Fuel cell humidification device

Abstract

An embodiment provides a fuel cell humidifier. The embodiment of the fuel cell humidifier includes a stack of unit cells. Each unit cell includes a peripheral frame, a separator having first and second major surfaces, a first membrane sheet bonded to the peripheral frame at the first major surface of the separator, and a second membrane sheet bonded to the peripheral frame at the second major surface of the separator. The peripheral frame and the first and second membrane sheets define a cavity within the peripheral frame. Opposing first and second frame ends of the peripheral frame are open to allow a first flow in a first direction through the cavity. The separator has first and second ridges extending across the first and second frame ends, respectively. In a stack of unit cells, the first and second ridges contact the separators of adjacent unit cells, thereby separating the unit cells from each other and providing passages extending through the stack of unit cells in a second direction intersecting the first direction. In some embodiments, the unit cells can all be stacked in the same orientation.

Description

Technical Field

[0001] This application claims the priority of U.S. Patent Application No. 63090028, filed on October 9, 2020, the title of the invention being Fuel Cell Humidification Device, which is incorporated herein by reference in its entirety for all purposes. For the United States, this application claims the benefit of 35 U.S.C. § 119 to U.S. Patent Application No. 63090028, filed on October 9, 2020, the title of the invention being Fuel Cell Humidification Device.

[0002] The present invention relates to a membrane-based gas exchange system. Certain embodiments provide a humidification device. The present invention can be embodied, for example, in a humidification device for a fuel cell.

Background Art

[0003] Gases can be exchanged through a membrane that separates two flows. For example, a humidification device can have a membrane that can separate a flow of air or other gas with a higher humidity into a second flow of air or other gas with a lower humidity. Water vapor can be transported through the membrane from the higher humidity flow to the lower humidity flow, thereby humidifying the lower humidity flow.

[0004] In many applications, it is desirable to provide a sufficient membrane surface area while making the gas exchange system relatively compact and achieving the desired gas transfer. This can be achieved with a flat membrane humidification device having a plurality of gas distribution layers separated by a membrane. Each layer may carry one flow. The flows may be parallel to each other (e.g., in a "counter-flow" arrangement) or cross each other (e.g., in a "cross-flow" arrangement).

[0005] Membrane humidifiers include flat membrane or hollow fiber membrane type humidifiers. In hollow fiber humidifiers, the membrane is provided in the form of hollow fibers. The hollow fibers are tubular and have internal channels extending along them. The walls of the hollow fibers function as a functional membrane. Multiple hollow fibers are typically gathered into a fiber bundle and enclosed within a housing. Holes and partitions are provided to direct airflow into the fiber bundle. In a hollow fiber humidifier, one airflow flows through the inside of the fibers, and the other airflow is directed towards the outside of the fibers.

[0006] In flat-film humidifiers, the film is often deposited using a continuous roll-to-roll process. The flat film layer is then combined with a flow-field plate to create a film core. The core is then mounted within a housing to direct the airflow through it. Depending on the design of the humidifier core, the airflow through the core may be direct-to-alternating, counter-to-alternating, or in various other geometric configurations.

[0007] Airflow distribution is crucial in membrane humidifiers. If the airflow is not uniformly distributed across the entire membrane surface, the efficiency of the humidifier decreases. In hollow fiber bundles, achieving a uniform airflow distribution outside the fibers of the bundle is difficult. In flat membrane designs, the flow field is typically well defined across consistent membrane spacing and all membrane surfaces, providing a more uniform airflow distribution. Therefore, flat membrane humidifiers tend to have better vapor transport performance per unit area, allowing for more efficient use of the humidifier's membrane area. Furthermore, hollow fiber membranes tend to be more expensive per unit area than flat membranes. Overall, flat membrane humidifiers can achieve similar performance to hollow fiber humidifiers using less membrane and at a lower cost. Additionally, flat membrane designs can achieve the same performance as equivalent hollow fiber humidifiers with a smaller geometric volume, even when hollow fiber membranes typically have high membrane packing density.

[0008] The flow distribution in the flat membrane design can be well defined, and liquid water can be easily discharged from the flow path of a typical flat membrane humidifier. As a result, flat membrane humidifiers have lower pressure loss due to airflow in the flow path compared to hollow fiber designs, which reduces energy consumption by the compressor, blower, or other devices used to move air through the humidifier.

[0009] One drawback of flat membrane designs compared to hollow fiber designs is that the flow field plate is an extra component of the humidifier, adding to the cost. Another issue with flat membrane designs over hollow fiber designs is that flat membrane designs generally have more sealing surfaces that must meet tighter manufacturing tolerances and be robust throughout the lifespan of the humidifier.

[0010] Manufacturing flat-membrane humidifiers in a cost-effective and reliable manner, while providing a secure seal and preventing airflow mixing by allowing species (e.g., water vapor) to move through the membrane, can be a critical challenge.

[0011] One important application of humidifiers is in the field of fuel cells. Fuel cells can be used to provide power for a wide variety of applications. One area where fuel cells are particularly promising is the field of electric vehicles.

[0012] A fuel cell typically has a membrane electrode assembly, in which a membrane electrolyte selectively permeates ions. Fuel is supplied to a first side of the membrane electrode assembly, and an oxidizer is supplied to a second side of the membrane electrode assembly. The fuel undergoes an electrochemical half-reaction at the first electrode, and the oxidizer undergoes an electrochemical half-reaction at the second electrode. At least one of these half-reactions passes through the membrane electrolyte, releasing ions involved in the other half-reaction. The combined electrochemical reaction creates a potential difference between the first and second electrodes, and can supply current to a load.

[0013] For example, a fuel cell can use hydrogen gas (H2) as fuel and oxygen (which may be oxygen from the air) as an oxidizer. Hydrogen can undergo the following reactions: H2→2H + +2e - Electrons can be used to supply current to a load. Membrane electrolytes are not conductive to electrons. Protons (H+ ions) pass through membrane electrolytes, but in membrane electrolytes, protons are involved in the oxygen molecule in the following reaction. O2+4e - +4H + →2H2O Different fuel cells may use other suitable fuels and / or oxidizers.

[0014] Many of the best membranes used in fuel cells require hydration. Such membranes may, for example, have ionomer polymers that absorb water and / or transport water molecules along with ions (generally protons) that participate in electrochemical reactions. The performance of such membranes in fuel cells can be significantly reduced if the membrane dries out. Membranes are more likely to dry out (be dehydrated) as the operating temperature increases. However, the overall efficiency of a fuel cell can be improved by operating it at higher temperatures, at which point the fuel cell membrane electrolyte may be dehydrated. An example of a membrane that can be used as an electrolyte in a fuel cell is the Nafion® membrane. Polymer electrolyte membrane fuel cells (PEMFCs) are an example of fuel cells that use such membranes.

[0015] To prevent dehydration of the fuel cell, water may be delivered along with the fuel and / or oxidizer supplied to the fuel cell. For example, a flow of oxygen (or air) may be passed through a humidifier that introduces water into the flow. The water, along with the oxygen or air, is then delivered to the fuel cell membrane electrolyte.

[0016] Because water is produced in the fuel cell as part of the fuel cell reaction, the cathode exhaust gas of a PEMFC is often relatively hot, contains a lot of moisture, and has high relative humidity. This exhaust flow is typically depleted of oxygen consumed as reactants in the fuel cell reaction. A fuel cell humidifier can be used to capture moisture from the fuel cell cathode exhaust flow and return it to the fuel cell cathode feed flow.

[0017] In a membrane fuel cell humidifier, the fuel cell cathode exhaust flow, which is enriched with moisture and depleted of oxygen, is directed towards one surface of the membrane, while the dry, oxygen-rich fuel cell cathode air supply is directed towards the opposite surface of the membrane. The membrane selectively allows water vapor to move through it, but prevents mixing of nitrogen and oxygen with the supply and exhaust gas flows. Therefore, the membrane humidifier functions as a passive device, allowing moisture from the fuel cell exhaust flow to be returned to the fuel cell cathode supply flow.

