CN218444350U - Fuel cell stack gas tightness detecting system - Google Patents

Abstract

The utility model discloses a fuel cell pile gas tightness detecting system, include: can provide gaseous air supply and flow detection module, the flow path switching module who is connected with it, flow detection module includes: the flowmeter and the on-off valve assembly are sequentially connected in series, and the measuring range of the flowmeter close to one end of the gas source is smaller than that of the flowmeter far away from one end of the gas source. One end of the air path where the on-off valve assembly is located is connected with the air inlet path, and the other end of the air path is connected with the air path between the two flowmeters with different measuring ranges. The flow path switching module can switch the flow path of gas among the gas source, the flow detection module and the cavity to be tested to form different gas tightness test modes, and the on-off valve assembly is opened or closed under the different gas tightness test modes to enable different flowmeters to preferentially pass the gas or the blowby gas. The utility model discloses fuel cell pile gas tightness detecting system, but each flowmeter fast and stable switching, reading are reliable, can accurate reading let out leakage quantity.

Description

Fuel cell stack gas tightness detecting system

Technical Field

The utility model relates to a fuel cell technical field particularly, relates to a fuel cell pile gas tightness detecting system.

Background

The hydrogen fuel cell is a novel power cell, can provide sufficient power for fuel cell powered vehicles, generates less greenhouse gases after combustion, is environment-friendly and energy-saving, and is popular with consumers. The hydrogen fuel cell generally comprises a hydrogen fuel cell stack, and the hydrogen fuel cell stack can be put into a whole vehicle for use after the airtightness detection of the hydrogen fuel cell stack is qualified. The airtightness detection of the hydrogen fuel cell stack usually needs to detect various outer leaks and various inner leaks and needs to reach a certain airtightness detection standard

In the related art, a galvanic pile airtightness detection device in the fuel cell industry generally adopts a plurality of flow meters connected in parallel, and leakage of different cavities is detected by adopting a set flow meter. When certain leakage of the galvanic pile is tested, the maximum measuring range value of the corresponding flowmeter is possibly exceeded, so that technicians cannot accurately read the actual leakage amount of the galvanic pile; meanwhile, technicians need to manually switch the flowmeters and then conduct testing again, and therefore air tightness testing efficiency is low.

For partial leakage testing of the galvanic pile, the flowmeter with the large range is switched to the flowmeter with the small range for flow timing, the pipeline corresponding to the flowmeter with the small range has no gas, the stabilization time is long, the fluctuation of leakage amount is large, the stabilization is slow, and the airtightness detection time is long. If the detection time is shortened, inaccurate reading of the flowmeter can occur, so that a technician can misjudge the leakage amount.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model aims at providing a fuel cell galvanic pile gas tightness detecting system, fuel cell galvanic pile gas tightness detecting system's flowmeter when the test is scurried the required flowmeter of stable quick, automatically switch over and carry out the reading of reliable scurring leakage volume.

In order to achieve the above purpose, the technical scheme of the utility model is realized like this:

a fuel cell stack gas tightness detection system, comprising: the gas source can provide gas for the cavity to be detected; the flow detection module is connected with the air source through an air inlet air path; the flow detection module includes: the gas inlet end of the flowmeter, which is closest to the gas source, is connected with the gas inlet gas circuit; the range of the flowmeter close to one end of the gas source is smaller than that of the flowmeter far away from one end of the gas source; one end of the gas path where the on-off valve assembly is located is connected with the gas inlet path, and the other end of the gas path where the on-off valve assembly is located is connected to the gas path between the two flowmeters with different measuring ranges; the flow path switching module can switch the flow paths of the gas among the gas source, the flow detection module and the cavity to be tested to form different gas tightness test modes, and the on-off valve assembly is opened or closed under the different gas tightness test modes so that different flowmeters can preferentially pass through the gas provided by the gas source or the blowby gas in the cavity to be tested.

According to the fuel cell stack gas tightness detection system provided by the embodiment of the utility model, after a plurality of flowmeters are connected in series, because the flowmeter with smaller range is closest to the gas source, when the gas tightness detection starts, the flowmeter with the smallest range can also enter gas; the on-off valve assembly mainly controls the use of the flowmeter with larger measuring range, and does not interfere the air path on-off of the flowmeter with the smallest measuring range; when the leakage amount of the cavity to be measured is small, each flowmeter can pass through gas, and the flowmeter with a small measuring range can more accurately read the leakage amount and the reading; when the leakage amount of the cavity to be measured is large, the on-off valve assembly can enable gas in a gas source or blowby gas in the cavity to be measured to preferentially enter the flowmeter with a larger measuring range, so that the flowmeter with the larger measuring range can rapidly discharge leaked interference gas, the stability time of each flowmeter is saved, and the leakage amount in the measuring range can be rapidly read; when the flow meter with the minimum use range needs to be switched from the flow meter with the large use range, the on-off valve assembly is closed, so that gas preferentially passes through the flow meter with the minimum use range, and the quick and stable switching is realized. Therefore, under the switching of different air tightness test modules, each flowmeter can be switched quickly and stably, the reading can be quickly and reliably realized, and the leakage quantity can be accurately read.

