A disc-shaped vein-like interdigitated proton exchange membrane fuel cell bipolar plate

Abstract

The present invention relates to a disc-shaped leaf vein-shaped interdigital proton exchange membrane fuel cell bipolar plate, comprising a bipolar plate body, an interdigital flow field is arranged on the bipolar plate body, the interdigital flow field is nearly circular, with the center point of the flow field as the center of the circle, the interdigital flow field includes a local flow field evenly divided into n equal parts, n≥2, the interdigital flow field includes a reaction gas inlet, a reaction gas outlet and a leaf vein-shaped gas flow channel, the leaf vein-shaped flow channel includes an inlet flow channel and an outlet flow channel, the reaction gas inlet is arranged at the outer end of the inlet flow channel, the reaction gas outlet is arranged at the outer end of the outlet flow channel, the reaction gas inlet and the reaction gas outlet are arranged alternately in a circumferential arrangement, the inlet flow channel and the outlet flow channel are alternately distributed on a circle, and the inlet flow channel and the outlet flow channel are discontinuous. By adopting the above technical solution, the reaction gas can be evenly distributed to all parts of the bipolar plate body, so that the reaction gas can be evenly distributed in the reaction flow field.

Description

Technical Field

[0001] The present invention relates to a bipolar plate for a proton exchange membrane fuel cell, and particularly to a bipolar plate for a proton exchange membrane fuel cell with a disk-shaped interdigitated flow field structure based on vein-like bionics. Background Art

[0002] Proton Exchange Membrane Fuel Cell (PEMFC) has an attractive market application prospect due to its high energy conversion efficiency, pollution-free, fast startup and other advantages. Compared with heat engines, the chemical energy of fuel cells is directly converted into electrical energy without preliminary conversion into heat energy. Therefore, the conversion is not limited by the Carnot cycle and can theoretically achieve a high efficiency of 90% conversion.

[0003] The core of a fuel cell is the membrane electrode and the bipolar plate. The membrane electrode is the place for electrochemical reactions; the bipolar plate provides gas distribution and current collection. To complete these two tasks of gas distribution and current collection, the bipolar plate is usually conductive, and its surface has two parts, convex and concave. The convex part (current collection ridge) is used to contact the electrode and collect current; the concave part (flow field) provides a channel for the gas to transfer to the electrode surface. This part of the bipolar plate with a concave-convex structure is called the flow field.

[0004] In fact, the power generation efficiency of a fuel cell depends to a large extent on the structure of the bipolar plate flow field. A high-quality flow field structure can improve the flow state of reactants and products, enable each part of the electrode to obtain reactants in a timely manner, and can timely remove cooling water, thereby improving the power generation efficiency of the fuel cell.

[0005] Common flow fields of bipolar plates for proton exchange membrane fuel cells include parallel flow fields, serpentine flow fields and interdigitated flow fields. A significant advantage of the parallel flow field is that the total pressure drop between the gas inlet and outlet is relatively low. However, when the width of the flow field is relatively large, the fluid distribution in each flow field will be uneven, which will cause the accumulation of water in some areas, resulting in an increase in transmission loss and thus reducing the current density.

[0006] The advantage of the serpentine flow field lies in its drainage ability, and a single flow path can promote the discharge of liquid water. However, in a large-area flow field, the pressure drop of the serpentine flow field is very large, and the gas concentration distribution is uneven.

[0007] The design of the interdigitated flow field promotes the forced convection of reaction gases in the diffusion layer, and its water management effect is far better than that of the parallel flow field and the serpentine flow field. However, the forced convection in the gas diffusion layer causes a large pressure drop loss. In the current prior art, due to the large pressure drop of the traditional interdigitated flow field, when the battery outputs power, the distribution of reactants is uneven, resulting in a reduction in the utilization rate of reactants and the motor, thereby affecting the stability of current output.

[0008] The vein-like structure is widely present in nature and is the product of long-term natural evolution. Therefore, it has many excellent properties in mass transfer and transportation. With the development of bionics, more and more researchers are applying it to scientific research. Summary of the invention

[0009] In summary, in order to overcome the deficiencies of the prior art, the present invention provides a disc-shaped leaf-veined interdigitated proton exchange membrane fuel cell bipolar plate with uniform reactant distribution and high electrode utilization.