[0018] A durable and cost-effective fuel cell humidification system is needed. [Overview of the project]

[0019] The present invention has several embodiments. These are not limited to, A. Humidifier and humidifier core, for example, a device for humidifying fuel cell reaction fluid. B. Replaceable core (or cartridge) for humidifiers. C. Separators for fuel cell humidifiers or other membrane gas exchange devices. D. Method for manufacturing a fuel cell humidifier or other membrane gas exchange device. It has.

[0020] One aspect of the present invention provides a humidifier having a stack of unit cells. Each unit cell has an outer frame and a separator having first and second main surfaces. The first membrane sheet is joined to the outer frame at the first main surface of the separator, and the second membrane sheet is joined to the outer frame at the second main surface of the separator. The outer frame and the first and second membrane sheets define a cavity inside the outer frame. Opposing first and second frame ends of the outer frame are open so that a first flow can flow through the cavity in a first direction, and the separator has first and second ridges extending across the first and second frame ends, respectively. In a stack of unit cells, the first and second ridges, by contacting the separators of adjacent unit cells, separate the unit cells from each other and provide lateral passages extending through the stack of unit cells in a second direction intersecting the first direction. In some embodiments, the overall height of the stack of unit cells is determined by the heights of the first and second ridges and the thickness of the separators.

[0021] In some embodiments, the first and second ridges are positioned inward from the outer edges of the first and second frame ends, respectively. In such embodiments, the portion between the first ridge of the first frame end and the outer edge of the first frame end may be separated from each other in the laminate of unit cells by a first gap, and the first gap has a material (e.g., adhesive and / or sealant) that bonds adjacent unit cells together. The material may be, for example, a UV-curable adhesive. In some embodiments, the frames are joined together or joined together and sealed by a welding process such as laser or thermal welding.

[0022] In some embodiments, the portion between the second ridge of the second frame end and the outer edge of the second frame end is separated from each other in the stack of unit cells by a second gap, and the second gap has a material (e.g., an adhesive and / or a sealant) for bonding adjacent unit cells.

[0023] In some embodiments, the first and second ridges are respectively present on the first and second opposing surfaces of the separator. The separator is respectively symmetric with respect to a 180-degree rotation about a horizontal axis centered in the separator. The separator optionally has a third ridge on the first frame end of the second surface of the separator, and the outer edge of the third ridge is aligned with the inner edge of the first ridge. When present, the third ridge has a height measured from the side surface of the outer peripheral frame that is smaller than, for example, the height of the second ridge measured from the side surface of the outer peripheral frame.

[0024] In some embodiments, the first and second membrane sheets respectively have a porous substrate and a water vapor permeable coating on one surface of the porous substrate. The first and second membrane sheets may be positioned such that the water vapor permeable coatings face away from the separator to which the first and second membrane sheets are attached. In some embodiments, the porous substrate has polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polypropylene (PP), or other suitable plastics.

[0025] In some embodiments, the separator has PPS, PET, PP, or other plastics. In some embodiments, the plastic separator is overmolded with another material (e.g., another plastic). For example, the porous substrates of the first and second membrane sheets and the substrate may have PPS plastic.

[0026] In some embodiments, the membrane and the porous substrate of the spacer have the same plastic material or the same plastic material of the same polymer family (e.g., PPS, PET, PP, or other plastics). The bonding of the membrane sheet to the separator may involve adhering the plastic material of the membrane sheet to the same plastic material of the separator.

[0027] In some embodiments, the first and second membrane sheets are joined to the separator around the cavity (e.g., wrapped around the outer peripheral frame of the separator and adhered to the separator). In some embodiments, the joining seals the membrane sheet to the separator around the cavity.

[0028] In different exemplary embodiments, the membrane sheet may be made of a membrane material having any of various structures. In some embodiments, the membrane sheet has a multilayer membrane material. For example, the membrane material may have a support layer (such as a layer of non-woven fiber polymer material), a microporous layer, and a water vapor-selective air-impermeable coating layer. In some embodiments where the membrane sheet has a support layer, the separator may be adhered to the support layer of the membrane sheet.

[0029] Some embodiments have a membrane sheet of a membrane material having, or consisting of, a microporous layer and, adjacent thereto, a water vapor-selective coating layer of the microporous layer. In some embodiments where the membrane sheet has a microporous layer, the separator may be adhered to the microporous layer of the membrane sheet.

[0030] Some embodiments have a membrane sheet of a membrane material having one or more additional layers. For example, a surface treatment may be applied to a selected layer of the membrane material.

[0031] In some embodiments, the membrane sheet has a membrane material in which two microporous layers are attached to opposite faces of a selected layer such that the selected layer is disposed between the two microporous layers. The support layer is optionally provided on one or both sides of the membrane material.

[0032] In some embodiments, the membrane sheet has a membrane material in which a support layer is bonded between two microporous layers, and a selective coating is applied to one of the surfaces of the microporous layers. In some embodiments, the surface of the selective layer of the membrane sheet is bonded to a separator.

[0033] In some embodiments, the humidifier has a plurality of flow field elements extending across the cavity between the first and second frame ends. The flow field elements are spaced apart to define a passage extending across the cavity. Opposing faces of the flow field elements may be coplanar with the first and second main faces of the separator. In some embodiments, adjacent flow field elements are spaced apart from each other by a distance ranging from 1 to 5 mm. Part or all of the separator optionally has a plurality of lateral supports that extend between adjacent flow field elements and are dimensioned so as not to obstruct the passage. In some embodiments, the first and second frame ends are formed to provide a plurality of openings that extend through the first and second frame ends and open into corresponding passages, respectively. The openings are optionally formed to have drafted walls.

[0034] In some embodiments, the cavity has a width-to-length aspect ratio ranging from 1:1.2 to 1.2:1.

[0035] In some embodiments, the lateral passage has a height greater than the thickness of the portion of the outer frame to which the first membrane sheet is bonded.

[0036] In some embodiments, the humidifier has a frame surrounding a stack of unit cells, and the frame is stretched to apply compression to the stack of unit cells.

[0037] Another aspect of the present invention provides a unit cell for a humidifier. The unit cell comprises an outer frame and a separator having first and second main surfaces. A first membrane sheet is bonded to the outer frame at the first main surface of the separator, and a second membrane sheet is bonded to the outer frame at the second main surface of the separator. The outer frame and the first and second membrane sheets define a cavity within the outer frame. Opposing first and second frame ends of the outer frame are open so that a first flow can flow through the cavity in a first direction. The separator has first and second ridges extending across the first and second frame ends, respectively.

[0038] Another aspect of the present invention is a humidifier or a method for assembling a humidifier core, the method comprising creating a plurality of unit cells and stacking the plurality of unit cells together to form a laminate. Creating a unit cell may involve attaching a first membrane sheet to a first main surface of a separator having an outer frame and first and second frames, the outer frame being penetrated by openings extending from the outer edges of the first and second frames into a flow field region surrounded by the outer frame, and first and second ridges, each extending across the ends of the first and second frames, and attaching a second membrane sheet to a second main surface of the outer frame opposite the first main surface. The unit cells may be stacked such that, in the laminate of unit cells, the first and second ridges are spaced apart from each other by contacting the separators of adjacent unit cells, providing lateral passages extending through the laminate of unit cells. In some embodiments, attaching the first membrane sheet to the first main surface of the separator involves aligning the first membrane sheet with the edge of the first ridge. In some embodiments, attaching the second membrane sheet to the second main surface of the separator involves aligning the second membrane sheet with the edge of the second ridge.

