Case for fuel cell

Abstract

To provide a case for a fuel cell which ensures ventilation and explosion-proof performance while suppressing the radiation and intrusion of electromagnetic waves.SOLUTION: A case for a fuel cell 10 houses a fuel cell inside, and includes a housing 2 formed of a conductive material and having a ventilation opening 1, and a gas permeable membrane 3 and a metal mesh 4 fixed to the housing 2 so as to cover the ventilation opening 1, and electrical conductivity is ensured between the metal mesh 4 and the housing 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell case that houses a fuel cell therein. [Background technology]

[0002] Patent Document 1 discloses a fuel cell case including a housing having a through-hole for ventilation, a ventilation membrane covering the through-hole, and a louver disposed on the outside of the ventilation membrane.

[0003] Patent Document 2 discloses a fuel cell case including a housing having a ventilation opening, a gas-permeable membrane covering the ventilation opening, and a metal plate member having a plurality of through holes formed in the metal plate member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-129166 A [Patent Document 2] JP 2011-129333 A Summary of the Invention [Problem to be solved by the invention]

[0005] Fuel cell vehicles, which run on an electric motor powered by electricity generated by a chemical reaction between hydrogen and oxygen in a fuel cell, are equipped with a fuel cell case that houses the fuel cell in order to prevent rainwater from entering the fuel cell. Such fuel cell cases are provided with ventilation openings to prevent an increase in hydrogen concentration inside the fuel cell case due to permeation of hydrogen gas from the fuel cell stack, and a gas permeable membrane is fixed to cover the ventilation openings. In such conventional fuel cell cases, the gas permeable membrane is fixed to cover the ventilation openings of the fuel cell case, thereby preventing the intrusion of rainwater while ensuring ventilation performance and explosion-proof performance.

[0006] However, the gas-permeable membrane is made of resin, and electromagnetic waves can pass through the gas-permeable membrane completely, so that electromagnetic waves can enter and exit through the ventilation opening without resistance. In addition, the fuel cell case disclosed in Patent Document 2 is equipped with a metal plate member covering the ventilation opening, but the through-hole formed in the metal plate member is large, so that high-frequency electromagnetic waves pass through the through-hole. In recent years, due to the need for space saving and cost reduction, not only a fuel cell stack but also electronic devices such as a DC (Direct Current)-DC converter and an inverter are installed inside the fuel cell case, and the emission of high-frequency electromagnetic waves is intensified due to high switching associated with high output and miniaturization. For this reason, the fuel cell case needs to ensure EMC (Electro-Magnetic Compatibility) performance and suppress the emission and intrusion of electromagnetic waves.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a fuel cell case that can suppress the radiation and intrusion of electromagnetic waves while ensuring ventilation performance and explosion-proof performance. [Means for solving the problem]

[0008] The fuel cell case of the present invention is a fuel cell case that houses a fuel cell inside, and is characterized in that it comprises a housing formed of a conductive material and having a ventilation opening, and a gas-permeable membrane and a metal mesh fixed to the housing so as to cover the ventilation opening, and electrical conductivity is ensured between the metal mesh and the housing. Effect of the Invention

[0009] The present invention can suppress the radiation and intrusion of electromagnetic waves while ensuring ventilation performance and explosion-proof performance. [Brief description of the drawings]

[0010] [Figure 1] 2 is a cross-sectional view of the vicinity of a through hole of the fuel cell casing of the first embodiment. FIG. [Diagram 2] 6 is a cross-sectional view of the vicinity of a through hole of a fuel cell case according to a second embodiment. FIG. [Diagram 3] 11 is a cross-sectional view of the vicinity of a through hole of a fuel cell case according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <First embodiment> Hereinafter, a fuel cell case 10 according to a first embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view of the vicinity of a ventilation opening 1 of the fuel cell case 10. The fuel cell case 10 is mounted on a fuel cell vehicle and houses electronic devices such as a fuel cell stack and a converter (not shown) therein. As shown in FIG. 1, the fuel cell case 10 includes a housing 2 having the ventilation opening 1, a gas permeable membrane 3 and a metal mesh 4 fixed to the housing 2 so as to cover the ventilation opening 1, and a holding frame 5. The housing 2 is formed of a conductive material such as aluminum.

