Expandable and adaptable fuel cell systems

Abstract

The present teachings are related to fuel cell systems having a fuel cell housing that can be expanded, for example, with one or more battery modules, one or more inverter modules, a DC power management module, an external power management module and. / or a solar MPPT module on the front end of the fuel cell housing, and adaptable to various environmental conditions with the use of other auxiliary modules readily attachable to the back end of the fuel cell housing.

Description

[0001] EXPANDABLE AND ADAPTABLE FUEL CELL SYSTEMS

[0002] CROSS REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Application No. 63 / 697,171, filed on September 20, 2024, which is incorporated herein by reference in its entirety.

[0004] HELD

[0005] The present teachings are related to fuel cell systems having a fuel cell housing that is expandable and adaptable to operate in various environmental conditions.

[0006] BACKGROUND

[0007] As the world moves away from fossil fuels and towards renewable and clean or “green’- energy, hydrogen energy is an attractive solution to reducing the carbon footprint created by many energy sources. Hydrogen produced from water via electrolysis using a renewable energy source does not produce any greenhouse gases and can be a completely carbon-free process. Fuel cells, which use hydrogen to produce electricity and water, have the possibility to impact clean energy for the future.

[0008] Consequently, fuel cell systems continue to be the focus of considerable attention due to the potential of fuel cell systems or simply, “fuel cells,” i.e., devices for the electrochemical conversion of hydrogen to electricity, to play a greatly expanded role for general applications including main power units (MPUs) and auxiliary power units (APUs) for households and businesses. Fuel cells also can be used for specialized applications, for example, as on-board electrical generating devices for electric vehicles, backup power sources for residential-use devices, main power sources for leisure-use, outdoor and other power-consuming devices in out-of-grid locations, and lighter weight, higher power density, ambient temperature-independent replacements for portable battery packs.

[0009] To that end, fuel cell systems such as solid oxide fuel cell systems, which currently are used in residential applications, typically use natural gas (mainly methane) as a fuel source. The natural gas is reformed into hydrogen, which is used by a fuel cell stack to generate electricity. Such household fuel cell systems that run on natural gas are ideal “electrical” back-ups for residences when the electrical grid goes down because of a storm or other power outage event. Such fuel cell units are typically placed outside the home so are visible to the consumer and neighbors.

[0010] Accordingly, readily expandable and adaptable fuel cell systems are needed to account for the various needs of a consumer, whether a residential fuel cell system or a business facility fuel cell system. SUMMARY

[0011] When purchasing fuel cell system, a consumer might not have a need for a complete fuel cell system with additional batteries, inverters, a DC power management unit and / or a solar MPPT unit, along with other environmentally adaptable components that may be needed. After use of the fuel cell system, certain of these additions might be desired. Accordingly, a fuel cell system with a fuel cell housing that can readily be expanded to include one or more battery modules, one or more inverter modules, a DC power management module, an external power management module, and / or a solar MPPT module can be advantageous to consumers. To that end, having one or more battery modules, one or more inverter modules, a DC power management module, an external power management module, and / or a solar MPPT module that can be plugged into the front end of a fuel cell housing or to another exterior facing module already connected to the fuel cell housing would be a solution to this situation permitting ease of installation by the consumer. Further, if each of the modules and their housing has substantially the same cross-sectional size and shape as the fuel cell housing, the expanded fuel cell system would provide an aesthetically pleasing product.

[0012] Accordingly, the present teachings are related to fuel cell systems having a fuel cell housing that can be expanded upon, for example, with one or more battery modules, one or more inverter modules that may or may not include additional load management capability, a DC power management module, an external power management module and / or a solar MPPT module on the front end of the fuel cell housing such that the additional modules have substantially the same cross-sectional shape and size as the fuel cell housing so it looks the same and is appealing to the consumer. The fuel cell system also can include additional auxiliary modules that are added to the back end of the fuel cell housing also in a modular plug-in style. The additional auxiliary components can include a filter module, a heat exchanger module, a heat exchanger / filter module, and a fuel filter module.

[0013] In various embodiments, a fuel cell system of the present teachings comprises a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end. The front end of the fuel cell housing can comprise a front end fuel cell housing interface configured to receive a back end battery module interface of a battery module, a back end inverter module interface of a inverter module, a back end DC power management module interface of a DC power management module, a back end external power management module interface of an external power management module or a back end of a solar MPPT module interface of a solar MPPT module. Each of the battery module, the inverter module, the DC power management module, an external power management module and the solar MPPT module have substantially the predetermined cross-sectional shape and size as the fuel cell housing, and the back end battery module interface, the back end inverter module interface, the back end DC power management module interface, the back end external power management module interface or the back end solar MPPT module interface can plug into the front end fuel cell housing interface. In this construction, any one of the battery modules, the inverter module, the DC power management module, the external power management module or the solar MPPT module is plugged into the front end fuel cell housing interface expanding the capabilities of the fuel cell system.

[0014] In a similar fashion, a front end of an exterior-most module (e.g., one of a battery module, an inverter module, a DC power management module, an external power management module or a solar MPPT module) is configured to receive a back end battery module interface, a back end inverter module interface, a back end DC power management module interface, a back end external power management module or a back end of a solar MPPT module interface. In this construction, any one of a battery module, an inverter module, a DC power management module, an external power management module or a solar MPPT module is plugged into the front end of the exterior-most module. When a solar MPPT module is present, it should be the exterior-most module on the front of the fuel cell system.

[0015] In like fashion, a front end of a then exterior- most module (i.e., the last module added to the front of the fuel cell housing) is configured to receive the back end battery module interface(s), the back end inverter module interface(s), the back end DC power management module interface(s), the back end external power management module interface(s) or the back end of a solar MPPT module interface. The modules of the present teachings for the front end of a fuel cell system are interchangeable and can be placed in any order starting from the front end of the fuel cell housing. For example, a fuel cell system can include one or more of four battery modules, one or more of three inverter modules, one DC power management module, one external power management module and one solar MPPT module, in any order beginning from the fuel cell housing, provided that the one solar MPPT module, when present, is the exterior-most module on the front of the fuel cell system.

[0016] Further, the modules of the present teachings are designed to plug into one another. To accomplish this design, the electronics and communications bus(s) are aligned for each module where male and female connections are possible. Each of the different modules can plug into each other (back end into front end) through these bus(s) such that the fuel cell system controller can identify and operate the modules that are attached to the fuel cell system. In addition, to ease plugging one module into another module, each of the fuel cell housing, battery module(s), inverter module(s), the DC power management module, the external power management module and the solar MPPT module comprises a front end locating feature and a back end locating feature, where the front end locating feature of one module aligns with the back end locating feature of another module.

[0017] The foregoing as well as other features and advantages of the present teachings will be more fully understood from the following figures, description, examples, and claims.

[0018] DESCRIPTION OF THE DRAWINGS

[0019] It should be understood that the drawings described below are for illustration purposes only. Like numerals generally refer to like parts, although not necessarily to identical parts. The drawings are not necessarily to scale, with emphasis generally being placed upon illustrating the principles of the present teachings. The drawings are not intended to limit the scope of the present teachings in any way.

[0020] FIGS. 1 A-1B are perspective views of a fuel cell system of the present teachings without any additional modules. FIG. 1A is a front, side view of the fuel cell system. FIG. IB is a back, side of the fuel cell system.

[0021] FIGS. 2A and 2B are front, side perspective views of a fuel cell system of the present teachings showing a blank removeable cover face plate including two pieces, where FIG. 2B shows the removal of the lower portion of the blank removeable cover face plate.

[0022] FIGS. 3A-3C are perspective views of a fuel cell system of the present teachings showing the addition of a battery module to the fuel cell housing. FIG. 3A is an exploded front, side view of the front end fuel cell housing interface and the front end battery module interface. FIG. 3B is an exploded back, side view of the back end battery interface. FIG. 3C is a front, side view of the assembled fuel cell system including an additional battery module.

[0023] FIGS. 4A-4C are perspective views of a fuel cell system of the present teachings showing the addition of two battery modules to the fuel cell housing. FIG. 4A is an exploded front, side view of the front end fuel cell housing interface and the two front end battery module interfaces. FIG. 4B is an exploded back, side view of the two back end battery module interfaces. FIG. 4C is a front, side view of the assembled fuel cell system including two battery modules.

[0024] FIGS. 5A-5C are perspective views of a fuel cell system of the present teachings showing the addition of three battery modules to the fuel cell housing. FIG. 5A is an exploded front, side view of the front end fuel cell housing interface and the front end battery module interfaces. FIG. 5B is an exploded back, side view of the back end battery module interfaces. FIG. 5C is a front, side view of the assembled fuel cell system including three battery modules.

[0025] FIGS. 6A-6C are perspective views of a fuel cell system of the present teachings showing the addition of a battery module and an inverter module to the fuel cell housing. FIG. 6A is an exploded front, side view of the front end fuel cell housing interface, the front end battery module interface, and the front end inverter module interface. FIG. 6B is an exploded back, side view of the back end battery module interface and the back end inverter module interface. FIG. 6C is a front, side view of the assembled fuel cell system including a battery module and an inverter module.

[0026] FIGS. 7A-7C are perspective views of a fuel cell system of the present teachings showing the addition of an inverter module to the fuel cell housing. FIG. 7 A is an exploded back, side view of the back end inverter module interface. FIG. 7B is a front, side view of the assembled fuel cell system including an inverter module having AC input terminals (or AC lugs) on an exterior side of the inverter module. FIG. 7C is a front, side view of the assembled fuel cell system including AC outlets on an exterior side of the inverter module.

[0027] FIG. 8 is a front, side perspective view of an assembled fuel cell system including an external power management module with DC power output including a primary DC output with load management and two secondary DC outputs with load management along an exterior side of the external power management module, and AC outlets on a front exterior face of the external power management module, which AC outlets can be individually managed to provide AC load management.

[0028] FIGS. 9A and 9B are perspective views of a fuel cell system of the present teachings showing the addition of an inverter module and a DC power management module to the fuel cell housing. FIG. 9A is an exploded front, side view of the front end fuel cell housing interface, the front end inverter module interface (with AC input terminals or AC lugs), and the front end DC power management module interface (with DC output). FIG. 9B is a front, side view of an assembled fuel cell system including an inverter module and a DC power management module.

[0029] FIGS. 10A and 10B are perspective views of a fuel cell system of the present teachings showing the addition of a battery module, an inverter module and a DC power management module to the fuel cell housing. FIG. 10A is an exploded front, side view of the front end fuel cell housing interface, the front end battery module interface, the front end inverter module interface, and the front end DC power management module interface. FIG. 1 OB is a front, side view of an assembled fuel cell system including a battery module, an inverter module, and a DC power management module.

