CN114243045A

CN114243045A - Fuel cell unipolar plate and manufacturing method thereof

Info

Publication number: CN114243045A
Application number: CN202111348614.5A
Authority: CN
Inventors: 陈文淼; 朱晓春; 郗富强
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2022-03-25

Abstract

The invention relates to the technical field of fuel cells, and discloses a fuel cell unipolar plate and a manufacturing method thereof. This fuel cell unipolar board, including compression molding's graphite cake to and inlay and have the netted skeleton of heat conduction and/or electric conductivity ability in graphite cake inside, the first working face of graphite cake is provided with first recess, and the second working face of graphite cake is provided with the second recess. If the first groove is a reaction gas flow passage, the second groove is a cooling liquid flow passage; if the first groove is a cooling liquid flow channel, the second groove is a reaction gas flow channel. The unipolar plate of the fuel cell and the manufacturing method thereof provided by the invention can ensure that the unipolar plate and the bipolar plate manufactured by the unipolar plate have excellent corrosion resistance, low cost and excellent electric conduction, heat conduction and mechanical properties.

Description

Fuel cell unipolar plate and manufacturing method thereof

Technical Field

The invention relates to the technical field of fuel cells, in particular to a fuel cell unipolar plate and a manufacturing method thereof.

Background

The bipolar plate is one of the key components of the fuel cell, and mainly has the functions of supporting a flow field to transport reaction gas and cooling liquid, collecting and conducting current, heat and water generated by reaction, and has the requirements of good heat conduction and electric conduction capability, and excellent mechanical property and corrosion resistance.

The graphite bipolar plate is the first choice for batch application of fuel cells on commercial vehicles due to excellent corrosion resistance and lower cost. For example, fig. 1 shows a graphite bipolar plate, in which two unipolar plates 1, which are respectively molded by press molding, are joined up and down by a gluing process, and 101 is a reactant gas flow channel and 102 is a coolant flow channel.

However, the flexibility of the graphite raw material and the insulation of the resin filled in the pores lead to the difference of the electric conductivity, the heat conductivity and the mechanical properties of the graphite bipolar plate compared with the metal bipolar plate, and the popularization progress of the graphite bipolar plate is restricted to a certain extent.

Therefore, how to improve the electrical conductivity, thermal conductivity and mechanical properties of the bipolar plate while ensuring the bipolar plate to have excellent corrosion resistance and low cost is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present invention provides a monopolar plate for a fuel cell (which may be referred to as a monopolar plate for short), and a method for manufacturing the same, which can ensure that the monopolar plate and a bipolar plate manufactured by the same have excellent corrosion resistance, low cost, and excellent electrical conductivity, thermal conductivity, and mechanical properties.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a fuel cell unipolar board, includes compression molding's graphite cake, and inlays the inside netted skeleton that has heat conduction and/or electric conductivity ability of graphite cake, the first working face of graphite cake is provided with first recess, the second working face of graphite cake is provided with the second recess, wherein:

if the first groove is a reaction gas flow channel, the second groove is a cooling liquid flow channel;

and if the first groove is a cooling liquid flow channel, the second groove is a reaction gas flow channel.

Optionally, in the above fuel cell unipolar plate, the mesh skeleton comprises a mesh body and a first boss, wherein:

the plane of the reticular body is coplanar or parallel to the central plane of the graphite plate;

the first boss protrudes out of the plane of the reticular body and extends towards the first working surface.

Optionally, in the unipolar plate of the fuel cell, the mesh skeleton further includes a second boss protruding out of the plane of the mesh body and extending toward the second working surface.

Alternatively, in the above-described fuel cell unipolar plate, the mesh holes of the mesh body are a plurality of rectangular mesh holes arranged side by side.

Optionally, in the unipolar plate of the fuel cell, the mesh skeleton is made of red copper.

Optionally, in the fuel cell unipolar plate, a material of the mesh skeleton is a composite material having heat and/or electrical conductivity.

A fuel cell unipolar plate manufacturing method applied to the above fuel cell unipolar plate, the fuel cell unipolar plate manufacturing method comprising:

step S1: positioning and installing the reticular framework in a mould pressing cavity of a mould and between an upper mould and a lower mould of the mould;

step S2: filling an expanded graphite raw material for forming a graphite plate in the mould pressing cavity;

step S3: the upper die and the lower die are actuated to extrude the expanded graphite raw material to form the die-pressed unipolar plate.

Optionally, in the mold, the mesh framework is positioned by a clamp, and a rigid frame is arranged on the periphery of the mesh framework.

