DESC:TECHNICAL FIELD
[0001] The present disclosure relates generally to the field of fuel-cell stack maintenance. In particular, the present disclosure relates to a cooling arrangement for fuel-cell stacks.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed disclosure, or that any publication specifically or implicitly referenced is prior art.
[0003] A fuel-cell is an energy converting device that converts chemical energy of a source fuel into electric energy through an electrochemical reaction, without converting the source fuel into heat energy. Fuel-cells may be utilized as power sources for vehicles and other industrial and domestic purposes.
[0004] Polymer electrolyte membrane fuel-cells (PEMFC) are currently most widely researched as fuel-cells for vehicles. A PEMFC is operated at a relatively low temperature on the order of 50-100 °C and they offer a faster start up time, faster power converting reaction time, and higher energy density, compared to other types of fuel-cells. However, each unit cell only generates a low voltage. To generate a higher voltage, several unit cells are stacked on one another to form a fuel-cell stack.
[0005] A fuel-cell stack includes a membrane-electrode assembly (MEA) as a main component. The MEA is positioned inside the stack and includes a solid electrolyte membrane that only allows movement of hydrogen ions, and electrode layers on either surface of the electrolyte membrane. The electrode layers include a cathode and an anode that are applied with a catalyst to ionise oxygen and hydrogen.
[0006] A gas diffusion layer (GDL) and a bipolar plate are placed at the outer portion of the MEA. The bipolar plate includes a flow field for the supply of a reaction gas (hydrogen as a fuel and oxygen or air as an oxidant). Also, cooling water is passed through the flow field.
[0007] The above construction forms a unit cell. A plurality of unit cells are stacked on one another and end plates are joined on the outmost portion thereof, thus completing a fuel-cell stack.
[0008] Hydrogen and oxygen or air are supplied to the anode and cathode, respectively. The hydrogen at the anode is reduced to protons which passes through the MEA towards the cathode. The electrons generated during this reaction traverses an external circuit. The protons react with the oxygen and the electrons at the cathode to form water. This reaction can be described as follows,

H2? 2H+ + 2e- (at the anode)
O2 + 4H+ + 4e-? 2H2O (at the cathode)

[0009] As fuel-cell stacks produce electrical energy, losses in the electrochemical reactions and electrical resistance in the components that make up the stack produce waste thermal energy (heat) that must be removed for the stack to maintain a constant optimal temperature. The PEM is often sensitive to high temperatures, such that the fuel-cell operating conditions must be maintained below these degradation temperatures.
[0010] Typically, the cooling system associated with a fuel-cell stack includes a circulation pump for circulating a single-phase liquid coolant through the fuel-cell stack to a heat exchanger where the waste thermal energy is transferred to the environment. The two most common coolants used are de-ionized water and a mixture of ethylene glycol and de-ionized water. Such liquid coolants are required to be circulated through the system in a relatively large volume to reject sufficient waste heat in order to maintain a constant stack operating temperature, particularly under maximum power conditions. A large amount of electrical energy is required to circulate the coolant, which reduces overall efficiency of the fuel-cell power system. To this end, it is desirable to reduce the amount of coolant needed to cool a fuel-cell stack and thereby reduce the amount of pumping power required.
[0011] There is, therefore, a need in the art for an arrangement to cool the fuel-cells within the stack effectively, while also providing for cooling of the heated coolant before it is recirculated into the fuel-cell stack. There is a further need for a cooling arrangement that is compact.
[0012] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0013] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the disclosure are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the disclosure may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0014] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0015] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the disclosure.
[0016] Groupings of alternative elements or embodiments of the disclosure disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS
[0017] A general object of the present disclosure is to provide a fuel-cell stack with a cooling arrangement.
[0018] Another object of the present disclosure is to provide a cooling arrangement for recirculating the coolant without a need for an external cooling apparatus.
