Fuel cell

Abstract

A fuel cell (100) includes: a cell stack (10) formed by alternately stacking membrane electrode assemblies (2) and separators, the membrane electrode assembly (2) including an electrolyte membrane and an electrode; a case (50) that houses the cell stack (10); and a plurality of rod-shaped members (60a to 60d) that extend in a stacking direction in a manner of dividing a cylindrical space (SP30) formed between a side surface (10a) of the cell stack (10) and an inner surface (31a) of the case (50) into a plurality of spaces (SP31 to SP34) in the stacking direction, and that closely adhere or approach an end surface (61) on one end side to the inner surface (31a) of the case (50) and an end surface (62) on the other end side to the side surface (10a) of the cell stack (10). A plurality of openings (52 to 55) that respectively communicate the plurality of spaces (SP31 to SP34) with an outside space (EX) of the case (50) are provided in the case (50).

Description

Technical Field

[0001] This invention relates to a fuel cell. Background Technology

[0002] Previously, there were known vehicle-mounted fuel cells that discharged hydrogen gas leaking from the battery stack constituting the fuel cell to the outside (see, for example, Patent Document 1). In the fuel cell described in Patent Document 1, an opening is provided on the wall of the housing that houses the battery stack, in front of it where the driving wind blows, and each opening is provided with a slit-shaped air inlet channel that slopes upward from the outside of the housing inward.

[0003] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2022-128982 (JP2022-128982A). Summary of the Invention

[0004] The problem the invention aims to solve However, in the aforementioned patent document 1, an opening is provided only on one wall of the casing. Therefore, when the space between the battery stack and the casing is divided into multiple parts, hydrogen gas is trapped in a portion of the space, making it difficult to fully ventilate the entire space.

[0005] Solution for solving the problem A fuel cell according to one embodiment of the present invention comprises: a battery stack formed by alternately stacking membrane electrode structures and separators, the membrane electrode structures including an electrolyte membrane and electrodes; a housing housing the battery stack; and a plurality of rod-shaped members extending in the stacking direction such that they divide a cylindrical space formed between the side surface of the battery stack and the inner surface of the housing into a plurality of spaces substantially parallel to the stacking direction of the battery stack, and one end face of the rod-shaped members is in close contact with or close to the inner surface of the housing, and the other end face of the rod-shaped members is in close contact with or close to the side surface of the battery stack. The housing is provided with a plurality of openings that communicate with the external space of the housing.

[0006] Invention Effects Using this invention, even when the space between the battery stack and the casing is divided into multiple parts, the entire space can be fully ventilated. Attached Figure Description

[0007] Figure 1 This is a perspective view schematically illustrating a battery stack of a fuel cell according to an embodiment of the present invention; Figure 2 It is a general description of the containment Figure 1 A cross-sectional view of an example of the internal structure of the battery stack housing; Figure 3A It is shown in general terms. Figure 2 A perspective view of an example of the external structure of the shell; Figure 3B It is a different perspective. Figure 3A A three-dimensional view of the shell; Figure 3C It is an observation from another perspective Figure 3A A three-dimensional view of the shell. Detailed Implementation

[0008] The following is for reference Figures 1 to 3C Embodiments of the present invention will be described. The fuel cell of the present invention, for example, is mounted in a vehicle and can generate electricity for vehicle propulsion. The fuel cell can be mounted not only in mobile bodies other than vehicles such as aircraft and ships, and robots, but also in various industrial machinery.

[0009] Figure 1 This is a perspective view schematically showing the battery stack 10 of a fuel cell 100 according to an embodiment of the present invention. Hereinafter, for convenience, the three mutually orthogonal axial directions are defined as the front-rear direction, the left-right direction, and the up-down direction, and the structure of each part will be described according to these definitions. The up-down direction is the direction approximately the same as the direction of gravity. The front-rear direction and the left-right direction are not necessarily the same as the front-rear direction and the left-right direction of a vehicle. For example, the front-rear direction can be the front-rear direction of the vehicle, the left-right direction of the vehicle, or the direction between the front-rear direction and the left-right direction of the vehicle.

