A fuel cell bipolar plate leakage batch detection tool and method

Abstract

The present application relates to a kind of fuel cell bipolar plate leakage batch detection tool and method, the tool includes upper end plate (8), lower end plate (12), pull rod (13), multiple bipolar plate (10) is stacked between upper end plate (8) and lower end plate (12), and is fixed by pull rod (13), adjacent bipolar plate (10) and the sealing between bipolar plate (10) and upper end plate (8) and lower end plate (12) is sealed by sealing element (11), the upper end plate (8) and lower end plate (12) are equipped with fluorescent color developing agent solution inlet (5) and fluorescent color developing agent solution outlet (7), and hot air inlet (6) and hot air outlet (9). Compared with prior art, the present application can batch efficiently detect the air tightness of polar plate by a certain time of fluorescent agent tracer penetration multiple stacked polar plate, accurately locate leak point and semi-quantitative leakage condition, shorten detection beat, greatly improve polar plate screening efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to fuel cell, especially to a fuel cell bipolar plate leakage batch detection tool and method. BACKGROUND

[0002] With the fuel cell technology matures, as a zero pollution, high efficiency, can be directly converted into chemical energy to electrical power generation equipment has been more and more applied in communication base station, vehicle power, distributed power supply and other fields.

[0003] Bipolar plate is one of the core components of fuel cell, play a distribution of gas, heat and electrical energy. Because of the rated working condition, the voltage value of fuel cell single low, in order to achieve high power output, generally need more than one hundred or even hundreds of single cell to achieve. Thus the bipolar plate quality consistency control requirements are very high.

[0004] In order to improve the power density of fuel cell stack, and reduce the resistance. The thickness of fuel cell bipolar plate is required to be thinner and thinner, which puts forward strict anti leakage index requirements for both metal plate and graphite plate.

[0005] Usually in order to improve the bipolar plate leakage detection beat, the bipolar plate is stacked in water, the bipolar plate cooling cavity has a certain pressure gas, so as to directly observe the bubble situation of bipolar plate in water to realize, although the problem of bipolar plate can be quickly screened out, but the detection method still has the following several shortcomings:

[0006] 1, can not locate the leakage position on each bipolar plate;

[0007] 2, can not directly determine the leakage severity of each bipolar plate on the leakage point.

[0008] 3, the bipolar plate end detection after assembled into the true stack, the method seriously occupies the equipment resources, from the mass production is very undesirable. SUMMARY

[0009] The purpose of the present application is to overcome the defects of the prior art, and provide a fuel cell bipolar plate leakage batch detection tool and method which can locate the leakage position and batch detect. The method can realize a detection before the plate is made, screen out qualified bipolar plates for end-of-line stacking integration, effectively improve the success rate of one-time stacking, and realize the batch production of the stack.

[0010] The objective of this invention can be achieved through the following technical solution: a batch detection fixture for fuel cell bipolar plate leakage, wherein the bipolar plate includes a cooling fluid inlet, an air inlet, a cooling fluid outlet, and an air outlet, as well as a cooling fluid channel connecting the cooling fluid inlet and the cooling fluid outlet, and an air flow channel connecting the air inlet and the air outlet. The fixture is characterized in that it includes an upper end plate, a lower end plate, and a pull rod; multiple bipolar plates are stacked between the upper and lower end plates and fixed by the pull rod; adjacent bipolar plates and the bipolar plates are sealed to the upper and lower end plates by sealing elements; the upper and lower end plates are provided with a fluorescent colorimetric reagent solution inlet and a fluorescent colorimetric reagent solution outlet, as well as a hot air inlet and a hot air outlet; wherein the fluorescent colorimetric reagent solution inlet is connected to the cooling fluid inlet of the bipolar plate, the fluorescent colorimetric reagent solution outlet is connected to the cooling fluid outlet of the bipolar plate, the hot air inlet is connected to the air inlet of the bipolar plate, and the hot air outlet is connected to the air outlet of the bipolar plate.

[0011] The fluorescent colorimetric reagent solution inlet and outlet are connected to the fluorescent colorimetric reagent solution storage tank through a circulation pipeline, and a pump and heater are provided on the circulation pipeline.

[0012] The fluorescent colorimetric reagent solution storage tank contains a water-soluble fluorescent agent with a concentration of 200-2000 ppm.