In addition, according to the fuel cell stack airtightness detection system of the present invention, the following additional technical features may also be provided:

according to some embodiments of the utility model, the flowmeter includes first flowmeter, second flowmeter and the third flowmeter of establishing ties in proper order, the first range of first flowmeter is less than the second range of second flowmeter, the second range is less than the third range of third flowmeter.

Optionally, the on-off valve assembly includes a first on-off valve, one end of the gas path where the first on-off valve is located is connected to the gas inlet gas path, and the other end of the gas path where the first on-off valve is located is connected to the gas path between the second flowmeter and the first flowmeter; when the measuring range reading of the first flowmeter does not reach the upper limit value of the first measuring range, closing the first on-off valve; and when the range reading of the first flowmeter exceeds the upper limit value of the first range and the range reading of the second flowmeter is within the second range, the first on-off valve is opened.

Advantageously, the on-off valve assembly further comprises a second on-off valve, one end of a gas path where the second on-off valve is located is connected with the gas inlet path, and the other end of the gas path where the second on-off valve is located is connected to a gas path between the second flowmeter and the third flowmeter; and when the range reading of the second flowmeter exceeds the upper limit value of the second range, closing the first on-off valve and opening the second on-off valve.

Optionally, the first on-off valve and the second on-off valve are electromagnetic switch valves.

According to some embodiments of the utility model, the initial stage of the cavity that awaits measuring takes place the blowby, first on-off valve is opened, so that the second flowmeter discharges the blowby gas.

According to some embodiments of the utility model, it is a plurality of the flowmeter establish ties in proper order after through exhaust passage with the flow path switches the module and connects.

According to the utility model discloses a some embodiments, flow path switching module includes many test branches and ooff valve, every all be equipped with an ooff valve on the test branch.

Optionally, the cavity to be tested comprises a cavity, a hydrogen cavity and a water cavity, the test branch comprises three first test branches, three second test branches and a third test branch, one end of each of the three first test branches is connected to the cavity, the hydrogen cavity and the water cavity, and the other end of each of the three first test branches is connected to the gas inlet path; one end of each of the three second testing branches is connected to a different first testing branch, the other end of each of the three second testing branches is connected to a third testing branch, the other end of the third testing branch is communicated to the air inlet path, and the exhaust channel is connected with the third testing branch.

According to some embodiments of the present invention, the fuel cell stack gas tightness detection system further comprises a gas circuit control valve, the gas circuit control valve is disposed on the gas inlet circuit, the gas circuit control valve is located at the downstream of the connection end of the first testing branch circuit and the gas inlet circuit, and the gas circuit control valve is located at the upstream of the connection end of the third testing branch circuit and the gas inlet circuit; and/or, further comprising a first relief valve provided on the exhaust passage; and/or, the test device also comprises a second relief valve, and the second relief valve is arranged on the third test branch.

Drawings

The accompanying drawings, which form a part of the present disclosure, are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and together with the description serve to explain the present disclosure. In the drawings:

fig. 1 is a schematic diagram of a stack structure of fuel cells according to some embodiments of the present invention.

Fig. 2 is a schematic structural view of a membrane electrode according to some embodiments of the present invention.

Fig. 3 is a schematic structural view of a bipolar plate according to some embodiments of the present invention.

Fig. 4 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A of fig. 3.

Fig. 5 is a schematic diagram of a galvanic pile gas tightness detection system in the prior art.

Fig. 6 is a diagram illustrating the detection of the stack during the test of water breakthrough hydrogen space in the prior art.

Fig. 7 is a schematic diagram of a fuel cell stack gas tightness detection system according to some embodiments of the present invention.

Fig. 8 is a schematic diagram of detection when the fuel cell stack gas tightness detection system according to some embodiments of the present invention detects hydrogen breakthrough.

Reference numerals are as follows:

900. a fuel cell;

910. a blind end plate; 920. a negative current collector;

930. a bipolar plate;

931. a flow channel; 932. a second frame region; 933. a second lumen aperture;

934. a water passage; 935. a hydrogen channel; 936. an empty channel;

940. a membrane electrode; 941. an intermediate reaction zone; 942. a first bezel area; 943. a first cavity bore;

950. a positive collector plate; 960. a gas port end plate;

800. a galvanic pile air tightness detection system;

810. an air inlet source; 811. an air inlet path;

821. a first mass flow meter; 822. a second mass flow meter; 823. a third mass flow meter;

831. a first control valve; 832. a second control valve; 833. a third control valve;

841. an air tightness test branch; 842. an on-off control valve;

851. an airtight chamber to be tested;

1000. a fuel cell stack gas tightness detection system;

100. a gas source; 110. a gas inlet circuit; 120. a gas path control valve;

200. a flow detection module;

210. a flow meter; 211. a first flow meter; 212. a second flow meter; 213. a third flow meter;

220. a make-and-break valve assembly; 221. a first on-off valve; 222. a second on-off valve;

230. an exhaust passage; 240. a first bleed valve;

300. a flow path switching module;

310. testing the branch circuit;

311. a first test branch; 312. a second test branch; 313. a third test branch;

314. a second bleed valve;

320. an on-off valve;

400. a cavity to be tested; 410. a cavity; 420. a hydrogen chamber; 430. a water cavity.

Detailed Description

It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail with reference to fig. 1 to 8 in conjunction with the embodiments.

