Fuel cell dry end with o-ring compression seal

Abstract

A fuel cell system, such as a motor vehicle, includes a fuel cell stack having fuel cells and non-repeating hardware components including a wet end unit and a dry end unit. A plurality of batteries are located between the end units. The dry end unit includes an end plate and a compression plate assembly that uniformly presses the battery against the end plate, and a terminal plate surrounded by a sealing plate. An insulator frame is disposed adjacent a compression plate assembly engaged with the insulator frame via a friction interface provided by an O-ring compression seal having respective posts connected to the terminal plate and the seal plate and a cavity connected to the insulator frame. The post and the cavity of the at least one compression seal together define a fluid passage. One or more pads may be disposed between the end plates and the insulator frame.

Description

Technical Field

[0001] The present disclosure relates to electrochemical fuel cell systems operable to convert gaseous hydrogen or another suitable reactant into electricity. More specifically, aspects of the present disclosure relate to hardware solutions for internal sealing and insulation of fuel cell systems. Background Art

[0002] Advanced hybrid electric and all-electric vehicles may employ fuel cell systems to generate electrical current. A hydrogen (H2) fuel cell is a specialized electrochemical device consisting of a negative electrode / anode that receives a supply of gaseous H2, a positive electrode / cathode that receives ambient air as an oxidant, and an electrolyte material between the anode and cathode. The induced electrochemical reaction oxidizes the H2 molecules on the anode side of the fuel cell. The hydrogen gas entering the fuel cell is catalytically split, producing free electrons and protons. The free protons travel through the electrolyte to the cathode side of the fuel cell, where they react with oxygen (O2) molecules from the surrounding environment. Water vapor and heat form inert byproducts of this chemical reaction. The free electrons from the anode are then directed to a connected load, such as one or more electric traction motors or other electrical components / accessories.

[0003] Fuel cell stacks for automotive and other high current applications often employ solid polymer electrolyte membranes (PEMs). The PEM provides the above-mentioned ion transport between the anode and cathode. The catalyst layers of the anode and cathode and the electrolyte membrane together define a membrane electrode assembly (MEA), which in turn is disposed between gas diffusion layers (GDLs). The GDLs are in turn disposed between bipolar plates (BPPs) to form a fuel cell. Multiple fuel cells are assembled into a fuel cell stack to produce the current and voltage required to power a given application. The BPPs together define a circuitous flow channel for distributing the H2 and O2 reactant gases through the fuel cell stack. Elastomeric seals or other types of seals, such as metal bead seals, are disposed around the edges of the MEA, the surfaces of the BPPs, and the end plate units of the stack to ensure effective separation of reactant and coolant flows while also preventing leakage and mixing of the various gases. Summary of the invention

[0004] A fuel cell system having a fuel cell stack is disclosed. The fuel cell stack includes non-repeating hardware (NRHW) components, one of which is configured as a dry end unit disposed opposite to a wet end unit. The solution proposed in this article is intended to make the dry end unit more compact and robust relative to existing structures.

[0005] A fuel cell system according to a representative embodiment includes a fuel cell stack having a plurality of fuel cells and the above-mentioned wet end unit and dry end unit. The fuel cell stack is positioned between the wet end unit and the dry end unit. The dry end unit may include a compression plate assembly, an insulator frame, and a plurality of O-ring compression seals. The compression plate assembly configured to uniformly compress the fuel cell includes a terminal plate (also referred to as a collector plate) and a sealing plate. Due to its typical 304 stainless steel (SUS) material structure, the sealing plate is sometimes informally referred to as a SUS plate. The terminal plate is surrounded by a sealing plate. The insulator frame is arranged adjacent to the compression plate assembly. The compression plate assembly and the insulator frame engage with each other via a friction interface provided by an O-ring compression seal. The friction interface based on O-rings contemplated herein is helpful in many ways, for example, when the dry end unit is handled as an assembled single unit during transportation, fuel cell stack assembly, and discharge of reactants and byproducts.

[0006] The O-ring compression seals may each include (i) an elongated post connected to or integrally formed with a sealing plate, (ii) an elongated post connected to or integrally formed with a terminal plate, and (iii) a recessed cavity defined by an insulator frame configured to receive the elongated post of the terminal plate or the elongated post of the sealing plate therein. In one or more embodiments, the elongated post connected to or integrally formed with the terminal plate or the sealing plate and the recessed cavity of at least one O-ring compression seal define a fluid passage.

