CN220288901U - Leakage-proof test equipment for polar plate and membrane electrode of hydrogen fuel cell - Google Patents

Abstract

The utility model provides leakage-proof test equipment for a polar plate and a membrane electrode of a hydrogen fuel cell, belonging to the technical field of hydrogen energy fuel cells; including the casing, two lifter of top inner wall fixedly connected with of casing, the bottom fixedly connected with connecting block of lifter, the bottom fixedly connected with slide bar of connecting block, install two grabbing mechanism on the slide bar, grabbing mechanism's below joint has the second lug, the bottom fixedly connected with of second lug detects the casing. According to the utility model, the grabbing mechanism is arranged, when the detection shell is dismounted, only the rotary handles on two sides are required to rotate along the direction of the third groove, so that the first convex block rotates in a following manner, the column body slides in the sliding groove due to the rotation of the first convex block, the top of the movable claw hook rotates towards the direction close to the protection shell, the bottom of the movable claw hook rotates towards the direction far away from the protection shell, and at the moment, the movable claw hook is not contacted with the second convex block any more, so that the detection shell is dismounted.

Description

Leakage-proof test equipment for polar plate and membrane electrode of hydrogen fuel cell

Technical Field

The utility model relates to the technical field of hydrogen energy fuel cells, in particular to leakage-proof test equipment for a polar plate and a membrane electrode of a hydrogen fuel cell.

Background

The hydrogen fuel is a novel battery type, is often used as an electric automobile battery, has wide market prospect, generates electric energy by converting hydrogen and oxygen into water, provides environment-friendly energy supply for new energy electric automobiles, sequentially stacks polar plates, membrane electrodes and polar plates, then installs the polar plates on the lower end plate of an insulating plate and a current collecting plate, assembles a single cell, orderly stacks the single cell into a galvanic pile, finally installs a screw after the end plate is stacked on the galvanic pile, and completes the assembly of the hydrogen fuel battery.

The prior test equipment such as CN216955003U can automatically stop when the object to be tested passes through the closed detection device on the conveyor belt, the object to be tested is completely covered by the descending of the lifting rod, and then air flow can be output to detect whether the object to be tested leaks or not, but the closed detection device is generally in bolted connection, and when the closed detection device has a problem, corresponding tools are needed to be disassembled, the replacement and maintenance are more troublesome, and the routine cleaning is inconvenient.

Disclosure of Invention

The utility model aims to solve the technical problems that the leakage-proof test equipment for the polar plate and the membrane electrode of the hydrogen fuel cell is used for solving the problems that the existing airtight detection device is generally in bolted connection, corresponding tools are needed to be disassembled when the airtight detection device has problems, the replacement and the maintenance are more troublesome, and the routine cleaning is inconvenient.

In order to solve the technical problems, the utility model provides the following technical scheme:

the utility model provides a leak protection test equipment of hydrogen fuel cell polar plate and membrane electrode, includes the casing, two lifter of top inner wall fixedly connected with of casing, the bottom fixedly connected with connecting block of lifter, the bottom fixedly connected with slide bar of connecting block, install two grabbing mechanisms on the slide bar, grabbing mechanism's below joint has the second lug, the bottom fixedly connected with of second lug detects the casing, the cavity has been seted up to the bottom of detecting the casing, casing top fixedly connected with air pump, the output fixedly connected with of air pump runs through the casing with detect the conveyer belt that the casing was all seted up to the both sides outer wall of casing has offered the transfer port and has offered a plurality of holes runs through, the bottom inner wall fixedly connected with third lug of casing, the top conflict of third lug has the holding down plate, grabbing mechanism includes protective housing and a plurality of movable claw hook, the slide bar runs through the protective housing, the internally mounted of protective housing has the rotation handle and the first lug on the slide bar of cover in proper order, the bottom of rotatory handle has been seted up, the first lug is fixedly connected with the first lug and the first lug has the first lug and the cylinder has been seted up to the first lug and has the recess, the one side of movable hook is connected with the first lug is close to the cylinder has the one side of the movable hook, the cylinder has been seted up the one side of the recess has the movable hook has the top of the cylinder has been connected with the cylinder has been seted up, the recess has been kept away from the top of the movable hook, the movable claw hook is fixedly connected with a spring below the rotating joint of the protective shell, a third groove capable of limiting the rotary handle is formed in the outer wall of the upper portion of the protective shell, and the rotary handle penetrates through the third groove and extends out of the protective shell.

