Method for manufacturing membrane-electrode assembly capable of reducing consumption of electrolyte membrane

Abstract

The present disclosure relates to a method of manufacturing a membrane-electrode assembly capable of reducing consumption of an electrolyte membrane. Specifically, in the present disclosure, a polymer membrane replaces a non-reactive portion of a conventional electrolyte membrane, thereby making it possible to prevent waste of a high-priced electrolyte membrane. Accordingly, production of a membrane-electrode assembly is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a manufacturing method of a membrane-electrode assembly capable of reducing consumption of an electrolyte membrane. BACKGROUND

[0002] Generally, a membrane-electrode assembly (MEA) that is a main component of a fuel cell stack is configured to join a pair of electrodes containing a catalyst to opposite surfaces of an electrolyte membrane, which is referred to as a three-layer membrane-electrode assembly.

[0003] On the other hand, in order to easily handle the membrane-electrode assembly and to secure physical durability of the membrane-electrode assembly, a case in which a sub-gasket having an electrode window with an area equal to or slightly smaller than that of the electrode is included at the edge of each of the opposite surfaces of the membrane-electrode assembly is referred to as a five-layer membrane-electrode assembly.

[0004] FIG. 1 is a cross-sectional view schematically illustrating a conventional five-layer membrane-electrode assembly. Referring to FIG. 1, the membrane-electrode assembly includes an electrolyte membrane 91, a pair of electrodes 92 formed on opposite surfaces of the electrolyte membrane 91, and a sub-gasket 93 joined to the electrolyte membrane 91 around the electrodes 92.

[0005] The electrolyte membrane 91 is divided into a reaction portion 91a that interfaces with the electrodes 92 and a non-reaction portion 91b that interfaces with the sub-gasket 93. The non-reaction portion 91b is a portion that does not participate in oxidation and reduction reactions as electrode reactions. That is, the non-reaction portion 91b is a substantially wasted portion.

[0006] The electrolyte membrane 91 is a high-priced product, and thus the non-reaction portion 91b can cause an increase in the price of the membrane-electrode assembly.

[0007] The above information disclosed in the Background section is only for enhancing the understanding of the background of the present disclosure, and therefore it can contain information that does not constitute the prior art that is already known in this field to those skilled workers. SUMMARY

[0008] The present disclosure aims to solve the above problems associated with the prior art.

[0009] An object of the present disclosure is to provide a manufacturing method of a membrane-electrode assembly capable of minimizing waste of an electrolyte membrane, thereby securing the economy of product production.

[0010] Another object of the present disclosure is to provide a manufacturing method of a membrane-electrode assembly capable of improving productivity, thereby further improving the price competitiveness of products.

[0011] The object of the present disclosure is not limited to the above-mentioned object. The object of the present disclosure will be clearly understood from the following description, and the object of the present disclosure can be achieved by the means defined in the claims and combinations thereof.

[0012] In one aspect, the disclosure provides a method of manufacturing a membrane-electrode assembly, the method including: preparing an electrolyte sheet having a predetermined length and a predetermined width; forming a plurality of rows of electrode groups on the electrolyte sheet in a width direction thereof, each electrode group being configured such that a plurality of electrodes are disposed at a predetermined distance apart from each other in a length direction of the electrolyte sheet; cutting the electrolyte sheet between the electrode groups to obtain a plurality of stacks located in different planes; and joining sub-gaskets to opposite surfaces of each stack.

[0013] The electrode groups can be formed on opposite surfaces of the electrolyte sheet.

[0014] The electrode groups can be formed such that a ratio (B / A) of a distance (B) between the plurality of rows of electrode groups to a width (A) of each electrode is 0.1 to 0.5.

[0015] The stacks can be separated from each other such that each stack is located in a different plane from an adjacent stack.

[0016] The stacks obtained by cutting the electrolyte sheet between the electrode groups can be moved at different angles with respect to the electrolyte sheet such that the stacks are separated from each other to be located in different planes parallel to a plane in which the electrolyte sheet is located.