[0012] The gas permeable membranes 3 are made of a polymeric resin. The gas permeable membranes 3 are arranged on the front and back sides of the metal mesh 4, and are pressure-molded to sandwich the metal mesh 4 from both sides. By pressure-molding in this manner, the two gas permeable membranes 3 and one metal mesh 4 are integrated to form a sandwich-structured pressure-molded plate 6 in which the gas permeable membranes 3 sandwich the metal mesh 4.

[0013] The housing 2 is provided with a contact surface 21 that contacts the pressure-bonded molded plate 6 on the outside. The housing 2 is provided with a pin 22 that protrudes from the contact surface 21. The pin 22 is made of a conductive material and has a pointed tip. When the pressure-bonded molded plate 6 is brought into contact with the contact surface 21 of the housing 2 when the pressure-bonded molded plate 6 is fixed to the housing 2, the pin 22 penetrates the pressure-bonded molded plate 6 and penetrates the gas permeable membrane 3 on one side to reach the metal mesh 4. The pin 22 penetrates the gas permeable membrane 3 and reaches the metal mesh 4 in this way, thereby ensuring conduction between the housing 2 and the metal mesh 4. The holding frame 5 is fixed to the housing 2 with the pressure-bonded molded plate 6 in contact with the contact surface 21 of the housing 2 in this way. When the holding frame 5 is fixed to the housing 2, the pressure-bonded molded plate 6 is sandwiched between the contact surface 21 and the holding frame 5 and is fixed to the housing 2 in a state where it covers the ventilation opening 1. Since the holding frame 5 has the recesses 51 formed therein, even if the pins 22 penetrate the compression molded plate 6, the pins 22 can be prevented from interfering with the holding frame 5.

[0014] The pressure-bonded molded plate 6 fixed to the housing 2 in this manner covers the ventilation opening 1, but gas can pass through the gas permeable membrane 3 and the metal mesh 4. Therefore, even if hydrogen gas leaks inside the fuel cell case 10, the hydrogen gas can be discharged from the ventilation opening 1, preventing an increase in the hydrogen gas concentration. Because hydrogen gas can be discharged from the ventilation opening 1 in this manner, the fuel cell case 10 can ensure ventilation performance and explosion-proof performance.

[0015] Electromagnetic waves entering or exiting through the ventilation opening 1 hit the metal mesh 4, are converted into weak noise currents, and are absorbed. The noise currents absorbed by the metal mesh 4 flow to the housing 2 via the pins 22, and flow out from the housing 2 to the ground via the ground wire. Therefore, the fuel cell case 10 can suppress the radiation and intrusion of electromagnetic waves. The mesh size of the metal mesh 4 is 3 millimeters or less. Since the main frequency of electromagnetic waves emitted by electronic devices housed in the fuel cell case 10 is 100 MHz or less, 3 millimeters corresponds to 1 / 1000 or less of the wavelength of the electromagnetic waves. Therefore, by making the mesh size of the metal mesh 4 3 millimeters or less, it is possible to prevent the transmission of electromagnetic waves emitted by electronic devices in the fuel cell case 10.

[0016] In this way, the fuel cell case 10 can suppress the radiation and intrusion of electromagnetic waves while ensuring ventilation performance and explosion-proof performance. Furthermore, in the fuel cell case 10, the metal mesh 4 is covered on both the front and back sides with the resin gas permeable membrane 3, so that the metal mesh 4 is less likely to deteriorate due to moisture or dirt. Therefore, the fuel cell case 10 can increase the durability of the metal mesh 4.

