Reoperable fuel cell stack

Abstract

The present invention provides a reoperable fuel cell stack in which a first separator and a second separator forming one fuel cell are bonded to a membrane electrode assembly (MEA) by a hot melt adhesive, the first separator being bonded to a third separator of another fuel cell by a first UV adhesive film, and the second separator being bonded to a third separator of another fuel cell by a second UV adhesive film. The second separator is bonded to the fourth separator of another fuel cell by a second UV adhesive film such that, among the plurality of fuel cells, a defective specific fuel cell is readily selectively separated from the fuel cell stack and readily replaced by a new or replaced fuel cell.

Description

Technical Field

[0001] The present invention relates to a reworkable fuel cell stack. Background Art

[0002] A fuel cell stack configured to generate electricity installed in a fuel cell vehicle or the like is manufactured into a structure in which tens to hundreds of fuel cells, each of which includes a membrane electrode assembly (MEA) and two or more separators, are stacked.

[0003] The MEA includes a polymer electrolyte membrane, and a cathode and an anode applied on both surfaces of the electrolyte membrane to react with hydrogen and oxygen, respectively.

[0004] In addition, a gas diffusion layer (GDL), a gasket, and the like are stacked on the outside of the cathode and the anode, and a separator is stacked on the outside of the GDL.

[0005] When assembling a fuel cell stack, in the event that a defective MEA or a defective separator is included in a specific fuel cell, or a specific fuel cell defect or failure occurs during driving of the fuel cell stack, the fuel cell stack may need to be disassembled for repair.

[0006] However, when a fuel cell stack including a defective MEA or a defective separator is disassembled for repair, problems may arise such as the size of the MEA changing due to shrinkage caused by moisture evaporation as the MEA is exposed to the air, or the MEA being damaged due to external contaminants mixing into the MEA during the replacement of the fuel cell.

[0007] In addition, although the defective MEA is replaced with a new MEA, performance deviation may occur between the individual fuel cells of the fuel cell stack due to a difference in activity level between the defective MEA before replacement and the new MEA after replacement.

[0008] Furthermore, the separators of the fuel cell stack are formed of a thin metal material and thus are easily deformed by impact when the fuel cell stack is disassembled, and thus it is difficult to completely separate the separators from the fuel cell stack without deformation to reuse the separators.

[0009] Since the separator of the fuel cell stack is bonded to other components (eg, gaskets, etc.), in order to easily peel the separator from the fuel cell stack, the separator must be heated.

[0010] For example, the separator may be separated from the fuel cell stack by various methods, such as by placing the fuel cell stack in a chamber in a high temperature state, by applying hot air directly to the separator, by applying heat to the separator using a soldering iron, and the like.

[0011] However, in this case, in order to separate the separator from the fuel cell stack, an operation of placing the fuel cell stack in a chamber in a high temperature state, an operation of directly applying hot air to the separator, etc. are required, whereby the separator peeling feasibility is greatly reduced.

[0012] The above information disclosed in this Background section is only for enhancing understanding of the background of the invention and therefore it may contain information that does not constitute known prior art. Summary of the invention

[0013] The present invention relates to a re-operable fuel cell stack. More particularly, the present invention relates to such a re-operable fuel cell stack in which a specific fuel cell among a plurality of fuel cells can be easily and selectively separated therefrom so that a defective fuel cell can be easily replaced.

[0014] An embodiment of the present invention strives to solve the above-mentioned problems associated with the prior art, and an advantage of an embodiment of the present invention is to provide a reworkable fuel cell stack, wherein a first separator and a second separator forming one fuel cell can be bonded to a membrane electrode assembly (MEA) by a hot melt adhesive, the first separator can be bonded to a third separator forming another fuel cell by a UV adhesive film, and the second separator can be bonded to a fourth separator forming yet another fuel cell by a UV adhesive film, so that among a plurality of fuel cells, a defective specific fuel cell can be easily and selectively separated from the fuel cell stack and can be easily replaced with a new fuel cell.

[0015] In an embodiment of the present invention, a reworkable fuel cell stack includes: a fuel cell comprising a membrane electrode assembly, and a first separator and a second separator stacked on both surfaces of the membrane electrode assembly; at least one subgasket fixed to the periphery of the membrane electrode assembly; a hot melt adhesive applied to both surfaces of the at least one subgasket to bond to the first separator and the inner surfaces of the second separator, and a UV adhesive film attached to the outer surface of the first separator to bond to a third separator of another fuel cell and attached to the outer surface of the second separator to bond to a fourth separator of yet another fuel cell.

[0016] In an embodiment, when the first gasket is fixed to the inner surface of the first separator and the second gasket is fixed to the inner surface of the second separator, the hot melt adhesive applied to both surfaces of at least one subgasket may be bonded to the first gasket and the second gasket, respectively.

[0017] In an embodiment, at least one subgasket may be provided to be configured so that a hot melt adhesive is applied to both surfaces thereof and may be fixed to the cathode of the membrane electrode assembly and the periphery of the gas diffusion layer stacked outside the cathode.

