A water-cooled hydrogen fuel cell bipolar plate and preparation method thereof

Abstract

The present invention relates to the technical field of hydrogen energy, and specifically discloses a water-cooled hydrogen fuel cell bipolar plate and a preparation method thereof. The water-cooled hydrogen fuel cell bipolar plate includes a frame and a core body embedded and integrated in the frame. The core body includes a gas diffusion tube row integrated in the frame and having gas diffusion channels arranged inside, and a water-cooled tube row installed in the gas diffusion tube row and having cooling water channels arranged therein. An inlet, a drain outlet, an air inlet and an air outlet are arranged on the frame. The inlet and the drain outlet are respectively communicated with the cooling water channels, and the air inlet and the air outlet are respectively communicated with the gas diffusion channels. The water-cooled tube row is made of a premix material one prepared from ceramics or graphite powder, and the gas diffusion tube row is made of a graphite material and has a porous structure with pores of 0.5-3 μm. A preparation method thereof is also disclosed. The present invention effectively solves problems such as mass transfer, heat transfer, electrical conduction and electrochemical corrosion of traditional bipolar plates, and reduces the manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen energy, and more specifically, to a water-cooled hydrogen fuel cell bipolar plate and a preparation method thereof. Background Art

[0002] In the fuel cell system in the field of hydrogen energy, problems such as the long service life of the hydrogen fuel cell system, high hydrogen efficiency, power density, and process large-scale manufacturing cost need to be solved. As a core component of the hydrogen fuel cell, the bipolar plate plays an important role in mass transfer, heat dissipation, and electrical conduction in the fuel cell system, and its performance directly determines the service life, hydrogen efficiency, power density, and process large-scale manufacturing cost of the hydrogen fuel cell system. Especially for high-power hydrogen fuel cells, the problem of efficient heat dissipation of waste heat must be solved, because high temperature will directly affect the hydrogen efficiency and life of the proton membrane; the electrochemical corrosion of the bipolar plate not only affects the service life of the bipolar plate, but its corrosion products will also oxidize and corrode the proton membrane.

[0003] Currently, the most effective technical solution for efficient waste heat dissipation is through water cooling. Most of the electrochemical corrosion of the bipolar plate adopts a technical route of using metal cooling water pipes such as stainless steel and then preparing a corrosion coating on its surface. This anti-corrosion technical solution has certain defects, because the surface anti-corrosion coating cannot fundamentally solve the electrochemical corrosion problem, such as the coating peeling off caused by weak coating adhesion. There are also those that directly construct gas diffusion channels and cooling water channels on the graphite bipolar electrode, but the manufacturing process is complex and the manufacturing cost is high. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a water-cooled hydrogen fuel cell bipolar plate and a preparation method thereof; effectively solve the problems of mass transfer, heat transfer, electrical conduction, and electrochemical corrosion of traditional bipolar plates, and greatly reduce the manufacturing cost;

[0005] The solution adopted by the present invention to solve the technical problem is:

[0006] A water-cooled hydrogen fuel cell bipolar plate,

[0007] including a frame and a core body embedded and integrated in the frame;

[0008] The core body includes a gas diffusion tube row integrated in the frame and having gas diffusion channels inside, and a water-cooled tube row integrated in the gas diffusion tube row and having cooling water channels;

[0009] An inlet, a drain, an inlet port, and an outlet port are provided on the frame; wherein the inlet and the drain are respectively communicated with the cooling water channels, and the inlet port and the outlet port are respectively communicated with the gas diffusion channels;

[0010] The water cooling tube row is made of premix one prepared from ceramics or graphite powder. The gas diffusion tube row is made of premix two and has a porous structure with pores of 0.5 - 3 μm.

[0011] In some possible embodiments,

[0012] The water cooling tube row includes a first plate installed in the gas diffusion tube row and a cooling water flow channel arranged in the first plate; both ends of the cooling water flow channel are respectively communicated with a water inlet and a water outlet.

[0013] In some possible embodiments,

[0014] The water inlet and the water outlet are arranged on the same side and are communicated with both ends of the cooling water flow channel; the cooling water flow channel includes multiple groups of parallel water channels and connecting flow channels for connecting adjacent two groups of water channels.

[0015] In some possible embodiments,

[0016] Multiple rows of connecting holes are arranged on the first plate. Each row of connecting holes is located between adjacent two groups of water channels, and each row of connecting holes includes multiple holes.

