A battery bipolar plate, a battery stack and a fuel cell

Abstract

This invention provides a battery bipolar plate, a battery stack, and a fuel cell. The battery bipolar plate includes a gas-conducting region and a conductive region, which are not in contact. The battery stack includes a positive end plate, an anode insulating plate, an anode current collector, a battery bipolar plate, a non-uniform membrane electrode assembly, a battery bipolar plate, a cathode current collector, a cathode insulating plate, and a cathode end plate, which are sequentially stacked and fixed by a fastening device. In this invention, by structurally dividing the battery bipolar plate into gas-conducting and conductive regions, the power density of the battery stack is improved, and the heat dissipation function of the battery stack is effectively enhanced. This results in an 18% reduction in the voltage decay rate of the assembled fuel cell, i.e., an 18% improvement in durability, making it suitable for industrial-scale application.

Description

Technical Field

[0001] This invention belongs to the field of battery bipolar plate design technology, and relates to a battery bipolar plate, a battery stack, and a fuel cell. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a power generation device that directly converts the chemical energy of hydrogen-based fuels and oxygen into electrical energy. Its small size, light weight, mild operating conditions, high efficiency, low pollution, and low noise make it suitable as a portable energy source and power source for transportation. In recent years, countries around the world have been actively developing high-performance, long-lasting fuel cell stack modules for use in fuel cell vehicles.

[0003] As a highly promising power source for the future, hydrogen fuel cells need to meet the operational requirements of various application scenarios, with durability being a core concern. Due to the unique assembly methods and processes of fuel cells, once the stack is assembled, it is almost impossible to disassemble, repair, or replace components. Damage or corrosion in even one of hundreds of fuel cells can affect the output power and energy conversion efficiency of the entire stack. Therefore, improving the durability of hydrogen fuel cells plays a crucial role in the market application of fuel cells.

[0004] The durability mechanism of hydrogen fuel cells stems from two aspects: firstly, the aging of the catalyst in the membrane electrode assembly (MEA), and secondly, the corrosion of the bipolar plates. MEA aging is mainly manifested in changes in platinum loading and proton conductivity, while bipolar plate aging arises from long-term gas flow corrosion. Currently, bipolar plates are mainly classified into graphite bipolar plates and metal bipolar plates. Graphite bipolar plates have good electrical and thermal conductivity, especially high corrosion resistance and durability, but their disadvantages lie in their high processing difficulty, high cost, long production cycle, and large size. As fuel cell vehicles gradually become commercialized, the shortcomings of graphite bipolar plates will become increasingly apparent. The advantage of metal bipolar plates is their high gas barrier properties. In contrast, graphite itself has a porous structure, requiring specific processes to seal the pores during processing, and even then, it is difficult to guarantee the final gas barrier properties of graphite bipolar plates. Furthermore, metal bipolar plates are easier to process and can be made ultra-thin, resulting in a smaller volume compared to graphite bipolar plates, but their corrosion resistance is relatively poor. Therefore, there is an urgent need to design and develop a battery bipolar plate to improve the corrosion resistance of the metal bipolar plate, thereby improving the durability of the battery stack. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a battery bipolar plate, a battery stack, and a fuel cell. In this invention, by structurally dividing the battery bipolar plate into a gas flow zone and a conductive zone, the power density of the battery stack is improved, and the heat dissipation function of the battery stack is effectively enhanced. As a result, the voltage decay rate of the assembled fuel cell is reduced by 18%, that is, the durability is improved by 18%, making it suitable for industrial-scale application.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a battery bipolar plate, the battery bipolar plate comprising a gas guiding region and a conductive region, wherein the gas guiding region and the conductive region are not in contact.

[0008] In this invention, by dividing the bipolar plate of the battery into a gas flow zone and a conductive zone, the power density of the battery stack is improved, and the heat dissipation function of the battery stack is effectively enhanced. As a result, the voltage decay rate of the assembled fuel cell is reduced by 18%, that is, the durability is improved by 18%, making it suitable for industrial promotion and use.

