of a fuel cell stack having multiple ASI inserted into via multiple modules.

[0028] Fig. 11 is a bar graph showing performance and impact on airflow volume distribution in a configuration without air shaping of the airflow in the duct.

[0029] Fig. 12 is a bar graph showing performance and impact on airflow volume distribution in a configuration with various air shaping of the airflow in the duct.

[0030] All descriptions and callouts in the Figures and all content therein are hereby incorporated by this reference as if fully set forth herein. All citations are hereby incorporated by this reference as if fully set forth herein. Aspects of the disclosure will now be described in detail with reference to the drawings, wherein like reference numbers refer to like elements throughout, unless specified otherwise. FURTHER DISCLOSURE

[0031] The present disclosure may be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this disclosure is not limited to the specific devices, methods, applications, conditions, or parameters described and / or shown herein, and that the terminology used herein is for the purpose of describing particular exemplars by way of example only and is not intended to be limiting of the claimed disclosure.

[0032] Disclosed herein is a method and system to increase output of a fuel cell stack from producing 25 or even 35kWs to the same fuel cell stack producing between 120 kWs to 170 kWs. This can be accomplished within the same footprint fuel cell stack by leveraging the existing air inlet ducting.

[0033] Figure 2 illustrates components of a fuel cell assembly. A membrane electrode assembly (MEA) containing a proton exchange membrane (also known as a polymer electrolyte membrane) is normally a multi-layer interface whereby protons from the anode side of a fuel cell cross the MEA and the stripped off electron travels around the MEA to generate electricity. On the cathode side oxygen is provided and the hydrogen protons eventually form water with some of the oxygen provided.

[0034] The MEA 12 in a fuel cell assembly (or a fuel cell) traditionally will have some gas diffusion layer or layers between the MEA and bipolar frame 13. Ona first side of the MEA 12A which will be closest to the cathode face 14 of a bipolar frame 13 is a cathode gas diffusion layer (or layers) 15. On the opposite second side of the MEA 12B which will be closest to the anode face 16 of a bipolar frame 13 is an anode gas diffusion layer 17. The bipolar frame 13 has a first end 18 opposite a second end 19. On one side of the MEA oxidant and water for hydration are fed through one end and removed at the other end. On the other side of the bipolar plate fuel is fed through one end and removed at the other end. One or more gaskets are added to seal the fuel cell assembly when forming fuel cells within a fuel cell stack. At least a cathode gasket 40 and an anode gasket 42. Air and water are supplied to the cathode side of the fuel cell assembly by way of inlets in the fuel cell assembly. Hydrogen is supplied to the anode side of the fuel cell assembly by way of inlets on the anode side of the fuel cell assembly.

[0035] Figure 4 illustrates an exploded view of a fuel cell assembly 100. A first frame 200A and a second frame 200B enclose the MEA 12. A water distribution guide or plate 300 distributes water to the MEA. Oxidant is provided to the fuel cell cathode air inlets 402 and exits the fuel cell via cathode outlet manifolds 403. Fuel enters the fuel cell via fuel inlets 404 and exits the fuel cell via fuel outlet manifolds 405. Water enters the fuel cell via water inlets 406 and exits the fuel cell via water outlet manifolds 407. Figure 5 illustrates fuel cell assemblies 100A-N stacked together in a module 500. The air inlets are aligned in a stack and form a duct down the length of the stack.

[0036] Figure 5 illustrates a fuel cell stack 600 with an air distribution conduit 650 formed of modules 500A-500F each module contains a plurality of fuel cell assemblies with ducts 601 formed by the aligned air inlet manifolds.

[0037] The skilled artisan and those of ordinary skill in the art will recognize that the design choice of grouping pluralities of fuel cells into modules and then stacking the modules to form the fuel cell stack is not a limitation of the invention and it is an equivalent for purposes of the airflow disclosed herein to a fuel cell stack of hundreds of separate fuel cells which are not modularized.