[0007] At least one gasket may be disposed adjacent to the insulator frame. In such an embodiment, the at least one gasket may include a plurality of gaskets of different thicknesses. The gaskets collectively provide a predetermined level of cell compression of the fuel cells within the fuel cell stack. The gaskets may define one or more gasket openings.

[0008] Conductive bus bars may be connected to the terminal plates and protrude from the fuel cell stack.

[0009] In one or more embodiments, a direct current to direct current (DC-DC) converter is connected to the fuel cell stack, a direct current to alternating current (DC-AC) inverter circuit is connected to the DC-DC converter, and an AC power supply is connected to the DC-AC inverter circuit.

[0010] The present invention also discloses a dry end unit for a fuel cell stack. The dry end unit may include an end plate, a compression plate assembly, an insulator frame, and a plurality of O-ring compression seals. The compression plate assembly is configured to uniformly press a plurality of fuel cells of the fuel cell stack against the end plate, the compression plate assembly including a terminal plate surrounded by a sealing plate. The insulator frame is disposed adjacent to the compression plate assembly. The O-ring compression seal is configured to provide a friction interface between the compression plate assembly and the insulator frame, so that the compression plate assembly and the insulator frame engage with each other via the friction interface.

[0011] The present invention also discloses a motor vehicle having a fuel cell stack, a reactant supply tank in fluid communication with the fuel cell stack, a DC-DC converter connected to the fuel cell stack, a DC-AC inverter circuit connected to the DC-DC converter, and an AC traction motor connected to the DC-AC inverter circuit. In addition, one or more road wheels are connected to and powered by the AC traction motor.

[0012] A fuel cell stack in one or more embodiments of a motor vehicle includes a dry end unit having an end plate and a compression plate assembly, the compression plate assembly being configured to uniformly press a plurality of fuel cells of the fuel cell stack against the end plate, the compression plate assembly having a terminal plate surrounded by a sealing plate. A conductive bus bar is connected to the terminal plate and protrudes from the fuel cell stack. An insulator frame is disposed adjacent to the compression plate assembly. The compression plate assembly and the insulator frame engage with each other via a friction interface provided by a plurality of O-ring compression seals.

[0013] The present invention provides the following technical solutions:

[0014] 1. A fuel cell system, comprising:

[0015] a fuel cell stack having a plurality of fuel cells; and

[0016] A non-repetitive hardware (NRHW) component comprising a wet end unit and a dry end unit, wherein the fuel cell is located between the wet end unit and the dry end unit, the dry end unit comprising:

[0017] End plate;

[0018] a compression plate assembly configured to uniformly compress the fuel cell against the end plate and having a terminal plate surrounded by a sealing plate;

[0019] an insulator frame disposed adjacent the compression plate assembly; and

[0020] A plurality of O-ring compression seals are configured to provide a friction interface between the compression plate assembly and the insulator frame such that the compression plate assembly and the insulator frame engage one another via the friction interface.

[0021] 2. A fuel cell system according to Option 1, wherein the O-ring compression seals each include (i) an elongated column connected to the sealing plate or formed integrally with the sealing plate, (ii) an elongated column connected to the terminal plate or formed integrally with the terminal plate, and (iii) a recessed cavity defined by an insulator frame and configured to accommodate the elongated column of the terminal plate or the elongated column of the sealing plate therein.

[0022] 3. A fuel cell system according to Option 2, wherein at least one of the O-ring compression seals is connected to the terminal plate or formed integrally with the terminal plate by a slender column or connected to the sealing plate or formed integrally with the sealing plate and a recessed cavity to define a fluid channel.

[0023] 4. The fuel cell system according to claim 1, further comprising:

[0024] At least one backing plate is disposed adjacent to the insulator frame.

[0025] 5. The fuel cell system of claim 4, wherein the at least one gasket comprises a plurality of gaskets of varying thicknesses that collectively provide a predetermined level of cell compression for the fuel cells within the fuel cell stack.