[0019] Another object of the present disclosure is to provide a fuel-cell design with stamped passages to circulate reaction gases and coolant through the fuel-cell.
[0020] Another object of the present disclosure is to provide a radiator that is integrated into a mounting arrangement of the fuel cell stack assembly.
[0021] Another object of the present disclosure is to provide a radiator block that acts as a support and a housing to the fuel cell stack assembly.
[0022] Another object of the present disclosure is to provide a fuel-cell stack that is compact.
[0023] Another object of the present disclosure is to provide a radiator block that does not occupy additional space.

SUMMARY
[0024] The present disclosure relates generally to the field of fuel-cell stack maintenance. In particular, the present disclosure relates to a cooling arrangement for fuel-cell stacks.
[0025] In an aspect, the present disclosure provides a fuel-cell sack assembly, said assembly comprising: a fuel-cell stack; and a radiator block.
[0026] In another aspect, the fuel-cell stack assembly comprises: a plurality of fuel-cells stacked in series; one or more inlets for entry of a coolant to absorb heat from the plurality of fuel-cells; and one or more outlets for exit of the coolant.
[0027] In another aspect, the radiator block is configured to house the fuel-cell stack and has a plurality of channels configured on walls of the radiator block such that one end of the plurality of channels is coupled to the one or more outlets of the fuel-cell stack and other end of the plurality of channels is coupled to the one or more inlets of the fuel-cell stack.
[0028] In another aspect, the coolant flows from the one or more outlets of the fuel-cell stack to the one or more inlets of the fuel-cell stack by passing through the plurality of channels enables cooling of the coolant by heat exchange with an ambient atmosphere.
[0029] In an embodiment, the plurality of fuel-cells are stacked vertically and in the same orientation.
[0030] In another embodiment, the radiator block comprises a plurality of pillars configured as mounting support for the fuel-cell stack.
[0031] In another aspect, the plurality of channels configured on the radiator block are arranged in a serpentine configuration.
[0032] In another aspect, the plurality of channels configured on the radiator block are arranged in any or a combination of parallel and series configurations.
[0033] In another embodiment, the fuel-cell stack comprises at least two current collectors to extract the current produced by the plurality of fuel-cells.
[0034] In another embodiment, the fuel-cell stack comprises one or more inlets and corresponding one or more outlets configured for flow of hydrogen and any of air and/or oxygen for an anode and a cathode respectively of each of the plurality of fuel-cells.
[0035] In another embodiment, the fuel-cell stack comprises: a plurality of fuel-cells stacked in series; a plurality of cooling plates disposed at regular intervals in between the plurality of fuel-cells.
[0036] In another embodiment, each of the plurality of cooling plates comprises one or more channels, such that one end of the one or more channels is configured to receive coolant from the one or more inlets of the fuel-cell stack and the other end of the one or more channels is configured to discharge the coolant to the one or more outlets of the fuel-cell stack.
[0037] In another embodiment, the flow of the coolant on each of the plurality of cooling plates enables cooling of at least one thermally coupled of the plurality of fuel-cells.
[0038] In another embodiment, the one or more channels on each of the plurality of cooling plates are arranged in a serpentine configuration.
[0039] In another embodiment, the one or more channels on each of the plurality of cooling plates are arranged in any or a combination of parallel and series configurations.
[0040] In another embodiment, each of the plurality of fuel-cells comprises: two stamped plates configured to be electrodes, their flat surfaces facing each other, with at least one stamped plate configured to have a non-uniform topography such that a plurality of passages are formed by the arrangement of the two stamped plates.
[0041] In another embodiment, the one or more of the plurality of passages are adapted to allow flow of the coolant to enable cooling of the fuel-cell.
[0042] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0044] FIG. 1A illustrates an exemplary exploded view of a fuel-cell stack assembly with the proposed radiator block and fuel-cell stack, in accordance with an embodiment of the present disclosure.