[0013] The water-soluble fluorescent agents include stilbene derivatives, phenylpyrazoline derivatives, benzimidazole derivatives, benzoxazole derivatives, coumarin derivatives, and naphthalene dicarboximide derivatives or disodium salts of oxanthracene rings.

[0014] The water-soluble fluorescent agent exhibits fluorescence under ultraviolet light in the range of 365 nm to 405 nm.

[0015] The hot air inlet is connected to an air compressor via a pipe, and an air heater is installed on the pipe.

[0016] The temperature of the hot air introduced into the tooling through the hot air inlet is 40-80℃.

[0017] The number of bipolar plates stacked between the upper and lower end plates is 2-200.

[0018] The method for detecting fuel cell bipolar plate leakage using the aforementioned batch testing fixture includes the following steps:

[0019] Step 1: Stack bipolar plates between the upper and lower end plates, separating each bipolar plate with a seal;

[0020] Step 2: Use deionized water or antifreeze as solvent and water-soluble fluorescent agent as solute to prepare a fluorescent colorimetric solution with a concentration of 200-2000 ppm;

[0021] Step 3: Heat the prepared fluorescent color developer solution to 40-80℃, pump it into the tooling, and let it flow from the fluorescent color developer solution inlet into the cooling fluid inlet of each bipolar plate, through the cooling fluid channel, and from the cooling fluid outlet to the fluorescent color developer solution outlet, so that the fluid pressure in the cooling fluid channel is maintained at 20-200kPa and the flow rate is 0.1-1m / s, and let it stand for 1-7 days; at the same time, introduce hot air at 40-80℃ through the hot air inlet, let it flow through the air channel of the bipolar plate, and discharge it from the hot air outlet;

[0022] Step 4: After the settling period, extract the fluorescent colorimetric solution from the fixture, open the fixture, and disassemble the bipolar plates (10) one by one.

[0023] Step 5: Place the bipolar plates after testing into a dark room and check for leakage under ultraviolet light.

[0024] The area on the bipolar plate where fluorescence occurs is the leak point. The degree of leakage can be semi-quantitatively determined based on the size of the area where fluorescence occurs.

[0025] Compared with existing technologies, this invention utilizes a fluorescent colorimetric reagent to achieve efficient leakage detection on multiple stacked bipolar plates, simultaneously enabling precise location of leaks and semi-quantitative leakage assessment of a batch of bipolar plates. Specifically, a pre-prepared, heated liquid colorimetric reagent is pumped into the multi-stacked plate detection device. For a certain period, high pressure is maintained within the plate cooling chamber, and hot air is circulated from one side of the main current field of the plates. The introduction of hot air ensures that the moisture in the leaking fluorescent reagent evaporates quickly, preventing the leakage flow and diffusion from misleading the determination of the leak location and amount. After maintaining this pressure for a sufficient time, the colorimetric reagent solution is pumped out, and the cooling chamber is purged. The multi-stacked plate device is then opened, the plates are removed, and placed in a dark room. Ultraviolet light is used to observe the color development on both sides of the plates, allowing for a direct and accurate view of the leakage degree and location of each bipolar plate.

[0026] This invention uses fluorescent tracer to permeate multiple stacked electrode plates for a certain period of time, which can efficiently detect the airtightness of electrode plates in batches, accurately locate leaks and semi-quantitative leakage, shorten the detection cycle, greatly improve the electrode plate screening efficiency, and add an extra process at the front end of plate manufacturing to screen qualified bipolar plates, so as to ensure the one-time pass rate of the final stack. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a bipolar plate.

[0028] Figure 2 This is a schematic diagram of the batch detection fixture for bipolar plate leakage in fuel cells according to the present invention.

[0029] Figure 3This is a cross-sectional view of the batch testing fixture for bipolar plate leakage in the fuel cell of the present invention. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] A batch testing fixture for fuel cell bipolar plate leakage, the bipolar plate structure is as follows: Figure 1 As shown, it includes three inlets and three outlets and various fluid channels. During the testing of this application, the following are required: cooling fluid inlet 1, air inlet 2, cooling fluid outlet 3 and air outlet 4, as well as the cooling fluid channel connecting cooling fluid inlet 1 and cooling fluid outlet 3, and the air channel connecting air inlet 2 and air outlet 4.