[0030] FIGS. 11 A and 1 IB are front, side perspective views of an assembled fuel cell system of the present teachings including an inverter module and a DC power management module. FIG. 11 A includes a wireless controller on the front exterior face of the DC power management module. FIG. 1 IB includes a wireless controller and a touch screen controller on the front exterior face of the DC power management module.

[0031] FIG. 12 is a front, side perspective view of an assembled fuel cell system of the present teachings including a solar MPPT module.

[0032] FIG. 13 is a back, side perspective view of a fuel cell system showing its back end fuel cell housing interface along with the system exhaust outlet and the system air inlet.

[0033] FIGS. 14A-14C are perspective views of a fuel cell system of the present teachings including a filter module attached to the back end of the fuel cell housing. FIG. 14A is back, side view of an assembled fuel cell system including the filter module. FIG. 14B is a back, side cross-sectional view of the fuel cell system including the filter module (filter not shown so that side and top air vents have fluid communication with the system air inlet, which is within the filter module housing). FIG. 14C is a back, side exploded view of the filter module with filter and filter housing and interfaces between the back end fuel cell housing interface and the front end filter housing interface.

[0034] FIG. 15 is a back, side perspective view of a fuel cell system of the present teachings including a heat exchanger component mounted on the system exhaust outlet and system air inlet to pre-heat the air flowing into the fuel cell system.

[0035] FIG. 16A is a back, side perspective view of a fuel cell system of the present teachings including a heat exchanger component as shown in FIG. 15 and a fuel line in thermal communication with the system exhaust outlet. FIG. 16B is back, side perspective cross-sectional view of the heat exchanger component and fuel line in FIG. 16A, where the fuel line can be seen in thermal communications with the system exhaust outlet. FIG. 16C is a back, side perspective view of the heat exchanger component and fuel line of FIG. 16B, but with the fuel line being supplied from a source of fuel cell fuel and exiting into the system fuel inlet of the fuel cell system.

[0036] FIGS. 17 A is a back, side perspective view of a fuel cell system of the present teachings including a heat exchanger component and a fuel line as shown in FIGS. 16A-16C and also including a glycol fluid line (hash marked fluid line) in thermal communication with the system exhaust outlet. FIG. 17B is a back, side perspective cross-sectional view of the heat exchanger component, fuel line and glycol fluid line as shown in FIG. 17A.

[0037] FIG. 18 is a schematic diagram showing a use of a glycol fluid line to warm a fuel regulator and a fuel tank, where a liquid circulation pump is used to circulate the glycol fluid past the heat exchanger module and the fuel regulator and the fuel tank.

[0038] FIG. 19A is a back, side perspective view of an assembled fuel cell system of the present teachings including a heat exchanger / filter module attached to the back end of the fuel cell housing. FIG. 19B is a back, side exploded view of the heat exchanger / filter module of FIG. 19 A.

[0039] FIG. 20 is a back, side perspective view of an assembled fuel cell system of the present teachings including a fuel filter module.

[0040] FIG. 21 is a back, side perspective view of an assembled fuel cell system of the present teachings including a filter module and a vent termination with an adjustable exhaust locator at its distal end, where the adjustable exhaust locator can direct an exhaust stream from the system exhaust outlet (sideways as shown in the figure).

[0041] FIG. 22A is a back, side perspective view of an assembled fuel cell system of the present teachings including a termination adapter that extends the system exhaust outlet. The termination adapter comprises a termination adapter outlet in fluid communication with one or more of a fuel supply, a fuel regulator, a battery, and / or a structure housing one or more of a fuel supply, a fuel regulator, and a battery (as shown in FIG. 22B).

[0042] FIG. 23 is a front, side perspective view of an assembled fuel cell system of the present teachings including three battery modules and shock mounts located under the fuel cell housing and the exterior-most battery module.

[0043] FIG. 24A and 24B are front, side perspective views of a fuel cell system of the present teachings sitting on a slide mount, where FIG. 24A is in a collapsed position and FIG. 24B is in an extended position.

[0044] FIG. 25A is a front, side perspective view of a fuel cell system of the present teachings with a rain cover mounted on the fuel cell housing, which rain cover includes a rain cover extension. FIG. 25B is a front, cross-sectional view of a fuel cell system with a rain cover.

[0045] FIGS. 26A-26D are schematic diagrams of the various configurations of battery module(s) coupled to a fuel cell unit including in FIGS. 26C and 26D, the electrical communications between a fuel cell system and one or more battery module(s) (lightly shaded battery modules are optional) of a fuel cell system of the present teachings. FIG. 26A shows a battery attached to the front end fuel cell housing of the fuel cell system and can be 12 / 24 / 36 / 48V DC. FIG. 26B is a battery array, in a parallel arrangement, that is attached to the front end of a fuel cell housing of a fuel cell system and can be 12 / 24 / 36 / 48V DC.

[0046] FIG. 27 is a schematic diagram of a fuel cell system of the present teachings including one battery module, two optional battery modules (lightly shaded battery modules), a DC power management module, and a solar MPPT module.

[0047] FIG. 28 is a schematic diagram of the electrical communications among a fuel cell system of the present teachings including a battery module, an inverter module, two optional inverter modules (lightly shaded inverter modules), and a DC power management module.

[0048] FIG. 29 is a schematic diagram of the electrical communications and communications bus(s) links from the fuel cell system controller, which is a central processing unit (CPU) configured to operate the fuel cell system including a battery module and an inverter module and two optional inverter modules (lightly shaded inverter modules).

[0049] FIGS. 30A-30E are front view rough cross-sectional schematics of a battery module (FIG. 30A), a solar MPPT module (FIG. 30B), a DC power management module (FIG. 30C), an inverter module with the transfer switch located within the inverter module (FIG. 30D), and an inverter module with the transfer switch located outside the inverter module (FIG. 30E).

[0050] DETAILED DESCRIPTION

[0051] As described herein, the present teachings generally provide fuel cell systems that include a fuel cell housing containing a fuel cell unit, which fuel cell housing can be expanded with similar looking add-on modules and housings so that the resulting fuel cell system appears of like construction and is aesthetically appealing. Further, the add-on modules can be plugged into the exterior-most module for ease of installation and operation of the updated fuel cell system.

[0052] More specifically, the present teachings are related to fuel cell systems having a fuel cell housing that can be expanded, for example, on its front end with one or more battery modules, one or more inverter modules that may or may not include additional load management capability, a DC power management module and / or a solar MPPT such that the additional modules have the same cross-sectional shape and size as the fuel cell housing so it looks the same and is appealing to the consumer. In addition, front end interfaces and back end interfaces of the various modules are designed so that they can be interconnected or coupled in any order starting at the fuel cell housing interface. That is, one or more battery modules, one or more inverter modules that may or may not include additional load management capability, a DC power management module, an external power management module and a solar MPPT module can be added sequential to each other in any order provided that a solar MPPT module, if present, is the exterior-most module.

[0053] For example, a fuel cell system can be expanded with one or more battery modules, effectively making the product an integrated hybrid product. A primary driver for the battery is that is provides a lifeline as an energy source for use in a worst case scenario, for example, shutting down the system in the event of loss of the electrical grid. The fuel cell can operate on its own power for some time but after the fuel cell is unable to generate power, there’s a gap when the fuel cell is still too hot to shut down without potentially damage so the battery can provide energy during that gap to permit a proper shut down. However, not only is the battery available as a lifeline for the fuel cell system, but the battery module(s) can cover larger peaks in energy use by the customer. The additional energy storage of the battery also provides an opportunity for operation without the fuel cell system running. For example, the battery can be used and drained initially until a pre-set level is reached at which point the fuel cell unit starts up to provide power and / or recharge the battery(ies). If solar energy capacity is present, the solar energy can assist in recharging the battery, increasing the time between fuel cell cycles.

[0054] Moreover, the fuel cell system also can include additional auxiliary modules that are added to the back end of the fuel cell housing also in a plug-in style. The additional auxiliary modules can include a filter module, which can increase the filtering capacity of the fuel cell system in particularly dusty atmospheres or where air particles or chemical contaminants are present.

[0055] Another auxiliary module is a heat exchanger module, which is in thermal communication with the fuel cell system exhaust outlet to transfer heat from the exhaust to the air entering the fuel cell unit thereby preheating the air before entering the fuel cell unit. Such a heat exchanger module can be attached to the back end of the fuel cell housing for use in cold weather environments. . In particularly cold environments, more than one heat exchanger module may be added to ensure that the fuel can operate at the preferred temperature.

[0056] The heat exchanger module can also include additional heat exchanging components such as a coiled fuel cell fuel line around the heat exchanger component in thermal communication with the system exhaust outlet to further transfer heat from the exhaust to incoming fuel cell fuel to preheat the fuel cell fuel, for example, before being vaporized for use by the reformer. The heat exchanger module can also include a glycol fluid line loop that can be coiled around the heat exchanger component in thermal communication with the system exhaust outlet for passing by and heating a fuel tank regulator and / or a fuel tank for extremely cold weather conditions.

[0057] Yet another auxiliary module is a fuel filter module, which usually is the exterior- most module on the back end of the fuel cell housing. The fuel filter module can be helpful to remove contaminants such as sulfur from the fuel cell fuel prior to its use by the fuel cell unit.

[0058] To facilitate an understanding of the present invention, a number of terms and phrases are defined below.

[0059] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The abbreviations used herein have their conventional meaning within the chemical arts.

[0060] Throughout the description, where systems are described as having, including, or comprising specific components, or where processes and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are systems of the present invention that consist essentially of, or consist of, the recited components, and that there are processes and methods according to the present invention that consist essentially of, or consist of, the recited processing steps.

[0061] In the application, where an element or component is said to be included in and / or selected from a list of recited elements or components, it should be understood that the element or component can be any one of the recited elements or components, or the element or component can be selected from a group consisting of two or more of the recited elements or components.

[0062] Further, it should be understood that elements and / or features of an apparatus or a method described herein can be combined in a variety of ways without departing from the spirit and scope of the present invention, whether explicit or implicit herein. For example, where reference is made to a particular component of a system, that component can be used in various embodiments of systems of the present invention and / or in methods of the present invention, unless otherwise understood from the context. In other words, within this application, embodiments have been described and depicted in a way that enables a clear and concise application to be written and drawn, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the present teachings and invention(s). For example, it will be appreciated that all features described and depicted herein can be applicable to all aspects of the invention(s) described and depicted herein.

[0063] The articles “a” and “an” are used in this disclosure to refer to one or more than one (i.e., to at least one) of the grammatical object of the article, unless the context is inappropriate. By way of example, “an element” means one element or more than one element.

[0064] The term “and / or” is used in this disclosure to mean either “and” or “or” unless indicated otherwise.