[0039] In some embodiments, the separator has third and fourth ridges that extend from the first and second frame ends, respectively, and that are located on the opposing main surfaces of the outer frame, respectively, and stacking multiple unit cells involves aligning the unit cells in the stack by the abutments of the third ridge of one unit cell in the stack using the first ridge of adjacent unit cells in the stack.

[0040] Another aspect of the present invention provides a separator for use in a humidifier. The separator comprises an outer frame, and first and second frames, the outer frame being penetrated by openings extending from the outer edges of the first and second frames into a flow field region surrounded by the outer frame, and first and second ridges, each extending across the ends of the first and second frames.

[0041] In some embodiments, the separator has a plurality of flow field elements extending across a cavity between a first frame end and a second frame end. The flow field elements are spaced apart to define a passage extending across the cavity. In some embodiments, the opposing faces of the flow field elements are coplanar with the first and second main faces of the separator. In some embodiments, adjacent flow field elements are spaced apart from each other by a distance ranging from 1 mm to 5 mm. In some embodiments, the separator has a plurality of lateral supports extending between adjacent flow field elements and dimensioned so as not to obstruct the passage. In some embodiments, the opening is formed to have a drafted wall.

[0042] In some embodiments, the cavity has a width-to-length aspect ratio ranging from 1:1.2 to 1.2:1.

[0043] Other embodiments of the present invention provide a humidifier having a stack of unit cells, or a humidifier core. Each unit cell may have an outer frame, and separators having first and second main surfaces, a first membrane sheet joined to the outer frame by the first main surface of the separator, and a second membrane sheet joined to the outer frame by the second main surface of the separator. The outer frame and the first and second membrane sheets may define cavities within the outer frame. Opposing frame ends of the outer frame may be open so that a first flow can flow through the cavities in a first direction. The separators may have first and second ridges extending across the first and second frame ends. In the stack of unit cells, the first and second ridges may be spaced apart from each other by contacting the separators of adjacent unit cells, providing passages that extend through the stack of unit cells in a second direction intersecting the first direction. In some embodiments, the unit cells can all be stacked in the same orientation.

[0044] Further aspects and exemplary embodiments are shown in the accompanying drawings and / or described in the following description.

[0045] It should be emphasized that the present invention relates to all combinations and subcombinations of the above features, even if these are described in different claims. [Brief explanation of the drawing]

[0046] The attached drawings illustrate non-limiting exemplary embodiments of the present invention.

[0047] Figure 1 is a perspective view of a humidifier core according to an exemplary embodiment.

[0048] Figure 1A is an exploded perspective view of a humidifier core unit cell according to an exemplary embodiment.

[0049] Figure 1B is a magnified view of a portion of the humidifier core shown in Figure 1.

[0050] Figure 2 is a perspective view of an exemplary separator.

[0051] Figure 2A is a magnified view of one end of the separator in Figure 2.

[0052] Figure 2B is an enlarged perspective view showing half of the separator in Figure 2.

[0053] Figure 3 is a partial cross-sectional view showing an example of a unit cell.

[0054] Figure 3C is a partial cross-sectional view of an exemplary separator.

[0055] Figure 4 is a side view of an exemplary humidifier core.

[0056] Figure 5 is a partial side view of the humidifier core.

[0057] Figure 6 is a flowchart illustrating an exemplary method for assembling a humidifier core.

[0058] Figure 7 is a side elevation view of two stacked separators having different structures.

[0059] Figure 8 is a partial side view of the humidifier core, in which the ribs are arranged along the ends of the separator.

[0060] Figure 9 is a perspective view of an exemplary separator having a width different from its length.

[0061] Figure 10 is a perspective view of an exemplary counterflow separator having port openings for forming a manifold for gas flow.

[0062] Figure 10A is a perspective view of the separator in Figure 10, with the hidden lines visible.

[0063] Figure 11 is an exploded perspective view of an exemplary humidifier system having a housing that receives a humidifier core. Detailed description

[0064] In the following description, specific details are revealed to provide a more complete understanding of the invention. However, the invention may be carried out without these features. In other examples, well-known elements are not illustrated and described in order to avoid unnecessarily obscuring the invention. Accordingly, this specification and the drawings should be considered illustrative and not restrictive. In the drawings, the same reference numerals are used to indicate similar or identical components, parts, or features in different views of the embodiments and in different illustrated embodiments.

[0065] This technology provides a membrane gas exchange system. The following description describes the structure and method for manufacturing a fuel cell humidifier according to this technology. Those skilled in the art will understand that this technology, like other membrane gas exchange systems, can be applied to humidifiers for other purposes.

[0066] In a fuel cell humidifier implementing this technology, a water vapor permeable membrane separates a first (drier) flow, or the flow of fluid supplied to the fuel cell, from a second (more humid) flow, or the humid (i.e., water vapor-containing) flow. The first flow may be, for example, the supply of an oxidizer (e.g., air) to the fuel cell. The second flow may be, for example, the exhaust flow from the fuel cell. Because the second flow is more humid than the first flow, there is net water transport from the second flow to the first flow through the water vapor permeable membrane of the humidifier.

[0067] In a typical fuel cell application, the first flow is at a higher pressure than the second flow. For example, the first flow may be pressurized by a blower or compressor, and the second flow may be generated downstream from the fuel cell at a lower static pressure.

[0068] It is advantageous for water vapor permeable membranes to be of a type that is "selective" with respect to water vapor (meaning that they have much lower permeability to other species such as oxygen and nitrogen than to water vapor). Some embodiments of the present invention have membranes that are substantially impermeable to air but highly permeable to water vapor. In some embodiments, the membrane has a permeability to water vapor of at least 10,000 gas permeance units (GPUs).

[0069] In some embodiments, the membrane has selectivity for water vapor to air (excluding water vapor) of at least 100. In some embodiments, the membrane has selectivity for water vapor to nitrogen of at least 100.

[0070] When used in the humidifier described herein, the membrane preferably has sufficient mechanical strength to resist deflection at a differential pressure of at least 100 kPa between the first and second flows at a temperature of at least 110°C.

[0071] The film is preferably resistant to oxidation and hydrolysis at high temperatures and high pressures. The film may also be resistant to acidic water, sulfuric acid, and hydrofluoric acid. The film is preferably resistant to one or more, or all, of the following: drying, humidity cycles, heat cycles, freeze-thaw cycles, and pressure cycles.

[0072] Figure 1 shows a humidifier core 10 (sometimes also referred to as a humidifier cartridge) according to an embodiment. The fuel cell humidifier may have a housing (see, for example, housing 60 in Figure 11) that receives the humidifier core 10, guides the first and second flows into corresponding passages of the humidifier core 10, and collects the first and second flows after they have passed through the humidifier core 10. Apart from the moisture exchange that occurs through the membrane of the humidifier core 10, the humidifier maintains the separation of the first and second flows.

[0073] The humidifier core 10 has a laminate of flow field separators, such as the separator 20 shown in Figure 2. Membrane sheets 22-1 and 22-2 (generally and collectively, membrane sheet 22) of water vapor permeable membrane material are arranged on the first surface 24-1 (e.g., top surface) and the second surface 24-2 (e.g., bottom surface, not shown in Figure 1) of each separator 20, as shown in Figure 1A. The humidifier core may have end plates 33 (see, for example, Figure 5) at opposing ends of the humidifier core 10. The end plates 33 may be shaped to abut the top separator 20 and the bottom separator 20 of the laminate. For example, the end plate 33 in Figure 5 has ridges 28C that abut adjacent separators 20.

[0074] The membrane sheet 22 of the humidifier core 10 may be of an asymmetrical membrane material type. For example, one surface of the membrane material may be designed to be in contact with a first (drier) flow, and a second opposing surface of the membrane material may be designed to be in contact with a second (weaker) flow. For example, the membrane material may have a substrate having a permeable coating layer on one of its surfaces. The membrane sheet 22 of such a membrane material may be oriented so that the coating layer interfaces with a dry or high-pressure flow and faces away from a higher-humidity, typically lower-pressure, flow.