[0017] The stacks can include a first stack having (2n-1) rows of electrode groups (n is an integer of 1 or more) and a second stack having 2n rows of electrode groups (n is an integer of 1 or more).

[0018] The stacks can include a first stack having (3m+1) rows of electrode groups (m is an integer of 0 or more), a second stack having (3m+2) rows of electrode groups (m is an integer of 0 or more), and a third stack having (3m+3) rows of electrode groups (m is an integer of 0 or more).

[0019] The stacks can include a first stack having (4x+1) rows of electrode groups (x is an integer of 0 or more), a second stack having (4x+2) rows of electrode groups (x is an integer of 0 or more), a third stack having (4x+3) rows of electrode groups (x is an integer of 0 or more), and a fourth stack having (4x+4) rows of electrode groups (x is an integer of 0 or more).

[0020] Each stack can include each row of electrode groups and electrolyte membranes attached to each row of electrode groups; and the electrolyte membranes can be spaced apart from each other at a predetermined distance.

[0021] A width of each electrolyte membrane can be greater than a width of the electrode groups.

[0022] Each sub-gasket can include an electrode window formed through at a position corresponding to the electrode group to accommodate the electrode group; and at least one of the sub-gaskets bonded to the opposite surface of each stack can include a polymer film located in a space between the electrode windows, formed to have a width smaller than the space, the width formed to be equal to a distance between adjacent electrolyte membranes, and have a predetermined thickness.

[0023] The polymer film can have a thickness equal to a thickness of each electrolyte membrane.

[0024] When the sub-gaskets are bonded to the opposite surface of each stack, the polymer film and each electrolyte membrane can form the same plane.

[0025] The method can further include cutting a membrane-electrode assembly obtained by bonding the electrolyte membranes between the sub-gaskets, wherein the sub-gaskets and the polymer film are cut. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and other features of the present disclosure will now be described in detail with reference to some exemplary embodiments thereof, which are illustrated in the accompanying drawings, given by way of example only, and thus are not limitative of the present disclosure, and wherein:

[0027] FIG. 1 is a cross-sectional view schematically showing a conventional five-layer membrane-electrode assembly;

[0028] Figure 2 is a plan view showing an electrolyte sheet according to the present disclosure;

[0029] Figure 3 is a plan view showing a structure in which an electrode group is formed on the electrolyte sheet;

[0030] Figure 4 is a cross-sectional view taken along line a-a' of Figure 3 ;

[0031] Figure 5 is a reference view showing first and second stacks obtained by cutting the electrolyte sheet between the electrode groups;

[0032] Figure 6A is a plan view showing the first stack;

[0033] Figure 6B is a plan view showing the second stack;

[0034] Figure 7 is a reference view showing sub-gaskets bonded to the first stack;

[0035] Figure 8 is a plan view showing an upper sub-gasket according to the present disclosure;

[0036] Figure 9 is a cross-sectional view taken along line b-b' of Figure 8

[0037] Figure 10 is a plan view showing a lower sub-gasket according to the present disclosure;

[0038] Figure 11 is a cross-sectional view taken along line c-c' of Figure 10

[0039] Figure 12 is a cross-sectional view of a membrane-electrode assembly showing a sub-gasket being joined to an opposing surface of a first stack.

[0040] It is to be understood that the drawings are not necessarily to scale, and that the various preferred features of the present disclosure are presented in slightly simplified form to illustrate the basic principles of the present disclosure. Particular design features of the present disclosure disclosed herein, including for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and use environment.

[0041] In several of the figures of the drawings, reference characters refer to the same or equivalent parts throughout the several views of the disclosure. DETAILED DESCRIPTION

[0042] The above objects and other objects, features and advantages of the present disclosure will be more clearly understood from the preferred embodiments that follow, with reference to the accompanying drawings. However, the present disclosure is not limited to these embodiments and will be implemented in various forms. These embodiments are merely provided to provide a complete and thorough understanding of the disclosed content, and are sufficient to inform those skilled in the art of the technical idea of the present disclosure.

