CN114420964B - Injection molding method of metal bipolar plate for fuel cell and its seal - Google Patents

Abstract

The invention provides a metal bipolar plate for a fuel cell and an injection molding method of a sealing member of the metal bipolar plate for the fuel cell, wherein the metal bipolar plate for the fuel cell realizes the injection molding of a sealing agent based on a cathode plate and an anode plate with different sizes, and solves the technical problem of abnormal deformation of the metal bipolar plate possibly caused by the sealing member of the metal bipolar plate in the injection molding process.

Description

Injection molding method of metal bipolar plate for fuel cell and its seal

technical field

The present invention relates to the technical field of fuel cells, in particular to a metal bipolar plate for fuel cells. The present invention still further relates to an injection molding method for a sealing member of a metal bipolar plate of a fuel cell.

Background technique

A fuel cell is a power generation device that converts chemical energy in a fuel into electrical energy through an electrochemical reaction, and includes a plurality of stacked fuel cell cells, wherein each fuel cell cell includes a cathode plate, an anode plate, and a clamp. A membrane electrode assembly is provided between the cathode plate and the anode plate. In order to ensure the normal operation of the fuel cell, the anode flow field formed between the anode plate and the membrane electrode assembly and the cathode flow field formed between the cathode plate and the membrane electrode assembly should be relative to The external environment is sealed to prevent the leakage of fuel (hydrogen) and/or oxidant (oxygen or air) to the outside and affect the normal reaction. Therefore, it is necessary to provide seals in the sealing portion of the reaction side of the cathode plate (the side of the cathode plate facing the MEA) and the sealing portion of the reaction side of the anode plate (the side of the anode plate facing the MEA), respectively. Parts to achieve the surrounding sealing of the cathode and anode flow fields respectively.

At present, there are mainly three ways to set the seals. The first one is to directly attach the formed seals to the sealing parts of the reaction sides of the cathode and anode plates, but the operation is complicated and it is inconvenient for subsequent electrical Stack assembly; the second is the way of dispensing, through the dispensing machine (dispensing machine or glue applicator), the fluid sealant is dripped and coated on the sealing part of the reaction side of the cathode and anode plates, but the glue is dispensed. It is difficult to precisely control the amount of glue dispensed at the beginning and end of the path. After the seal is formed, the thickness at the junction of the beginning and the end is often too thick or too thin; the third is the method of injection (injection molding of the seal). , filling the fluid sealant in the form of injection into the sealing parts of the reaction sides of the cathode and anode plates through a mold, and forming a seal after the fluid sealant is shaped.

Moreover, with the development of the fuel cell industry, the above-mentioned method of injection (injection molding of seals) is the preferred method in mass production, especially on both sides of the bipolar plate of the fuel cell (the reaction of the cathode plate). The method of simultaneously injecting glue on the side and the reaction side of the anode plate is a key research and development direction. After both sides of the bipolar plates are injected with glue at the same time, the fuel cell stack can be assembled by sandwiching a membrane electrode assembly between two adjacent bipolar plates. It will be appreciated that the bipolar plate comprises a cathode plate and an anode plate that are glued or welded together, with the cooling side of the cathode plate (the backside of the reaction side of the cathode plate) facing the cooling side of the anode plate (the back side of the reaction side of the anode plate), a cooling liquid flow field is formed between the cooling side of the cathode plate and the cooling side of the anode plate.

An existing method of injecting glue on both sides of a metal bipolar plate at the same time enables the sealing member to be integrally formed on both sides of the metal bipolar plate, and the seals are respectively placed on the sealing portion of the metal bipolar plate through a mold. The fluid sealant is injected on both sides of the metal bipolar plate at the same time, because it is difficult to control the pressure of the fluid sealant on the two sides of the metal bipolar plate to be exactly the same, which easily causes the sealing part of the metal bipolar plate to protrude to one side under the action of pressure. , thus affecting the flatness of the entire bipolar plate. In order to solve the above technical problems, a solution for realizing double-sided glue injection of a metal bipolar plate is proposed by providing a number of through holes, wherein the through holes penetrate the metal bipolar plate, and the penetration holes The holes penetrate both the cathode plate of the metal bipolar plate and the anode plate of the metal bipolar plate. During the double-side glue injection process of the metal bipolar plate, the fluid sealant can flow from one side of the metal bipolar plate to the other side through the penetration hole, because the penetration hole will connected, the pressure of the fluid sealant on both sides to the metal bipolar plate is the same, thereby solving the above technical problem.