[0017] In some possible embodiments,

[0018] The gas diffusion tube row includes a gas tube row provided with a gas diffusion flow channel, and a frame embedded and integrated on the outer side of the gas diffusion flow channel; a branch pipe communicated with one end of the gas diffusion flow channel is formed between the frame and the gas tube row; an air inlet and an exhaust port connected to the other end of the gas diffusion flow channel are formed between the frame and the gas tube row; a water inlet and a water outlet adapted to the cooling water flow channel are arranged on the frame; one side of the water cooling tube row close to the water inlet and the water outlet extends into the frame, and the cooling water flow channel is communicated with the water inlet and the water outlet.

[0019] In some possible embodiments,

[0020] The gas tube row includes a lower layer plate and an upper layer plate which are arranged in a stacked manner and form an installation cavity therebetween, and installation columns located in the installation cavity and arranged in one-to-one correspondence with the connecting holes; both ends of the installation columns are respectively connected to the upper layer plate and the lower layer plate; the water cooling tube row is installed in the installation cavity; there are two groups of gas diffusion flow channels which are respectively arranged in the lower layer plate and the upper layer plate.

[0021] In some possible embodiments,

[0022] There are two groups of air inlets and one group of exhaust ports. The air inlets are arranged corresponding to the intake ports, and the air outlets are arranged corresponding to the exhaust ports; the air inlets and the exhaust ports are arranged on the same side, and the exhaust port is located between the two groups of air inlets;

[0023] The gas diffusion flow channel includes an intake pipe unit one communicating with one group of intake ports, an intake pipe unit two communicating with the other group of intake ports, and an outlet pipe unit with one end communicating with the exhaust port and located between the intake pipe unit one and the intake pipe unit two.

[0024] In some possible embodiments,

[0025] The intake pipe unit one, the intake pipe unit two, and the outlet pipe unit have the same structure and their cross-sections are all U-shaped structures, and their openings are arranged on the side close to the water cooling pipe row.

[0026] A preparation method of the water-cooled hydrogen fuel cell bipolar plate as described above specifically includes the following steps:

[0027] Step S1: Manufacturing of the water cooling pipe row wax mold body and the gas diffusion pipe row wax mold body;

[0028] Step S2: Using the premix prepared from ceramic or graphite powder to manufacture the water cooling pipe row green body according to the water cooling pipe row wax mold body;

[0029] Step S3: Using the second premix prepared from graphite powder to manufacture the frame green body;

[0030] Step S4: Assembling the water cooling pipe row green body, the frame green body and the gas diffusion pipe row wax mold body, and using the second graphite material premix to manufacture an integrated green body including the water cooling pipe row green body, the frame green body and the gas diffusion pipe green body;

[0031] Step S5: Dewaxing and high-temperature sintering the integrated green body to obtain the core body green body;

[0032] Step S6: Based on the core body green body, performing core body-frame processing in a casting mold to obtain a bipolar plate blank;

[0033] Step S7: Processing the bipolar plate blank to complete the processing.

[0034] In some possible embodiments, steps S2 - S5 specifically include the following steps:

[0035] Preparation of the first premix and the second premix;

[0036] Among them, the first premix includes graphite powder and carbon black powder; among them, the mass ratio of graphite powder to carbon black powder is 3:1 to 5:1; the mass ratio of the premix to water is 7:0.5 to 8:0.5, the diameter of the graphite powder is 0.1 μm to 10 μm, and the diameter of the carbon black powder is 0.1 μm to 1 μm;

[0037] The second premix includes graphite powder, carbon black powder and a pore-forming agent; wherein, the mass ratio of the graphite powder to the carbon black powder is 3:1 to 5:1, and the mass ratio of the carbon black, graphite powder and pore-forming agent is 10:1 to 15:1; the mass ratio of the premix to water is 7:0.5 to 8:0.5, the diameter of the graphite powder is 0.1 μm to 10 μm, and the diameter of the carbon black powder is 0.1 μm to 1 μm;

[0038] Manufacture of water-cooled tube row green bodies;

[0039] Assemble the water-cooled tube row green body, the frame green body and the gas diffusion tube dewaxed mold body, and use the second premix to manufacture an integrated green body including the water-cooled tube row green body, the frame green body and the gas diffusion tube green body; specifically:

[0040] Place the assembly formed by the water-cooled tube row green body, the frame green body and the gas diffusion channel wax mold body into a mold, fill the second premix material at the gap, vibrate and compact it, and pre-press and form it;

[0041] The pre-pressed formed body is subjected to isostatic pressing at room temperature under a pressure of 8 MPa - 15 MPa in a soft mold, demolded and shaped to obtain an integrated green body;

[0042] Dewax and sinter the integrated green body at high temperature to obtain a core green body; specifically:

[0043] In a heating furnace, heat the integrated green body to 300 °C - 350 °C at a heating rate of 5 °C / min - 10 °C / min for drying dehydration and dewaxing; after dewaxing, cooling water channels and gas diffusion channels are formed;

[0044] In a high-temperature sintering furnace, sinter at a high temperature for 2 - 3 hours at a temperature of 1500 °C - 1800 °C at a heating rate of 5 °C / min - 10 °C / min;

[0045] Process and shape the integrated green body after high-temperature sintering to obtain a core green body;

[0046] Based on the core green body, perform core body-frame processing in a casting mold to obtain a bipolar plate blank; specifically:

[0047] Install the core green body in a casting mold; inject molten metal into the casting mold, let the molten aluminum alloy fill all the gaps in the mold, inject the molten metal into the gaps in the mold and the pores of the core green body, and demold as the mold cools to obtain a bipolar plate blank.

[0048] Compared with the prior art, the beneficial effects of the present invention:

[0049] The present invention manufactures the water cooling tube row by using graphite or ceramics, and manufactures the gas diffusion tube row by using graphite; since both ceramics and graphite are inert to electrochemical corrosion, the problem of electrochemical corrosion of the bipolar plate is completely solved;

[0050] The gas diffusion tube row prepared by the present invention using graphite has a porous structure and good gas permeability, meeting the mass transfer design requirements of hydrogen and oxygen for high-power fuel cells; at the same time, graphite has good electrical conductivity, meeting the electrical conductivity design requirements of high-power fuel cells;

[0051] In the present invention, the wax body is manufactured by the pressure casting method, the core body is manufactured by the lost wax method, and after the core body is manufactured, the frame and the core body are formed by the die casting method. The pressure casting method, the lost wax method, and the die casting method are technically mature, and can effectively achieve mass production and reduce production and processing costs. Brief Description of the Drawings

[0052] Figure 1 It is a schematic structural diagram of the water-cooled hydrogen fuel cell bipolar plate of the present invention;

[0053] Figure 2 It is a three-dimensional structural diagram of the frame of the present invention;

[0054] Figure 3 It is a sectional view of the water-cooled hydrogen fuel cell bipolar plate of the present invention;

[0055] Figure 4 It is a schematic structural diagram of the core body of the present invention;

[0056] Figure 5 It is a sectional view of the core body of the present invention;

[0057] Figure 6 It is a schematic connection diagram of the frame, the gas tube row, and the water cooling tube row of the present invention;

[0058] Figure 7 is Figure 6 an enlarged view of part A in;

[0059] Figure 8 It is a three-dimensional structure diagram of the water cooling tube row of the present invention;

[0060] Figure 9 It is a sectional view of the water cooling tube row of the present invention;

[0061] Figure 10 It is a schematic structural diagram of the frame and the gas tube row of the present invention;

[0062] Figure 11 is Figure 10 a sectional view of;

[0063] Figure 12 is Figure 10 a side view of;

[0064] Wherein: 1 - frame, 11 - water inlet, 12 - drain outlet, 13 - air inlet, 14 - air outlet, 1222 - annular groove, 2 - core body, 21 - water cooling tube bank, 211 - cooling water flow channel; 2111 - water channel, 2112 - connecting flow channel, 212 - hole, 22 - gas diffusion tube bank, 221 - gas tube bank, 2211 - gas diffusion flow channel, 22111 - gas pipe, 2212 - upper plate, 2213 - lower plate, 222 - frame, 2221 - branch pipe, 2222 - air inlet, 2223 - exhaust port, 2224 - water inlet, 2225 - water outlet. Detailed implementation mode

[0065] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. The "first", "second" and similar words mentioned in this application do not represent any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not represent a quantity limit, but mean that there is at least one. In the implementation of this application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In the description of the embodiments of this application, unless otherwise stated, the meaning of "multiple" refers to two or more. For example, multiple positioning posts refer to two or more positioning posts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] The present invention will be described in detail below.