Preferably, a sealing rubber pad is fixedly connected to the inner wall of the top end of the cavity, and the gas pipe penetrates through the sealing rubber pad and extends into the cavity.

Preferably, the holding down plate sets up the below of detecting the casing, the gas collecting channel has been seted up at the top of holding down plate, the air current inductor is installed to the bottom of gas collecting channel, the holding down plate pass the centre of conveyer belt with one side inner wall of casing is contradicted, one side inner wall of casing is in the top fixedly connected with hydraulic press of third lug, the hydraulic press is used for with unqualified quilt test object follow the conveyer belt pushes down.

Preferably, a plurality of fixing strips are fixedly connected to the outer surface of the conveyor belt.

Preferably, a movable door is rotatably connected to the outer wall of one side of the shell, and the movable door is made of transparent materials.

Preferably, a handle is fixedly connected to one side, away from the bottom of the lower pressing plate, which is abutted against the inner wall of the shell.

Compared with the prior art, the utility model has at least the following beneficial effects:

in the above scheme, through setting up snatch the mechanism, when dismantling and detecting the casing, only need rotate the direction of the rotatory handle on both sides along the third recess, make first lug follow rotatory, thereby the post can follow because the rotation of first lug slides in the spout, make the top of movable claw hook rotate to the direction that is close to protective housing, the bottom of movable claw hook rotates to the direction of keeping away from protective housing, the spring is to keeping away from protective housing's direction tensile, movable claw hook no longer contacts with the second lug this moment, detect the casing just dismantle and accomplish, the benefit of doing so is that need not use other instruments, only need operate rotatory handle alright with detecting the casing dismantlement, simple and fast, operating personnel's time has been saved, make operating personnel dismantlement and installation that operating personnel can be more quick, the change maintenance and daily cleaning of operating personnel to detecting the casing have been made things convenient for.

Through setting up detection casing and holding down plate, when needs are tested the polar plate, as long as place the polar plate after with the membrane electrode assembly on the conveyer belt, the conveyer belt can automatic stop when the test object above the conveyer belt passes through the detection casing, the lifter whereabouts lets the detection casing press on the conveyer belt, cover the test object completely in the cavity, the holding down plate then is used for strengthening the holding strength in the centre of conveyer belt, the gas collecting tank on the holding down plate is pushed down all around, start the test this moment, the air pump passes through the gas-supply pipe to the cavity gas transmission, if the test object is intact, then the air current sensor can not detect the air current, the gas transmission is finished after the one end time, the lifter is with the detection casing mentioning, the conveyer belt continues to start, will be sent out through the transfer port by the test object, if the test object has the condition of leaking, then the air current passes through the test object, the air current sensor detects the air current and triggers the alarm, operating personnel then after the detection casing rise through circuit control hydraulic press, let the output of hydraulic press stretch out, will be tested object follow conveyer belt push away, make the test object drop down along the third lug after setting up, the third bump, can save time, the test is carried out, and the test is carried out fast.

Through setting up the fixed strip, can be more accurate confirm the testing position, to be contradicted by the fixed strip by one side of test target when needs test place on the conveyer belt can, through setting up the dodge gate, can more conveniently observe the test procedure, when the condition that needs to maintain the operation to the casing inside appears, only need open the dodge gate alright operate its inside, made things convenient for operating personnel's maintenance operation, through setting up the handle, make the holding down plate can be more convenient by operating personnel roll-off equipment, improved operating personnel to holding down plate maintenance clear efficiency.

Drawings

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the disclosure and to enable a person skilled in the pertinent art to make and use the disclosure.