[0065] It should be understood that the expression “at least one of’ includes individually each of the recited objects after the expression and the various combinations of two or more of the recited objects unless otherwise understood from the context and use. The expression “and / or” in connection with three or more recited objects should be understood to have the same meaning unless otherwise understood from the context.

[0066] The use of the term “include,” “includes,” “including,” “have,” “has,” “having,” “contain,” “contains,” or “containing,” including grammatical equivalents thereof, should be understood generally as open-ended and non-limiting, for example, not excluding additional unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0067] Where the use of the term “about” is before a quantitative value, the present invention also includes the specific quantitative value itself, unless specifically stated otherwise. As used herein, the term “about” refers to a ±10%, ±5%, ±3% or ±2% variation from the nominal value unless otherwise indicated or inferred from the context.

[0068] At various places in the present specification, variable or parameters are disclosed in groups or in ranges. It is specifically intended that the description include each and every individual subcombination of the members of such groups and ranges. For example, an integer in the range of 0 to 40 is specifically intended to individually disclose 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, and 40, and an integer in the range of 1 to 20 is specifically intended to individually disclose 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.

[0069] The use of any and all examples, or exemplary language herein, for example, “such as” or “including,” is intended merely to illustrate better the present invention and does not pose a limitation on the scope of the invention unless claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the present invention.

[0070] Terms and expressions indicating spatial orientation or altitude such as “upper,” “lower,” “top,” “bottom,” “front,” “back,” “horizontal,” “vertical,” and the like, unless their contextual usage indicated otherwise, are to be understood herein as having no structural, functional, or operational significance and as merely reflecting the arbitrarily chosen orientation of the various views of apparatus, devices, components, and features of the present teachings that may be illustrated in certain of the accompanying figures.

[0071] As a general matter, formulations specifying a percentage are by weight unless otherwise specified. Further, if a variable is not accompanied by a definition, then the previous definition of the variable controls.

[0072] As used herein, “in thermal communication with” refers to thermal communication between or among various components and / or structure such that heat transfer can occur between or among the components and / or structure.

[0073] As used herein, a “fuel cell stack” refers to the component of a fuel cell unit or fuel cell system where the electrochemical reaction takes place to convert hydrogen or electrochemically-oxidizable species to electricity. The fuel cell stack includes cells comprised of an anode, a cathode, and an electrolyte, often formed in layers. In operation, hydrogen and any other electrochemically oxidizable component(s) of a reformate entering a fuel cell stack, for example, from a reformer and / or a fluid mixing device, combine with oxygen anions within an anode layer of the fuel cell stack to produce water and / or carbon dioxide and electrons (electricity). The electrons generated within the anode layer migrate through the external load and back to the cathode layer where oxygen combines with the electrons to provide oxygen anions which selectively pass through the electrolyte layer and the anode layer.

[0074] As used herein, a “fuel cell unit” generally refers to a reformer, a fuel cell stack, and an afterburner. A fuel cell unit can include a vaporizer, where an outlet of the vaporizer is in operable fluid communication with an inlet of the reformer and / or the fuel cell stack. The reformer produces hydrogen from a hydrocarbon source, which reformation usually also produces carbon dioxide as a by-product. A fuel cell unit can include various valve assemblies, sensor assemblies, conduits, pumps, blowers and other components associated with such a unit, which other components can be considered the “balance of plant.” The balance of plant can also include pumps, heat exchangers, gaskets, compressors, recirculation blowers, and / or humidifiers. As used herein, “fuel cell system” generally refers to a fuel cell unit and the balance of plant. A fuel cell system often includes a plurality of fuel cell units. A plurality of fuel cell units can share the balance of plant. It should be understood that a “fuel cell unit” and a “fuel cell system” can be used interchangeably herein unless the context dictates otherwise. Moreover, it should be understood that known and conventional fuel cells come in a variety of types and configurations including phosphoric acid fuel cells (PAFCs), alkaline fuel cells (AFCs), polymer electrolyte membrane (or proton exchange membrane) fuel cells (PEMFCs), and solid oxide fuel cells (SOFCs). A fuel cell system generally refers to a fuel cell housing containing a fuel cell unit along with one or more modules as described herein.

[0075] In various embodiments, the different modules for the expansion of a front of a fuel cell system include a battery module, an inverter module, a DC power management module, and a solar MPPT module. The fuel cell system generally comprises a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end.

[0076] Turning to FIG. 1A, a fuel cell system 8 is shown, where a fuel cell unit and balance of plant (not shown) are contained in a fuel cell housing 10 having on a front end 12, a two piece front face plate 14, where a removeable upper front face plate 16 includes a handle insert 18 and a removeable lower front face plate 20 covers the front end fuel cell housing interface (see FIG. 2B). The front end of the fuel cell housing has a predetermined cross- sectional shape and size as shown by the crossed lines at the front of the fuel cell housing 22. The crossed lines 22 represent a plane that is perpendicular to the longitudinal axis of the fuel cell system 8 or housing 10. The predetermined cross-sectional shape and size of the fuel cell housing can vary greatly. That is, the predetermined cross-sectional shape and size of the fuel cell housing can be rectangular, square, circular, elliptical, or any other cross-sectional shape that is suitable for the fuel cell system. For example, in the examples provided in the figures of the present teachings, the predetermined cross-sectional shape of the fuel cell housing has six sides and appears as in FIG. 25B.

[0077] Returning to FIG. 1A. the fuel cell system 8 also includes shock mounts 24 located at the four bottom corners of the fuel cell system. The fuel cell system also includes a fuel cell system controller such as a CPU (25, not seen) located interior to the fuel cell housing usually near its front end away from the heat producing components,

[0078] FIG. IB shows a back end 26 of a fuel cell system 8, where a system exhaust outlet 28 and a system air inlet 30 can be seen protruding from the back end of the fuel cell system. Shock mounts 24 are also seen in this view, opposite the view in FIG. 1 A. FIG. 2 A shows another two-piece front face plate 14 without the handle insert on the upper front face plate. FIG. 2B shows that the lower portion of the removeable cover face plate was removed, which reveals a front end communications and signal bus 32 and a front end output DC power bus 34. The lower portion of the front end of the fuel cell housing also includes two front end locating features 36, 36’, which are holes in the fuel cell housing for modules added to the front end fuel cell housing interface. These front end features can be hidden with a blank face plate as shown in FIG. 2A. The front end communications and signal bus and the front end output DC power bus are configured to receive a back end communications and signal bus insert and a back end output DC power bus insert, respectively, from another module as described herein.

[0079] The front end of the fuel cell housing comprises a front end fuel cell housing interface configured to receive a back end battery module interface of a battery module, a back end inverter module interface of a inverter module that may or may not include additional load management capability, a back end DC power management module interface of a DC power management module, a back end external power management module interface of an external power management module, or a back end of a solar MPPT module interface of a solar MPPT module. Each of the battery module, the inverter module, the DC power management module, the external power management module, and the solar MPPT module have substantially the predetermined cross-sectional shape and size. When discussed herein, reference can be made to a predetermined cross-sectional shape and size of a housing or of a module, which reference can be used interchangeably herein unless the context other dictates. That is, each of the modules has substantially the same predetermined cross-sectional shape and size, which is equivalent to each of the housings of the modules.

[0080] In addition, the back end battery module interface, the back end inverter module interface, the back end DC power management module interface, the back end external power management module interface, or the back end solar MPPT module interface can plug into the front end fuel cell housing interface. In certain embodiments, the battery module, the inverter module, the DC power management module, the external power management module, or the solar MPPT module is plugged into the front end fuel cell housing interface.

[0081] Because of the interchangeability of the modules of the present teachings, a front end of an exterior-most module is configured to receive a back end battery module interface, a back end inverter module interface, a back end DC power management module interface, a back end external power management module interface, or a back end solar MPPT module interface. For example, the battery module, the inverter module, the DC power management module, an external power management module, or the solar MPPT module can be plugged into the front end of the exterior-most module, provided that the solar MPPT module, when present, is an exterior-most module on the front end of the fuel cell system.

[0082] Further, a front end of a then-exterior-most module is configured to receive the back end battery module interface(s), the back end inverter module interface(s), the back end DC power management module interface(s), the back end external power management module interface(s), or the back end of a solar MPPT module interface. Because of the intercompatihility of the modules, any order or numbers of modules can be plugged into each other for a desired result. In some embodiments, the fuel cell system comprises one or more of four battery modules, one or more of three inverter modules, one DC power management module, one external power management module, and one solar MPPT module, in any order beginning from the fuel cell housing, provided that the one solar MPPT module, when present, is the exterior-most module on the front of the fuel cell system.

[0083] To assist with plugging in one module to another, each of the battery module(s), inverter module(s), the DC power management module, the external power management module, and the solar MPPT module comprise a front end locating feature and a back end locating feature, wherein the front end locating feature of one module aligns with the back end locating feature of another module to permit proper alignment of the components and interconnections between modules.

[0084] In some embodiments of the front end modules’ interfaces, the front end locating feature comprises an aperture defining a hole and the back end locating feature comprises a protrusion having the same outer cross-sectional shape and size to slide into the front end locating feature. In particular embodiments, the front end locating feature comprises four front end locating features and the back end locating feature comprises four back end locating features, where each of the four front end locating features aligns with a respective one of the back end locating features. When four front end locating features and four back end locating features are used, they are generally placed in the corner areas of each module housing for ease and precision of alignment.

[0085] Given the general description of and connection of the different modules to a fuel cell system, the following will describe more specific designs and construction of various embodiments of expanded fuel cell systems of the present teachings.

[0086] For example, the present teachings provide a fuel cell system including one, two or three battery modules connected to the front end of the fuel cell housing physically in series. The fuel cell system generally comprises a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end. The front end of the fuel cell housing comprises a front end fuel cell housing interface configured to receive a back end first battery module interface of a first battery module having substantially the predetermined cross-sectional shape and size, wherein the back end first battery module interface can plug into the front end fuel cell housing interface. In some embodiments, the fuel cell system comprises the first battery module.

[0087] To that end, FIGS. 3A-3C show the attachment of a battery module to the front end fuel cell housing interface. In particular, FIG. 3A, an exploded view, shows that the battery module 38 has substantially the same predetermined cross-sectional shape and size as the fuel cell housing 10. The front end fuel cell housing interface 40 includes a front end communications and signal bus 32, a front end output DC power bus 34, and four front end locating features 36, 36’, 36”, 36” ’. FIG. 3 A also shows how similar the front end battery module interface 42 is to the front end fuel cell housing interface 40 including a back end locating feature 48’.