[0018] In an embodiment, when the first gasket is bonded to the hot melt adhesive applied to one surface of at least one subgasket and the second gasket is bonded to the hot melt adhesive applied to the remaining surface of at least one subgasket, one surface of the electrolyte membrane at both ends of the membrane electrode assembly may be bonded to the hot melt adhesive applied to the remaining surface of at least one subgasket.

[0019] In an embodiment, at least one subgasket may include: a first subgasket configured to have a hot melt adhesive applied to its two surfaces and fixed to the cathode of the membrane electrode assembly and the periphery of the gas diffusion layer stacked outside the cathode; and a second subgasket configured to have a hot melt adhesive applied to its two surfaces and fixed to the anode of the membrane electrode assembly and the periphery of the gas diffusion layer stacked outside the anode.

[0020] In an embodiment, when the first separator is directly bonded to the hot melt adhesive applied to the outer surface of the first subgasket and the second separator is directly bonded to the hot melt adhesive applied to the outer surface of the second subgasket, one surface and the remaining surfaces of the electrolyte membrane at both ends of the membrane electrode assembly may be bonded to the hot melt adhesive applied to the inner surface of the first subgasket and the inner surface of the second subgasket.

[0021] In an embodiment, the hot melt adhesive may be a polyolefin-based adhesive, a styrene butadiene rubber-based adhesive, a butyl rubber, or any combination thereof having a dispersion force of 20 mN / m or more and a polar force of 0.01-1.91 mN / m to bond to at least one subgasket formed of polyethylene naphthalate (PEN), a first and second gasket formed of ethylene propylene diene monomer rubber (EPDM), and each of the electrolyte membranes of the membrane electrode assembly.

[0022] In an embodiment, the hot melt adhesive may be a polyolefin-based adhesive having a softening point of 67° C. to 110° C., a styrene butadiene rubber-based adhesive, butyl rubber, or any combination thereof.

[0023] In an embodiment, the UV adhesive film may include a film substrate formed of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), an olefin-based material, or any combination thereof, and an adhesive applied to both surfaces of the film substrate.

[0024] In an embodiment, the adhesive applied to both surfaces of the film substrate may be an acrylic material, a multifunctional acrylic urethane, an epoxy acryl, or any combination thereof.

[0025] In an embodiment, the adhesive applied to both surfaces of the film substrate may include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO) as a photoinitiator configured to generate free radicals when the adhesive is irradiated with UV light.

[0026] In embodiments, the adhesive applied to both surfaces of the film substrate may include a UV absorber or a light stabilizer for adjusting sensitivity to UV light.

[0027] In an embodiment, in addition to the UV adhesive film, a third gasket may be placed between the first separator and the third separator and between the second separator and the fourth separator.

[0028] In an embodiment, heat generated by UV light radiated to the UV adhesive film by the UV light irradiation device may be blocked by the first and second spacers and the first and second gaskets to avoid being conducted to the hot melt adhesive.

[0029] In an embodiment, the amount of UV light radiated to the UV adhesive film by the UV light irradiation device can be adjusted to be less than a specified level for a long period of time over a specified time, so as to prevent heat generated by the UV light radiated to the UV adhesive film from being transferred to the hot melt adhesive.

[0030] In an embodiment, the bonding area of ​​the UV adhesive film may be reduced to be smaller than the application area of ​​the hot melt adhesive so that the heat capacity generated by UV light radiated to the UV adhesive film is set to a level that cannot melt the hot melt adhesive.

[0031] Other aspects and preferred embodiments of the invention are discussed below.

[0032] The above and other features of the invention are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and other features of the present invention will now be described in detail with reference to example embodiments of the invention shown in the accompanying drawings, which are given hereinafter by way of illustration, without limiting the present invention thereby, and in which:

[0034] Figure 1 is a cross-sectional view of a re-operable fuel cell stack according to an embodiment of the present invention;

[0035] Figures 2 to 7 A cross-sectional view sequentially showing a process of replacing a fuel cell to be replaced of a fuel cell stack according to an embodiment of the present invention with a new fuel cell;

[0036] Figures 8 to 12 A cross-sectional view sequentially showing a process of replacing an MEA of a fuel cell to be replaced of a fuel cell stack according to an embodiment of the present invention with a new MEA;

[0037] Fig.13 is a cross-sectional view of a re-operable fuel cell stack according to an embodiment of the present invention;

[0038] Fig.14 is a cross-sectional view of a re-operable fuel cell stack according to an embodiment of the present invention;

[0039] Fig.15 is a graph showing the results of evaluating the adhesive force of a hot melt adhesive used in a reworkable fuel cell stack according to an embodiment of the present invention; and

[0040] Fig.16 is a graph showing the results of peel force measurements of hot melt adhesives used in a reworkable fuel cell stack according to an embodiment of the present invention.

[0041] It should be understood that the drawings are not necessarily drawn to scale, and that they present somewhat simplified representations of various features illustrating embodiments of the present invention. The specific design features of the embodiments of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes, may be determined in part by the specific intended application and use environment.

