CN116053541A - Fuel cell, fuel cell unit cell and spring plate - Google Patents

Abstract

The embodiment of the invention discloses a fuel cell, a single fuel cell and an elastic sheet. The fuel cell includes a plurality of fuel cell unit cells. The fuel cell unit cell includes: the device comprises a membrane electrode assembly, a gas diffusion layer, a polar plate and an elastic sheet; a plurality of ridges are arranged on one surface of the polar plate facing the gas diffusion layer; the elastic sheet is arranged between the corresponding polar plate and the gas diffusion layer, and the position corresponding to the top surface of the ridge is a protection part; the elastic sheet sequentially comprises three first states, a second state and a third state under the extrusion of the polar plate and the gas diffusion layer; when in the first state, the protection part is of a first arc-shaped structure protruding towards the gas diffusion layer; when in the second state, the protection part is of a second arc-shaped structure which is attached between the top surface of the ridge and the gas diffusion layer; when in the third state, the edge part of the protection part is a fourth arc-shaped structure protruding to the gas diffusion layer, and the fourth arc-shaped structure covers convex angles generated by the deformation of the ridge part. The shell fragment of this application can avoid polar plate to damage gas diffusion layer and membrane electrode assembly.

Description

Fuel cell, fuel cell unit cell and spring plate

Technical Field

The present application relates to the field of batteries, and more particularly, to a fuel cell, a fuel cell unit cell, and a spring.

Background

The fuel cell unit cell comprises a membrane electrode assembly, a gas diffusion layer and a polar plate which are arranged in a stacked manner, wherein a flow field comprising a plurality of gas flow channels is generally arranged on the polar plate, the function of the polar plate is to provide reaction gas (such as hydrogen or air) for electrochemical reaction, and adjacent gas flow channels are separated by ridge parts.

When assembling a fuel cell, it is necessary to stack a plurality of fuel cell unit cells together. In order to ensure close contact between adjacent layer structures, the multilayer structure of the fuel cell needs to be pressed and piled, and the pole plates, the gas diffusion layers and the membrane electrode assemblies of the single cells are extruded in the pressing and piling process, so that gaps are finally reduced or eliminated.

It has been found that membrane electrode assemblies within the fuel cell unit cells are susceptible to breakage after compression stacking. In this regard, the related art is not entirely effective in preventing damage to the membrane electrode by monitoring and controlling the pressure during the press stacking process.

Disclosure of Invention

One of the important points of the invention is that the inventor discovers the important reason for membrane electrode damage during the current fuel cell stack pressing. The inventors have found that the ridge acts as a bulge in the flow field region, in direct contact with the gas diffusion layer and compression occurs. If the pressure distribution of different single cells is uneven during stacking, the pressure of a part of the area is overlarge, and the ridge in the part of the area is easy to slightly deform; local bulges appear on two sides of the width of the deformed ridge, and local pressure generated by the bulges on the gas diffusion layer and the proton exchange membrane can be far greater than a design allowable value, so that the proton exchange membrane is damaged. Based on the findings of the inventors, the present invention proposes a fuel cell and a fuel cell unit cell, which aim to solve the above-mentioned problems existing in the prior art.

In order to achieve the above object, the present invention provides a spring plate for a single cell of a fuel cell, characterized in that,

the elastic sheet is arranged between the polar plate and the gas diffusion layer of the single fuel cell;

a plurality of ridges are arranged on one surface of the polar plate facing the gas diffusion layer;

the elastic sheet comprises a protection part, and the protection part covers the top surface of the ridge;

the elastic sheet comprises three states under the extrusion of the polar plate and the gas diffusion layer:

when no pressure exists, the elastic sheet is in a first state, the protection part in the first state is of a first arc-shaped structure protruding towards the gas diffusion layer, and the gas diffusion layer is in contact with but does not apply force to the elastic sheet; when the pressure is gradually increased within a preset range, the elastic sheet is gradually switched from the first state to the second state, the protection part in the second state is a second arc-shaped structure protruding towards the gas diffusion layer, and the curvature of the second arc-shaped structure is smaller than that of the first arc-shaped structure; when the pressure is increased to exceed a preset range, the elastic sheet is switched from the second state to a third state, the middle part of the protection part in the third state protrudes towards the ridge, and the edge parts of the protection part cover convex angles on two sides of the width of the top surface of the ridge to protect the gas diffusion layer.

