Water Separator Within a Fuel Cell Stack

Abstract

A fuel cell system includes means to separate water from the cathode exhaust stream that is integrated into a fuel cell stack for reducing its overall size. Fuel cell assemblies are compressed togethe

Description

TECHNICAL FIELD

[0001] Uiis disclosure generally relates to devices and methods for collecting and separating water from the cathode exhaust of a fuel cell stack. 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] In a fuel cell assembly, each unit, has an anode, a cathode, and an electrolyte (electrolyte membrane). Hydrogen is supplied to tine anode and oxygen containing air is supplied to the cathode. By way of a membrane electrode assembly (MEA) the hydrogen and oxygen produce electricity, heat, and water.

[0004] A stack is formed from a number of such fuel cells arranged with separate anode and cathode fluid flow paths. Such a stack is typically in the form of a block comprising numerous individual fuel cell plates held together by end plates at either end of the stack. It is important that the polymeric ion transfer membrane remains hydrated for efficient operation. 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 directed through flow fields and plates at the fuel cell level and through connected manifolds at the stack level. DISCLOSURE

[0007] This disclosure teaches aspects of smaller footprint fuel cell stacks with evaporative cooling. Vehicle engine compartments tend to be space limited to minimize the size of the engine or power supply compartment. Traditional fuel cell stacks separate water produced during operation in a water separator device outside of the fuel cell stack and as part of the balance of plant.

[0008] The foregoing needs are met by the various aspects of an integrated water separator for fuel cell systems, and methods of use disclosed throughout tins application. According to some aspects of the disclosure a method of water separation in a manifold or duct in a fuel cell stack formed by way of fuel cell assembly frames aligning in a stack with common openings in fluid communication with inputs or outputs of fuel, air, water.

[0009] According to some aspects of the disclosure systems and methods to collect water and separate vapor from liquid within a fuel cells system are disclosed. Aspects of an integrated water separator disclosed include a plurality of fuel cell assemblies configured to be compressed together to form a stack, having a top and bottom. Each fuel cell assembly has one or more frames configured to support assembly electrode assembly (MEA),at least one hydrogen outlet configured to collect hydrogen from the anode side of the MEA, at least one cathode exhaust outlet configured to collect at least air and water from the cathode side of the MEA and wherein the cathode exhaust outlets of the fuel cell assemblies are configured to form a collection cavity in the fuel cell stack fluidly connected to each fuel cells assembly. A water outlet is in fluid communication with the collection cavity and, a water collection means such as a ramp is configured to fit within the collection cavity.

[0010] In some instances a cathode flow field is configured to distribute oxygen from at least one air inlet formed in the frame across the MEA. In some instances a anode flow field is configured to distribute hydrogen from one or more inlets formed in the frame across the MEA. In some instances, at least one gas diffusion layer is adjacent to at least one of the cathode and anode flow fields. In some instances, one or more inlets formed in each frame may be configured to supply gaseous hydrogen to the anode side of the MEA. In some instances, one or more inlets formed in each frame may be configured to supply gaseous air to the cathode side of the MEA. In some instances, one or more inlets formed in each frame may be configured to supply water to at least the cathode side of the MEA.

[0011] According to some aspects of the disclosure systems and methods to collect water and separate vapor from liquid within a fuel cells system are disclosed. Aspects of an integrated water separator disclosed include a plurality of fuel cell assemblies configured to be compressed together to form a stack, having a top and bottom. Each fuel cell assembly has one or more frames configured to support a membrane electrode assembly (MEA), at least one hydrogen outlet configured to collect hydrogen from the anode side of the MEA, at least one cathode exhaust outlet configured to collect at least air and water from the cathode side of the MEA and wherein the cathode exhaust outlets of the fuel cell assemblies are configured to form a collection cavity in the fuel cell stack fluidly connected to each fuel cells assembly. A water outlet is in fluid communication with the collection cavity and, a water collection means such as a ramp is configured to fit within the collection cavity. The collection ramp comprises a first side, a second side, a first edge, a second edge, a top and a bottom and is configured to fit within the collection cavity to collect water from the cathode exhaust. In some instances, gutters extend from at least one side of the ramp.