[0042] In the drawings, reference numbers may refer to the same or equivalent parts of embodiments of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0043] The specific structures or functions in the embodiments of the present invention described in the following description are described as examples, and the present invention can be embodied in a variety of alternative forms. In addition, it is understood that the present invention should not be interpreted as being limited to the embodiments described herein, and the embodiments of the present invention are provided only to fully disclose the present invention and to provide an understanding of modifications, equivalents or alternatives that fall within the scope and technical scope of the present invention.

[0044] In the following description of the embodiments, terms such as "first" and "second" may be used to describe various elements, and these elements should not be limited by these terms. These terms may be used to distinguish one element from other elements. For example, without departing from the scope of the present invention, the first element described below may be referred to as the second element, and similarly, the second element described below may be referred to as the first element.

[0045] When an element or layer is referred to as being "connected to" or "coupled to" another element or layer, it may be directly connected or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element or layer is referred to as being "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements may be interpreted in a similar manner, such as "between" and "directly between", "adjacent" and "directly adjacent", etc.

[0046] Throughout the drawings, the same reference numerals are used as much as possible to represent the same or similar parts. The terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular form may also be intended to include the plural form. The terms "comprise", "include" and "have" are open and therefore specify the presence of the features, integers, operations, elements, components or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, operations, elements, components or combinations thereof.

[0047] Hereinafter reference will be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below.

[0048] Figure 1 is a cross-sectional view of a reworkable fuel cell stack according to an embodiment of the present invention, and reference numeral 100 denotes a membrane electrode assembly (MEA).

[0049] The MEA 100 may include a polymer electrolyte membrane 101 , a cathode 102 and an anode 103 applied to both surfaces of the electrolyte membrane 101 and configured to react with hydrogen and oxygen, and a gas diffusion layer 104 may be attached to outer surfaces of the cathode 102 and the anode 103 .

[0050] In addition, the first separator 110 and the second separator 120 may be stacked on both surfaces of the MEA 100 .

[0051] The first separator 110 may be stacked on the outer side of the gas diffusion layer 104 attached to the cathode 102 of the MEA 100 , and the second separator 120 may be stacked on the outer side of the gas diffusion layer 104 attached to the anode 103 of the MEA 100 .

[0052] Therefore, the MEA 100, the first separator 110, and the second separator 120 may form one fuel cell.

[0053] A fuel cell stack can be manufactured into a structure of dozens to hundreds of fuel cells stacked, each fuel cell including a membrane electrode assembly (MEA) and two or more separators, and thus, Figure 1As shown, a third separator 130 of another fuel cell may be stacked on an outer surface of the first separator 110 , and a fourth separator 140 of still another fuel cell may be stacked on an outer surface of the second separator 120 .

[0054] The gap between the inner surface of the first separator 110 and the MEA and the gap between the inner surface of the second separator 120 and the MEA 100 may be set as reaction surfaces for electrochemical reactions such as a redox reaction between hydrogen and oxygen occurring in the MEA 100 .

[0055] Specifically, the sub-gasket 150 is constructed so that the hot melt adhesive 10 is applied to its two surfaces, the sub-gasket 150 can be fixed to the periphery of the MEA 100 located between the first separator 110 and the second separator 120, and the first gasket 161 can be fixed to the edge of the inner surface of the first separator 110, and the second gasket 162 can be fixed to the edge of the inner surface of the second separator 120.

[0056] The subgasket 150 , the first gasket 161 , and the second gasket 162 may serve to hermetically and watertightly seal reaction surfaces provided between the inner surface of the first separator 110 and the MEA 100 , and between the inner surface of the second separator 120 and the MEA 100 .

[0057] Specifically, the subgasket 150 may be configured such that the hot melt adhesive 10 is applied to both surfaces thereof, and may be located at the periphery of the cathode 102 of the MEA 100 and the gas diffusion layer 104 stacked outside the cathode 102 .

[0058] The first gasket 161 may be attached to the hot melt adhesive 10 applied to one surface of the subgasket 150, the second gasket 162 may be attached to the hot melt adhesive 10 applied to the other surface of the subgasket 150, and one surface of both ends of the electrolyte membrane 101 of the MEA 100 may be bonded to the hot melt adhesive 10 applied to the other surface of the subgasket 150.

[0059] The hot melt adhesive 10 may be a material that can be bonded to the subgasket 150 formed of polyethylene naphthalate (PEN), the first gasket 161 and the second gasket 162 formed of ethylene propylene diene monomer (EPDM), and the electrolyte membrane 101 formed of Nafion.