[0010] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a disc-shaped leaf-veined interdigitated proton exchange membrane fuel cell bipolar plate, comprising a bipolar plate body, an interdigitated flow field is arranged on the bipolar plate body, the interdigitated flow field is nearly circular, with the center point of the flow field as the center of the circle, the interdigitated flow field includes a local flow field evenly divided into n equal parts, n≥2, the interdigitated flow field includes a reaction gas inlet, a reaction gas outlet and a leaf-veined gas flow channel, the leaf-veined flow channel includes an inlet flow channel and an outlet flow channel, the reaction gas inlet is arranged at the outer end of the inlet flow channel, the reaction gas outlet is arranged at the outer end of the outlet flow channel, the reaction gas inlet and the reaction gas outlet are arranged alternately in a circumferential manner, the inlet flow channel and the outlet flow channel are alternately distributed on a circle, and the inlet flow channel and the outlet flow channel are discontinuous.

[0011] By adopting the above technical solution, n reaction gas inlets are used to reduce the pressure drop, so that the reaction gas can be evenly distributed in the reaction flow field; by adopting leaf vein-shaped flow channels, the flow channels are diffusely distributed, and the reaction gas can be evenly distributed to all parts of the bipolar plate body.

[0012] The present invention is further arranged that: the inlet flow channel includes an inlet main flow channel and an inlet branch flow channel, the inlet branch flow channel is concentrically arranged on the inlet main flow channel, the inlet main flow channel is connected with the inlet branch flow channel, the outlet flow channel includes an outlet main flow channel and an outlet branch flow channel, the outlet branch flow channel is concentrically arranged on the outlet main flow channel, the outlet main flow channel is connected with the outlet branch flow channel, and the reaction gas inlet and the reaction gas outlet are both provided with sealing grooves.

[0013] By adopting the above technical solution, the circular structure is more conducive to the thermal management of the battery. The heat generated by the electrochemical reaction diffuses from the center of the circle to the surrounding area. The branch flow channels are concentrically arranged to make the current density more uniform, thereby improving the electrochemical performance of the overall fuel cell. The discontinuous flow channels force the gas to pass through the diffusion layer under pressure to participate in the reaction, thereby improving the gas utilization rate and battery power density, thereby improving the performance of the battery. A sealing groove is provided to prevent leakage of reaction gas during assembly.

[0014] The present invention is further configured such that: the intake air flow path includes three main intake air flow paths and a plurality of intake air branch flow paths, the exhaust air flow path includes three main exhaust air flow paths and a plurality of exhaust air branch flow paths, and the main reaction exhaust air flow paths communicate with each other.

[0015] By adopting the above technical solution, with multiple inlets, the flow path length is shortened, the pressure drop can be reduced, and with the multi-channel setting, the gas convection and diffusion capabilities within the effective area are enhanced through the pressure difference, thereby improving the performance of the battery.

[0016] The present invention is further configured such that: the width of each part of the flow path is equal.

[0017] By adopting the above technical solution, it is convenient for processing and the cost is reduced.

[0018] The present invention is further configured such that: the width of the flow path, the depth of the flow path and the width of the ridge are equal.

[0019] By adopting the above technical solution, the structure is simple and the stability is strong.

[0020] The present invention is further configured such that: the width of the flow path is 0.6 - 1 mm, the depth of the flow path is 0.6 - 1 mm, and the width of the ridge is 0.6 - 1 mm.

[0021] By adopting the above technical solution, the porosity of this flow field is about 50%, preventing the increase of Ohmic polarization loss of the battery due to too high porosity or the reduction of the utilization rate of reactants due to too low porosity.

[0022] The present invention is further configured such that: the planes where the deepest parts of the flow paths are located are the same plane.

[0023] By adopting the above technical solution, since the planes where the deepest parts of the flow paths are located are the same plane, it is easier to process and the cost is reduced.

[0024] The following describes the specific embodiments of the present invention in conjunction with the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic plan view of an embodiment of the present invention;

[0026] Figure 2 is a schematic three-dimensional view of an embodiment of the present invention;

[0027] Figure 3 is a schematic three-dimensional view of a partial flow field of an embodiment of the present invention;

[0028] Figure 4 is a comparison diagram of battery polarization curves of an embodiment of the present invention.