[0033] like Figures 2-3 As shown, the tooling includes an upper end plate 8, a lower end plate 12, and a pull rod 13. Multiple bipolar plates 10 are stacked between the upper end plate 8 and the lower end plate 12 and fixed by the pull rod 13. Adjacent bipolar plates 10 and the bipolar plates 10 are sealed with seals 11. The upper end plate 8 and the lower end plate 12 are provided with a fluorescent colorimetric reagent solution inlet 5 and a fluorescent colorimetric reagent solution outlet 7, as well as a hot air inlet 6 and a hot air outlet 9. The fluorescent colorimetric reagent solution inlet 5 is connected to the cooling fluid inlet 1 of the bipolar plate 10, the fluorescent colorimetric reagent solution outlet 7 is connected to the cooling fluid outlet 3 of the bipolar plate 10, the hot air inlet 6 is connected to the air inlet 2 of the bipolar plate 10, and the hot air outlet 9 is connected to the air outlet 4 of the bipolar plate 10.

[0034] The fluorescent colorimetric reagent solution inlet 5 and outlet 7 are connected to the fluorescent colorimetric reagent solution storage tank via a circulation pipeline, and a pump and heater are installed on the circulation pipeline. The fluorescent colorimetric reagent solution storage tank contains a water-soluble fluorescent agent with a concentration of 200-2000 ppm. The water-soluble fluorescent agent includes stilbene derivatives, phenylpyrazoline derivatives, benzimidazole derivatives, benzoxazole derivatives, coumarin derivatives, and naphthalenedicarboximide derivatives or disodium ketones of xanthene rings. In this embodiment, the water-soluble fluorescent agent selected is a commercially available stilbene derivative containing 1000 ppm, which exhibits fluorescence under ultraviolet light (365 nm to 405 nm).

[0035] The hot air inlet 6 is connected to an air compressor via a pipe, and an air heater is installed on the pipe.

[0036] The method for detecting fuel cell bipolar plate leakage using the aforementioned batch testing fixture includes the following steps:

[0037] Step 1: Stack multiple bipolar plates 10 (8 bipolar plates are used as an example in this embodiment) between the upper end plate 8 and the lower end plate 12. Each bipolar plate 10 is separated by a sealing member 11 and fixed by a pull rod 13.

[0038] Step 2: Use deionized water or antifreeze as solvent and commercially available stilbene derivatives as solute to prepare a fluorescent colorimetric reagent solution with a concentration of 1000 ppm.

[0039] Step 3: The prepared fluorescent colorimetric reagent solution is placed in the fluorescent colorimetric reagent solution storage tank, pumped into the heater, heated to 60°C, pumped into the tooling, and flows from the fluorescent colorimetric reagent solution inlet 5 into the cooling fluid inlet 1 of each bipolar plate, flows through the cooling fluid channel, and flows from the cooling fluid outlet 3 to the fluorescent colorimetric reagent solution outlet 7, so that the fluid pressure in the cooling fluid channel is maintained at 100 kPa and the flow rate is 0.5 m / s, and left to stand for 5 days; at the same time, the air compressor inputs air into the heater, heats it to 60°C, inputs hot air inlet 6 into the air inlet 2 of the bipolar plate 10, flows through the air channel of the bipolar plate, flows out from the air outlet 4, and then is discharged through the hot air outlet 9;

[0040] Step 4: After the settling period, extract the fluorescent colorimetric solution from the fixture, open the fixture, and disassemble the bipolar plates 10 one by one.

[0041] Step 5: Place the bipolar plates after testing in a dark room and check the leakage of each bipolar plate under ultraviolet light. The area on the bipolar plate that shows a fluorescent reaction is the leakage point area. The degree of leakage is semi-quantitatively determined based on the size of the fluorescent reaction area.

[0042] Example 2

[0043] The water-soluble fluorescent agent used in this embodiment is a commercially available phenylpyrazoline derivative containing 200 ppm.

[0044] Two bipolar plates 10 are stacked between the upper end plate 8 and the lower end plate 12. The temperature of the fluorescent colorimetric reagent solution and the hot air pumped into the tooling is 40°C. The fluid pressure in the cooling fluid channel is maintained at 100 kPa and the flow rate is 0.4 m / s. The plate is left to stand for 7 days. The rest is the same as in Example 1.

[0045] Example 3

[0046] The water-soluble fluorescent agent used in this embodiment is a commercially available coumarin derivative containing 2000 ppm.

[0047] 200 bipolar plates 10 are stacked between the upper end plate 8 and the lower end plate 12. The temperature of the fluorescent colorimetric reagent solution and the hot air pumped into the tooling is 60°C. The fluid pressure in the cooling fluid channel is maintained at 200 kPa and the flow rate is 1 m / s. The plate is left to stand for 1 day. The rest is the same as in Example 1.