[0045] FIG. 1B illustrates an exemplary representation of the proposed fuel-cell stack with a cooling plate, in accordance with an embodiment of the present disclosure.
[0046] FIG. 2A illustrates an exemplary representation of the proposed cooling plate with channels in a serpentine layout for the flow of a coolant, in accordance with an embodiment of the present disclosure.
[0047] FIGs. 2B and 2C illustrate exemplary representations of inlet and outlet flow paths respectively of the coolant in the proposed fuel-cell stack, in accordance with an embodiment of the present disclosure.
[0048] FIG. 2D illustrates an exemplary sectional view of the fuel-cell stack, on a side of inlet of coolant. The fuel-cell assemblies are displayed along with the proposed cooling plate, in accordance with an embodiment of the present disclosure.
[0049] FIG. 3A illustrates an exemplary exploded view of a fuel-cell stack assembly with proposed radiator block and fuel-cell stack, in accordance with an embodiment of the present disclosure.
[0050] FIG. 3B illustrates an exemplary representation of the assembly of fuel-cell stack and the proposed radiator block with channels on its walls for the circulation of coolant, in accordance with an embodiment of the present disclosure.
[0051] FIGs. 4A and 4B illustrate exemplary representations of the full assembly and section B-B respectively, of the fuel-cell stack along with the proposed radiator block, in accordance with an embodiment of the present disclosure.
[0052] FIGs. 4C and 4D illustrate exemplary representations of a closer view of the areas in section B-Bat a junction of the radiator channels and bottom and top end plates respectively, in accordance with an embodiment of the present disclosure.
[0053] FIG. 5A illustrates an exemplary representation of the fuel-cell assembly with proposed stamped plate, in accordance with an embodiment of the present disclosure.
[0054] FIG. 5B illustrates an exemplary exploded view of the fuel-cell assembly with the proposed stamped plate, in accordance with an embodiment of the present disclosure.
[0055] FIGs. 6A and 6B illustrate exemplary representations of the assembly and section P-P of fuel-cell respectively, with the proposed stamped plate, in accordance with an embodiment of the present disclosure.
[0056] FIG. 6C illustrates an exemplary representation of an area in section P-P that shows the fuel-cell assembly sandwiched between a pair of stamped plates, in accordance with an embodiment of the present disclosure.
[0057] FIG. 7A illustrates an exemplary representation of a transverse section of a fuel-cell stack showing anode and cathode plates formed by the stamped plates, in accordance with an embodiment of the present disclosure.
[0058] FIG. 7B illustrates an exemplary representation of a transverse section of the fuel-cell stack showing flow path of coolant and reaction gases in the channels formed by the stamp plates, in accordance with an embodiment of the present disclosure.
[0059] FIG. 8A illustrates exemplary representations of the proposed stamped plate showing the flow path, arranged in a serpentine layout, for the reaction gases and a straight flow path for the coolant, in accordance with an embodiment of the present disclosure.
[0060] FIG. 8B illustrates an exemplary exploded view of a fuel-cell stack assembly with the radiator block and the fuel-cell stack, in accordance with an embodiment of the present disclosure.
[0061] FIG. 8C illustrates an exemplary representation of a fuel-cell stack with the proposed stamped plate, indicating the flow paths, and inlet and outlet ports for the coolant and reaction gases, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0062] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0063] Each of the appended claims defines a separate disclosure, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "disclosure" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "disclosure" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0064] Various terms are used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0065] The present disclosure relates to a fuel-cell stack and a cooling arrangement for the fuel-cells that is integrated with the fuel-cell stack. In an aspect, the cooling arrangement is in the form of a plate that allows for circulation of a coolant around the fuel-cells. Heat generated by the reaction in the fuel-cells is exchanged with the coolant either by conduction or convection. In an embodiment of the present disclosure, a cooling plate is used, that is placed in between adjacent fuel-cells. The cooling plate contains channels for coolant to flow and the heat is exchanged by convection.
