A methanol reforming fuel cell system based on an independent cold start path and its operating method

Abstract

This invention discloses a methanol reforming fuel cell system and its operating method based on an independent cold-start path, belonging to the field of fuel cell vehicle energy technology. This system, designed for cold-region applications, innovatively employs a dedicated cold-start path comprised of components such as a catalytic combustion chamber. In frigid environments around -30°C, catalytic combustion is initiated via this path, generating heat that directly provides the necessary start-up heat for the high-temperature proton exchange membrane fuel cell, while simultaneously preheating the fuel evaporation chamber and reforming chamber. This overcomes the bottleneck of low chemical reaction rates at low temperatures, achieving rapid cold start. After the system stabilizes, it switches to the main power generation path, and the fuel cell exhaust gas is treated in the catalytic combustion chamber, achieving energy recycling and near-zero pollutant emissions. This invention effectively solves the difficulties of cold start-up and exhaust gas pollution in methanol reforming fuel cells in cold regions, with a wide operating temperature range (-30°C to 40°C), making it suitable for methanol fuel cell vehicles.

Description

Technical Field

[0001] This invention relates to the field of fuel cell vehicle technology, and specifically to an integrated device and method for methanol reforming fuel cell vehicles that combines cold start assistance and exhaust gas treatment functions. Background Technology

[0002] Methanol, as a "liquid sunshine" fuel that is safe to store and transport, inexpensive, and can be synthesized from renewable energy sources, is an ideal fuel alternative. Methanol reforming fuel cell vehicles, which use methanol as a hydrogen source, combine the high energy density of methanol with the high efficiency of fuel cells and are considered one of the important technological pathways to achieve carbon neutrality in the transportation sector, especially suitable for commercial vehicles and long-distance transportation scenarios.

[0003] However, the promotion of these vehicles in cold regions faces two major technical bottlenecks: First, the severe challenge of cold start. In temperatures of -30°C and below, the rates of methanol reforming for hydrogen production and the electrochemical reaction in the fuel cell drop drastically, and the catalyst activity becomes almost inactive, leading to vehicles failing to start normally or experiencing excessively long start-up times. Existing technologies often employ external heating or complex waste heat management strategies, but these often suffer from slow response, high energy consumption, and system complexity. Second, there is the issue of exhaust emissions. The reforming reaction is not a complete conversion; its exhaust contains 1%-5% unburned methanol and intermediate products such as formaldehyde. Direct emission of these substances would cause environmental pollution and energy waste.

[0004] Currently, while researchers have attempted to improve low-temperature performance by optimizing catalysts and refining stack design, their efforts are largely focused on the components themselves, lacking a fundamental solution to the cold-start problem at the system architecture level. For example, some solutions separate the start-up preheating system from the exhaust gas treatment system, resulting in a complex system, difficult thermal management, and slow response. Therefore, there is an urgent need for a highly integrated system solution with embedded rapid cold-start capabilities to promote the commercial application of methanol reforming fuel cell vehicles under all-climate conditions. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to overcome the shortcomings of the prior art and provide a methanol reforming fuel cell system based on an independent cold start path. This system can achieve rapid start-up and efficient operation within a wide temperature range of -30℃ to 40℃, while simultaneously solving the problem of exhaust gas treatment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a methanol reforming fuel cell system based on an independent cold start path. The system includes a methanol aqueous solution storage tank, a first fuel pump, a first gas pump, a catalytic combustion chamber, a second gas pump, a heat exchanger, a high-temperature proton exchange membrane fuel cell, a second fuel pump, a fuel evaporation chamber, a reforming chamber, a load, and a lithium battery. The system consists of three functional paths: Cold start path: The outlet of the methanol-water solution storage tank is connected to the fuel inlet of the catalytic combustion chamber via the first fuel pump; the air outlet of the first air pump is connected to the air inlet of the catalytic combustion chamber; the combustion products outlet of the catalytic combustion chamber is discharged after passing through the hot side flow channel of the heat exchanger; the lithium battery supplies power to the first fuel pump and the first air pump. Main power generation path: The outlet of the methanol aqueous solution storage tank is connected to the fuel evaporation chamber and the reforming chamber in sequence through the second fuel pump, and then connected to the anode inlet of the high-temperature proton exchange membrane fuel cell; the power output terminal of the high-temperature proton exchange membrane fuel cell is connected to the load and the lithium battery; Thermal cycle and exhaust gas treatment path: The anode exhaust gas outlet of the high-temperature proton exchange membrane fuel cell is connected to the exhaust gas inlet of the catalytic combustion chamber; the air outlet of the second air pump is connected to the cold side flow channel inlet of the heat exchanger, and the cold side flow channel outlet of the heat exchanger is connected to the cathode inlet of the high-temperature proton exchange membrane fuel cell. The catalytic combustion chamber provides preheating heat energy to the fuel evaporation chamber and the reforming chamber through heat conduction.