[0043] Throughout the description of the drawings, the same reference numerals refer to the same elements. In the drawings, the dimensions of structures are exaggerated for the sake of clarity. It will be understood that, although the terms "first", "second", etc. are used herein to describe various elements, these elements should not be limited by these terms since such terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure as defined by the appended claims. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0044] ​​It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. In addition, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "under" another element, it can be directly under the other element, or intervening elements can also be present.

[0045] Unless otherwise defined, all numbers, graphs and / or expressions reflecting numerical values in this specification are approximations. Accordingly, unless otherwise indicated, the terms "approximately," "about," or the like, can be understood to encompass a range of values that one of ordinary skill in art would consider in the light of the entirety of the specification to be a sound approximation. Additionally, when a range of values is disclosed, unless otherwise defined, the disclosure covers all values and / or ranges between the lowest and highest value inclusive of the lowest and highest value. Furthermore, when a range is disclosed, unless otherwise defined, the range includes all integers within the range.

[0046] The method of manufacturing a membrane-electrode assembly according to the present disclosure can be performed by the following steps: preparing an electrolyte sheet having a predetermined length and a predetermined width; forming a plurality of rows of electrode groups on the electrolyte sheet in a width direction thereof; cutting the electrolyte sheet between the electrode groups to obtain a plurality of stacks located in different planes; and joining a sub-gasket to opposite surfaces of each stack.

[0047] The above steps of the method of manufacturing a membrane-electrode assembly according to the present disclosure can be performed sequentially, and the method is not particularly limited. For example, the electrode groups can be transferred to opposite surfaces of the electrolyte sheet while the electrolyte sheet is continuously supplied in a roll-to-roll manner, the stacks can be spatially separated from each other after cutting the electrolyte sheet between the electrode groups, and a sub-gasket is joined to each stack.

[0048] Figure 2 is a plan view showing an electrolyte sheet 10. Referring to Figure 2 , the electrolyte sheet 10 can be formed to have a predetermined length L and a predetermined width W. The length L, the width W, and the thickness of the electrolyte sheet are not particularly limited and can be appropriately adjusted according to the purpose of use.

[0049] The electrolyte sheet 10 can include a perfluorosulfonic acid ionomer such as a perfluorosulfonic acid-polytetrafluoroethylene copolymer (Nafion).

[0050] Figure 3 is a plan view showing a structure in which the electrode groups 20 are formed on the electrolyte sheet 10. Referring to Figure 3 , each electrode group 20 can be configured such that a plurality of electrodes 20a are arranged at a predetermined distance apart from each other in the length direction of the electrolyte sheet 10.

[0051] According to the present disclosure, a plurality of rows of electrode groups 20 are formed on the electrolyte sheet 10 in the width direction of the electrolyte sheet 10, so that a plurality of membrane-electrode assemblies can be obtained at one time. Therefore, the productivity of the membrane-electrode assemblies is greatly improved.

[0052] Figure 4 is a cross-sectional view taken along the line a-a' of Figure 3 . Referring to Figure 4 , the electrodes 20a can be formed on the opposite surfaces of the electrolyte sheet 10.

[0053] The ratio (B / A) of the distance B between the electrode groups 20 formed in the plurality of rows to the width A of each electrode 20a can be 0.1 to 0.5. If the ratio is less than 0.1, the distance between the electrode groups 20 is too small, so that it is difficult to cut. If the ratio exceeds 0.5, the effect of reducing the consumption of the electrolyte sheet 10 can be small.

[0054] The thickness of each electrode 20a is not particularly limited and can be appropriately adjusted according to the purpose of use.

[0055] Subsequently, as shown in Figure 5 , the electrolyte sheet between the electrode groups 20 can be cut to separate a plurality of stacks from each other so that each stack is located in a different plane from the adjacent stack. Figure 5 A case in which the stack includes a first stack 30 having (2n-1) rows of electrode groups (n is an integer of 1 or more) and a second stack 40 having 2n rows of electrode groups (n is an integer of 1 or more) is shown.