[0029] Reference numerals: 1. Bipolar plate body; 11. Interdigitated flow field; 111. Local flow field; 2. Reactant gas inlet; 3. Reactant gas outlet; 4. Vein-shaped gas flow channel; 41. Inlet gas flow channel; 411. Inlet main gas flow channel; 412. Inlet branch gas flow channel; 42. Outlet gas flow channel; 421. Outlet main gas flow channel; 422. Outlet branch gas flow channel; 5. Sealing groove. Detailed implementation mode

[0030] This specific embodiment is only an interpretation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

[0031] See the attached Figures 1-4 , a disk-shaped vein-shaped interdigitated proton exchange membrane fuel cell bipolar plate disclosed by the technical solution of the present invention, includes a bipolar plate body 1, and an interdigitated flow field 11 is arranged on the bipolar plate body 1. The interdigitated flow field 11 is nearly circular, with the center point of the flow field as the center of the circle. The interdigitated flow field 11 includes local flow fields 1 evenly divided into n equal parts, n≥2. The interdigitated flow field 11 includes a reactant gas inlet 2, a reactant gas outlet 3, and a vein-shaped gas flow channel 4. The vein-shaped flow channel includes an inlet gas flow channel 41 and an outlet gas flow channel 42. The reactant gas inlet 2 is arranged at the outer end of the inlet gas flow channel, and the reactant gas outlet 3 is arranged at the outer end of the outlet gas flow channel. The reactant gas inlet 2 and the reactant gas outlet 3 are arranged in an alternating manner in a circular arrangement. The inlet gas flow channel 41 and the outlet gas flow channel 42 are alternately distributed on a circle and the inlet gas flow channel 41 and the outlet gas flow channel 42 are not continuous.

[0032] The technical solution of the present invention is further provided: the inlet gas flow channel 41 includes an inlet main gas flow channel 411 and an inlet branch gas flow channel 412. The inlet branch gas flow channel 412 is concentrically arranged on the inlet main gas flow channel 411, and the inlet main gas flow channel 411 is communicated with the inlet branch gas flow channel 412. The outlet gas flow channel 42 includes an outlet main gas flow channel 421 and an outlet branch gas flow channel 422. The outlet branch gas flow channel 422 is concentrically arranged on the outlet main gas flow channel 421, and the outlet main gas flow channel 421 is communicated with the outlet branch gas flow channel 422. Sealing grooves 5 are arranged at both the reactant gas inlet 2 and the reactant gas outlet 3.

[0033] The technical solution of the present invention is further provided: the inlet gas flow channel 41 includes n inlet main gas flow channels 411 and multiple inlet branch gas flow channels 412. The outlet gas flow channel 42 includes n outlet main gas flow channels 421 and multiple outlet branch gas flow channels 422. The outlet main gas flow channels 421 of the reaction outlet communicate with each other.

[0034] In the technical solution of the present invention, a local flow field 1 includes an intake main flow channel 411, a plurality of intake branch flow channels 412, an exhaust main flow channel 421, and a plurality of exhaust branch flow channels 422.

[0035] In the technical solution of the present invention, it is further set that: the width of the intake main flow channel 411 is equal to the width of the exhaust main flow channel 421.

[0036] In the technical solution of the present invention, it is further set that: the width of the intake branch flow channel 412 is equal to the width of the intake main flow channel 411. The width of the exhaust branch flow channel 422 is equal to the width of the exhaust main flow channel 421.

[0037] In the technical solution of the present invention, it is further set that: a plurality of intake branch flow channels 412 and a plurality of exhaust branch flow channels 422 are hierarchically distributed from the outer circle to the inner circle of the circle.

[0038] In the technical solution of the present invention, it is convenient for processing. Preferably, it is further set that: the widths of all parts of the flow channel are equal.

[0039] In the technical solution of the present invention, it is further set that: the width of the flow channel, the depth of the flow channel are equal to the width of the ridge.

[0040] In the technical solution of the present invention, it is further set that: the width of the flow channel is 0.6 - 1 mm, the depth of the flow channel is 0.6 - 1 mm, and the width of the ridge is 0.6 - 1 mm.

[0041] In the technical solution of the present invention, it is further set that: the planes where the deepest parts of the flow channels are located are the same plane.