[0060] For example, assuming that the dispersion force (a type of surface energy) of the first gasket 161 and the second gasket 162 formed of EPDM may be 23.55 mN / m and the polar force may be 0.01 mN / m, and the dispersion force of the sub-gasket 150 formed of PEN may be 44.51 mN / m and the polar force may be 1.91 mN / m, the hot melt adhesive 10 may use a material having a dispersion force of more than 20 mN / m and a polar force of 0.01-1.91 mN / m, preferably 0.5-1.7 mN / m. Although the electrolyte membrane 101 can be well attached to the hot melt adhesive 10, when the polar force of the hot melt adhesive 10 is too high, that is, higher than the range of 0.01-1.91 mN / m, the hot melt adhesive 10 will not be attached to the first gasket 161 and the second gasket 162 formed of EPDM, and when the polar force of the hot melt adhesive 10 is too low, that is, lower than the range of 0.01-1.91 mN / m, it will not be attached to the sub-gasket 150 formed of PEN.

[0061] In addition, the hot melt adhesive 10 can use a material with a softening point of 67°C-110°C, and the hot melt adhesive 10 can continuously exhibit adhesion to the subgasket 150, the first gasket 161 and the second gasket 162, the electrolyte membrane 101, etc. within a temperature range of 60°C-70°C during the fuel cell stack activation operation, but depending on the heating of the hot melt adhesive 10, it can exhibit reduced adhesion at the softening point (for example, above 90°C) to easily separate the MEA of a specific fuel cell from the fuel cell stack.

[0062] For example, polyolefin-based adhesives, styrene butadiene rubber-based adhesives, butyl rubber, etc., which have a dispersion force of more than 20 mN / m, a polar force of 0.01-1.91 mN / m, preferably 0.5-1.7 mN / m, and a softening point of 67°C-110°C, can be used as the hot melt adhesive 10.

[0063] The adhesive force of the hot melt adhesive 10 increases rapidly when the softening point is above 60°C. Fig.15 As shown in FIG. 1 (the figure shows a graph showing the adhesive strength evaluation results of the hot melt adhesive 10), the adhesive strength of the hot melt adhesive 10 converges to zero (0) when the temperature is above 80° C., as shown in FIG. Fig.16 (The figure shows a graph showing the peel force measurement results of the hot melt adhesive 10).

[0064] Therefore, for example, by heating the hot melt adhesive 10 to a temperature of 80° C. or higher in a hot air chamber at a temperature of 90° C. or higher to reduce the adhesive force of the hot melt adhesive 10 , the MEA of a specific fuel cell can be easily separated from the fuel cell stack.

[0065] In particular, the first separator 110 and the third separator 130 may be bonded by an ultraviolet (UV) adhesive film 20 , and the second separator 120 and the fourth separator 140 may be bonded by the UV adhesive film 20 .

[0066] More specifically, the first separator 110 and the third separator 130 can be bonded by the UV adhesive film 20 by bonding the edge of the outer surface of the first separator 110 of one fuel cell and the edge of the outer surface of the third separator 130 of another fuel cell to each other by the UV adhesive film 20 inserted therebetween, and the second separator 120 and the fourth separator 140 can be bonded by bonding the edge of the outer surface of the second separator 120 of one fuel cell and the edge of the outer surface of the fourth separator 140 of another fuel cell to each other by the UV adhesive film 20 inserted therebetween, thereby being bonded by the UV adhesive film 20.

[0067] The gap between the first separator 110 and the third separator 130 and the gap between the second separator 120 and the fourth separator 140 may be provided as a cooling surface, which functions as a coolant passage and dissipates heat generated from the reaction surface.

[0068] The UV adhesive film 20 may function as a cooling surface that hermetically and watertightly seals a gap provided as between the first separator 110 and the third separator 130 and between the second separator 120 and the fourth separator 140 , and loses adhesive force as it is cured using UV.

[0069] In particular, Fig.13 As described, according to an embodiment of the present invention, in addition to the UV adhesive film 20, a third gasket 163 formed of ethylene propylene diene monomer can be used to enhance the airtightness and watertightness of the cooling surface (set as the gap between the first partition 110 and the third partition 130 and the gap between the second partition 120 and the fourth partition 140).

[0070] like Fig.13 As shown, the first partition 110 and the third partition 130 can be bonded by the UV adhesive film 20 in a state where the third gasket 163 is located between the first partition 110 and the third partition 130, and the second partition 120 and the fourth partition 140 can be bonded by the UV adhesive film 20 in a state where the third gasket 163 is located between the second partition 120 and the fourth partition 140.

[0071] The UV adhesive film 20 may include a film substrate and an adhesive applied to both surfaces of the film substrate and whose adhesive force rapidly decreases due to curing when ultraviolet light is applied thereto. One selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and olefin-based materials may be used as the film substrate, and, for example, acrylic materials, multifunctional acrylic polyurethane, epoxy acrylic resin, etc. may be used as the adhesive applied to both surfaces of the film substrate.

[0072] In addition, the adhesive applied to the film substrate may include: a photoinitiator (which generates free radicals when the adhesive is irradiated with UV light), such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), and a UV absorber (e.g., benzophenone) or a light stabilizer (e.g., 2,2,6,6-tetramethylpiperidine) to adjust the sensitivity to UV light, so that the adhesive applied to the film substrate can have soft properties before being irradiated with UV light and can have hard properties after being irradiated with UV light.