[0009] It should be noted that in this invention, the bipolar plate serves as the main structural component of the battery stack, bearing all the pressing forces during stack assembly. The gas guiding area and the conductive area are designed not to contact each other. This structure ensures that the heat generated by the fuel cell can be better transferred out of the battery stack module via natural convection heat transfer through the internal ventilation, reducing the burden on the battery stack coolant. The bipolar plate design allows for a smaller coolant channel cross-sectional area, better ensuring plate strength. Furthermore, while improving fuel cell lifespan, the bipolar plate thickness is reduced. The composite material in the gas guiding area has a higher Poisson's ratio and elastic modulus, enabling it to withstand higher battery stack assembly forces. Using the same membrane electrode diffusion layer, the stack pressing force is the same, thus allowing for a reduction in the bipolar plate thickness and an increase in the battery stack power density.

[0010] Furthermore, the present invention does not impose special limitations on the size and shape of the gas guiding area, and those skilled in the art can make adaptive adjustments according to the actual situation, wherein the shape of the gas guiding area can be rectangular, square, etc.

[0011] As a preferred embodiment of the present invention, on the same plane of the battery bipolar plate, the gas guiding area is disposed at one end of the battery bipolar plate, and the conductive area is disposed at the other end of the battery bipolar plate.

[0012] It should be noted that on the same plane of the battery bipolar plate, the gas guiding area is located at one end of the battery bipolar plate, and the conductive area is located at the other end of the battery bipolar plate. They can be on the same plane of the battery bipolar plate, with the gas guiding area occupying a part of the plane and the conductive area occupying another part of the plane, and the two do not overlap.

[0013] It should be noted that the present invention employs a bipolar plate design with a gas flow guiding region and a conductive region for structural division. This avoids the long-term corrosion of the metal parts of the bipolar plate by charged current, which would affect its durability. Furthermore, by using an insulating gas flow guiding region, gas transmission and the strength of the bipolar plate can be guaranteed. The gas flow enters the diffusion layer through the insulating material channel, and electrons enter the anode side of the upper fuel cell layer through the external channel of the conductive region. The current path will not corrode the flow channel, effectively enhancing the corrosion resistance of the bipolar plate and thus improving the durability of the fuel cell.

[0014] Preferably, the gas guiding area is provided with a channel for airflow.

[0015] Preferably, a flow channel is provided around the outer periphery of the conductive region, the flow channel being used for the passage of electrons.

[0016] Preferably, the thickness of the gas guiding zone is 0.6 to 1.1 mm.

[0017] The reason why the thickness of the gas guiding region is limited to 0.6 to 1.1 mm in this invention is that within this range, the thickness of the gas guiding region and the conductive region have a layered range, which is more conducive to the performance of the battery bipolar plate.

[0018] As a preferred embodiment of the present invention, the gas guiding zone is made of an insulating material.

[0019] Preferably, the insulating material is any one of PPC, PPS, PVC, nylon, or composite resin material, and more preferably PPC.

[0020] The present invention specifies that the insulating material is further preferably PPC (referring to PPC plastic, specifically polypropylene carbonate), because PPC is the most suitable after comprehensively considering the application cost, manufacturing method and production process of the insulating material.

[0021] In a preferred embodiment of the present invention, the conductive region is made of a conductive and thermally conductive material.

[0022] It should be noted that the function of the conductive area in this invention is to provide a pathway for electrons generated at the cathode of the fuel cell to be transported to the anode side of the fuel cell in the next layer. The size and shape of the conductive area are not specifically limited, and those skilled in the art can make adaptive adjustments according to the actual situation. The shape of the conductive area can be rectangular, square, etc.

[0023] Preferably, the conductive and thermally conductive material is copper or beryllium copper, and more preferably copper.

[0024] It should be noted that copper is preferred as the conductive and thermally conductive material in this invention because it has good electrical and thermal conductivity, and its preparation process is mature and the cost is low.

[0025] Preferably, the surface of the conductive area is fully covered with an electroplated layer.

[0026] Preferably, the electroplated layer is made of nickel or gold.