[0012] In some instances, a spine is affixed longitudinally to at least a portion of the first edge and saw teeth are formed on at least a portion of the second edge. Ihc gutter is affixed at one end to the spine; and water captured on the ramp drips from the gutter to the saw tooth edge. In some instances multiple spine or partial spines are formed on the ramp. In some instance the saw tooth is a wavy edge or a plain edge.

[0013] In some instances at least one of the ramp and gutters lias at least one of texture, bumps, protrusions, divots, channels and grooves.

[0014] In some instances an air manifold is in fluid communication with the collection cavity. In some instances, a top collector is formed as part of or affixed to the inside of the exhaust manifold having fins facing the collection cavity and during operation water collected on the fins is directed to the collection ramp.

[0015] In some instances the outer surface of at least one of the top collector and ramp lias preselected surface lubricity or surface roughness. In some instances, the outer surface of at least one of the top collector and ramp is one of hydrophobic and hydrophilic.

[0016] According to some aspects of the disclosure systems and methods to collect water and separate vapor from liquid within a fuel cells system are disclosed. Aspects of an integrated water separator disclosed include a plurality of fuel cell assemblies configured to be compressed together to form a stack, having a top and bottom. Each fuel cell assembly has one or more frames configured to support a membrane electrode assembly (MEA), at least one hydrogen outlet configured to collect hydrogen from the anode side of the MEA, at least one cathode exhaust outlet configured to collect at least air and water from the cathode side of the MEA and wherein the cathode exhaust outlets of the fuel cell assemblies are configured to form a collection cavity in the fuel cell stack fluidly connected to each fuel cells assembly. A water outlet is in fluid communication with the collection cavity and, a water collection means such as a ramp is configured to fit within the collection cavity. Hie collection ramp comprises a first side, a second side, a first edge, a second edge, atop and a bottom and is configured to fit within the collection cavity to collect water from the cathode exhaust. The collection ramp is affixed in the collection cavity at an angle relative to the floor of the collection cavity. In some instances gutters extend from at least one side of the ramp.

[0017] In some instances, a cathode flow field is configured to distribute oxygen from at least one air inlet formed in each frame across the MEA. In some instances a anode flow field is configured to distribute hydrogen from one or more inlets formed in the frame across the MEA. In some instances at least one gas diffusion layer is adjacent to at least one of the cathode and anode flow fields.

[0018] In operation the above fuel cell system one or more inlets formed in each frame supply gaseous hydrogen to the anode side of the MEA and one or more inlets formed in each frame may be configured to supply gaseous air to the cathode side of the MEA. Further one or more inlets formed in each frame may be configured to supply water to at least the cathode side of the MEA and the water collection means further comprises a body portion having an outer surface configured to fit within the collection cavity and is configured to collect water from the cathode exhaust.

[0019] According to some aspects of the disclosure a system and method to adjust collected water and separate vapor from liquid within a fuel cells system are disclosed including, a plurality of fuel cell assemblies configured to be compressed together to form a stack, having atop and bottom. Each fuel cell assembly has one or more frames configured to support a membrane electrode assembly (MEA),at least one hydrogen outlet configured to collect hydrogen from the anode side of the MEA, at least one cathode exhaust outlet configured to collect at least air and water from the cathode side of the MEA and wherein the cathode exhaust outlets of the fuel cell assemblies are configured to form a collection cavity in the fuel cell stack fluidly connected to each fuel cells assembly. A water outlet is in fluid communication with the collection cavity and, a water collection means is configured to have a ramp that fits within the collection cavity. In some instance the ramp has one or more of fins, bumps, protrusions, divots, channels, and grooves. In some instances, the ramp is multipart. In some instances, the ramp lias at least one of preselected surface lubricity and surface roughness. In some instances, the ramp is one of hydrophobic and hydrophilic. In some instances, the ramp portion has at least one region which is more hydrophilic or more hydrophobic than other parts of the outer surface. In some instances, the ramp has both a hydrophilic and hydrophobic region. In some instances, the ramp has at least some areas that are textured and in other instances the ramps are without textured.

[0020] In some instances, an exhaust outlet head is added and in fluid communication with the collection cavity. In some instances, a fan in fluid communication with the collection cavity and within the water collection means is added. FIGURES

[0021] 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. In the drawings:

[0022] Fig. 1 is a flow diagram of aspects of the operation of an internal water separator in a fuel cell stack.

[0023] Fig. 2 is a stack of fuel cell assemblies.