[0056] Here, the "(2n-1) rows of electrode groups" refers to the (2n-1)th row of electrode groups from one side of the electrolyte sheet 10 in the width direction of the electrolyte sheet 10, and the "2n rows of electrode groups" refers to the 2nth row of electrode groups under the same conditions.

[0057] For example, the (2n-1)th row electrode group refers to the electrode group of the first row, the third row, the fifth row, and the like from one side of the electrolyte sheet 10 in the width direction of the electrolyte sheet 10, and the 2nth row electrode group refers to the electrode group of the second row, the fourth row, the sixth row, and the like from the same side of the electrolyte sheet 10.

[0058] However, the present disclosure is not limited thereto. The stack can include a first stack having (3m+1)th row electrode groups (m is an integer of 0 or more), a second stack having (3m+2)th row electrode groups (m is an integer of 0 or more), and a third stack having (3m+3)th row electrode groups (m is an integer of 0 or more).

[0059] In addition, the stack can include a first stack having (4x+1)th row electrode groups (x is an integer of 0 or more), a second stack having (4x+2)th row electrode groups (x is an integer of 0 or more), a third stack having (4x+3)th row electrode groups (x is an integer of 0 or more), and a fourth stack having (4x+4)th row electrode groups (x is an integer of 0 or more).

[0060] In addition, the stacks can be separated from each other randomly, rather than making the difference gradual, such that each stack is located in a different plane from an adjacent stack.

[0061] However, in the following description, for convenience of description, it will be assumed that the stacks according to the present disclosure are arranged in the manner shown in Figure 5 FIG. 1.

[0062] After the electrolyte sheet between the electrode groups is cut, the first stack 30 and the second stack 40 can be separated from each other, thereby being located in different planes. Here, "being located in different planes" means that the two stacks 30 and 40 are spatially separated from each other, thereby not overlapping each other. However, referring to Figure 5 , the end portions of the two stacks 30 and 40 are not cut, and thus are attached to each other. Therefore, the stacks cannot be moved to a space far from each other, but can be separated from each other upward and downward. Specifically, as shown in Figure 5 , the first stack 30 can be moved upward, and the second stack 40 can be moved downward. However, the present disclosure is not limited thereto. Only one of the stacks can be moved, such that the first stack 30 and the second stack 40 are located in different planes.

[0063] Figure 6A is a plan view showing the first stack 30, Figure 6B is a plan view showing the second stack 40.

[0064] Referring to Figure 6AThe first stack 30 can include the electrode groups 20 and the electrolyte membranes 31 attached to each row of the electrode groups 20. The width of the electrolyte membranes 31 can be greater than that of each electrode group 20, particularly each electrode 20a.

[0065] Each electrolyte membrane 31 can be spatially spaced apart from an adjacent electrolyte membrane 31. A polymer membrane (to be described below) to which a sub-gasket is attached can be inserted into a gap between the electrolyte membranes. Thus, compared to the conventional art, the non-reacting portion of the electrolyte membrane 31 not in contact with the electrode 20a is small, and thus the production economy of the membrane-electrode assembly can be ensured. This is equally applicable to the second stack 40 described below.

[0066] Referring to Figure 6B The second stack 40 can include the electrode groups 20 and the electrolyte membranes 41 attached to each row of the electrode groups 20. The width of the electrolyte membranes 41 can be greater than that of each electrode group 20, particularly each electrode 20a.

[0067] A sub-gasket can be joined to the opposite surfaces of the first stack 30 to obtain a membrane-electrode assembly.

[0068] Figure 7 is a reference diagram illustrating that a sub-gasket is joined to the first stack 30. Referring to Figure 7 The upper and lower sub-gaskets 50a and 50b can be joined to the opposite surfaces of the first stack 30, thereby being stacked.

[0069] Figure 8 is a plan view illustrating the upper sub-gasket 50a. Referring to Figure 8 The upper sub-gasket 50a can include electrode windows 51 formed through at positions corresponding to the electrode groups 20 to accommodate the electrode groups 20.