[0067] As Figures 1 - 12 shown,

[0068] A water-cooled hydrogen fuel cell bipolar plate

[0069] comprises a frame 1 and a core body 2 embedded and installed in the frame 1;

[0070] The core body 2 includes a gas diffusion tube bank 22 installed in the frame 1 and internally provided with a gas diffusion flow channel 2211, and a water cooling tube bank 21 installed in the gas diffusion tube bank 22 and provided with a cooling water flow channel 211; the water cooling tube bank 21 and the gas diffusion tube bank 22 are integrally formed;

[0071] An inlet 11, a drain 12, an air inlet 13 and an air outlet 14 are provided on the frame 1; wherein the inlet 11 and the drain 12 are respectively communicated with the cooling water flow channel 211, and the air inlet 13 and the air outlet 14 are respectively communicated with the gas diffusion flow channel 2211;

[0072] The water cooling tube row 21 is made of a premix one prepared from ceramics or graphite powder, and the gas diffusion tube row 22 is made of graphite material and has a porous structure, and its pores are 0.5-3 μm.

[0073] Preferably, the cross-section of the gas diffusion flow channel 2211 is in a rectangular structure, with a length between 0.5 mm and 1 mm and a width between 0.2 mm and 0.5 mm. The cross-section of the cooling water flow channel 211 is in a rectangular structure, with a length between 1 mm and 2 mm and a width between 0.5 mm and 1 mm.

[0074] The gas diffusion tube row 22 made of graphite has good gas permeability and meets the mass transfer design requirements of high-power fuel cells for hydrogen and oxygen; at the same time, graphite has good electrical conductivity and meets the electrical conductivity design requirements of high-power fuel cells;

[0075] When the water cooling tube row 21 is prepared from ceramic materials, it has good thermal conductivity and solves the problem of waste heat discharge of high-power hydrogen fuel cell systems;

[0076] The present invention uses graphite and ceramics to manufacture the core body. Since both ceramics and graphite are inert to electrochemical corrosion, the problem of electrochemical corrosion of bipolar plates in the prior art is completely solved; during use, no corrosion products that have a great impact on the life of the membrane electrode are generated, reducing the impact of corrosion products on the proton membrane of the fuel cell, and the bipolar plate of the hydrogen fuel cell has a long life.

[0077] In the present invention, graphite material is used to prepare the gas diffusion tube row 22, which has a porous structure inside and good permeability, meeting the requirements of high-power fuel cells for efficient mass transfer of hydrogen and oxygen;

[0078] In some possible implementation manners,

[0079] Such as Figure 6 、 Figure 8 、 Figure 9 As shown, the water cooling tube row 21 includes a first plate installed in the gas diffusion tube row 22 and a cooling water flow channel 211 provided in the first plate; both ends of the cooling water flow channel 211 are respectively communicated with the inlet 11 and the drain 12.

[0080] In some possible implementation manners,

[0081] Such as Figure 2 As shown, the inlet 11 and the drain 12 are arranged on the same side and are communicated with both ends of the cooling water flow channel 211;

[0082] As Figure 9 shown, the cooling water flow channel 211 includes multiple groups of water channels 2111 arranged in parallel and connecting channels 2112 for connecting adjacent two groups of water channels.

[0083] As Figure 5 、 Figure 9 shown, multiple groups of water channels 2111 are arranged in parallel and are connected in series through the connecting channels 2112 in sequence; the inlet of the first group of water channels 2111 is communicated with the water inlet 11, and the outlet of the last group of water channels 2111 is communicated with the drain outlet 12;

[0084] In some possible implementation manners,

[0085] As Figure 8 、 Figure 9 shown, multiple rows of connection holes are arranged on the first plate, each row of connection holes is located between adjacent two groups of water channels 2111, and each row of connection holes includes multiple holes 212.