However, the above technical solution also creates another technical problem. As shown in Figure 1, during the glue injection process, the fluid sealant may flow into between the cathode plate and the anode plate of the metal bipolar plate through the penetration hole under the action of pressure, destroying the pre-assembled The structure formed by the cathode plate and the anode plate even causes the areas where the cathode plate and the anode plate are partially bonded or welded together to separate from each other. The existing solution to the above problem is to weld or bond the cathode and anode plates at the edges where the through holes are formed, so that the fluid sealant cannot flow into the space between the cathode plate and the anode plate through the through holes. between. However, the above-mentioned processing technology for welding or bonding the edges of the penetrating holes of the cathode and anode plates is complicated, requires high precision, is difficult to operate, and is expensive.

SUMMARY OF THE INVENTION

The main advantage of the present invention is to provide a metal bipolar plate for a fuel cell, which realizes the injection molding of the sealant based on the cathode plate and the anode plate of different sizes, and solves the problem that the sealant of the metal bipolar plate is The technical problem of abnormal deformation of the metal bipolar plate that may be caused during the injection molding process (the double-sided glue injection process of the metal bipolar plate). What is particularly valuable is that the inventive concept of the different sizes of the cathode and anode plates of the metal bipolar plate used in the fuel cell of the present invention overcomes the technical prejudice that the size of the cathode plate and the anode plate in the traditional metal bipolar plate should be the same. .

Another advantage of the present invention is to provide a metal bipolar plate for a fuel cell, wherein the metal bipolar plate comprises a first electrode plate and a second electrode plate (one is a cathode plate) which are bonded or welded together with each other , the other is an anode plate), wherein the size of the first electrode plate is larger than the size of the second electrode plate, and the penetration holes of the metal bipolar plate are formed in the enlarged edge portion of the first electrode plate , wherein the penetrating hole only penetrates the first pole plate of the metal bipolar plate, and the penetrating hole is staggered from the second pole plate, so as to ensure the smoothness of the penetrating hole and allow While the fluid sealant flows from one side of the metal bipolar plate to the other side through the penetration hole, the fluid sealant is prevented from flowing into the cathode plate and the metal bipolar plate through the penetration hole. between the anode plates.

Another advantage of the present invention is to provide an injection molding method for a sealing member of a metal bipolar plate, which can make the sealing member integrally molded on both sides of the metal bipolar plate, and can balance the fluid sealant The pressure on both sides of the metal bipolar plate further prevents the fluid sealant from flowing between the cathode and anode plates of the metal bipolar plate.

Other objects and features of the present invention can be fully embodied by the following detailed description and can be realized by combinations of means and means in the detailed description.

Accordingly, according to the present invention, a metal bipolar plate for a fuel cell having at least one of the aforementioned advantages includes:

A first pole plate, wherein the first pole plate comprises an overlapping portion and a flared portion, wherein the enlarged edge portion extends outward from the overlapping portion, wherein the overlapping of the first pole plate The portion forms a reaction side and a cooling side opposite the reaction side of the overlapping portion; and

A second pole plate, wherein the second pole plate forms a reaction side and a cooling side opposite to the reaction side of the second pole plate, wherein the size of the second pole plate is the same as that of the first pole plate. The size of the overlapping portion of the pole plates is the same, wherein the second pole plate is fixedly arranged on the overlapping portion of the first pole plate, wherein the cooling side of the second pole plate is facing the first pole plate. The cooling side of the overlapping portion of a pole plate, so that the second pole plate overlaps the overlapping portion of the first pole plate and the second pole plate is overlapped with the first pole plate. The expanded edges of the plates are staggered from each other;

Wherein, the metal bipolar plate has a plurality of penetrating holes for the fluid sealant to circulate, wherein the penetrating holes are all arranged in the enlarged edge of the first electrode plate to prevent the penetrating holes blocked by the second plate.

