JP7647544B2 - Separator leak inspection device - Google Patents

Description

The technology disclosed in this specification relates to a leak inspection device for separators for fuel cells.

A fuel cell is composed of multiple fuel cell cells stacked together. Each fuel cell has a pair of separators (i.e., an anode separator and a cathode separator), a membrane electrode assembly (MEA), an anode gas diffusion layer, and a cathode gas diffusion layer.

The separators are provided with manifold holes for supplying or discharging fluids such as anode gas, cathode gas, and cooling medium. When multiple fuel cells are stacked, the manifold holes are connected in series to form a connecting flow path. In each fuel cell, the various fluids mentioned above are supplied from the connecting flow path or discharged to the connecting flow path. Each separator is provided with a gasket, for example, surrounding the manifold hole to prevent fluids from leaking from the connecting flow path.

Fuel cell separators are required to be free of pinholes. In this regard, Patent Document 1 describes an inspection device for fuel cell separators. This inspection device includes a light-projecting unit that irradiates light toward one side of the separator, and a light-receiving unit that detects the light that has passed through pinholes in the separator on the other side of the separator. With this configuration, it is possible to inspect the separator for the presence or absence of pinholes by light transmission.

JP 2019-087385 A

In recent years, the use of resin separators instead of conventional metal separators as separators for fuel cells has been considered. Resin separators may be made thicker in order to ensure the same performance as metal separators. As a result, when inspecting resin separators for pinholes by light transmission, there is a risk that the light will not be able to transmit through pinholes even if they exist in the separator due to their large thickness. As a result, there is a risk that the accuracy of pinhole detection will decrease.

In view of the above situation, this specification provides a technology for accurately detecting whether or not a pinhole is present in a separator.

The technology disclosed in this specification is embodied in a leak inspection device for a separator for a fuel cell. The separator has a manifold hole for supplying or discharging gas, and a plurality of grooves extending radially from the manifold hole. The leak inspection device includes a pair of jigs for clamping the separator, a rubber seal member provided on one of the pair of jigs and abutting against the separator to form a sealed space between the one of the pair of jigs and the separator, a gas supplier for supplying gas to the sealed space, and a pressure gauge for monitoring the pressure of the sealed space. The seal member is disposed along the periphery of the manifold hole and includes a seal portion for the manifold hole that abuts across the plurality of grooves. The seal portion for the manifold hole has a rectangular cross-sectional shape in an unloaded state, and its rubber hardness is 40 degrees to 80 degrees.

In the above leak inspection device, a seal member is provided on one of the pair of jigs. The seal member forms a sealed space between one of the pair of jigs and the separator by contacting the separator. In other words, the sealed space is defined by one of the pair of jigs, one surface of the separator, and the seal member. At this time, the seal portion for the manifold hole included in the seal member is arranged along the periphery of the manifold hole and needs to seal each of the multiple grooves extending radially from the manifold hole. In this regard, since the seal portion has a rectangular cross-sectional shape in the unloaded state, it can widely contact each of the multiple grooves and reliably seal the multiple grooves. As a result, the leak inspection device can supply gas to the sealed space and monitor the pressure of the sealed space to determine whether or not gas leakage is occurring from the sealed space. In other words, it can determine that a defect such as the presence of a pinhole in the separator has occurred. Unlike an inspection by light transmission, such a leak inspection can accurately detect whether or not a pinhole exists regardless of the thickness of the separator.

FIG. 2 is a diagram for explaining a separator 100. 1 is a diagram showing a schematic configuration of a leak inspection device 10. Here, a separator 100 is placed on a stage of a lower jig 16. FIG. 4 is a diagram for explaining a seal member 20. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1 is a diagram showing a schematic configuration of a leak inspection device 200 according to a second embodiment. Here, a separator 100 is placed on a stage of a lower jig 16. 1 is a diagram showing a schematic configuration of a leak inspection device 300 according to a third embodiment. Here, the separator 100 is placed on a stage of a lower jig 16.

In one embodiment of the present technology, the sealing member may be made of ethylene propylene diene rubber. However, the sealing member does not necessarily have to be made of ethylene propylene diene rubber. In other words, any rubber material with a rubber hardness of 40 degrees to 80 degrees can be used as the sealing member.

(Example 1) With reference to the drawings, the leak inspection device 10 of Example 1 will be described. The leak inspection device 10 of this example is a device for inspecting a separator 100 for a fuel cell. In particular, this leak inspection device 10 can detect the presence of defective parts such as pinholes in the separator 100. First, with reference to FIG. 1, the separator 100 to be inspected in this example will be described. Here, the case where the separator 100 is an anode side separator will be described. However, the separator 100 may also be a cathode side separator. As shown in FIG. 1, the separator 100 is a member having a plate shape. The separator 100 is made of a gas-impermeable conductive material, such as a substrate containing titanium or a substrate containing carbon.