[0066] The present disclosure also relates to a fuel-cell stack assembly integrated with a radiator block to cool the circulating coolant. In an aspect of the present disclosure, the radiator block also forms the supporting structure for the fuel-cell stack assembly on which end plates are mounted. In an embodiment of the present disclosure, heat exchange channels are placed on the walls of the radiator block.
[0067] Referring to FIG. 1A, where an exploded view of a fuel-cell stack assembly (also referred to as assembly hereinafter) 100 is illustrated with the radiator block, the assembly comprises a fuel-cell stack 102 that is clamped between a top end plate 106-1 and a bottom end plate 106-2 (collectively referred to as end plates 106). The end plates 106 apply and maintain uniform pressure across the fuel-cell stack 102. To accomplish this, a clamping arrangement 108 can be utilized. The clamping arrangement 108 can be a part of the top end plate 106-1 alone or can be a part of both end plates 106. The clamping arrangement 108 can, in turn, includes a plurality of components that serve to apply and maintain uniform pressure across the fuel-cell stack 102. A radiator block 104 is also illustrated, which encloses the fuel-cell stack 102. The radiator block 104 comprises channels 306 (as shown in FIG. 3B) for the circulation of coolant. It also acts as a supporting structure for the fuel-cell stack assembly 100. The radiator block 104 also comprises a plurality of mounting pillars 304 that offer this support. In an embodiment of this disclosure, the number of mounting pillars 304 is six, disposed at the four corners and one each in the middle of sides W and Y of the radiator block 104.
[0068] Referring to FIG. 1B, where the fuel-cell stack 102 is illustrated in greater detail, the fuel-cell stack 102 comprising numerous fuel-cells stacked one over another and connected in series to obtain a higher cumulative voltage. The fuel-cell stack 102 is disposed of numerous electrodes-anode and cathode, separated by membrane electrode assemblies (MEA) that together constitute a fuel-cell. This fuel-cell assembly is further augmented by the presence of bipolar plates and gaskets which serve to support the fuel-cells and also supply the reaction gases and coolant. The fuel-cell stack 102, as illustrated in FIG. 1B, has a plurality of current collectors 116, which tap the potential generated by the fuel-cell stack 102. The fuel-cell stack 102 also comprises a plurality of ports for the inlet of hydrogen, oxygen and coolant, and a plurality of ports for outlet of the same. In accordance with an embodiment of this disclosure, the ports are located at the bottom of the fuel-cell stack 102.
[0069] Referring to FIG. 2A, where the cooling arrangement employed within the fuel-cell stack 102 is disclosed in accordance with an embodiment of this disclosure, the cooling arrangement comprises a conducting plate carrying channels for circulation of a coolant, that is disposed in between anode-cathode assemblies. In an embodiment of the present disclosure, the cooling plate 202 is arranged after two pairs of anode-cathode assemblies. The cooling plate 202 is a conducting plate that carries channels that allow for flow of coolant through them. The channels are designed to expose a maximum surface area of the coolant in order to enhance heat exchange. In an embodiment of the present disclosure, the channels can be in any or a combination of parallel and series configurations. In another embodiment, the channels can be in a serpentine configuration. The material of the cooling plate 202 can be conducting materials such as, but not limited to, stainless steel, aluminium, graphene etc.
[0070] FIG. 2B and 2C illustrate sections-view A and view B, respectively, of the fuel-cell stack 102 that depict the inlet 112-1 and outlet 112-2 of the coolant. FIG. 2D illustrates a section from view A in greater detail. The cooling plate 202 is disposed within the fuel-cell stack 102, after every two pairs of anode-cathode assemblies. The fuel-cell stack 102 consists of a common inlet 112-1 and outlet 112-2 for the coolant. Through the common inlet 112-1, the coolant enters the individual cooling plate 202, passes through the channel and exits the cooling plate 202 into the common outlet for the coolant 112-2. The heat exchange occurs at the serpentine channels. The hot coolant is then cooled as it is passed through the radiator 104 and then pumped into the fuel-cell stack 102 for re-circulation.
