A fuel cell waste heat recycling method and system based on thermoelectric power generation

Abstract

The present application relates to the technical field of fuel automobile, and specifically provides a fuel cell waste heat recycling method and system based on thermoelectric generation, which utilizes the temperature difference between the fuel cell and the cooling pipeline to generate electricity and supply power for the hydrogen backflow pump; obtains the output voltage value of the thermoelectric generation module, the basic hydrogen flow value of the target object under the current working condition, the reference voltage value and the measured hydrogen concentration value of the tail gas of the target object; obtains the actual required hydrogen flow value of the fuel cell stack according to the output voltage value, the basic hydrogen flow value, the reference voltage value and the measured hydrogen concentration value of the tail gas; adjusts the rotating speed of the hydrogen backflow pump according to the actual required hydrogen flow value, and recycles the hydrogen in the tail gas of the target object and transports it to the inlet of the fuel cell stack. The present application can realize the collaborative management of the precise control of hydrogen flow and the safety of the tail gas, promote the development of the fuel cell system in the direction of high efficiency and safety, improve the hydrogen recycling rate in the tail gas and reduce the exhaust loss.

Description

Technical Field

[0001] This invention relates to the field of fuel cell vehicle technology, and more specifically, to a method and system for recovering and utilizing waste heat from fuel cells based on thermoelectric power generation. Background Technology

[0002] In the commercial electric vehicle sector, fuel cells often generate a large amount of waste heat during operation. This waste heat is usually emitted directly through exhaust gas instead of being recycled, resulting in low energy utilization efficiency.

[0003] The hydrogen demand of fuel cells often fluctuates when vehicle load changes. When the vehicle load decreases, the demand for hydrogen from the fuel cell stack decreases, leading to an oversupply of hydrogen and thus wasting hydrogen. Conversely, when the load increases, the demand for hydrogen increases. If the hydrogen supply is not adjusted accordingly, it may result in insufficient hydrogen supply, incomplete reaction, and affect the performance and stability of the fuel cell, thereby reducing its lifespan.

[0004] For fuel cell systems in commercial electric vehicles, optimizing hydrogen supply and heat utilization strategies can further improve the system's economy and efficiency, extend the lifespan of the fuel cell system, and ensure the stable operation of commercial vehicles under different loads.

[0005] Therefore, it is necessary to develop a method and system for recovering and utilizing waste heat from fuel cells based on thermoelectric power generation, so as to improve the efficiency of waste heat utilization from fuel cells. Summary of the Invention

[0006] Therefore, in order to improve the waste heat utilization efficiency of fuel cells, this invention provides a method and system for recovering and utilizing waste heat from fuel cells based on thermoelectric power generation, the specific technical solution of which is as follows:

[0007] A method for recovering and utilizing waste heat from fuel cells based on thermoelectric power generation includes the following steps:

[0008] A thermoelectric power generation module is installed between the fuel cell and the cooling pipe. The temperature difference between the fuel cell and the cooling pipe is used to drive the thermoelectric power generation module to generate electricity, which powers the hydrogen return pump.

[0009] Obtain the output voltage value of the thermoelectric power generation module, the basic hydrogen flow rate and reference voltage value of the target object under the current operating conditions, and the measured hydrogen concentration value of the tail gas of the target object;

[0010] The actual required hydrogen flow rate for the fuel cell stack is obtained based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value.

[0011] Adjust the speed of the hydrogen return pump according to the actual required hydrogen flow rate to recover the hydrogen in the exhaust gas of the target object and transport it to the inlet of the fuel cell stack.

[0012] The described fuel cell waste heat recovery and utilization method utilizes the temperature difference between the fuel cell's operating process and the cooling pipes to generate electricity from the waste heat produced during fuel cell operation. This provides power support, particularly for the hydrogen recirculation pump, thereby improving the overall energy efficiency of the fuel cell system. Specifically, the method drives the hydrogen recirculation pump, adjusting its speed according to the required hydrogen flow rate. This recovers hydrogen from the exhaust gas and delivers it to the fuel cell stack inlet, optimizing the hydrogen supply and ensuring a match between demand and supply, thus preventing hydrogen waste.