[0086] In some possible implementation manners,

[0087] As Figure 10 、 Figure 11 shown, the gas diffusion tube row 22 includes a gas tube row 221 provided with a gas diffusion flow channel 2211 and a frame 222 sleeved outside the gas diffusion flow channel 2211 and embedded in the frame 1; a branch pipe 2221 communicated with one end of the gas diffusion flow channel 2211 is formed between the frame 222 and the gas tube row 221; an air inlet 2222 and an exhaust outlet 2223 connected to the other end of the gas diffusion flow channel 2211 are formed between the frame 222 and the gas tube row 221; a water inlet 2224 and a water outlet 2225 adapted to the cooling water flow channel 211 are arranged on the frame 222; one side of the water cooling tube row 21 close to the water inlet 2224 and the water outlet 2225 extends into the frame 222 and the cooling water flow channel 211 is communicated with the water inlet 2224 and the water outlet 2225.

[0088] The frame 222 and the gas tube row 221 are integrally formed, and connection holes for connecting with the frame are arranged on the frame 222.

[0089] As Figure 1 shown, an annular groove 15 for installing the frame 222 is arranged on the inner side of the frame 1; the frame 222 is embedded in the annular groove 15, and the cross section of the annular groove 15 is in a U-shaped structure, and the water inlet 11, the drain outlet 12, the air inlet 13, and the air outlet 14 are respectively communicated with the annular groove 15.

[0090] The frame 1 and the frame 222 are formed into a whole by riveting; the whole frame 222 is embedded in the annular groove 15.

[0091] The branch pipe 2221 is arranged in parallel with the water channel 2111 and is communicated with the air pipe 22111 arranged on the upper layer plate 2212 and the lower layer plate 2213; the air pipe 22111 is perpendicular to and communicated with the branch pipe 2221;

[0092] In some possible embodiments,

[0093] such as Figure 6 、 Figure 10 、 Figure 11 As shown, the gas pipe row 221 includes a lower layer plate 2213 and an upper layer plate 2212 which are arranged in a stacked manner and form an installation cavity therebetween, and installation columns located in the installation cavity and arranged in one-to-one correspondence with the connection holes; both ends of the installation columns are respectively connected to the upper layer plate 2212 and the lower layer plate 2213; the water cooling pipe row 21 is installed in the installation cavity. The gas diffusion flow channels 2211 are two groups and are symmetrically arranged on the upper layer plate 2212 and the lower layer plate 2213, and one end of each of them is respectively communicated with the branch pipe 2221. The sides of the lower layer plate 2213 and the upper layer plate 2212 away from each other are coplanar with the two outer sides of the frame 1.

[0094] The lower layer plate 2213, the water cooling pipe row 21, and the upper layer plate 2212 are sequentially stacked to form a three-layer structure. The upper layer plate 2212 and the lower layer plate 2213 are made of graphite material and have a porous structure, so that the gas diffusion flow channels 2211 are breathable; the water cooling pipe row 21 is arranged between the upper layer plate 2212 and the lower layer plate 2213, and the cooling water flow channels 211 are located between the two layers of gas diffusion flow channels 2211;

[0095] In some possible embodiments,

[0096] such as Figure 11 As shown, there are two groups of air inlets 2222 and one group of air outlets 2223. The air inlets 2222 are arranged corresponding to the air inlets 13, and the air outlets 14 are arranged corresponding to the air outlets 2223; the air inlets 2222 and the air outlets 2223 are arranged on the same side and the air outlet 2223 is located between the two groups of air inlets 2222;

[0097] The gas diffusion flow channels 2211 include an intake pipe unit one communicated with one of the two groups of air inlets 2222, an intake pipe unit two communicated with the other group of air inlets 2222, and an outlet pipe unit with one end communicated with the air outlet 2223 and located between the intake pipe unit one and the intake pipe unit two.

[0098] In some possible embodiments,

[0099] such as Figure 11As shown, the intake pipe unit 1, the intake pipe unit 2, and the outlet pipe unit have the same structure and their cross-sections are all U-shaped, with their openings on the side close to the water cooling tube row 21.

[0100] The intake pipe unit 1, the intake pipe unit 2, and the outlet pipe unit each include multiple groups of air pipes 22111 that are perpendicular to the branch pipe 2221 and one end of which is connected to the branch pipe 2221. The air pipes 22111 in the intake pipe unit 1 and the intake pipe unit 2 are respectively connected to the corresponding air inlets 2222, and the air pipes 22111 of the outlet pipe unit are connected to the exhaust port 2223;

[0101] During use, the gas enters the air pipes 22111 in the intake pipe unit 1 or the intake pipe unit 2 through the two groups of air inlets 2222 respectively, then enters the branch pipe 2221, and then enters the air pipes 22111 in the outlet pipe unit, and finally is discharged through the exhaust port 2223. The gas presents a U-shaped structure from entry to discharge.