In some embodiments, the dome material is metal; the surface of the elastic sheet is a hydrophilic surface.

In some embodiments, the thickness of the intermediate portion is less than the thickness of the edge portion.

In some embodiments, the ridge top surface width is W;

when the elastic sheet is in a first state, the maximum height from the protection part to the top surface of the ridge part is H;

w and H satisfy the following conditions:

0.2W≤H≤0.4W。

in some embodiments, a groove is provided between two adjacent ridges;

the elastic sheet is provided with a concave part between two adjacent protection parts;

the concave part is embedded into the groove part, and two sides are respectively at least partially attached to the side walls of two adjacent ridges.

In some embodiments, the bottom of the recess is separated from the bottom surface of the groove, the bottom of the recess having a plurality of openings.

In some embodiments, at least a portion of the openings are formed using a notching process;

in the gas flow direction of the groove part, the connection part of the punching part and the elastic piece is positioned at the downstream of the opening, and the punching part deflects towards the bottom surface of the groove part.

In some embodiments, the length of the punching portion is less than the distance between the bottom of the recess and the bottom surface of the groove.

In order to achieve the above object, the present invention also provides a fuel cell unit cell comprising:

a membrane electrode assembly;

a gas diffusion layer provided outside the membrane electrode;

a polar plate arranged on one side of the gas diffusion layer far away from the membrane electrode assembly;

the spring as in any one of the above embodiments.

In addition, in order to achieve the above object, the present invention also provides a fuel cell, which is characterized by comprising a plurality of fuel cell single cells according to any one of the foregoing embodiments.

The fuel cell comprises a plurality of fuel cell single cells, wherein a shrapnel which plays a role in protection is arranged between a polar plate and a gas diffusion layer, and the area of the shrapnel corresponding to a ridge is a protection part. The elastic sheet is deformed by the extrusion of the polar plate and the gas diffusion layer during stacking, and has a first state, a second state and a third state; at first, the elastic sheet is in contact with the polar plate and the gas diffusion layer but is not subjected to extrusion force, the elastic sheet is in a first state, and the protection part is of a first arc-shaped structure protruding towards the gas diffusion layer so as to play a role of buffering; when the pressure between the polar plate and the gas diffusion layer is in a reasonable interval, the elastic sheet is in a second state, the protection part is a second arc-shaped structure protruding towards the gas diffusion layer, and the curvature of the second arc-shaped structure is smaller than that of the first arc-shaped structure; when the pressure between the polar plate and the gas diffusion layer is overlarge, the elastic sheet is in a third state, the middle part of the protection part reverses and protrudes towards the ridge, and the edge part of the protection part covers the convex angles at two sides of the width of the top surface of the ridge. Therefore, when the pressure between the plate and the gas diffusion layer is excessively large, the gas diffusion layer and the membrane electrode assembly are not directly in contact with the convex corners of the plate ridge, but in contact with the edge portions of the guard; the contact area of the edge portion of the protection portion is larger than that of the ridge portion convex angle, so that breakage of the gas diffusion layer and the membrane electrode assembly can be avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

The methods, systems, and/or programs in the accompanying drawings will be described further in terms of exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These exemplary embodiments are non-limiting exemplary embodiments, wherein reference numerals represent similar mechanisms throughout the several views of the drawings.

Fig. 1 is a schematic structural diagram of a spring according to some embodiments of the present application;

fig. 2 is a schematic structural view of a fuel cell unit cell according to some embodiments of the present application;

fig. 3 is a schematic structural diagram of a fuel cell unit cell according to some embodiments of the present disclosure when the elastic sheet is in the second state;

fig. 4 is a schematic structural diagram of a fuel cell unit cell according to some embodiments of the present disclosure when the elastic sheet is in the third state;

FIG. 5 is an enlarged view of a portion of FIG. 2;

fig. 6 is a schematic structural diagram of another fuel cell unit cell according to some embodiments of the present disclosure when the elastic sheet is in the first state;

fig. 7 is a schematic structural diagram of another fuel cell unit cell according to some embodiments of the present disclosure when the elastic sheet is in the second state;

fig. 8 is a cross-sectional view of fig. 6 taken along line C-C.

