Deformation-resistant fuel cell stack

Abstract

Fuel cell stack (100), comprising: a fuel cell stack module (1) having end plates (3) attached to opposite side surfaces of a fuel cell stack (100), and coupling rods (2) each coupled to the end plates (3); and a housing (12, 14, 16, 18) with an upper casing (12) covering a portion of a front surface, an upper surface and a portion of the rear surface of the fuel cell stack module (1), a lower casing (14) covering a portion of the front surface, a lower surface and a portion of the rear surface of the fuel cell stack module (1), a left housing (16) attached to one of the end plates (3) and a right housing (18) attached to the other end plate (3), wherein the upper housing (12) and the lower housing (14) are coupled to protruding portions of the left housing (16) and the right housing (18) that protrude forward and backward at side ends of each of the front and rear surfaces of the fuel cell stack module (1), and wherein the upper casing (12) and the lower casing (14) are bent from the protruding portions toward the surfaces of the fuel cell stack module (1) and are in surface contact with the surfaces of the fuel cell stack module (1).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a fuel cell stack, and more particularly, to a fuel cell stack capable of preventing a fuel cell stack module from being deformed in a vehicle accident. Description of related technology

[0002] A polymer electrolyte membrane fuel cell (PEMFC) or proton exchange membrane fuel cell is a device that generates electricity and water through an electrochemical reaction between hydrogen and oxygen. Its advantages include high energy efficiency, high current density, high output power density, short start-up time, and rapid response to load changes compared to other fuel cell types.

[0003] A general fuel cell stack comprises a membrane electrode assembly (MEA) containing a solid polymer electrolyte membrane through which hydrogen ions can migrate, and electrode layers (i.e., anode and cathode) arranged on the two opposite major surfaces of the solid polymer electrolyte membrane and coated with a catalyst that promotes the reaction between hydrogen and oxygen.

[0004] On the outer surface of each electrode layer, i.e., anode or cathode, a gas diffusion layer (GDL) and a sealing layer are stacked in that order. Separators with flow fields are provided on the outer surfaces of the GDLs. These flow fields serve as channels for the reactant gases (i.e., hydrogen as fuel and air with oxygen as oxidant) and for coolant. End plates supporting each component are connected to the outermost components to provide a compact structure.

[0005] Fig. 1 is a perspective view schematically illustrating a fuel cell stack according to the conventional art. A fuel cell stack module 1 according to the conventional art typically contains 200 to 400 fuel cells. To obtain a fuel cell stack module 1 consisting of a plurality of fuel cells, end plates 3 are arranged on the two opposite side surfaces of a fuel cell stack, applied with a necessary pressure, and coupled to the fuel cell stack with coupling rods 2. The fuel cell stacks arranged between the two end plates 3 are assembled into a single body by fastening the respective ends of the coupling rods 2 to the end plates 3 with screws.

[0006] The method using the coupling rods 2 for assembling the fuel cell stack module 1 has the advantage of applying sufficient surface pressure to the fuel cell stack module 1 and reducing the volume of the fuel cell stack module 1. However, the fuel cell stack module 1 assembled according to this method is susceptible to bending and twisting in the X and Z directions in the event of an accident. Fig. Figures 2A to 2C show such bending and twisting movements in the X and Z directions after an accident.

[0007] In the Fig. 2A to 2C, the fuel cell stack module 1 assembled with the coupling rods 2 is deformed and likely to malfunction upon impact. This may cause a short circuit in the fuel cell stack module 1 and ultimately a fire. Thus, there is a need for a structure that can prevent damage to the fuel cell in the event of an impact. Fuel cell casings can also be found in WO 2013 / 111669 A1 and DE 11 2013 000 719 T5.

[0008] The above description is provided only for understanding the background of the present invention and should not be construed as including the present invention in the prior art known to those skilled in the art. SUMMARY OF THE INVENTION

[0009] Accordingly, the present invention has been made in view of the above problems in the related art, and the present invention is intended to propose a fuel cell stack that can prevent a fuel cell stack module from being deformed under an impact load of a fuel cell vehicle.