[0024] Fig. 3 is atop view of some aspects of a fuel cell assembly.

[0025] Fig. 4 is an exploded view of the assembly of a fuel cell system with an internal water separator.

[0026] Fig. 5 A is an assembled view of a fuel cell system with an internal water separator.

[0027] Fig. 5B is a partially assembled view of a fuel cell system with an internal water separator, illustrating multiple water outlets.

[0028] Fig. 6A is a cutaway illustration of an assembled fuel cell system illustrating aspects of the integrated water separator.

[0029] Fig. 6B is a front view of aspects of a water collection ramp of the fuel cell system with an internal water separator of Fig. 4.

[0030] Fig. 6C is a cut away view of the collection ramp of figure 6B along the line A-A.

[0031] Fig. 6D is a bottom view of aspects of an additional top collector which may be part of an integrated water separator. FURTHER DISCLOSURE

[0032] By integrating water separation of the exhausted water from the cathodes of the fuel cell assemblies in a fuel cell stack, this disclosure teaches the use or capture of previously lost manifold space to functional water separation. A smaller footprint fuel cell power system occupies less volume when mounted in a vehicle or other application. In some instances, the integrated water separator is less complex by way of utilizing the manifold as a portion of the encasement for the water separator.

[0033] Figure 1 illustrates a flow diagram of the operation of a fuel cell stack with integrated water separator 10. Fuel and air (oxidant) 12 are fed into the fuel cell stack 13. As needed liquid coolant 14 such as water is fed into the fuel cell stack to be distributed to the fuel cells therein. The products of the electrochemical reaction which takes place in the fuel cell are the production of electricity (power), heat, and water vapor and liquid 16. The water vapor and liquid are collected inside the fuel cell stack by way of flow channels or other fluid connection from each fuel cell forming the fuel cell stack to a stack collection location or manifold. The present disclosure teaches the integration of a water separation device or means to collect water and then separate 18 vapor from liquid. Water vapor and other cathode air is exhausted 20 from the stack. The collected liquid water 30 is one of distributed to the fuel cell stack 31 and stored 32 then distributed 33 to the fuel cell stack for humidification and cooling.

[0034] Figures 2-7 integrating water separation into a fuel cells stack. The fuel cell stack 100 is formed by stacking a plurality of fuel cell assemblies 115 / 115 (1-N) each supporting a membrane electrode assembly (MEA) 150 and having gaskets and bipolar plates. Normally flow fields (not shown) will be formed in the bipolar plates, and gas diffusion layers will be sandwiched between the MEA and cathodes and anodes. Not shown are gaskets and seals which are formed on the frame to seal the fuel cell assemblies into a stack with only predetermined manifolds and / or and fluid pathways.

[0035] Figure 3 shows a top view of a fuel cell assembly 115 showing inlets and outlets formed in the frame. At a first end of the fuel cell assembly there is at least one water inlet 160, at least one air inlet 162 and at least one hydrogen exhaust outlet 164. At a second end is at least one hydrogen inlet 166 and one or more air exhausts 168 from the cathodes. A water outlet is 170 also shown and it is in fluid contact with the air exhaust 168 region or manifold. Optionally one or more additional manifolds 175 may be provided. One or more arrays of fluid pathways or connections 180 are formed at the first end and provide fluid communication to the flow fields below. One or more arrays of fluid pathways or connections 185 are formed at the second end and provide fluid communication with the flow fields below.

[0036] Figures 4-5B shows aspects of assembled fuel cell stack in a fuel cell system 200. In Fig. 4 the fuel cell stack’s bottom 102 and top 104 are called out. The fuel cell stack is shown compressed between a first end plate 201 covering the bottom 102 and a second end plate 210 covering the top 104. The designation of top and bottom is for convenience only and does not denote orientation. The end plates and the fuel cell stack are configured to fit together. A plurality of fasteners 212 are commonly used to further compress the fuel cell to assure all of the fuel cell assemblies seal together and do not leak. Fastening fuel cell stack and systems together is known in tire art. Fastener 212 passes through both the first and second end plates and are secured by nuts 213 (shown in Fig. 5A) or similar connection means.