[0088] FIG. 3B shows a back, side view of the same exploded view of the fuel cell housing and the battery module 38. A back end of the battery module includes a back end battery module interface 50. The back end battery module interface 50 includes a back end communications and signal bus insert 44, a back end output DC power bus insert 46, and back end locating features 48, 48’, 48”, 48’”, the latter of which are protrusions of the same shape as the front end locating features that are holes. As can be envisioned, the back end battery module interface can plug into the front end fuel cell housing interface, creating an assembled fuel cell system with an added battery module as shown in FIG. 3C.

[0089] In certain embodiments, the first battery module comprises a front end first battery module interface configured to receive a back end second battery module interface of a second battery module having substantially the predetermined cross-sectional shape and size. Here, as with other modules, the back end second battery module interface can plug into the front end first battery module interface.

[0090] Further, the second battery module comprises a front end second battery module interface configured to receive a back end third battery module interface of a third battery module having substantially the predetermined cross-sectional shape and size. The back end third battery module interface can plug into the front end second battery module interface. In various fuel cell systems of the present teachings, the fuel cell system comprises the second battery module, and optionally, the third battery module. FIGS. 4A-4C are similar to FIGS. 3A-3C but with another (second) battery module 38’. FIG. 4 A is front, side exploded perspective view of the two battery module system. As can be seen, each of the front end fuel cell housing interface 40 and the front end battery housing interfaces 42, 42’ are similar. FIG. 4B is a back, side exploded perspective view of the two battery module system. As can be seen, the back end battery module interfaces 50, 50’ are similar to each other for aligning with the other modules and the front end fuel cell system interface. FIG. 4C shows the assembled two battery module fuel cell system. As would be appreciated, removeable upper and lower front face plates could be secured to an exterior face of the exterior-most module interface (here, 42’) in any of the configurations disclosed herein. Alternatively, a single front face plate could be affixed to the front end of the exterior-most module interface (here, 42’) in any of the configurations disclosed herein.

[0091] FIGS. 5A-5C are similar to FIGS. 3A-3C and FIGS. 4A and 4B, but with another (third) battery module 38”. FIG. 5 A is front, side exploded perspective view of the three battery module system. As can be seen, each of the front end fuel cell housing interface 40 and the front end battery housing interfaces 42, 42’, 42” are similar. FIG. 5B is a back, side exploded perspective view of the three battery module system. As can be seen, the back end battery module interfaces 50, 50’, 50” are similar to each other for aligning with the other modules and the front end fuel cell system interface. FIG. 5C shows the assembled three battery module fuel cell system.

[0092] In some embodiments, an inverter module, that may or may not include additional load management capability, is desired to be a part of the fuel cell system. An inverter module can include at least one of AC input terminals (AC lugs) and AC outlet(s). The inverter module can be connected directly to the front end of the fuel cell housing, or be connected to one, two or three, or more battery modules connected to the front end of the fuel cell housing as described above. Reference is made to an “exterior battery module,” which refers to the exterior-most battery module that is present at the time of connecting the next module, for example, here, an inverter module. Thus, an exterior battery module can refer to the first battery module, the second battery module, or the third battery module as described herein, depending on how many battery modules are present. It should be understood that reference to an “exterior” module, no matter which module it is, refers to the exterior-most module that is present at the time of connecting the next module.

[0093] For example, FIGS. 6A-6C show an fuel cell housing connected to a battery module connected to an inverter module. FIG. 6A shows a front, side perspective view of an inverter module 52 having a front end inverter module interface 54, including a front end communications and signal bus 32, a front end output DC power bus 34, and four front end locating features 36, 36’, 36”, 36” ’. FIG. 6A also shows how similar the front end inverter module interface 54 is to the front end battery module interface 42 and the front end fuel cell housing interface 40. FIG. 6A also shows on an exterior side of the inverter module, AC input terminals (AC lugs) 56.

[0094] FIG. 6B shows a back, side perspective view of the battery module-inverter module arrangement as in FIG. 6 A. As can be seen in FIG. 6B, the back end inverter module interface 58 is similar to the back end battery module interface 50 for aligning with the front end of the battery module and the front end fuel cell system interface. FIG. 6C shows the assembled battery module-inverter module fuel cell system.

[0095] Accordingly, in some embodiments, an exterior battery module comprises a front end exterior battery module interface configured to receive a back end first inverter module interface of a first inverter module having substantially the predetermined cross-sectional shape and size, wherein the back end first inverter module interface can plug into the front end exterior battery module interface. In some embodiments, the fuel cell system comprises the first inverter module. In certain embodiments, the exterior battery module is the first battery module, the second battery module, or the third battery module.

[0096] As mentioned above, an inverter module can be directly connected to a fuel cell housing. FIGS. 7A-7C show an example of such a fuel cell system. FIG. 7A show a back, side view of the fuel cell system where the back end inverter module interface 58 is shown, where the same components and connectors are seen in the same locations on their interfaces. For example, a back end communications and signal bus insert 44, a back end output DC power bus insert 46, and four back end locating features 48, 48’ , 48’ ’ , 48” ’ . FIG. 7B shows the assembled fuel cell system including an inverter module, which has AC input terminals (AC lugs) 56 on an exterior side of the inverter module. As an alternative, FIG. 7C shows the assembled fuel cell system with an inverter module having multiple AC outlets 60 located on an exterior side of the inverter module / housing. The individual AC outlets can be individually managed to enable AC load management, for example, external AC load management for the inverter. When multiple inverters are present in the fuel cell system, each inverter can be individually managed to provide AC load management.

[0097] In particular embodiments, an external power management module is desired adjacent to the fuel cell system. That is, a fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, where the fuel cell housing has a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end external power management module interface (not shown in the figures but having the same back end module interface as the other modules) of an external power management module having substantially the predetermined cross- sectional shape and size, wherein the back end external power management module interface can plug into the front end fuel cell housing interface. In some embodiments, the fuel cell system includes the external power management module.

[0098] FIG. 8 shows an embodiment of the present teachings that is a fuel cell system including an external power management module as described above. Here, the external power management module 63 is connected directly to the fuel cell housing 10. As can be seen, as with the other modules described herein, the modules have substantially the (same) predetermined cross-sectional shape and size of the fuel cell housing. Of course, minor variations to this general concept are included within the present teachings. That is, slight variations in size and shape can be possible but keeping within an aesthetically appealing resulting fuel cell system.

[0099] FIG. 8 also shows the possible variations to the different modules that can be present in the fuel cell systems of the present teachings. For example, the external power management module 63 includes AC outlets 60 on its front end external power management module interface 71. The AC outlets can be individually managed to provide AC load management. However, the AC outlets might not be active without an inverter module present (not shown). The front exterior face also includes front end communications and signal bus 32. In addition, the front exterior face includes a blank out cover plate for the front end output DC power bus so that it is not seen, and likely would be the exterior most module as its output DC power bus is not exposed.

[0100] The external power management module 63 also includes a DC power output 64 on an exterior side of the external power management module (or external power management module housing). The DC power output 64 includes a primary DC output with load management 66; and two secondary DC output with load management 68, 68’. Accordingly, the external power management module can include both AC power (load) management and DC power (load) management.

[0101] Some fuel cell system configurations include a solar MPPT module, for connecting the fuel cell system to solar power capabilities. The solar MPPT module can be connected to a first battery module, a second battery module or a third battery module. Accordingly, in some embodiments, the fuel cell system has an exterior battery module comprising a front end exterior battery module interface configured to receive a back end solar MPPT module interface (not shown in the figures but having the same back end module interface as the other modules) of a solar MPPT module having substantially the predetermined cross- sectional shape and size. The back end solar MPPT module interface can plug into the front end exterior battery module interface. In various embodiments, the fuel cell system comprises the solar MPPT module. In some embodiments, the exterior battery module is the first battery module, the second battery module, or the third battery module. In this configuration, it may be possible for the incoming solar energy to recharge the battery(ies).

[0102] In some embodiments, a solar MPPT module can be added to the exterior-most module that is a DC power management module. That is, the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size. The back end solar MPPT module interface can plug into the front end DC power management module interface. In some embodiments, the fuel cell system includes the solar MPPT module.

[0103] In some configurations, a DC power management module is desired adjacent to one or more inverter module(s). The DC power management module can include a DC power output. In various embodiments, the DC power output comprises a primary DC output with load management and one or more secondary DC outputs with load management, which can enable certain loads to be switched on and off to manage load while protecting the primary loads on a separate circuit. The DC power management module can also including different DC rail options, for example, primarily 48V, with optional 28V, 12V, and / or 5V rails. The different voltage options enables connection of different voltage level DC loads to the fuel cell unit. Accordingly, an exterior inverter module comprising a front end exterior inverter module interface configured to receive a back end DC power management module interface (not shown in the figures but having the same back end module interface as the other modules) of a DC power management module having substantially the predetermined cross- sectional shape and size. The back end DC power management module interface can plug into the front end exterior inverter module interface. In some embodiments, the fuel cell system comprises the DC power management module. As described above, the exterior inverter module can be the first inverter module, the second inverter module, or the third inverter module.

[0104] Accordingly, in certain embodiments, fuel cell system of the present teachings can include an inverter module 52 and a DC power management module 62 as shown in FIG 9A. More specifically, FIG. 9A shows a front, side exploded view of the fuel cell system exposing the front end fuel cell housing interface 40, the front end inverter module interface 54, and the front end DC power management interface 70. FIG. 9B shows the assembled fuel cell system including an inverter module 52 and a DC power management module 62.

[0105] In certain configurations, a solar MPPT module is desired to be adjacent to one or more inverter module(s). In this case, an exterior inverter module comprising a front end exterior inverter module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size. The back end solar MPPT module interface can plug into the front end exterior inverter module interface. In some embodiments, the fuel cell system comprises the solar MPPT module. As described above, the exterior inverter module can be the first inverter module, the second inverter module, or the third inverter module.

[0106] In yet other configurations, a solar MPPT module is added to the system, connecting to a DC power management module. Here, the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size. The back end solar MPPT module interface can plug into the front end DC power management module interface. In some embodiments, the fuel cell system comprises the solar MPPT module.

[0107] Other variations of configurations include having a DC power management module adjacent to one or more battery modules. For example, an exterior battery module comprising a front end exterior battery module interface configured to receive a back end DC power management module interface of a DC power management module having substantially the predetermined cross-sectional shape and size. The back end DC power management module interface can plug into the front end exterior battery module interface. In some embodiments, the fuel cell system includes the DC power management module. In certain embodiments, the exterior battery module is the first battery module, the second battery module, or the third battery module. In various embodiments, the fuel cell system also include an inverter module.