[0007] More preferably, the system of the present invention operates at an ambient temperature of -30°C to 40°C.

[0008] More preferably, the catalytic combustion chamber of the present invention is loaded with a noble metal catalyst for achieving low-temperature catalytic combustion of methanol.

[0009] More preferably, the heat exchanger of the present invention is a plate-fin heat exchanger.

[0010] More preferably, the system of the present invention further includes a preheater disposed on the pipeline between the first fuel pump, the first air pump and the catalytic combustion chamber, for preheating the fuel and air entering the catalytic combustion chamber, and the preheater is powered by the lithium battery.

[0011] More preferably, the system of the present invention further includes a control system, the control system being configured to: When the ambient temperature is below a set threshold, the cold start path is activated, and the heat energy generated by the catalytic combustion chamber is prioritized for rapid heating of the high-temperature proton exchange membrane fuel cell, fuel evaporation chamber, and reforming chamber. When the fuel evaporation chamber and the reforming chamber reach their set operating temperatures, the main power generation path is activated, and the operation of the cold start path is gradually reduced or shut down.

[0012] More preferably, the fuel evaporation chamber of the present invention reaches 120-150°C, and the reforming chamber reaches 200-300°C.

[0013] Based on the same inventive concept, the present invention also provides a method for operating the system described in any of the above claims, the method comprising the following steps: Cold start procedure: In a low-temperature environment, the cold start path consisting of the first fuel pump, the first air pump, the catalytic combustion chamber and the lithium battery is started; methanol aqueous solution and air are introduced into the catalytic combustion chamber to carry out catalytic combustion reaction. The heat energy released by the reaction directly provides start-up heat energy for the high-temperature proton exchange membrane fuel cell through the heat exchanger, and at the same time preheats the fuel evaporation chamber and the reforming chamber through heat conduction. Reforming power generation steps: When the fuel evaporation chamber and the reforming chamber reach the set temperature, the main power generation path consisting of the second fuel pump is started; the methanol aqueous solution is transported to the fuel evaporation chamber for vaporization, and the vaporized methanol vapor enters the reforming chamber for water vapor reforming reaction to generate hydrogen. The hydrogen is then introduced into the high-temperature proton exchange membrane fuel cell to generate electricity, which supplies the load and charges the lithium battery. Thermal cycling and exhaust gas treatment steps: The anode exhaust gas discharged from the high-temperature proton exchange membrane fuel cell is introduced into the catalytic combustion chamber for reaction to achieve purification; at the same time, ambient air is pumped into the cold side of the heat exchanger through a second air pump to absorb the waste heat of the exhaust gas discharged from the catalytic combustion chamber, and the preheated air enters the cathode of the high-temperature proton exchange membrane fuel cell.

[0014] More preferably, in the cold start step of the present invention, the catalytic combustion reaction is the main heat source for the system to achieve rapid start-up at -30°C.

[0015] Based on the same inventive concept, the present invention also provides a vehicle that integrates a methanol reforming fuel cell system as described in any of the above descriptions.

[0016] The beneficial effects of this invention are as follows: This invention achieves rapid start-up and efficient operation across a wide temperature range through a unique system architecture design. The system employs an independent cold start path, rapidly establishing a high-temperature heat source through catalytic combustion, effectively solving the start-up challenge in extremely cold environments. Simultaneously, the system integrates exhaust gas treatment and energy recovery, offering advantages such as compact structure, rapid response, and high energy utilization, providing reliable technical support for the all-weather application of methanol reforming fuel cell vehicles. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the methanol reforming fuel cell system described in this invention.

[0019] Among them, 1-methanol-water solution storage tank, 2-first fuel pump, 3-first gas pump, 4-catalytic combustion chamber, 5-second gas pump, 6-heat exchanger, 7-high temperature proton exchange membrane fuel cell, 8-second fuel pump, 9-fuel evaporation chamber, 10-reforming chamber, 11-load, 12-lithium battery. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0021] Example 1, Combination Figure 1 This embodiment describes a methanol reforming fuel cell system suitable for vehicles operating in cold regions. The system is designed to operate within a temperature range of -30°C to 40°C and can achieve rapid start-up in extremely cold environments.