[0071] Referring to FIG. 3A, where an exploded view of a fuel-cell stack assembly is illustrated with the radiator block, in accordance with an embodiment of this disclosure, the assembly includes a fuel-cell stack 102 that is clamped between a top end plate 106-1 and a bottom end plate 106-2. The end plates 106 apply and maintain uniform pressure across the fuel-cell stack 102. A radiator block 104 is also illustrated, which encloses the fuel-cell stack 102. The radiator block 104 comprises channels 306 for the circulation of coolant. It also acts as a supporting structure for the fuel-cell stack assembly 100. The radiator block 104 further comprises a plurality of mounting pillars 304 that offer this support. In an embodiment of this disclosure, the number of mounting pillars 304 is six, disposed at the four corners and one each in the middle of sides W and Y.
[0072] Referring to FIG. 3B, where the fuel-cell stack 102 and radiator block 104 are illustrated in greater detail, the radiator block 104 encases the fuel-cell stack 102. The radiator block 104 comprising channels 306 disposed on its walls that are heat exchangers through which the hot coolant flows and loses heat by heat exchange with ambient. In an embodiment of the present disclosure, the radiator channels 306 can be arranged in a form that maximises the surface area available for heat exchange. The radiator block 104 serves a secondary and complimentary function of acting as a support structure for the fuel-cell stack assembly 100, on which the end plates 106 are mounted. In order to provide this support, a plurality of mounting pillars 304 are distributed through the structure of the radiator block 104. In accordance to an embodiment of the present disclosure, six number of mounting pillars 304 are present, four at the corners and two along the centre of sides W and Y. The fuel-cell stack 102 is encased within the radiator block 104. The fuel-cell stack 102 comprises numerous fuel-cells stacked one over another and connected in series to obtain a higher cumulative voltage. The fuel-cell stack 102 is disposed of numerous electrodes-anode and cathode, separated by membrane electrode assemblies (MEA) that together constitute a fuel-cell. This fuel-cell assembly can further be augmented by the presence of bipolar plates and gaskets which serve to support the fuel-cell and also supply the reaction gases and coolant. The fuel-cell stack 102 also comprises a plurality of ports for the inlet of hydrogen, oxygen and coolant, and a plurality of ports for the outlet of the same.
[0073] Shown in FIG. 3B are the inlets and outlets for coolant in the radiator block 104 and the fuel-cell stack 102. The coolant enters the fuel-cell stack through port 112-1. The coolant, say, cooling water, passes through the common passage and enters individual cooling plates 202. It passes through the channels on the cooling plate, exchanging heat, and exits the cooling plate 202 into the common outlet passage. From this outlet passage, the heated coolant exits the fuel-cell stack 102 through outlet 112-2. The heated coolant is then fed into the radiator block at inlet 302-1. The hot coolant passes along the heat exchangers on the walls of the radiator block 104, losing heat along the way. The coolant then exits the radiator block 104 at the outlet 302-2, from whence, it is fed into the fuel-cell stack 102 for re-circulation. In one embodiment, a pump 308 is used to feed the coolant into the inlet 112-1 of the fuel-cell stack 102.
[0074] FIG. 4A illustrates a fuel-cell stack assembly 100, along with the proposed radiator block 104 encasing the fuel-cell stack 102. The fuel-cell stack 102 and the radiator bock 104 are held by a clamping arrangement 108 in between the end plates 106. A section B-B is indicated, which will be further described in the following figures. FIG. 4B illustrated the cross-section B-B of the fuel-cell stack assembly 100 including the proposed radiator block 104 encasing the fuel-cell stack 102. The end plates 106 are coupled onto the radiator block 104 by bolts. The mounting pillars 304 are located at the corners and also one at the middle of side Y. The radiator channels 306 traverse the sides of the radiator block 104 vertically, between the end plates 106. The bottom and top junctions between the radiator channels 306 and end plates 106 is shown in greater detail in FIGs. 4C and 4D respectively.