[0027] It should be noted that the material for the electroplating layer in this invention is nickel or gold because nickel and gold plating can effectively improve the corrosion resistance of copper and greatly extend its lifespan, while not reducing the conductivity of the conductive area. The plating sequence is nickel plating first, followed by gold plating.

[0028] For example, the working principle of the battery bipolar plate provided by the present invention includes:

[0029] The bipolar plate of the fuel cell is functionally divided into two distinct regions: a gas conduction and diffusion region for gas transfer and diffusion, and a conductive region for electron transfer and chemical reaction. Since the electrochemical reaction in a fuel cell can cause corrosion of the bipolar plate surface by charged fluids, reducing its lifespan, the above design ensures that the electrochemical reaction region and charged particles do not contact the bipolar plate's conduction region, guaranteeing long-term high-efficiency operation and improving its durability. Hydrogen and air enter the bipolar plate from opposite sides of the fuel cell and diffuse uniformly into the membrane electrode assembly (MEA) under the influence of insulating material channels. Specifically, the turbulence design within the flow field achieves uniform fluid distribution.

[0030] In a second aspect, the present invention provides a battery stack comprising an anode end plate, an anode insulating plate, an anode current collector, a battery bipolar plate, a non-uniform membrane electrode, a battery bipolar plate, a cathode current collector, a cathode insulating plate, and a cathode end plate stacked sequentially and fixed by a fastening device, wherein the battery bipolar plate is the battery bipolar plate described in the first aspect.

[0031] It should be noted that the anode end plate, anode insulating plate, anode current collector, cathode current collector, cathode insulating plate, and cathode end plate in this invention are all known to those skilled in the art. This invention does not impose any special limitations on their structure. Those skilled in the art can make adaptive adjustments according to actual conditions. The materials used are also all known materials. For example, the anode end plate may be made of PPC or 6061 aluminum alloy, the anode insulating plate may be made of PPC / PPS, the anode current collector may be made of copper, and the surface of the anode current collector may be treated by first plating nickel and then gold. The cathode current collector may be made of copper, and the surface of the cathode current collector may be treated by first plating nickel and then gold. The cathode insulating plate may be made of PPC / PPS, and the cathode end plate may be made of PPC or 6061 aluminum alloy.

[0032] As a preferred embodiment of the present invention, the fastening device is a fastening bolt, which is respectively disposed at both ends of the battery stack for fixing.

[0033] It should be noted that the fastening device is specified as a fastening bolt in this invention because it can effectively improve the vibration and impact resistance of the battery stack. Its marking points can intuitively observe the height change of the battery stack, thus providing an early warning function for changes in the pressing force of the battery stack.

[0034] As a preferred embodiment of the present invention, the non-uniform film electrode is a modular electrode.

[0035] Preferably, the non-uniform film electrode includes a reaction region and a conductive region, wherein the conductive region is installed corresponding to the conductive region and the reaction region is installed corresponding to the gas guiding region.

[0036] It should be noted that the non-uniform membrane electrode in this invention also adopts a modular design, divided into a reaction region and a conductive region. The reaction region mainly involves the non-uniformity of the catalyst coating on the membrane electrode. Due to the conductive region design of the battery bipolar plate, electron transport exhibits a certain concentration, i.e., it is introduced from one side. If the existing membrane electrode design principle is adopted, it will increase the conductive pressure on the conductive region side, resulting in a high current density distribution at the interface, thereby reducing the durability of the membrane electrode. Therefore, a modular design was also adopted for the non-uniform membrane electrode.

[0037] It should be noted that the non-uniform membrane electrode in this invention mainly refers to the membrane electrode formed after the catalyst is non-uniform on the membrane electrode. This invention does not impose special limitations on the size and shape of the non-uniform membrane electrode, and those skilled in the art can make adaptive adjustments according to the actual situation. The shape of the non-uniform membrane electrode can be rectangular, square, etc.

[0038] Furthermore, non-uniform membrane electrode assemblies (MEAs) have different requirements for coating thickness in different regions. The area closer to the conductive region has a higher electrochemical reaction concentration and rate, making it more prone to platinum dissolution and carbon support corrosion. This also addresses the "edge effect" of gas distribution or temperature in existing technologies, avoiding large performance differences and uneven performance degradation rates in individual cells. Therefore, thickening the slurry at this point ensures consistent overall degradation of the MEA, guaranteeing both the durability of the non-uniform MEA and improving the overall consistency of the fuel cell.