[0038] At a first end of the fuel cell stack is the first fuel cell assembly 100A of the first module, at the first end a cover 610 is attached. Adjacent to the second end of the fuel cell stack at the last fuel cell assembly 100N of the last module forming the fuel cell stack is a second end cover 612. The open front of the duct 614 is where air enters the stack. When operational airflow is directed into said duct and then distributed into fuel cells forming the stack. If the mass air flow distribution is uneven the fuel cells forming the stack will also have uneven output and thus reduce efficiency of the fuel cells stack. Said second end cover acts as a duct end 615 which is remote from the front at the portion of the duct most remote from the front of the duct for the duct formed by the air inlet manifolds. Said end covers may be multipart. Said end covers can be compressed with the fuel cell assemblies and modules during the build of the fuel cell stack. The first end cover 610 is configured with a series of air inlet interfaces 605 which align with the air inlets 402 of the fuel cell assemblies and the ducts 601 formed thereby. A series of air distribution connections 655 align with and each one is fluidly connected to an air inlet and are configured to distribute air supplied to the distribution conduit via the air supply 660 to the series of distribution connections 655 and into the fuel cell stack. The electrical output of such a fuel cell stack is limited by the mass flow of air into the fuel cell stack. We have observed that a traditional fuel cells stack, even with modules 500A-500F is limited to about 30kW of output due to the variation in mass air flow volume between each fuel cell’s air inlet.

[0039] In traditional fuel cell stacks although the same volume of air is supplied to each of the distribution connections 655 the fluid dynamics and physics of moving the air through the stack is suboptimal for even volume air distribution to all fuel cells in the stack.

[0040] Figure 6 shows a cut away view of a four hundred and thirty-two fuel cells stack illustrating the placement of aspects of an air shaping insert (ASI) 700 extending from one of the first fuel cell 100A and the first end cover 610, distributing air into the duct 601. A front portion of the fuel cell stack of fuel cells 602 is shown.

[0041] Figure 6 also shows a four hundred and thirty-two fuel cells stack and the ASI 700. Our tests showed that an ASI near the top of the fuel cell stack (closest to the first fuel cell) reduces the imbalance between the first fuel cell in the stack 100A and the last fuel cell in the stack 100N from about 240% with no ASI to approximately 9% with an ASI.

[0042] Figures 7A to 9 shows aspects of an exemplary ASI configured to shape or redirect air entering a duct 601 by way of a first fin or vane703, a second fin or vane 705 and a third fin or vane 707. Optionally, additional fins or vanes 750 may be added. In some instances an ASI is split. In some instances, a fin or vane is configured with one or more side walls 704. Figure 7A illustrates a multi-vane assembly 700. The entry region for airflow is via the face 701 of the multi-vane assembly forming the air shaping insert (ASI). The face has a top surface 701’. The first vane 703 is illustrated with several air directing features. Aspects include a plurality of extended arms forming the first vane (also referred to as “fin”). Shown in Figures 7A-7D are two such arms, which are not a limitation. The left arm 703A and the right arm 703B forming a first vane or fin whereby a portion of air to be shaped is direct through a connector 703C into an open region 710 with a width “dl” at the base and a second width “d2” at the free end 703 A’ and 703B’ of each right and left leg. Optionally, each arm 703 has a curved top inside edge 703D between the connector region and the free end. The shape of the curved top inside edge is also configured to shape and direct airflow. Between the right and left arm. inside guides walls 704 may be added, optionally, to assist with the distribution of air into the duct. Figure 7B illustrates a front face 701’ of the ASI and a plurality of quadrants A1-C3 which correspond to regions of airflow into each fin or vane. The size and shape of the quadrants are defined by the side walls and the vanes. The openings that are the area of each quadrant are configured to provide air distribution within the duct of a predefined shape and volume throughout the duct. Said area of the opening and the shape of the inside guides and sidewalls, if added, as well as the material forming the ASI are factors that will affect the airflow and fluid dynamics of the air distribution and air volumetries within the duct. The second fin 705 is longer than the first fin and has a second length “d4”, the third fin 707 is further from the front face and has a length of “d5”. The optional extra vane 750 has the greatest length “d6” from the front face 701. Figures 7C and 7D illustrate aspects and variations of the ASI shown in Figure 7A. The front face 701’ may have curved portions 701” resulting in a face with different width regions. Along the sides edges 712 of the face, outside walls 702 direct airflow and, are shown as anchors for at least a portion of each vane. Side walls 704 also shape air flow and can form anchors for vanes. Second side walls 706 and third side walls 708 also shape air flow and can form anchors for one or more vanes.

[0043] The skilled artisan and those of ordinary skill in the art will recognize that the configuration of quadrants is not limited to the nine quadrants shown and a greater or lesser number of quadrants are within the scope of the disclosure. Further, the skilled artisan and those of ordinary skill in the art will recognize that the length or curvature of vanes or fins adjacent to quadrants described or shown in figures is not intended to be a limitation.