[0070] Figure 9 is a cross-sectional view taken along the line b-b' of Figure 8 Referring to Figure 9 The upper sub-gasket 50a can further include a polymer membrane 60 located in a space between the electrode windows 51, formed to have a width smaller than the space, formed to have a width equal to a distance between the adjacent electrolyte membranes 31 of the first stack 30, and have a predetermined thickness. For reference, in Figure 8 In the polymer membrane 60 is illustrated in a dotted line since the polymer membrane is located on a bottom surface of the upper sub-gasket 50a.

[0071] The width of the polymer membrane 60 must be equal to the distance between the adjacent electrolyte membranes 31 of the first stack 30 so that the polymer membrane 60 is located between the electrolyte membranes 31 in the same plane when the sub-gasket 50 is joined to the first stack 30 as described below.

[0072] The thickness of the polymer film 60 is not particularly limited. Preferably, the polymer film 60 is formed so that its thickness is equal to the thickness of the electrolyte film 31, or is twice or less the thickness of the electrolyte film 31. If the thickness of the polymer film 60 is less than the thickness of the electrolyte film 31 or exceeds twice the thickness of the electrolyte film 31, a step can be formed, and thus it can be difficult to maintain the air tightness.

[0073] The polymer film 60 can include one selected from the group consisting of polyurethane, epoxy resin, polyvinyl acetate, polyethylene terephthalate, polyethylene, and combinations thereof.

[0074] The polymer film 60 can be provided in the form of a film so that, when the polymer film 60 is attached to the bottom surface of the upper sub-gasket 50a with an adhesive or when the upper sub-gasket 50a is joined to the first stack 30, the polymer film 60 is disposed in place between the first stack 30.

[0075] Figure 10 is a plan view showing the lower sub-gasket 50b, Figure 11 is a cross-sectional view taken along the line c-c' of Figure 10 Referring to these drawings, the lower sub-gasket 50b can include an electrode window 51 formed through at a position corresponding to the electrode group 20 to accommodate the electrode group 20.

[0076] A sub-gasket 50 including a polymer film 60 has been described with reference to Figure 8 to Figure 11 However, the present disclosure is not limited thereto. The polymer film 60 can be formed to have an appropriate thickness so that the polymer film can be applied to both the upper sub-gasket 50a and the lower sub-gasket 50b.

[0077] Figure 12 is a cross-sectional view showing a membrane-electrode assembly configured so that the sub-gaskets 50 are joined to opposite surfaces of the first stack 30 in the manner shown in Figure 7 Referring to Figure 12 It can be seen that the electrodes 20a are inserted into the electrode windows of the sub-gaskets 50a and 50b. In addition, it can be seen that the polymer film 60 is inserted into the space between the electrolyte films 31 so that the electrolyte films 31 and the polymer film 60 form the same plane.

[0078] Subsequently, the membrane-electrode assembly is cut (d-d') between the electrolyte films 31 to obtain a membrane-electrode assembly including each row of the electrode groups 20. At this time, the sub-gaskets 50a and 50b and the polymer film 60 can also be cut (d-d') together.

[0079] The sub-gaskets 50 can be joined to the Figure 6BThe second stack 40 is formed on the opposite surface of the first stack 30. Details thereof are substantially the same as those of the first stack 30, and thus a description thereof will be omitted.

[0080] In the method of manufacturing a membrane-electrode assembly according to the present disclosure, a polymer film replaces a non-reactive portion of a conventional electrolyte membrane, thereby making it possible to prevent waste of a high-priced electrolyte membrane. Thus, it is possible to greatly improve the production economy of a membrane-electrode assembly.

[0081] In addition, in the method of manufacturing a membrane-electrode assembly according to the present disclosure, a plurality of electrode groups are formed on an electrolyte sheet, thereby making it possible to simultaneously manufacture a plurality of membrane-electrode assemblies. Thus, it is possible to significantly improve the price competitiveness of a membrane-electrode assembly.