[0010] like Figure 1 As shown, the battery stack 10 is constructed by stacking multiple power generation cells 1 in the front-to-back direction (for simplicity, only a single power generation cell is shown). Each power generation cell 1 is generally rectangular, and the battery stack 10 is generally cuboid in shape. Each power generation cell 1 has: a united electrode assembly (UEA) 2, which is a membrane electrode structure including an electrolyte membrane and electrodes; and a separator 3, which is disposed on the front and rear sides of the united electrode assembly 2, clamping the united electrode assembly 2. The united electrode assembly 2 and the separator 3 are alternately arranged in the front-to-back direction.

[0011] End units 20 are disposed adjacent to the battery stack 10 on both ends of the battery stack 10 in the front-rear direction. In addition to the metal end plate 21, the end unit 20 also includes an insulator and a terminal plate located inside the end plate 21 in the front-rear direction.

[0012] The side surfaces of the battery stack 10 are surrounded by a stack shell 30. The stack shell 30 has four generally rectangular sidewalls 31 facing the upper, right, lower, and left surfaces of the battery stack 10, respectively. The front and rear surfaces of the stack shell 30 are covered by end units 20 (end plates 21). The stack shell 30 is made of metals such as aluminum or iron.

[0013] The integrated electrode assembly 2 has a generally rectangular membrane electrode assembly (MEA) and a resin frame supporting the MEA. The MEA has an electrolyte membrane and an anode and a cathode electrode respectively disposed on the front and rear surfaces of the electrolyte membrane. The electrolyte membrane is, for example, a solid polymer electrolyte membrane. Each electrode is an electrode catalyst layer formed on the front and rear surfaces of the electrolyte membrane, serving as the reaction field for the electrode reaction. Gas diffusion layers for diffusing and supplying fuel gas and oxidant gas are respectively disposed on the front and rear surfaces of the electrode catalyst layers.

[0014] At the anode electrode, the fuel gas (hydrogen) supplied via the gas diffusion layer is ionized by the catalyst and moves through the electrolyte membrane toward the cathode electrode. The electrons generated are extracted as electrical energy via an external circuit. At the cathode electrode, the oxidant gas (oxygen) supplied via the gas diffusion layer reacts with hydrogen ions introduced from the anode electrode and electrons moving from the anode electrode to produce water. The generated water provides appropriate humidity to the electrolyte membrane, and any remaining water is discharged to the outside of the integrated electrode assembly 2.

[0015] The separator 3 has a pair of thin metal plates with a corrugated cross-section, which are joined together at their outer peripheries to form a single unit. The separator 3 is made of a conductive material with excellent corrosion resistance, such as titanium, titanium alloy, or stainless steel. The pair of thin plates are formed into an uneven shape by stamping or other methods to create cooling channels inside the separator 3 for the flow of a cooling medium (e.g., water), thereby cooling the power generation surface of the power generation cell 1.

[0016] The front partition 3 of the integrated electrode assembly 2 is, for example, an anode-side partition (anode partition), forming an anode flow channel for the flow of hydrogen-containing fuel gas between the anode partition 3 and the integrated electrode assembly 2. The rear partition 3 of the integrated electrode assembly 2 is, for example, a cathode-side partition (cathode partition), forming a cathode flow channel for the flow of oxygen-containing oxidant gas between the cathode partition 3 and the integrated electrode assembly 2.

[0017] Through holes 211 to 216 are provided in the rear end unit 20. Through hole 211 is for supplying fuel gas to the interior of the battery stack 10. Through hole 212 is for discharging cooling medium from the battery stack 10 to the outside. Through hole 213 is for discharging oxidant gas from the battery stack 10 to the outside. Through hole 214 is for supplying oxidant gas to the interior of the battery stack 10. Through hole 215 is for supplying cooling medium to the interior of the battery stack 10. Through hole 216 is for discharging fuel gas from the battery stack 10 to the outside.

[0018] Multiple flow channels (manifolds) extending in the front-rear direction are formed at both ends of the battery stack 10 in the left-right direction, communicating with through holes 211-216. Fuel gas supplied through through hole 211 is introduced into the anode flow channel inside the battery stack 10, and oxidant gas supplied through through hole 214 is introduced into the cathode flow channel. This generates electricity in the power generation cell 1. The supplied fuel gas and oxidant gas are discharged from the battery stack 10 through through holes 216 and 213, respectively. Cooling medium supplied through through hole 215 is introduced into the battery stack 10, thereby cooling the power generation surface. The cooling medium passing through the battery stack 10 is discharged through through hole 212.