FIG. 1 is a schematic perspective view of a leak-proof test apparatus for hydrogen fuel cell plates and membrane electrodes;

FIG. 2 is a schematic cross-sectional perspective view of a first view of a leak-proof testing apparatus for hydrogen fuel cell plates and membrane electrodes;

FIG. 3 is a schematic cross-sectional perspective view of a second view of a leak-proof testing apparatus for hydrogen fuel cell plates and membrane electrodes;

FIG. 4 is a schematic view of a three-dimensional enlarged structure of the grabbing mechanism;

FIG. 5 is a schematic view of a three-dimensional enlarged structure of the gripping mechanism with the protective housing removed;

FIG. 6 is a schematic view of a three-dimensional enlarged structure of the protective housing;

FIG. 7 is a schematic view of a three-dimensional enlarged structure of a first bump;

FIG. 8 is a schematic view of a three-dimensional enlarged structure of the lower platen;

FIG. 9 is a schematic view of an enlarged perspective structure of the assembled detection housing and sealing rubber pad;

fig. 10 is a schematic view of a third bump in a three-dimensional enlarged structure.

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1. A housing; 2. a grabbing mechanism; 3. an air pump; 4. a gas pipe; 5. a detection housing; 6. a lower pressing plate; 7. a conveyor belt; 8. a fixing strip; 9. a hydraulic device; 10. a lifting rod; 11. sealing a rubber pad; 12. a handle; 13. a gas collecting tank; 14. an air flow sensor; 15. a first bump; 16. a protective housing; 17. rotating the handle; 18. a clamping block; 19. a column; 20. a movable claw hook; 21. a movable door; 22. a second bump; 23. a third bump; 24. a slide bar; 25. a connecting block; 26. and a sliding groove.

While particular structures and devices are shown in the drawings to enable a clear implementation of embodiments of the utility model, this is for illustrative purposes only and is not intended to limit the utility model to the particular structures, devices and environments, which may be modified or adapted by those of ordinary skill in the art, as desired, and which remain within the scope of the appended claims.

Detailed Description

The following describes in detail a leak-proof test apparatus for hydrogen fuel cell electrode plates and membrane electrodes provided in the present utility model with reference to the accompanying drawings and specific examples. While the utility model has been described herein in terms of the preferred and preferred embodiments, the following embodiments are intended to be more illustrative, and may be implemented in many alternative ways as will occur to those of skill in the art; and the accompanying drawings are only for the purpose of describing the embodiments more specifically and are not intended to limit the utility model specifically.

It should be noted that references in the specification to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the relevant art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

Generally, the terminology may be understood, at least in part, from the use of context. For example, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense, depending at least in part on the context. In addition, the term "based on" may be understood as not necessarily intended to convey an exclusive set of factors, but may instead, depending at least in part on the context, allow for other factors that are not necessarily explicitly described.

It will be understood that the meanings of "on … …", "over … …" and "over … …" in this disclosure should be interpreted in the broadest sense so that "on … …" means not only "directly on" but also includes meaning "directly on" something with intervening features or layers therebetween, and "over … …" or "over … …" means not only "on" or "over" something, but also may include its meaning "on" or "over" something without intervening features or layers therebetween.

Furthermore, spatially relative terms such as "under …," "under …," "lower," "above …," "upper," and the like may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented and the spatially relative descriptors used herein may similarly be interpreted accordingly.