[0082] From the foregoing, it is apparent that, according to the present disclosure, it is possible to minimize a non-reactive portion of an electrolyte membrane, thereby making it possible to ensure the production economy of a product.

[0083] In addition, according to the present disclosure, it is possible to simultaneously manufacture a plurality of membrane-electrode assemblies, thereby making it possible to significantly improve the price competitiveness of a product.

[0084] Effects of the present disclosure are not limited to those described above. It should be understood that effects of the present disclosure include all effects that can be inferred from the foregoing description of the present disclosure.

[0085] The present disclosure has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes can be made in these embodiments without departing from the principles and spirit of the present disclosure, and the scope of the present disclosure is defined by the appended claims and their equivalents.

Claims

1. A method of manufacturing a membrane-electrode assembly, comprising: preparing an electrolyte sheet having a predetermined length and a predetermined width; forming a plurality of rows of electrode groups on the electrolyte sheet in a width direction thereof, each of the electrode groups being configured such that a plurality of electrodes are arranged at a predetermined distance apart from each other in a length direction of the electrolyte sheet; cutting the electrolyte sheet between the plurality of rows of electrode groups to obtain a plurality of stacks located in different planes; and joining sub-gaskets to opposite surfaces of each of the plurality of stacks, wherein each of the plurality of stacks includes a plurality of electrode groups that are staggered with the plurality of electrode groups of an adjacent stack, wherein each stack includes a plurality of rows of electrode groups and electrolyte membranes attached to each row of electrode groups; and in each stack, each row of electrolyte membranes is spatially spaced apart from electrolyte membranes of an adjacent row, each sub-gasket includes electrode windows formed through at a position corresponding to the electrode groups to accommodate the electrode groups; and at least one of the sub-gaskets joined to the opposite surfaces of each stack includes a polymer film located in spaces between the electrode windows, formed to have a width smaller than the spaces, formed to be equal to a distance between adjacent electrolyte membranes, and having a predetermined thickness, for each stack, the polymer film of the attached sub-gasket is inserted into a gap between electrolyte membranes. 2.The method according to claim 1, wherein the electrode groups are formed such that a ratio B / A of a distance B between adjacent rows of the electrode groups to a width A of each electrode in a width direction of the electrolyte sheet is 0.1 to 0.

5. 3.The method according to claim 1, wherein the plurality of stacks are separated from each other such that each of the plurality of stacks is located in a different plane from an adjacent stack. 4.The method according to claim 3, wherein the plurality of stacks obtained by cutting the electrolyte sheet between the electrode groups are moved at different angles with respect to the electrolyte sheet such that the plurality of stacks are separated from each other to be located in different planes parallel to a plane in which the electrolyte sheet is located. 5.The method according to claim 1, wherein the plurality of stacks include a first stack having 2n-1 rows of electrode groups and a second stack having 2n rows of electrode groups, where n is an integer of 1 or more. 6.The method according to claim 1, wherein the plurality of stacks include a first stack having 3m+1 rows of electrode groups, a second stack having 3m+2 rows of electrode groups, and a third stack having 3m+3 rows of electrode groups, where m is an integer of 0 or more. 7.The method according to claim 1, wherein the plurality of stacks include a first stack having 4x+1 rows of electrode groups, a second stack having 4x+2 rows of electrode groups, a third stack having 4x+3 rows of electrode groups, and a fourth stack having 4x+4 rows of electrode groups, where x is an integer of 0 or more. 8.The method according to claim 1, wherein a width of each electrolyte membrane is greater than a width of the electrode groups.

9. The method of claim 1, wherein, the thickness of the polymer film is equal to the thickness of the electrolyte film.

10. The method of claim 1, wherein, the polymer film and each electrolyte film form a same plane when the sub-gaskets are joined to the opposing surfaces of each stack.

11. The method of claim 1, further comprising: cutting the membrane-electrode assembly obtained by joining the electrolyte films between the sub-gaskets, wherein the sub-gaskets and the polymer film are cut.

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