[0019] Figure 2 It is along Figure 1 The cross-sectional view taken along line II-II schematically shows an example of the internal structure of the housing 50 that houses the battery stack 10. It should be noted that... Figure 2 For convenience, only the side surface 10a of the battery stack 10 is shown, i.e., only the outline is shown, and detailed drawings of the battery stack 10 are omitted. That is, in the configuration Figure 2 The integrated electrode assembly 2 and the separator 3 of the battery stack 10 are actually arranged in the vertical direction with three through holes that communicate with the through holes 211-213 and 214-216 of the end unit 20, respectively, but the illustration of these through holes is omitted.

[0020] like Figure 2 As shown, a VCU housing 40 is integrally disposed on the upper part of the stack housing 30 that houses the battery stack 10. The VCU housing 40 houses a voltage control unit (VCU) for controlling the voltage of the fuel cell. The VCU housing 40 is the same as the stack housing 30 and is made of metals such as aluminum or iron. The stack housing 30 and the VCU housing 40 constitute the housing 50 that mainly houses the battery stack 10.

[0021] The upper sidewall 31 of the stack housing 30 forms a partition separating the internal space of the stack housing 30 from the internal space SP40 of the VCU housing 40. A communication hole 51 is provided on the upper sidewall 31 of the stack housing 30, connecting the internal space of the stack housing 30 and the internal space SP40 of the VCU housing 40. The electrodes of the battery stack 10 housed in the stack housing 30 and the VCU housed in the VCU housing 40 are electrically connected by wires passing through the communication hole 51.

[0022] Between the side surface 10a of the battery stack 10 and the inner surface 31a of the side wall 31 of the stacked outer casing 30 constituting the inner surface of the casing 50, a cylindrical space SP30 extending in the front-rear direction is formed. Multiple (in) Figure 2 Four resin support members 60a to 60d support the battery stack 10. Each support member 60a to 60d is located at... Figure 1 The rear end unit 20 extends to the front end unit 20 in the front-rear direction. The space SP30 is divided by support members 60a to 60d into multiple L-shaped sections extending in the front-rear direction. Figure 2 (There are four spaces, SP31 to SP34)

[0023] Support member 60a is installed on the left side wall 31 of the reactor outer shell 30. Support member 60b is installed on the upper side wall 31 of the reactor outer shell 30. Support member 60c is installed on the right side wall 31 of the reactor outer shell 30. Support member 60d is installed on the lower side wall 31 of the reactor outer shell 30.

[0024] One end face 61 of each support member 60a to 60d is in close contact with or near the inner surface 31a of the side wall 31 of the stacked outer shell 30, which forms the inner surface of the shell 50; the other end face 62 is in close contact with or near the side surface 10a of the battery laminate 10. Figure 2 In the example, on one end face 61 of each support member 60a-60d, a pair of protrusions 63 are provided along the extending direction of the corresponding sidewall 31 and facing opposite directions. On the inner surface 31a of each sidewall 31, a pair of recesses 32 are provided along the extending direction and facing opposite directions. Furthermore, by fitting the protrusions 63 into the recesses 32, the end face 61 of each support member 60a-60d is in close contact with or near the inner surface 31a of the sidewall 31 of the stacked shell 30 that constitutes the inner surface of the shell 50.

[0025] Furthermore, on the end face 62 of each support member 60a-60d, a recess 64 is provided in a direction orthogonal to the corresponding side surface 10a, and a protrusion 11 is provided on each side surface 10a in a direction orthogonal to that side surface 10a. The protrusion 11 fits into the recess 64, thereby ensuring that the end face 62 of each support member 60a-60d is in close contact with or near the side surface 10a of the battery laminate 10. Considering the positions of the through holes provided at the left and right ends of the battery laminate 10, the protrusion 11 of the battery laminate 10 is positioned offset from the center in both the vertical and horizontal directions.

[0026] Thus, the battery stack 10 is supported by the sidewalls 31 of the stack casing 30 using support members 60a to 60d. By using resin support members 60a to 60d, insulation between the metal separators 3 of the battery stack 10 and the metal stack casing 30 can be ensured.