[0108] FIGS. 10A and 10B depict a fuel cell system including a battery module 38, an inverter module 52 and a DC power management module 62, where the front end fuel cell housing interface 40, the front end battery module interface 42, the front end inverter module interface 54, and the front end DC power management module interface 70 are shown. Each of the modules is plugged into the other modules as described herein. It may be desired to add a solar MPPT module after the DC power management module. In such a case, the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size. The back end solar MPPT module interface can plug into the front end DC power management module interface. In some embodiments, the fuel cell system comprises the solar MPPT module.

[0109] As mentioned above, an inverter may be directly connected to the front of the fuel cell housing. Consequently, a fuel cell system including a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size. The fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end first inverter module interface of a first inverter module having substantially the predetermined cross-sectional shape and size. The back end first inverter module interface can plug into the front end fuel cell housing interface. In some embodiments, the fuel cell system comprises the first inverter module.

[0110] A solar MPPT module may be desired adjacent to a lone inverter module, for example, a first inverter module. The first inverter module generally comprises a front end first inverter module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size. The back end solar MPPT module interface plugs into the front end first inverter module interface. In some embodiments, the fuel cell system comprises the solar MPPT module.

[0111] Alternatively, a DC power management module may be desired adjacent to a lone inverter module, for example, a first inverter module. Here, the first inverter module comprises a front end first inverter module interface configured to receive a back end DC power management module interface of a DC power management module having substantially the predetermined cross-sectional shape and size. The back end DC power management module interface can plug into the front end first inverter module interface. In some embodiments, the fuel cell system includes the DC power management module.

[0112] In various embodiments, a solar MPPT module is desired adjacent to a DC power management module, for example, with the above described configuration. Accordingly, the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size. The back end solar MPPT module interface can plug into the front end DC power management module interface. In some embodiments, the fuel cell system comprises the solar MPPT module.

[0113] The fuel cell systems of the present teaching further comprise a fuel cell system controller, wherein the fuel cell system controller is a central processing unit (CPU). The CPU can be configured to operate the fuel cell system including the fuel cell unit and to recognize the presence of one or more battery modules, one or more inverter modules, a DC power management module, an external power management module, and a solar MPPT module, and integrate the one or more battery modules, one or more inverter modules, a DC power management module, an external power management module, and a solar MPPT module to operate the fuel cell system, including any auxiliary modules attached to the back end of the fuel cell housing or system. The CPU can accomplish the identification, integration and operation of the various modules through the connection of the front end communications and signal bus(s) and front end output DC power bus(s) with the back end communications and signal bus(s) insets and back end output DC power bus(s) inserts, respectively, of the connected modules. The CPU is often located near the front end of the fuel cell housing, away from the heating generating components of the fuel cell unit. The CPU can also control a liquid circulation pump, if present as part of a glycol fluid loop.

[0114] For ease of control of a fuel cell system, it can include, on a front end exterior face plate of a front end of an exterior-most module, a wireless controller located on the exterior face plate, wherein the wireless controller is configured to be in communication with the fuel cell system controller to operate the fuel cell system. The wireless controller enables the fuel cell system to communicate with its various components and modules, and permits remote access via an App, for example, on a cell phone. In addition, a cellular module or component can be present and associated with the wireless controller to provide cell tower access, for example, 4G or 5G, so the fuel cell system controller or CPU can be accessed in the field without the internet. The front end exterior face plate of a front end of an exterior-most module can also include or just include a touch pad controller located on the exterior face plate, wherein the touch pad controller is configured to be in communication with the fuel cell system controller to operate the fuel cell system. The touch pad controller offers more direct access to the operation of the fuel cell system.

[0115] FIGS. 11 A and 1 IB depict a front face of an exterior-most module (here, a DC power management module) having a wireless controller 72 (FIG. 11 A), or a wireless controller 72 and a touch pad controller 74 (FIG. 1 IB). The wireless controller and the touch pad controller can be configured to be in communication with the fuel cell system controller or CPU to operate the fuel cell system. The wireless controller and / or the touch screen controller can be placed on most any exterior-most module. The cellular module or controller (not shown) can be associated with the wireless controller 72 or be independently present and in communication with the wireless controller.

[0116] For aesthetics, a front end of an exterior-most module can include a blank removeable cover face plate. In some embodiments, the blank removable cover face plate comprises two pieces, wherein one of the two pieces is a terminal wiring cover located on a lower portion of the front end of the exterior-most module.

[0117] In yet another variation of a configuration, a solar MPPT module is connected directly to the fuel cell housing of the fuel cell system. More specifically, a fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross- sectional shape and size, where the fuel cell housing has a front end and a back end. The front end comprises a front end fuel cell housing interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end fuel cell housing interface. In some embodiments, the fuel cell system includes the solar MPPT module.

[0118] FIG. 12 is an assembled fuel cell system including a solar MPPT module. The front end solar MPPT module interface 77 includes a front end communications and signal bus 32, a front end output DC power bus 34, and four front end locating features 36, 36’ , 36” , 36” ’ . The solar MPPT module also includes on an exterior side of the solar MPPT housing a solar power input component 76, which includes single solar array positive and negative connections 78, permitting connection to a solar power source.

[0119] In other configurations, more than one inverter module is desired, for example, three inverter modules. In such fuel cell systems where a first inverter is already connected to the fuel cell system, the first inverter module comprises a front end first inverter module interface configured to receive a back end second inverter module interface of a second inverter module having substantially the predetermined cross-sectional shape and size. The back end second inverter module interface can plug into the front end first inverter module interface. And the second inverter module comprises a front end second inverter module interface configured to receive a back end third inverter module interface of a third inverter module having substantially the predetermined cross-sectional shape and size. Here, similarly, the back end third inverter module interface plugs into the front end second inverter module interface. As described above, the fuel cell system can include the second inverter module, and optionally, the third inverter module. In such fuel cell systems with more than one inverter, each inverter can be individually managed thereby providing AC load management capabilities.

[0120] With respect to the interfaces of the various modules that can plug into each other, each module present in the fuel cell system generally comprises a front end communications and signal bus, a front end output DC power bus, a front end locating feature, a back end communications and signal bus insert, a back end output DC power bus insert, and a back end locating feature. Tn this way, a front end communications and signal bus of a module plugs into a back end communications and signal bus insert of another module; and a front end output DC power bus plugs into a back end output DC power bus insert. Further, to assist with alignment of these features and the compatible predetermined cross-sectional shape and size of modules and / or their housings, the modules include one or more front end locating features, which can be an aperture defining a hole. The modules also include one or more back end locating features which can be a protrusion having the same outer cross-sectional shape and size to slide into the front end locating features. Any number of locating features an be present, for example, one, two, three, four, five, six, or more; however, three or four locating features are typically used as the minimum number for an accurate, easy alignment.

[0121] Having discussed the various modules and their connections to the front end of the fuel cell, the back end of the fuel cell also has different modules that are applicable to it, principally for addressing different environmental conditions such as cold weather and / or dusty conditions as well as to decontaminate the fuel cell fuel before use by the fuel cell unit. These modules can include a heat exchanger module, a filter module, a heat-exchanger / filter module, and a fuel filter module. The heat exchanger module and the heat exchanger / filter module can also include a fuel line and / or a glycol fluid line in connection with the heat exchanger component to take advantage of the heat exhausted by the fuel cell system.

[0122] FIG. 13 depicts the back end of the fuel cell system including a system exhaust outlet 28 and a system air inlet 30. The back end fuel cell housing interface 92 also includes four back end locating features 48, 48’, 48”, 48” ’ as well as a fuel line access hole 80 for a fuel line to be connected to the fuel cell unit (not shown) inside the fuel cell housing. It should be understood that the front end locating features and the back end locating features remain on the same interfaces; however, when discussing the modules or housings attached to the back end of the fuel cell housing, the specific structure of the locating features can be reversed. That is, as shown in the figures of the back end added modules, the back end locating features can be holes while the front end locating features can be protrusions that fit into the holes. In particularly dusty areas or where a lot of particulate matter is in the environment, the fuel cell system can be adapted to include a filter module, which will add additional filter capacity to the fuel cell system. In various embodiments, a filter module comprises a filter housing having substantially the predetermined cross-sectional shape and size. The filter housing comprising apertures along a circumferential exterior surface of the filter housing defining air vents in the filter housing. The filter module also includes a filter positioned interior to the filter housing and adjacent to the air vents. As with other modules, a front end filter housing / module interface plugs into the back end fuel cell housing interface.

[0123] Here, for the back end add modules, reference may be made to the front or back end housing interface, which can be equivalent to the front or the back end module interface, respectively, as the housing and any associated structure and / or components are considered the “module” but connection to the back end fuel cell housing interface may be primarily by the housing of the module rather than a module that is self-contained.

[0124] As seen in FIGS. 14A-14C, the back end of fuel cell system can include a filter module 82, where the filter module includes a filter housing 84 that has substantially the predetermined cross-sectional shape and size. The filter housing includes apertures along the circumferential exterior surface(s) defining air vents 86 through the filter housing. A filter (not seen) can be positioned adjacent to the air vents in the interior of the filter housing so that incoming air through the air vents must pass through the filter before entering the fuel cell system. The back end of the filter housing also includes four back end locating features 48, 48’, 48”, 48”’ as well as a fuel line access hole 80 for a fuel line to be connected to the fuel cell unit (not shown) inside the fuel cell housing. The back end of the filter housing also includes a fuel line filler plug 88, which allows for easier maintenance of the modules.

[0125] It should be noted that the system exhaust outlet 28 extends beyond the back face of the filter housing through an aperture in the filter housing. As seen in the back, side cross- sectional perspective view of the filter module in FIG. 14B, the air incoming through the air vents 86 has a path or channel to the system air inlet 30 through the filter (not shown).

[0126] FIG. 14C shows a back, side exploded perspective view of the filter module 82 showing the filter 90, which has apertures 91 , 91 ’ , 91 ” , 91 ” ’ for fitting in the filter housing 84 and being placed adjacent to the back end fuel cell housing. FIG. 14C also shows the front end locating features 36, 36’ on the filter housing 84, which front end locating features are protrusions to fit into the respective back end locating features of the back end fuel cell housing interface 92. In various embodiments, the back end of the fuel cell housing comprises a system exhaust outlet and a system air inlet. This inlet and outlet are ripe for added modules. For example, a heat exchanger module comprising a heat exchanger housing having substantially the predetermined cross-sectional shape and size, the heat exchanger module comprising a heat exchanger component positioned in thermal communication with and adjacent to the system exhaust outlet to transfer heat from the system exhaust outlet and a front end of the heat exchanger housing plugs into the back end of the fuel cell.