[0013] Furthermore, by obtaining the actual hydrogen flow rate required by the fuel cell stack based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured exhaust hydrogen concentration value, it is possible not only to dynamically optimize the actual hydrogen flow rate required by the fuel cell stack, thereby improving fuel cell efficiency and extending stack life, but also to achieve precise control of hydrogen flow rate and coordinated management of exhaust safety based on the measured exhaust hydrogen concentration value. This will promote the development of fuel cell systems towards high efficiency and safety, improve the hydrogen recovery rate in exhaust gas, and reduce exhaust losses.

[0014] Preferably, the specific method for adjusting the speed of the hydrogen reflux pump according to the actual required hydrogen flow rate includes the following steps:

[0015] PID control parameters are generated based on the voltage difference between the output voltage value and the reference voltage value, and the hydrogen difference between the measured exhaust hydrogen concentration value and the target hydrogen concentration value in the exhaust gas of the target object.

[0016] Adjust the speed of the hydrogen reflux pump according to the PID control parameters.

[0017] Preferably, the actual required hydrogen flow rate value ;

[0018] in, This represents the proportionality coefficient. These represent the output voltage value and the reference voltage value, respectively. This represents the basic hydrogen flow rate. Indicates the nonlinear correction index. This represents the hydrogen concentration correction function for the exhaust gas. This indicates the preset adjustment coefficient. These represent the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value, respectively.

[0019] Preferably, the specific method for obtaining the output voltage value of the thermoelectric power generation module includes the following steps:

[0020] Obtain the number of TEG semiconductor chips in the thermoelectric power generation module;

[0021] The output voltage value is obtained based on the number of TEG semiconductor chips, the temperature difference between the fuel cell and the cooling pipe, and the Seebeck coefficient.

[0022] A fuel cell waste heat recovery and utilization system based on thermoelectric power generation, used to realize the fuel cell waste heat recovery and utilization method as described above, includes:

[0023] A thermoelectric power generation module is installed between the fuel cell and the cooling pipe to generate electricity using the temperature difference between the fuel cell and the cooling pipe, which powers the hydrogen return pump.

[0024] The parameter acquisition module is used to acquire the output voltage value of the thermoelectric power generation module, the basic hydrogen flow rate and reference voltage value of the target object under the current operating conditions, and the measured tail gas hydrogen concentration value of the target object.

[0025] The hydrogen flow rate acquisition module is used to acquire the actual hydrogen flow rate required by the fuel cell stack based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value.

[0026] The control module is used to adjust the speed of the hydrogen return pump according to the actual required hydrogen flow rate, so as to recover the hydrogen in the exhaust gas of the target object and deliver it to the inlet of the fuel cell stack.

[0027] Preferably, the control module includes:

[0028] The PID parameter acquisition unit is used to generate PID control parameters based on the voltage difference between the output voltage value and the reference voltage value, and the hydrogen difference between the measured exhaust hydrogen concentration value and the target hydrogen concentration value in the exhaust gas of the target object.

[0029] The speed adjustment unit is used to adjust the speed of the hydrogen reflux pump according to the PID control parameters.

[0030] Preferably, the hydrogen flow rate acquisition module is based on the formula Obtain the actual required hydrogen flow rate;

[0031] in, This represents the proportionality coefficient. These represent the output voltage value and the reference voltage value, respectively. This represents the basic hydrogen flow rate. Indicates the nonlinear correction index. This represents the hydrogen concentration correction function for the exhaust gas. This indicates the preset adjustment coefficient. These represent the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value, respectively.

[0032] Preferably, the parameter acquisition module obtains the output voltage value based on the number of TEG semiconductor chips in the thermoelectric power generation module, the temperature difference between the fuel cell and the cooling pipe, and the Seebeck coefficient. Attached Figure Description

[0033] The invention will be further understood from the following description taken in conjunction with the accompanying drawings. The components in the drawings are not necessarily drawn to scale, but rather the emphasis is on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0034] Figure 1 This is a schematic diagram of the overall process of a fuel cell waste heat recovery and utilization method based on thermoelectric power generation in one embodiment of the present invention.