[0010] According to one aspect, a fuel cell stack is provided, comprising: a fuel cell stack module having end plates attached to opposite side surfaces of a fuel cell stack and having coupling rods connected to the end plates; and a casing including an upper casing covering a portion of a front surface, an upper surface, and a portion of the rear surface of the fuel cell stack module, a lower casing covering a portion of the front surface, a lower surface, and a portion of the rear surface of the fuel cell stack module, a left casing attached to one of the end plates, and a right casing attached to the other end plate, wherein the upper and lower casings are connected to projecting portions of the left and right casings,which protrude forward and backward at the lateral ends of each of the front and rear surfaces of the fuel cell stack module. Specifically, the upper and lower casings are bent from the protruding portions toward the surfaces of the fuel cell stack module so that they are in surface contact with the surfaces of the fuel cell stack module.

[0011] Furthermore, at least a portion of an upper surface of the housing may be in surface contact with the upper surface of the fuel cell stack module. The portion of the upper surface of the upper housing that is in contact with the upper surface of the fuel cell stack module may be a corner portion between the front surface and the upper surface of the fuel cell stack module.

[0012] At least a portion of the lower housing may be in surface contact with the lower surface of the fuel cell stack.

[0013] The portion of the lower surface of the lower case in contact with the lower surface of the fuel cell stack may be a corner portion between the front surface and the lower surface of the fuel cell stack module.

[0014] A corner portion between a front or a rear surface and an upper surface of the upper case may be in surface contact with a corner portion between the front or rear surface and the upper surface of the fuel cell stack module.

[0015] A corner portion between a front or rear surface and a bottom surface of the lower housing may be in surface contact with a corner portion between the front or rear surface and the bottom surface of the fuel cell stack. The left housing may be integrated with one of the end plates, and the right housing may be integrated with the other end plate.

[0016] According to another aspect, there is provided a fuel cell stack comprising: a fuel cell stack module having end plates attached to two opposite side surfaces of a fuel cell stack and having coupling rods connected to the end plates; and a casing including an upper casing covering a portion of a front surface, an upper surface, and a portion of a rear surface of the fuel cell stack module, a lower casing covering a portion of the front surface, a lower surface, and a portion of the rear surface of the fuel cell stack, a left casing attached to one of the end plates, and a right casing attached to the other end plate.The upper and lower casings may be bent from the end plates to the surfaces of the fuel cell stack module to correspond to the step portions formed by the fuel cell stack and the end plates of the fuel cell stack module, such that the upper and lower casings are in surface contact with at least a part of the fuel cell stack module.

[0017] A fuel cell stack according to an embodiment includes a housing that can prevent deformation of the fuel cell structure upon impact, particularly in a fuel cell vehicle, due to improved rigidity of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a perspective view schematically illustrating a fuel cell stack module according to a conventional technique; Fig. 2A to 2C are perspective views showing bending and twisting of a fuel cell stack when the fuel cell stack is assembled by means of coupling rods; Fig. 3 is an exploded perspective view of a fuel cell stack according to an embodiment of the present invention; Fig. 4 is a sectional view of the fuel cell stack according to an embodiment of the present invention; Fig. 5A and Fig. 5B are sectional views showing a portion of the fuel cell stack of Fig. 4 show; Fig. 6A and Fig. 6B Sectional views of the fuel cell stack along the line AA' in Fig. 3, and Fig. 6C and Fig. 6D sectional views of the fuel cell stack along the line BB' in Fig. 3. DETAILED DESCRIPTION OF THE INVENTION

[0019] Specific structural and functional descriptions of embodiments of the present invention disclosed herein are intended only to exemplify embodiments of the present invention. The present invention may be embodied in numerous different forms without departing from the spirit and essential characteristics of the present invention. Therefore, the embodiments of the present invention are disclosed for exemplary purposes only and should not be construed as limiting the present invention.