[0037] The second end plate 210 has passages which align with the water inlet, air inlet, hydrogen exhaust outlet, hydrogen inlet and exhaust from the cathodes. The water inlet passage 220 is fluidly connected to the at least one water inlet 160, the air inlet passage 222 is fluidly connected to the air inlet 162, the hydrogen outlet passage 226 is fluidly connected to the hydrogen outlet 164. Hie hydrogen inlet passage 236 is fluidly connected to the hydrogen inlet 166. The air exhaust 168 is fluidly connected to the exhaust passage 238. The water outlet 170 whereby liquid water is removed from the stack is also fluidly connected to the exhaust passage 238. The air exhaust duct or manifold 250 is in fluid communication with the collection cavity 300. An integrated water separator. In some instances the top collector 400 is formed as part of or affixed to the inside of the air exhaust manifold. The water collection ramp 252 fits into through air exhaust of each fuel cell assembly and the collection cavity formed by said air exhaust (168) of each fuel cell assembly. The ramp has a top 253 and a bottom 254. The air exhaust manifold has a body portion 260 and an outlet head 265. The outlet head is configured to be attachable in a variety of configurations to direct the open end 270 in a predetermined direction, from up to down to left and right and any direction in between which is at least partially outside of the fuel cell stack. Those of ordinary skill in the art, and the skilled artisan will recognize that the entire water separator may also fit within the collection cavity without departing from the scope of the disclosure.

[0038] Figures 5A and 5B show aspects of an assembled fuel cell system 200 with integrated water separator. Those of ordinary skill in the art and the skilled artisan will recognize that the dimensions of a fuel cell assembly may vary widely depending on the intended use and that the number of assemblies forming a stack may vary. However, these design variations will have common features that are within the scope of this invention. They will have a manifold of fluidly connected region through the plurality of fuel cell assemblies and that region will be configured for insertion of a water separation means. Fasteners 212 are commonly used to compress or maintain a compressed state for the fuel cell assemblies in tine fuel cell system.

[0039] In operation hydrogen inlet 166 receives a feed of gaseous hydrogen fuel which is distributed to the anodes of the bipolar plates of each fuel cell assembly and the unspent hydrogen exists at the hydrogen outlet 164. Air is supplied through the air inlet 162 to the cathode side of the bipolar plates of each fuel cell assembly. Water is supplied to the fuel cell assemblies through the water inlet 160 and removed as liquid water and water vapor through the air exhaust 168. When stacked the fuel cell assemblies air exhausts form a collection cavity 300 for removing water and water vapor from the fuel cell stack. Collected liquid water may be removed via the one or more water outlet 170. Said water can be recycled to the fuel cell stack for cooling and humidification as needed.

[0040] Figures 6A-6D illustrates the internal water separator with a collection ramp 252 configured to fit into the collection cavity 300 formed by the plurality of air exhausts of each of the stacked fuel cell assembly. The collection ramp at least one of collects, captures, condenses, cools, and redirects water exiting the cathode flow fields of each fuel cell assembly as cathode exhaust and urges the water via gravity and surface tension towards the bottom 102 of the fuel cell stack. The collection ramp or parts thereof (including gutters) may be a plate or plates, may be porous or textured to capture and move water. The collection ramp or parts thereof (including gutters) may have surface features including but not limited to one or more of fins, bumps, protrusions, divots, channels or grooves to direct the water captured. The collection ramp or parts thereof (including gutters) may be multi part and be constructed of non-homogeneous materials. The materials may be homogeneous in lubricity, smoothness or roughness, or they may be non-homogeneous for same. The material may have antimicrobial and antibacterial agents embedded therein or surface features which resist bacterial, algae and microbial growth. One side of the collection ramp may have a different set of features including but not limited to texture, smoothness, lubricity and / or grooves, channels, dimples, divots and the like than the other side.

[0041] In some instances, the collection ramp or parts thereof (including gutters) is hydrophilic. In some instances, the collection ramp or parts thereof (including gutters) has both hydrophilic and hydrophobic areas. In some instances, the collection ramp or parts thereof (including gutters) can act as a heat sink for the liquid water and water vapor in the air exhaust to further urge condensation.