[0026] 6. The fuel cell system according to claim 1, further comprising:

[0027] Conductive bus bars connected to the terminal plates and protruding from the fuel cell stack.

[0028] 7. The fuel cell system according to claim 1, further comprising:

[0029] a direct current-to-direct current (DC-DC) converter connected to the fuel cell stack;

[0030] a direct current to alternating current (DC-AC) inverter circuit connected to the DC-DC converter; and

[0031] AC powered equipment connected to a DC-AC inverter circuit.

[0032] 8. A dry end unit for a fuel cell stack, comprising:

[0033] End plate;

[0034] a compression plate assembly configured to uniformly compress a plurality of fuel cells of the fuel cell stack against the end plate, the compression plate assembly having a terminal plate surrounded by a sealing plate;

[0035] an insulator frame disposed adjacent the compression plate assembly; and

[0036] A plurality of O-ring compression seals are configured to provide a friction interface between the compression plate assembly and the insulator frame such that the compression plate assembly and the insulator frame engage one another via the friction interface.

[0037] 9. The dry end unit of claim 8, wherein each of the O-ring compression seals comprises (i) an elongated post connected to or integrally formed with the sealing plate, ii) an elongated post connected to or integrally formed with the terminal plate,

[0038] and (ii) a cavity defined by the insulator frame, the cavity being configured to receive the elongated post of the terminal plate or the elongated post of the sealing plate therein.

[0039] 10. A dry end unit according to Option 9, wherein the slender column connected to the terminal plate or formed integrally with the terminal plate or the slender column connected to the sealing plate or formed integrally with the sealing plate and the recessed cavity of at least one of the O-ring compression seals define a fluid channel.

[0040] 11. The dry end unit according to aspect 9, wherein the elongated column connected to or formed integrally with the terminal plate or the elongated column connected to or formed integrally with the sealing plate is cylindrical.

[0041] 12. The dry end unit according to solution 8 further comprises:

[0042] At least one backing plate is disposed between the end plate and the insulator frame.

[0043] 13. The dry end unit of claim 12, wherein the at least one gasket comprises a plurality of gaskets of varying thicknesses that collectively provide a predetermined level of cell compression of the fuel cells within the fuel cell stack.

[0044] 14. The dry end unit of embodiment 12, wherein the at least one backing plate defines a backing plate opening therethrough.

[0045] 15. The dry end unit according to solution 8 further comprises:

[0046] Conductive bus bars connected to the terminal plates and protruding from the fuel cell stack.

[0047] 16. A motor vehicle comprising:

[0048] Fuel cell stack;

[0049] a reactant supply tank in fluid communication with the fuel cell stack;

[0050] a direct current-to-direct current (DC-DC) converter connected to the fuel cell stack;

[0051] a direct current to alternating current (DC-AC) inverter circuit connected to a DC-DC converter;

[0052] an AC traction motor connected to a DC-AC inverter circuit; and

[0053] One or more road wheels connected to and powered by an AC traction motor, wherein the fuel cell stack comprises:

[0054] a dry end unit having an end plate;

[0055] a compression plate assembly configured to uniformly compress a plurality of fuel cells of the fuel cell stack against the end plate, the compression plate assembly having a terminal plate surrounded by a sealing plate;

[0056] an electrically conductive bus bar connected to the terminal plate and protruding from the fuel cell stack;

[0057] an insulator frame disposed adjacent the compression plate assembly; and

[0058] A plurality of O-ring compression seals, wherein the compression plate assembly and the insulator frame engage one another via a friction interface provided by the O-ring compression seals.

[0059] 17. A motor vehicle according to Option 16, wherein each of the O-ring compression seals includes (i) a slender column connected to the sealing plate or formed integrally with the sealing plate, ii) an elongated column connected to the terminal plate or formed integrally with the terminal plate, and (iii) a recessed cavity defined by an insulator frame and configured to accommodate the elongated column of the terminal plate or the elongated column of the sealing plate, and wherein the elongated column and the recessed cavity of at least one of the O-ring compression seals define a fluid passage.

[0060] 18. The motor vehicle according to claim 16, further comprising:

[0061] At least one backing plate is disposed between the end plate and the insulator frame.