In particular, the metal bipolar plate further includes a sealing member, wherein the sealing member includes a first sealing part, a second sealing part and a plurality of connecting parts, wherein the first sealing part is provided on the metal bipolar On the first side of the plate, the second sealing portion is arranged on the second side of the metal bipolar plate, and the connecting portion passes through the corresponding penetration hole, wherein the first sealing portion, the The second sealing portion and the connecting portion are integrally formed.

In one embodiment, the edge of the second pole plate is completely welded or bonded to the first pole plate.

In another embodiment, the edge of the second pole plate is partially welded or bonded to the first pole plate.

Correspondingly, the flow field sealing portion of the second sealing portion is arranged on the edge-flaring portion of the first electrode plate and the second electrode plate, and the flow field sealing portion is formed from the first electrode plate. The flared portion extends to the second electrode plate.

Correspondingly, the flow field sealing portion of the second sealing portion is provided only on the flared portion of the first electrode plate, and the flow field sealing portion and the second electrode plate are spaced apart from each other.

In particular, one of the first electrode plate and the second electrode plate is a cathode plate, and the other is an anode plate.

According to another aspect of the present invention, the present invention further provides an injection molding method for a sealing member of a metal bipolar plate, which comprises the following steps:

S1, prepare a first pole plate and a second pole plate, wherein the size of the first pole plate is larger than the size of the second pole plate, wherein the first pole plate includes a superimposed portion and an enlarged edge portion, wherein the The widening portion extends outward from the overlapping portion, wherein the size of the second pole plate is the same as the overlapping portion of the first pole plate, wherein the overlapping portion of the first pole plate forms a reaction side and a cooling side opposite to the reaction side of the overlapping portion, the second pole plate forms a reaction side and a cooling side opposite the reaction side of the second pole plate;

S2. The second pole plate is fixedly arranged on the overlapping portion of the first pole plate, wherein the cooling side of the second pole plate is facing the part of the overlapping portion of the first pole plate. the cooling side;

S3. Place the fixed first electrode plate and the second electrode plate in a mold, and inject fluid sealant to one side or both sides of the metal bipolar plate through the mold, wherein the fluid the encapsulant can flow from one side of the metal bipolar plate to the other side through the through holes of the metal bipolar plate; and

S4. After the fluid sealant is cured to form the seal, the mold is demolded.

In particular, before the step S3, it also includes the steps:

A plurality of the penetration holes are opened in the enlarged edge portion of the first electrode plate.

In particular, the step S2 further includes the following steps:

Welding or bonding the edge of the second pole plate to the first pole plate.

The foregoing and other advantages of the present invention will be fully realized in conjunction with the following description and accompanying drawings.

The foregoing and other advantages and features of the present invention are fully demonstrated by the following detailed description of the invention and the accompanying drawings.

Description of drawings

Figure 1 shows the shortcomings of a current injection molding method (gluing method) in which the seal is integrally formed on both sides of the metal bipolar plate, which highlights the possibility of fluid sealant flowing through the penetration hole and flowing into the metal bipolar plate. between the cathode plate and the anode plate of the metal bipolar plate.

FIG. 2 is a schematic plan view of a second side of a metal bipolar plate for a fuel cell, with seals of the metal bipolar plate hidden in the drawing, according to an embodiment of the present invention.

3 is a schematic plan view of the reaction side of the first plate of the metal bipolar plate according to an embodiment of the present invention.

4 is a schematic plan view of the reaction side of the second plate of the metal bipolar plate according to an embodiment of the present invention.

5 is a schematic plan view of the second side of the metal bipolar plate according to an embodiment of the present invention, showing the second sealing portion of the sealing member.

6 is a schematic cross-sectional view of a metal bipolar plate according to an embodiment of the present invention, which shows a molding step of the sealing member of the metal bipolar plate, and the cross-sections of the first electrode plate and the second electrode plate in the figure Schematic section only.

7 is a schematic cross-sectional view of a metal bipolar plate according to another embodiment of the present invention, which shows another forming step of the sealing member of the metal bipolar plate, the first electrode plate and the second electrode plate in the figure The section shown is only a schematic section.

FIG. 8 is a flowchart of a method for injection molding a seal of a metal bipolar plate according to an embodiment of the present invention.