Referring to fig. 1-4, a fuel cell stack gas tightness detection system 1000 as described herein is primarily directed to the stack of a fuel cell 900.

As shown in fig. 1, the stack of the fuel cell 900 includes a gas port end plate 960, a positive current collecting plate 950, a bipolar plate 930, a membrane electrode 940, a negative current collecting plate 920, a blind end plate 910, and other auxiliary components, and the stack, which is the core part of the fuel cell 900, is formed by alternately stacking the bipolar plates 930 and the membrane electrodes 940 layer by layer.

As shown in fig. 2, the membrane electrode 940 is a thin sheet-like component, which includes a first rim 942 and an intermediate reaction region 941, both of which are made of soft elastic material. The intermediate reaction zone 941 includes a proton exchange membrane, a catalyst layer, and a gas diffusion layer. Six first cavity holes 943 are provided in the first rim area 942.

As shown in fig. 3 and 4, the bipolar plate 930 includes a cathode plate and an anode plate attached to each other, and the cathode plate and the anode plate are respectively provided with a second frame 932, a plurality of second cavity holes 933, and a flow passage 931. An air channel 936 for passing air is arranged on one surface of the cathode plate, which is far away from the anode plate, a hydrogen channel 935 for passing hydrogen is arranged on one surface of the anode plate, which is far away from the cathode plate, and a flow passage 931 in the middle of the bipolar plate 930 is a water channel 934 for passing cooling water. In general, the water passages 934, the hydrogen passages 935, and the empty passages 936 are well separated from each other in airtightness, and in the case where a leak occurs in each passage, airtightness is reduced. When the gas in the water channel 934, the hydrogen channel 935 and the empty channel 936 leaks to the outside, the gas leaks to the outside; the water channel 934, the hydrogen channel 935 and the empty channel 936 form an inner leakage when the water channel, the hydrogen channel and the empty channel are leaked towards each other, and the cell stack needs to be subjected to a cell stack air tightness test before being used formally.

The stack gas tightness test generally comprises 4 outer leaks and 8 inner leaks. The 4-item leakage comprises: hydrogen leakage, air leakage, water leakage and three-cavity total leakage. The 8-item endoleak includes: empty, hydrogen scurries water, empty hydrogen scurries, empty water scurries, water scurries hydrogen, water scurries empty and hydrogen empty and scurries water, the utility model discloses a fuel cell galvanic pile gas tightness detecting system 1000 then can be used to test the above-mentioned condition of leaking outward and interior hourglass.

According to the utility model discloses a fuel cell pile gas tightness detecting system 1000, as shown in fig. 7, include: the system comprises a gas source 100, a flow detection module 200 and a flow path switching module 300.

As shown in fig. 7, the gas source 100 can provide gas to the chamber 400 to be measured; the flow rate detection module 200 is connected to the air source 100 through the air inlet path 110, so that when the air source 100 supplies air, the flow rate detection module 200 can measure the mass flow rate of the air flow flowing through, thereby indirectly obtaining the leakage rate of the cavity 400 to be measured.

With continued reference to fig. 7, the flow detection module 200 includes: a plurality of flow meters 210 and an on-off valve assembly 220 in series.

The measuring range of each flow meter 210 is different, and the gas inlet end of the flow meter 210 closest to the gas source 100 is connected with the gas inlet gas circuit 110; the range of the flow meter 210 near the end of the gas source 100 is less than the range of the flow meter 210 at the end remote from the gas source 100. That is, the plurality of flow meters 210 are connected in series and communicate with the gas inlet path 110 in a range from small to large.

One end of the gas path in which the on-off valve assembly 220 is located is connected to the gas path 110, and the other end of the gas path in which the on-off valve assembly 220 is located is connected to the gas path between the two flow meters 210 with different measuring ranges, that is, for the flow meter 210 with the smallest measuring range close to the gas source 100, the on-off valve assembly 220 is not additionally arranged at the gas inlet end, and whether the flow meter 210 with the smallest measuring range admits gas is not influenced by the on-off valve assembly 220.

Further, as shown in fig. 7, the flow path switching module 300 may switch the flow paths of the gas among the gas source 100, the flow rate detection module 200 and the cavity 400 to be tested to form different gas tightness test modes, and the on-off valve assembly 220 is opened or closed in the different gas tightness test modes to enable different flowmeters 210 to preferentially pass through the gas provided by the gas source 100 or the blowby gas in the cavity 400 to be tested, so as to adapt to accurate measurement of different leakage amounts.

According to the structure, after the fuel cell stack airtightness detection system 1000 according to the embodiment of the present invention has the plurality of flowmeters 210 connected in series, since the flowmeter 210 with a smaller range is closest to the gas source 100, the flowmeter 210 with the smallest range can also enter gas when the airtightness detection starts; the on-off valve assembly 220 mainly controls the flowmeter 210 with a larger measuring range to rapidly pass through gas, and does not interfere with the gas path on-off of the flowmeter 210 with a minimum measuring range, so that the flowmeter 210 with the minimum measuring range can be always introduced with gas and has certain gas pressure, and the flowmeter is in a usable state at any time.