[0042] The collection ramp 252 has a first side 402 and a second side 404. One side faces the exhaust coming off each fuel cell assembly and the other side is opposite that exhaust. Raised gutters 405 may be formed on one or both of the first and second sides. Although the gutters are shown attached to a spine 410 at a first gutter end 412 and with an unattached second gutter end 414, those of ordinary skill in the art and the skilled artisan will recognize that the first gutter end may be unattached to the spine. They will also recognize that the angle of the gutter relative to the spine, as shown in the illustration is not a limitation and the disclosure’s scope includes varying the angle of all the gutters relative to the spine or of a portion of the gutters. The disclosure also includes variable angled gutter arrays wherein different gutters have different angles relative to the spine. Differing angles will in turn have varied rate of flow of water captured by the gutters. The ramp may be tuned to address fluid volume and flow rate of exhaust from the plurality of fuel cell assemblies each adding heated exhaust into the collection cavity with the heated exhaust rising from the bottom of the fuel cell 102 towards the top 104. Additional ramps may be inserted with a separation between them. Those of ordinary skill in the art and the skilled artisan will recognize that one or more additional spines may run the length of all or part of the ramp and such modifications are within the scope of this disclosure.

[0043] In some instances the gutters have perforations, do not extend the width of the gutter or are gapped walls. In other instance the gutters are at least partially wavy or undulating and not straight. The angle 420 of the bottom of the ramp 254 to the floor 302 of the collection cavity is fixed in a predetermined configuration. The angle of the ramp is tuned for the impaction of heated exhaust from the plurality of fuel cell assemblies each fluidly connect to the collection cavity with heated air, water and water vapor flowing into the collection cavity. The angulation can be tuned to reduce any pressure differential among the fuel cell assemblies in the stack due to the location of the fuel cell assembly relative to the top or bottom of the fuel cell stack. Accordingly, those of ordinary skill in the art and the skilled artisan will recognize that if the type of number of fuel cell assemblies change or the volume of air exhausted is different the angulation may be changed and that change would be within the scope of this disclosure.

[0044] The gutter in in some instances lias a jagged or sawed tooth edge 430 opposite the spine 410. The gutter is depicted as “L” shaped with a first leg 412 connected to the collection ramp and a second leg 414 connected to the first leg and with a free end 415. During operation the method is that the free end 415 which is configured to direct captured water to the jagged edge 430 acts to direct water towards the free end. The water directed to the jagged end 430 drips in the predetermined area aligned with the jagged end 430 for collection. Those of ordinary skill in the art and the skilled artisan will recognize that an “L” shape is not a limitation rather it is a depiction of. A collection area that directs water on the ramp to a predetermined location. Said gutters could be 'CU” shaped or "V" shaped or any of a plethora of shapes that direct and collect water and such shape gutters would be within the scope of the disclosure. The gutters are configured to also increase surface area of the collection ramp thereby providing more opportunity to collect water. Those of ordinary skill in the art and the skilled artisan will recognize that the saw tooth is a depiction and that a curvy edge or a straight edge in place of the sawtooth is within the scope f the disclosure. Moreover the same tooth edge shown running the length of the ramp is not a limitation and inn some instances it may traverse only a portion of the length of the ramp.

[0045] Optionally a top collector 450 is formed as part of or affixed to the exhaust body portion 260. The top collector has a collection cavity facing surface 452 from which ridges or fins 455 extend, the extended fins 455 are configured to have additional surface area to collect water in the air water, water vapor exhaust and direct the captured water downward to the collection ramp. The ridges or fins 455 in some instances have one or more of protrusions, divots, channels and grooves thereon. In some instances the fins 455 are multipart. In some instances the fins have at least one of preselected surface lubricity and surface roughness. In some instances the fins are one of hydrophobic and hydrophilic. In some instances the fins has at least one region which is more hydrophilic or more hydrophobic then other parts. In some instances the fins have both hydrophilic and hydrophobic regions. In some instances the fins has at least some areas that are textured and in other instances the fins are textured.

[0046] The method disclosed herein is a method to repurpose wasted manifold spaces in a fuel cell stack to act as a containment for a water separator to reduce the footprint of the fuel cell system. Using the fuel cell as a containment also simplifies the water separator and reduce the cost and complexity of the water separator.