[0022] like Figure 1 As shown, the connection relationships of the various components of the system are as follows: The outlet of the methanol-water solution storage tank 1 is divided into two paths: the first path is connected to the fuel inlet of the catalytic combustion chamber 4 via the first fuel pump 2; the second path is connected to the fuel evaporation chamber 9 and the reforming chamber 10 in sequence via the second fuel pump 8. The air outlet of the first air pump 3 is connected to the air inlet of the catalytic combustion chamber 4. The combustion product outlet of the catalytic combustion chamber 4 is connected to the hot side channel of the heat exchanger 6. The hydrogen outlet of the reforming chamber 10 is connected to the anode inlet of the high-temperature proton exchange membrane fuel cell 7. The anode exhaust outlet of the high-temperature proton exchange membrane fuel cell 7 is connected to the exhaust inlet of the catalytic combustion chamber 4. The air outlet of the second air pump 5 is connected to the cold side channel inlet of the heat exchanger 6, and the cold side channel outlet of the heat exchanger 6 is connected to the cathode inlet of the high-temperature proton exchange membrane fuel cell 7. The power output terminal of the high-temperature proton exchange membrane fuel cell 7 is connected to the load 11 and the lithium battery 12.

[0023] Through the connection of the above components, the system of the present invention constitutes three functional paths: Cold start path: The outlet of the methanol-water solution storage tank 1 is connected to the fuel inlet of the catalytic combustion chamber 4 through the first fuel pump 2; the air outlet of the first air pump 3 is connected to the air inlet of the catalytic combustion chamber 4; the combustion products outlet of the catalytic combustion chamber 4 is discharged after passing through the hot side channel of the heat exchanger 6; the lithium battery 12 supplies power to the first fuel pump 2 and the first air pump 3. Main power generation path: The outlet of the methanol aqueous solution storage tank 1 is connected to the fuel evaporation chamber 9 and the reforming chamber 10 in sequence through the second fuel pump 8, and then connected to the anode inlet of the high-temperature proton exchange membrane fuel cell 7; the power output terminal of the high-temperature proton exchange membrane fuel cell 7 is connected to the load 11 and the lithium battery 12; Thermal cycle and exhaust gas treatment path: The anode exhaust gas outlet of the high-temperature proton exchange membrane fuel cell 7 is connected to the exhaust gas inlet of the catalytic combustion chamber 4; the air outlet of the second air pump 5 is connected to the cold side flow channel inlet of the heat exchanger 6, and the cold side flow channel outlet of the heat exchanger 6 is connected to the cathode inlet of the high-temperature proton exchange membrane fuel cell 7. Furthermore, in this embodiment, the catalytic combustion chamber 4 is loaded with a Pd-Ce / γ-Al2O3 honeycomb ceramic catalyst, whose methanol ignition temperature is approximately 140°C. The heat exchanger 6 adopts a compact plate-fin structure to achieve efficient heat exchange within a limited space. The lithium battery 12 is a high-power lithium polymer battery used to provide power during the start-up phase.

[0024] Furthermore, the working principle and process of this invention are as follows: (1) Cold start procedure: In a low-temperature environment, the lithium battery 12 initially powers the first fuel pump 2 and the first air pump 3. Methanol-water solution and air are supplied to the inlet of the catalytic combustion chamber 4, where they are preheated using a preheater. After entering the catalytic combustion chamber 4, the mixture undergoes catalytic combustion on the catalyst surface, rapidly releasing a large amount of heat energy. This high-temperature flue gas flows through the hot side of the heat exchanger 6, transferring its heat to the air flowing through the cold side. The heated air enters the cathode of the high-temperature proton exchange membrane fuel cell 7, providing it with the heat required for initial heating. Simultaneously, the catalytic combustion chamber 4 directly transfers heat to the fuel evaporation chamber 9 and the reforming chamber 10 through heat conduction, causing their temperatures to gradually rise. During this stage, the second fuel pump 8 is in a closed state.

[0025] (2) Restructuring power generation steps: When the temperature sensor detects that the temperature of the fuel evaporation chamber 9 reaches approximately -120°C, the reforming chamber 10 reaches approximately 250°C, and the high-temperature proton exchange membrane fuel cell 7 reaches its minimum operating temperature, the second fuel pump 8 is activated. A methanol-water solution is delivered to the preheated fuel evaporation chamber 9, where the liquid methanol-water solution absorbs heat and rapidly vaporizes into methanol vapor. The vaporized methanol vapor enters the reforming chamber 10, where a steam reforming reaction occurs under the action of a reforming catalyst, generating reformed gas, primarily composed of hydrogen. The resulting hydrogen-rich gas enters the preheated anode of the high-temperature proton exchange membrane fuel cell 7, participating in an electrochemical reaction to generate electricity. The generated electrical energy is used to power the load 11 and to charge the lithium battery 12.