[0039] Preferably, the thickness of the first conductive region is greater than the thickness of the reaction region.

[0040] It should be noted that the thickness of the first conductive region in this invention is greater than the thickness of the reaction region because this structure can fully protect the catalyst layer, thereby ensuring the lifespan of the non-uniform membrane electrode.

[0041] Preferably, the shape of the first conductive region is the same as the shape of the conductive region.

[0042] It should be noted that the shape of the first conductive region in this invention is the same as that of the conductive region, which is used to ensure unobstructed electronic transmission channels between fuel cells.

[0043] As a preferred embodiment of the present invention, the non-uniform film electrode is obtained in the following manner:

[0044] After homogenizing both sides of the membrane electrode, a catalyst is coated on both sides of the membrane electrode to obtain the homogenized membrane electrode. It should be noted that the catalyst in this invention can be a platinum catalyst, which is well known to those skilled in the art.

[0045] Preferably, the non-homogenization step includes: dividing both sides of the membrane electrode into five regions, and spraying the catalyst in the five regions using an ultrasonic method.

[0046] Preferably, the two sides of the membrane electrode are a cathode side and an anode side, and both the cathode side and the anode side include an air inlet side and an air outlet side.

[0047] In the five regions divided on the cathode side, the mass of the catalyst sprayed in the direction from the inlet side to the outlet side decreases sequentially; in the five regions divided on the anode side, the mass of the catalyst sprayed in the direction from the outlet side to the inlet side decreases sequentially.

[0048] As a preferred embodiment of the present invention, the material of the first conductive region is copper or beryllium copper, preferably copper.

[0049] Specifically, the aforementioned non-homogenization step can be as follows: within the five regions separated by the cathode side, the mass of the catalyst sprayed sequentially decreases from the inlet side to the outlet side, wherein the spraying is performed under vacuum adsorption conditions at 45°C, and the mass of the catalyst sprayed in the five regions along the direction from the inlet side to the outlet side is 0.22 mg / cm³. 2 0.21 mg / cm 2 0.2 mg / cm 2 0.19 mg / cm 2 0.18 mg / cm 2 ;

[0050] In the five regions divided on the anode side, the catalyst is sequentially sprayed from the outlet side to the inlet side. Spraying is performed under vacuum adsorption at 65°C. The mass of catalyst sprayed in each of the five regions along the outlet side to the inlet side is 1 mg / cm³. 2 0.9 mg / cm 2 0.8 mg / cm 2 0.7 mg / cm 2 0.6 mg / cm 2 .

[0051] Preferably, both the anode current collector and the cathode current collector are made of copper.

[0052] Preferably, the surfaces of both the anode current collector and the cathode current collector are fully covered with an electroplated layer.

[0053] Preferably, the electroplated layer is made of nickel or gold.

[0054] Preferably, both the anode and cathode end plates are made of composite resin material.

[0055] It should be noted that the composite resin material in this invention can be formed by compression molding or injection molding. Its main function is to bear pressure and connect. Therefore, it is understood that this invention does not impose any special limitations on the composite resin material, and those skilled in the art can make adaptive adjustments according to the actual situation.

[0056] The battery stack of this invention is simple to install, reduces process complexity, facilitates industrial mass production, and allows for easy series and parallel stacking of multiple battery stack modules. It also reduces manufacturing and maintenance costs. The battery stack design of this invention avoids the corrosive effect of the original fuel cell airflow on the bipolar plate channels. Calculations and evaluations show that durability is improved by 18% compared to the original design, while also enhancing the battery stack's impact and vibration resistance.