[0073] The UV light irradiation device can be configured to irradiate the UV adhesive film 20 with UV light in a wavelength band of 200nm to 405nm, and a short-wavelength lamp using an LED, a high-pressure mercury lamp, a halogen lamp, etc. can be used, preferably an LED laser light source configured to radiate light with a wavelength of 365nm.

[0074] In addition, the UV light irradiation device may radiate UV light having a wavelength of 365 nm to the UV adhesive film 20 so that the accumulated light amount is 700 mJ / cm 2 , to prevent heat from being transferred to the hot melt adhesive 10 and thereby prevent the adhesive force of the hot melt adhesive 10 from being reduced.

[0075] Even if the UV light irradiation device can radiate UV light to the UV adhesive film 20 so that the accumulated light amount is 700 mJ / cm 2 As above, but in one embodiment, heat should penetrate the first and second separators 110, 120 formed of SUS and the first and second gaskets formed of EPDM to be conducted to the hot melt adhesive 10, so the heat causing the reduction of the adhesive force may not be easily transferred to the hot melt adhesive 10.

[0076] In one embodiment, even if the UV light irradiation device can radiate UV light to the UV adhesive film 20 so that the cumulative light amount is 700 mJ / cm 2 As above, however, the first and second separators 110 , 120 formed of SUS and the first and second gaskets formed of EPDM block the heat generated by the UV light from being conducted to the hot melt adhesive 10 .

[0077] For example, in one embodiment, because the thermal conductivity of EPDM as the material of the first gasket 161 and the second gasket 162 is 0.25 W / m·K, and the thermal conductivity of stainless steel (SUS) as the material of the first separator 110 and the second separator 120 is 16.2 W / m·K (in the case of SUS 307), the heat generated when the UV adhesive film 20 is irradiated with UV light is not transferred to the hot melt adhesive 10 through the first gasket 161 and the second gasket 162, and even if the heat is transferred to the hot melt adhesive 10 through the first separator 110 and the second separator 120 formed of stainless steel, the transferred heat is not sufficient to melt the hot melt adhesive 10.

[0078] In addition, in one embodiment, when the amount of UV light radiated to the UV adhesive film 20 by the UV light irradiation device increases to above a specified level within a short time period shorter than a specified time, the heat transferred to the hot melt adhesive 10 can instantly rise to a temperature of 100°C-160°C, but when the amount of UV light radiated to the UV adhesive film 20 by the UV light irradiation device is adjusted to be less than a specified level within a long time period longer than a specified time, the heat that causes a decrease in the adhesive force is not easily transferred to the hot melt adhesive 10.

[0079] Alternatively, by reducing the bonding area of ​​the UV adhesive film 20 compared to the application area of ​​the hot melt adhesive 10 , although the UV irradiation device radiates UV light to the UV adhesive film 20 , heat that causes a decrease in adhesive force is not easily transferred to the hot melt adhesive 10 .

[0080] The bonding area of ​​the UV adhesive film 20 may be reduced to be smaller than the application area of ​​the hot melt adhesive 10 so that the heat capacity generated by UV light radiated to the UV adhesive film 20 is set to a level that cannot melt the hot melt adhesive 10 .

[0081] By reducing the bonding area of ​​the UV adhesive film 20 compared to the application area of ​​the hot melt adhesive 10, the heat capacity generated by the UV light radiated to the UV adhesive film 20 by the UV light irradiation device can be set only to a level at which the adhesive force of the UV adhesive film 20 is lost due to curing, but not to a level at which the hot melt adhesive 10 is completely melted, so that, for example, although the UV light is radiated to the UV adhesive film 20, the adhesive force of the hot melt adhesive 10 is not reduced or lost.

[0082] A process of replacing a fuel cell of a fuel cell stack according to an embodiment of the present invention to be replaced with a new fuel cell will be described in order below.

[0083] Figures 2 to 7 sectional views sequentially showing a process of replacing a fuel cell of a fuel cell stack according to an embodiment of the present invention to be replaced with a new fuel cell.

[0084] When assembling a fuel cell stack, in the case where a defective MEA or a defective separator is included in a specific fuel cell, or in the case where a defect or failure of a specific fuel cell occurs during driving of the fuel cell stack, the specific fuel cell may be set as a fuel cell to be replaced, such as Figure 2 As shown, the fuel cell to be replaced can be easily replaced with a new fuel cell using, for example, an embodiment.

[0085] After the housing 170 configured to protect the fuel cell stack is disassembled, the ultraviolet light irradiation device 180 may radiate UV light to the UV adhesive film 20 configured to bond the first separator 110 and the third separator 130 to each other and the UV adhesive film 20 configured to bond the second separator 120 and the fourth separator 140 to each other, as shown in FIG. Figure 3 shown.

[0086] Therefore, as curing of the UV adhesive film 20 by irradiation with UV light proceeds, the UV adhesive film 20 may lose adhesive force.