[0044] The ASI is preferably not electrically conductive. Further the ASI can be smooth or rough to direct the airflow. There may be areas on fins or vanes which are more or less lubricous or have varying Reynolds numbers compared to other areas. Additional dimples, divots, bumps, and the like may be added to the fins or vane surface to impart swirl, disrupt airflow or add chaotic motion to the airflow passing over said fin or vane.

[0045] The vanes are non-homogeneous in at least one of length and curvature. The length and curvature correspond in part to the length of the duct 601. Generally, the ASI extends 8% to 30%the length of the duct. In some instances the longest vane extends down starting at the front of the duct 614 from 8 % to 12% of the duct length, in some instances the longest vane extends from 10% to 15% the length of the duct In some instances, depending on mass airflow the longest vane extends from the front of the duct 15% to 20% into the duct. In some instances, the longest vanes extend from the front of the duct at least one of 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% and 30%.

[0046] Figure 8 and Figure 9 illustrate cut away side views of the ASIs including in one instances with an optional extra vane 750. The third fin 707 is the shortest shown at a first length “d3” from the front face 701, the second fin 705 is longer than the third fin and has a second length “d4”, the first fin 703 is further from the front face and has a length of “d5”. The optional extra vane 750 has the greatest length “d6” from the front face 701.

[0047] Each fin or vane forming the multi-vane airflow assembly is attached to the back wall 740 of the front face 701 at one end and has a free end with a body between the attached end and the free end. The first fin 703 has a first fin attached end 703’ to the backside 740 of the face, a first fin free end 713 and a body 723. The second fin 705 has a second fin attached end 705’, a second fin free end 715 and a second fin body 725. The third fin 707 has a third fin attached end 707’, a third fin free end 717 and a third fin body 727. The optional vane is attached to the front face at its optional attached end 750’ and has an optional free end 755 with an optional body 752 in between the ends. One or more Bodies have a curvature configured to direct air flow to the predetermined places within said duct.

[0048] The vanes are shown attached at an acute angle (theta) O relative the front face. Also shown is that the acute angle 0 varies between fins or vanes. The variation of the attachment angle, although shown as varying, need not vary in all instances and it is within the scope of this disclosure that the angles may also be the same on all fins or some fins. The curvature of the body of each fin act separately and in concert to shape the airflow and distribute airflow volume to the fuel cells in a fuel cell stack via the ducts. The curvature of each fin is configured to, combined with at least one of the length of each fin and the angle of each fin to direct sufficient airflow to the fuel cells in the first portion of the fuel cell stack 602. Without the ASI we have observed that the first portion of the fuel cell stack receives insufficient airflow (and volume of air) and therefore both produces less power and heats up more than the remainder of the fuel cells stack. Disclosed herein is a method to improve power output in a fuel cell stack comprising hundreds of fuel cells. ASIs disclosed herein evens out airflow to all of the fuel cells forming the stack compared with a fuel cell stack having ducted or manifolds for air which do not utilize air shaping inserts. The evening out of airflow is tuned to optimize power. Although the testing below is with a 432-fuel cell stack, the skilled artisan and those of ordinary skill in the art will recognize the principal of mass airflow shaping and evening out of air flow is the same regardless of adding or subtracting fuel cells forming the stack. Our testing also shows that in a fuel cell stack consisting of 432 fuel cells can produce at least one of 120kW, 125kW, 130kW, 140kW, 145kW, 150kW, 155kW, 160kw, 165kW, and 170kw compared to an output of between 25 and 35kW for the same fuel cell stack without an ASI. The disclosed air shaping insert (ASI) is used to improve heat distribution and power output via a more even mass flow of air. By way of configuring a traditional fuel cell stack with the disclosed air shaping insert (s) between 3.3kWs and 6.8 more kWs are produced by the same fuel cell stack.

[0049] Although fins or vanes may be inserted further than 30% down the duct, our study has demonstrated with the ASI configuration(s) disclosed herein an ASI within the first 30% of the duct improves the distribution of air and the volumetric flow of air between fuel cells and / or modules of fuel cells dramatically. Further the more even distribution of air through the fuel cells forming the fuel cell stack results in higher output of the fuel cell stack. In some instances, depending on the ASI configuration (shape of vanes body, length of fins, curvature and the like) the improvement in power output is at least 150%, in other instances the improvement in power output is at least 200%, in some instances the improvement in power output is at least 250%, in some instances the improvement in power output is at least 300%. In some instances, the improvement in power output is at least 350%. In some instances, the improvement in power output is at least 400%. In some instances, the improvement in power output is at least 450%. In some instances, the improvement in power output is at least 500%. In some instances, the improvement in power output is at least 550%.