[0062] 19. The motor vehicle of claim 18, wherein the at least one gasket comprises a plurality of gaskets of varying thicknesses that collectively provide a predetermined level of cell compression of the fuel cells within the fuel cell stack.

[0063] 20. The motor vehicle of claim 18, wherein the at least one gasket defines a gasket opening therethrough.

[0064] The above-mentioned features and advantages of the present disclosure and other features and attendant advantages will become apparent from the following detailed description of exemplary examples and modes for carrying out the present disclosure when taken in conjunction with the accompanying drawings and the appended claims. In addition, the present disclosure expressly includes combinations and sub-combinations of elements and features presented above and below. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0066] Figure 1 A representative automotive vehicle equipped with a powertrain having a fuel cell system constructed using the O-ring sealing strategy described herein is shown.

[0067] Figure 2 A representative fuel cell stack is shown having non-repetitive hardware (NRHW) components in the form of a dry end unit constructed in accordance with the present disclosure.

[0068] Figure 3A and Figure 3B yes Figure 2 A plan view of the opposite side of the compression plate assembly of the dry end unit is shown.

[0069] Figure 4 is used for Figure 2 A plan view of a representative insulator frame for a dry end unit is shown.

[0070] Figure 5 It is available with Figure 2 A plan view of a pad for use with a dry end unit.

[0071] Figure 6 is with Figure 2 A cross-sectional view of an O-ring compression seal used with a dry end unit.

[0072] Figure 7 yes Figure 6 A cross-sectional view of an O-ring compression seal is shown in FIG. 1 for use in conjunction with an anode / cathode header exhaust port.

[0073] Figure 8 In a possible multi-pad embodiment Figure 2 Illustration of a representative stack-up of dry-end units.

[0074] The present disclosure may be modified or implemented in alternative forms, wherein representative embodiments are shown in the drawings and described in detail below. The inventive aspects of the present disclosure are not limited to the disclosed embodiments. Rather, the present disclosure is intended to cover alternatives that fall within the scope of the present disclosure as defined by the appended claims. DETAILED DESCRIPTION

[0075] Referring to the drawings, wherein like reference numerals correspond to similar parts throughout the several views, Figure 1 The motor vehicle 10 shown is equipped with a fuel cell system 12 constructed according to the present disclosure. The motor vehicle 10 includes a body 14 connected to a set of road wheels 16. As shown, the motor vehicle 10 can be configured as a passenger vehicle, such as a sport utility vehicle, a car, a truck, a motorcycle, etc. However, the fuel cell system 12 can also be incorporated into a variety of vehicles, such as ships, aircraft, rail vehicles, agricultural equipment, etc., non-vehicle mobile platforms, or fixed systems such as power plants, cranes, etc. Therefore, the number of road wheels 16 attached to the body 14 can vary with the configuration of the motor vehicle 10. Figure 1The motor vehicle 10 is therefore used hereinafter as a non-limiting exemplary host system for the fuel cell system 12 , without limiting the present teachings to such use.

[0076] Figure 1 The fuel cell system 12 includes a fuel cell stack 18 in which a number of fuel cells 20 suitable for the application are arranged. The fuel cells 20 are arranged between non-repetitive hardware (NRHW) components 15, including Figure 2 The dry end unit 30D shown in FIG. Figure 3A-Figure 8 is constructed as described below. In addition to other incidental benefits, using Figure 2 The dry end unit 30D adds Figure 1 and Figure 2 The NRHW components 15 together integrate the individual fuel cells 20 into the fuel cell stack 18, support and assist in its construction, facilitate the provision of various fluid passages to / from the fuel cell stack 18, and act as electrical and thermal insulating structures therein. The NRHW components 15 also facilitate compression and anode / cathode header exhaust of the fuel cell stack 18, while serving as position holders for additional fuel cells 20 as needed.

[0077] Figure 1 The fuel cell system 12 uses a fuel cell stack 18 to generate on-board electricity. As understood in the art, air and hydrogen (H2) or another suitable reactant gas 17R are supplied from a reactant supply tank 17. The reactant supply tank 17 is in fluid communication with the fuel cell stack 18, for example, through a series of valves, pressure regulators and accessories (not shown). A suitable coolant (arrow 19) is similarly circulated through the fuel cell stack 18 to regulate the temperature of the fuel cell stack 18. The fuel cell stack 18, for its part, is constructed of a suitable number of fuel cells 20 for the application to generate electricity, and water vapor and heat are inert byproducts of its operation.

