Leak detection device

Abstract

To provide a leak detection device that can improve energy efficiency by suppressing an increase in the number of work steps in a manufacturing process of a fuel cell stack.SOLUTION: A leak detection device 1, 61 includes a pressing device 15 that presses stacked fuel cell cells FC housed in a fuel cell case C with one end closed and the other end not closed by a lid, a supply device 61 that supplies gas to the fuel cell case C when the pressing force from the pressing device 15 is equal to or greater than a predetermined pressure, and a detection device 61 that detects gas leakage from the fuel cell case C when gas is being supplied by the supply device 61.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a leak detection device. [Background technology]

[0002] BACKGROUND ART Conventionally, in the manufacturing process of a fuel cell stack, a leak detection device is known that inspects for gas leaks after a plurality of stacked fuel cells are housed in a fuel cell case (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-077045 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above leak detection device, after stacked fuel cells are housed in a fuel cell case of a fuel cell stack, the fuel cell stack is fastened with a given load using a fastening device that fastens a lid to the opening of the fuel cell case, and then leak detection is performed.If a leak is detected by leak detection, the fuel cell stack with the lid fastened to the fuel cell case must be disassembled and the fuel cell must be replaced, which poses a problem of increasing the number of work steps in the fuel cell stack manufacturing process.

[0005] An object of the present invention is to provide a leak detection device that can improve energy efficiency by making it possible to suppress an increase in the number of work steps in the manufacturing process of a fuel cell stack. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a leak detection device (for example, the "case holding unit 1, pressure inspection device 61" described below) that detects leaks in a fuel cell case (for example, the "fuel cell case C" described below) that houses a plurality of stacked fuel cell cells (for example, the "fuel cell FC" described below), the leak detection device comprising: a pressing device (for example, the "pressure inspection device 15" described below) that presses the stacked fuel cell cells that are housed in the fuel cell case with one end closed and the other end not closed by a lid; a supply device (for example, the "pressure inspection device 61" described below) that supplies gas to the fuel cell case when the pressing force applied by the pressing device is equal to or greater than a predetermined pressure; and a detection device (for example, the "pressure inspection device 61" described below) that detects gas leakage from the fuel cell case when gas is being supplied by the supply device.

[0007] In the above invention, it is preferable to provide a one-end jig (for example, the "lower jig 20" described below) that is connected to one end of the fuel cell case and supplies gas through the fuel cell case. It is also preferable that the gas is supplied through a flow path for gas supplied when the fuel cell is in use. It is also preferable to provide an other-end jig (for example, the "upper jig 30" described below) that closes the other end side of the fuel cell case and has a seal structure that prevents the supplied gas from leaking from the fuel cell case. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a leak detection device that can improve energy efficiency by suppressing an increase in the number of work steps in the manufacturing process of a fuel cell stack. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a leak detection device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a top perspective view illustrating a lower jig of the leak detection device according to the embodiment. [Figure 3]FIG. 2 is a bottom perspective view illustrating a lower jig of the leak detection device according to the embodiment. [Figure 4] FIG. 2 is a top perspective view illustrating an upper jig of the leak detection device according to the embodiment. [Figure 5] FIG. 4 is a side view illustrating a bolt attached to an upper jig of the leak detection device in this embodiment. [Figure 6] 3A to 3C are diagrams illustrating the process of leak detection by the leak detection device according to the present embodiment. [Figure 7] 4 is a flowchart illustrating a leak detection process performed by the leak detection device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will now be described. As shown in Fig. 1, the leak detection device is a device that detects gas leaks in a fuel cell case C after fuel cells FC are housed in the fuel cell case C that constitutes a fuel cell stack and before a lid F is fastened to the fuel cell case C, and includes a case holding unit 1 and a pressure inspection device 61.

[0011] The case holding unit 1 includes a bottom 11, a top plate 12, support columns 13, an upper support 14, a pressing device 15, a lower jig 20 as one end jig, and an upper jig 30 as the other end jig. Also, one ends of pipe members 62, 63, and 64 are connected to a pressure testing device 61.

[0012] The bottom 11 is the lowest part of the case holding part 1 and supports the top plate 12, support columns 13, etc. that make up the case holding part 1. The top plate 12 is located vertically above the bottom 11 and is supported by multiple support columns 13 that extend upward from the bottom 11. An upper support part 14 is supported by the multiple support columns 13 so as to be movable up and down along the support columns 13 relative to the support columns 13.