Optionally, in the method for manufacturing a unipolar plate of a fuel cell, the method further includes step S5: the upper side and the lower side of the molded unipolar plate are respectively provided with a first groove and a second groove in a compression molding manner, wherein if the first groove is a reaction gas flow passage, the second groove is a cooling liquid flow passage, and if the first groove is a cooling liquid flow passage, the second groove is a reaction gas flow passage.

Alternatively, in the above method for manufacturing a unipolar plate for a fuel cell, between step S2 and step S3, step S201 is further included: and vibrating the expanded graphite raw material uniformly.

According to the technical scheme, the fuel cell unipolar plate and the manufacturing method thereof provided by the invention are formed by compounding the net-shaped framework and the expanded graphite raw material, so that the mechanical strength of the unipolar plate in the length direction and the width direction can be improved by utilizing the material characteristics and the structural characteristics of the net-shaped framework distributed in a net shape, the bipolar plate formed by the unipolar plate and the bipolar plate formed by combining the unipolar plate can obtain excellent mechanical property, electric conduction property and heat conduction property, and the bipolar plate is favorable for integrating a larger area and a larger number of bipolar plates. Compared with the metal unipolar plate in the prior art, the fuel cell unipolar plate has excellent corrosion resistance and lower cost, and compared with the graphite unipolar plate in the prior art, the fuel cell unipolar plate has better electric conduction, heat conduction and mechanical properties.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural view of a prior art graphite bipolar plate;

fig. 2 is a schematic structural diagram of a mesh skeleton in a unipolar plate of a fuel cell provided by an embodiment of the present invention;

FIG. 3 is a schematic view of the installation structure of the mesh framework in the mold according to the embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of an expanded graphite material and a reticulated framework provided in accordance with an embodiment of the present invention, prior to being molded in a mold;

fig. 5 is a schematic cross-sectional view of the expanded graphite material and the mesh skeleton provided in the embodiment of the present invention when the molded unipolar plate is obtained by molding the expanded graphite material and the mesh skeleton in a mold;

fig. 6 is a schematic cross-sectional structure diagram of a molded unipolar plate according to an embodiment of the present invention;

fig. 7 is a schematic cross-sectional view of a molded unipolar plate with a rigid frame cut away according to an embodiment of the present invention;

fig. 8 is a schematic cross-sectional structure view of a molded unipolar plate product according to an embodiment of the present invention;

fig. 9 is a schematic cross-sectional view of a finished bonded bipolar plate provided in an embodiment of the present invention;

fig. 10 is a schematic flow chart of a method for manufacturing a bipolar plate of a fuel cell according to an embodiment of the present invention.

Detailed Description

The invention discloses a monopolar plate of a fuel cell (which can be called as a monopolar plate for short) and a manufacturing method thereof, which can ensure that the monopolar plate and a bipolar plate manufactured by the monopolar plate have excellent corrosion resistance, low cost and excellent electric conduction, heat conduction and mechanical properties.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 2 and 8, a fuel cell unipolar plate according to an embodiment of the present invention includes a graphite plate 3 formed by compression molding, and a mesh skeleton 2 embedded inside the graphite plate 3 and having heat and/or electrical conductivity, where a first working surface of the graphite plate 3 is provided with a first groove, and a second working surface of the graphite plate 3 is provided with a second groove. Wherein: if the first groove is a reaction gas channel 101, the second groove is a cooling liquid channel 102; if the first groove is the cooling liquid channel 102, the second groove is the reaction gas channel 101.

Therefore, the monopolar plate of the fuel cell is formed by compounding the reticular framework 2 and the expanded graphite raw material, so that the mechanical strength of the monopolar plate in the length direction and the width direction can be improved by utilizing the material characteristics and the structural characteristics of the reticular framework 2 which are distributed in a reticular manner, the bipolar plate formed by the monopolar plate and the monopolar plate which is combined with the monopolar plate can obtain excellent mechanical property, electric conduction property and heat conduction property, and the integration of a larger area and more bipolar plates is facilitated. Compared with the metal unipolar plate in the prior art, the fuel cell unipolar plate has excellent corrosion resistance and lower cost, and compared with the graphite unipolar plate in the prior art, the fuel cell unipolar plate has better electric conduction, heat conduction and mechanical properties.