[0078] use Figure 1 The electrified powertrain 11 of the fuel cell stack 18 may include a direct current to direct current (DC-DC) converter 22 to convert a DC input voltage (V1) from the fuel cell stack 18 into a DC output voltage (V2) suitable for the application. This action may be performed by a boost operation facilitated by high-speed switching of semiconductor power switches and transformers (not shown) residing within the DC-DC converter 22, such as insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs) or other FETs, or other switchable semiconductor-based components. The electrified powertrain 11 may include one or more alternating current (AC) traction motors (M E) 25, as shown as part of the driven load, in this case a traction motor coupled to one or more road wheels 16 via one or more or more axles 160.

[0079] In this particular configuration, a direct current-alternating current (DC-AC) inverter circuit 24 is disposed between the DC-DC converter 22 and the AC traction motor 25. The internal switching operation of the inverter circuit 24 ultimately converts the DC output voltage (V2) into an AC input voltage (VAC) suitable for energizing the phase winding 250 of the AC traction motor 25 or another AC power supply device, thereby causing the machine to rotate and the motor output torque (T O ) is transmitted to one or more road wheels 16. Figure 1 Other possible components of the electrified powertrain 11 may include an auxiliary power module 26, i.e., another DC-DC converter operable to reduce the DC output voltage (V2) to an auxiliary voltage (V3) (e.g., nominally approximately 12-15V). AUX )28 is fed with an auxiliary voltage (V3) to power low voltage functions on the motor vehicle 10, such as lights, display screens, door locks, windows, etc.

[0080] Brief reference Figure 2 , Figure 1 The fuel cell stack 18 is shown in simplified form. The NRHW component 15 includes respective wet end units 30W and dry end units 30D, between which a repeated number of the above-mentioned fuel cells 20 and the positive electrode E1 and the negative electrode E2 are arranged. The wet end unit 30W and the dry end unit 30D each include respective end plates 15P that form a reaction surface during cell compression. Each fuel cell 20 includes a pair of bipolar plates 38, with a membrane electrode assembly 36 disposed therebetween. One or more fluid inlets 32 disposed on the wet end unit 30W are configured to allow a suitable reactant gas, such as hydrogen ( Figure 1 ) enters the fuel cell stack 18. Thus, "wet" refers to a specific inlet / outlet surface of the fuel cell stack 18. One or more fluid outlets 34, also provided on the wet end unit 30W in this embodiment, can allow water vapor and heat to be discharged to the surrounding ambient environment. For simplicity, Figure 2 Other ports for supplying coolant and air are omitted from , but such ports may be used in alternative configurations of the fuel cell stack 18 within the scope of the present disclosure.

[0081] Figure 3A and Figure 3B Shown with Figure 2A representative compression plate assembly 40 for use with a dry end unit 30D is provided to uniformly compress the fuel cell 20 against the end plate 15P of the dry end unit 30D. As contemplated herein, the compression plate assembly 40 has a generally rectangular perimeter shape formed with a double plate construction. In this construction, a terminal plate 42, such as a copper flat bar or plate or other suitable electrical conductor (also referred to in the art as a current collector), is disposed within or surrounded by a sealing compression plate ("sealing plate" 44, such as a stainless steel plate, such as 304SUS as described above). The sealing plate 44 may define a through hole or window 45, and the terminal plate 42 is disposed within the window 45 and may be attached to the surrounding sealing plate 44 around its periphery, such as by welding or brazing. The conductive busbar 46 may be connected to the terminal plate 42 as shown, also by welding or brazing, wherein the conductive busbar 46 may be formed or connected to the terminal plate 42. Figure 2 In such an embodiment, the conductive busbar 46 serves as an electrode connector and protrudes from the fuel cell stack 18 by an appropriate distance.