[0127] The heat exchanger module includes a heat exchanger component that is made of two concentric annular portions, with radially projecting fins connecting the smaller annular portion to the larger annular portion. In use, the larger annular portion abuts the exterior perimeter of the system air inlet (e.g., circumferentially) and the smaller annular portion is in thermal communication with the system exhaust outlet (e.g., slidably adjacent to the system exhaust outlet) thereby permitting in- flowing air to pass through the space between the larger annular portion and the small annular portion and by the radially projecting fins. The smaller annular portion could be of varying length, thickness and materials of construction depending upon the amount of heat transfer that is desired. The same is true for the radially projecting fins, including the number of fins.

[0128] FIG. 15 shows a heat exchanger component 94 that has a larger annular portion 96 that fits around and abuts the system air inlet, and a smaller annular portion 98, which is in thermal communication with the system exhaust outlet thereby permitting air flowing into the fuel cell system to pass through the space between the larger annular portion and the smaller annular portion and by the radially projecting fins 100 that connect the larger annular portion to the smaller annular portion. The radially projecting fins are heated by the transfer of heat from the system exhaust outlet to the smaller annular portion to the fins, for increased surface face area and more efficient heat transfer. As stated herein, it should be understood that the dimensions, materials of construction, and number of fins can be varied for a particular application and amount of heat transfer desired.

[0129] Further, although not shown but illustrated in connection with a filter module (e.g., a heat exchanger / filter module), the heat exchanger component can be enclosed in a heat exchanger housing that together can form a heat exchanger module where the smaller annular portion 98 would protrude from the back of the heat exchanger housing.

[0130] For particularly cold weather applications, a heat exchanger module can further comprise a fuel cell fuel line in thermal communication with the system exhaust outlet to transfer heat from the system exhaust outlet to fuel cell fuel flowing through the fuel cell fuel line. In certain embodiments, the fuel cell fuel line coils around the smaller annular portion thereby in thermal communication with the system exhaust outlet. The fuel cell fuel line has a first end and a second end, where the first end is in fluid communication with a source of fuel cell fuel and the second end is in fluid communication with a fuel cell fuel inlet of the fuel cell system / unit.

[0131] FIGS. 16A-16C show a heat exchanger component 94 with a fuel line 102 in thermal communication with the system exhaust outlet. FIG. 16B is a back, side cross-sectional perspective view showing the fuel line 102 coiled around the smaller annular portion and adjacent to the system exhaust outlet 28. FIG. 16C shows a back side perspective view of the heat exchanger component with the fuel line 102, where a first end of the fuel line 104 is in fluid communication with a source of fuel cell fuel, e.g., a propane tank, or other source of reformable fuel (not shown) and a second end of the fuel line 106 is in fluid communication with a fuel cell fuel inlet of the fuel cell system through a fuel line access hole 80’.

[0132] In extremely cold weather environments, is may be desirable to heat the fuel and or fuel regulator using a glycol fluid loop. For example, the heat exchanger component can include or can also include a glycol fluid line in thermal communication with the system exhaust outlet to transfer heat from the system exhaust outlet to a glycol fluid flowing through the glycol fluid line. Similar to the fuel cell fuel line, the glycol fluid line can coil around the small annular portion thereby being in thermal communication with the system exhaust outlet. In this set-up, the glycol fluid line usually comprises a liquid circulation pump to circulate glycol fluid through the glycol fluid line. The glycol fluid line can be in thermal contact with a fuel regulator and / or a fuel tank whereby heated glycol fluid from the heat exchanger component is in thermal communication with the fuel regulator and / or the fuel tank thereby to heat the fuel regulator and / or the fuel tank.

[0133] FIGS. 17 A and 17B show the heat exchanger component 94 having a fuel line 102 present and also a glycol fluid line 108 (hashed tubing), which also is in thermal communication with the system exhaust outlet. FIG. 17B shows a back, side cross-sectional perspective view of this embodiment where the glycol fluid line 108 can be seen coiled around the smaller annular portion of the heat exchanger component. FIG. 17 A shows a first end of the glycol fluid line 1 10 and a second end of the glycol fluid line 112.

[0134] FIG. 18 shows where the first end and the second end can form a loop around a fuel regulator 114 and a fuel tank 116, for use in extremely cold weather conditions. A liquid circulation pump 118 controlled by the fuel cell unit CPU and powered by the fuel cell system can be used to circulate the glycol fluid. Here, because of use in extremely cold weather conditions, a glycol fluid, e.g. a fluid including or being a glycol is preferred to avoid freezing.

[0135] The fuel cell fuel line coiled around the smaller annular portion of the heat exchanger component and / or the glycol fluid loop coiled around the smaller annular portion of the heat exchanger component can be fixed in place, for example, welded in place with a coiled line cover or other structure that would hold the coiled line in place as one unit with the heat exchanger module, i.e., the fuel cell fuel line and / or the glycol fluid line can be one unit with the heat exchanger component defining the heat exchanger module.

[0136] Again in cold weather climates, the fuel cell system can further comprise a second heat exchanger module, connected in series with the heat exchanger module whereby the heat exchanger component is extended along the system exhaust outlet to transfer additional heat to the heat exchanger component. Alternatively or in addition, the smaller annular portion of the heat exchanger component can have a varying length, which impacts the thermal communication with the system exhaust outlet thereby permitting different amounts of heat to be transferred depending on the length of smaller annular portion.

[0137] In certain embodiments, the filter housing and the heat exchanger housing are one continuous unit forming a heat exchanger / filter housing of a heat exchanger / filter module, and a front end heat exchanger / filter housing / module interface can plug into the back end fuel cell housing interface. When used together, the filter module portion is usually adjacent to the back end of the fuel cell housing with the heat exchanger portion more outwardly positioned.

[0138] FIG. 19A depicts an assembled fuel cell system including a heat exchanger / filter module 120 connected to the back end fuel cell housing interface. FIG. 19A shows the heat exchanger component 94 extending beyond the back end heat exchanger / filter module interface 119. FIG. 19B shows an back, side exploded perspective view of the heat exchanger / filter module including a filter 90 and heat exchanger / filter housing 121, where a fuel line 102 can be seen to be part of this heat exchanger / filter module.

[0139] In other applications, a fuel filter module can be added to the back end fuel cell housing interface, which module is usually the exterior-most module located on the back of the fuel cell system. Here, a fuel filter module comprises a fuel filter housing having substantially the predetermined cross-sectional shape and size. The fuel filter modules comprises a fuel filter inlet in fluid communication with a fuel filter, interior to the fuel filter housing, and in fluid communication with a fuel filter outlet. The fuel filter outlet is in fluid communication with a system fuel inlet (usually through a fuel cell fuel line). Because the fuel filter module is usually the exterior-most module, the front end of the fuel filter housing can plug into the back end fuel cell housing interface, a back end heat exchanger housing / module interface, a back end heat exchanger / filter housing / module interface, or a back end filter housing / module interface. In various embodiments, the fuel filter comprises a sulfur filter.

[0140] FIG. 20 a back, side perspective view of an assembled fuel cell system of the present teaching including a fuel filter module 122 connected to the back end fuel cell housing interface. The fuel filter module includes a fuel filter inlet 124 connected to the fuel filter (not shown) internal to the fuel filter housing 130. The fuel filter module also includes a fuel filter outlet 126 that connects to a fuel hose 128 that the leads into the fuel cell fuel inlet 129 through the fuel line access hole 80 of the fuel cell system. The fuel filter can be present to mainly to remove sulfur from the fuel cell fuel but also can be effective at removing other contaminants in the fuel cell fuel.

[0141] As with the modules on the front of the fuel cell system, each of the heat exchanger module, the filter module, the heat exchanger / filter module, and the fuel filter module comprise a front end locating feature and a back end locating feature to assist in the alignment of the modules when plugging them in. In certain embodiments, the back end locating feature comprises an aperture defining a hole and the front end locating feature comprises a protrusion having the same outer cross-sectional shape and size to slide into the back end locating feature. In particular embodiments, the back end locating feature comprises four back end locating features and the front end locating feature comprises four front end locating features.

[0142] Because of needing the system exhaust outlet to be exposed from the exterior-most module, each of the heat exchanger housing, the filter housing, the heat exchanger / filter housing and the fuel filter housing, when present, comprises an aperture of the same shape and size as the system exhaust outlet to permit the system exhaust outlet to be in fluid communication with the surrounding environment.

[0143] In some embodiments, a fuel cell system further comprises a vent termination that extends the system exhaust outlet. In certain embodiments, the vent termination can be slip fit on the system exhaust outlet. The slip fit can be with a gasket or a more secure connection such as bolting, clipping and / or clamping. In particular embodiments, the vent termination comprises at its distal end an adjustable exhaust locator to direct an exhaust stream from the system exhaust outlet. The adjustable exhaust locator can be a rotational locator to route the exhaust stream in an appropriate direction. FIG. 21 shows an assembled fuel cell system including an filter module 82 and a vent termination 132 that extends the system exhaust outlet 28. The vent termination comprises at its distal end an adjustable exhaust locator 134 to direct an exhaust stream from the system exhaust outlet, for example, sideways as shown in FIG. 21.

[0144] In various embodiments, a fuel cell system further comprises a termination adapter that extends the system exhaust, wherein the termination adapter comprises a termination adapter outlet in fluid communication with one or more of a fuel supply, a fuel regulator, battery, and / or a structure housing one or more of a fuel supply, a fuel regulator, and a battery. Such use of the exhaust stream can circumvent or avoid the need for a glycol fluid loop and / or fuel cell fuel line adjacent the exhaust stream.

[0145] FIG. 22A is a back, side perspective view of a fuel cell system of the present teachings including a fdter module 82 and a termination adapter 136 that extends the system exhaust outlet 28. The termination adapter comprises a termination adapter outlet 138 in fluid communication with one or more of a fuel supply, a fuel regulator, battery, and / or a structure housing 140 one or more of a fuel supply, a fuel regulator, and a battery (see FIG. 22B for the last concept, where a structure housing vent 139 is included to permit flow of the heated exhaust through the structure housing).

[0146] In certain embodiments, the fuel cell system comprises shock mounts positioned on the bottom of the fuel cell housing and, optionally, on the bottom of one or more modules. FIG. 23 is a front, side perspective view of a fuel cell system of the present teachings including three battery modules 38, 38’ 38” and shock mounts 24, 24’, 24” located under the fuel cell housing 10 and the exterior- most battery module 38”

[0147] In particular embodiments, to assist with the servicing of the fuel cell system, the fuel cell system comprises a slide mount positioned beneath the fuel cell system, wherein the slide mount slidably moves the fuel cell system 8 from its place of operation. FIGS. 24A and 24B is a front, side perspective view of a fuel cell system of the present teachings sitting on a slide mount 142, shown in a collapsed position (FIG. 24A) and in an extended position (FIG. 24B).