[0057] Thirdly, the present invention provides a fuel cell comprising the battery stack described in the second aspect.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] In this invention, by dividing the bipolar plate of the battery into a gas flow zone and a conductive zone, the power density of the battery stack is improved, and the heat dissipation function of the battery stack is effectively enhanced. As a result, the voltage decay rate of the assembled fuel cell is reduced by 18%, that is, the durability is improved by 18%, making it suitable for industrial promotion and use. Attached Figure Description

[0060] Figure 1 A schematic diagram of a non-uniform film electrode in a battery stack provided in a specific embodiment of the present invention;

[0061] Figure 2 A front view of a non-uniform film electrode in a battery stack provided in a specific embodiment of the present invention;

[0062] Figure 3 A side view of a non-uniform film electrode in a battery stack provided for a specific embodiment of the present invention;

[0063] Figure 4 A schematic diagram of the structure of a battery bipolar plate provided in a specific embodiment of the present invention;

[0064] Figure 5 A front view of a battery bipolar plate provided in a specific embodiment of the present invention;

[0065] Figure 6 A schematic diagram of the assembly of a fuel cell provided for a specific embodiment of the present invention;

[0066] Figure 7 A schematic diagram of a stacked fuel cell provided for a specific embodiment of the present invention;

[0067] Figure 8 A linear variation graph of the coating thickness of the catalyst and its distance from the conductive region, provided for a specific embodiment of the present invention;

[0068] Wherein, 1-conductive region one; 2-reaction region; 3-conductive region; 4-gas guiding region. Detailed Implementation

[0069] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0070] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0071] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving complete process, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0072] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0073] In one specific embodiment, the present invention provides a battery bipolar plate, such as... Figure 4 , Figure 5 As shown, the battery bipolar plate includes a gas guiding region 4 and a conductive region 3, and the gas guiding region 4 and the conductive region 3 are not in contact.

[0074] In this invention, by dividing the bipolar plate of the battery into a gas flow zone 4 and a conductive zone 3, the power density of the battery stack is improved, and the heat dissipation function of the battery stack is effectively enhanced. As a result, the voltage decay rate of the assembled fuel cell is reduced by 18%, that is, the durability is improved by 18%, making it suitable for industrial promotion and use.

[0075] It should be noted that in this invention, the bipolar plate serves as the main structural component of the battery stack, bearing all the pressing forces during stack assembly. The gas guiding region 4 and the conductive region 3 are designed not to contact each other. This structure ensures that the heat generated by the fuel cell can be better transferred out of the battery stack module via natural convection heat exchange through internal ventilation, reducing the burden on the battery stack coolant. The bipolar plate design allows for a smaller coolant channel cross-sectional area, better ensuring plate strength. Furthermore, while improving fuel cell lifespan, the bipolar plate thickness is also reduced. The composite material of the gas guiding region 4 has a higher Poisson's ratio and elastic modulus, enabling it to withstand higher battery stack assembly forces. Using the same membrane electrode diffusion layer, the stack pressing force is the same, thus allowing for a reduction in the bipolar plate thickness and an increase in the battery stack power density.

[0076] Furthermore, the present invention does not impose any special limitations on the size and shape of the gas guiding region 4. Those skilled in the art can make adaptive adjustments according to the actual situation. The shape of the gas guiding region 4 can be rectangular, square, etc.

[0077] On the same plane of the battery bipolar plate, the gas guiding region 4 is set at one end of the battery bipolar plate, and the conductive region 3 is set at the other end of the battery bipolar plate. The gas guiding region 4 is provided with a channel for airflow. The conductive region 3 is surrounded by a flow channel for electrons to pass through.

[0078] The thickness of the gas guiding zone is 0.6–1.1 mm.

[0079] It should be noted that the present invention employs a bipolar plate design with a gas flow guide region 4 and a conductive region 3 for structural division. This avoids the long-term corrosion of the metal parts of the bipolar plate by the electric current, which would affect its durability. Furthermore, by using an insulating material for the gas flow guide region 4, gas transmission and the strength of the bipolar plate can be guaranteed. The gas flow enters the diffusion layer through the insulating material channel, and electrons enter the anode side of the upper fuel cell layer through the outer channel of the conductive region 3. The current path will not corrode the flow channel, effectively enhancing the corrosion resistance of the bipolar plate and thus improving the durability of the fuel cell.