[0027] When the fuel cell 100 is mounted in a vehicle, inertial forces corresponding to the acceleration and impact forces acting on the vehicle act on the battery stack 10. When inertial forces act on the battery stack 10, especially in a direction orthogonal to the stacking direction, the resin support members 60a-60d with moderate hardness bear the forces from the battery stack 10, thereby suppressing displacement and deformation of the battery stack 10. As a result, it is possible to prevent the stack elements constituting the battery stack 10 (integrated electrode assembly 2, separator 3) from shifting position on the stacking surface, and to prevent hydrogen leakage from the stacking surface.

[0028] The support members 60a to 60d only need to be supported by the sidewalls 31 of the stack shell 30 and position the battery stack 10 in the vertical and horizontal directions orthogonal to the stacking direction. The cross-sectional shape of the support members 60a to 60d is not limited to... Figure 2 As shown. The cross-sectional shape of the support members 60a to 60d can also be formed such that there is a gap (clearance) between the end face 61 and the inner surface 31a of the side wall 31 of the stacked shell 30 that constitutes the inner surface of the shell 50, or between the end face 62 and the side surface 10a of the battery stack 10.

[0029] However, the gas flow channels (anode flow channels and cathode flow channels) formed between the integrated electrode assembly 2 and the separator 3 in the battery stack 10 are sealed by a sealing member, which is disposed between the integrated electrode assembly 2 and the separator 3 in a manner that surrounds the gas flow channels. Such a sealing member ensures airtightness by tightly adhering to the surfaces of the integrated electrode assembly 2 and the separator 3, and is therefore made of a flexible resin material such as rubber, possessing a certain degree of permeability. Therefore, a portion of the hydrogen-containing fuel gas permeates from the anode flow channel into the space SP30 between the battery stack 10 and the stack housing 30 through the sealing member, based on the pressure of the anode flow channel (the pressure difference between the anode and atmospheric pressure).

[0030] Therefore, in this embodiment, multiple openings 52-55 are provided in the external space EX connecting the space SP30 and the housing 50, so that by fully ventilating the entire space SP30, the concentration of hydrogen in the space SP30 can be maintained below the flammability limit (the lower limit of the combustion range). Each opening 52-55 is connected to each space SP31-SP34 and the external space EX.

[0031] Opening 52 is located on the left sidewall 31 of the stack housing 30. Opening 53 is located on the right sidewall 41 of the VCU housing 40. Opening 54 is located on the right sidewall 31 of the stack housing 30. Opening 55 is located on the lower sidewall 31 of the stack housing 30.

[0032] The space SP31 from support member 60a to support member 60b communicates with the external space EX via opening 52, and also via connecting hole 51 and opening 53. The space SP32 from support member 60b to support member 60c communicates with the external space EX via connecting hole 51 and opening 53. The space SP33 from support member 60c to support member 60d communicates with the external space EX via opening 54. The space SP34 from support member 60d to support member 60a communicates with the external space EX via opening 55.

[0033] The support members 60a to 60d are not necessarily in close contact with the inner surface 31a of the sidewall 31 of the stack shell 30 and the side surface 10a of the battery stack 10, and the spaces SP31 to SP34 are not completely sealed by the support members 60a to 60d. However, in each space SP31 to SP34 separated by the support members 60a to 60d, the concentration of hydrogen may locally increase. For example... Figure 2 As shown, by setting openings 52 to 55 that connect each space SP31 to SP34 with the external space EX, each space SP31 to SP34 can be reliably ventilated, and the entire space SP30 can be fully ventilated.

[0034] The opening 54 is located near the support member 60c, thus positioned above the gravity direction of space SP33. Hydrogen gas is extremely light and flows upward, so it does not stagnate in space SP33 and is smoothly discharged into the external space EX through the opening 54.

[0035] The opening 53 is located above spaces SP31 and SP32 and near the upper end of the side wall 41, thus positioned above the gravity direction of the internal space SP40 of the VCU housing 40. Therefore, hydrogen gas will not be trapped in spaces SP31 and SP32, but will be smoothly discharged to the external space EX through the connecting hole 51, the internal space SP40 of the VCU housing 40, and the opening 53.