Detailed ways

The following description is provided to enable those of ordinary skill in the art to practice the present invention. Other obvious alternatives, modifications and variations will occur to those of ordinary skill in the art. Accordingly, the scope of protection of the present invention should not be limited by the exemplary embodiments described herein.

It should be understood by those of ordinary skill in the art that, unless otherwise specified herein, the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in In other embodiments, the number of the elements may be multiple.

It will be understood by those of ordinary skill in the art that the terms "portrait", "landscape", "upper", "lower", "front", "rear", "left", "right", "vertical", unless otherwise specified herein. "," "horizontal", "top", "bottom", "inside", "outside", etc. refer to the orientation or position based on the orientation or position shown in the drawings, which are only for the convenience of describing the present invention, not Indicates or implies that the device or element involved must have a particular orientation or location. Therefore, the above-mentioned terms should not be construed as limiting the present invention.

2 to 6 of the accompanying drawings, a metal bipolar plate for a fuel cell according to an embodiment of the present invention is illustrated. As shown in Fig. 2 to Fig. 6 of the description, the metal bipolar plate includes a first electrode plate 1 and a second electrode plate 2, wherein the first electrode plate 1 and the second electrode plate 2 are welded by welding Or they are fixedly arranged together by means of bonding or the like. It can be understood that one of the first electrode plate 1 and the second electrode plate 2 is a cathode plate, and the other is an anode plate. In other words, when the first electrode plate 1 is a cathode plate, the second electrode plate 2 is an anode plate, and when the first electrode plate 1 is an anode plate, the second electrode plate 2 is a cathode plate plate.

As shown in FIGS. 2 to 6 of the description, the first electrode plate 1 and the second electrode plate 2 of the metal bipolar plate for a fuel cell according to the embodiment of the present invention both have a reaction side and a cooling side. 3 is a schematic plan view of the reaction side of the first electrode plate 1, the back side of the first electrode plate 1 is the cooling side of the first electrode plate 1, the first electrode plate 1 The reaction side and the cooling side are opposite each other. 4 is a schematic plan view of the reaction side of the second pole plate 2, the back side of the second pole plate 2 is the cooling side of the second pole plate 2, and the reaction side of the second pole plate 2 and the cooling side opposite each other. FIG. 2 is a schematic plan view of one side of the metal bipolar plate, wherein the cooling side of the first electrode plate 1 faces the cooling side of the second electrode plate 2 . As shown in FIG. 2 to FIG. 6 of the description, the first electrode plate 1 of the metal bipolar plate for fuel cells according to the embodiment of the present invention includes a superimposed part 11 and a widening part 12 , wherein the widening part The portion 12 extends outward from the overlapping portion 11, thereby forming the outer edge of the first pole plate 1, wherein the size of the second pole plate 2 is the same as that of the overlapping portion 11 of the first pole plate 1. have the same size, wherein the second pole plate 2 is fixedly arranged on the overlapping portion 11 of the first pole plate 1 , and the cooling side of the second pole plate 2 is facing the first pole plate 1 described overlapping portion 11, so that the second pole plate 2 is overlapped on the overlapping portion 11 of the first pole plate 1 and the second pole plate 2 and the first pole plate 1 The flared portions 12 are staggered from each other. In other words, the overlapping portion 11 of the second electrode plate 2 and the first electrode plate 1 of the metal bipolar plate used in the fuel cell of the present invention constitutes a stacked structure, and the second electrode plate 2 and The widening portions 12 of the first electrode plate 1 are staggered from each other, so that both sides of the widening portion 12 of the first electrode plate 1 are exposed.