[0148] In various embodiments, the fuel cell system comprises a rain cover that contours to the predetermined cross-sectional shape and size of the fuel cell housing and extends from the back end to the front end of the fuel cell system. The rain cover can have a tab along each side of the bottom of the rain cover to extend the rain cover underneath the fuel cell system. In some embodiments, the rain cover comprises a rain cover extension, that extends a top portion and a partial side portion of the rain cover, which can be useful to cover additional modules added to the fuel cell system. The rain cover can be fastened directly to the fuel cell housing and / or modules, if present, depending on the length requirements.

[0149] FIG. 25A is a front, side perspective view of a fuel cell system of the present teachings with a rain cover 144 including a rain cover extension 146. FIG. 25B is a front, cross-sectional view of a fuel cell system having a rain cover 144 that contours to the shape of the fuel cell housing 10. The rain cover 144 has mounts 148, 148’ that position the rain cover and secure it to the fuel cell housing.

[0150] Having described the various modules that can be added to a fuel cell system, the following figures depict the electrical and other communications between and among the various modules of the present teachings. FIGS. 26A and 26B are schematics of battery modules attached to the front end of a fuel cell housing / unit. FIGS. 26C and 26D are schematic diagrams of the electrical communications between a fuel cell system and one or more battery module(s) (lightly shaded battery modules are optional) of a fuel cell system.

[0151] FIG. 27 is a schematic diagram of a fuel cell system of the present teachings including one battery module, two optional battery modules (lightly shaded battery modules), a DC power management module, and a solar MPPT module. The DC power management module has a DC power output associated with it including a primary DC output with load management and two secondary DC output with load management. The solar MPPT module shows two photovoltaic array inputs into the module.

[0152] FIG. 28 is a schematic diagram of the electrical communications among a fuel cell system including a battery module, an inverter module, two optional inverter modules (lightly shaded inverter modules), and a DC power management module. The inverter modules are connected to the grid via internal transfer switches and also have outputs to electrical loads including a 120 V single phase output, a 120 / 240 V 2 phase output, and a 208 V 3 phase output.

[0153] FIG. 29 is a schematic diagram of the electrical communications and communications bus(s) links from the fuel cell system controller, which is a central processing unit (CPU) configured to operate the fuel cell system including a battery module and an inverter module and two optional inverter modules (lightly shaded inverter modules) Here, the inverter modules have one line the connects them to the electrical grid via an internal transfer switch located in each of the inverter modules. The inverter modules also are connected via a single line to electrical loads in 120 V single phase..

[0154] FIGS. 30A-30E are front view rough cross-sectional schematics of a battery module (FIG. 30A), a solar MPPT module (FIG. 30B), a DC power management module (FIG. 30C), an inverter module with the transfer switch located within the inverter module (FIG. 30D), and an inverter module with the transfer switch located outside the inverter module (FIG. 30E). An inverter module can also include an AC power management component, for example, with appropriate AC power management functionality located inside the inverter module (not shown). The schematics roughly show the internal components in each of the modules. In particular, the location of the front end communications and signal bus and the front end output DC power bus are in nearly identical locations for each module because the connection between the modules occurs primarily between these two components. That is, a front end of one bus connects into the corresponding back end bus insert of another module, which can occur for all modules where the CPU will identify, integrate and control or operate each individual module connected to the fuel cell system.

[0155] INCORPORATION BY REFERENCE

[0156] This application refers to various issued patents, published patent applications, journal articles, and other publications, all of which are incorporated herein by reference. If there is a conflict between any of the incorporated references and the instant specification, the specification shall control. In addition, any particular embodiment of the present disclosure that falls within the prior art may be explicitly excluded from any one or more of the claims. Because such embodiments are deemed to be known to one of ordinary skill in the art, they may be excluded even if the exclusion is not set forth explicitly herein. Any particular embodiment of the disclosure can be excluded from any claim, for any reason, whether or not related to the existence of prior art.

[0157] EQUIVALENTS

[0158] The disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting the disclosure described herein. Scope of the disclosure is thus indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. CLAIMS1. A fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end first battery module interface of a first battery module having substantially the predetermined cross-sectional shape and size, wherein the back end first battery module interface can plug into the front end fuel cell housing interface.

2. The fuel cell system of claim 1 , wherein the fuel cell system comprises the first battery module.

3. The fuel cell system of claim 1 or 2, wherein the first battery module comprises a front end first battery module interface configured to receive a back end second battery module interface of a second battery module having substantially the predetermined cross- sectional shape and size, wherein the back end second battery module interface can plug into the front end first battery module interface.

4. The fuel cell system of claim 3, wherein the second battery module comprises a front end second battery module interface configured to receive a back end third battery module interface of a third battery module having substantially the predetermined cross-sectional shape and size, wherein the back end third battery module interface can plug into the front end second battery module interface.

5. The fuel cell system of claim 3 or 4, wherein the fuel cell system comprises the second battery module, and optionally, the third battery module.

6. The fuel cell system of any one of claims 1-5, wherein an exterior battery module comprises a front end exterior battery module interface configured to receive a back end first inverter module interface of a first inverter module having substantially the predetermined cross-sectional shape and size, wherein the back end first inverter module interface can plug into the front end exterior battery module interface.

7. The fuel cell system of claim 6, comprising the first inverter module, optionally comprising AC load management.

8. The fuel cell system of claim 6 or 7, wherein the exterior battery module is the first battery module, the second battery module, or the third battery module.

9. The fuel cell system of any one of claims 1-5, wherein an exterior battery module comprises a front end exterior battery module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predeterminedcross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end exterior battery module interface.

10. The fuel cell system of claim 9, comprising the solar MPPT module.

11. The fuel cell system of claim 9 or 10, wherein the exterior battery module is the first battery module, the second battery module, or the third battery module.

12. The fuel cell system of any one of claims 6-8, wherein the first inverter module comprises a front end first inverter module interface configured to receive a back end second inverter module interface of a second inverter module having substantially the predetermined cross-sectional shape and size, wherein the back end second inverter module interface can plug into the front end first inverter module interface.

13. The fuel cell system of claim 12, wherein the second inverter module comprises a front end second inverter module interface configured to receive a back end third inverter module interface of a third inverter module having substantially the predetermined cross- sectional shape and size, wherein the back end third inverter module interface can plug into the front end second inverter module interface.

14. The fuel cell system of claim 12 or 13, comprising the second inverter module, and optionally, the third inverter module.

15. The fuel cell system of any one of claims 6-8 and 12-14, wherein an exterior inverter module comprises a front end exterior inverter module interface configured to receive a back end DC power management module interface of a DC power management module having substantially the predetermined cross-sectional shape and size, wherein the back end DC power management module interface can plug into the front end exterior inverter module interface.

16. The fuel cell system of claim 15, comprising the DC power management module.

17. The fuel cell system of claim 15 or 16, wherein the exterior inverter module is the first inverter module, the second inverter module, or the third inverter module.

18. The fuel cell system of any one of claims 6-8 and 12-14, wherein an exterior inverter module comprises a front end exterior inverter module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end exterior inverter module interface.

19. The fuel cell system of claim 18, comprising the solar MPPT module.

20. The fuel cell system of claim 18 or 19, wherein the exterior inverter module is the first inverter module, the second inverter module, or the third inverter module.

21. The fuel cell system of any one of claims 15-17, wherein the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end DC power management module interface.

22. The fuel cell system of claim 19, comprising the solar MPPT module.

23. The fuel cell system of any one of claims 1-5, wherein an exterior battery module comprises a front end exterior battery module interface configured to receive a back end DC power management module interface of a DC power management module having substantially the predetermined cross-sectional shape and size, wherein the back end DC power management module interface can plug into the front end exterior battery module interface.

24. The fuel cell system of claim 23, comprising the DC power management module.

25. The fuel cell system of claim 23 or 24, wherein the exterior battery module is the first battery module, the second battery module, or the third battery module.

26. The fuel cell system of any one of claims 23-25, wherein the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end DC power management module interface.

27. The fuel cell system of claim 26, comprising the solar MPPT module.

28. A fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end first inverter module interface of a first inverter module having substantially the predetermined cross-sectional shape and size, wherein the back end first inverter module interface can plug into the front end fuel cell housing interface.

29. The fuel cell system of claim 28, comprising the first inverter module.

30. The fuel cell system of claim 28 or 29, wherein the first inverter module comprises a front end first inverter module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end first inverter module interface.

31. The fuel cell system of claim 30, comprising the solar MPPT module.

32. The fuel cell system of claim 28 or 29, wherein the first inverter module comprises a front end first inverter module interface configured to receive a back end DC power management module interface of a DC power management module having substantially the predetermined cross-sectional shape and size, wherein the back end DC power management module interface can plug into the front end first inverter module interface.

33. The fuel cell system of claim 32, comprising the DC power management module.

34. The fuel cell system of claim 32 or 33, wherein the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end DC power management module interface.

35. The fuel cell system of claim 34, comprising the solar MPPT module.

36. A fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end DC power management module interface of a DC power management module having substantially the predetermined cross-sectional shape and size, wherein the back end DC power management module interface can plug into the front end fuel cell housing interface.

37. The fuel cell system of claim 36, comprising the DC power management module.

38. The fuel cell system of claim 36 or 37, wherein the DC power management module comprises a front end DC power management module interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end DC power management module interface.

39. The fuel cell system of claim 38, comprising the solar MPPT module.

40. A fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end solar MPPT module interface of a solar MPPT module having substantially the predetermined cross-sectional shape and size, wherein the back end solar MPPT module interface can plug into the front end fuel cell housing interface.

41. The fuel cell system of claim 40, comprising the solar MPPT module.

42. The fuel cell of any one of claims 1-41, wherein each module present in the fuel cell system comprises a front end communications and signal bus, a front end output DC power bus, a front end locating feature, a back end communications and signal bus insert, a back end output DC power bus insert, and a back end locating feature.

43. The fuel cell system of claim 42 wherein the front end locating feature comprises an aperture defining a hole and the back end locating feature comprises a protrusion having the same outer cross-sectional shape and size to slide into the front end locating feature.

44. The fuel cell system of claim 43, wherein the front end locating feature comprises four front end locating features and the back end locating feature comprises four back end locating features.

45. The fuel cell system of any one of claims 6-22 and 28-35, wherein the first inverter, the second inverter and / or the third inverter comprises at least one or AC input terminals (AC lugs) and AC outlets.

46. The fuel cell system of any one of claims 15-27 and 32-39, wherein the DC power management module comprises a DC power output.

47. The fuel cell system of claim 46, wherein the DC power output comprises a primary DC output with load management and one or more secondary DC outputs with load management.