[0035] Figure 2 This is a flowchart illustrating a specific method for obtaining the output voltage value of the thermoelectric power generation module in one embodiment of the present invention;

[0036] Figure 3 This is a flowchart illustrating a specific method for adjusting the rotational speed of a hydrogen reflux pump in another embodiment of the present invention.

[0037] Figure 4 This is a schematic diagram of the overall structure of a fuel cell waste heat recovery and utilization system based on thermoelectric power generation in one embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram of a fuel cell waste heat recovery and utilization system based on thermoelectric power generation in another embodiment of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0040] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] In this invention, "first" and "second" do not represent a specific quantity or order, but are merely used to distinguish names.

[0043] In the commercial electric vehicle sector, fuel cells often generate significant amounts of waste heat during operation. This waste heat is typically emitted directly as exhaust gas rather than being recycled, resulting in low energy efficiency. The hydrogen demand of fuel cells fluctuates with changes in vehicle load. When the vehicle load decreases, the fuel cell stack's hydrogen demand drops, leading to a surplus and wasted hydrogen. Conversely, when the load increases, the hydrogen demand rises. If the hydrogen supply is not adjusted accordingly, it may result in insufficient hydrogen supply, incomplete reactions, and negatively impacted fuel cell performance and stability, ultimately reducing its lifespan.

[0044] To address the aforementioned challenges, the waste heat recovery and utilization method and system for fuel cells based on thermoelectric power generation proposed in this invention can be applied in commercial electric vehicles. By optimizing hydrogen supply and heat utilization strategies, the system's economy and efficiency can be further improved, the service life of the fuel cell system can be extended, and the stable operation of commercial vehicles under different loads can be ensured.

[0045] like Figure 1 As shown, an embodiment of the present invention provides a method for recovering and utilizing waste heat from a fuel cell based on thermoelectric power generation, which includes the following steps:

[0046] S1, a thermoelectric power generation module is installed between the fuel cell and the cooling pipe. The temperature difference between the fuel cell and the cooling pipe is used to drive the thermoelectric power generation module to generate electricity to power the hydrogen return pump.

[0047] Specifically, the thermoelectric power generation module includes at least one TEG semiconductor chip, with the hot end in contact with the side of the fuel cell or the coolant outlet, and the cold end in contact with the cooling pipe or the inlet of the fuel cell radiator, forming the maximum temperature gradient.

[0048] S2, obtain the output voltage value of the thermoelectric generator module, the basic hydrogen flow rate and reference voltage value of the target object under the current operating conditions, and the measured hydrogen concentration value of the tail gas of the target object.

[0049] Preferably, such as Figure 2As shown, the specific method for obtaining the output voltage value of the thermoelectric power generation module includes the following steps:

[0050] S21, obtain the number of TEG semiconductor chips in the thermoelectric power generation module;

[0051] S22, the output voltage value is obtained based on the number of TEG semiconductor chips, the temperature difference between the fuel cell and the cooling pipe, and the Seebeck coefficient.

[0052] Specifically, the output voltage value ;in, These represent the number of TEG semiconductor chips, the Seebeck coefficient, and the temperature difference between the fuel cell and the cooling pipe, respectively. The higher the value, the greater the potential for waste heat recovery.

[0053] S3. Obtain the actual required hydrogen flow rate of the fuel cell stack based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value.

[0054] Preferably, the actual required hydrogen flow rate value ;in, This represents the proportionality coefficient. These represent the output voltage value and the reference voltage value, respectively. This represents the basic hydrogen flow rate. Indicates the nonlinear correction index. This represents the hydrogen concentration correction function for the exhaust gas. This indicates the preset adjustment coefficient (generally ranging from 0.1 to 0.3). These represent the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value, respectively.

[0055] For the actual required hydrogen flow rate value It matches the power requirements of the fuel cell stack; for example, it needs to be increased when operating under high load. To increase hydrogen supply. Through dynamic adjustment This can balance the heat generation and cooling requirements of the fuel cell stack, avoiding local overheating or insufficient reaction.