As shown in fig. 1 to 10, the embodiment of the utility model provides a leak-proof test device for a hydrogen fuel cell polar plate and a membrane electrode, comprising a housing 1, wherein two lifting rods 10 are fixedly connected to the inner wall of the top end of the housing 1, a connecting block 25 is fixedly connected to the bottom of the lifting rods 10, a sliding rod 24 is fixedly connected to the bottom of the connecting block 25, two grabbing mechanisms 2 are arranged on the sliding rod 24, a second bump 22 is clamped below the grabbing mechanisms 2, the bottom of the second bump 22 is fixedly connected to a detection housing 5, a cavity is formed in the bottom of the detection housing 5, an air pump 3 is fixedly connected to the top of the housing 1, an output end of the air pump 3 is fixedly connected to an air pipe 4 penetrating through the housing 1 and the detection housing 5, conveying ports are formed in the outer walls of the two sides of the housing 1 and are penetrated by a conveying belt 7 provided with a plurality of holes, a third bump 23 is fixedly connected to the inner wall of the bottom of the housing 1, the upper part of the third bump 23 is abutted against the lower pressing plate 6, the grabbing mechanism 2 comprises a protective shell 16 and a plurality of movable claw hooks 20, the sliding rod 24 penetrates through the protective shell 16, a rotary handle 17 and a first bump 15 which are sequentially sleeved on the sliding rod 24 are arranged in the protective shell 16, a clamping block 18 is fixedly connected to the bottom of the rotary handle 17, a first groove matched with the clamping block 18 is formed in the top of the first bump 15 and is clamped with the first bump 15, a plurality of inclined sliding grooves 26 are formed in the side wall of the first bump 15, the outer wall of the protective shell 16 is rotationally connected with the movable claw hooks 20, a cylinder 19 is fixedly connected to one surface, close to the protective shell 16, of the upper part of the movable claw hooks 20, a plurality of second grooves penetrated by the cylinder 19 are formed in the outer wall of the protective shell 16, one end, far away from the movable claw hooks 20, of the cylinder 19 is fixedly connected with a ball block and is in sliding connection with the sliding grooves 26, the movable claw hook 20 and the protection casing 16 rotate the below fixedly connected with spring of junction, the third recess that can carry out spacing to rotatory handle 17 is offered to the top outer wall of protection casing 16, rotatory handle 17 runs through the third recess and extends to the protection casing 16 outside, fixedly connected with sealing rubber pad 11 on the top inner wall of cavity, the gas-supply pipe 4 runs through sealing rubber pad 11 and extends to in the cavity, holding down plate 6 sets up in the below that detects casing 5, the gas collecting channel 13 has been offered at the top of holding down plate 6, the air current inductor 14 is installed to the bottom of gas collecting channel 13, holding down plate 6 passes the centre of conveyer belt 7 and contradicts with the one side inner wall of casing 1, one side inner wall of casing 1 is in the top fixedly connected with hydraulic press 9 of third lug 23, hydraulic press 9 is used for pushing down unqualified quilt test object from conveyer belt 7.

Through setting up snatch mechanism 2, when dismantling and detecting casing 5, only need rotate the rotatory handle 17 on both sides along the direction of third recess, make first lug 15 follow rotatory, cylinder 19 can follow and slide in spout 26 owing to the rotation of first lug 15, make the top of movable claw hook 20 rotate to the direction that is close to protective housing 16, the bottom of movable claw hook 20 rotates to the direction that keeps away from protective housing 16, the spring is to keeping away from protective housing 16 direction tensile, movable claw hook 20 no longer contacts with second lug 22 this moment, detect casing 5 just dismantles and accomplishes, the benefit of doing so is that need not use other instruments, only need operate rotatory handle 17 alright with detecting casing 5 dismantlement, the time of operating personnel has been saved, the operating personnel can more quick dismantlement and installation, the change maintenance and the daily cleaning of operating personnel to detecting casing 5 have been made things convenient for.

Through setting up detection casing 5 and holding down plate 6, when needs are tested to the polar plate, as long as place polar plate and membrane electrode after assembling on conveyer belt 7, conveyer belt 7 can automatic stop get off when the test object on conveyer belt 7 passes through detection casing 5, lifter 10 whereabouts lets detection casing 5 press on conveyer belt 7, will be tested the object and cover completely in the cavity, holding down plate 6 then is used for strengthening support intensity in the centre of conveyer belt 7, the gas collecting tank 13 on the holding down plate 6 is pushed down all around, begin the test at this moment, air pump 3 is through gas pipe 4 to the cavity gas transmission, if the test object is good do not leak the condition, then air current inductor 14 can not detect the air current, the gas transmission is finished after one end time, lifter 10 will detect casing 5, conveyer belt 7 continues to start, will be tested the object and be sent out through the transfer port, if the test object has the leak condition, then the air current passes through the test object, air current inductor 14 detects the air current and triggers the alarm, operating personnel then is through circuit control hydraulic pressure 9 in the centre of conveyer belt 7, let the output of hydraulic pressure 9 stretch out the test object 7, it is followed to be tested the object and be tested 7 and be carried out on the third to the conveyer belt 23 can be followed to the slope and the test can be set up, the slope is more convenient to the three is followed to the test and is set up and can be more labour saving and the test is passed down to the test to the slope to be carried out.