[0047] The systems described throughout this disclosure can be utilized in a variety of applications for providing power generated by fuel cell systems. In some aspects, the systems disclosed throughout this application can be used in machine handling equipment such as a forklift. In some aspects, the systems can be used in an unmanned aerial vehicle (UAV), such as a fixed or multi-rotor drones. In some aspects, the systems disclosed herein can be used in automotive applications, such as in cars. In some aspects, the systems disclosed herein can be used in stationary power applications. In some aspects, the systems disclosed herein can be used in aviation. It will be appreciated that the systems can be used in a variety of other applications, and the certain functional and physical parameters, such as component sizes and quantities, may be varied for specific applications and may be dictated by requirements for specific uses. Additional advantages to those described above include being able to fit the systems and related components (such as fuel cannister cylinders) into smaller spaces and to arrange systems and related components.

[0048] The components disclosed herein may utilize known materials that are used in the industry.

[0049] Throughout this specification, words are to be afforded their normal meaning as would be understood by those skilled in the relevant art. However, so as to avoid misunderstanding, the meanings of certain terms will be specifically defined or clarified.

[0050] While the disclosure has 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 described above 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.

[0051] Features of the disclosure that are described above in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, various features of the disclosure that are described in the context of a single embodiment may also be provided separately or in any sub-combination. Finally, while an embodiment may be described as part of a series of steps or part of a more general structure, each said step may also be considered an independent embodiment in itself, combinable with others.

[0052] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[0053] Further features and aspects of the invention may reside in the following clauses: CLAUSES 1. A fuel cell system comprising: a plurality of fuel cell assemblies configured to be compressed together to form a stack, having a top and bottom, each fuel cell assembly comprising; one or more frames configured to support a membrane electrode assembly (MEA); at least one hydrogen outlet configured to collect hydrogen from the anode side of the MEA; at least one cathode exhaust outlet configured to collect at least air and water from the cathode side of the MEA; wherein the cathode exhaust outlets of the fuel cell assemblies are configured to form a collection cavity having a floor in the fuel cell stack fluidly connected to each fuel cells assembly; a water outlet is in fluid communication with the collection cavity; and, A collection ramp is configured to fit within the collection cavity. 2. The fuel cell system of clause 1 further comprising a cathode flow field configured to distribute oxygen from at least one air inlet formed in the frame across the MEA. 3. The fuel cell system of clause 1 further comprising a anode flow field configured to distribute hydrogen from one or more inlets fonued in the frame across the MEA. 4. The fuel cell system of clause 1 further comprising at least one gas diffusion layer adjacent to at least one of the cathode and anode flow fields. 5. The fuel cell system of clause 1 further comprising one or more inlets formed in each frame configured to supply ydrogen to the anode side of the MEA. 6. The fuel cell system of clause 1 further comprising one or more inlets formed in each frame configured to supply gaseous air to the cathode side of the MEA. 7. The fuel cell system of clause 1 further comprising one or more inlets fonned in each frame configured to supply water to at least the cathode side of the MEA. 8. The fuel cell system of clause 1 wherein the collection ramp further comprises a first side, a second side, a first edge, a second edge, a top and a bottom and is configured to fit within the collection cavity to collect water from the cathode exhaust. 9. The fuel cell system of clause 8 further comprising gutters extending from at least one side of the ramp. 10. The fuel cell system of clause 9 further comprising: a spine that is affixed longitudinally to the first edge; saw tooth teeth formed on the second edge; wherein the gutter is affixed at one end to the spine; and, wherein water captured on the ramp drips from the gutter to the saw tooth edge. 11. The fuel cell system of clause 9 wherein at least one of the ramp and gutters has at least one of texture, bumps, protrusions, divots, channels and grooves. 12. The fuel cell system of clause 1 further comprising an air manifold in fluid communication with the collection cavity. 13. The fuel cell system of clause 1 further comprising: a top collector formed as part of or affixed to the inside of the exhaust manifold configured to have fins facing the collection ca\ ih inside the exhaust manifold; and, wherein during operation water collected on the fins is directed to the collection ramp. 14. The fuel cell system of clause 1 or 13 wherein the outer surface of at least one of the top collector and ramp has preselected surface lubricity or surface roughness. 15. The fuel cell system of clause 1 or 13 wherein the outer surface of at least one of the top collector and ramp is one of hydrophobic and hydrophilic. 16. The fuel cell system of clause 8 wherein the ramp is affixed in the collection cavity at an angle relative to the floor of the collection cavity. 17. A method to separate water in a fuel cell system integrated into a fuel cell stack, the method comprising: compressing a plurality of fuel cell assemblies together to form a fuel cell stack; aligning the cathode exhaust outlets of the fuel cell assemblies to form a collection cavity in the fuel cell stack fluidly connected to each fuel cells assembly; placing a water outlet in fluid communication with the collection cavity; and, placing a water collection ramp in the collection cavity.

