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CN-116404194-B - Monopolar plate, bipolar plate, electric pile and fuel cell

CN116404194BCN 116404194 BCN116404194 BCN 116404194BCN-116404194-B

Abstract

The invention discloses a monopole plate, a bipolar plate, a galvanic pile and a fuel cell, and belongs to the technical field of fuel cells. Compared with the prior art, the unipolar plate and the bipolar plate of the invention have the advantages that the non-uniform change design is carried out on the throttling section in the flow field, the overall parasitic consumption of the flow field can be obviously reduced, more resources can be distributed to the downstream area of the flow field with low concentration of reactant substances and large concentration of generated substances, the downstream area is matched with the dynamic change process in the operation process of the fuel cell, so that the performance of the downstream area of the flow field is obviously enhanced, the performance of the fuel cell is improved, meanwhile, the current density difference between the upstream and the downstream of the surface of the membrane electrode is reduced, the working state of the whole active area is more stable and balanced, and the service life of the fuel cell can be effectively prolonged. The fuel cell stack and the fuel cell can improve the performance of the fuel cell by applying the bipolar plate.

Inventors

  • WANG YING
  • LIU DONGAN
  • REN ZHIXING
  • HUANG HAO

Assignees

  • 中汽创智科技有限公司

Dates

Publication Date
20260512
Application Date
20230301

Claims (9)

  1. 1. The monopole plate (100) comprises a plurality of flow channels (1) which are arranged at intervals along a first direction, wherein the flow channels (1) comprise a plurality of throttling sections (12) which are sequentially arranged at intervals along the flow direction of fluid in the flow channels (1), the throttling sections (12) comprise a contraction section (121) and an expansion section (122) which are sequentially connected along the flow direction of the fluid in the flow channels (1), the longitudinal section area of the contraction section (121) is sequentially reduced along the flow direction of the fluid in the flow channels (1), the longitudinal section area of the expansion section (122) is sequentially increased along the flow direction of the fluid in the flow channels (1), and the longitudinal sections are perpendicular to the flow direction of the fluid in the flow channels (1); It is characterized in that the method comprises the steps of, In the same flow passage (1) or two adjacent flow passages (1), a plurality of throttling sections (12) are divided into a plurality of groups along the flow direction of fluid in the flow passage (1), and each group of throttling sections (12) comprises a plurality of throttling sections (12); the distance between two adjacent throttling sections (12) of a plurality of groups of throttling sections (12) is sequentially reduced along the flowing direction of fluid in the flow passage (1), and/or the minimum longitudinal section area of the throttling sections (12) is sequentially reduced, and/or the lengths of the throttling sections (12) are sequentially reduced; The flow channel (1) further comprises a plurality of flow sections (11), and the longitudinal cross-sectional area of the flow sections (11) is unchanged along the flow direction of the fluid in the flow channel (1); In the same flow channel (1), a plurality of circulation sections (11) and a plurality of throttling sections (12) are alternately connected in sequence along the flow direction of fluid in the flow channel (1).
  2. 2. The unipolar plate according to claim 1, characterized in that the throttling section (12) further includes a connecting section (123) connected between the contracting section (121) and the expanding section (122).
  3. 3. The unipolar plate according to claim 2, characterized in that the longitudinal cross-sectional area of the connecting section (123) is constant along the flow direction of the fluid in the flow channel (1).
  4. 4. Unipolar plate according to claim 2, characterized in that the lengths of the convergent sections (121) of the groups of the throttling sections (12) decrease in succession, and/or the lengths of the divergent sections (122) of the groups of the throttling sections (12) decrease in succession, and/or the lengths of the connecting sections (123) of the groups of the throttling sections (12) decrease in succession, along the flow direction of the fluid in the flow channel (1).
  5. 5. Unipolar plate according to claim 4, characterized in that the lengths of the convergent sections (121) of the same set of restriction sections (12) decrease or remain unchanged in succession along the flow direction of the fluid in the flow channel (1), and/or the lengths of the divergent sections (122) of the same set of restriction sections (12) decrease or remain unchanged in succession, and/or the lengths of the connecting sections (123) of the same set of restriction sections (12) decrease or remain unchanged in succession.
  6. 6. Unipolar plate according to claim 1, characterized in that the spacing between adjacent two of the throttling segments (12) of a same set of throttling segments (12) decreases or does not change in succession along the flow direction of the fluid in the flow channel (1), and/or, The smallest longitudinal cross-sectional areas of the restriction sections (12) of the same group of restriction sections (12) decrease or remain the same in succession along the flow direction of the fluid in the flow channel (1), and/or, The lengths of the throttling sections (12) of the same group of throttling sections (12) are sequentially reduced or unchanged along the flow direction of the fluid in the flow passage (1).
  7. 7.A bipolar plate comprising a unipolar plate according to any one of claims 1-6.
  8. 8. A stack comprising the bipolar plate of claim 7.
  9. 9. A fuel cell comprising the stack of claim 8.