[0082] As part of the present structure, the terminal plate 42 and the sealing plate 44 are connected to or integrally formed with a plurality of O-ring compression seals 50, such as Figure 3B As shown. The O-ring compression seal 50 is configured to provide a friction interface between the compression plate assembly 40 and the insulator frame 60, so that the compression plate assembly 40 and the insulator frame 60 engage with each other via the friction interface. As described above, this is helpful in many aspects, such as when the dry end unit 30D is handled as an assembled single unit during transportation, during assembly of the fuel cell stack 18, and during discharge of reactants and byproducts. In one possible configuration, the O-ring compression seal 50 includes an elongated post 52 that is connected at one end 520 to a corresponding surface 42S of the terminal plate 42 or a corresponding surface 44S of the sealing plate 44 at different locations. As described below, one or more elongated posts 52 surround and at least partially define a fluid channel 66 (see Figure 3A O-ring compression seals 50 together facilitate secure integration of compression plate assembly 40 into Figure 1 and 2 In particular, the O-ring compression seal 50 facilitates the integration of the compression plate assembly 40 with the insulator frame 60 of the fuel cell stack 20, as will now be described with reference to Figure 4 Described in detail.

[0083] Figure 4 The insulator frame 60 is constructed as a generally rectangular plate of a suitable thermal and electrical insulating material (e.g., a polymer dielectric). As contemplated herein, the insulator frame 60 includes an interface surface 62, Figure 1 and Figure 2In the assembled fuel cell stack 18, the interface surface 62 directly abuts the compression plate assembly 40 shown in Figures 3A and 3B. A plurality of recessed cavities 64 are defined by or integrally formed with the interface surface 62 of the insulator frame 60, each of which serves as a means for positioning and fixing the above-mentioned elongated posts 52 protruding from the terminal plate 42 and the sealing plate 44 (see Figure 3B ) of the mating joint. In some cases, the cavity 64 can define a fluid passage 66 through the insulator frame 60 and the sealing plate 44, wherein Figure 3A , Figure 3B and Figure 4 6 and are indicated by A and B. Thus, the recessed cavity 64 may be closed at one end so that fluid cannot flow through the insulator frame 60 and the sealing plate 44 at the connection point corresponding to the recessed cavity 64, or the recessed cavity 64 may be open at both ends to form the corresponding fluid passage 66 as a through passage.

[0084] The specific number and location of the elongated posts 52, which may be cylindrical / circular in cross-section in one or more embodiments, and the recessed cavities 64 may vary depending on the embodiment. Figure 1 and 2 The specific configuration of the fuel cell stack 18 varies. Figure 3A , Figure 3B and Figure 4 The embodiments of the compression plate assembly 40 are characterized by the absence of bolts, screws or other threaded fasteners in one or more embodiments, the function of which is instead performed by the O-ring compression seal 50 .

[0085] refer to Figure 5 , Figure 3A and Figure 3B The compression plate assembly 40 and Figure 4 The insulator frame 60 can be used in conjunction with one or more backing plates 70 to achieve mechanical precision. At least one backing plate 70 contemplated herein is disposed adjacent to the insulator frame 60 to serve as one or more gauge plates and to help control Figure 1 and 2 The gasket 70 may define one or more gasket openings 72, for example, in line with a header (not shown) of the fuel cell stack 18. Such gasket openings 72 may be used in one or more embodiments to reduce the weight of the gasket 70 without changing the load path, and may have a variety of shapes and locations on the surface 73 of the gasket 70, including but not limited to circular, rectangular, polygonal, etc. As described below with reference to Figure 8As described above, one or more gaskets 70 may be selected from a stock of gaskets 70 during manufacturing and used as needed within the fuel cell stack 18, wherein the gaskets 70 may have various thicknesses to optimize the use of the gaskets 70. Figure 1 and Figure 2 The configuration of the fuel cell stack 18 is shown in a representative embodiment of FIG.