[0087] Then, if Figure 4 As shown, the third separator 130 of another fuel cell can be easily separated from the first separator 110, and the fourth separator 140 of yet another fuel cell can be easily separated from the second separator 120, so that the fuel cell to be replaced including the first separator 110 and the second separator 120 can be easily separated from the fuel cell stack without any damage.

[0088] Then, if Figure 5 As shown, a new or replacement fuel cell of identical construction to the fuel cell to be replaced, ie, a non-defective fuel cell, may be provided and inserted in place of the fuel cell to be replaced.

[0089] Then, if Figure 6 As shown, the entire fuel cell including the new fuel cell can be fastened by applying a specified surface pressure thereto, and can thus be reassembled into a fuel cell stack.

[0090] The first separator 110 of the new fuel cell and the third separator 130 of another fuel cell can be bonded to each other by a UV adhesive film 20 pre-applied to the first separator 110, and the second separator 120 of the new fuel cell and the fourth separator 140 of another fuel cell can be bonded to each other by a UV adhesive film 20 pre-applied to the second separator 120.

[0091] Finally, the reassembled fuel cell stack may be packaged into the housing 170 again.

[0092] The UV adhesive film 20 and the like may be protected by the housing 170 , whereby the UV adhesive film 20 and the like may be protected from external heat or solar heat to prevent curing.

[0093] Therefore, in the event that a defective MEA or a defective separator is included in a specific fuel cell forming a fuel cell stack, or in the event that a specific fuel cell defect or failure occurs during driving of the fuel cell stack, the specific fuel cell (which is the fuel cell to be replaced) can be easily separated from the fuel cell stack without any damage for reuse, and can be easily replaced with a new fuel cell.

[0094] Hereinafter, a process of replacing the MEA of the fuel cell of the fuel cell stack according to the embodiment of the present invention to be replaced with a new fuel cell MEA will be described in order.

[0095] Figures 8 to 12 sectional views sequentially showing a process of replacing an MEA of a fuel cell of a fuel cell stack according to an embodiment of the present invention to be replaced with a new or replacement MEA.

[0096] In the event that a membrane electrode assembly (MEA) included in a fuel cell to be replaced is defective, the MEA can be easily replaced with a non-defective new or replacement MEA after the fuel cell to be replaced is separated from the fuel cell stack.

[0097] For this reason, Figure 8 As shown, the fuel cell to be replaced separated from the fuel cell stack may be heated to a specified temperature (eg, above 90° C.).

[0098] Thus, the hot melt adhesive 10 included in the fuel cell to be replaced can be heated to a softening point (e.g., above 90° C.), whereby the hot melt adhesive 10 can lose almost all of its adhesive force, and the first gasket 161 and the second gasket 162 included in the fuel cell to be replaced can be easily separated from the hot melt adhesive 10 applied to both surfaces of the subgasket 150.

[0099] Since the fuel cell to be replaced is in a state where the first gasket 161 fixed to the first separator 110 and the second gasket 162 fixed to the second separator 120 can be easily separated from the hot melt adhesive 10, the first separator 110 and the second separator 120 can be easily removed from the MEA 100 included in the fuel cell to be replaced, whereby the MEA 100 to be replaced can be separated from the first separator 110 and the second separator 120, as shown in FIG. Fig. 9 shown.

[0100] Afterwards, if Fig.10As shown, a new or replacement MEA 100 having the same configuration as the MEA 100 to be replaced, ie, a non-defective MEA 100 , may be provided and may be inserted into position between the first separator 110 and the second separator 120 .

[0101] Afterwards, if Fig.11 As shown, fastening may be achieved by applying pressure to the first separator 110, the new MEA 100, and the second separator 120, resulting in a new fuel cell, and a known activation process may be performed to smoothly operate the new or replaced fuel cell.

[0102] During the operation of activating a new fuel cell, the hot melt adhesive 10 included in a new or replaced fuel cell may exhibit adhesion relative to the subgasket 150, the first gasket 161 and the second gasket 162, the electrolyte membrane 101, etc. within a temperature range of 60°C to 70°C.

[0103] Finally, if Fig.12 As shown, a UV adhesive film 20 for bonding the first separator 110 and the second separator 120 to separators of other fuel cells is attached to edges of respective outer surfaces of the first separator 110 and the second separator 120 .

[0104] Therefore, in the event that a membrane electrode assembly (MEA) included in a fuel cell to be replaced is defective, the MEA can be easily replaced with a non-defective new or replacement MEA after the fuel cell to be replaced is separated from the fuel cell stack.

[0105] Fig.14 is a cross-sectional view of a reoperable fuel cell stack according to an embodiment of the present invention.

[0106] The reworkable fuel cell stack according to an embodiment of the present invention may have the same construction as the reworkable fuel cell stack according to the embodiment described above, and may be characterized in that the first separator 110 and the second separator 120 are directly bonded to the hot melt adhesive 10 in a state where the first gasket 161 and the second gasket 162 are omitted.