[0102] A preparation method of the water-cooled hydrogen fuel cell bipolar plate as described above specifically includes the following steps:

[0103] Step S1: Use the die casting method to manufacture the water cooling tube row wax mold body and the gas diffusion tube row wax mold body;

[0104] According to the structure of the cooling water flow channel 211, use the die casting method to manufacture the water cooling tube row wax mold body;

[0105] According to the structure of the gas diffusion tube row 22, use the die casting method to manufacture the gas diffusion tube row wax mold body;

[0106] When manufacturing the water cooling tube row wax mold body and the gas diffusion tube row wax mold body, use the plunger pump extrusion method to extrude the paraffin mixed material into their respective molds respectively, and after demolding, obtain the water cooling tube row wax mold body and the gas diffusion flow channel wax mold body respectively;

[0107] The paraffin mixed material includes paraffin, and uses one or two of short fibers and edible flour as additives. The die casting method for manufacturing the wax mold body is technically mature and will not be further elaborated here.

[0108] Step S2: Use the premix 1 prepared from ceramic or graphite powder, and manufacture the water cooling tube row green body according to the water cooling tube row wax mold body;

[0109] When using ceramic materials for the water cooling tube row green body, the premix 1 uses silicon nitride micropowder as the aggregate and Al2O3, CaO, and Fe2O3 as the binder to prepare the ceramic premix material; the content of silicon nitride micropowder in the ceramic slurry is 60%-80% (weight percentage), the total content of the binders Al2O3, CaO, and Fe2O3 is 20%-30%, and the water content of the material is 5%-10% (weight percentage);

[0110] When prepared with graphite powder, the first premix includes graphite powder and carbon black powder; wherein, the mass ratio of graphite powder to carbon black powder is 3:1 to 5:1; the mass ratio of the premix to water is 7:0.5 to 8:0.5, the diameter of the graphite powder is 0.1 μm to 10 μm, and the diameter of the carbon black powder is 0.1 μm to 1 μm;

[0111] Press and mold; place the manufactured water-cooling tube row wax mold body in the mold, fill the ceramic premix material in the gap, vibrate to compact, and pre-press and mold;

[0112] The pre-pressed body is formed in a soft film, and is subjected to isostatic pressing at room temperature with a pressure of 8 MPa - 15 MPa, demolded and shaped to obtain a water-cooling tube row blank body.

[0113] Step S3: Manufacture a frame blank body with the second premix prepared with graphite powder;

[0114] The second premix includes graphite powder, carbon black powder and a pore-forming agent; wherein, the mass ratio of graphite powder to carbon black powder is 3:1 to 5:1, and the mass ratio of carbon black, graphite powder and pore-forming agent is 10:1 to 15:1; the mass ratio of the premix to water is 7:0.5 to 8:0.5, the diameter of the graphite powder is 0.1 μm to 10 μm, and the diameter of the carbon black powder is 0.1 μm to 1 μm;

[0115] Further, the pore-forming agent is one or both of starch and methyl cellulose;

[0116] Step S4: Assemble the water-cooling tube row blank body, the frame blank body and the gas diffusion tube row wax mold body, and manufacture an integrated blank body including the water-cooling tube row blank body, the frame blank body and the gas diffusion tube blank body with the second premix;

[0117] Place the assembly formed by the water-cooling tube row blank body, the frame blank body and the gas diffusion channel wax mold body into the mold, fill the premix material in the gap between the water-cooling tube row blank body and the gas diffusion channel wax mold body, vibrate to compact, and pre-press and mold;

[0118] The holes 212 will be filled with the premix to connect the upper plate 2212 and the lower plate 2213 into a whole;

[0119] The pre-pressed body is subjected to isostatic pressing at room temperature with a pressure of 8 MPa - 15 MPa in a soft film, demolded and shaped to obtain an integrated blank body;

[0120] Step S5: Remove the wax from the integrated blank body and sinter it at high temperature to obtain a core blank body;

[0121] In a heating furnace, the integrated blank is heated to 300°C - 350°C at a heating rate of 5°C / min - 10°C / min for drying and dewaxing; after dewaxing, a cooling water flow channel 211 and a gas diffusion flow channel 2211 are formed;

[0122] In a high-temperature sintering furnace, at a heating rate of 5°C / min - 10°C / min, it is kept at a temperature of 1500°C - 1800°C for 2 - 3 hours for high-temperature sintering;

[0123] The integrated blank after high-temperature sintering is processed and shaped to obtain a core blank.