When the leakage amount of the cavity 400 to be measured is small, because the flowmeters 210 are connected in series, each flowmeter 210 can pass through gas, and the flowmeter 210 with a small measuring range can more accurately read out the small leakage amount and the small reading. In this case, the other flow meters 210 have a wide range of measurement ranges and, although there are readings, the accuracy of the measurement for a smaller leakage amount is insufficient, and thus, only the flow meter 210 with the smallest measurement range is required to perform a precise reading.

When the leakage amount of the cavity 400 to be measured is large, the on-off valve assembly 220 can enable the gas in the gas source 100 to preferentially and quickly enter the flowmeter 210 with a large measuring range, so that the flowmeter 210 with the large measuring range can quickly discharge the leaked interference gas, the stability time of each flowmeter 210 is saved, the leakage amount in the measuring range can be quickly read, and the operation is quick.

When the leakage amount is gradually reduced and the flow meter 210 with the minimum using range needs to be switched from the flow meter 210 with the larger range, the on-off valve assembly 220 is closed, so that the gas preferentially passes through the flow meter 210 with the minimum using range, and because the flow meter 210 with the minimum using range is always communicated with a certain amount of gas pressure, the flow meter 210 with the minimum using range does not need to wait for charging when the flow meter 210 with the minimum using range is switched from the flow meter 210 with the larger range to the flow meter 210 with the minimum using range, and the quick and stable switching can be realized.

Therefore, under the switching of different airtightness test modules, each flowmeter 210 can be switched quickly and stably, and can realize quick and reliable reading and accurate reading of leakage quantity.

It can be understood that, as shown in fig. 5, for the electric pile air tightness detection system 800 in the prior art, three parallel first mass flow meters 821, second mass flow meters 822 and third mass flow meters 823 are adopted and connected with an air intake path 811, and meanwhile, a first control valve 831 is arranged in front of the first mass flow meter 821 to achieve on-off of the first mass flow meter 821; a second control valve 832 is arranged at the front part of the second mass flow meter 822 for realizing the on-off of the second mass flow meter; the front part of the third mass flowmeter 823 is provided with a third control valve 833 to realize on-off of the third mass flowmeter, so that selection of mass flowmeters with different measuring ranges can be realized, and the rear end of each mass flowmeter is provided with an independent exhaust gas path. In addition, the airtight test branch 841 is respectively communicated with an airtight chamber to be tested 851, an air inlet path 811 and three mass flowmeters connected in parallel. Each airtight testing branch 841 is provided with an on-off control valve 842, and different airtight detection modes can be formed by opening different on-off control valves 842. In the case that the second control valve 832 is opened and the first control valve 831 and the third control valve 833 are both closed, the second mass flowmeter 822 with the larger range can measure the leakage amount; when it is desired to measure a small leak and switch to the first mass flow meter 821 with a smaller turndown next, it is necessary to close the second control valve 832 and then open the first control valve 831. Since the three mass flow meters are connected in parallel, when the first control valve 831 is opened and the previous first mass flow meter 821 is not filled with gas, the gas will slowly pass through the first mass flow meter 821, and the first mass flow meter 821 needs a certain time to stabilize the reading.

As shown in fig. 6, in the detection mode of hydrogen breakthrough, when the water cavity to be detected in the airtight cavity to be detected 851 is filled with gas at a certain pressure, the water cavity to be detected may extrude the hydrogen cavity to be detected and the cavity to be detected, so that the hydrogen cavity is deformed to generate redundant gas. The hydrogen cavity body corresponds to the first mass flow meter 821 with the minimum use range to realize measurement, and the hydrogen cavity body has no pressure, so that the first mass flow meter 821 will need a long stabilization time when testing the leakage amount, and often needs a stabilization time of 2000 seconds or even 3000 seconds.

And the utility model provides a fuel cell galvanic pile gas tightness detecting system 1000 then can be to the problem that the airtight detecting system 800 test of current galvanic pile let out leakage quantity and have, and realize fast, switch over the flowmeter 210 of different ranges steadily, and length, detection efficiency height, detection precision are good when stable.

Alternatively, the adjustment of the pressure of the gas output by the gas source 100 may be achieved by adding a pressure regulating valve to achieve different tightness test modes.

In some embodiments of the present invention, as shown in fig. 7, the flow meter 210 includes a first flow meter 211, a second flow meter 212, and a third flow meter 213 connected in series, the first measurement range of the first flow meter 211 is smaller than the second measurement range of the second flow meter 212, and the second measurement range of the second flow meter 212 is smaller than the third measurement range of the third flow meter 213. That is to say, three flowmeter 210 all has different range and different detection precision to can adapt to the not gas quantity of equidimension of accurate detection, make things convenient for the accurate reading of operating personnel, thereby judge how much, the efficiency of software testing of leaking the volume. Since the leakage amount of the gas is not equal in the different airtightness test modes, the required detection accuracy of the flowmeter 210 is different, and the required range of the flowmeter 210 is also different. The gas with the least leakage amount in each airtightness test mode can be accurately read out by the first flowmeter 211 with the small measurement range, and the gas with the most leakage amount in each airtightness test mode can be accurately read out by the third flowmeter 213 with the largest measurement range. The accuracy of the second flow meter 212 is between that of the first flow meter 211 and that of the third flow meter 213, and different air tightness test modes select different flow meters 210, so that each reading is stable and accurate.