[0013] A pressing device 15 is provided on the upper support portion 14. The pressing device 15 is electrically connected to a pressure inspection device 61 by an electrical line 65 such as a lead wire or wirelessly, and the pressure applied by the pressing device 15 to the stacked fuel cells FC as described below can be detected by the pressure inspection device 61.

[0014] An upper jig 30 is fixed to the lower end of the pressing device 15. A lower jig 20 is provided on the bottom 11 vertically below the upper jig 30. The bottom of the fuel cell case C is placed on the upper surface of the lower jig 20. The upper jig 30 is configured to airtightly seal the opening at the upper end of the fuel cell case C placed on the upper surface of the lower jig 20. Specifically, as shown in FIG. 5 , the upper jig 30 and the upper end of the fuel cell case C are connected by bolts 36 fitted with O-rings 362, creating a sealed structure in which the opening at the upper end of the fuel cell case C is airtightly sealed by the upper jig 30.

[0015] As shown in Figure 3, the lower jig 20 has a rectangular plate-shaped central base 21, a pair of pipe support portions 22 respectively connected to a pair of short sides of the rectangular central base 21, and a mounting portion 23 arranged over almost the entire upper surface of the central base 21 and on which the bottom of the fuel cell case C is placed.

[0016] The other ends of pipe members 62, 63, and 64 connected to the respective flow paths (hereinafter referred to as "flow paths of the fuel cell stack FCS") for hydrogen gas, air, and cooling water as a refrigerant supplied to the fuel cell stack FCS when the fuel cell stack FCS is in use (operating) are fixed to the pair of pipe supports 22 of the lower jig 20. Although the pipe members 62, 63, and 64 are shown as single pipe members in FIG. 1 for the sake of convenience, they are actually provided in pairs, one for the supply side and one for the discharge side. The supply side ends of the pipe members 62, 63, and 64 are fixed to one of the pair of pipe supports 22, and the discharge side ends of the pipe members 62, 63, and 64 are fixed to the other of the pair of pipe supports 22.

[0017] Helium gas for gas leak detection can be supplied to pipe members 62, 63, and 64 from pressure testing device 61. Helium gas can be circulated through the flow paths of fuel cell stack FCS in place of these gases and refrigerants.

[0018] A control device is provided inside the pressure inspection device 61. The control device provided inside the pressure inspection device 61 controls inputting the value of the pressure applied to the stacked fuel cells FC by the pressing device 15 via a line 65. The control device provided inside the pressure inspection device 61 also controls the supply and circulation of helium gas into the fuel cell case C via the pipe members 62, 63, 64, and the lower jig 20. The pressure inspection device 61 constitutes a supply device that supplies helium gas. The pressure inspection device 61 also constitutes a leak detection device that detects leaks of helium gas from the fuel cell case C by detecting the pressure of the supplied helium gas from the fuel cell case C while helium gas is being supplied.

[0019] Next, the process of detecting a leak using the leak detection device will be described with reference to Figures 6 and 7. In the leak detection process, first, in step S11 of Figure 7, a fuel cell case C containing a plurality of stacked fuel cells FC therein and with the opening at the top end open is placed on the top surface of the lower jig 20. Next, the other ends of the pipe members 62, 63, and 64 are each fixed to the lower jig 20 and connected to the flow paths of the fuel cell stack FCS.

[0020] Next, the upper support part 14 is slid relative to the support 13 to move the upper jig 30 downward, blocking the opening at the upper end of the fuel cell case C, and sealing the space between the fuel cell case C and the upper jig 30 to make it airtight so that the helium gas supplied from the pressure testing device 61 does not leak.

[0021] Next, in step S12 of Fig. 7, and as shown by "arbitrary load" in Fig. 6, the pressing device 15 applies an arbitrary load to the stacked fuel cell cells FC to pressurize (press), and as shown by "pressure inspection" in Fig. 6, when the pressing force applied by the pressing device 15 is equal to or greater than a predetermined pressure, a pressure inspection is performed to detect the pressure of the helium gas while helium gas is being supplied to the fuel cell case C from the pressure inspection device 61. The predetermined pressure is, for example, a pressure equivalent to the pressure applied to the stacked fuel cell cells FC in the manufactured fuel cell stack FCS.

[0022] If the pressure test results are normal and no leaks are detected (step S12: OK), in step S13 of Fig. 7 and as shown by "fastening" in Fig. 6, the upper jig 30 is removed from the fuel cell case C, and the opening at the top end of the fuel cell case C is closed with the lid F to make the gap between the fuel cell case C and the lid F airtight. Then, the process proceeds to step S15.