[0075] As illustrated in FIGs. 4C and 4D, a channel is created in the end plates 106, at the junction of the end plates 106 and the radiator channels 306. In the proposed radiator block 104, the radiator channels 306 are arranged in a serpentine layout in order that a maximum surface area will be available to the coolant for heat exchange. Once the coolant traverses a channel, it then flows into the adjacent channel and continue its traverse, but in the opposite direction. In order to facilitate the flow of coolant from one channel to the next, a channel is created at the junction where the radiator channel 306 meets the end plate 106. The coolant then moves through the end plate 106 to flow from one radiator channel to the next adjacent channel. As the coolant traverses the channels, it exchanges heat with the ambient to cool down. In FIG. 4C, the coolant, through input 302-1, enters the radiator block 104. The coolant travels up vertically until it reaches the top end plate 106-1 andflows into the adjacent radiator channel through the end plate 106-1 and makes its way down vertically until it reaches the bottom end plate 106-2, as illustrated in FIG 4D. This flow continues until the coolant exits the radiator block 104 through the outlet 302-2.
[0076] In another embodiment of the present disclosure, a stamped plate is used instead of a cooling plate. The stamped plate comprises channels stamped on its surface that allows for the flow of reaction gases as well as coolant. The coolant flows in between the fuel-cells and carries the heat of reaction away through conduction. FIGs. 5A through 7B describe the cooling system for a fuel-cell stack that comprises a stamped plate disposed on either side of the membrane electrode assembly (MEA). The stamped plates are made of a conducting metal and, when assembled, form channels that can be used for the passage of reaction gases and coolant. The stamped plates also act as current collectors for the fuel-cell and carry the current to the common current collector of the fuel-cell stack.
[0077] Referring to FIG. 5A, where an exploded view of a fuel-cell assembly 502 is illustrated, the fuel-cell assembly 502 comprising a membrane electrode assembly (MEA) 508, sandwiched between a pair of gaskets 506 and the proposed stamped plate 504, in accordance with an embodiment of the present disclosure. The plate 504 is stamped so as to feature channels that are used for the flow of coolant and reaction gases. Since coolant and reaction gases flow through an integrated network of channels on the same plate 504, heat exchange occurs more efficiently, and also results in a more compact system. The stamped plate 504 is so stamped that the reaction gases traverse a serpentine path while the coolant follows a straight path. FIG. 5B illustrates an assembled fuel-cell 502 comprising an MEA 508 that is sandwiched between a pair of gaskets 506 and a pair of the proposed stamped plates 504.
[0078] FIGs. 6A and 6B illustrate an assembled fuel-cell 502 and transverse section P-P of the assembled fuel-cell 502 respectively. The assembled fuel-cell 502 comprises a MEA 508 sandwiched between a pair of gaskets 506 and a pair of the proposed stamped plates 504 as anode and cathode plates. FIG. 6C illustrates the cross section of the assembled fuel-cell 502 in greater detail. The pair of stamped plates 504 are shown, which, on either side of the MEA 508, act as the cathode and anode plates. The features stamped on the plate 504, as illustrated, form channels through which coolant as well as reaction gases can flow. The gaskets 506 serve to insulate the fuel-cell and prevent leakage of reaction gases and also prevent contamination of reaction gases.