In a preferred embodiment, the mesh skeleton 2 comprises a mesh body 201 and a first boss 203, wherein: the plane of the reticular body 201 is coplanar or parallel to the central plane of the graphite plate 3; the first projection 203 protrudes out of the plane of the mesh-like body 201 and extends toward the first working surface. Further, a second boss 204 is further disposed in the mesh framework 2, and the second boss 204 protrudes out of the plane where the mesh body 201 is located and extends toward the second working surface. Referring specifically to fig. 2, the first bosses 203 and the second bosses 204 extend vertically upward and downward along the height direction (or thickness direction) of the unipolar plate, respectively.

Therefore, the unipolar plate has excellent electric conduction, heat conduction and mechanical properties through the net-shaped body 201, and the transverse supporting strength of the unipolar plate is enhanced; the first bosses 203 and the second bosses 204 can strengthen the longitudinal supporting strength of the unipolar plate, shorten the electric conduction path and the heat conduction path of the unipolar plate, and improve the electric conduction performance and the heat conduction performance of the unipolar plate.

In specific implementation, the mesh holes of the mesh body 201 may be provided as a plurality of rectangular mesh holes arranged side by side, as shown in fig. 2. However, the mesh shape and the arrangement of the mesh body 201 may have various designs, for example, in other embodiments, the mesh shape may be configured as a parallelogram, or a hexagon, or a triangle, or a circle, or other shapes, and the arrangement may be adjusted according to actual needs, or may be designed differently according to the will of the skilled person.

Specifically, the mesh skeleton 2 may be made of red copper. That is, the mesh skeleton 2 is a mesh made of red copper. The wire mesh can be integrally formed through a hot pressing process, or can be obtained through any one or a plurality of other modes such as welding, splicing, fastener assembling and connecting and the like.

Alternatively, the material of the mesh-shaped framework 2 may also be a composite material with heat and/or electrical conductivity. That is, the mesh-like framework 2 is a mesh-like structure made of a composite material, the composite material has excellent heat conductivity, excellent electrical conductivity, or both excellent heat conductivity and excellent electrical conductivity, and the mesh-like structure of the composite material can be obtained by injection molding or hot pressing, or by any one or more of splicing, fastener assembly and connection or the like.

In a specific embodiment, only one layer of the mesh skeleton 2 may be disposed in the fuel cell unipolar plate, or two or more layers of the mesh skeleton 2 may be disposed in the fuel cell unipolar plate, and the number of the layers of the mesh skeleton 2 is not particularly limited in the present invention.

Referring to fig. 10, an embodiment of the present invention further provides a method for manufacturing a fuel cell unipolar plate suitable for the fuel cell unipolar plate. The method comprises the following steps:

step S1: positioning and installing the mesh framework 2 in a mould pressing cavity of a mould between an upper mould 401 and a lower mould 402 of the mould;

step S2: filling the mould pressing cavity with an expanded graphite raw material for forming a graphite plate 3;

step S3: the upper die 401 and the lower die 402 are operated to extrude the expanded graphite material to form the molded unipolar plate.

Specifically, referring to fig. 2 to 5, in the above mold, the mesh framework 2 may be positioned by a fixture, and correspondingly, a rigid frame 202 is disposed on the periphery of the mesh framework 2. Wherein, the net-shaped body 201 and the rigid frame 202 are fixedly connected by means of integral molding or mechanical connection.

Further, a positioning boss 205 is further disposed on the rigid frame 202 to facilitate positioning and mounting the mesh framework 2 in the mold. Therefore, the method for manufacturing a unipolar plate for a fuel cell further includes, after step S3, step S4: the rigid rim 202 is cut away.

Specifically, the method for manufacturing a unipolar plate for a fuel cell further includes, after step S3, step S5: and respectively compression-molding a first groove and a second groove on the upper side and the lower side of the molded unipolar plate, wherein if the first groove is a reaction gas channel 101, the second groove is a cooling liquid channel 102, and if the first groove is the cooling liquid channel 102, the second groove is the reaction gas channel 101.

Alternatively, in another specific embodiment, in step S3, the expanded graphite material may be extruded by the upper die 401 and the lower die 402 to form the molded unipolar plate, and the first concave grooves and the second concave grooves may be formed on the upper and lower side surfaces of the unipolar plate by the structures of the upper die 401 and the lower die 402.

Preferably, in the method for manufacturing a unipolar plate for a fuel cell, between step S2 and step S3, the method further includes step S201: vibrating the expanded graphite raw material uniformly. Thereby further ensuring that the powdery expanded graphite raw material can penetrate through the gaps of the reticular frameworks 2 for even filling.