It should be noted that the flow meter 210 used in the present invention is a mass flow meter, and is used for detecting mass flow, which is a flow meter for detecting the air tightness of the galvanic pile and is commonly used in the industry; the on-off valve assembly 220 is switched mainly according to the tested airtightness test mode.

For example, in a specific example, the first flow meter 211 has a range of 0.1 to 5SCCM (Standard Cubic centimeter per Minute); the range of the second flow meter 212 is 10 to 50SCCM, and the range of the third flow meter 213 is 50 to 1000SCCM.

Alternatively, as shown in fig. 7, the on-off valve assembly 220 includes a first on-off valve 221, one end of the gas path in which the first on-off valve 221 is located is connected to the gas path 110, and the other end of the gas path in which the first on-off valve 221 is located is connected to the gas path between the second flowmeter 212 and the first flowmeter 211. The first on-off valve 221 is mainly used to control the on-off of the flow meter 210 on the subsequent gas path. When the first on-off valve 221 is opened, the gas path where the first on-off valve 221 is located and the gas path where the first flowmeter 211 is located are connected in parallel, and for the first flowmeter 211 with the smallest measuring range, the flow rate of the gas measured by the first flowmeter is smaller, and the on-off section is usually small so that the overflowing is stable and the measured reading is accurate, more gas passing through the gas inlet path 110 rapidly flows through the gas path where the first on-off valve 221 is located and enters the second flowmeter 212; less gas passes through the first flow meter 211. At this time, it is ensured that the first flow meter 211 always has gas passing through. In addition, since the third flow meter 213 is connected in series to the rear end of the second flow meter 212, the second flow meter 212 will continue to flow through the third flow meter 213 after passing through the gas.

Further, when the range reading of the first flow meter 211 does not reach the upper limit value of the first range, the first on-off valve 221 is closed, so that the gas passing through the gas inlet path 110 preferentially passes through the first flow meter 211, and since the amount of the gas passing through is within the range of the first flow meter 211, the first flow meter 211 can accurately read the leakage amount.

Further, when the range reading of the first flow meter 211 exceeds the upper limit of the first range, the first flow meter 211 cannot accurately read the leakage amount. At this time, the reading of the second flowmeter 212 may be observed, and if the reading is within the second range, the first on-off valve 221 is opened to allow the gas to preferentially pass through the second flowmeter 212, so that the gas flows rapidly, and the second flowmeter 212 may stably read the airtightness test mode of the medium leakage amount.

Optionally, as shown in fig. 2, the on-off valve assembly 220 further includes a second on-off valve 222, one end of the gas path in which the second on-off valve 222 is located is connected to the gas path 110, and the other end of the gas path in which the second on-off valve 222 is located is connected to the gas path between the second flow meter 212 and the third flow meter 213. Similar to the first on-off valve 221, the second on-off valve 222 connects the gas paths of the first flowmeter 211 and the second flowmeter 212 in parallel with the gas path of the second on-off valve 222, so that after the second on-off valve 222 is opened, a large amount of gas preferentially passes through the gas path of the second on-off valve 222 and enters the third flowmeter 213, and thus the third flowmeter 213 can rapidly measure the leakage amount.

Advantageously, when the range reading of the second flowmeter 212 exceeds the upper limit value of the second range, the first on-off valve 221 is closed and the second on-off valve 222 is opened, that is, for the airtight test mode with a large leakage amount, the second flowmeter 212 cannot accurately read the scales, and the third flowmeter 213 with a larger range must be adopted; the second shut-off valve 222 is opened, so that the third flow meter 213 can quickly and accurately test a large leakage amount. Before the second on-off valve 222 is not opened, because the first flowmeter 211, the second flowmeter 212 and the third flowmeter 213 are connected in series, in the detection process, gas sequentially passes through the first flowmeter 211, the second flowmeter 212 and the third flowmeter 213, a certain amount of gas also passes through the third flowmeter 213 when the second on-off valve 222 is closed, and switching, quick reading and convenient operation are easier after the second on-off valve 222 is opened.

Alternatively, the first on-off valve 221 and the second on-off valve 222 are electromagnetic switch valves, and the electromagnetic switch valves can be opened and closed by setting control logic. Therefore, the present invention can design a controller, and electrically connect the first on-off valve 221 and the second on-off valve 222 to the controller, so as to automatically select the corresponding flow meter 210 in each airtightness testing mode, thereby making full use of the three flow meters 210.

In other examples, the first on-off valve 221 and the second on-off valve 222 may be only manual on-off valves, and the measurement is performed by a worker manually opening and closing the valves according to a test situation in the field, which is not limited herein.

In some embodiments of the present invention, in an initial stage of the cavity 400 to be tested having blowby, the first on-off valve 221 is opened to allow the second flowmeter 212 to discharge blowby gas, that is, when blowby occurs and the air tightness test is performed, the first on-off valve 221 may be opened at the beginning to allow more interference gas to be discharged from the second flowmeter 212 and the third flowmeter 213, the second flowmeter 212 and the third flowmeter 213 may measure a larger gas flow rate and a larger gas flow rate per unit time, and in order to allow the second flowmeter 212 and the third flowmeter 213 to read accurately and stably, the on-off section of the second flowmeter 212 and the third flowmeter 213 is generally larger than that of the first flowmeter 211, so that the interference gas can be removed in an accelerated manner, and then the first on-off valve 221 is controlled to be continuously opened or closed according to the actual leakage amount, and the second on-off valve 222 is continuously opened or closed, so as to select the flowmeter 210 with the appropriate measurement range, thereby being capable of reliably and accurately measuring the air tightness test mode.