[0086] Figure 6 and Figure 7 Depicted Figure 3A-Figure 4 The O-ring compression seal 50 along Figure 3B The cross-sectional views are respectively taken along the cutting lines 8-8 and 9-9. Figure 6 As shown, each concave cavity 64 of the insulator frame (IF) 60 serves as a joint for accommodating and fixing the above-mentioned slender column 52 therein, wherein the slender column 52 protrudes from the terminal plate (TP) 42 adjacent to the fuel cell stack (FCS) 18, as described above. The slender column 52 can also define a circumferential groove 55, for example, near the distal end 53 of the slender column 52 opposite the terminal plate 42. An elastomeric O-ring 56 is disposed in the circumferential groove 55, and the elastomeric O-ring 56 is composed of a material suitable for the application. The construction of the O-ring 56 depends on the operating conditions, such as the temperature range and the specific fluids encountered in the fuel cell stack 18, and non-limiting exemplary materials include fluoroelastomers, silicones, polytetrafluoroethylene (PTFE), and ethylene-propylene-diene monomer copolymers (EPDM) suitable for the application. Similarly, various elastomeric O-rings 56 can be composed of different materials at different locations in the fuel cell stack 18.

[0087] As described above, some of the elongated posts 52 may be cylindrical shells, i.e., hollow, thereby defining an axially extending inner diameter wall 58 therein. Such a configuration will provide for the provision of a seal suitable for contact with the fluid passage 66 (regions A and B) and a non-fluid conducting O-ring compression seal 50 (e.g., on the terminal plate 42, such as Figure 6 The invention also provides a common structure for use with EMBODIMENTS (as shown) to reduce the number of parts.

[0088] That is, Figure 7 As shown, the elongated posts 52 may be attached to or integrally formed with the sealing plate (SP) 44 and used to direct fluid (arrow CC) through the insulator frame 60. To facilitate connecting the insulator frame 60 to external hardware, such as the anode / cathode header exhaust port 69, a flange post 68 may extend from the insulator frame 60. The flange post 68, for its part, may be externally connected and attached to another O-ring 56 for optimal fluid sealing. That is, the exhaust port 69 may be pressed onto the flange post 68 as shown by the arrow DD, so that the elastomeric O-ring 56 forms a fluid seal between the exhaust port 69 and the flange post 68.

[0089] Figure 8 is a simplified diagram of a representative gasket stack 80 of the gasket 70 described above, wherein one gasket is Figure 5 . In possible configurations, multiple gaskets 70 may be obtained in a variety of thicknesses, such as from about 0.25 mm to about 5 mm. Multiple thicknesses provide a wider range of combinations to achieve precise cell compression adjustment. For example, there may be a slack area 75 within the fuel cell stack 18 between the NRHW component 15 and the insulator frame 60 of the dry end unit 30D, wherein the slack area 75 is an area not occupied by components of the fuel cell stack 18. Such a slack area 75 in one or more embodiments may be filled with a first gasket layer L1 of a relatively thick gasket 70 within this range, wherein two such gaskets 70 constitute two gasket layers L1-A and L1-B, each gasket layer being approximately 4-5 mm in a possible embodiment. A smaller second gasket layer L2 may be constructed with multiple thinner versions of the gasket 70, such as gasket layers L2-A, L2-B, L2-C, and L2-D in a representative four-layer embodiment of the second gasket layer L2. In a possible embodiment, each of the shim layers L2-A, L2-B, L2-C, and L2-D may be about 1-2 mm. If there is still space within the slack region 75, one or more of the thinnest available shims 70 (e.g., 0.25 mm-0.5 mm) may be inserted as layer L3 into the remaining space to provide a predetermined level of battery compression.

[0090] Therefore, the above-described fuel cell system 12 incorporates as part of its construction Figure 2 The dry end unit 30D is used as the NRHW component 15. As a part of the dry end unit 30D, a pair of metal plates, namely Figure 3A and Figure 3B The terminal plate 42 and the sealing plate 44 are used to uniformly compress Figure 2 The fuel cell 20 is provided to facilitate collection of electricity generated by the fuel cell stack 18 . Figure 3A-Figure 4 Various distribution of O-ring compression seals 50 help seal and integrate the compression plate assembly 40 and the insulator frame 60 ( Figure 4 ), such as Figure 6 and Figure 7 The insulator frame 60 provides application-specific levels of thermal and electrical insulation. The hardware solutions described herein also increase the overall rigidity of the fuel cell stack 18 and allow for the use of Figure 5 and Figure 8 The backing plate 70 is used for Figure 1 and Figure 2 Precise compression of the fuel cell stack 18. In view of the foregoing disclosure, those skilled in the art will readily appreciate these and other attendant benefits of the disclosed dry end unit 30D.