Icon: 10-membrane electrode assembly, 20-gas diffusion layer, 30-polar plate, 31-ridge, 311-lobe, 32-groove, 40-shrapnel, 41-protection part, 411-first arc structure, 412-second arc structure, 413-third arc structure, 414-fourth arc structure, 42-concave part, 421-opening, 422-punching part, 423-connection part, 43-spacing part, 44-connection part.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, as provided in the accompanying drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present application, it should be noted that, if the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like indicate an azimuth or a positional relationship based on that shown in the drawings, or an azimuth or a positional relationship that a product of the application conventionally puts in use, it is merely for convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like in the description of the present application, if any, are used for distinguishing between the descriptions and not necessarily for indicating or implying a relative importance.

Furthermore, the terms "horizontal," "vertical," and the like in the description of the present application, if any, do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present application, it should also be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" should be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.

Referring to fig. 1, the elastic sheet 40 located in the XY plane is now described, the elastic sheet 40 of the present embodiment includes a plurality of parallel arranged protecting portions 41, a spacing portion 43 located between two adjacent protecting portions 41, and connecting portions 44 located at two ends of the protecting portions 41; the connection portion 44 connects the plurality of protection portions 41 to form a single body.

Referring to fig. 2, a section of a flow field region of a fuel cell unit cell in an XZ plane is illustrated, and the fuel cell unit cell of the present embodiment includes: the membrane electrode assembly 10, two gas diffusion layers 20, two polar plates 30 and two elastic sheets 40.

The membrane electrode assembly 10 includes a proton exchange membrane and catalytic layers (not shown) disposed on both sides of the proton exchange membrane. The two gas diffusion layers 20 are bonded to the catalytic layers of the membrane electrode assembly 10 from both sides.

The two electrode plates 30 are the cathode and anode plates of the fuel cell, respectively. The two electrode plates 30 are respectively disposed on one side of the two gas diffusion layers 20 away from the membrane electrode assembly 10, and a plurality of ridges 31 are disposed on a side facing the gas diffusion layers 20. A groove 32 is formed between two adjacent ridges 31, the groove 32 is used as a gas flow channel for the flow of the reaction gas, and the area where the groove 32 and the ridge 31 are located is the flow field area. When the fuel cell unit cell is operated, part of the reaction gas enters the corresponding gas diffusion layer 20 from the groove portion 32, and finally reaches the catalytic layer of the membrane electrode assembly 10 to perform electrochemical reaction.

The two spring plates 40 are respectively disposed between the corresponding electrode plate 30 and the gas diffusion layer 20, the protecting portion 41 covers the top surface of the ridge portion 31, the spacing portion 43 is located on the groove portion 32, the spacing portion 43 is a void without solid material so as to facilitate the gas passing, the width of the protecting portion 41 may be slightly larger than the width of the top surface of the ridge portion 31, and correspondingly, the width of the spacing portion 43 may be slightly smaller than the width of the groove portion 32.

As an alternative, the protecting portions 41 and the spacing portions 43 of the spring 40 are laid in the flow field area of the plate 30, and the connecting portions 44 are located outside the flow field area, and all the protecting portions 41 can cover all the ridges 31 of the plate 30 in a one-to-one correspondence.

Further, as an alternative, the polar plate 30 and the connection part 44 are provided with positioning structures, such as positioning protrusions and positioning grooves, which are matched with each other, and the connection part 44 is located outside the flow field area, so that the positioning structures cannot block the reaction gas. The positioning structure can fix the relative position between the polar plate 30 and the elastic sheet 40, so that the protecting part 41 can always cover the top surface of the ridge part 31 in the stacking process.

The cathode plate and the anode plate may have similar structures in this application, and the two gas diffusion layers 20 and the two spring plates 40 may also have similar structures, respectively. Therefore, in order to highlight the detailed features, the description will be given hereinafter only with respect to the membrane electrode assembly 10 and the gas diffusion layer 20, the electrode plate 30, and the spring plate 40 on one side thereof, and it will be understood that these descriptions are equally applicable to the gas diffusion layer 20, the electrode plate 30, and the spring plate 40 on the other side.

Referring to fig. 2 to 4, the spring 40 in the present embodiment includes three states in sequence under the compression of the polar plate 30 and the gas diffusion layer 20: fig. 2 is a schematic structural view of the elastic sheet 40 of the fuel cell unit cell in the embodiment of the present application in the first state; fig. 3 is a schematic structural view of the elastic sheet 40 of the fuel cell unit cell in the embodiment of the present application in the second state; fig. 4 is a schematic structural view of the spring 40 of the fuel cell unit cell in the embodiment of the present application in the third state.