Alternatively, as shown in fig. 7, a plurality of flow meters 210 are connected in series and then connected to the flow path switching module 300 through the exhaust passage 230, without providing a separate exhaust path at the rear end of each mass flow meter as in the prior art. The utility model discloses the great flowmeter of mesoscale range only is used for the exhaust when need not be used for the reading, omits arranging of many exhaust passage 230.

Optionally, the air tightness test mode comprises a first test mode with a first air tightness criterion, a second test mode with a second air tightness criterion, and a third test mode with a third air tightness criterion, the first test mode taking the first flow meter 211 readings, the second test mode taking the second flow meter 212 readings, and the third test mode taking the third flow meter 213 readings. That is, the accuracy of the first air tightness standard is higher, and the leakage amount of the cavity 400 to be tested in the first test mode is the smallest, usually several standard cubic centimeters per minute; the second airtight standard has the second highest precision, and the leakage amount of the cavity 400 to be tested in the second test mode is medium, usually dozens of standard cubic centimeters per minute; the third airtight standard has a relatively low accuracy, and the leakage amount of the chamber 400 to be tested in the third test mode is the largest, typically hundreds of standard cubic centimeters per minute. The airtightness test modes with different airtightness standards adopt different flowmeters 210 for reading, so that the accuracy of the measured leakage amount can be effectively improved, the detection speed is improved, and the operation of detection personnel is facilitated.

The cavity 400 to be measured in the utility model comprises a cavity 410, a hydrogen cavity 420 and a water cavity 430, wherein the cavity 410 is a cavity for accommodating air in the galvanic pile of the fuel cell 900; the water chamber 430 is used to refer to a cavity in the stack of the fuel cell 900 for containing water or cooling fluid; the hydrogen chamber 420 refers to a chamber for accommodating hydrogen in the stack of the fuel cell 900.

The air tightness test mode in the utility model corresponds to 4 outer leaks and 8 inner leaks, and is respectively designed with a hydrogen outer leak detection mode, an empty outer leak detection mode, a water outer leak detection mode and a three-cavity total outer leak detection mode; a hydrogen breakthrough detection mode, a hydrogen breakthrough water detection mode, an air breakthrough hydrogen detection mode, an air breakthrough water detection mode, a water breakthrough hydrogen detection mode, a water breakthrough air detection mode, a water breakthrough hydrogen air detection mode, and a hydrogen breakthrough water detection mode.

The hydrogen leakage detection mode is used to detect the total amount of gas leakage from the hydrogen chamber 420 per unit time under a certain pressure. The air leakage detection mode is used to detect the total amount of air leakage per unit time of the cavity 410 under a certain pressure. The water leakage detecting mode is used to detect the total amount of the gas introduced into the water chamber 430 per unit time under a certain pressure difference from the water chamber 430. The three-chamber total leakage detection mode is used to detect the total amount of gas leakage in a unit time of the hydrogen chamber 420, the cavity 410 and the water chamber 430 under a certain pressure.

The hydrogen breakthrough detecting mode is used to detect the total amount of gas in the hydrogen chamber 420 flowing into the cavity 410 per unit time with a certain pressure difference. The hydrogen breakthrough detection mode is used to detect the total amount of gas leakage from the hydrogen chamber 420 to the water chamber 430 per unit time under a certain unit of pressure difference. The air hydrogen breakthrough detection mode is used to detect the total amount of gas in the cavity 410 that flows into the hydrogen chamber 420 per unit time at a certain pressure difference. The air-blow-by detection mode is used to detect the total amount of gas leaking into the water chamber 430 per unit time under a certain unit of pressure difference from the gas in the cavity 410. The water breakthrough hydrogen detection mode is used to detect the total amount of gas introduced into the water chamber 430 per unit time leaking into the hydrogen chamber 420 at a certain pressure difference. The water breakthrough detecting mode is used to detect the total amount of gas introduced into the water chamber 430 leaking into the cavity 410 per unit time with a certain pressure difference. The water breakthrough hydrogen empty detection mode is used to detect the total amount of gas introduced into the water chamber 430 leaking into the hydrogen chamber 420 per unit time with a certain pressure difference. The hydrogen air water breakthrough detection mode is used to detect the total amount of gas leaking from the hydrogen chamber 420 and the cavity 410 toward the water chamber 430 at a certain pressure difference per unit time.

In some specific examples, the leakage amount in the water leakage detection mode, the water-to-air hydrogen-to-air detection mode and the hydrogen-to-air-to-water detection mode is small, for example, several times of standard cubic centimeters per minute, and meets the requirement of the first air tightness standard, and the leakage amount can be accurately measured in these air tightness test modes by using the first flowmeter 211.