As shown in fig. 1-3 and 8, in this embodiment, a plurality of fixing strips 8 are fixedly installed on the outer surface of the conveyor belt 7, a movable door 21 is rotatably connected to the outer wall of one side of the casing 1, the movable door 21 is made of transparent material, a handle 12 is fixedly connected to one side of the bottom of the lower pressing plate 6, which is abutted against the inner wall of the casing 1, is far away from the bottom of the lower pressing plate 6, the fixing strips 8 are arranged, the testing position can be more accurately confirmed, one side of a tested object is abutted against the fixing strips 8 to be placed on the conveyor belt 7 when testing is needed, the testing process can be more conveniently observed through arranging the movable door 21, when the condition that maintenance operation is needed to be performed on the inside of the casing 1 occurs, the inside of the casing 1 can be operated only by opening the movable door 21, so that maintenance operation of operators is facilitated, the lower pressing plate 6 can be more conveniently slid out of the equipment by the operators through arranging the handle 12, and the maintenance and cleaning efficiency of the lower pressing plate 6 by the operators is improved.

According to the technical scheme provided by the utility model, the grabbing mechanism 2 is arranged, when the detection shell 5 is dismounted, only the rotary handles 17 on two sides are required to rotate along the direction of the third groove, so that the first lug 15 rotates in a following manner, the cylinder 19 slides in the sliding groove 26 due to the rotation of the first lug 15, the top of the movable claw hook 20 rotates in the direction close to the protective shell 16, the bottom of the movable claw hook 20 rotates in the direction far away from the protective shell 16, the spring stretches in the direction far away from the protective shell 16, and at the moment, the movable claw hook 20 is not contacted with the second lug 22, so that the detection shell 5 is dismounted.

Through setting up detection casing 5 and holding down plate 6, when needs are tested to the polar plate, as long as place polar plate and membrane electrode after assembling on conveyer belt 7, conveyer belt 7 can automatic stop get off when the test object on conveyer belt 7 passes through detection casing 5, lifter 10 whereabouts lets detection casing 5 press on conveyer belt 7, will be tested the object and cover completely in the cavity, holding down plate 6 then is used for strengthening support intensity in the centre of conveyer belt 7, the gas collecting tank 13 on the holding down plate 6 is pushed down all around, begin the test at this moment, air pump 3 is through gas pipe 4 to the cavity gas transmission, if the test object is good do not leak the condition, then air current inductor 14 can not detect the air current, the gas transmission is finished after one end time, lifter 10 will detect casing 5, conveyer belt 7 continues to start, will be tested the object and be sent out through the transfer port, if the test object has the leak condition, then the air current passes through the test object, air current inductor 14 detects the air current and triggers the alarm, operating personnel then is through circuit control hydraulic pressure 9 in the centre of conveyer belt 7, let the output of hydraulic pressure 9 stretch out the test object 7, it is followed to be tested the object and be tested 7 and be carried out on the third to the conveyer belt 23 can be followed to the slope and the test can be set up, the slope is more convenient to the three is followed to the test and is set up and can be more labour saving and the test is passed down to the test to the slope to be carried out.

Through setting up fixed strip 8, can be more accurate confirm the testing position, to be contradicted by fixed strip 8 by one side of test target when needs test place on conveyer belt 7 can, through setting up dodge gate 21, can more conveniently observe the test procedure, when the condition that needs to carry out maintenance operation to casing 1 inside appears, only need open dodge gate 21 alright operate its inside, the maintenance operation of operating personnel has been made things convenient for, through setting up handle 12, make holding down plate 6 can be more convenient by operating personnel roll-off equipment, the clean efficiency of operating personnel to holding down plate 6 maintenance has been improved.

The utility model is intended to cover any alternatives, modifications, equivalents, and variations that fall within the spirit and scope of the utility model. In the above description of the preferred embodiments of the utility model, specific details are set forth in order to provide a thorough understanding of the utility model, and the utility model will fully be understood to those skilled in the art without such details. In other instances, well-known methods, procedures, flows, components, circuits, and the like have not been described in detail so as not to unnecessarily obscure aspects of the present utility model.

