CN110797547A - Light self-temperature-equalizing bipolar plate based on foamed metal and preparation method thereof - Google Patents

Abstract

The invention discloses a light self-temperature-equalizing bipolar plate based on foamed metal and a preparation method thereof, wherein the bipolar plate structure comprises a plate body, a shell and foamed metal, the shell is arranged as an outer layer structure of the plate body, the foamed metal is arranged as an inner layer structure of the plate body, and a cavity of the foamed metal is filled with a phase-change material; the heat generated by the overheating area is stored through the phase-change material, and the heat transfer process is enhanced through the foam metal, so that the problems of small heat conductivity coefficient and long heat charging time of the phase-change material are solved; the heat stored in the phase change material can provide heat for the process of restarting the battery to reduce the corresponding time; the foamed metal material is used as a raw material for manufacturing the bipolar plate of the fuel cell, the shell is formed by laser sintering, and the difficulty of the manufacturing process of the bipolar plate is reduced by adopting the laser sintering technology.

Description

Light self-temperature-equalizing bipolar plate based on foamed metal and preparation method thereof

Technical Field

The invention relates to the field of electrochemical reaction devices, in particular to a light self-temperature-equalizing bipolar plate based on foam metal and a preparation method thereof.

Background

Energy shortage and environmental protection are two important problems restricting the development of the modern industrial society. The development and utilization of new energy and its technology are a major topic for promoting industrial transformation and upgrading, and environmental protection is reflected in clean utilization of energy in energy utilization. The electrochemical reaction device provides a new idea for solving the problem of clean utilization of energy. The electrochemical reaction device includes two types of energy supply devices represented by fuel cells and energy storage devices represented by flow batteries. The fuel cell is a device for directly converting chemical energy of fuel into electric energy, is not limited by Carnot cycle, and has the theoretical energy conversion rate as high as 100 percent. Since the fuel is not combusted, it does not generate harmful gas or dust, which is a pollutant difficult to control. The flow battery is a large-scale electricity storage and energy storage device capable of performing charging and discharging operations, and can reversibly convert chemical energy into electric energy.

The fuel cell and the flow battery are similar in structure, oxidation-reduction reaction essentially occurs in the cell, and the structure of the fuel cell and the flow battery mainly comprises a membrane, a catalyst, a diffusion layer, a bipolar plate and other key structures, and a current collecting plate, an end plate and other components. The bipolar plate mainly plays roles of supporting, distributing fluid, collecting current and the like and is a core component in the electrochemical reaction device. The uneven distribution of reactants and catalyst results in a difference in the progress of the reaction from place to place on the bipolar plate, thereby resulting in an uneven temperature distribution across the bipolar plate. The higher concentration of catalyst or reactant, the faster reaction, the more heat given off, which causes local overheating. The performance of fuel cells and flow batteries is greatly affected by the problems of uneven temperature distribution and heat management on the bipolar plates, and therefore the heat management problem is widely researched. Since the electrochemical reactions that occur are affected by temperature, the non-uniformity of the bipolar plate temperature distribution further exacerbates the degradation of fuel cell performance.

The electrochemical reaction in the electrochemical reaction device generates electric energy and heat energy at the same time, the electric energy outputs work, and the heat energy is dissipated outwards and cannot be effectively utilized. On the one hand, the accumulated heat on the bipolar plate can cause the temperature of the battery to rise, and loads are brought to the thermal management module; on the other hand, direct discharge of heat to the environment without utilization causes problems of thermal pollution and energy waste.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a light self-temperature-equalizing bipolar plate based on foam metal and a preparation method thereof, and solve the problem of local overheating of an electrochemical reaction device.

In order to achieve the purpose, the invention adopts the technical scheme that:

a light self-temperature-equalizing bipolar plate based on foamed metal comprises a plate body, a shell and the foamed metal; the shell is of an outer layer structure of the plate body, the foam metal is of an inner layer structure of the plate body, the shell and the foam metal are connected in an integrated mode, a phase-change material is filled in a cavity of the foam metal, the shell protrudes upwards to form a hollow rib plate, a downward-recessed flow channel is formed between the two rib plates, and the flow channel and the rib plate are arranged on the plate body at intervals.