[0023] If a leak is detected as a result of the pressure test (step S12: NG), in step S14 of Figure 7, pressing is performed with an even higher load, or the stacking length of the stacked fuel cell cells FC is adjusted, and the process returns to step S12 again.

[0024] In step S15 of Figure 7, with the opening at the upper end of the fuel cell case C blocked by the lid F, helium gas is again supplied to the fuel cell case C from the pressure testing device 61 to perform a pressure test, and if the results are confirmed to be normal, in step S16 of Figure 7, an insulation test is performed between the insulating case and the metal parts of the fuel cell stack FCS.Then, in step S17 of Figure 7, an inspection is performed to check whether there are any abnormalities in the harness installation (C2C short circuit test), and in step S18 of Figure 7, the product is removed, completing the manufacturing process of the fuel cell stack FCS.

[0025] The effects of the above embodiment are as follows. In this embodiment, the leak detection device includes a pressing device 15 that presses stacked fuel cell cells FC housed in a fuel cell case C in a state where one end, i.e., the lower end, is closed and the other end, i.e., the upper end, is not closed by a lid F; a pressure inspection device 61 that serves as a supply device that supplies gas to the fuel cell case C when the pressing force from the pressing device 15 is equal to or greater than a predetermined pressure; and a pressure inspection device 61 that serves as a leak detection device that detects leakage of helium gas from the fuel cell case C when helium gas is being supplied by the pressure inspection device 61.

[0026] This makes it possible to determine whether the pressure test (pressure inspection) passes or fails before fastening the lid F to the fuel cell case C. This makes it possible to greatly reduce the amount of reassembly work required if the pressure inspection fails after the lid F is fastened to the fuel cell case C.

[0027] Furthermore, in this embodiment, the leak detection device is connected to the lower end as one end of the fuel cell case C and includes a lower jig 20 as an one end jig that supplies helium gas through the fuel cell case C. As a result, by supplying helium gas to the lower jig 20, it becomes possible to circulate the helium gas inside the fuel cell case C through the fuel cell case C. Therefore, there is no need to provide a separate structure for supplying and circulating helium gas inside the fuel cell case C, making pressure testing easier.

[0028] In this embodiment, helium gas is supplied through the same flow paths as hydrogen gas, air, and refrigerant that are supplied when the fuel cell stack FCS is in use. This makes it possible to perform pressure inspections on the flow paths that are actually used when the fuel cell stack FCS is in use. Furthermore, because pressure inspections are performed using helium gas atoms, which have a small diameter and do not explode, leak detection can be performed safely and with high accuracy.

[0029] In addition, in this embodiment, the leak detection device includes an upper jig 30 as an other end jig that closes the opening at the upper end, which is the other end side of the fuel cell case C, and has a seal structure that prevents the supplied helium gas from leaking from the fuel cell case C. This makes it possible to perform pressure inspection with the upper end closed by the seal structure, just like the fuel cell stack FCS. This makes it possible to perform pressure inspection with high accuracy.

[0030] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention. For example, the configurations of the pressing device, the supply device, the leak detection device, and the like of the present invention are not limited to the pressing device 15 and the pressure inspection device 61 in this embodiment. [Explanation of symbols]

[0031] 1 Case holder (leak detection device) 15 Pressing device 20 Lower jig (one end jig) 30 Upper jig (other end jig) 61 Pressure testing equipment (leak detection equipment, supply equipment, detection equipment) C. Fuel cell case FC fuel cell

Claims

1. A leak detection device for detecting leaks in a fuel cell case that houses a plurality of stacked fuel cells, a pressing device that presses the stacked fuel cell units housed in the fuel cell case with one end closed and the other end not closed by a lid; a supply device that supplies gas to the fuel cell case when the pressure applied by the pressing device is equal to or greater than a predetermined pressure; a detection device that detects gas leakage from the fuel cell case while the gas is being supplied by the supply device.

2. The leak detection device according to claim 1 , further comprising an end jig connected to one end of the fuel cell case and supplying gas through the fuel cell case.

3. 3. The leak detection device according to claim 2, wherein the gas is supplied through a gas flow path that is used when the fuel cell is in use.

4. 2. The leak detection device according to claim 1, further comprising an other end jig having a seal structure that closes the other end of the fuel cell case and prevents the supplied gas from leaking from the fuel cell case.

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