Specifically, in the above mold, the upper mold 401 and the lower mold 402 are respectively an upper movable mold and a lower movable mold in the mold, and can simultaneously and equidistantly move in the height direction in the opposite direction, so as to simultaneously and equidistantly perform the action and the pressing to obtain the molded unipolar plate, thereby ensuring that the mesh-like framework 2 is centrally distributed in the graphite plate 3, and obtaining uniform performance.

Specifically, the upper mold 401 and the lower mold 402 are driven by a power mechanism such as a motor or a hydraulic pressure.

Specifically, referring to fig. 3 to 5, in the mold, the clamp is a hollow clamp, and includes an upper clamp unit 601 and a lower clamp unit 602. Wherein: the upper die 401 and the lower die 402 are respectively arranged in the support frame 7 in a way of moving up and down; the upper die 401 is positioned above the upper clamp unit 601, and a first elastic piece 501 is arranged in front of the upper clamp unit and the upper clamp unit; the lower mold 402 is positioned below the lower clamp unit 602, and a second elastic member 502 is arranged in front of the lower clamp unit and the lower clamp unit; when the upper die 401 moves downwards, the upper die slides downwards along the inner cavity of the upper clamp unit 601 and compresses the first elastic piece 501, and when the upper die is demolded, the action of the upper die 401 is opposite; when the lower mold 402 moves upward, it moves upward along the inner cavity of the lower clamp unit 602 and compresses the second elastic member 502, and when it is released, the action of the lower mold 402 is reversed.

It should be noted that the deep bosses (i.e. the first bosses 203 and the second bosses 204) of the mesh framework 2 have two forms after being molded, namely, vertical bosses 231 corresponding to the ridges and deformed bosses 232 corresponding to the grooves, as shown in fig. 8.

In addition, referring to fig. 9, when manufacturing the bipolar plate, the two bright cell electrode plates are connected up and down by the gluing process to form the fuel cell bipolar plate.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The utility model provides a fuel cell unipolar plate, its characterized in that, includes compression molding's graphite cake (3), and inlays the inside netted skeleton (2) that have heat conduction and/or electric conductivity ability of graphite cake (3), the first working face of graphite cake (3) is provided with first recess, the second working face of graphite cake (3) is provided with the second recess, wherein:

if the first groove is a reaction gas flow channel (101), the second groove is a cooling liquid flow channel (102);

if the first groove is a cooling liquid flow passage (102), the second groove is a reaction gas flow passage (101).

2. The fuel cell unipolar plate according to claim 1, wherein the mesh skeleton (2) includes a mesh body (201) and a first boss (203), wherein:

the plane of the reticular body (201) is coplanar or parallel to the central plane of the graphite plate (3);

the first boss (203) protrudes out of the plane of the reticular body (201) and extends towards the first working surface.

3. The fuel cell unipolar plate according to claim 2, wherein the mesh backbone (2) further comprises second bosses (204), the second bosses (204) protruding out of a plane of the mesh body (201) and extending toward the second working face.

4. The fuel cell unipolar plate according to claim 2, wherein the mesh of the mesh body (201) is a plurality of rectangular mesh arranged side by side.

5. The fuel cell unipolar plate according to any one of claims 1 to 4, characterized in that the material of the mesh skeleton (2) is red copper.

6. The fuel cell unipolar plate according to any one of claims 1 to 4, characterized in that the material of the mesh skeleton (2) is a composite material having heat and/or electrical conductivity properties.

7. A fuel cell unipolar plate manufacturing method applicable to the fuel cell unipolar plate according to any one of claims 1 to 6, characterized by comprising:

step S1: positioning and installing a mesh framework (2) in a mould pressing cavity of a mould between an upper mould (401) and a lower mould (402) of the mould;

step S2: filling the mould pressing cavity with expanded graphite raw materials for forming a graphite plate (3);

step S3: the upper die (401) and the lower die (402) are actuated to extrude the expanded graphite material to form a molded unipolar plate.

8. The method for manufacturing a fuel cell unipolar plate according to claim 7, wherein the mesh frame (2) is positioned by a jig in the mold, and a rigid frame (202) is provided on a peripheral side of the mesh frame (2).

9. The fuel cell unipolar plate manufacturing method according to claim 7, further comprising step S5: the upper side and the lower side of the molded unipolar plate are respectively provided with a first groove and a second groove in a compression molding manner, wherein if the first groove is a reaction gas flow passage (101), the second groove is a cooling liquid flow passage (102), and if the first groove is the cooling liquid flow passage (102), the second groove is the reaction gas flow passage (101).

10. The method for manufacturing a fuel cell unipolar plate according to claim 7, further comprising, between step S2 and step S3, step S201: and vibrating the expanded graphite raw material uniformly.