[0080] The gas guiding region 4 is made of a different material than the conductive region 3; the gas guiding region 4 is made of an insulating material.

[0081] The insulating material is any one of PPC, PPS, PVC, nylon or composite resin material, and more specifically PPC.

[0082] The conductive region 3 is made of a conductive and thermally conductive material. It should be noted that the function of the conductive region 3 in this invention is to provide a pathway for electrons generated at the cathode of the fuel cell to be transported to the anode side of the upper fuel cell. The size and shape of the conductive region 3 are not specifically limited, and those skilled in the art can make adaptive adjustments according to the actual situation. The shape of the conductive region 3 can be rectangular, square, etc.

[0083] Furthermore, the conductive and thermally conductive material is copper or beryllium copper, and even more specifically, copper. The surface of the conductive region 3 is fully covered with an electroplated layer, the material of which is nickel or gold.

[0084] For example, the working principle of the battery bipolar plate provided by the present invention includes:

[0085] The bipolar plate of the fuel cell is functionally divided into two distinct regions: the gas conduction region 4 facilitates gas conduction and diffusion, while the conductive region 3 transfers electrons to complete the chemical reaction. Since the electrochemical reaction in the fuel cell can cause current-carrying fluids to corrode the bipolar plate surface, reducing its lifespan, the above design ensures that the electrochemical reaction region 2 and charged particles do not contact the bipolar plate's conduction region, guaranteeing long-term high-efficiency operation and improving its durability. Hydrogen and air enter the bipolar plate from both sides of the fuel cell and diffuse uniformly into the membrane electrode assembly under the influence of insulating material channels. Specifically, the turbulence design within the flow field achieves uniform fluid distribution.

[0086] In another specific embodiment, the present invention provides a battery stack, such as Figure 1 , Figure 2 , Figure 3 As shown, the battery stack includes an anode end plate, an anode insulating plate, an anode current collector, a battery bipolar plate, a non-uniform membrane electrode, a battery bipolar plate, a cathode current collector, a cathode insulating plate, and a cathode end plate stacked in sequence and fixed by a fastening device. The battery bipolar plate is the battery bipolar plate described in a specific embodiment.

[0087] It should be noted that the anode end plate, anode insulating plate, anode current collector, cathode current collector, cathode insulating plate, and cathode end plate in this invention are all known to those skilled in the art. This invention does not impose any special limitations on their structure. Those skilled in the art can make adaptive adjustments according to actual conditions. The materials used are also all known materials. For example, the anode end plate may be made of PPC or 6061 aluminum alloy, the anode insulating plate may be made of PPC / PPS, the anode current collector may be made of copper, and the surface of the anode current collector may be treated by first plating nickel and then gold. The cathode current collector may be made of copper, and the surface of the cathode current collector may be treated by first plating nickel and then gold. The cathode insulating plate may be made of PPC / PPS, and the cathode end plate may be made of PPC or 6061 aluminum alloy.

[0088] The fastening device is a fastening bolt, which is respectively installed at both ends of the battery stack for fixation. It should be noted that the fastening device is limited to fastening bolts in this invention because it can effectively improve the vibration and impact resistance of the battery stack. The marking points can be used to visually observe changes in the height of the battery stack, thus providing an early warning function for changes in the pressing force of the battery stack.

[0089] The non-uniform membrane electrode is a modular electrode, comprising a reaction region 2 and a conductive region 1. Conductive region 1 is mounted corresponding to conductive region 3, and reaction region 2 is mounted corresponding to gas flow region 4. It should be noted that the non-uniform membrane electrode in this invention also adopts a modular design, divided into a reaction region 2 and a conductive region 1. The reaction region 2 mainly involves the non-uniformity of the catalyst coating on the membrane electrode. Due to the design of the conductive region 3 of the battery bipolar plate, electron transport exhibits a certain degree of concentration, i.e., it is introduced from one side. If existing membrane electrode design principles are adopted, the conductive pressure on the conductive region 1 side will increase, resulting in a high current density distribution at the interface, thereby reducing the durability of the membrane electrode. Therefore, a modular design was also adopted for the non-uniform membrane electrode.