In some embodiments, the leakage amount is slightly larger in the hydrogen leakage detection mode, the air leakage detection mode and the three-cavity total leakage detection mode, for example, several tens of standard cubic centimeters per minute, and meets the requirement of the second air tightness standard, and the air tightness test modes can accurately measure the leakage amount by using the second flowmeter 212.

In some specific examples, the leakage amount in the hydrogen breakthrough detection mode and the air breakthrough hydrogen detection mode is larger, for example, the leakage amount is usually hundreds of standard cubic centimeters per minute, and meets the requirement of the third air tightness standard, and the leakage amount can be accurately measured by the air tightness test modes through measurement by the third flow meter 213.

Other non-mentioned modes of airtightness detection may also select different flow meters 210 for measurement according to actual needs.

In some examples, referring to the water breakthrough hydrogen empty detection mode shown in fig. 8, before measurement, the second flowmeter 212 may be started to accelerate removal of the interference gas generated by the water chamber 430 squeezing the hydrogen chamber 420 and the cavity 410, and then switched to the first flowmeter 211, so as to avoid directly using the small-range flowmeter 210 to test the leakage amount in the water breakthrough hydrogen empty detection mode, thereby solving the problem that the stability time is long when the flowmeter 210 with the small range tests the breakthrough. The curves shown in fig. 8 indicate that the first flow meter 211 can stabilize quickly when tested.

In some embodiments of the present invention, as shown in fig. 7, the flow path switching module 300 includes a plurality of testing branches 310 and switch valves 320, each testing branch 310 is provided with a switch valve 320, each switch valve 320 can realize on-off control of the testing branch 310 where it is located, and different air tightness testing modes can be realized through on-off combinations of the switch valves 320 on different testing branches 310. Different flowmeters 210 can be selected corresponding to different air tightness test modes through different on-off valve assemblies 220, so that accurate test of leakage amount in different air tightness modes is realized.

As shown in fig. 7, the testing branch 310 includes three first testing branches 311, three second testing branches 312, and one third testing branch 313, one end of each of the three first testing branches 311 is connected to the cavity 410, the hydrogen cavity 420, and the water cavity 430, and the other end of each of the three first testing branches 311 is connected to the inlet gas circuit 110; one end of each of the three second testing branches 312 is connected to a different first testing branch 311, the other end of each of the three second testing branches 312 is connected to a third testing branch 313, the other end of the third testing branch 313 is communicated to one end of the inlet gas path 110 close to the flow detection module 200, and the exhaust channel 230 is connected to the third testing branch 313. Therefore, during the test, a certain air pressure and air flow can be formed through the opening and closing control of each switch valve 320 and the ventilation of the air source 100, so as to measure different air tightness modes. When the first testing branch 311 needs to be communicated, the on-off valve 320 on the first testing branch is opened; when the second testing branch 312 needs to be communicated, the on-off valve 320 on the second testing branch is opened; the third test branch 313 opens the on-off valve 320 located thereon when communication is required.

Advantageously, the exhaust channel 230 is connected to the air path between the switch valve 320 on the third testing branch 313 and the second testing branch 312, so that the switch valve 320 on the third testing branch 313 does not need to be opened when a leak is tested; in the event of an internal leak, the switching valve 320 in the third test branch 313 is then opened.

In some embodiments of the present invention, as shown in fig. 7, the fuel cell stack gas tightness detecting system 1000 further includes a gas path control valve 120, the gas path control valve 120 is disposed on the gas inlet path 110, the gas path control valve 120 is located at the downstream of the connection end of the first testing branch 311 and the gas inlet path 110, and the gas path control valve 120 is located at the upstream of the connection end of the third testing branch 313 and the gas inlet path 110; when the air path control valve 120 is opened, the air source 100 can be conveyed towards the air inlet path 110, so that the air flow can be directly introduced into the cavity 400 to be tested from the first testing branch 311, or when the leakage of a certain cavity 400 to be tested is measured, the air in the air inlet path 110 flows to the flow detection module 200, and then passes through the third testing branch 313, the second testing branch 312 and the first testing branch 311 which are correspondingly communicated with the leaked cavity 400 to be tested, so as to realize the air tightness detection when the cavity 400 to be tested leaks; or, in the process of measuring the internal leakage, the blowby gas flowing into the cavity 400 to be measured may sequentially flow to the flow detection module 200 through the first test branch 311, the second test branch 312, the third test branch 313 and the gas inlet path 110 connected thereto, thereby achieving measurement of the blowby amount of the internal leakage.

Alternatively, as shown in fig. 7, the fuel cell stack gas tightness detection system 1000 further includes a first bleed valve 240, the first bleed valve 240 is disposed on the exhaust passage 230 so as to bleed the gas flowing through each flow meter 210 into the air, and when an internal leakage is detected, the first bleed valve 240 is opened so that the leaked gas can smoothly flow through the flow rate detection module 200 and each flow meter 210 has a reading. When the leakage is detected, the first bleed valve 240 is closed, so that the gas passing through the gas source 100 can enter the chamber 400 to be tested, where the leakage occurs, from the flow detection module 200 through the exhaust channel 230, the third test branch 313, the second test branch 312, and the first test branch 311, and thus the amount of the leakage gas occurring in the chamber 400 to be tested can be measured.