As shown in fig. 2, at the beginning, the spring 40 is in contact with the electrode plate 30 and the gas diffusion layer 20, but the spring 40 is not pressed by the electrode plate 30 and the gas diffusion layer 20, at this time, the spring 40 is in the first state, the protection portion 41 is a first arc structure 411 protruding toward the gas diffusion layer 20, and the gas diffusion layer 20 is in contact with but does not apply force to the protection portion 41.

As shown in fig. 3, as the press stack proceeds, the spring 40 is deformed by the co-extrusion of the electrode plate 30 and the gas diffusion layer 20, and the first arc-shaped structure 411 of the protection portion 41 is gradually flattened. When the pressure between the polar plate 30 and the gas diffusion layer 20 is within the preset reasonable interval range, the protecting part 41 becomes a second arc structure 412 protruding towards the gas diffusion layer 20, the curvature of the second arc structure 412 is smaller than that of the first arc structure 411, at this time, the elastic sheet 40 is in the second state, the contact area between the polar plate 30 and the gas diffusion layer 20 is large, the pressure distribution is uniform, and the damage to the gas diffusion layer 20 and the membrane electrode assembly 10 is not caused.

As shown in fig. 4, when the pressure is further increased until the preset reasonable interval range is exceeded, the ridge 31 of the plate 30 is deformed: the top surface of the ridge 31 is slightly recessed in the middle, and the width of the ridge is formed with convex corners 311 facing the gas diffusion layer 20. The elastic sheet 40 in this embodiment also deforms correspondingly when the pressure exceeds a reasonable range: the middle part of the protecting part 41 is reversely protruded under the action of pressure to form a third arc-shaped structure 413 protruded to the ridge part 31; the edge portion of the protection portion 41 has the same convex direction as in the first and second states, that is, forms a fourth arc-shaped structure 414 protruding toward the gas diffusion layer 20; the two fourth arc structures 414 cover the two convex corners 311 of the ridge 31 respectively, and the spring 40 is in the third state.

In this embodiment, the first state and the third state of the elastic sheet 40 are both stable states, i.e. after the pressure is removed, the elastic sheet 40 can still maintain the existing state; the second state of the elastic sheet 40 is an unstable state, and after the pressure is removed, the elastic sheet 40 is restored to the first state; when the pressure applied to the middle portion of the protection portion 41 exceeds a critical value (i.e., the upper limit of the reasonable section), the elastic piece 40 is switched from the second state to the third state.

It will be appreciated that in the absence of the dome 40, if the pressure exceeds a reasonable level, the lobes 311 would directly contact the gas diffusion layer 20, causing local pressure at the gas diffusion layer 20 and the mea 10 to surge thereat and exceed the design value, and the lobes 311 would "puncture" the gas diffusion layer 20 and the mea 10.

In the present embodiment, when the elastic sheet 40 is in the third state, the curvature of the fourth arc structure 414 is smaller than that of the convex corner 311, so the contact area between the gas diffusion layer 20 and the fourth arc structure 414 is larger than that between the gas diffusion layer 20 and the convex corner 311. The local pressure when the gas diffusion layer 20 contacts the fourth arc structure 414 in the third state is slightly increased, but still less than the design value, compared to the second state, so that the probability of breakage of the gas diffusion layer 20 and the membrane electrode assembly 10 can be reduced.

As an alternative, the material of the elastic sheet 40 is metal, so that the contact resistance between the polar plate 30, the elastic sheet 40 and the gas diffusion layer 20 can be reduced; the surface of the elastic sheet 40 is a hydrophilic surface, so that water generated by the fuel cell can be quickly dispersed along the surface of the elastic sheet 40 after reaching the elastic sheet 40 through the gas diffusion layer 20, and then is discharged along with the flowing of the reaction gas.

Referring to fig. 5, fig. 5 is an enlarged view of the area B in fig. 2, and in some embodiments, the thickness d1 of the middle portion of the protecting portion 41 is smaller than the thickness d2 of the edge portion, so that the spring 40 can smoothly enter the third state when bearing the pressure beyond a reasonable range. When the elastic sheet 40 is switched from the second state to the third state under the action of pressure, the middle part is thinner, so that the elastic sheet is more easily deformed until reversely protruding under the extrusion of the gas diffusion layer 20; the edge portion is thicker, so that the edge portion is prevented from being greatly deformed by the extrusion of the convex angle 311, and thus the fourth arc structure 414 is formed to function as a protection for the gas diffusion layer 20 and the membrane electrode assembly 10.