[0075] The humidifier core 10 may have a membrane sheet 22 made of a membrane material having one of various structures. In some embodiments, the membrane sheet 22 has a multilayer membrane material. For example, the membrane material may have a support layer (such as a layer of nonwoven fiber polymer material), a microporous layer, and a water vapor selective air impermeable coating layer. If the membrane sheet 22 has a support layer, the separator may be bonded to the support layer of the membrane sheet 22.

[0076] Another exemplary configuration of the membrane material applicable to the membrane sheet 22 is having, or comprising, a microporous layer and a water vapor selective coating layer. If the membrane sheet 22 has a microporous layer, the separator may be adhered to the microporous layer of the membrane sheet 22.

[0077] The film material applicable to the film sheet 22 may have additional layers. For example, a surface treatment may be applied to a selected layer of the film material.

[0078] In some film materials, an additional microporous layer is optionally attached to the selective layer using a support layer on one or both sides of the film material, such that the selective layer is located between two microporous layers. In some film materials, the support layer is bonded between the two microporous layers, and the selective coating is applied to the surface of either microporous layer. In some embodiments, the surface of the selective layer of the film sheet 22 is bonded to a separator.

[0079] It is desirable that the humidifier provides the desired level of moisture exchange between the first and second flows without significantly restricting the flow. In particular, it is desirable that the humidifier does not cause a large pressure drop in the first (drier) flow.

[0080] The humidifier core 10 can be considered to consist of unit cells 30 (see, for example, Figure 1A). Each unit cell 30 has one separator 20 and corresponding membrane sheets 22-1, 22-2 attached to opposing surfaces of the separator 20 (see, for example, Figure 1A). Any suitable number of unit cells 30 can be stacked together to form a humidifier core, as described below. In some embodiments, the humidifier core 10 has about 50 to 200 unit cells 30.

[0081] The humidifier core 10 has a cross-flow structure. The humidifier core 10 provides passages arranged to transport a first flow F1 through the humidifier core in a first direction, and a second flow F2 through the humidifier core in a second direction intersecting the first direction, as indicated by the arrows in Figure 1. In the embodiment shown in Figure 1, the second direction is substantially perpendicular to the first direction.

[0082] This technology is not limited to counter-flow configurations. An example of a counter-flow humidifier that embodies this technology will be described below in relation to Figures 11 and 11A.

[0083] The second flow F22 enters the humidifier core 10 through the inlet opening 25A (shown in Figure 1B, and discussed in further detail with reference to Figures 2 and 2A). The first flow F1 passes through the passage 32 between the unit cells.

[0084] Figure 2 shows an exemplary separator 20. Figure 2A is an enlarged view of one end of the separator 20, and Figure 2B is an enlarged perspective view showing half of the separator 20. In some embodiments, the separator 20 is a single structure formed from a suitable plastic or a material such as metal. For example, the separator 20 may be formed from polyphenylene sulfide (PPS) plastic. PPS is an example of a material having desirable properties with respect to the separator 20.

[0085] By using the same material or a material from the same polymer family to create the parts of the separator 20 and the membrane sheet that are bonded to each other, the bonding between the membrane sheet 22 and the separator 20 can be facilitated. For example, when the separator 20 is bonded to the microporous layer or support layer of the membrane sheet 22, the separator 20, the microporous layer, or the support layer may be formed from polymers of the same polymer family (e.g., both from PPS plastic, or both from PET plastic, or both from PP plastic, etc.).

[0086] In a structure where the portions of the membrane sheets 22-1 and 22-2 that are in contact with the support 20 are made from the same material as the support 20, a wide range of bonding processes can be applied to reliably bond the membrane to the support. In some embodiments, the support layer of the membrane sheet 22 (e.g., a nonwoven backing layer) is made using PPS.

[0087] PPS is an example of a good choice of material for the separator 20 and / or for the membrane sheet 22. Some of the advantages of PPS are that it is dimensionally stable at the temperature and humidity levels that the fuel cell humidifier will be exposed to during operation, it is chemically stable and does not tend to release chemicals that could damage or impair the operation of downstream fuel cells under the conditions expected in the humidifier, and it is a good and cost-effective way to mold PPS and mass-produce the separator 20.

[0088] The separator 20 can be manufactured, for example, by injection molding, additive manufacturing processes (e.g., 3D printing), or subtractive machining processes.

[0089] In some embodiments, the separator 20 has a molded portion of a first material that is overmolded with one or more second materials. For example, one or more overmolded materials can be provided to facilitate or optimize the bonding of the film sheets 22-1 and 22-2 to the separator 20. Overmolded materials or materials can be provided (for example, a material that is less expensive than PPS or has better properties than PPS in some way can be overmolded with PPS, or with ultrasonic welding or another material selected to facilitate another process of bonding the separator 20 to the film sheets 22-1 and 22-2. As another example, the overmolded material can be used to provide very thin areas (so that they can provide lateral support to the separator). Polypropylene (PP) is an example of a material that can be used to form very thin shapes or features.

[0090] In the example shown in Figure 2, the separator 20 has a frame 24 that is substantially square in plan view. In some embodiments, the frame 24 is rectangular (see, for example, Figure 9), or has another geometric shape such as a hexagon or trapezoid. The frame 24 has first and second frame ends 24A and 24B connected by first and second frame sides 24C and 24D. The frame 24 optionally has one or more longitudinal support portions 24E at one or more positions between the frame sides 24C and 24D and extending between the frame ends 24A and 24B.

[0091] The frame ends 24A and 24B each have an inlet opening 25A and an outlet opening 25B that pass through the frame ends 24A and 24B toward the internal region 26 of the frame 24, respectively. The openings 25A and 25B have drafted walls, which can reduce pressure loss in the flow passing through the openings 25A and 25B. The drafted walls in the openings 25A and 25B also facilitate the molding of the separator 20 (for example, by sliding and retracting a portion of the mold after the separator 20 has been molded).

[0092] The internal region 26 of the frame 24 has flow field elements 26A that help guide the fluid flow through the internal region 26 between the openings 25A and 25B. When membrane sheets (not shown in Figures 2 and 2A) are laminated on the upper surface 24-1 and the lower surface 24-2 of the separator 20, a plurality of parallel passages 27 are defined between the membrane sheets and a pair of adjacent flow field elements 26A, and between the membrane sheets, as well as the frame sides 24C and 24D, and their adjacent flow field elements 26A.

[0093] The flow field element 26A may have, for example, the shape of a rib extending between the frame ends 24A and 24B. The height or thickness of the flow field element 26A (in a direction perpendicular to the plane of the separator 20) may be greater than its width (in a direction perpendicular to its length and parallel to the plane of the separator 20). The width of the flow field element 26A can be reduced to increase or maximize the area for water vapor exchange between the first and second flows, and / or increase or maximize the cross-sectional area of ​​the passage 27 for a given footprint of the separator 20. The width of the flow field elements 26A can be optionally varied along their length, and / or the widths of the flow field elements and / or the spacing between them may differ from one another.

[0094] The thickness of the flow field element 26A is preferably substantially equal to the thickness of the frame sides 24C and 24D, so that the upper and lower surfaces of the frame sides 24C and 24D, as well as the upper and lower surfaces of the flow field element 26A on surfaces 24-1 and 24-2 of the separator 20, are substantially coplanar.

[0095] The spacing between adjacent flow field elements 26A can be selected to provide the membrane sheets 22-1 and 22-2 with a desired support angle, while increasing or maximizing the active areas of the membrane sheets 22-1 and 22-2 that can be used to provide water vapor exchange between the first and second flows. The spacing can be selected based, for example, on the mechanical properties of the membrane sheets 22-1 and 22-2 at temperatures within the expected operating temperature range, the maximum expected pressure difference across the membrane sheets 22-1 and 22-2, the expected change in the pressure difference during operation, the design life, and the level of pretension applied to the membrane sheets 22-1 and 22-2, if any. In some embodiments, adjacent flow field elements 26A are spaced apart from each other at a distance in the range of 1 to 5 mm (e.g., 2 to 3 mm in some embodiments).