[0107] Two or more sub-gaskets 151, 152 (which are constructed so that the hot melt adhesive 10 is applied to both surfaces thereof) may be provided around the MEA 100 so that the hot melt adhesive 10 may be directly attached to the inner surfaces of the first separator 110 and the second separator 120, thereby reducing the number of parts due to the omission of the first gasket 161 and the second gasket 162.

[0108] like Fig.14As shown, a first subgasket 151 and a second subgasket 152 (which are constructed so that the hot melt adhesive 10 is applied to its two surfaces) are provided, and the first subgasket 151 is located at the periphery of the cathode 102 of the MEA 100 and the gas diffusion layer 104 stacked on the outside of the cathode 102, and the second subgasket 152 can be located at the periphery of the anode 103 of the MEA 100 and the gas diffusion layer 104 stacked on the outside of the anode 103.

[0109] Subsequently, the first separator 110 and the second separator 120 may be stacked on the gas diffusion layer 104 stacked on the outer side of the cathode 102 and on the gas diffusion layer 104 stacked on the outer side of the anode 103 .

[0110] Thus, the first separator 110 can be directly bonded to the hot melt adhesive 10 applied to the outer surface of the first subgasket 151, the second separator 120 can be directly bonded to the hot melt adhesive 10 applied to the outer surface of the second subgasket 152, and the two surfaces of the end portions of the electrolyte membrane 101 of MEA100 can be bonded to the hot melt adhesive 10 applied to the inner surfaces of the first and second subgaskets 151 and 152.

[0111] Therefore, in a state where the first gasket 161 and the second gasket 162 are omitted, the first and second subgaskets 151 and 152 can be used to hermetically and watertightly seal the reaction surfaces provided between the inner surface of the first separator 110 and the MEA 100 and between the inner surface of the second separator 120 and the MEA 100.

[0112] As is apparent from the above description, the embodiments of the present invention can provide the following effects.

[0113] First, the first separator and the second separator forming one fuel cell can be bonded to the membrane electrode assembly (MEA) by a hot melt adhesive, the first separator can be bonded to the third separator forming another fuel cell by a UV adhesive film, and the second separator can be bonded to the fourth separator forming yet another fuel cell by a UV adhesive film, so that the fuel cell stack can be easily assembled.

[0114] Second, in the event of a defect or failure in a specific fuel cell among the multiple fuel cells forming the fuel cell stack, by irradiating UV light to the UV adhesive film included in the specific fuel cell, the UV adhesive film can lose its adhesive force, so that only the specific fuel cell (which is the fuel cell to be replaced) can be easily separated from the fuel cell stack without any damage, and can then be easily replaced with a new fuel cell.

[0115] Third, after the fuel cell to be replaced is separated from the fuel cell stack, in the case where the MEA included in the fuel cell to be replaced is defective, the hot melt adhesive can lose its adhesive force by heating, so that only the defective MEA can be easily separated from the fuel cell and then can be easily replaced with a new MEA.

[0116] The invention has been described in detail with reference to exemplary embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which may be defined by the appended claims and their equivalents.

Claims

1. A reusable fuel cell stack comprising: A fuel cell comprising a membrane electrode assembly, a first separator and a second separator stacked on both surfaces of the membrane electrode assembly; at least one subgasket secured to a periphery of the membrane electrode assembly; a hot melt adhesive applied to both surfaces of the at least one subgasket to be bonded to the inner surface of the first separator and the inner surface of the second separator; as well as A UV adhesive film is attached to the outer surface of the first separator and configured to be bonded to a third separator of another fuel cell, and is attached to the outer surface of the second separator and configured to be bonded to a fourth separator of yet another fuel cell.

2. The reoperable fuel cell stack according to claim 1, wherein: A first gasket is fixed to an inner surface of the first separator, wherein a second gasket is fixed to an inner surface of the second separator, and wherein the hot melt adhesive applied to both surfaces of the at least one subgasket is bonded to the first gasket and the second gasket, respectively.

3. The reworkable fuel cell stack according to claim 1, wherein: The at least one subgasket is provided in a structure configured so that the hot melt adhesive is applied to both surfaces thereof and is fixed to the periphery of a cathode of the membrane electrode assembly and the periphery of a gas diffusion layer stacked on the outer side of the cathode.

4. The reworkable fuel cell stack according to claim 2, wherein: The first gasket is bonded to the hot melt adhesive applied to one surface of the at least one subgasket, wherein the second gasket is bonded to the hot melt adhesive applied to the remaining surface of the at least one subgasket, and wherein one surface of both ends of the electrolyte membrane of the membrane electrode assembly is bonded to the hot melt adhesive applied to the remaining surface of the at least one subgasket.

5. The reworkable fuel cell stack according to claim 1, wherein: The at least one subgasket comprises: a first subgasket configured such that the hot melt adhesive is applied to both surfaces thereof, wherein the first subgasket is fixed to a periphery of a cathode of the membrane electrode assembly and a periphery of a gas diffusion layer stacked on an outer side of the cathode; and A second subgasket is configured such that the hot melt adhesive is applied to both surfaces thereof, and wherein the second subgasket is fixed to a periphery of an anode of the membrane electrode assembly and a periphery of a gas diffusion layer stacked on an outer side of the anode.