In some embodiments, as shown in fig. 5, the width of the top surface of the ridge portion 31 is W, and when the elastic sheet 40 is in the first state, the maximum height from the protecting portion 41 to the top surface of the ridge portion 31 is H, where W and H satisfy the condition: h is more than or equal to 0.2W and less than or equal to 0.4W. If the height H is too large, the protection portion 41 of the spring 40 in the first state is too protruding compared with the top surface of the ridge 31, so that when the spring 40 is pressed into the second state, the protection portion 41 is attached between the top surface of the ridge 31 and the gas diffusion layer 20 in a larger curvature state, thereby increasing the contact resistance between the polar plate 30, the spring 40 and the gas diffusion layer 20 and reducing the power generation efficiency of the fuel cell. If the height H is too small, the deformation margin of the elastic sheet 40 is insufficient, so that the elastic sheet 40 cannot enter the third state, or when the elastic sheet 40 is in the third state, the curvature radius of the fourth arc structure 414 is too small, and further the contact area between the fourth arc structure 414 and the gas diffusion layer 20 is also reduced, the local pressure between the two is increased, and finally the elastic sheet 40 can damage the gas diffusion layer 20 and the membrane electrode assembly 10.

As shown in fig. 6, in some embodiments, the spacer 43 between two adjacent guard portions 41 and without solid material is replaced with a recess 42 having solid material. After assembly, the recess 42 is embedded in the groove 32 of the plate 30, and two sides of the recess 42 are respectively attached to the side walls of two adjacent ridges 31. Since the protecting portion 41 needs to completely cover the ridge portion 31, the width of the protecting portion 41 is larger than the width of the ridge portion 31, and in this condition, in order to enable both sides of the recess portion 42 to better fit the side walls of the ridge portion 31, the cross section of the ridge portion 31 may be a trapezoid with a narrow upper portion and a wide lower portion in this embodiment. In this embodiment, the concave portion 42 connects two adjacent protecting portions 41, so as to enhance the structural strength of the elastic sheet 40, and avoid the elastic sheet 40 from being damaged during the processing, transportation and assembly processes; in addition, the present embodiment can fix the elastic sheet 40 in the X direction in fig. 6 by means of the mating relationship between the recess 42 and the groove 32, that is, fix the elastic sheet 40 in the direction perpendicular to the extending direction of the groove 32, so as to avoid the dislocation of the protection portion 41 and the top surface of the ridge 31 during stacking.

Alternatively, the bottom of the recess 42 is separated from the bottom surface of the groove 32, i.e., the bottom of the recess 42 is spaced from the bottom surface of the groove 32. In this embodiment, the recess 42 not only can play a role of fixing, but also can serve as a buffer area when the spring 40 switches states. As shown in fig. 7, when the elastic piece 40 is switched from the first state to the second state, the protection portion 41 is changed from the first arc-shaped structure 411 to the second arc-shaped structure 412, and at this time, the bottom of the recess portion 42 is bent to absorb the portion where the deformation of the protection portion 41 is reduced. Further, the bottom of the recess 42 has a plurality of openings 421; in this embodiment, the recess 42 divides the slot 32 into two upper and lower regions, and the opening 421 can communicate the two regions, so that the reactant gas in the lower region of the slot 32 can flow into the gas diffusion layer 20, and the water drops generated by the gas diffusion layer 20 can enter the lower region of the slot 32 to accelerate the discharge.

Referring to fig. 6 and 8, fig. 8 is a cross-sectional view taken along line C-C of fig. 6, and in some embodiments, at least a portion of the opening 421 is formed by a notching process. The direction indicated by the short-line arrow in fig. 8 (i.e., the Y-axis forward direction) is the gas flow direction of the groove 32, and the junction 423 of the punching portion 422 and the elastic piece 40 is located downstream of the opening 421, and the punching portion 422 deflects toward the bottom surface of the groove 32. In this embodiment, the elastic sheet 40 may be obtained by punching, and the bottom of the recess 42 is partially punched to form the opening 421. The punched out portion 422 is not completely separated from the elastic sheet 40, but is deflected from the connection portion 423 toward the bottom surface of the groove 32, and the flow of the gas in the region below the groove 32 is disturbed. Since the junction 423 is located downstream of the opening 421, the gas, after being blocked by the flushing portion 422, may be diverted to flow through the opening 421 to the region above the trough 32, thereby increasing the rate at which the gas enters the gas diffusion layer 20 and improving the gas utilization.