As shown in FIG. 1, the separator 100 has six manifold holes 102a-102f. The six manifold holes 102a-102f include three supply holes 102a-102c and three discharge holes 102d-102f. The three supply holes 102a-102c are holes for supplying fluid to the power generation region PG. The three discharge holes 102d-102f are holes for discharging fluid that has passed through the power generation region PG. Each of the three supply holes 102a-102c and the three discharge holes 102d-102f is located at both ends of the separator 100 in the longitudinal direction. As an example, the first supply hole 102a is an anode gas supply hole, the first exhaust hole 102b is an anode gas exhaust hole, the second supply hole 102c is a cathode gas supply hole, the second exhaust hole 102d is a cathode gas exhaust hole, the third supply hole 102e is a cooling medium supply hole, and the third exhaust hole 102f is a cooling medium exhaust hole.

As shown in FIG. 1, the separator 100 further includes a flow path 104 and a plurality of grooves 106. The flow path 104 is provided in the center of the separator 100. In this embodiment, since the separator 100 is an anode-side separator, one surface of the separator 100 (hereinafter sometimes referred to as the "gas surface") is provided with a plurality of grooves 106 extending radially from the first supply hole 102a toward the flow path 104 through which the anode gas passes. In addition, the gas surface of the separator 100 is further provided with a plurality of grooves 106 extending radially from the first discharge hole 102b toward the flow path 104 through which the anode gas passes. As a result, the anode gas passes through the first supply hole 102a, the plurality of grooves 106, and the flow path 104 in order, and is then supplied to the power generation region PG, and then passes through the flow path 104 and the plurality of grooves 106 in order, and is then discharged to the first discharge hole 102b.

Although not particularly limited, the other surface (not shown) of the separator 100 may be provided with a plurality of grooves 106 extending radially from the third supply hole 102e toward the flow path 104 through which the cooling medium passes, and a plurality of grooves 106 extending radially from the third discharge hole 102f toward the flow path 104 through which the cooling medium passes. As a result, the cooling medium passes through the third supply hole 102e, the plurality of grooves 106, and the flow path 104 in this order to cool the power generation region PG, and then passes through the flow path 104 and the plurality of grooves 106 in this order to be discharged to the third discharge hole 102f.

Next, the leak inspection device 10 will be described with reference to FIG. 2. As shown in FIG. 2, the leak inspection device 10 includes a main frame 12 and a pair of jigs 14 and 16. The main frame 12 is a member for supporting components such as the pair of jigs 14 and 16. The pair of jigs 14 and 16 includes an upper jig 14 and a lower jig 16. The upper jig 14 and the lower jig 16 are arranged to face each other. The portion of the upper jig 14 facing the lower jig 16 and the portion of the lower jig 16 facing the upper jig 14 are both made of metal plates having a predetermined thickness. As a result, the portion of the lower jig 16 facing the upper jig 14 can function as a stage for placing the separator 100 to be inspected.

As shown in FIG. 2, the leak inspection device 10 further includes a press mechanism 18. The press mechanism 18 is an actuator such as a hydraulic cylinder or an air cylinder. For example, the press mechanism 18 is provided on the upper jig 14 and can move the upper jig 14 in the vertical direction. With the separator 100 to be inspected placed on the stage of the lower jig 16, the upper jig 14 can be moved downward using the press mechanism 18, thereby sandwiching the separator 100 between the upper jig 14 and the lower jig 16. At this time, the separator 100 is placed on the stage of the lower jig 16 so that the gas surface of the separator 100 faces downward.

As shown in FIG. 3, the leak inspection device 10 further includes a seal member 20. The seal member 20 is provided on the lower jig 16. The seal member 20 includes a plurality of seal portions 20a-20d for the manifold holes and an overall seal portion 20e. The plurality of seal portions 20a-20d for the manifold holes include a first seal portion 20a, a second seal portion 20b, a third seal portion 20c, and a fourth seal portion 20d. The first seal portion 20a is a seal portion corresponding to the first supply hole 102a, the second seal portion 20b is a seal portion corresponding to the first discharge hole 102b, the third seal portion 20c is a seal portion corresponding to the second supply hole 102c, and the fourth seal portion 20d is a seal portion corresponding to the second discharge hole 102d. When the separator 100 is clamped between the upper jig 14 and the lower jig 16, each of the multiple seal portions 20a-20d for the manifold holes is arranged along the periphery of the corresponding manifold hole 102a-102d. At this time, each of the first seal portion 20a and the second seal portion 20b can abut across the multiple grooves 106 formed radially from the corresponding manifold hole (i.e., each of the first supply hole 102a and the first discharge hole 102b).