[0050] Figure 10 illustrates a four hundred and thirty-two fuel cells stack 650 with a longer ASI 800 which extends further into the duct 601 than shown in previous figures. The length shown is not a limitation and the ASI disclosed in this exemplar can extend down the length of the duct 601. Our tests showed that an extended ASI is less successful at evening mass air flow and improving performance than a single ASI placed as specified above. Our tests showed that extended ASI down at least 90% of the duct reduced the imbalance between the first fuel cell in the stack and the last fuel cell in the stack 100N from approximately 240% with no ASI to approximately 76% with an extended ASI. Further that inserting and positioning such a long ASI in a deep duct proved to be a production limiting step.

[0051] Figure 11 illustrates a four hundred and thirty-two fuel cells stack 650 with multiple ASIs each one affixed at a place down the duct 601 in the stack. The illustration of a four hundred and thirty-two fuel cells stack is not a limitation and those of ordinary skill in the art and the skilled artisan will recognize that the number of fuel cells in a module or a stack is a design choice, and the ASI is agnostic to same. The first ASI 850, the second ASI 852and the third ASI 855 may each be different in one or more of length of vanes or fins, number of fins or vanes, angle of attachments of fins or vanes, and curvature of fins or vanes. Our tests showed that multiple ASI reduce the imbalance between the first fuel cell in the stack 100A and the last fuel cell in the stack 100N from approximately 240% with no ASI to approximately 18% with multiple ASIs. which is less successful at evening mass air flow and improving performance than a single ASI placed as specified above.

[0052] Figure 12 is a graph showing the airflow imbalance among 6 modules forming a four hundred and thirty-two fuel cell stack without an ASI. The illustration of a four hundred and thirty-two fuel cells stack is not a limitation and those of ordinary skill in the art and the skilled artisan will recognize that the number of fuel cells in a module or a stack is a design choice, and the ASI is agnostic to same. The mass airflow at module six nearest the last fuel cell 100N in the stack is about 240% greater than at module one. Therefore, the limited airflow at module 1 increases the temperature of module one and limits the power output of the entire stack by about 5.5 times. In other words while an equivalent fuel cell stack to that described above has been shown to produce a 170KW power output with an ASI optimizing the airflow in the duct, the fuel cell stack without the ASI, described in the bar graph of figure 12, is limited to about 30kW.

[0053] Figure 13 is a graph showing the results of different ASI platforms on airflow imbalance among six modules forming a four hundred and thirty-two fuel cell stack. The mass airflow without an ASI 901 is illustrated. The mass airflow at module six was measured to be most even to the airflow at modules one, two, three, four and five in the configuration labeled “Test Rev. G” 902 which has an ASI deployed. . In Test Rev. G the imbalance between module six and module one was measured at 9%. The imbalance between module six and module two was also measured at 9%. The imbalance between module six and module three was measured at 6.9%. The imbalance between module six and module four was measured at 5%. The imbalance between module six and module five was measured at 2.8%. The mass airflow at all six of the modules was measured to be more less even than Test Rev. G in Test Rev. D. However Test Rev. D even with the configuration roughly illustrated in Figure 11 and labeled in Fig. 13 as “Test Rev. D” 904 than without an ASI as shown in “Test Rev. B” 901. Without an ASI, the imbalance between module six and module one was measured at 240%. The imbalance between module six and module two was measured at 190%. The imbalance between module six and module three was measured at 160%. The imbalance between module six and module four was measured at 139%. The imbalance between module six and module five was measured at 120%.

[0054] While systems and methods have been described in connection with the various embodiments of the various figures, it will be appreciated by those skilled in the art that changes could be made to the embodiments without departing from the broad inventive concept thereof. It is understood, therefore, that this disclosure is not limited to the particular embodiments disclosed, and it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the claims. Also, as used in the specification including the appended claims, the singular forms "a," "an," and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. The term "plurality", as used herein, means more than one. When a range of values is expressed, another exemplar includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about." it will be understood that the particular value forms another exemplar. All ranges are inclusive and combinable.