[0090] It should be noted that the non-uniform membrane electrode in this invention mainly refers to the membrane electrode formed after the catalyst is non-uniform on the membrane electrode. This invention does not impose special limitations on the size and shape of the non-uniform membrane electrode, and those skilled in the art can make adaptive adjustments according to the actual situation. The shape of the non-uniform membrane electrode can be rectangular, square, etc.

[0091] Furthermore, non-uniform film electrodes have different requirements for the coating thickness in different regions of the film electrode, such as... Figure 8 As shown, the area close to the conductive region -1 has a higher electrochemical reaction concentration and a faster reaction rate, making it more prone to platinum dissolution and carbon support corrosion. This also solves the "edge effect" of gas distribution or temperature in existing technologies, avoiding the problems of large performance differences and uneven performance degradation rates in individual cells. Therefore, thickening the slurry at this point ensures consistent overall degradation of the membrane electrode assembly, guaranteeing both the durability of the non-uniform membrane electrode assembly and improving the overall consistency of the fuel cell.

[0092] The thickness of conductive region 1 is greater than the thickness of reaction region 2. It should be noted that the thickness of conductive region 1 is greater than the thickness of reaction region 2 in this invention because this structure can fully protect the catalyst layer, thereby ensuring the lifespan of the non-uniform membrane electrode.

[0093] The shape of conductive region 1 is the same as that of conductive region 3. It should be noted that the fact that conductive region 1 and conductive region 3 have the same shape in this invention is to ensure unobstructed electron transmission channels between fuel cells.

[0094] The non-uniform membrane electrode is obtained as follows: after non-uniformizing both sides of the membrane electrode, a catalyst is coated on both sides of the membrane electrode to obtain the non-uniform membrane electrode; it should be noted that the catalyst in this invention can be a platinum catalyst.

[0095] Preferably, the non-uniformity step includes: dividing both sides of the membrane electrode into five regions, and spraying the catalyst in the five regions using an ultrasonic method.

[0096] The membrane electrode has a cathode side and an anode side on both sides, and both the cathode side and the anode side include an inlet side and an outlet side.

[0097] In the five regions divided on the cathode side, the mass of the catalyst sprayed in the direction from the inlet side to the outlet side decreases sequentially; in the five regions divided on the anode side, the mass of the catalyst sprayed in the direction from the outlet side to the inlet side decreases sequentially.

[0098] Specifically, the aforementioned non-homogenization step can be as follows: in five regions separated by the cathode side, the mass of the catalyst sprayed sequentially decreases from the inlet side to the outlet side, wherein the spraying is performed under vacuum adsorption conditions at 45°C, and the mass of the catalyst sprayed in the five regions along the direction from the inlet side to the outlet side is 0.22 mg / cm³. 2 0.21 mg / cm 2 0.2 mg / cm 2 0.19 mg / cm 2 0.18 mg / cm 2 ;

[0099] In five regions separated by the anode side, the catalyst was sequentially sprayed from the outlet side to the inlet side. Spraying was performed under vacuum adsorption at 65°C. The catalyst spraying mass in each of the five regions along the outlet side to the inlet side was 1 mg / cm³. 2 0.9 mg / cm 2 0.8 mg / cm 2 0.7 mg / cm 2 0.6 mg / cm 2 .

[0100] The conductive area 1 is made of copper or beryllium copper, or more specifically, copper. The anode current collector and cathode current collector are both made of copper. The surfaces of the anode current collector and cathode current collector are fully covered with an electroplated layer made of nickel or gold. The anode end plate and cathode end plate are both made of composite resin material.

[0101] The battery stack of this invention is simple to install, reduces process complexity, facilitates industrial mass production, and allows for easy series and parallel stacking of multiple battery stack modules. It also reduces manufacturing and maintenance costs. The battery stack design of this invention avoids the corrosive effect of the original fuel cell airflow on the bipolar plate channels. Calculations and evaluations show that durability is improved by 18% compared to the original design, while also enhancing the battery stack's impact and vibration resistance.