48. A fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end battery module interface of a battery module, a back end inverter module interface of a inverter module, a back end DC power management module interface of a DC power management module, a back end external power management module interface of an external power management module, or a back end solar MPPT module interface of a solar MPPT module; wherein the battery module, the inverter module, the DC power management module, the external power management module and the solar MPPT module have substantially the predetermined cross-sectional shape and size, and the back end battery module interface, the back end inverter module interface, the back end DC power management module interface, the back end external power management module interface or the back end solar MPPT module interface can plug into the front end fuel cell housing interface.

49. The fuel cell system of claim 48 wherein the battery module, the inverter module, the DC power management module, the external power management module or the solar MPPT module is plugged into the front end fuel cell housing interface.

50. The fuel cell system of claim 49, wherein a front end of an exterior module is configured to receive a back end battery module interface, a back end inverter module interface, a back end DC power management module interface, a back end external power management module or a back end of a solar MPPT module interface.51 . The fuel cell system of claim 50, wherein the battery module, the inverter module, the DC power management module, the external power management module, or the solar MPPT module is plugged into the front end of the exterior module, provided that the solar MPPT module, when present, is an exterior-most module on the front of the fuel cell system.

52. The fuel cell system of claim 50 or 51, wherein a front end of a then exterior module is configured to receive the back end battery module interface(s), the back end inverter module interface(s), the back end DC power management module interface(s), the back end external power management module interface(s), or the back end solar MPPT module interface(s).

53. The fuel cell system of claim 52, wherein the fuel cell system comprises one or more of four battery modules, one or more of three inverter modules, one DC power management module, one external power management module, and one solar MPPT module, in any order beginning from the fuel cell housing, provided that the one solar MPPT module, when present, is the exterior-most module on the front of the fuel cell system.

54. The fuel cell system of any one of claims 48-53, wherein each of the battery module(s), inverter module(s), the DC power management module, the external power management module and the solar MPPT module comprise a front end locating feature and a back end locating feature, wherein the front end locating feature of one module aligns with the back end locating feature of another module.

55. The fuel cell system of claim 54, wherein the back end locating feature comprises an aperture defining a hole and the front end locating feature comprises a protrusion having the same outer cross-sectional shape and size to slide into the back end locating feature.

56. The fuel cell system of claim 55, wherein the back end locating feature comprises four back end locating features and the front end locating feature comprises four front end locating features, wherein each of the four back end locating features aligns with a respective one of the front end locating features.

57. A fuel cell system comprising a fuel cell unit contained in a fuel cell housing having a predetermined cross-sectional shape and size, wherein the fuel cell housing comprises a front end and a back end, the front end comprising a front end fuel cell housing interface configured to receive a back end external power management module interface of an external power management module having substantially the predetermined cross-sectional shape and size, wherein the back end external power management module interface can plug into the front end fuel cell housing interface.

58. The fuel cell system of claim 57, comprising the external power management module.

59. The fuel cell system of claim 58, wherein the external power management module comprises a DC power output and one or more AC outlets.

60. The fuel cell system of any one of claims 1-59, wherein the back end of the fuel cell housing comprises a system exhaust outlet and a system air inlet, and a heat exchanger module comprising a heat exchanger housing having substantially the predetermined cross- sectional shape and size, the heat exchanger module comprising a heat exchanger component positioned in thermal communication with and adjacent to the system exhaust outlet to transfer heat from the system exhaust outlet and a front end heat exchanger housing interface plugs into the back end fuel cell housing interface.

61. The fuel cell system of claim 60, wherein the heat exchanger component comprises two concentric annular portions, with radially projecting fins connecting the smaller annular portion to the larger annular portion, and the larger annular portion abuts the system air inlet and the smaller annular portion is in thermal communication with the system exhaust outlet thereby permitting inflowing air to pass through the space between the larger annular portion and the small annular portion and by the radially projecting fins.

62. The fuel cell system of claim 60 or 61, wherein the heat exchanger module further comprises a fuel cell fuel line in thermal communication with the system exhaust outlet to transfer heat from the system exhaust outlet to fuel cell fuel flowing through the fuel cell fuel line.

63. The fuel cell system of claim 62, wherein the fuel cell fuel line coils around the smaller annular portion thereby in thermal communication with the system exhaust outlet.

64. The fuel cell system of claim 63, wherein the fuel cell fuel line has a first end and a second end, the first end in fluid communication with a source of fuel cell fuel and the second end in fluid communication with a fuel cell fuel inlet of the fuel cell unit.

65. The fuel cell system of any one of claims 60-64, wherein the heat exchanger component further comprises a glycol fluid line in thermal communication with the systemexhaust outlet to transfer heat from the system exhaust outlet to a glycol fluid flowing through the glycol fluid line.

66. The fuel cell system of claim 65, wherein the glycol fluid line coils around the small annular portion thereby in thermal communication with the system exhaust outlet.

67. The fuel cell system of claim 66, wherein the glycol fluid line comprises a liquid circulation pump to circulate glycol fluid through the glycol fluid line, wherein the glycol fluid line is in thermal contact with a fuel regulator and / or a fuel tank whereby heated glycol fluid from the heat exchanger component is in thermal communication with the fuel regulator and / or the fuel tank thereby to heat the fuel regulator and / or the fuel tank.

68. The fuel cell system of any one of claims 60-67, wherein the fuel cell system further comprises a second heat exchanger module, connected in series with the heat exchanger module whereby the heat exchanger component is extended along the system exhaust outlet.

69. The fuel cell system of any one of claims 61-67, wherein the smaller annular portion of the heat exchanger component has a varying length which impacts the thermal communication with the system exhaust outlet thereby permitting different amounts of heat to be transferred.

70. The fuel cell system of any one of claim 60-69, further comprising a filter module comprising a filter housing having substantially the predetermined cross-sectional shape and size and comprising apertures along a circumferential exterior surface of the filter housing defining air vents in the filter housing; and a filter positioned interior to the filter housing and adjacent to the air vents, and a front end filter housing interface plugs into the back end fuel cell housing interface or the back end heat exchanger housing interface.

71. The fuel cell system of claim 70, wherein the filter housing and the heat exchanger housing are one continuous unit forming a heat exchanger / filter housing of a heat exchanger / filter module, and a front end heat exchanger / filter housing interface plugs into the back end fuel cell housing interface.

72. The fuel cell system of any one of claims 1-59, wherein the back end of the fuel cell housing comprises a system exhaust outlet and a system air inlet, and a filter module comprising a filter housing having substantially the predetermined cross-sectional shape and size and comprising apertures along a circumferential exterior surface of the filter housing defining air vents in the filter housing; and a filter positioned interior to the filter housing and adjacent to the air vents, and a front end filter housing interface plugs into the back end fuel cell housing interface.

73. The fuel cell system of any one of claims 1-72, wherein the back end of the fuel cell housing comprises a system exhaust outlet and a system air inlet, and a fuel filter module comprising a fuel filter housing having substantially the predetermined cross-sectional shape and size and comprising a fuel filter inlet in fluid communication with a fuel filter, interior to the fuel filter housing, and in fluid communication with a fuel filter outlet in fluid communication with a system fuel inlet, and a front end fuel filter housing interface plugs into the back end fuel cell housing interface, a back end heat exchanger housing interface, a back end heat exchanger / filter housing interface, or a back end filter housing interface.

74. The fuel cell system of claim 73, wherein the fuel filter comprises a sulfur filter.

75. The fuel cell system of any one of claims 60-74, wherein each of the heat exchanger module, the filter module, the heat exchanger / filter module, and the fuel filter module comprise a front end locating feature and a back end locating feature.

76. The fuel cell system of claim 75, wherein the back end locating feature comprises an aperture defining a hole and the front end locating feature comprises a protrusion having the same outer cross-sectional shape and size to slide into the back end locating feature.

77. The fuel cell system of claim 76, wherein the back end locating feature comprises four back end locating features and the front end locating feature comprises four front end locating features.

78. The fuel cell system of any one of claims 60-77, wherein each of the heat exchanger housing, the filter housing, the heat exchanger / filter housing and the fuel filter housing, when present, comprises an aperture of the same shape and size as the system exhaust outlet to permit the system exhaust outlet to be in fluid communication with the surrounding environment.

79. The fuel cell system of any one of claims 60-78, comprising a vent termination that extends the system exhaust outlet.

80. The fuel cell system of claim 79, wherein the vent termination can be slip fit on the system exhaust outlet.

81. The fuel cell system of claim 79 or 80, wherein the vent termination comprises at its distal end an adjustable exhaust locator to direct an exhaust stream from the system exhaust outlet.

82. The fuel cell system of claims 60-78, comprising a termination adapter that extends the system exhaust, wherein the termination adapter comprises a termination adapter outlet in fluid communication with one or more of a fuel supply, a fuel regulator, a battery, and / or a structure housing one or more of a fuel supply, a fuel regulator, and a battery.

83. The fuel cell system of any one of claims 1-82, further comprising a fuel cell system controller, wherein the fuel cell system controller is a central processing unit (CPU) configured to operate the fuel cell system including the fuel cell unit and to recognize the presence of one or more battery modules, one or more inverter modules, a DC power management module, an external power management module and a solar MPPT module, and integrate the one or more battery modules, one or more inverter modules, a DC power management module, an external power management module and a solar MPPT module to operate the fuel cell system.

84. The fuel cell system of any one of claims 1-83, wherein a front end exterior face plate of a front end of an exterior-most module comprises a wireless controller located on the exterior face plate, wherein the wireless controller is configured to be in communication with the fuel cell system controller to operate the fuel cell system.

85. The fuel cell system of any one of claims 1-84, wherein a front end exterior face plate of a front end of an exterior-most module comprises a touch pad controller located on the exterior face plate, wherein the touch pad controller is configured to be in communication with the fuel cell system controller to operate the fuel cell system.

86. The fuel cell system of any one of claims 1-85, wherein a front end of an exterior- most module comprise a blank removeable cover face plate.

87. The fuel cell system of claim 86 wherein the blank removable cover face plate comprises two pieces, wherein one of the two pieces is a terminal wiring cover located on a lower portion of the front end of the exterior module.

88. The fuel cell system of any one of claims 1-87, comprising shock mounts positioned on the bottom of the fuel cell housing and, optionally, on the bottom of one or more modules.

89. The fuel cell system of any one of claims 1-88, comprising a slide mount positioned beneath the fuel cell system, wherein the slide mount slidably moves the fuel cell system from its place of operation.

90. The fuel cell system of any one of claims 1-89, comprising a rain cover that contours to the predetermined cross-sectional shape and size of the fuel cell housing and extends from the back end to the front end of the fuel cell system, with a tab along each side of the bottom of the rain cover to extend the rain cover underneath the fuel cell system.

91. The fuel cell system of claim 90, wherein the rain cover comprises a rain cover extension, that extends a top portion and a partial side portion of the rain cover.

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