[0036] Opening 52 is located near the support member 60a, thus positioned at the lower part of space SP31 in the direction of gravity. In other words, openings 52 and 53 connecting space SP31 and the outer space EX are located at different heights in the direction of gravity. Thus, space SP31 and the outer space EX are connected via a pair of openings 52 and 53 with a height difference h, thereby generating gas flow from opening 52 at the lower part of the direction of gravity to opening 53 at the upper part of the direction of gravity. In this case, hydrogen gas in space SP31 can be further and more smoothly discharged to the outer space EX.

[0037] Filter units 70 are provided at each of the openings 52-55. Each filter unit 70 includes: a cover 71, which is mounted to the side walls 31, 41 of the housing 50 (stack housing 30, VCU housing 40) from the external space EX side using bolts or the like; and a filter 72, which is fixedly mounted on the cover 71 to cover each of the openings 52-55. The cover 71 has a screen portion and a louver portion covering each of the openings 52-55 to prevent larger foreign objects from entering the housing 50 and to protect the filter 72. The filter 72 is an air filter that removes dust and other contaminants from the passing gas, especially air flowing into the housing 50 from the outside, preventing dust and other contaminants from entering the housing 50 and protecting the battery stack 10.

[0038] Figures 3A-3C This is a perspective view that schematically shows an example of the external structure of the housing 50. (See image below.) Figure 2 and Figure 3A As shown, a filter unit 70 is installed on the right side wall 41 of the VCU housing 40, which constitutes the housing 50, at a position corresponding to the opening 53. Additionally, a filter unit 70 is installed on the right side wall 31 of the stack housing 30, which constitutes the housing 50, at a position corresponding to the opening 54. Figure 2 and Figure 3B As shown, a filter unit 70 is installed on the left sidewall 31 of the stack shell 30 at a position corresponding to the opening 52. Figure 2 and Figure 3CAs shown, a filter unit 70 is installed on the lower side wall 31 of the stack shell 30 at a position corresponding to the opening 55. The openings 52-54 are arranged to extend in the front-rear direction. Figure 3A and Figure 3B In the example, multiple filter units 70 are installed adjacent to each other in the front-to-back direction at positions corresponding to each opening 52-54.

[0039] The following effects can be achieved by adopting this implementation method.

[0040] (1) The fuel cell 100 comprises: a battery stack 10, which is formed by alternately stacking an integrated electrode assembly 2 and a separator 3, wherein the integrated electrode assembly 2 is a membrane electrode structure including an electrolyte membrane and an electrode; a housing 50, which houses the battery stack 10; and a plurality of support members 60a to 60d, which extend in the front-back direction such that a cylindrical space SP30 formed between the side surface 10a of the battery stack 10 and the inner surface 31a of the side wall 31 of the stack shell 30 constituting the inner surface of the housing 50 is divided into a plurality of spaces SP31 to SP34 in the stacking direction of the battery stack 10, i.e., the front-back direction, and one end face 61 is in close contact or close to the inner surface 31a of the side wall 31 of the stack shell 30 constituting the inner surface of the housing 50, and the other end face 62 is in close contact or close to the side surface 10a of the battery stack 10. Figure 1 , Figure 2 ).

[0041] Multiple openings 52-55 are provided in the housing 50 to connect the spaces SP31-SP34 and the external space EX of the housing 50. Figure 2 , Figures 3A-3C In this way, by providing openings 52 to 55, each space SP31 to SP34 is connected to the external space EX, so even if the space SP30 between the battery stack 10 and the housing 50 is divided into multiple spaces, the entire space SP30 can be fully ventilated.

[0042] (2) Supporting components 60a~60d support the battery stack 10 ( Figure 2The support members 60a-60d include a pair of support members 60b and 60d and a pair of support members 60a and 60c. The end faces 62 of the other end of the pair of support members 60b and 60d are in close contact with or close to a pair of inner surfaces 31a of the housing 50 facing each other in the vertical direction, and the end faces 62 of the other end of the pair of support members 60a and 60c are in close contact with or close to a pair of inner surfaces 31a of the housing 50 facing each other in the horizontal direction. In this way, the support members 60a-60d that support the battery stack 10 from the vertical and horizontal directions bear the force from the battery stack 10 when the inertial force acts on the stacking direction of the battery stack 10, i.e., the front-back direction, thereby suppressing the displacement and deformation of the battery stack 10.