[0102] In another specific embodiment, the present invention provides a fuel cell, such as Figure 6 , Figure 7 As shown, the fuel cell includes the aforementioned battery stack.

[0103] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A bipolar plate for a battery, characterized in that The battery bipolar plate comprises a gas flow guide area and a conductive area, and the gas flow guide area and the conductive area are not in contact; The gas flow guide area is arranged at one end of the battery bipolar plate, and the conductive area is arranged at the other end of the battery bipolar plate in the same plane of the battery bipolar plate; A channel is arranged on the gas flow guide area, and the channel is used for passing gas flow; An outer periphery of the conductive area is provided with a flow channel, and the flow channel is used for passing electrons; The gas flow guide area is made of insulating material.

2. The bipolar plate of claim 1, wherein The thickness of the gas flow guide area is 0.6-1.1 mm.

3. The bipolar plate of claim 1, wherein The insulating material is any one of PPC, PPS, PVC, nylon or composite resin material.

4. The bipolar plate of claim 3, wherein The insulating material is PPC.

5. The bipolar plate of claim 1, wherein The conductive area is made of conductive and heat-conductive material.

6. The bipolar plate of claim 5, wherein The conductive and heat-conductive material is red copper or beryllium copper.

7. The bipolar plate of claim 6, wherein The conductive and heat-conductive material is red copper.

8. The bipolar plate of claim 1, wherein The surface of the conductive area is fully covered with a plating layer.

9. The bipolar plate of claim 8, wherein The material of the plating layer is nickel or gold.

10. A battery stack, characterized by The battery stack comprises an anode end plate, an anode insulating plate, an anode current collector plate, a battery bipolar plate, a non-uniform membrane electrode, a battery bipolar plate, a cathode current collector plate, a cathode insulating plate and a cathode end plate arranged in sequence and is fixed by a fastening device, wherein the battery bipolar plate adopts the battery bipolar plate of any one of claims 1-9.

11. The battery stack of claim 10, wherein, The fastening device is a fastening bolt, and the fastening bolt is arranged at both ends of the battery stack for fixation.

12. The battery stack of claim 10, wherein, The non-uniform membrane electrode is a modular electrode.

13. The battery stack of claim 12, wherein, The non-uniform membrane electrode comprises a reaction area and a conductive area I, the conductive area I is installed corresponding to the conductive area, and the reaction area is installed corresponding to the gas flow guide area.

14. The battery stack of claim 13, wherein, The thickness of the conductive area I is greater than that of the reaction area.

15. The battery stack of claim 13, wherein, The shape of the conductive area I is the same as that of the conductive area.

16. The battery stack of claim 10, wherein, The non-uniform membrane electrode is obtained in the following manner: After the two sides of the membrane electrode are non-uniformized, catalysts are coated on the two sides of the membrane electrode to obtain the non-uniform membrane electrode.

17. The battery stack of claim 16, wherein, The non-uniformization step comprises: dividing the two sides of the membrane electrode into five areas, and spraying the catalysts in the five areas by ultrasonic wave.

18. The battery stack of claim 17, wherein, The two sides of the membrane electrode are a cathode side and an anode side, and both the cathode side and the anode side comprise an inlet side and an outlet side; In the five areas divided on the cathode side, the mass of the catalyst sprayed in the direction from the inlet side to the outlet side decreases in turn; In the five areas divided on the anode side, the mass of the catalyst sprayed in the direction from the outlet side to the inlet side decreases in turn.

19. The battery stack of claim 18, wherein, The conductive area I is made of red copper or beryllium copper.

20. The battery stack of claim 19, wherein, The conductive area I is made of red copper.

21. The battery stack of claim 10, wherein, The anode current collector plate and the cathode current collector plate are both made of red copper.

22. The battery stack of claim 21, wherein, The surfaces of the anode current collector plate and the cathode current collector plate are both fully covered with a plating layer.

23. The battery stack of claim 22, wherein, The material of the plating layer is nickel or gold.

24. The battery stack of claim 10, wherein, The anode end plate and the cathode end plate are both made of composite resin material.

25. A fuel cell, characterized by The fuel cell comprises the battery stack of any one of claims 10-24.

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