[0017] <Second embodiment> Next, a fuel cell case 20 according to a second embodiment will be described with reference to FIG. 2. FIG. 2 is a cross-sectional view of the vicinity of the ventilation opening 1 of the fuel cell case 20. The fuel cell case 20 is mounted on a fuel cell vehicle and houses electronic devices such as a fuel cell stack and a converter (not shown) therein. As shown in FIG. 2, the fuel cell case 20 includes a housing 2a having the ventilation opening 1, a gas permeable membrane 3 and a metal mesh 4 fixed to the housing 2a so as to cover the ventilation opening 1, a holding frame 5a, and a conductive sheet 7. The housing 2a is formed of a conductive material such as aluminum.

[0018] The conductive sheet 7 is disposed so as to be in contact with a contact surface 21 provided on the outside of the housing 2a. The metal mesh 4 is disposed so as to be in contact with the conductive sheet 7 and cover the ventilation opening 1. The gas permeable membrane 3 is disposed so as to be overlaid on the metal mesh 4 and cover the ventilation opening 1. Then, the gas permeable membrane 3, the metal mesh 4, and the conductive sheet 7 are overlaid on the contact surface 21 of the housing 2a, and the holding frame 5a is fixed to the housing 2a, whereby the gas permeable membrane 3, the metal mesh 4, and the conductive sheet 7 are sandwiched between the contact surface 21 and the holding frame 5a and fixed to the housing 2a.

[0019] Even when the gas permeable membrane 3 and metal mesh 4 are fixed to the housing 2a so as to cover the ventilation opening 1 in this way, gas can pass through the gas permeable membrane 3 and metal mesh 4. Therefore, even if hydrogen gas leaks inside the fuel cell case 20, the hydrogen gas can be discharged from the ventilation opening 1, preventing an increase in the hydrogen gas concentration. Because hydrogen gas can be discharged from the ventilation opening 1 in this way, the fuel cell case 20 can ensure ventilation performance and explosion-proof performance.

[0020] The metal mesh 4 contacts the contact surface 21 of the housing 2a via the conductive sheet 7, so that conduction between the housing 2a and the metal mesh 4 is ensured. The electromagnetic waves entering or exiting through the ventilation opening 1 hit the metal mesh 4, are converted into a weak noise current, and are absorbed. The noise current absorbed by the metal mesh 4 flows to the housing 2a via the conductive sheet 7, and flows out from the housing 2a to the earth via the earth wire. Therefore, the fuel cell case 20 can suppress the radiation and intrusion of electromagnetic waves. The mesh size of the metal mesh 4 is 3 millimeters or less. Since the main frequency of the electromagnetic waves emitted by the electronic device housed in the fuel cell case 20 is 100 MHz or less, 3 millimeters corresponds to 1 / 1000 or less of the wavelength of the electromagnetic waves. Therefore, by making the mesh size of the metal mesh 4 3 millimeters or less, the transmission of the electromagnetic waves emitted by the electronic device in the fuel cell case 20 can be prevented.

[0021] In this way, the fuel cell case 20 can suppress the radiation and intrusion of electromagnetic waves while ensuring ventilation performance and explosion-proof performance. Moreover, unlike the fuel cell case 10 of the first embodiment, the fuel cell case 20 does not form the pressure-bonded molded plate 6 and is not provided with the pins 22, so that the cost can be reduced compared to the fuel cell case 10 of the first embodiment. Note that, instead of using the conductive sheet 7, the fuel cell case 20 may have the metal mesh 4 adhered to the contact surface 21 of the housing 2a with a conductive adhesive.

[0022] <Third embodiment> Next, a fuel cell case 30 according to a third embodiment will be described with reference to FIG. 3. FIG. 3 is a cross-sectional view of the vicinity of the ventilation opening 1 of the fuel cell case 30. The fuel cell case 30 is mounted on a fuel cell vehicle and houses electronic devices such as a fuel cell stack and a converter (not shown) therein. As shown in FIG. 3, the fuel cell case 30 includes a housing 2b having the ventilation opening 1, a gas permeable membrane 3 and a metal mesh 4 fixed to the housing 2b so as to cover the ventilation opening 1, a holding frame 5b, and an earth bolt 8. The housing 2b is formed of a conductive material such as aluminum.