[0079] Referring now to FIG. 7A, where a sectional view of the fuel-cell stack is illustrated, the section displays a plurality of fuel-cells 502 stacked on top of one another. The fuel-cells are formed by the MEA 508 disposed between a pair of the proposed stamped plates 504. The stamped plates 504 form the cathode plates 710 and anode plates 712 that collect the current from each fuel-cell and carry it to the common current collector of the fuel-cell stack 804. The bipolar plates702 are provided to offer support to the fuel-cell and also to supply the reaction gases and coolant. The bipolar plates 702 are assembled in a way that a gap is created that allows the flow of coolant to the stamped plates 504. FIG. 7B illustrates the flow paths of the reaction gases and the coolant in the sectional view of the fuel-cell stack, in accordance with an embodiment of the present disclosure. The flow path of the coolant 704 is adjacent to the fuel-cells 502 and this ensures that heat is efficiently exchanged between the fuel-cell 502 and the coolant. The flow paths for hydrogen 706 and oxygen 708 are also shown, as they supply the gases to the electrodes. To ensure maximum heat exchange, the hydrogen and oxygen flow paths 706 and 708 respectively, traverse a serpentine path on the stamped plate 504.
[0080] Referring to FIG. 8A, wherein the cooling arrangement employed within the fuel-cell stack 804 is disclosed, in accordance with an embodiment of this disclosure, the cooling arrangement comprising a stamped plate 504 carrying channels for the circulation of a coolant and reaction gases, that is disposed on either side of the MEA 508 in the fuel-cell assembly. The stamped plates 504 act as the cathode plates 710 and anode plates 712 for the fuel-cell and serve to collect and carry the current to the current collector. The stamped plate 504 is a conducting plate that has stamped patterns that, when assembles in a fuel-cell, become channels for the flow of coolant and reaction gases. The reaction gases flow in a serpentine flow path through the stamped plate 504 while the coolant flows straight. The serpentine nature of the reaction gases flow path allows for the maximum surface area for the interaction of the reaction gases and the coolant for maximum heat exchange. The material of the stamped plate 504 can be conducting materials such as, but not limited to, stainless steel, aluminium, graphene etc.
[0081] Referring to FIG. 8B, wherein an exploded view of a fuel-cell stack assembly is illustrated with the radiator block, in accordance with an embodiment of this disclosure. The assembly comprisesa fuel-cell stack 804 that is clamped between a top end plate 808-1 and a bottom end plate 808-2. The end plates apply and maintain uniform pressure across the fuel-cell stack 804. To accomplish this, a clamping arrangement can be employed which can comprise a plurality of components that serve to apply and maintain uniform pressure across the fuel-cell stack 804. A radiator block 104 is also illustrated, which encases the fuel-cell stack 804. The radiator block 104 comprises channels 306 for the circulation of coolant. It also acts as a supporting structure for the fuel-cell stack assembly. It comprises a plurality of mounting pillars 304 that offer this support. In an embodiment of this disclosure, the number of mounting pillars 304 is six, disposed at the four corners and one each in the middle of sides W and Y of the radiator block 104.
[0082] Referring FIG. 8C, wherein the fuel-cell stack 804 is illustrated in greater detail. The fuel-cell stack 804 comprises numerous fuel-cells stacked one over another and connected in series to obtain a higher cumulative voltage. The fuel-cell stack 804 is made up of numerous fuel-cells that comprise a pair of stamped plates 504 which sandwiches the MEA 508. This fuel-cell assembly is further augmented by the presence of bipolar plates 702 and gaskets 506, which serve to support the fuel-cell and also supply the reaction gases and coolant. The fuel-cell stack 804 comprises a plurality of current collectors which tap the potential generated by the fuel-cell stack 804. The fuel-cell stack 804 also comprises a plurality of ports, such as 810-1 and 814-1, for the inlet of hydrogen and oxygen, and a plurality of ports, such as 810-2 and 814-2, for the outlet of the same. In accordance with an embodiment of this disclosure, the ports are located at the bottom of the fuel-cell stack 804.
[0083] The fuel-cell stack 804 is encased by the radiator block 104. The heated coolant exiting from the outlet 812-2 is fed into the radiator block at inlet 302-1. The hot coolant passes along the heat exchangers on the walls of the radiator block 104, losing heat along the way. The coolant then exits the radiator block 104 at the outlet 302-2, from whence, it is fed into inlet 812-1 of the fuel-cell stack 804for re-circulation. In one embodiment of this disclosure, a pump 308 is used to feed the coolant into the inlet 812-1 of the fuel-cell stack 804.