6. The reworkable fuel cell stack according to claim 5, wherein: The first separator is directly bonded to the hot melt adhesive applied to the outer surface of the first subgasket, wherein the second separator is directly bonded to the hot melt adhesive applied to the outer surface of the second subgasket, and wherein one surface and the remaining surface of the two ends of the electrolyte membrane of the membrane electrode assembly are bonded to the hot melt adhesive applied to the inner surface of the first subgasket and the inner surface of the second subgasket.

7. The reworkable fuel cell stack according to claim 2, wherein: The hot melt adhesive is selected from a polyolefin-based adhesive, a styrene butadiene rubber-based adhesive and a butyl rubber having a dispersion force of 20 mN / m or more and a polar force of 0.01-1.91 mN / m. wherein the hot melt adhesive is bonded to the at least one sub-gasket, the at least one sub-gasket being formed of polyethylene naphthalate (PEN), wherein the hot melt adhesive is bonded to the first gasket and the second gasket, the first gasket and the second gasket are formed of ethylene propylene diene monomer (EPDM), and Wherein, the hot melt adhesive is bonded to the electrolyte membrane of the membrane electrode assembly.

8. The reoperable fuel cell stack according to claim 1, wherein: The hot melt adhesive is one selected from a polyolefin-based adhesive having a softening point of 67° C. to 110° C., a styrene butadiene rubber-based adhesive, and butyl rubber.

9. The reworkable fuel cell stack according to claim 1, wherein: The UV adhesive film comprises: a film substrate formed of one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and an olefin-based material; and An adhesive is applied to both surfaces of the film substrate.

10. The reoperable fuel cell stack according to claim 9, wherein: The adhesive applied to both surfaces of the film substrate is one selected from acrylic materials, multifunctional acrylic polyurethane and epoxy acrylic resin.

11. The reworkable fuel cell stack according to claim 9, wherein: The adhesive applied to both surfaces of the film substrate includes 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO) as a photoinitiator for generating free radicals when the adhesive is irradiated with UV light.

12. The reworkable fuel cell stack according to claim 9, wherein: The adhesive applied to both surfaces of the film substrate includes a UV absorber or a light stabilizer for adjusting sensitivity to UV light. 13 . The reworkable fuel cell stack according to claim 1 , further comprising, in addition to the UV adhesive film, third gaskets between the first separator plate and the third separator plate and between the second separator plate and the fourth separator plate.

14. The reworkable fuel cell stack according to claim 2, wherein: The first and second spacers and the first and second gaskets are configured so that at least a portion of heat generated by UV light radiated to the UV adhesive film by a UV light irradiation device is isolated from the hot melt adhesive by the first and second spacers and the first and second gaskets.

15. The reoperable fuel cell stack according to claim 14, wherein: The amount of UV light radiated to the UV adhesive film by the UV light irradiation device is adjusted to be less than a specified level for a long period of time longer than a specified time, so as to avoid the heat generated by the UV light radiated to the UV adhesive film from heating the hot melt adhesive beyond the transition temperature of the hot melt adhesive.

16. The reoperable fuel cell stack of claim 1, wherein: The bonding area of ​​the UV adhesive film is reduced to be smaller than the application area of ​​the hot melt adhesive so that the heat capacity generated by the UV light radiated to the UV adhesive film is set to a level that cannot melt the hot melt adhesive.

17. A reoperable fuel cell stack comprising: A fuel cell comprising a membrane electrode assembly; a first separator and a second separator stacked on both surfaces of the membrane electrode assembly; at least one subgasket secured to a periphery of the membrane electrode assembly; as well as A hot melt adhesive is applied to both surfaces of the at least one subgasket to be bonded to the inner surface of the first separator and the inner surface of the second separator.

18. A method of repairing a re-operable fuel cell stack, the method comprising the steps of: irradiating UV light on a first UV adhesive film, so that the first UV adhesive film reduces its adhesive force, wherein the first UV adhesive film is bonded between an outer surface of a first separator of a first fuel cell and a third separator of a second fuel cell; radiating UV light on a second UV adhesive film, so that the second UV adhesive film reduces its adhesive force, wherein the second UV adhesive film is bonded between an outer surface of the second separator of the first fuel cell and a fourth separator of the third fuel cell; removing the first fuel cell; and A replacement fuel cell is inserted and bonded such that the replacement fuel cell is bonded to the third separator of the second fuel cell and the fourth separator of the third fuel cell.

19. The method according to claim 18, further comprising the steps of: heating a hot melt adhesive so that the hot melt adhesive reduces its adhesive force, wherein the hot melt adhesive is applied to both surfaces of a subgasket fixed to a periphery of a first membrane electrode assembly of the first fuel cell; removing the first membrane electrode assembly from the first fuel cell; and A replacement membrane electrode assembly is inserted and bonded into the first fuel cell so that the first fuel cell becomes the replacement fuel cell.

Images