Further, the shell is formed by laser sintering of a foam metal surface.

Further, the shell and the foam metal are made of copper, aluminum or alloy materials with high thermal conductivity.

Furthermore, the porosity of the foam metal is 0.50-0.95, and the pore diameter of the pores is 0.5-1 mm.

Furthermore, the melting point of the phase-change material filled in the cavity of the foam metal is 50-80 ℃.

Further, the phase change material is paraffin.

Further, the height and the width of the flow channel are equal.

Further, the width and the depth of the flow channel and the rib plate are equal.

A preparation method of the bipolar plate comprises the following steps:

(1) cutting a foam metal raw material into required size, and then processing a flow channel on the surface of the cut foam metal;

(2) soaking the machined foam metal in a liquid phase-change material stock solution to fully fill the phase-change material in pores of the foam metal, and cooling until the phase-change material in the foam metal does not flow any more;

(3) sealing the outer surface of the foam metal by adopting a laser sintering mode to form a shell;

(4) and grinding the surface of the manufactured bipolar plate to a designed size.

The invention has the following technical effects:

1. aiming at the problems of uneven temperature distribution and local overheating in the fuel cell, the phase-change material is filled in the bipolar plate, and the temperature of the bipolar plate is controlled in a reasonable range and is uniform by selecting the phase-change material with proper physical properties to absorb and store the heat of an overheating area; the problem of local overheating caused by uneven distribution of reactant concentration of the fuel cell is effectively solved, heat generated by an overheating area is stored through the phase-change material, the heat transfer process is strengthened through the foam metal, the problems of small heat conductivity coefficient and long heat charging time of the phase-change material are solved, and the heat stored in the phase-change material can provide heat for the process of restarting the cell so as to reduce the corresponding time.

2. Aiming at the problems of heaviness and large material consumption of the fuel cell bipolar plate, the invention adopts the foam metal material as the raw material for manufacturing the fuel cell bipolar plate, and simultaneously forms a shell through laser sintering to seal the surface of the foam metal, thereby avoiding the leakage of fuel/oxidant to the foam metal through a flow channel; the manufacturing process difficulty of the bipolar plate is reduced by adopting a laser sintering technology.

Drawings

FIG. 1 is a schematic view of a bipolar plate according to a preferred embodiment of the present invention;

FIG. 2 is a schematic view of a fuel cell incorporating the present invention;

in the figure: 1. a plate body; 2. a housing; 3. a metal foam; 4. a phase change material; 5. a rib plate; 6. a flow channel; 7. and a membrane electrode.

Detailed Description

The present invention will be described in further detail with reference to the following examples, which are not intended to limit the invention thereto.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.

As shown in figure 1, the light self-temperature-equalizing bipolar plate based on the foamed metal comprises a plate body 1, a shell 2, a foamed metal 3, a phase-change material 4, a rib plate 5 and a flow channel 6, wherein the shell 2 is an outer layer structure of the plate body 1, the foamed metal 3 is an inner layer structure of the plate body 1, the shell 2 is formed by laser sintering the surface of the foamed metal 3, the foamed metal 3 is made of copper, aluminum or an alloy material with high heat conductivity, the porosity of the foamed metal 3 is 0.50-0.95, and the pore diameter is 0.5-1 mm. The cavity of the foam metal 3 is filled with phase-change material 4 paraffin, and the selected paraffin has high phase-change latent heat, stable chemical property and melting point of 50-80 ℃.

The surface of the plate body 1 is sunken to form a flow channel 6, the surface of the plate body 1 is protruded to form a ribbed plate 5, the depth and the width of the flow channel 6 and the ribbed plate 5 are the same, the flow channel 6 and the ribbed plate 5 are arranged on the plate body 1 at intervals, and the height and the width of the flow channel 6 are equal.