[0020] Although terms such as "first," "second," "second," and the like may be used to describe various elements, it should be understood that these elements are not limited by these terms. The terms are used only to distinguish one element from another. For example, a first element discussed below may be referred to as a second element and the second element as a first element without departing from the teachings of the present invention.

[0021] When one element is described as being "connected" or "coupled" to another, it is understood that it may be directly connected or coupled to another, or that intervening elements may be provided. However, when an element is described as "directly connected" or "directly coupled" to another element, it is understood that no other element is present between them. Other expressions describing relationships between elements, such as "between," "directly between," "adjacent," or "directly adjacent," are to be understood in the same way.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, it is understood that the terms “comprising,” “including,” “having,” etc., when used in this specification, indicate the presence of stated features, integer quantities, steps, operations, elements, components, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, integer quantities, steps, operations, elements, components, and / or combinations thereof.

[0023] All terms used herein, including technical or scientific terms, have the same meaning as those commonly understood by one of ordinary skill in the art to which the present invention applies. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood in the same way as they would be in the context of the relevant technology and should not be interpreted in an ideal or overly formal sense unless clearly defined otherwise.

[0024] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Throughout the drawings, identical reference numerals designate the same or similar parts.

[0025] Fig. 3 is an exploded perspective view of a fuel cell stack according to an embodiment of the present invention. A fuel cell stack module 1 according to an embodiment of the present invention has a multi-layer structure consisting of an MEA, GDLs, and separators stacked one after the other. End plates 3 are arranged on two opposite side surfaces of the fuel cell stack module 1. Coupling rods 2 are coupled to the end plates.

[0026] Specifically, the fuel cell stack 100 includes the fuel cell stack module 1 and a casing (consisting of 12, 14, 16, and 18) that covers the surfaces of the fuel cell stack module 1. The casing includes an upper casing 12, a lower casing 14, a left casing 16, and a right casing 18. The left casing 16 and the right casing 18 may be integrated with the end plates 3.

[0027] Specifically, the upper case 12 covers the front surface, the rear surface, and the upper surface of the fuel cell stack module 1, and the lower case covers the front surface, the rear surface, and the lower surface of the fuel cell stack module 1. More specifically, the upper case 12 includes a front surface part 12b covering a portion of the front surface of the fuel cell stack module 1, a rear surface part 12c covering a portion of the rear surface of the fuel cell stack module 1, and an upper surface part 12a covering the upper surface of the fuel cell stack module 1.The lower case 14 includes a front surface part 14b covering a portion of the front surface of the fuel cell stack module 1, a rear surface part 14c covering a portion of the rear surface of the fuel cell stack module 1, and a lower surface part 14a covering a portion of the lower surface of the fuel cell stack module 1. The front surface of the fuel cell stack module 1 is covered by the front part 12b of the upper case 12 and the front surface part 14b of the lower case 14. A combination of the front surface part 12b of the upper case 12 and the front surface part 14b of the lower case 14 may be referred to as a front case 13. The rear surface of the fuel cell stack module 1 is covered by the rear surface part 12c of the upper case 12 and the rear surface part 14c of the lower case 14.A combination of the rear surface part 12c of the upper housing 12 and the rear surface part 14c of the lower housing 14 may be referred to as a rear housing 15.

[0028] Fig. 4 is a sectional view of the fuel cell stack according to an embodiment of the present invention. Fig. 5A and Fig. 5B are sectional views showing a portion of the fuel cell stack of Fig. 4. In the Fig. 4, Fig. 5A and Fig. 5B shows Fig. 4 a state in which at least a portion of the upper surface part 12a of the upper case 12 can be in surface contact with the upper surface of the fuel cell stack module 1, Fig. 5A shows a corner section 26 of Fig. 4 in enlarged view and Fig. 5B shows a state in which a portion of the upper surface part 12a of the upper case 12 and at least a portion of the front surface part 12b of the upper case 12 can be in surface contact with the upper surface and the front surface of the fuel cell stack module 1, respectively. Fig. 4 to 5B, the portion of the upper surface part 12a of the upper case 12 that can be in surface contact with the upper surface of the fuel cell stack module 1 and the portion of the front surface part 12b of the upper case 12 that can be in surface contact with the front surface of the fuel cell stack module 1 may be a corner portion 26 between the front surface and the upper surface of the fuel cell stack 1.