Claims

1. A fuel cell system comprising:a plurality of fuel cell assemblies configured to be compressed together to form a stack, having a top and bottom, each fuel cell assembly comprising:one or more frames configured to support a membrane electrode assembly (MEA);at least one hydrogen outlet (164) configured to collect hydrogen from the anode side of the MEA;at least one cathode exhaust outlet (168) configured to collect at least air and water from the cathode side of the MEA;wherein the cathode exhaust outlets (168) of the fuel cell assemblies are configured to form a collection cavity (300) having a floor in the fuel cell stack fluidly connected to each fuel cell assembly;a water outlet (170) is in fluid communication with tire collection cavity (300);and,wherein the water collection ramp (252) is configured to fit within the collection cavity (300);wherein the water collection ramp (252) further comprises a first side, a second side, a first edge, a second edge, a top and a bottom and is configured to fit within the collection cavity (300) to collect water from the cathode exhaust; andwherein the fuel cell system further comprises:gutters extending from at least one side of the water collection ramp (252);a spine that is affixed longitudinally to the first edge;saw tooth teeth formed on the second edge;wherein the gutter is affixed at one end to the spine; and, wherein water captured on the water collection ramp (252) drips from the gutter to the saw tooth edge.

2. Tire fuel cell system of Claim 1, further comprising a cathode flow field configured to distribute oxygen from at least one air inlet formed in the frame across the MEA.

3. The fuel cell system of any preceding claim, further comprising an anode flow field configured to distribute hydrogen from one or more inlets formed in the frame across the MEA.

4. The fuel cell system of any preceding claim, further comprising at least one gas diffusion layer adjacent to at least one of the cathode and anode flow fields.

5. The fuel cell system of any preceding claim, further comprising one or more inlets formed in each frame configured to supply hydrogen to the anode side of the MEA.

6. The fuel cell system of any preceding claim, further comprising one or more inlets formed in each frame configured to supply gaseous air to the cathode side of the MEA.

7. The fuel cell system of any preceding claim, further comprising one or more inlets formed in each frame configured to supply water to at least the cathode side of the MEA.

8. The fuel cell system of Claim 1, wherein at least one of the water collection ramp (252) and gutters has at least one of texture, bumps, protrusions, divots, channels and grooves.

9. The fuel cell system of any preceding claim, further comprising an air manifold in fluid communication with the collection cavity.

10. The fuel cell system of any preceding claim, further comprising:a top collector formed as part of or affixed to the inside of the exhaust manifold configured to have fins facing the collection cavity inside the exhaust manifold; and, wherein during operation water collected on the fins is directed to the collection ramp.

11. The fuel cell system of any preceding claim, wherein the outer surface of at least one of the top collector (450) and water collection ramp (252) has preselected surface lubricity or surface roughness.

12. The fuel cell system of any preceding claim, wherein the outer surface of at least one of the top collector (450) and water collection ramp (252) is one of hydrophobic and hydrophilic.

13. The fuel cell system of Claim 8, wherein the water collection ramp (252) is affixed in the collection cavity (300) at an angle relative to the floor of the collection cavity (300).

14. A method to separate water in a fuel cell system integrated into a fuel cell stack, the method comprising:compressing a plurality of fuel cell assemblies together to form a fuel cell stack;aligning cathode exhaust outlets (168) of the fuel cell assemblies to form a collection cavity (300) in the fuel cell stack fluidly connected to each fuel cell assembly;placing a water outlet (170) in fluid communication with the collection cavity (300); and,placing a water collection ramp (252) in the collection cavity (300);wherein the water collection ramp (252) further comprises a first side, a second side, a first edge, a second edge, a top and a bottom and is configured to fit within the collection cavity (300) to collect water from the cathode exhaust; andwherein the fuel cell system further comprises:gutters extending from at least one side of the water collection ramp (252);a spine that is affixed longitudinally to the first edge;saw tooth teeth formed on the second edge;wherein the gutter is affixed at one end to the spine; and,wherein water captured on the water collection ramp (252) drips from the gutter to the saw tooth edge.

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