The bipolar plate is manufactured by the following steps:

step 1, cutting a foam metal raw material into a size slightly larger than a final product in a mechanical cutting mode, and then processing a flow channel on the surface of the cut foam metal;

step 2, soaking the machined foam metal in a paraffin solution to fully fill paraffin in pores of the foam metal, and cooling until the paraffin in the foam metal does not flow any more;

and 3, sealing the outer surface of the foam metal one by adopting a laser sintering mode to form a shell with a certain thickness.

And 4, polishing the surface of the bipolar plate manufactured in the step 3 to be smooth to a designed size.

As shown in fig. 2, the fuel cell using the bipolar plate of the present invention operates as follows:

step S100: the fuel cell reactant respectively enters the anode and the cathode of the fuel cell through an external pipeline and is transferred to the membrane electrode direction through a flow channel on the bipolar plate;

step S200: the cathode and anode reactants respectively generate cell half-reactions on cathode and anode catalyst layers (positioned on membrane electrodes), and the reaction process is accompanied with the release of heat;

step S300: the heat generated on the membrane electrode is conducted outwards, and when the heat flows through the shell 2 with high heat conductivity coefficient, the heat is stored in the phase-change material 4 filled in the foam metal 3;

step S400: the foam metal 3 enhances the heat storage process in step S300 due to its high heat conductivity.

The fuel cell has a suitable working temperature, such as a high-efficiency working temperature range of 70-90 ℃ of the proton exchange membrane fuel cell. When the fuel cell goes through the process of working, stopping and restarting, the heat stored in the phase-change material is slowly released towards the membrane electrode, so that the fuel cell can be quickly started and reaches the rated working state.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (9)

1. A light self-temperature-equalizing bipolar plate based on foam metal is characterized in that: comprises a plate body (1), a shell (2) and a foam metal (3); the plate is characterized in that the shell (2) is of an outer layer structure of the plate body (1), the foam metal (3) is of an inner layer structure of the plate body (1), the shell (2) and the foam metal (3) are connected in an integrated mode, a phase change material (4) is filled in a cavity of the foam metal (3), the shell (2) protrudes upwards to form a hollow rib plate (5), a sunken flow channel (6) is formed between the two rib plates (5), and the flow channel (6) and the rib plate (5) are arranged on the plate body (1) at intervals.

2. A lightweight self-temperature-equalizing bipolar plate based on metal foam according to claim 1, wherein: the shell (2) is formed by laser sintering the surface of the foam metal (3).

3. A lightweight self-temperature-equalizing bipolar plate based on metal foam according to claim 2, wherein: the shell (2) and the foam metal (3) are made of copper, aluminum or alloy materials with high heat conductivity coefficients.

4. A lightweight self-temperature-equalizing bipolar plate based on metal foam according to claim 3, wherein: the porosity of the foam metal (3) is 0.50-0.95, and the pore diameter of the pores is 0.5-1 mm.

5. A lightweight self-temperature-equalizing bipolar plate based on metal foam according to claim 1, wherein: the melting point of the phase-change material (4) filled in the cavity of the foam metal (3) is 50-80 ℃.

6. A lightweight self-temperature-equalizing bipolar plate based on metal foam as in claim 5, wherein: the phase change material (4) is paraffin.

7. A lightweight self-temperature-equalizing bipolar plate based on metal foam according to any one of claims 1 to 6, characterized in that: the height and the width of the flow channel (6) are equal.

8. A lightweight self-temperature-equalizing bipolar plate based on metal foam according to claim 7, wherein: the width and the depth of the flow channel (6) and the rib plate (5) are equal.

9. A method of manufacturing a bipolar plate as claimed in any one of claims 1 to 8, comprising the steps of:

(1) cutting a foam metal raw material into required size, and then processing a flow channel on the surface of the cut foam metal;

(2) soaking the machined foam metal in a liquid phase-change material stock solution to fully fill the phase-change material in pores of the foam metal, and cooling until the phase-change material in the foam metal does not flow any more;

(3) sealing the outer surface of the foam metal by adopting a laser sintering mode to form a shell;

(4) and grinding the surface of the manufactured bipolar plate to a designed size.

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