[0029] This positional relationship may also apply between the upper surface part 12a and the rear surface part 12c of the upper case 12, between the lower surface part 14a and the front surface part 14b of the lower case 14, and between the lower surface part 14a and the rear surface part 14b of the lower case 14. This corner portion between the front or rear surface and the upper surface of the fuel cell stack module 1 may be in surface contact with the corner portion 26 between the front surface part 12b or the rear surface part 12c and the upper surface part 12a of the upper case 12. The corner portion between the front or rear surface and the lower surface of the fuel cell stack 1 may be in surface contact with the corner portion 26 between the front surface part 14b or the rear surface part 14c and the lower surface part 14a of the lower case 14.

[0030] The Fig. 6A to 6B are sectional views of the fuel cell stack 100 along the line AA' in Fig. 3, and the Fig. 6C to 6D are sectional views of the fuel cell stack 100 taken along line B-B'. The end plates 3 are attached to the two opposite side surfaces of the fuel cell stack module 1. The left housing 16 and the right housing 18 may be integrated with the end plates 3.

[0031] The fuel cell stack module 1 must be connected to an interface for supplying reaction gases. The interface can be connected to the two opposite side surfaces or to one side surface of the fuel cell stack module 1. For this connection, the end plates 3 protrude from the front and rear surfaces of the fuel cell stack module 1 to form protruding sections or stepped sections.

[0032] Thus, the upper case 12 and the lower case 14 can be combined with the protruding portions 22 and extend inward into the fuel cell stack module 1. The upper case 12 and the lower case 14 can be formed to ensure surface contact with the fuel cell stack module 1. That is, the end plates 3 or the left and right cases 16 and 18 can be combined with the respective side ends of each front surface part 12b and 14b of the upper case 12 and the lower case 14.

[0033] Fig. 6C shows the example in which the end plates 3 and the left and right housings 16 and 18 are formed separately. Fig. 6D shows the example in which the end plates 3 and the left and right housings 16 and 18 are formed integrally with each other.

[0034] If the front surface parts 12b and 14b of the upper case 12 and the lower case 14 are flat in the state where the upper case 12 and the lower case 14 are combined with the left case 16 and the right case 18, deformation of the fuel cell stack module 1 in a vehicle accident cannot be prevented. Therefore, the side ends of the front surface parts 12b and 14b of the upper case 12 and the lower case 14 are formed as shown in Fig. 6C, the left and right casings 16 and 18 are combined and bent into the fuel cell stack module 1 so that they can be in surface contact with the fuel cell stack 1. As can be seen, the rear surface parts 12c and 14c of the upper casing 12 and the lower casing 14 have the same structure.

[0035] That is, the front surface parts 12b and 14b and the rear surface parts 12c and 14c can be bent inward from the protruding portions or step portions 22 (ie, toward the front and rear surfaces of the fuel cell stack module 1) so that they are partially in surface contact with the fuel cell stack module 1. Since Fig. 6A is a sectional view along the line AA' in Fig. 3, it is not insignificant for the shape of the projecting sections or step sections 22. That is, Fig. 6A shows a central portion of the fuel cell stack module 1 and a connecting structure of the upper case 12 and the lower case 14. As shown in the Fig. 6A and Fig. 6B, at least parts of the surface parts 12b and 14b of the upper case 12 and the lower case 14 are in surface contact with the fuel cell stack module 1 at positions other than the corner portions of the fuel cell stack module 1.