Description

Monopolar plate, bipolar plate, electric pile and fuel cell Technical Field The invention relates to the technical field of fuel cells, in particular to a monopole plate, a bipolar plate, a galvanic pile and a fuel cell. Background The proton exchange membrane fuel cell (Proton Exchange Membrane Fuel Cell, PEMFC) is used as a high-energy conversion device for directly converting chemical energy into electric energy through electrochemical reaction of hydrogen and oxygen, and is not limited by Carnot cycle because of no combustion in the power generation process, so the proton exchange membrane fuel cell has the characteristics of high energy conversion rate, environmental friendliness and the like, and has become one of the most ideal new energy technologies accepted in the world today. Has wide application prospect and great potential, and is widely applied to the fields of portable equipment, traffic, fixed power generation and the like. The proton exchange membrane fuel cell is formed by connecting a plurality of groups of single cells in series, and each group of single cell core components comprises a membrane electrode and a bipolar plate. The Membrane Electrode Assembly (MEA) is formed by a membrane that conducts ions (mostly hydrogen ions), catalytic electrodes (anode and cathode) disposed on either side of the membrane, respectively, and Gas Diffusion Layers (GDLs) on either side of the catalytic electrodes, which together provide the working interface for the electrochemical reaction. The membrane electrode assemblies and bipolar plates (also called flow field plates or diaphragm plates) arranged on two sides together form a single cell unit (unitcell), and the bipolar plates are used for separating fuel gas (hydrogen gas) and oxidant and providing paths for the fuel gas and the oxidant to reach the surface of the membrane electrode in the proton exchange membrane fuel cell, and also have the functions of collecting and conducting current, carrying out electrochemical reaction heat exchange, providing structural support for the membrane electrode assemblies and the like. In the working process of the fuel cell, hydrogen enters a bipolar plate through a hydrogen inlet manifold, is distributed into a hydrogen flow field through the bipolar plate and is diffused into a gas diffusion layer, so that hydrogen ions reach the surface of an anode catalytic electrode, then hydrogen ions penetrate through a proton membrane to reach the surface of a cathode catalytic electrode, electrons penetrate through the bipolar plate to reach the cathode of an adjacent single cell, an oxidizing agent enters the bipolar plate through an air inlet manifold, is distributed into an air flow field through the bipolar plate, so that electrochemical reaction is carried out on the surface of the cathode catalytic electrode, and reaction products and unreacted working medium are collected through the flow field and discharged out of the bipolar plate and further discharged out of the fuel cell through an exhaust manifold. In order to optimize mass transfer and drainage property of a polar plate flow field, the existing flow channel is introduced with a throttling structure which comprises a shrinkage section and an expansion section, and a pressure difference is formed between two adjacent flow channels by utilizing the principle of a venturi tube, so that three-dimensional flow of the flow field is realized, and the ridge-groove effect is weakened. In the running process of the fuel cell, along with the occurrence of electrochemical reaction along the flow direction of fluid in a flow channel, the reactant is gradually consumed, the concentration is gradually reduced, and the generated substance water is gradually accumulated. Disclosure of Invention The invention aims to provide a single-pole plate, a bipolar plate, a galvanic pile and a fuel cell, which are matched with the dynamic change process in the operation process of the fuel cell, so that the performance of the fuel cell is improved. In order to achieve the above object, the following technical scheme is provided: In a first aspect, a unipolar plate is provided, the unipolar plate includes a plurality of flow channels arranged at intervals along a first direction, the flow channels include a plurality of throttling sections arranged at intervals in sequence along a flow direction of fluid in the flow channels, the throttling sections include a contraction section and an expansion section connected in sequence along the flow direction of fluid in the flow channels, a longitudinal section area of the contraction section is reduced in sequence along the flow direction of fluid in the flow channels, and a longitudinal section area of the expansion section is increased in sequence along the flow direction of fluid in the flow channels; In the same flow passage or two adjacent flow passages, a plurality of throttling sections are divided into a plurality of groups along the