Claims

1. A batch testing fixture for leakage of fuel cell bipolar plates, the bipolar plate comprising a cooling fluid inlet (1), an air inlet (2), a cooling fluid outlet (3), and an air outlet (4), and a cooling fluid channel connecting the cooling fluid inlet (1) and the cooling fluid outlet (3), and an air flow channel connecting the air inlet (2) and the air outlet (4), characterized in that, The fixture includes an upper end plate (8), a lower end plate (12), and a pull rod (13). Multiple bipolar plates (10) are stacked between the upper end plate (8) and the lower end plate (12) and fixed by the pull rod (13). Adjacent bipolar plates (10) and the bipolar plates (10) are sealed with the upper end plate (8) and the lower end plate (12) by a sealing element (11). The upper end plate (8) and the lower end plate (12) are provided with a fluorescent colorimetric reagent solution inlet (5) and a fluorescent colorimetric reagent outlet. The fluorescent colorimetric reagent solution outlet (7), and the hot air inlet (6) and hot air outlet (9) are provided, wherein the fluorescent colorimetric reagent solution inlet (5) is connected to the cooling fluid inlet (1) of the bipolar plate (10), the fluorescent colorimetric reagent solution outlet (7) is connected to the cooling fluid outlet (3) of the bipolar plate (10), the hot air inlet (6) is connected to the air inlet (2) of the bipolar plate (10), and the hot air outlet (9) is connected to the air outlet (4) of the bipolar plate (10). The fluorescent colorimetric reagent solution inlet (5) and fluorescent colorimetric reagent solution outlet (7) are connected to the fluorescent colorimetric reagent solution storage tank through a circulation pipeline, and a pump and a heater are provided on the circulation pipeline; The fluorescent colorimetric reagent solution storage tank contains a water-soluble fluorescent agent with a concentration of 200-2000 ppm; The temperature of the hot air introduced into the tooling through the hot air inlet (6) is 40-80℃; The number of bipolar plates (10) stacked between the upper end plate (8) and the lower end plate (12) is 2-200.

2. The batch testing fixture for fuel cell bipolar plate leakage according to claim 1, characterized in that, The water-soluble fluorescent agents include stilbene derivatives, phenylpyrazoline derivatives, benzimidazole derivatives, benzoxazole derivatives, coumarin derivatives, and naphthalene dicarboximide derivatives or disodium salts of oxanthracene rings.

3. The batch testing fixture for fuel cell bipolar plate leakage according to claim 1, characterized in that, The water-soluble fluorescent agent exhibits fluorescence under ultraviolet light in the range of 365 nm to 405 nm.

4. The batch testing fixture for fuel cell bipolar plate leakage according to claim 1, characterized in that, The hot air inlet (6) is connected to the air compressor through a pipe, and an air heater is provided on the pipe.

5. A method for detecting fuel cell bipolar plate leakage using the batch detection fixture described in claim 1, characterized in that, Includes the following steps: Step 1: Stack bipolar plates (10) between the upper end plate (8) and the lower end plate (12), with each bipolar plate (10) separated by a seal (11); Step 2: Use deionized water or antifreeze as solvent and water-soluble fluorescent agent as solute to prepare a fluorescent colorimetric solution with a concentration of 200-2000 ppm; Step 3: Heat the prepared fluorescent color developer solution to 40-80℃, pump it into the tooling, and let it flow from the fluorescent color developer solution inlet (5) into the cooling fluid inlet (1) of each bipolar plate. It flows through the cooling fluid channel and from the cooling fluid outlet (3) to the fluorescent color developer solution outlet (7), so that the fluid pressure in the cooling fluid channel is maintained at 20-200kPa and the flow rate is 0.1-1m / s. Let it stand for 1-7 days. At the same time, introduce 40-80℃ hot air through the hot air inlet (6), let it flow through the air channel of the bipolar plate, and discharge it from the hot air outlet (9). Step 4; After standing, extract the fluorescent colorimetric reagent solution from the fixture, open the fixture, and disassemble the bipolar plates (10) one by one; Step 5: Place the bipolar plates after testing into a dark room and check for leakage under ultraviolet light.

6. The method according to claim 5, characterized in that, The area on the bipolar plate where fluorescence occurs is the leak point. The degree of leakage can be semi-quantitatively determined based on the size of the area where fluorescence occurs.

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