[0036] That is, the entire front surface of the fuel cell stack module 1 except the corner portion is in surface contact with the front surface parts 12b and 14b of the upper case 12 and the lower case 14, as shown in Fig. 6A. As further shown in Fig. 6B, some portions of the front surface parts 12b and 14b of the upper case 12 and the lower case 14 other than the corner portions can be separated from the front surface of the fuel cell stack module 1.

[0037] Since the fuel cell stack module 1 is supported or fixed by this structure, deformation of the fuel cell stack module 1 under impact load can be prevented.

Claims

[1] Fuel cell stack (100), comprising: a fuel cell stack module (1) having end plates (3) attached to opposite side surfaces of a fuel cell stack (100), and coupling rods (2) each coupled to the end plates (3); and a housing (12, 14, 16, 18) with an upper casing (12) covering a portion of a front surface, an upper surface and a portion of the rear surface of the fuel cell stack module (1), a lower casing (14) covering a portion of the front surface, a lower surface and a portion of the rear surface of the fuel cell stack module (1), a left housing (16) attached to one of the end plates (3) and a right housing (18) attached to the other end plate (3), wherein the upper housing (12) and the lower housing (14) are coupled to protruding portions of the left housing (16) and the right housing (18) that protrude forward and backward at side ends of each of the front and rear surfaces of the fuel cell stack module (1), and wherein the upper casing (12) and the lower casing (14) are bent from the protruding portions toward the surfaces of the fuel cell stack module (1) and are in surface contact with the surfaces of the fuel cell stack module (1). [2] The fuel cell stack (100) of claim 1, wherein at least a portion of the upper surface of the upper casing (12) is in surface contact with the upper surface of the fuel cell stack module (1). [3] The fuel cell stack (100) according to claim 2, wherein the portion of the upper surface of the upper case (12) in contact with the upper surface of the fuel cell stack module (1) is a corner portion (26) between the front surface and the upper surface of the fuel cell stack module (1). [4] The fuel cell stack (100) of claim 1, wherein at least a portion of the lower surface of the lower housing (14) is in surface contact with the lower surface of the fuel cell stack (100). [5] The fuel cell stack (100) according to claim 4, wherein the portion of the lower surface of the lower case (14) in contact with the lower surface of the fuel cell stack (100) is a corner portion (26) between the front surface and the lower surface of the fuel cell stack module (1). [6] The fuel cell stack (100) according to claim 1, wherein a corner portion (26) between the front or rear surface and the upper surface of the upper case (12) is in surface contact with a corner portion (26) between the front surface or the rear surface and the upper surface of the fuel cell stack module (1). [7] The fuel cell stack (100) according to claim 1, wherein a corner portion (26) between the front surface or the rear surface and the lower surface of the lower case (14) is in surface contact with a corner portion (26) between the front surface or the rear surface and the lower surface of the fuel cell stack (100). [8] The fuel cell stack (100) according to claim 1, wherein the left housing (16) is integrated with the first end plate (3) and the right housing (18) is integrated with the second end plate (3). [9] Fuel cell stack (100), comprising: a fuel cell stack module (1) having end plates (3) attached to two opposite side surfaces of a fuel cell stack (100), and coupling rods (2) each coupled to the end plates (3); and a housing (12, 14, 16, 18) with an upper casing (12) covering a portion of a front surface, an upper surface and a portion of the rear surface of the fuel cell stack module (1), a lower casing (14) covering a portion of the front surface, a lower surface and a portion of the rear surface of the fuel cell stack module (1), a left housing (16) attached to one of the end plates (3) and a right housing (18) attached to the other end plate, wherein the upper housing (12) and the lower housing (14) are bent from the end plates (3) to the surfaces of the fuel cell stack module (1) so as to correspond to the step portions formed by the fuel cell stack (100) and the end plates (3) of the fuel cell stack module (1), so that the upper housing (12) and the lower housing (14) are in surface contact with at least a part of the fuel cell stack module (1).

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