[0023] The gas permeable membrane 3 is disposed so as to cover the ventilation opening 1 while in contact with a contact surface 21 provided on the outside of the housing 2b. The holding frame 5b is disposed so as to sandwich the gas permeable membrane 3 between the contact surface 21 and the holding frame 5b. The metal mesh 4 is disposed so as to cover the ventilation opening 1 by sandwiching the holding frame 5b between the gas permeable membrane 3 and the metal mesh 4. Then, the gas permeable membrane 3, the holding frame 5b, and the metal mesh 4 are superimposed on the contact surface 21 of the housing 2b, and the earth bolt 8 is fastened to the housing 2b, thereby fixing the gas permeable membrane 3, the holding frame 5b, and the metal mesh 4 to the housing 2b.

[0024] Even when the gas permeable membrane 3 and metal mesh 4 are fixed to the housing 2b so as to cover the ventilation opening 1 in this way, gas can pass through the gas permeable membrane 3 and the metal mesh 4. Therefore, even if hydrogen gas leaks inside the fuel cell case 30, the hydrogen gas can be discharged from the ventilation opening 1, preventing an increase in the hydrogen gas concentration. Because hydrogen gas can be discharged from the ventilation opening 1 in this way, the fuel cell case 30 can ensure ventilation performance and explosion-proof performance.

[0025] The metal mesh 4 contacts the housing 2b via the earth bolt 8, so that conduction between the housing 2b and the metal mesh 4 is ensured. The electromagnetic waves entering or exiting through the ventilation opening 1 hit the metal mesh 4, are converted into a weak noise current, and are absorbed. The noise current absorbed by the metal mesh 4 flows to the housing 2b via the earth bolt 8, and flows out from the housing 2b to the earth via the earth wire. Therefore, the fuel cell case 30 can suppress the radiation and intrusion of electromagnetic waves. The mesh size of the metal mesh 4 is 3 millimeters or less. Since the main frequency of the electromagnetic waves emitted by the electronic devices housed in the fuel cell case 30 is 100 MHz or less, 3 millimeters corresponds to 1 / 1000 or less of the wavelength of the electromagnetic waves. Therefore, by making the mesh size of the metal mesh 4 3 millimeters or less, the transmission of the electromagnetic waves emitted by the electronic devices in the fuel cell case 30 can be prevented.

[0026] In this way, the fuel cell case 30 can suppress the radiation and intrusion of electromagnetic waves while ensuring ventilation performance and explosion-proof performance. Furthermore, the fuel cell case 30 allows the metal mesh 4 and the gas permeable membrane 3 to be replaced by removing the earth bolt 8. Therefore, when the metal mesh 4 and the gas permeable membrane 3 of the fuel cell case 30 deteriorate, the metal mesh 4 and the gas permeable membrane 3 can be replaced in a simple manner. Furthermore, unlike the fuel cell case 10 of the first embodiment, the fuel cell case 30 does not form the pressure-bonded molded plate 6 and is not provided with the pin 22, so that the cost can be reduced compared to the fuel cell case 10 of the first embodiment. [Explanation of symbols]

[0027] 1 ventilation opening, 2, 2a, 2b housing, 3 gas permeable membrane, 4 metal mesh, 5, 5a, 5b holding frame, 6 crimped molded plate, 7 conductive sheet, 8 earth bolt, 10, 20, 30 fuel cell case, 21 contact surface, 22 pin, 51 recess.

Claims

[Claim 1] A fuel cell case that houses a fuel cell therein, a housing formed of a conductive material and having a ventilation opening; a gas permeable membrane and a metal mesh fixed to the housing so as to cover the ventilation opening, A fuel cell case, characterized in that electrical continuity is ensured between the metal mesh and the housing.

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