[0096] The longitudinal support portion 24E has substantially the same thickness as the frame side portions 24C and 24D, and the flow field element 26A. The longitudinal support portion 24E is generally wider than the flow field element 26A, as shown in Figures 2 and 2A.

[0097] A lateral support portion 26B is provided to reinforce and strengthen the flow field element 26A in the lateral direction. The thickness of the lateral support portion 26B (in the direction perpendicular to the plane of the separator 20) is thinner than the thickness of the frame sides 24C and 24D and the flow field element 26A, so that the lateral support portion 26B does not block or improperly obstruct the passage 27. The lateral support portion 26B is preferably thin. The leading and trailing edges of the lateral support portion 26B can be optionally shaped (e.g., inclined) to facilitate smooth flow through the passage 27. It is preferable that the lateral support portion 26B is positioned so as not to contact adjacent membrane sheets 22-1 and 22-2, and the fluid can pass over or under them in the passage 27, for example, the lateral support portion 26B can be positioned on the central plane of the separator 20.

[0098] As shown in Figures 2A and 2B, the frame end 24A has a ridge 28A on the upper surface 24-1 of the separator 20 and a ridge 29A on the lower surface 24-2 of the separator 20. The frame end 24B has a ridge 29B on the upper surface 24-1 of the separator 20 and a ridge 28B on the lower surface 24-2 of the separator 20. The ridges 28A and 29A extend along the length of the frame end 24A, and the ridges 28B and 29B extend along the length of the frame end 24B.

[0099] Figures 3A and 3B are cross-sectional views of a portion of the unit cell 30. Figure 3A is a partial cross-section of the unit cell extending through the frame side portion 24C in a cross-section perpendicular to the plane. Figure 3B is a partial cross-sectional view of the unit cell extending through the frame end portion 24A in a cross-section perpendicular to the plane. Figure 3C is a partial cross-sectional view of the separator 20 extending through the frame side portion 24C in a direction perpendicular to the length of the frame side portion 24C, and through the lateral support portion 26B and the flow field element 26A in a direction perpendicular to the length of the flow field element 26A.

[0100] Figure 3A shows that the membrane sheets 22-1 and 22-2 are supported by the frame side 24C and the flow field element 26A. The membrane sheets 22-1 and 22-2 are also supported along their opposing edges by the frame side 24D (not shown in Figure 3A). The membrane sheets 22-1 and 22-2 may be attached to the separator 20. Attachment between the membrane sheets and the separator 20 may be provided by, for example, ultrasonic welding, laser welding, thermal bonding, adhesive bonding, insert molding, or other suitable attachment means.

[0101] In some embodiments, both membrane sheets 22-1 and 22-2 may be attached to the separator 20 along the periphery of the internal region 26 of the frame 24. In some embodiments, the attachment is substantially continuous. For example, the attachment line between the upper surface 24-1 of the separator 20 and the membrane sheet 22-1 may extend around the separator 20 along the upper surfaces of the frame sides 24C and 24D, and the frame ends 24A and 24B, and the attachment line between the membrane sheet 22-2 and the lower surface 24-2 of the separator 20 may extend around the separator 20 along the lower surfaces of the frame sides 24C and 24D, and the frame ends 24A and 24B. The attachment lines may be provided, for example, by adhesive, welding, or insert molding.

[0102] The membrane sheets 22-1 and 22-2 are sealed to the corresponding frame sides 24C and 24D, along their upper and lower surfaces, respectively. The sealing may be provided by mounting means.

[0103] As shown in Figure 3B, membrane sheets 22-1 and 22-2 partially overlap the frame end 24A. They similarly overlap the frame end 24B. Membrane sheets 22-1 and 22-2 are sealed to the upper and lower surfaces of the frame ends 24A and 24B, respectively, along the lengths of the frame ends 24A and 24B.

[0104] Figure 3A shows how the fluid flow passage 27 is defined between the flow field element 26A of the separator 20 and the membrane sheets 22-1 and 22-2. Figure 3C shows how the lateral support portion 26B extends across the width of the passage 27. The fluid can enter the passage 27 through the opening 25A passing through the frame end 24A (as shown in Figure 3B) and exit the passage 27 through the opening 25B.

[0105] As shown in Figures 2, 3B, and 5, the separator 20 has ridges 28A and 28B (collectively, ridge 28), and arbitrary ridges 29A and 29B (collectively, ridge 29). Ridges 28 and 29, individually or in combination, perform several functions, such as the following 11 or more. A. Maintain separation between the membranes of adjacent unit cells 30. B. To seal the fluid flow passage or chamber between adjacent unit cells 30. C. During the assembly of the unit cell 30, the positioning of the membrane sheets 22-1 and 22-2 on each surface of the separator 20 is guided. D. Facilitates the alignment of unit cells 30 when stacked to form the humidifier core.

[0106] In the illustrated embodiment, the ridge 28 functions as a spacer to maintain separation between adjacent separators 20 and to seal both sides of a passage 32 defined between adjacent unit cells 30.

[0107] In the illustrated embodiment, the ridge 29 facilitates the alignment of adjacent separators 20 during the assembly of the humidifier core 10 and, in combination with the ridge 28, functions as an alignment mechanism that facilitates the positioning of membrane sheets 22-1 and 22-2.

[0108] The functions provided by ridges 28 and 29 described above can be achieved with different arrangements of ridges 28 and 29. For example, Ridge 28 can function to maintain separation between adjacent unit cells 30 without the presence of any ridge 29. Ridges 28A and 28B may be on the same surface of separator 20, or on opposing surfaces of separator 20 (as shown in Figures 2 and 5). Ridge 29 may be interrupted or replaced by a series of columns or other alignment mechanisms.

[0109] In the embodiments shown in Figures 2, 2A, and 5, the frame end 24A has a ridge 28A on face 24-1 and a ridge 29A on face 24-2. In this embodiment, the ridges 28A and 29A extend along the length of the frame end 24A.

[0110] The separator 20 in Figures 2, 2A, and 5 also has a ridge 28B extending along the length of the frame end 24B on face 24-2, and a ridge 29B extending along the length of the frame end 24B on face 24-1.

[0111] Figure 4 is a partial side view of the humidifier core 10. For example, as shown in Figures 4 and 5, when stacking the unit cells 30 together, the surface 31 of the ridge 28A of the first unit cell 30 may abut against the separator 20 of the second unit cell 30 adjacent to the first unit cell 30, and the surface 31 of the ridge 28B of the second unit cell 30 may abut against the separator 20 of the first unit cell 30. This clearly defines the distance between the first unit cell 30 and the second unit cell 30, and defines the height of the passage 32 between the first unit cell 30 and the second unit cell 30.

[0112] As shown in Figure 5, the unit cell 30 may be placed between a pair of end plates 33. The end plates 33 may be molded to abut the top separator 20 and the bottom separator 20 within the laminate. In the example shown in Figure 5, the end plate 33 has a ridge 28C that abuts against the adjacent separator 20.

[0113] As shown in Figure 4, the ridges 28A and 29B (on the upper surface 24-1 of separator 20) are separated by a distance D1. The ridges 29A and 28B (on the lower surface 24-2 of separator 20) are separated by a distance D2. Membrane sheet 22-1 may be cut or resized and installed between the ridges 28A and 29B. Membrane sheet 22-2 may be cut or resized and installed between the ridges 29A and 28B. These features can help align the membrane sheets 22-1 and 22-2 to the separator 20 during the assembly of the single cell 30. If D1 and D2 are equal or approximately equal, membrane sheets 22-1 and 22-2 can advantageously have the same dimensions. In the example shown in Figure 4, membrane sheets 22-1 and 22-2 are offset from each other in the direction along the separator 20 by a distance equal to the width of ridges 29A and 29B.