Those of ordinary skill in the art will appreciate that all or a portion of the steps in implementing the methods of the embodiments described above may be implemented by a program that instructs associated hardware, and the program may be stored on a computer readable storage medium, such as: ROM/RAM, magnetic disks, optical disks, etc.

The foregoing is merely a preferred embodiment of the present utility model and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present utility model, which are intended to be comprehended within the scope of the present utility model.

Claims (6)

1. A leak-proof test apparatus for a hydrogen fuel cell electrode plate and a membrane electrode, comprising: the utility model provides a protective hook device, including casing (1), two lifter (10) of top inner wall fixedly connected with of casing (1), the bottom fixedly connected with connecting block (25) of lifter (10), the bottom fixedly connected with slide bar (24) of connecting block (25), install two on slide bar (24) and snatch mechanism (2), the below joint of snatch mechanism (2) has second lug (22), the bottom fixedly connected with of second lug (22) detects casing (5), the cavity has been seted up to the bottom of detecting casing (5), casing (1) top fixedly connected with air pump (3), the output fixedly connected with of air pump (3) runs through casing (1) with detect gas-supply pipe (4) of casing (5), conveyer belt (7) that have seted up a plurality of holes are run through all to the both sides outer wall of casing (1), the bottom inner wall fixedly connected with third lug (23) of casing (1), the top of third lug (23) is contradicted and is pressed down clamp plate (6), including casing (16) and protective hook (16) are snatched in advance, casing (16), the internally mounted of protective housing (16) is overlapped in proper order and is established rotatory handle (17) and first lug (15) on slide bar (24), the bottom fixedly connected with fixture block (18) of rotatory handle (17), first recess and with first lug (15) joint of fixture block (18) looks adaptation are seted up at the top of first lug (15), set up spout (26) of a plurality of slopes on the lateral wall of first lug (15), the outer wall of protective housing (16) with movable claw hook (20) rotate to be connected, the top of movable claw hook (20) is close to one side of protective housing (16) is all fixedly connected with cylinder (19), set up a plurality of by on the outer wall of protective housing (16) the second recess that cylinder (19) run through, one end fixedly connected with ball piece and with spout (26) sliding connection of movable claw hook (20), movable claw hook (20) and housing (16) rotate to the side of holding down, the top of protective housing (16) is equipped with the recess is rotated to the side of holding down, the top of the protective housing (16) is connected with the rotatory side of extension of side of the spring (17).

2. The leak-proof test apparatus for hydrogen fuel cell electrode plate and membrane electrode according to claim 1, wherein a sealing rubber pad (11) is fixedly connected to the inner wall of the top end of the cavity, and the gas pipe (4) extends into the cavity through the sealing rubber pad (11).

3. The leakage prevention test device for the hydrogen fuel cell polar plate and the membrane electrode according to claim 1, wherein the lower pressure plate (6) is arranged below the detection shell (5), a gas collecting groove (13) is formed in the top of the lower pressure plate (6), a gas flow sensor (14) is mounted at the bottom of the gas collecting groove (13), the lower pressure plate (6) passes through the middle of the conveyor belt (7) to be abutted against one side inner wall of the shell (1), a hydraulic device (9) is fixedly connected to one side inner wall of the shell (1) above the third protruding block (23), and the hydraulic device (9) is used for pushing off an unqualified tested object from the conveyor belt (7).

4. The leak-proof test apparatus of hydrogen fuel cell electrode plate and membrane electrode according to claim 1, characterized in that a plurality of fixing strips (8) are fixedly connected to the outer surface of the conveyor belt (7).

5. The leak-proof test apparatus for hydrogen fuel cell electrode plate and membrane electrode according to claim 1, wherein a movable door (21) is rotatably connected to an outer wall of one side of the housing (1), the movable door (21) being a transparent material.

6. The leak-proof test apparatus of hydrogen fuel cell electrode plate and membrane electrode according to claim 1, wherein a handle (12) is fixedly connected to a side of the bottom of the lower pressure plate (6) which is away from the side abutting against the inner wall of the housing (1).