The overall seal portion 20e is a seal portion that corresponds to the third supply hole 102e, the third exhaust hole 102f, and the power generation region PG. When the separator 100 is clamped between the upper jig 14 and the lower jig 16, the overall seal portion 20e can abut against the gas surface of the separator 100. As a result, the seal member 20 as a whole abuts against the separator 100, thereby forming an airtight space between the lower jig 16 and the separator 100.

As shown in FIG. 4, the seal member 20 has a rectangular cross-sectional shape in an unloaded state. As an example, a groove for placing the seal member 20 is formed in the lower jig 16, and the seal member 20 is placed so as to be accommodated in the groove. The thickness of the seal member 20 is, for example, 2 mm. The seal member 20 is made of a rubber material such as ethylene propylene diene rubber, and has a rubber hardness of 40 degrees to 80 degrees. Here, the rubber hardness means the hardness measured by a type A durometer in accordance with JIS K 6253. Note that the seal member 20 does not necessarily have to be made of ethylene propylene diene rubber. In other words, any rubber material having a rubber hardness of 40 degrees to 80 degrees can be used as the seal member 20.

Although not particularly limited, the upper jig 14 may also be provided with a sealing member 20, similar to the lower jig 16.

As shown in FIG. 2, the leak inspection device 10 further includes a gas supply 22 and a pressure measuring device 24. The gas supply 22 includes a gas supply source 22a and a valve 22b. The gas supply source 22a is connected to a gas supply path R provided on the lower jig 16 (and the main frame 12) and can supply gas to the sealed space described above. As an example, the gas supply source 22a includes a tank in which gas is stored and a compressor, and can supply gas pressurized to a predetermined pressure to the sealed space. The valve 22b is provided on the gas supply path R and can switch the supply state of gas from the gas supply source 22a to the sealed space. When the valve 22b is in an open state, gas is supplied from the gas supply source 22a to the sealed space, and when the valve 22b is in a closed state, the supply of gas from the gas supply source 22a to the sealed space is stopped. When the valve 22b is closed, the sealing member 20 and the valve 22b seal the sealed space formed between the lower jig 16 and the separator 100. Although not limited thereto, the gas supplied from the gas supply source 22a may be air, nitrogen, hydrogen, helium, or the like.

The pressure measuring instrument 24 is connected to the gas supply path R and is located between the sealed space and the gas supplier 22. Because the gas supply path R is connected to the sealed space described above, the pressure measuring instrument 24 can monitor the gas pressure in the sealed space. For example, if the pressure difference between the pressure when the gas supply from the gas supplier 22 is stopped and the pressure after a predetermined time has elapsed thereafter is within an allowable range, it can be determined that no gas leak is occurring from the sealed space. As one example, the pressure measuring instrument 24 is a differential pressure leak tester.

As described above, the leak inspection device 10 supplies gas to the sealed space and monitors the pressure in the sealed space, thereby making it possible to determine whether or not gas is leaking from the sealed space. In other words, it is possible to determine that a defect such as the presence of a pinhole in the separator 100 has occurred. Unlike inspections that use light transmission, this type of leak inspection can accurately detect whether or not a pinhole is present, regardless of the thickness of the separator 100.

In the leak inspection device 10 of this embodiment, a sealed space is formed between the lower jig 16 and the separator 100 by the seal member 20. At this time, the first seal portion 20a arranged along the periphery of the first supply hole 102a needs to seal the multiple grooves 106 extending radially from the first supply hole 102a. Similarly, the second seal portion 20b arranged along the periphery of the first discharge hole 102b needs to seal the multiple grooves 106 extending radially from the first discharge hole 102b. In this regard, since the first seal portion 20a and the second seal portion 20b have a rectangular cross-sectional shape in the unloaded state, they can widely abut against each of the multiple grooves 106, and can reliably seal the multiple grooves 106.