[0114] In some embodiments, ridges 28A and 28B are of equal height (and have a height H1 as shown in FIG. 3B), and are higher than ridges 29B and 29A. Ridges 29B and 29A may have H2 (as shown in FIG. 3B), where H2 ≤ H1, and preferably H2 < H1. In some embodiments, one or both of ridges 29 are wider than ridge 28.

[0115] In the embodiments shown in FIGS. 1-5, when unit cells 30 are aligned in the laminate, one ridge 29 of one separator 20 contacts the ridge 28 of an adjacent separator 20. This contact, or engagement, helps to align unit cells 30 and form the humidifying device core 10.

[0116] In the exemplary humidifying device core 10 shown in FIGS. 4 and 5, the separator 20 is rotationally symmetric about a horizontal axis (in the middle plane of the separator) passing through the centers of frame side portions 24C and 24D for a 180-degree rotation. This allows unit cells 30 to be oriented in any direction, simplifying the assembly of the humidifying device. All separators 20 and single cells 30 of the humidifying device core 10 can be in the same orientation. This significantly simplifies assembly compared to designs that require similar components to be rotated relative to each other in several specific ways.

[0117] In FIGS. 4 and 5, it can be seen that a wide cross-passage 32 is defined between adjacent unit cells 30 of the humidifying device core 10. The cross-passage 32 extends across the humidifying device core 10 (from frame side portion 24C to frame side portion 24D). The fluid flow through the cross-passage 32 can exchange moisture with the fluid flow through the passages 27 of the unit cells 30 on both sides of each cross-passage 32. The membrane sheets 22-1 and 22-2 are supported by the separator 20 and can be made flat or substantially flat. The design of the single cell 30 does not require sharp bends in the membrane sheets 22-1 or 22-2. Sharp bends can create points of failure in the membrane.

[0118] Advantageously, the design of the humidifier core 10 allows for independent setting of the dimensions of passages 32 and 27. The height of passage 32 is determined by the height of the ridge 28. The dimensions of passage 27 are determined by the design of the separator 20. The flow geometry can be selected or optimized for each flow domain. For example, A. The relative lengths of aisles 27 and 32 can be adjusted by changing the aspect ratio (length-to-width ratio) of frame 24. B. The height of the passageway 32 can be adjusted by changing the height of the ridge 28. C. The height of the passageway 27 can be adjusted by changing the thickness of the frame 24.

[0119] The design of each flow domain may be selected or optimized for, for example, one or more of the following: • Height (i.e., the lowest or minimum height to increase or maximize the active region of the film at a given stack height), • To achieve a smoother or more uniform flow distribution, and, • To reduce or minimize pressure drop.

[0120] In many fuel cell humidifier applications, a large pressure difference exists between the drier flow of gas being humidified (receiving water) and the humidifier flow of gas supplying water. For example, it is common for the drier flow of gas to be at a higher pressure than the humidifier flow of gas. The pressure difference is typically in the range of 50 kPa to 100 kPa. In the humidifier core 10, the higher-pressure flow of gas can be directed through the cross passage 32, while the lower-pressure flow of gas can be directed through the passage 27. In this configuration, the pressure difference across the membrane sheets 22-1 and 22-2 presses them against the flow field element 26A and the longitudinal support section 24E, which provides mechanical support for the membrane sheets 22-1 and 22-2 on both sides of the separator 20.

[0121] The width of the passage 27 and the material of the membrane sheet 22 may be selected to allow the humidifier to operate at a desired pressure difference and temperature, while maintaining the deflection of the membrane sheet 22 below a threshold deflection.

[0122] As shown in Figure 5, the frame 24 of the first unit cell 30A is separated from the frame 24 of the adjacent second unit cell 30B by the ridges 28B of the first unit cell 30A and the ridges 28A of the second unit cell 30B, with the surface 31 of the ridge 28B of the first unit cell 30A in contact with the separator 20 of the first unit cell 30A. The direct contact between the separators 20 of the first and second unit cells provides a "hard stop" when the stack of unit cells 30 is assembled together. The height of the stack of unit cells 30 is determined by the dimension D3 of the separator 20. For example, the thickness of the membrane sheets 22-1 and 22-2, which may change due to membrane swelling, does not affect the height of the laminate of the unit cell 30.

[0123] Ridge 29, if present, may be lower in height than ridge 20 (as shown in Figure 3B, H2

[0124] ​The "hard stops" provided by the ridges 28 when the unit cells 30 are stacked help reduce or avoid seal failures between adjacent unit cells 30. This mitigates a failure mode that may plague humidifiers of a type where the height of the humidifier core is partially determined by the film. In humidifier cores where the height of the laminate is determined by the film thickness, variations in the height of the laminate can occur during humidifier operation due to the expansion and contraction of the film, which can lead to premature failure of the seals in the humidifier core. Other failure modes may be introduced, for example, by overcompressing the laminate to ensure effective interlayer sealing, which can puncture the film.

[0125] In the embodiment shown in Figure 1-5, the ridges 28 and 29 are all inserted into the frame ends 24A and 24B of the separator 20. Inserting the ridges 28 and 29 into the ends of the separator 20 is beneficial but not essential. When the unit cells 30 are stacked, a lateral groove 34 (see Figure 5) is formed between the separators 20 of adjacent unit cells 30. The groove 34 may receive a suitable material 35, such as an adhesive or sealant, to hold the stack of unit cells 30. Preferably, the material 35 is selected to be robust in terms of viscosity and sufficient operating conditions to prevent flow into the openings 25A and 25B during the assembly of the humidifier core. In some embodiments, the material 35 may be a curable sealant and may be UV curable. A favorable material 35 does not affect the height of the stack of unit cells 30.

[0126] In some embodiments, additional structures are provided to hold the unit cells 30 together in the humidifier core 10. The additional structures may be provided, for example, by wires, bands, or straps extending around the humidifier core 10, a frame, or cage that receives and holds together the unit cells 30 of the humidifier core 10, and the end plates 33.

[0127] In exemplary embodiments, the humidifier core 10 has a laminate of unit cells 30 housed within a stainless steel frame. The frame may have, for example, a pair of end plates connected by four corner posts. Different parts of the frame may be welded, joined, or attached by deformable elements such as bendable or twistable tabs. The frame can align and hold the unit cells 30 and maintain compression in the laminate of unit cells 30. In some embodiments, the humidifier core 10 may be mounted to the housing in a removable manner, as a result the laminate can be attached to and detached from the housing in a manner similar to that of attaching or detaching an air filter or cartridge.

[0128] The humidifier core 10 may be housed in a housing 60 (see, for example, Figure 11). In the illustrated embodiment, the housing 60 has a base 61A, a hollow body 61B sized to receive the humidifier core 10, and a cap 61C. Bolts 62 and other fasteners attach the cap 61C and the base 61A and house the humidifier core 10. An edge seal 61D of the body 61B seals the corners of the humidifier core 10. Fluid ports 63A and 63B each carry a first flow of gas, which flows into and out of the housing 60 through a passage 27 (not shown in Figure 11) of the humidifier core 10. Ports 64A and 64B each carry a second flow of gas, which flows into and out of the housing 60 through a passage 32 (not shown) of the humidifier core 10.

[0129] The opposing surfaces of the humidifier core 10, including the open end of the flow path 32 (formed by the stacked frame sides 24C and 24D), may be at least substantially flat to facilitate sealing between the humidifier core 10 and the conduits arranged to transport fluid to and from the humidifier core 10. To facilitate such sealing, the ends of all ridges 28 and 29 (if present) may be flat and coplanar with the outer edges of the frame sides 24C and 24D.