[0124] Preferably, the 3D printing technology can also be used to directly print the wax mold body of the gas diffusion flow channel on the outer side of the water-cooled pipe row blank of the integrated blank to obtain the integrated blank. After the two form an integral body, dewaxing and high-temperature sintering of the integrated blank are carried out to obtain the core blank. Dewaxing and high-temperature sintering of the integrated blank are carried out to obtain the core blank; the same as the above scheme will not be described here.

[0125] Step S6: Based on the core blank, the core blank-frame processing is carried out in a casting mold to prepare a bipolar plate blank;

[0126] Preferably, the frame 1 is a metal frame and can be prepared from aluminum alloy;

[0127] The core blank is installed in the casting mold; the molten aluminum alloy is injected into the casting mold to allow the molten aluminum alloy to fill all the gaps in the mold. The molten aluminum alloy is injected into the mold gaps and the pores of the core blank, and after cooling with the mold, demolding is carried out to obtain the bipolar plate blank.

[0128] On the blank with the core and the frame 1, the water inlet 11, the drain port 12, the air inlet 13, and the air outlet 14 are respectively machined, and the wire installation holes and the assembly holes are machined. Ensure that the water inlet 11 on the frame 1 communicates with the water inlet 2224, the drain port 12 with the water outlet 2225, the air inlet 13 with the air inlet 2222, and the air outlet 14 with the exhaust port 2223 and is sealed;

[0129] Step S7: The bipolar plate blank is processed to complete the processing.

[0130] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A water-cooled hydrogen fuel cell bipolar plate, characterized in that it includes a frame and a core embedded and integrated within the frame; the core includes a gas diffusion tube row integrated within the frame and having gas diffusion channels disposed therein, and a water-cooling tube row integrated within the gas diffusion tube row and having cooling water channels disposed therein; an inlet, a drain, an air inlet, and an air outlet are provided on the frame; wherein the inlet and the drain are respectively in communication with the cooling water channels, and the air inlet and the air outlet are respectively in communication with the gas diffusion channels; the water-cooling tube row is made of a premix one prepared from ceramic or graphite powder, and the gas diffusion tube row is made of a premix two prepared from graphite powder and has a porous structure with pores of 0.5 - 3 μm; the water-cooling tube row includes a first plate installed within the gas diffusion tube row and cooling water channels disposed within the first plate; both ends of the cooling water channels are respectively in communication with the inlet and the drain; the cooling water channels include multiple groups of water channels arranged in parallel and connecting channels for connecting adjacent two groups of water channels; multiple rows of connection holes are provided on the first plate, each row of connection holes is located between adjacent two groups of water channels, and each row of connection holes includes multiple holes; the gas diffusion tube row includes a gas tube row provided with gas diffusion channels and a border sleeved outside the gas diffusion channels and embedded and integrated within the frame; the gas tube row includes a lower plate and an upper plate arranged in a stacked manner and forming an installation cavity therebetween, and installation columns located within the installation cavity and arranged in one-to-one correspondence with the connection holes; both ends of the installation columns are respectively connected to the upper plate and the lower plate; the water-cooling tube row is installed within the installation cavity; the gas diffusion channels are two groups and are respectively arranged in the lower plate and the upper plate.

2. The water-cooled hydrogen fuel cell bipolar plate according to claim 1, characterized in that, The inlet and the drain are arranged on the same side and are in communication with both ends of the cooling water channels.

3. A water-cooled hydrogen fuel cell bipolar plate according to claim 1, characterized in that a branch pipe in communication with one end of the gas diffusion channel is formed between the border and the gas tube row; an air inlet and an exhaust port in connection with the other end of the gas diffusion channel are formed between the border and the gas tube row; a water inlet and a drain port adapted to the cooling water channels are provided on the border; one side of the water-cooling tube row close to the water inlet and the drain port extends into the border and the cooling water channels are in communication with the water inlet and the drain port.