[0084] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the disclosure is determined by the claims that follow. The disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the disclosure when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES
[0085] The present disclosure provides a fuel-cell stack with a cooling arrangement.
[0086] The present disclosure provides a cooling arrangement for recirculating the coolant without a need for an external cooling apparatus.
[0087] The present disclosure provides a fuel-cell design with stamped passages to circulate reaction gases and coolant through the fuel-cell.
[0088] The present disclosure provides a radiator that is integrated into a mounting arrangement of the fuel cell stack assembly.
[0089] The present disclosure provides a radiator block that acts as a support and housing to the fuel cell stack assembly.
[0090] The present disclosure provides a fuel-cell stack that is compact.
[0091] The present disclosure provides a radiator block that does not occupy additional space.
,CLAIMS:

1. A fuel-cell stack assembly, said assembly comprising:
a fuel-cell stack comprising:
a plurality of fuel-cells stacked in series;
one or more inlets for entry of a coolant to absorb heat from the plurality of fuel-cells; and
one or more outlets for exit of the coolant; and
a radiator block configured to house the fuel-cell stack, said radiator block is having a plurality of channels configured on walls of the radiator block such that one end of the plurality of channels is coupled to the one or more outlets of the fuel-cell stack and other end of the plurality of channels is coupled to the one or more inlets of the fuel-cell stack,
wherein the coolant flows from the one or more outlets of the fuel-cell stack to the one or more inlets of the fuel-cell stack by passing through the plurality of channels enables cooling of the coolant by heat exchange with an ambient atmosphere.
2. The fuel-cell stack assembly as claimed in claim 1, wherein the plurality of fuel-cells are stacked vertically and in the same orientation.
3. The fuel-cell stack assembly as claimed in claim 1, wherein the radiator block comprises a plurality of pillars configured as mounting support for the fuel-cell stack.
4. The fuel-cell stack assembly as claimed in claim 1, wherein the plurality of channels configured on the radiator block are arranged in a serpentine configuration.
5. The fuel-cell stack assembly as claimed in claim 1, wherein the fuel-cell stack comprises at least two current collectors to extract the current produced by the plurality of fuel-cells.
6. The fuel-cell stack assembly as claimed in claim 1, wherein the fuel-cell stack comprises one or more inlets and corresponding one or more outlets configured for flow of hydrogen and any of or a combination of air and oxygen for an anode and a cathode respectively of each of the plurality of fuel-cells.
7. The fuel-cell stack assembly as claimed in claim 1, wherein the fuel-cell stack comprises:
a plurality of fuel-cells stacked in series; and
a plurality of cooling plates disposed at regular intervals in between the plurality of fuel-cells, wherein each of the plurality of cooling plates comprises one or more channels, such that one end of the one or more channels is configured to receive coolant from the one or more inlets of the fuel-cell stack and the other end of the one or more channels is configured to discharge the coolant to the one or more outlets of the fuel-cell stack, and
wherein the flow of the coolant on each of the plurality of cooling plates enables cooling of at least one thermally coupled of the plurality of fuel-cells.
8. The fuel-cell stack assembly as claimed in claim 7, wherein the one or more channels on each of the plurality of cooling plates are arranged in a serpentine configuration.
9. The fuel-cell stack assembly as claimed in claim 1, wherein each of the plurality of fuel-cells comprises:
two stamped plates configured to be electrodes, their flat surfaces facing each other, with at least one stamped plate configured to have a non-uniform topography such that a plurality of passages are formed by the arrangement of the two stamped plates,
wherein one or more of the plurality of passages are adapted to allow flow of the coolant to enable cooling of the fuel-cell.