Further, in order to balance the fluid sealant on both sides of the metal bipolar plate during the injection molding process of the sealing member 3 of the metal bipolar plate (the double-sided glue injection process of the metal bipolar plate). pressure, the metal bipolar plate is also provided with a plurality of through holes 120 for circulating fluid sealant, wherein the through holes 120 are all arranged in the enlarged edge portion 12 of the first polar plate 1, The penetration hole 120 only penetrates the first electrode plate 1 of the metal bipolar plate. In addition, both sides of the enlarged edge portion 12 of the first electrode plate 1 are exposed, so the penetration holes 120 can be unblocked and not blocked by the second electrode plate 2 . Correspondingly, when the fluid sealant flows from one side of the first electrode plate 1 to the other side of the first electrode plate 1 through the penetration hole 120 , the fluid sealant does not interact with the first electrode plate 1 . One electrode plate 1 and the second electrode plate 2 are in direct contact with the overlapping portion, so as to ensure that the fluid sealant can smoothly pass through the penetration hole 120 to flow from one side of the metal bipolar plate to the other. At the same time, the fluid sealant can also be prevented from flowing (or infiltrating) between the first electrode plate 1 and the second electrode plate 2 of the metal bipolar plate during passing through the penetration hole 120 . In other words, since the fluid sealant flows from one side to the other side of the metal bipolar plate for a fuel cell of the present invention, it only contacts and makes only the first electrode plate 1 Under the pressure of the fluid sealant, the fluid sealant is prevented from flowing into between the first electrode plate 1 and the second electrode plate 2 of the metal bipolar plate through the penetration hole 120 . In addition, the size of the first electrode plate 1 is larger than the size of the second electrode plate 2, which also makes it easier to seal the part between the first electrode plate 1 and the second electrode plate 2 exposed to the fluid sealant (e.g. welding or adhesive sealing).

For a long time, the bipolar plates used in fuel cells, whether they are graphite bipolar plates or metal bipolar plates, are always set to have the same size and outer contour shape in order to facilitate the precise alignment of the cathode and anode plates ( The size and shape of the outer contour of the cathode and anode plates are the same). Although this habitual design has undeniable advantages, it has gradually become a shackle that restricts the innovative design of bipolar plates, leading the technicians in the field of fuel cells to not consider that the cathode and anode plates of different sizes will be used in solving other technical problems. The technical advantages that come, hinder the research and development of technicians in this direction. However, the present invention overcomes the technical prejudice that the cathode and anode plates should have the same size, adopts the technical means (cathode and anode plates of different sizes) that are discarded due to the technical prejudice, and proposes a new method based on the technical means. The technical solution is to solve the technical problem of abnormal deformation of the metal bipolar plate that may be caused during the injection molding process (the double-side glue injection process of the metal bipolar plate) of the sealing member 3 of the metal bipolar plate. This is a particularly rare feature of the metal bipolar plates of the present invention for use in fuel cells.

In combination with the above description and accompanying drawings 6 and 7 of the present invention, the metal bipolar plate further includes the sealing member 3 , wherein the sealing member 3 includes a first sealing part 31 , a second sealing part 32 and a plurality of connections part 33, wherein the first sealing part 31 is provided on the first side of the metal bipolar plate, and the second sealing part 32 is provided on the second side of the metal bipolar plate (or, the The first sealing portion 31 and the second sealing portion 32 are respectively disposed on both sides of the first electrode plate 1), wherein the connecting portion 33 passes through the corresponding penetration hole 120, wherein the The first sealing part 31 , the second sealing part 32 and the connecting part 33 are integrally formed. In other words, the connecting portion 33 is penetrated through the corresponding through hole 120 and connects the first sealing portion 31 and the second sealing portion 32 into one body. As shown in FIG. 6 and FIG. 7 of the description, specifically, the first sealing part 31 of the sealing member 3 of the metal bipolar plate for a fuel cell of the present invention is provided on the first side of the metal bipolar plate 100. The second sealing portion 32 of the sealing member 3 is disposed on the second side 200 of the metal bipolar plate. It can be understood that the number of the connecting portions 33 is the same as the number of the penetration holes 120 .

Specifically, FIG. 5 of the accompanying drawings of the present specification shows the second side 200 of the metal bipolar plate, and the second sealing portion 32 of the sealing member 3 is shown in the figure. The second sealing part 32 of the sealing member 3 of the metal bipolar plate for a fuel cell of the present invention includes a flow field sealing part 321, wherein the flow field sealing part 321 is arranged to surround the second sealing part of the metal bipolar plate The entire flow field of the side 200 (including the reaction flow field, gas and cooling liquid inlets and outlets) is used for wrapping the entire flow field on the second side 200 of the metal bipolar plate.