4. A water-cooled hydrogen fuel cell bipolar plate according to claim 3, characterized in that: There are two groups of air inlets and one group of exhaust ports, the air inlets are arranged corresponding to the air inlet, and the air outlet is arranged corresponding to the exhaust port; the air inlets and the exhaust port are arranged on the same side and the exhaust port is located between the two groups of air inlets; the gas diffusion channels include an intake pipe unit one in communication with one group of air inlets, an intake pipe unit two in communication with the other group of air inlets, and an exhaust pipe unit having one end in communication with the exhaust port and located between the intake pipe unit one and the intake pipe unit two.

5. A water-cooled hydrogen fuel cell bipolar plate according to claim 4, characterized in that, The intake pipe unit one, the intake pipe unit two, and the exhaust pipe unit have the same structure and their cross-sections are all in a U-shaped structure with openings provided on the side close to the water-cooling tube row.

6. A preparation method of the water-cooled hydrogen fuel cell bipolar plate according to any one of claims 1-5, characterized in that, Specifically, it includes the following steps: Step S1: Manufacturing of the water-cooling tube row wax mold body and the gas diffusion tube row wax mold body; Step S2: The premix prepared with ceramic or graphite powder is used to manufacture the water-cooling tube row green body according to the water-cooling tube row wax mold body; Step S3: The premix prepared with graphite powder is used to manufacture the frame green body; Step S4: Assemble the water-cooling tube row green body, the frame green body and the gas diffusion tube row wax mold body, and use the second graphite material premix to manufacture an integrated green body including the water-cooling tube row green body, the frame green body and the gas diffusion tube green body; Step S5: Dewax and sinter the integrated green body at high temperature to obtain the core body green body; Step S6: Based on the core body green body, perform core body-frame processing in the casting mold to obtain the bipolar plate blank; Step S7: Process the bipolar plate blank to complete the processing.

7. The preparation method according to claim 6, characterized in that, Steps S2 to S6 specifically include the following steps: Preparation of the first premix and the second premix; Among them, the first premix includes graphite powder and carbon black powder; the mass ratio of graphite powder to carbon black powder is 3:1 to 5:1; the mass ratio of the premix to water is 7:0.5 to 8:0.5, the diameter of the graphite powder is 0.1 μm to 10 μm, and the diameter of the carbon black powder is 0.1 μm to 1 μm; The second premix includes graphite powder, carbon black powder and a pore-forming agent; the mass ratio of graphite powder to carbon black powder is 3:1 to 5:1, and the mass ratio of carbon black, graphite powder and pore-forming agent is 10:1 to 15:1; the mass ratio of the premix to water is 7:0.5 to 8:0.5, the diameter of the graphite powder is 0.1 μm to 10 μm, and the diameter of the carbon black powder is 0.1 μm to 1 μm; Manufacture of the water-cooling tube row green body; Assemble the water-cooling tube row green body, the frame green body and the gas diffusion tube row wax mold body, and use the second premix to manufacture an integrated green body including the water-cooling tube row green body, the frame green body and the gas diffusion tube green body; specifically: Place the assembly formed by the water-cooling tube row green body, the frame green body and the gas diffusion flow channel wax mold body into the mold, fill the second premix material in the gap, vibrate and compact it, and pre-press and form it; The pre-pressed formed body is subjected to isostatic pressing at room temperature with a pressure of 8 MPa - 15 MPa in the soft mold, demolded and shaped to obtain the integrated green body; Dewax and sinter the integrated green body at high temperature to obtain the core body green body; specifically: In the heating furnace, heat the integrated green body to 300 °C - 350 °C at a heating rate of 5 °C / min - 10 °C / min for drying and dehydration and dewaxing; after dewaxing, cooling water flow channels and gas diffusion flow channels are formed; In the high-temperature sintering furnace, at a heating rate of 5 °C / min - 10 °C / min, keep the temperature at 1500 °C - 1800 °C for 2 - 3 hours for high-temperature sintering; Process and shape the integrated green body after high-temperature sintering to obtain the core body green body; Based on the core body green body, perform core body-frame processing in the casting mold to obtain the bipolar plate blank; specifically: Install the core body green body in the casting mold; inject the molten metal into the casting mold, let the molten metal fill all the gaps in the mold, inject the molten metal into the gaps in the mold and the pores of the core body green body, and demold as the mold cools to obtain the bipolar plate blank.

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