[0043] (3) A filter 72 is provided in each opening 52-55. This prevents foreign objects, dust and the like from entering the housing 50 through each opening 52-55, and protects the battery stack 10.

[0044] (4) Multiple openings 52-55 include a pair of openings 52, 53 that connect a specific space SP31 among multiple spaces SP31-SP34 with the external space EX. Figure 2 A pair of openings 52 and 53 are positioned at different heights in the direction of gravity. In this way, by connecting space SP31 and the outer space EX through a pair of openings 52 and 53 with a height difference h, a flow is generated from the lower opening 52 in the direction of gravity to the upper opening 53 in the direction of gravity, which can further facilitate the smooth discharge of hydrogen gas from space SP31 to the outer space EX.

[0045] (5) At least a portion of the openings 52 to 55, openings 53 and 54 are located in the upper part of the space SP31 to SP33, which are connected to the external space EX, in the direction of gravity. As a result, the extremely light and upward-flowing hydrogen gas will not be trapped in the space SP33 and can be smoothly discharged to the external space EX through the opening 54.

[0046] In the above embodiments, Figure 2 , Figures 3A-3C The specific configurations of openings 52 to 55 are illustrated and explained in the examples, but the number and location of the multiple openings are not limited to those illustrated. In the above embodiments, in Figure 2 , Figures 3A-3C The example shown is that the stack housing 30 and the VCU housing 40 constitute the housing 50, but the housing is only required to house the battery stack and is not limited to the example shown. For example, the VCU housing 40 may not be included.

[0047] The above description is merely an example, and the above embodiments and modifications do not limit the invention as long as they do not destroy its features. One or more of the above embodiments and modifications can be combined in any way, and modifications can also be combined with each other.

[0048] Explanation of reference numerals in the attached figures 1: Battery; 2: Integrated electrode assembly; 3: Separator; 10: Battery stack; 10a: Side surface; 11: Protrusion; 20: End unit; 21: End plate; 30: Stack shell; 31: Side wall; 31a: Inner surface; 32: Recess; 40: VCU shell; 41: Side wall; 50: Shell; 51: Connecting hole; 52-55: Opening; 60a-60d: Supporting member; 61, 62: End face; 63: Protrusion; 64: Recess; 70: Filter unit; 71: Cover; 72: Filter; 100: Fuel cell; 211-216: Through hole; EX: External space; h: Height difference; SP30-SP34, SP40: Space.

Claims

1. A fuel cell, characterized in that, have: A battery stack is formed by alternately stacking membrane electrode structures and separators, wherein the membrane electrode structures include an electrolyte membrane and electrodes; A housing that houses the battery stack; and Multiple rod-shaped members extend in the stacking direction such that they divide the cylindrical space formed between the side surface of the battery stack and the inner surface of the housing into multiple spaces in a manner substantially parallel to the stacking direction of the battery stack, and one end face is in close contact with or close to the inner surface of the housing, and the other end face is in close contact with or close to the side surface of the battery stack. The housing is provided with a plurality of openings that connect the plurality of spaces to the external space of the housing.

2. The fuel cell according to claim 1, characterized in that, The plurality of rod-shaped members serve as support members for the battery stack. The plurality of rod-shaped members includes a pair of first rod-shaped members and a pair of second rod-shaped members. The end face of the other end of the pair of first rod-shaped members is in close contact with or near a pair of inner surfaces of the shell facing each other in a first direction orthogonal to the stacking direction. The end face of the other end of the pair of second rod-shaped members is in close contact with or near a pair of inner surfaces of the housing facing each other in a second direction orthogonal to the stacking direction and the first direction.

3. The fuel cell according to claim 1 or 2, characterized in that, It also has multiple filters, which are respectively disposed in the multiple openings.

4. The fuel cell according to claim 1 or 2, characterized in that, The plurality of openings includes a pair of openings that connect a specific space within the plurality of spaces to the external space. The pair of openings are positioned at different heights in the direction of gravity.

5. The fuel cell according to claim 1 or 2, characterized in that, At least a portion of the plurality of openings are located in the upper part of the gravity direction of the space communicating with the external space.

Images