[0130] The height of the groove 34 may be made different from the height of the passage 32 by making the portions of the frame ends 24A and 24B outside the ridge 28 different in thickness from the frame sides 24C and 24D, and different in thickness from the portions of the frame ends 24A and 24B inside the ridges 28 and 29, respectively. In the embodiments shown in Figures 1-5, the portions of the frame ends 24A outside the ridges 28A and 29A, and the portions of the frame ends 24B outside the ridges 28B and 29B, are thicker than the portions of the frame ends 24A and 24B inside the ridges 28 and 29, so that the groove 34 has a height less than the height of the passage 32. The extra thickness of these portions of the frame ends 24A and 24B facilitates the design of the openings 25A and 25B, as described in other parts of this specification.

[0131] Advantageously, in some embodiments, the ridges 28 and 29 restrain the membrane sheets 22-1 and 22-2 and also function as a barrier between the membrane sheets 22-1 and 22-1 and the surfaces of the humidifying core 10 having the openings 25A and 25B. This configuration can mitigate a potential failure mode associated with the expansion of the membrane sheets 22-1 and 22-2 as a result of the opening 25A into which the gas enters being exposed to high humidity.

[0132] Figure 6 is a flowchart illustrating an exemplary method 50 for assembling the humidifier core. In block 52A, the membrane sheet 22-1 is positioned correctly on the surface 24-1 of the separator 20. Block 52A may also include mounting a pre-cut membrane sheet 22-1 between the ridges 28A and 29B of the separator 20.

[0133] In block 52B, the membrane sheet 22-1 is bonded to the separator 20. Block 52B may, for example, bond the membrane sheet 22-1 to the separator 20 and form a continuous seal around the membrane sheet 22-1.

[0134] In block 53A, the membrane sheet 22-2 is positioned in the correct location on the surface 24-2 of the separator 20. Block 53A may also include attaching the pre-cut membrane sheet 22-2 between the ridges 29A and 28B of the separator 20.

[0135] In block 53B, the membrane sheet 22-2 is bonded to the separator 20. Block 53B may also, for example, bond the membrane sheet 22-2 to the separator 20 and form a continuous seal around the membrane sheet 22-2.

[0136] Blocks 52B and 53B may have, for example, ultrasonic welding, laser welding, thermal bonding, adhesive bonding, etc., for attaching their respective films to the separator 20.

[0137] Blocks 52A and 52B may be executed relative to blocks 53A and 53B in any order or simultaneously. Once both blocks 52B and 53B are completed, a unit cell 30 is generated. In any block 54, the unit cell 30 is tested (for example, to ensure that the chamber formed by the membrane sheet and separator in each unit cell 30 is airtight).

[0138] In block 55, multiple unit cells 30 are assembled to form a humidifier core 10. In block 55A, a desired number of unit cells 30 are stacked together. Block 55A may have a mechanism for aligning the unit cells 30 by engaging the ridges of adjacent unit cells 30 in a contact relationship (for example, the ridge 28A of one single cell 30 may be in contact with the ridge 29A of an adjacent unit cell 30). Advantageously, all stacked unit cells may be stacked in the same orientation. Block 55A may have an end plate 33 provided at the ends of opposing stacks.

[0139] In block 55B, material 35, which may be a curable adhesive sealant, is applied to the unit cell 30. Block 55B may be performed during or after block 55A. In an exemplary embodiment, the unit cells 30 are added sequentially to the laminate of unit cells. Before adding each single cell to the laminate, material 35 (e.g., adhesive sealant beads) is applied to the surface that will form the wall of the groove 34. When each unit cell is added to the laminate, the unit cell to be added can be separated from the previous unit cell by a precise distance through the engagement of the surface 31 of the ridge 28. The material 35 holds the laminated unit cells 30 together.

[0140] In block 55C, the completed laminate of unit cells may be clamped together until the material 35 hardens. Method 50 optionally includes adding frames, banding, wires, etc., to compress the laminate of unit cells and / or holding the unit cells together within the laminate.

[0141] From the above, it can be understood that this technology provides a range of humidifier designs that can operate to transfer moisture between flows at different pressures. Humidifiers can be assembled by stacking unit cells together, each having a separator 20 that can define a flow path for lower-pressure flows, and a water vapor transport (WVT) membrane bonded to both sides of the separator. Both direct-to-alternating-to-counterflow, counterflow, or co-flow configurations are possible.

[0142] In a preferred embodiment, the unit cells are identical and symmetrical. In such an embodiment, assembly is simplified because the unit cells can be added to the stack of unit cells on either side facing the stack. Higher pressure flows can flow through passages between adjacent unit cells.

[0143] The geometric arrangement of the flow can be selected or optimized for each flow.

[0144] The apparatus described herein can be modified in various ways. For example, different embodiments may have one or more of the features described in the following paragraphs.

[0145] In some embodiments, the flow field element 26A defines a flow field in which the passage 27 is not straight. For example, the passage 27 may be straight, wavy, angled, or other configurations within the internal region 26 of the separator 20.

[0146] In some embodiments of the humidifier described herein, the separators are symmetrical in a plane that intersects the midpoints of the frame sides 24C, 24D and is perpendicular to the plane of the separator 20. In some such embodiments, for example, ridges that maintain hard-stop separation between adjacent separators 20 may be provided on the same plane of the separators (rather than on opposing planes, as in the embodiments shown in Figures 1-5). For example, higher ridges 28A and 28B that provide hard stops when the separators 20 are stacked may both be on the same plane of the separators 20. Ridges 29A and 29B may be on opposing planes of the separators 20 and offset from ridges 28A and 28B, respectively. Figure 7 is a side view of two stacked separators 20A having this alternative structure. Each separator 20A has a membrane sheet (not shown in Figure 7) attached to its top and bottom surfaces to form a unit cell. The unit cells can be stacked to form a humidifier core. In this embodiment, the dimensions of the membrane sheet attached to the upper surface of the separator 20A may differ from the dimensions of the membrane sheet attached to the lower surface of the separator 20A.

[0147] In the embodiment shown in Figure 1-5, ridges 28A and 29A are fitted to the end 24A of the separator 20, and ridges 29A and 29B are fitted to the end 24B of the separator 20. As described above, having ridges 28 and 29 fitted to the end of the separator 20 is beneficial but not essential. Figure 8 shows a partial side view of the humidifier core. In this embodiment, ridges 28A and 28B are positioned flush with the frame ends 24A and 24B of each separator 20, providing hard-stop separation between adjacent unit cells. Ridge portions 29A and 29B, which facilitate alignment and positioning of adjacent unit cells, are fitted to each of the frame ends 24A and 24B, and to each of the ridges 28A and 28B, respectively.

[0148] Figure 9 is a perspective view of an example of a rectangular separator having a width different from its length. In other respects, the separator shown in Figure 9 is the same as the separator shown in Figure 2, and the same or similar components, parts, or features are indicated using the same reference numerals.

[0149] In some embodiments, the separator defines ports for distributing flow within and between unit cells of the humidifier core. Several such separators, when stacked, can provide a counterflow humidifier. For example, Figures 10 and 10A show a separator 20C that provides counterflow humidity exchange, having a flow field arranged similarly to the rectangular separator shown in Figure 9. As in other embodiments described herein, a membrane (not shown in Figure 10 or 10A) may be fixed to the separator 20C, covering the opposing surfaces of the flow field and forming unit cells.

[0150] The separator 20C has a peripheral ridge 28D that provides a hard stop when stacked adjacent to an adjacent separator 20C. The separator 20C may have an alignment mechanism on the surface facing the peripheral ridge 28D. The alignment mechanism can align two stacked separators 28D by engaging, for example, the inner and / or outer surfaces of the peripheral ridge 28D.