Further, the length of the punched portion 422 is smaller than the distance between the bottom of the recess 42 and the bottom surface of the groove 32, i.e. the length of the punched portion 422 is smaller than the distance from the connection 423 to the bottom surface of the groove 32. In this embodiment, when the elastic sheet 40 is assembled with the polar plate 30 and when the state of the elastic sheet 40 is switched in the stacking process, the length of the punching portion 422 is always smaller than the distance from the connection portion 423 to the bottom surface of the slot portion 32, i.e. the punching portion 422 will not contact the bottom surface of the slot portion 32, so as to avoid the situation that the connection portion 423 is broken due to the extrusion of the slot portion 32 to the punching portion 422.

Some embodiments of the present application relate to a fuel cell comprising a plurality of fuel cell units, current collector plates, end plates as in any of the previous embodiments. The fuel cells are stacked in sequence, the current collecting plate is used for collecting current generated by the fuel cells, the number of the end plates is two, and the two end plates are matched and fixedly connected through the anchoring piece so as to connect the functional components such as the fuel cells, the current collecting plate and the like into a whole.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims (10)

1. A spring plate for a single fuel cell is characterized in that,

the elastic sheet is arranged between the polar plate and the gas diffusion layer of the single fuel cell;

a plurality of ridges are arranged on one surface of the polar plate facing the gas diffusion layer;

the elastic sheet comprises a protection part, and the protection part covers the top surface of the ridge;

the elastic sheet comprises three states under the extrusion of the polar plate and the gas diffusion layer:

when no pressure exists, the elastic sheet is in a first state, the protection part in the first state is of a first arc-shaped structure protruding towards the gas diffusion layer, and the gas diffusion layer is in contact with but does not apply force to the elastic sheet; when the pressure is gradually increased within a preset range, the elastic sheet is gradually switched from the first state to the second state, the protection part in the second state is a second arc-shaped structure protruding towards the gas diffusion layer, and the curvature of the second arc-shaped structure is smaller than that of the first arc-shaped structure; when the pressure is increased to exceed a preset range, the elastic sheet is switched from the second state to a third state, the middle part of the protection part in the third state protrudes towards the ridge, and the edge parts of the protection part cover convex angles on two sides of the width of the top surface of the ridge to protect the gas diffusion layer.

2. The spring of claim 1, wherein the spring material is metal; the surface of the elastic sheet is a hydrophilic surface.

3. The spring of claim 1, wherein the thickness of the intermediate portion is less than the thickness of the edge portion.

4. The spring of claim 1, wherein the ridge top surface has a width W;

when the elastic sheet is in a first state, the maximum height from the protection part to the top surface of the ridge part is H;

w and H satisfy the following conditions:

0.2W≤H≤0.4W。

5. the spring of claim 1, wherein a groove is provided between two adjacent ridges;

the elastic sheet is provided with a concave part between two adjacent protection parts;

the concave part is embedded into the groove part, and two sides are respectively at least partially attached to the side walls of two adjacent ridges.

6. The spring of claim 5, wherein the bottom of the recess is separated from the bottom surface of the groove, and the bottom of the recess has a plurality of openings.

7. The spring of claim 6, wherein at least a portion of the openings are formed by a notching process;

in the gas flow direction of the groove part, the connection part of the punching part and the elastic piece is positioned at the downstream of the opening, and the punching part deflects towards the bottom surface of the groove part.

8. The spring of claim 7, wherein the length of the punched out portion is less than the distance between the bottom of the recess and the bottom surface of the groove.

9. A single fuel cell, comprising:

a membrane electrode assembly;

a gas diffusion layer provided outside the membrane electrode;

a polar plate arranged on one side of the gas diffusion layer far away from the membrane electrode assembly;

a dome according to any one of claims 1 to 8.

10. A fuel cell comprising a plurality of fuel cell single cells according to claim 9.

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