Further, FIG. 6 and FIG. 7 respectively show cross-sections of two different embodiments of the sealing member 3 , and the cross-sections of the second sealing portion 32 of the sealing member 3 shown in the two figures are specifically the A cross section of the flow field sealing portion 321 of the second sealing portion 32 . As shown in FIG. 6 , in this embodiment, the flow field sealing portion 321 of the second sealing portion 32 is provided on the edge-enlarged portion 12 of the first polar plate 1 of the metal bipolar plate and the metal bipolar plate In the second polar plate 2 of the bipolar plate, in other words, a part of the flow field sealing part 321 of the second sealing part 32 is provided on the flared part 12 of the first polar plate 1 , and the other part is provided on the The second electrode plate 2 , wherein the flow field sealing portion 321 of the second sealing portion 32 extends from the expanding portion 12 of the first electrode plate 1 to the second electrode plate 2 . The advantage of this embodiment is that the size of the flared portion 12 of the first electrode plate 1 can be reduced, thereby reducing the size of the entire metal bipolar plate. However, in order to prevent the fluid sealant from being separated from the edge of the second polar plate 2 and the first Inflow between the pole plates 1 , the edge of the second pole plate 2 should be set to closely fit the first pole plate 1 . Preferably, the edge of the second pole plate 2 is completely welded or bonded to the first pole plate 1 . As shown in FIG. 7 , in this embodiment, the flow field sealing portion 321 of the second sealing portion 32 is only provided on the enlarged edge portion 12 of the first polar plate 1 of the metal bipolar plate, in other words, The flow field sealing portion 321 of the second sealing portion 32 is separated from the second electrode plate 2 . The advantage of this embodiment is that during the injection molding process of the sealing member 3 (the double-side glue injection process of the metal bipolar plate), the fluid sealant used to form the flow field sealing portion 321 does not escape from all Inflow between the edge of the second pole plate 2 and the first pole plate 1, the edge of the second pole plate 2 does not have to be completely welded or bonded to the first pole plate 1, and only needs to be directed against the described first pole plate 1. A specific area of the edge of the second pole plate 2 is welded or bonded. Of course, in this embodiment, the enlarged edge portion 12 of the first electrode plate 1 needs to provide enough space for the flow field sealing portion 321 of the second sealing portion 32 .

According to the above description of the metal bipolar plate used in the fuel cell of the present invention, and with reference to FIG. 8 , the injection molding method of the sealing member of the metal bipolar plate according to the embodiment of the present invention includes the following steps:

S1, prepare a first pole plate and a second pole plate, wherein the size of the first pole plate is larger than the size of the second pole plate, wherein the first pole plate includes a superimposed portion and an enlarged edge portion, wherein the The widening portion extends outward from the overlapping portion, wherein the size of the second pole plate is the same as the overlapping portion of the first pole plate, wherein the overlapping portion of the first pole plate forms a reaction side and a cooling side opposite to the reaction side of the overlapping portion, the second pole plate forms a reaction side and a cooling side opposite the reaction side of the second pole plate;

S2. The second pole plate is fixedly arranged on the overlapping portion of the first pole plate, wherein the cooling side of the second pole plate is facing the part of the overlapping portion of the first pole plate. the cooling side;

S3. Place the fixed first electrode plate and the second electrode plate in a mold, and inject fluid sealant to one side or both sides of the metal bipolar plate through the mold, wherein the fluid the encapsulant can flow from one side of the metal bipolar plate to the other side through the through holes of the metal bipolar plate; and

S4. After the fluid sealant is cured to form the seal, the mold is demolded.

In particular, before the step S3, the method further includes the step of: opening a plurality of the penetration holes in the enlarged edge portion of the first polar plate. It can be understood that the step of opening the penetrating hole is not affected by the second electrode plate, and can be performed simultaneously when the first electrode plate is prepared in the step S1, or after the step S2. , after the first pole plate and the second pole plate are fixed together, the penetration hole is opened in the enlarged edge portion of the first pole plate.

Specifically, the step S2 further includes the step of: welding or adhering the edge of the second electrode plate to the first electrode plate.

In an embodiment of the present invention, the step S2 includes the step of: welding or adhering the edge of the second electrode plate to the first electrode plate completely.