(Example 2) Next, a leak inspection device 200 of Example 2 will be described. In this example, the arrangement of each component of Example 1 is changed, and the functions of each component are common. Therefore, the common components are given the same reference numerals, and the duplicated description will be omitted here. As shown in FIG. 5, compared to the leak inspection device 10 of Example 1, in the leak inspection device 200 of this example, the seal member 20 is provided on the upper jig 14, and the seal member 20 of the upper jig 14 abuts against the separator 100, so that an enclosed space is formed between the upper jig 14 and the separator 100. In detail, in the leak inspection device 200, instead of the lower jig 16, the seal member 20, the gas supply device 22, and the pressure measuring device 24 are provided on the upper jig 14. In addition, in the leak inspection device 200, instead of the upper jig 14, the press mechanism 18 is provided on the lower jig 16. With the separator 100 to be inspected placed on the stage of the lower jig 16, the lower jig 16 can be moved upward using the press mechanism 18, so that the separator 100 can be sandwiched between the upper jig 14 and the lower jig 16. In this way, the seal member 20 as a whole abuts against the separator 100, forming an airtight space between the upper jig 14 and the separator 100. Note that in the leak inspection device 200 of Example 2, unlike the leak inspection device 10 of Example 1, the separator 100 is placed on the stage of the lower jig 16 so that the gas surface of the separator 100 is on the upper side.

Although not particularly limited, the leak inspection device 10 may further include a tilt prevention guide (not shown). By providing the tilt prevention guide on the lower jig 16, it is possible to prevent the separator 100 arranged on the stage of the lower jig 16 from tilting when the lower jig 16 is moved up and down by the press mechanism 18. In another embodiment, the leak inspection device 200 of this embodiment may be provided with press mechanisms 18 on both the upper jig 14 and the lower jig 16.

With the above configuration, it is possible to determine whether gas is leaking from the sealed space by supplying gas to the sealed space and monitoring the pressure in the sealed space. In other words, it is possible to determine whether a defect such as a pinhole exists in the separator 100.

(Example 3) Next, a leak inspection device 300 of Example 3 will be described. In this example, instead of the press mechanism 18 of Examples 1 and 2, an operator or the like clamps the separator 100 using the upper jig 14 and the lower jig 16. Therefore, in the leak inspection device 300, compared to Example 1, instead of the upper jig 14 being moved in the vertical direction by the press mechanism 18, the upper jig 14 is moved in the vertical direction by an operator or the like. In detail, the leak inspection device 300 further includes a handle 26, a guide pin 28, and a guide hole 30 instead of the press mechanism 18. Note that other common components are given the same reference numerals, and redundant explanations will be omitted here. The handle 26 is provided on the upper jig 14. An operator or the like can easily move the upper jig 14 by holding the handle 26. As an example, the guide pin 28 is provided in the lower jig 16, and the guide hole 30 is provided in the upper jig 14. By inserting the guide pin 28 into the guide hole 30, an operator can move the upper jig 14 in the vertical direction without tilting it. Although not shown, the upper jig 14 can be fixed to the lower jig 16 using bolts, washers, nuts, etc., so that the separator 100 can be sandwiched between the upper jig 14 and the lower jig 16, as in Examples 1 and 2.

With the above configuration, it is possible to determine whether gas is leaking from the sealed space by supplying gas to the sealed space and monitoring the pressure in the sealed space. In other words, it is possible to determine whether a defect such as a pinhole exists in the separator 100.

Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above. The technical elements described in this specification or drawings exhibit technical usefulness either alone or in combination.

Reference Signs List 10, 200, 300: Leak inspection device 12: Main frame 14: Upper jig 16: Lower jig 18: Press mechanism 20: Sealing members 20a-20d: Sealing section 20e: Overall sealing section 22: Gas supplier 22a: Gas supply source 22b: Valve 24: Pressure measuring device 26: Handle 28: Guide pin 30: Guide hole 100: Separators 102a-102f: Manifold hole 104: Flow path 106: Groove PG: Power generation region R: Gas supply path

Claims (2)

A leak inspection device for a separator for a fuel cell, the device comprising: a manifold hole for supplying or discharging gas; and a plurality of grooves extending radially from the manifold hole,
A pair of jigs that sandwich the separator;
a rubber seal member provided on one of the pair of jigs and abutting against one surface of the separator in a thickness direction of the separator to form an enclosed space between the one of the pair of jigs and the one surface of the separator;
A gas supplier for supplying gas to the sealed space;
A pressure measuring device for monitoring the pressure in the sealed space;
Equipped with
the seal member is disposed on the one surface of the separator so as to surround a periphery of the manifold hole and includes a seal portion for the manifold hole that abuts across the plurality of grooves,
The manifold hole seal portion has a rectangular cross-sectional shape in an unloaded state, and its rubber hardness is 40 degrees to 80 degrees.
Leak testing equipment. The leak inspection device according to claim 1, wherein the sealing member is made of ethylene propylene diene rubber.

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