[0091] The present disclosure may take many different forms of embodiments. Representative examples of the present disclosure are shown in the accompanying drawings and described in detail herein as non-limiting examples of the disclosed principles. For this reason, elements and limitations described in the abstract, introduction, overview, and detailed description sections but not explicitly set forth in the claims should not be incorporated into the claims individually or collectively by implication, inference, or otherwise.

[0092] For the purposes of this detailed description, unless expressly denied, the use of the singular includes the plural and vice versa; the terms "and" and "or" are both conjunctions and disjunctions; and the words "include", "contain", "includes", "have", etc. all mean "including but not limited to". In addition, approximate words such as "about", "almost", "substantially", "substantially", "approximately", etc. may all be used herein in the sense of "at, close to, or nearly at..." or "within 0-5% of..." or "within acceptable manufacturing tolerances" or any logical combination thereof. As used herein, a component "configured to" perform a specified function is capable of performing the specified function without change, rather than merely having the potential to perform the specified function after further modification. In other words, when expressly configured to perform a specified function, the hardware described is specifically selected, created, implemented, utilized, programmed and / or designed for the purpose of performing the specified function.

Claims

1. A fuel cell system, comprising: a fuel cell stack having a plurality of fuel cells; and A non-repetitive hardware (NRHW) component comprising a wet end unit and a dry end unit, wherein the fuel cell is located between the wet end unit and the dry end unit, the dry end unit comprising: End plate; a compression plate assembly configured to uniformly compress the fuel cell against the end plate and having a terminal plate surrounded by a sealing plate; an insulator frame disposed adjacent the compression plate assembly; and A plurality of O-ring compression seals are configured to provide a friction interface between the compression plate assembly and the insulator frame such that the compression plate assembly and the insulator frame engage one another via the friction interface.

2. A fuel cell system according to claim 1, wherein the O-ring compression seals each include (i) a slender column connected to the sealing plate or formed integrally with the sealing plate, (ii) a slender column connected to the terminal plate or formed integrally with the terminal plate, and (iii) a recessed cavity defined by an insulator frame and configured to accommodate the slender column of the terminal plate or the slender column of the sealing plate therein.

3. The fuel cell system according to claim 2, wherein: An elongated post connected to or integrally formed with the terminal plate or an elongated post connected to or integrally formed with the sealing plate and a recessed cavity of at least one of the O-ring compression seals define a fluid passage.

4. The fuel cell system according to claim 1, further comprising: At least one backing plate is disposed adjacent to the insulator frame. 5 . The fuel cell system of claim 4 , wherein the at least one gasket plate comprises a plurality of gasket plates of varying thicknesses that collectively provide a predetermined level of cell compression of the fuel cells within the fuel cell stack.

6. The fuel cell system according to claim 1, further comprising: Conductive bus bars connected to the terminal plates and protruding from the fuel cell stack.

7. The fuel cell system according to claim 1, further comprising: a direct current-to-direct current (DC-DC) converter connected to the fuel cell stack; a direct current to alternating current (DC-AC) inverter circuit connected to a DC-DC converter; and AC powered equipment connected to a DC-AC inverter circuit.

8. A dry end unit for a fuel cell stack, comprising: End plate; a compression plate assembly configured to uniformly compress a plurality of fuel cells of the fuel cell stack against the end plate, the compression plate assembly having a terminal plate surrounded by a sealing plate; an insulator frame disposed adjacent the compression plate assembly; and A plurality of O-ring compression seals are configured to provide a friction interface between the compression plate assembly and the insulator frame such that the compression plate assembly and the insulator frame engage one another via the friction interface.

9. The dry end unit of claim 8, wherein each of the O-ring compression seals comprises (i) an elongated post connected to or integrally formed with the sealing plate, ii) an elongated post connected to or integrally formed with the terminal plate, and (ii) a cavity defined by the insulator frame, the cavity being configured to receive the elongated post of the terminal plate or the elongated post of the sealing plate therein.

10. The dry end unit of claim 9, wherein the elongated post connected to or integrally formed with the terminal plate or the elongated post connected to or integrally formed with the sealing plate and the recessed cavity of at least one of the O-ring compression seals define a fluid passage.

Images