[0042] In the technical solution of the present invention, it is further set that: during the use of this bipolar plate, the reaction gas enters the bipolar plate flow channel from the reaction gas inlet 2, and the reaction gas is evenly distributed to the intake branch flow channels 412 through the intake main flow channel 411, and is convectively distributed to the diffusion layer under the action of pressure, and further convects to the exhaust branch flow channels 422, then converges to the exhaust main flow channel 421, and finally is discharged from the reaction gas outlet 3.

[0043] In the technical solution of the present invention, it is further set that: the anodic reaction gas is hydrogen and the cathodic reaction gas is air or oxygen during the use of this bipolar plate.

[0044] In the technical solution of the present invention, it is further set that: the bipolar plate of the proton exchange membrane fuel cell shown can be made of graphite material or metal material.

[0045] The "vein - like flow field" described in this article refers to a structure that imitates the veins and adopts one inlet and multiple branch flow channels.

[0046] Attached drawings Figure 4 The experimental conditions of the comparative graph of the battery polarization curve are as shown in the following table.

[0047] Table 1 Operating parameters

[0048] Parameter Value Operating pressure (Pa) 101325 Operating temperature (K) 343 Anode mass flow rate (kg / s) <![CDATA[7×10 -6 > Anode humidity 100% Anode drainage pressure (Pa) 2500 Cathode mass flow rate (kg / s) <![CDATA[1.43×10 -5 ,6.59×10 -5 > Anode humidity 100%

[0049] Although the terms such as bipolar plate body 1, interdigitated flow field 11, local flow field 111, reactant gas inlet 2, reactant gas outlet 3, vein-shaped gas flow channel 4, inlet gas flow channel 41, inlet main gas flow channel 411, inlet branch gas flow channel 412, outlet gas flow channel 42, outlet main gas flow channel 421, outlet branch gas flow channel 422, and sealing groove 5 are used more frequently in this article, the possibility of using other terms is not excluded. These terms are only used to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A disc-shaped vein-like interdigital proton exchange membrane fuel cell bipolar plate, comprising a bipolar plate body, and an interdigital flow field is arranged on the bipolar plate body. Characterized in that: The interdigital flow field is nearly circular, with the center point of the flow field as the center of the circle. The interdigital flow field includes locally divided flow fields evenly divided into n equal parts, where n≥2. The interdigital flow field includes a reactant gas inlet, a reactant gas outlet, and vein-like gas flow channels. The vein-like gas flow channels include an inlet air flow channel and an outlet air flow channel. The reactant gas inlet is arranged at the outer end of the inlet air flow channel, and the reactant gas outlet is arranged at the outer end of the outlet air flow channel. The reactant gas inlet and the reactant gas outlet are arranged in a circumferential and alternating manner. The inlet air flow channels and the outlet air flow channels are alternately distributed on a circle and the inlet air flow channels and the outlet air flow channels are not continuous; the inlet air flow channel includes an inlet main flow channel and inlet branch flow channels, and the inlet branch flow channels are concentrically arranged on the inlet main flow channel, and the inlet main flow channel is connected to the inlet branch flow channels. The outlet air flow channel includes an outlet main flow channel and outlet branch flow channels, and the outlet branch flow channels are concentrically arranged on the outlet main flow channel, and the outlet main flow channel is connected to the outlet branch flow channels. Sealing grooves are arranged at both the reactant gas inlet and the reactant gas outlet; the widths of the flow channels at various places are equal.

2. A disc-shaped vein-like interdigital proton exchange membrane fuel cell bipolar plate according to claim 1. Characterized in that: The inlet air flow channel includes n inlet main flow channels and a plurality of inlet branch flow channels, the outlet air flow channel includes n outlet main flow channels and a plurality of outlet branch flow channels, and the reaction outlet main flow channels communicate with each other.

3. A disc-shaped vein-like interdigital proton exchange membrane fuel cell bipolar plate according to claim 1. Characterized in that: The width of the flow channel, the depth of the flow channel are equal to the width of the ridge.

4. A disc-shaped vein-like interdigital proton exchange membrane fuel cell bipolar plate according to claim 3. Characterized in that: The width of the flow channel is 0.6 - 1 mm, the depth of the flow channel is 0.6 - 1 mm, and the width of the ridge is 0.6 - 1 mm.

5. A disc-shaped vein-like interdigital proton exchange membrane fuel cell bipolar plate according to claim 1. Characterized in that: The planes where the deepest parts of the flow channels are located are the same plane.

Images