[0026] (3) Heat circulation and exhaust gas treatment steps: After the system is operating stably, the anode exhaust gas discharged from the high-temperature proton exchange membrane fuel cell 7 is introduced into the catalytic combustion chamber 4, where the combustible components in the exhaust gas are completely oxidized, thus purifying the exhaust gas. Simultaneously, the high-temperature exhaust gas discharged from the catalytic combustion chamber 4 flows through the hot side of the heat exchanger 6 and exchanges heat with the low-temperature ambient air pumped in from the second air pump 5. This preheated air is then sent to the cathode of the high-temperature proton exchange membrane fuel cell 7, further improving the overall thermal efficiency of the system.

[0027] Preferably, the system further includes an intelligent control system, which is connected to the temperature sensors, flow sensors, fuel pump, and air pump to execute the aforementioned phased control logic, ensuring the system's rapid and stable startup and efficient and clean operation.

[0028] In summary, this invention, through its unique system architecture and integrated thermal management design, achieves efficient and stable operation of a methanol reforming high-temperature proton exchange membrane fuel cell system across a wide temperature range and all climate conditions. Its core effects are reflected in the following aspects: Rapid and reliable start-up in extremely cold environments: The system is designed with an independent catalytic combustion cold start path, which can quickly establish a high-temperature heat source in low-temperature environments through the catalytic combustion reaction of methanol / air without relying on an external heat source. This high-temperature heat is simultaneously heated to the reforming reaction chamber and fuel cell stack through a dual channel of direct conduction and air preheating, effectively overcoming the problems of slow start-up, high energy consumption, or even inability to start up in traditional systems under extremely cold conditions, and achieving rapid and self-sustaining cold start-up.

[0029] High-efficiency integration and cascaded energy utilization: The system achieves deep coupling of chemical reaction, power generation, and waste heat recovery. The catalytic combustion chamber serves as both the initial heat source for cold start and a purification unit for treating anode exhaust gas during steady-state operation, achieving two goals at once. Waste heat from the high-temperature exhaust gas is recovered through a heat exchanger to preheat the air entering the fuel cell cathode, significantly improving the overall thermal efficiency of the system. This cascaded utilization and internal circulation of "fuel chemical energy - thermal energy - electrical energy" maximizes energy utilization.

[0030] Compact and integrated structural design: Core modules such as fuel evaporation, reforming, catalytic combustion, stack and heat exchange are highly integrated. Heat is efficiently transferred and managed through direct conduction between chambers and flow channel design, reducing complex external pipelines and independent heating components, making the system structure more compact and reliable, and improving power density.

[0031] Clean and environmentally friendly with near-zero emissions: The system introduces all the anode exhaust gas, containing unreacted hydrogen and other combustible components, from the high-temperature proton exchange membrane fuel cell into the catalytic combustion chamber for complete oxidation, converting it into water and carbon dioxide. This process not only achieves harmless treatment of the exhaust gas and eliminates the risk of direct hydrogen emissions, but also recovers the chemical energy of the remaining fuel in the exhaust gas, making the system's emissions clean and environmentally friendly.

[0032] Providing an all-weather solution for automotive applications: This solution effectively resolves the contradiction between the stringent operating temperature requirements and environmental adaptability of methanol reforming fuel cells. Its rapid self-start capability, efficient and stable operation, and compact integrated design make it particularly suitable for use as a power source or auxiliary power source in vehicles. This provides crucial technical support for the commercialization of methanol reforming fuel cell technology in new energy vehicles, especially in commercial vehicles that need to cope with extreme cold climates.