[0151] When several separators 20D (each having a membrane sheet on both sides) are stacked, a corresponding manifold is provided that aligns the port openings 41A, 41B, 42A, and 42B of the stacked separators and extends through the stack of separators.

[0152] Port openings 41A and 41B are aligned to form a manifold, carrying a first flow through the space between adjacent unit cells, each unit cell having a separator 20C sandwiched between a pair of membrane sheets. Port openings 41A and 41B are aligned to form a manifold, carrying a second flow through the flow field into the internal region 26 of the separator 20C. For example, the second flow is delivered to an aligned port opening 42A, flows into the internal region 26 via a header region 44A defined in the separator 20C, collects the flow, and can pass through the internal region 26 to a collection region 44B that delivers the flow to port 42B. The separation of the first and second flows can be maintained using a suitable seal or gasket.

[0153] Unless the context clearly requires otherwise, throughout the specification and claims, The words "to possess" and "to have" should be interpreted in a comprehensive sense, rather than in an exclusive or exhaustive sense; that is, they should mean "to include, but not to be limited to." "To be connected" or "to be joined," and its variations, mean a direct or indirect connection or joining between two or more elements; the joining or connection between elements can be physical, logical, or a combination thereof. The terms “in this specification,” “above,” “below,” and similar terms relating to importation, when used in the description of this specification, refer to this specification as a whole, and not to any particular part thereof. • "Or" in reference to a list of two or more items encompasses all of the following interpretations: any item in the list, all items in the list, and any combination of items in the list. The singular forms that take "a," "an," and "the" also include the meaning of any appropriate plural form.

[0154] Terms indicating direction, such as “vertical,” “horizontal,” “horizontal,” “up,” “down,” “forward,” “backward,” “inward,” “outward,” “right,” “left,” “front,” “back,” “top,” “bottom,” “lower,” “upward,” and so on, as used herein and in the appended claims (if any), depend on the specific orientation of the device described and illustrated. The subject matter described herein may assume various alternative directions. Therefore, these directional terms are not strictly defined and should not be interpreted narrowly.

[0155] Where components (e.g., membranes, sealants, adhesives, assemblies, devices, etc.) are referred to above, unless otherwise indicated, references to such components (including references to “means”) should be interpreted to include, as equivalents to, any components that perform the function of the described component, and to include components that are not structurally equivalent to the disclosed structures that perform the function in exemplary embodiments of the present invention.

[0156] Specific examples of systems, methods, and apparatus are described herein for illustrative purposes only. These are examples only. The techniques provided herein can be applied to systems other than the exemplary systems described above. Many changes, modifications, additions, omissions, and rearrangements are possible in embodiments of the present invention. The present invention includes variations of the described embodiments which will be obvious to those skilled in the art, and includes variations obtained by replacing features, elements, and / or functions with equivalent features, elements, and / or functions; mixing and integrating features, elements, and / or functions from different embodiments; combining features, elements, and / or functions from embodiments described herein with feature elements, and / or functions of other technologies; and / or excluding combinations of features, elements, and / or functions from embodiments described herein.

[0157] This specification describes various features, as present in “Several Embodiments.” Such features are not essential and may not be present in all embodiments. Embodiments of the present invention may have zero, any one, or any combination of two or more such features. This is limited only to the extent that one of such features is incompatible with others of the same type, to the extent that it would be impossible for a person skilled in the art to construct a practical embodiment combining such incompatible features. Therefore, “Several Embodiments” having feature A and “Several Embodiments” having feature B, even if described with respect to different figures and / or in different paragraphs or sentences, should be interpreted as an indication that the present invention also considers embodiments combining features A and B (unless the specification refers to others or that features A and B are fundamentally incompatible).

[0158] Accordingly, the claims attached below, and any claims introduced thereafter, are intended to be interpreted as including all possible changes, rearrangements, additions, omissions, and subcombinations that could be reasonably inferred. The claims should not be limited by the preferred embodiments described in the examples, but should be interpreted in the broadest way consistent with the description of the entire specification.

Claims

1. A humidifier, A stack of unit cells, Each of the aforementioned unit cells is, An outer frame, and a separator having a first and a second main surface, On the first main surface of the separator, a first membrane sheet is bonded to the outer peripheral frame, and On the second main surface of the separator, a second membrane sheet is joined to the outer peripheral frame. It has, The aforementioned outer frame, and the first and second membrane sheets, A cavity is defined inside the aforementioned outer frame, The opposing first and second frame ends of the outer peripheral frame are The opening is such that the first flow can flow through the cavity in the first direction, from the first frame end of the outer frame toward the second frame end. The aforementioned separator is, Having a first and a second ridge, The first ridge is Located on the first or second main surface of the separator, extending laterally in the second direction along the first frame end, The second ridge is, Located on the first or second main surface of the separator, extending laterally in the second direction along the second frame end, The second direction is, Intersecting in the first direction, In the laminate of the unit cells, the first and second ridges are It contacts the separators of adjacent unit cells, separates pairs of adjacent unit cells from each other, and provides a passage that extends in the second direction through the stack of unit cells between pairs of adjacent separators. humidifier.

2. In the humidifier according to claim 1, The first and second ridges are, Each of the above-mentioned first and second frame ends is positioned inward from the outer edge, humidifier.

3. In the humidifier according to claim 2, The portion between the first ridge of the first frame end and the outer edge of the first frame end is, The first gaps separate the unit cells from each other in the laminate, and the first gaps have an adhesive that bonds the adjacent unit cells together. humidifier.

4. In a humidifier according to claim 2 or claim 3, The portion between the second ridge of the second frame end and the outer edge of the second frame end is, The second gaps are spaced apart from each other in the laminate of the unit cells, and the second gaps have an adhesive that bonds the adjacent unit cells together. humidifier.

5. In any of the humidifiers according to claims 1 to 4, The first and second ridges are, On the first and second main surfaces of the separator, respectively, humidifier.

6. In the humidifier according to claim 5, The aforementioned separator is, The separator is symmetrical with respect to a 180-degree rotation about an axis extending in the second direction through the intermediate surface and center. humidifier.

7. In a humidifier according to claim 5 or claim 6, The aforementioned separator is, The separator has a third ridge at the first frame end of the second main surface, The outer edge of the third ridge is Aligned with the inner edge of the first ridge, humidifier.

8. In the humidifier according to claim 7, The third ridge is, Having a height measured from the side of the outer frame that is smaller than the height of the second ridge measured from the side of the outer frame, humidifier.

9. In any of the humidifiers according to claims 1 to 8, The first and second membrane sheets are, respectively, A porous substrate, and a water vapor permeable coating on one side of the porous substrate, The first and second membrane sheets are, The water vapor permeable coating is positioned such that it faces away from the separator to which the first and second film sheets are attached. humidifier.

10. In any of the humidifiers according to claims 1 to 9, A plurality of flow field elements extending across the cavity between the first and second frame ends, It has, The aforementioned flow field element is They are spaced apart to define a passage that extends across the aforementioned cavity, humidifier.

11. In the humidifier according to claim 10, The adjacent flow field elements are spaced apart from each other by a distance of 1 to 5 mm. humidifier.

12. In a humidifier according to claim 10 or claim 11, Each of the aforementioned separators is The flow field elements have a plurality of lateral support portions that extend between adjacent ones and are sized so as not to obstruct the passage. humidifier.

13. In any of the humidifiers according to claims 10 to 12, The first and second frame ends are, Each is formed to extend through the first and second frame ends and to provide a plurality of openings that open to the corresponding passages, humidifier.

14. In any of the humidifiers according to claims 1 to 13, The aforementioned cavity is Having a width:length aspect ratio in the range of 1:1.2 to 1.2:1, humidifier.

15. In any of the humidifiers according to claims 1 to 14, A frame surrounding the stack of the aforementioned unit cells, It has, The aforementioned frame is A compressive force is applied to the stack of unit cells in a third direction that intersects the first and second directions. humidifier.

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