Optionally, as shown in fig. 7, the fuel cell stack gas tightness detection system 1000 further includes a second relief valve 314, and the second relief valve 314 is disposed on the third test branch 313. When the air tightness test is not needed, the second bleed valve 314 may be opened to bleed the gas on each test branch 310, so that the fuel cell stack air tightness detection system 1000 completes the pressure relief, thereby improving the safety during the test.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A fuel cell stack gas tightness detection system (1000), characterized by comprising:

the gas source (100), the gas source (100) can provide gas for the cavity (400) to be tested;

the flow detection module (200), the flow detection module (200) is connected with the air source (100) through an air inlet gas circuit (110); the flow detection module (200) comprises:

a plurality of flow meters (210) connected in series in sequence, wherein the range of the measuring range of each flow meter (210) is different, and the gas inlet end of the flow meter (210) closest to the gas source (100) is connected with the gas inlet gas circuit (110); the range of the flow meter (210) near the end of the gas source (100) is smaller than the range of the flow meter (210) far from the end of the gas source (100);

the gas path of the on-off valve assembly (220) is connected with the gas inlet gas path (110), and the other end of the gas path of the on-off valve assembly (220) is connected with the gas path between the two flowmeters (210) with different measuring ranges;

the flow path switching module (300) is used for switching the flow path of the gas among the gas source (100), the flow detection module (200) and the cavity (400) to be tested so as to form different gas tightness test modes, and the on-off valve assembly (220) is opened or closed under the different gas tightness test modes so that different flow meters (210) can preferentially pass the gas provided by the gas source (100) or the blowby gas in the cavity (400) to be tested.

2. The fuel cell stack gas tightness detection system (1000) according to claim 1, wherein the flow meter (210) includes a first flow meter (211), a second flow meter (212), and a third flow meter (213) connected in series in this order, a first measurement range of the first flow meter (211) is smaller than a second measurement range of the second flow meter (212), and the second measurement range is smaller than a third measurement range of the third flow meter (213).

3. The fuel cell stack gas tightness detection system (1000) according to claim 2, wherein the on-off valve assembly (220) comprises a first on-off valve (221), one end of a gas path where the first on-off valve (221) is located is connected with the gas inlet path (110), and the other end of the gas path where the first on-off valve (221) is located is connected with a gas path between the second flowmeter (212) and the first flowmeter (211);

closing the first on-off valve (221) when the range reading of the first flow meter (211) does not reach the upper limit value of the first range;

and when the range reading of the first flow meter (211) exceeds the upper limit value of the first range and the range reading of the second flow meter (212) is in the second range, the first on-off valve (221) is opened.

4. The fuel cell stack gas tightness detection system (1000) according to claim 3, wherein the on-off valve assembly (220) further comprises a second on-off valve (222), one end of a gas path where the second on-off valve (222) is located is connected to the gas inlet path (110), and the other end of the gas path where the second on-off valve (222) is located is connected to a gas path between the second flow meter (212) and the third flow meter (213);

when the range reading of the second flow meter (212) exceeds the upper limit value of the second range, the first on-off valve (221) is closed and the second on-off valve (222) is opened.

5. The fuel cell stack gas tightness detection system (1000) according to claim 4, characterized in that said first on-off valve (221) and said second on-off valve (222) are electromagnetic on-off valves.

6. The fuel cell stack gas tightness detection system (1000) according to claim 3, wherein at an initial stage of blowby of the chamber under test (400), the first on-off valve (221) is opened to allow the second flow meter (212) to discharge blowby gas.

7. The fuel cell stack gas tightness detection system (1000) according to claim 1, wherein a plurality of the flow meters (210) are connected in series in sequence and then connected to the flow path switching module (300) through a gas discharge passage (230).

8. The fuel cell stack gas tightness detection system (1000) according to claim 7, wherein the flow path switching module (300) comprises a plurality of test branches (310) and on-off valves (320), one on-off valve (320) being provided on each of the test branches (310).

9. The fuel cell stack gas tightness detection system (1000) according to claim 8, wherein the chamber body (400) to be tested comprises a cavity (410), a hydrogen chamber (420) and a water chamber (430), the testing branch (310) comprises three first testing branches (311), three second testing branches (312) and a third testing branch (313), one end of each of the three first testing branches (311) is connected to the cavity (410), the hydrogen chamber (420) and the water chamber (430), and the other end of each of the three first testing branches (311) is connected to the gas inlet path (110); one end of each of the three second testing branches (312) is connected to a different first testing branch (311), the other end of each of the three second testing branches (312) is connected to the third testing branch (313), the other end of the third testing branch (313) is communicated to one end, close to the flow detection module (200), of the air inlet path (110), and the exhaust channel (230) is connected to the third testing branch (313).

10. The fuel cell stack gas tightness detection system (1000) according to claim 9, further comprising a gas path control valve (120), wherein the gas path control valve (120) is disposed on the gas inlet path (110), the gas path control valve (120) is located downstream of a connection end of the first testing branch (311) and the gas inlet path (110), and the gas path control valve (120) is located upstream of a connection end of the third testing branch (313) and the gas inlet path (110);

and/or further comprising a first relief valve (240), the first relief valve (240) being provided on the exhaust passage (230);

and/or further comprising a second relief valve (314), the second relief valve (314) being provided on the third test branch (313).

Images