[0033] The above description of the technical solution provided by the present invention through several specific embodiments is intended to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above-described specific embodiments are not intended to limit the present invention. Any reasonable modifications and improvements to the present invention, reasonable combinations of implementation methods and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A methanol reforming fuel cell system based on an independent cold-start path, characterized in that, The system includes a methanol-water solution storage tank (1), a first fuel pump (2), a first gas pump (3), a catalytic combustion chamber (4), a second gas pump (5), a heat exchanger (6), a high-temperature proton exchange membrane fuel cell (7), a second fuel pump (8), a fuel evaporation chamber (9), a reforming chamber (10), a load (11), and a lithium battery (12). The system consists of three functional paths: Cold start path: The outlet of the methanol aqueous solution storage tank (1) is connected to the fuel inlet of the catalytic combustion chamber (4) through the first fuel pump (2); the air outlet of the first air pump (3) is connected to the air inlet of the catalytic combustion chamber (4); the combustion product outlet of the catalytic combustion chamber (4) is discharged after passing through the hot side channel of the heat exchanger (6); the lithium battery (12) supplies power to the first fuel pump (2) and the first air pump (3); Main power generation path: The outlet of the methanol aqueous solution storage tank (1) is connected to the fuel evaporation chamber (9) and the reforming chamber (10) in sequence through the second fuel pump (8), and then connected to the anode inlet of the high-temperature proton exchange membrane fuel cell (7); the power output terminal of the high-temperature proton exchange membrane fuel cell (7) is connected to the load (11) and the lithium battery (12). Thermal cycle and exhaust gas treatment path: The anode exhaust gas outlet of the high-temperature proton exchange membrane fuel cell (7) is connected to the exhaust gas inlet of the catalytic combustion chamber (4); the air outlet of the second air pump (5) is connected to the cold side flow channel inlet of the heat exchanger (6), and the cold side flow channel outlet of the heat exchanger (6) is connected to the cathode inlet of the high-temperature proton exchange membrane fuel cell (7). The catalytic combustion chamber (4) provides preheating heat energy to the fuel evaporation chamber (9) and the reforming chamber (10) through heat conduction.

2. The system according to claim 1, characterized in that, The system operates in an ambient temperature range of -30°C to 40°C.

3. The system according to claim 1, characterized in that, The catalytic combustion chamber (4) is loaded with a noble metal catalyst for achieving low-temperature catalytic combustion of methanol.

4. The system according to claim 1, characterized in that, The heat exchanger (6) is a plate-fin heat exchanger.

5. The system according to claim 1, characterized in that, The system also includes a preheater, which is installed on the pipeline between the first fuel pump (2), the first air pump (3) and the catalytic combustion chamber (4) for preheating the fuel and air entering the catalytic combustion chamber. The preheater is powered by the lithium battery (12).

6. The system according to claim 1, characterized in that, The system also includes a control system configured to: When the ambient temperature is below the set threshold, the cold start path is activated, and the heat energy generated by the catalytic combustion chamber (4) is preferentially used to rapidly heat up the high-temperature proton exchange membrane fuel cell (7), the fuel evaporation chamber (9), and the reforming chamber (10). When the fuel evaporation chamber (9) and the reforming chamber (10) reach their set operating temperatures, the main power generation path is started, and the operation of the cold start path is gradually reduced or shut down.

7. The system according to claim 5, characterized in that, The set operating temperature is: the fuel evaporation chamber (9) reaches 120-150℃, and the reforming chamber (10) reaches 200-300℃.

8. A method for operating the system according to any one of claims 1-7, characterized in that, The method includes the following steps: Cold start procedure: In a low temperature environment, start the cold start path consisting of the first fuel pump (2), the first air pump (3), the catalytic combustion chamber (4) and the lithium battery (12); introduce methanol aqueous solution and air into the catalytic combustion chamber (4) for catalytic combustion reaction, and the heat energy released by the reaction directly provides start-up heat energy to the high-temperature proton exchange membrane fuel cell (7) through the heat exchanger (6), and at the same time preheats the fuel evaporation chamber (9) and the reforming chamber (10) through heat conduction; Reforming power generation steps: When the fuel evaporation chamber (9) and the reforming chamber (10) reach the set temperature, the main power generation path consisting of the second fuel pump (8) is started; the methanol aqueous solution is transported to the fuel evaporation chamber (9) for vaporization, and the vaporized methanol vapor enters the reforming chamber (10) for water vapor reforming reaction to generate hydrogen. The hydrogen is passed into the high-temperature proton exchange membrane fuel cell (7) to generate electricity, and the generated electricity supplies the load (11) and charges the lithium battery (12); Thermal cycling and exhaust gas treatment steps: The anode exhaust gas discharged from the high-temperature proton exchange membrane fuel cell (7) is introduced into the catalytic combustion chamber (4) for reaction to achieve purification; at the same time, ambient air is pumped into the cold side of the heat exchanger (6) by the second air pump (5) to absorb the residual heat of the exhaust gas discharged from the catalytic combustion chamber, and the preheated air enters the cathode of the high-temperature proton exchange membrane fuel cell (7).

9. The method according to claim 8, characterized in that, In the cold start step, the catalytic combustion reaction is the main heat source for the system to achieve rapid start-up at -30°C.

10. A vehicle, characterized in that, It integrates a methanol reforming fuel power system as described in any one of claims 1-7.

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