In another embodiment of the present invention, the step S2 includes the step of: partially welding or adhering the edge of the second pole plate to the first pole plate.

It should be understood by those of ordinary skill in the art that the above description and the embodiments shown in the accompanying drawings are only for exemplary explanation of the present invention, rather than limitation of the present invention. All equivalent implementations, modifications and improvements within the spirit of the present invention should be included within the protection scope of the present invention.

Claims (9)

1. A method of injection molding a seal member for a metallic bipolar plate for a fuel cell, comprising the steps of:

s1, preparing a first plate and a second plate, wherein the first plate has a size larger than that of the second plate, wherein the first plate includes a folded portion and a flared portion, wherein the flared portion extends outwardly from the folded portion, wherein the second plate has a size identical to that of the folded portion of the first plate, wherein the folded portion of the first plate forms a reaction side and a cooling side opposite to the reaction side of the folded portion, and the second plate forms a reaction side and a cooling side opposite to the reaction side of the second plate;

s2, fixedly arranging the second polar plate on the superposition part of the first polar plate, wherein the cooling side of the second polar plate is opposite to the cooling side of the superposition part of the first polar plate;

s3, placing the fixed first polar plate and the second polar plate in a mould, and injecting a fluid sealant to one side or two sides of the metal bipolar plate through the mould, wherein the fluid sealant can flow from one side to the other side of the metal bipolar plate through the penetrating holes of the metal bipolar plate;

S4, demolding after the fluid sealant is solidified to form the sealing element; and

before the step S3, the method further includes the steps of:

and a plurality of penetrating holes are formed in the edge expanding part of the first polar plate.

2. The injection molding method of a sealing member of a metallic bipolar plate according to claim 1, further comprising the step of, in the step S2:

and welding or bonding the edge of the second polar plate to the first polar plate.

3. A metallic bipolar plate for a fuel cell, comprising:

a first plate, wherein said first plate comprises a folded portion and a flared portion, wherein said flared portion extends outwardly from said folded portion, wherein said folded portion of said first plate forms a reaction side and a cooling side opposite said reaction side of said folded portion; and

a second plate, wherein said second plate defines a reaction side and a cooling side opposite to said reaction side of said second plate, wherein the size of said second plate is the same as the size of the stacked portion of said first plate, wherein said second plate is fixedly disposed at the stacked portion of said first plate, wherein said cooling side of said second plate is opposite to said cooling side of said stacked portion of said first plate, such that said second plate is stacked at said stacked portion of said first plate and said second plate and said flared portion of said first plate are offset from each other;

Wherein the metal bipolar plate has a plurality of through holes for the fluid sealant to flow through, wherein the through holes are all provided at the flared portion of the first electrode plate to prevent the through holes from being blocked by the second electrode plate.

4. The metallic bipolar plate for a fuel cell as recited in claim 3, further comprising a seal, wherein the seal comprises a first seal portion, a second seal portion and a plurality of connection portions, wherein the first seal portion is disposed on a first side of the metallic bipolar plate, the second seal portion is disposed on a second side of the metallic bipolar plate, the connection portions are disposed through the respective through holes, wherein the first seal portion, the second seal portion and the connection portions are integrally formed.

5. The metallic bipolar plate for a fuel cell as claimed in claim 4, wherein an edge of the second plate is integrally welded or bonded to the first plate.

6. The metallic bipolar plate for a fuel cell as claimed in claim 4, wherein an edge of the second plate is partially welded or bonded to the first plate.

7. The metallic bipolar plate for a fuel cell as claimed in claim 5, wherein the flow field seal of the second seal is provided at the flared portion of the first plate and the second plate, and the flow field seal extends from the flared portion of the first plate to the second plate.

8. The metallic bipolar plate for a fuel cell as set forth in claim 5 or 6, wherein the flow field seal of the second seal portion is provided only at the flared portion of the first plate, and the flow field seal portion is spaced apart from the second plate.

9. The metallic bipolar plate for a fuel cell as set forth in claim 5 or 6, wherein the sealing member is manufactured by an injection molding method of the sealing member of the metallic bipolar plate set forth in claim 1 or 2.

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