[0055] It is to be appreciated that certain features of the disclosure which are, for clarity, described herein in the context of separate exemplar, may also be provided in combination in a single exemplary implementation. Conversely, various features of the disclosure that are, for brevity, described in the context of a single exemplary implementation, may also be provided separately or in any sub combination. Further, reference to values stated in ranges include each and every value within that range.

Claims

1. An air shaping insert (ASI) configured to mate with a duct in a fuel cell stack, comprising:a multi-vane airflow assembly forming an air shaping insert (ASI) configured to fit into a duct formed in a fuel cell stack, the assembly comprising;a front face configured to receive airflow;a back wall of the front face configured to support a plurality of vanes;a plurality of vanes affixed at one end to said back wall and each having a free end; wherein said plurality of vanes have differing lengths measured from said backside; wherein one or more of the plurality of vanes have a curvature of their body configured to direct airflow in the duct.

2. The air shaping insert configured to mate with a duct in a fuel cell stack of claim 1, further comprising;a fuel cell stack formed of fuel cells and having at least one air duct configured to accept an ASI; and,wherein the ASI evens out the mass airflow in the duct between fuel cells forming the stack.

3. The air shaping insert configured to mate with a duct in a fuel cell stack of claim 2, further comprising;at least one of the plurality of vanes is split having at least two extended arms and a connector region therebetween configured to form an open region between said extended arms.

4. The air shaping insert configured to mate with a duct in a fuel cell stack of claim 3, further comprising;each arm is attached the back side of the front face and each has a free end;the distance between the two arms at the connector region (dl) is less than the distance between the free ends (d2).

5. The air shaping insert configured to mate with a duct in a fuel cell stack of claim 4, further comprising each arm has a curved top inside edge between the connector region and the free end.

6. The air shaping insert configured to mate with a duct in a fuel cell stack of claim 5, wherein at least one of the open region and curved top edge directs and / or shapes airflow.

7. The air shaping insert configured to mate with a duct in a fuel cell stack of claim 5 or 6, further comprising at least one outside wall (702) formed extended from at least one side edges (712) of the front face to at least one of direct airflow and anchor said plurality of vanes.

8. The air shaping insert configured to mate with a duct in a fuel cell stack of any of claims 5 to 7, further comprising at least one second side wall (706) formed extended from the backside to at least one of direct airflow and anchor said plurality of vanes.

9. The air shaping insert configured to mate with a duct in a fuel cell stack of any of claims 5 to 8, further comprising at least one third side wall (708) formed extended from the backside to at least one of direct airflow and anchor said plurality of vanes.

10. A method to even mass air flow entering a fuel cell stack, the method comprising; inserting a multi-vane airflow assembly configured with a plurality of vanes formingan air shaping insert (ASI) and each having a free end into a duct formed in a fuel cell stack; wherein said plurality of vanes have differing lengths;wherein one or more of the plurality of vanes have a curvature of their body configured to direct airflow in the duct;wherein the ASI evens out the mass airflow in the duct between fuel cells forming the stack.

11. The method to even mass air flow entering a fuel cell stack, of claim 10, wherein; each duct has a front end and a remote end; and, wherein vanes extend between 8% and 30% into the duct from the first end.

12. The method to even mass air flow entering a fuel cell stack, of claim 11, wherein the imbalance of mass airflow between the front end of a duct and the remote end is less than 10%.

13. The method to even mass air flow entering a fuel cell stack, of claim 11 or 12, wherein the imbalance of mass airflow between the front end of the duct and the remote end is less than 9%.

14. The method to even mass air flow entering a fuel cell stack, of any of claims 10 to 13, wherein the fuel cell stack has a plurality of ducts and there is one multi-vane airflow assembly inserted in each duct.

15. The method to even mass air flow entering a fuel cell stack, of claim 12, wherein: the fuel cell stack is configured with 432 fuel cells; and,wherein the output of said fuel cells stack is between about 3.4 and about 6.8 times greater than the fuel cell stack without the ASI.

16. The method to even mass air flow entering a fuel cell stack, of claim 15, wherein the fuel cell stack configured with an ASI produces at least one of 120kW, 125kW, 130kW, 140kW, 145kW, 150kW, 155kW, 160kw, 165kW, and 170kw a; and. the same fuel cell stack without an ASI produces an output of between 25kWs and 35kWs.17

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