[0056] The proportional coefficient can be understood as the linear gain coefficient of flow regulation, with a value range of 0.8 ≤ ≤1.2. The proportionality coefficient is used to compensate for non-ideal factors in the system (such as pump efficiency fluctuations and changes in pipeline resistance). When the value is >1, accelerate the regulation of hydrogen flow rate in the fuel cell stack. When the value is less than 1, overshoot is suppressed. Specifically, this can be determined through bench testing. The optimal range ensures the system's stability over a wide temperature range.

[0057] The reference voltage value is a preset reference voltage, corresponding to the ideal temperature difference voltage under the design conditions. In PID control, the difference between the reference voltage value and the output voltage value is used to generate a control signal.

[0058] The basic hydrogen flow rate value can be understood as the target hydrogen flow rate under the design operating conditions of the fuel cell, which is determined by parameters such as stack power and hydrogen utilization rate, and is usually expressed in m³. 3 / h (volume flow rate) or kg / h (mass flow rate).

[0059] Specifically, ;in, The stack power, which can be understood as the output power of the fuel cell stack, is measured in watts (W) or kilowatts (kW). It is a core parameter that determines the hydrogen demand; the higher the power, the greater the required hydrogen flow rate. The relationship between stack power and hydrogen demand can be determined through bench tests to optimize system efficiency.

[0060] Hydrogen utilization rate is the efficiency of converting hydrogen into electrical energy in the fuel cell stack. The value range is usually 0.3-0.5. It is used to compensate for the loss of hydrogen that does not participate in the reaction (such as leakage and side reactions) and to adjust the accuracy of flow calculation to avoid insufficient gas supply due to low utilization rate.

[0061] Hydrogen density is the mass-to-volume ratio of hydrogen at a specific temperature and pressure, and is expressed in kg / m³. This represents the portion of the heat released from the complete combustion of hydrogen that can be converted into electrical energy, measured in MJ / kg. The lower calorific value of hydrogen is approximately 120 MJ / kg. It is used to convert the power requirements of the fuel cell stack into hydrogen energy requirements and, combined with hydrogen density, to calculate the energy supply capacity per unit volume of hydrogen.

[0062] According to the law of conservation of energy, the power of the fuel cell stack must be provided by the combustion of hydrogen, that is... The relationship between mass flow rate and volumetric flow rate is: ,in This represents the hydrogen mass flow rate (kg / s). According to the formula... as well as It can be deduced .

[0063] The functional formula for the actual required hydrogen flow rate It can be broken down into two parts: flow regulation term based on temperature difference voltage. and exhaust hydrogen concentration feedback item By introducing a tail gas hydrogen concentration feedback term into the flow regulation term based on temperature difference voltage, dual dynamic control of hydrogen flow rate is achieved, satisfying the following objectives:

[0064] 1. Safety threshold control: Ensure that the hydrogen concentration in the exhaust gas is ≤4%.

[0065] 2. Efficiency optimization: Improve hydrogen recovery rate and reduce tail emission losses.

[0066] 3. System stability: Maintain stack voltage fluctuation <2%.

[0067] When the hydrogen concentration in the exhaust gas is too high, the proportionality coefficient can be appropriately reduced. Preferably, ;in, This represents the preset base value of the scaling factor, ranging from 0.8 to 1.2. express The adjustment coefficient is generally between 0.05 and 0.15. Thus, through the formula... The proportional coefficient can be dynamically adjusted based on the hydrogen concentration in the exhaust gas. .

[0068] By using the functional formula for the actual required hydrogen flow rate, and based on the synergistic effect of variables including the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured exhaust hydrogen concentration value, dynamic optimization of hydrogen flow rate can be achieved, thereby improving fuel cell efficiency and extending stack life.

[0069] S4. Adjust the speed of the hydrogen return pump according to the actual required hydrogen flow rate, recover the hydrogen in the target exhaust gas and transport it to the fuel cell stack inlet.

[0070] Specifically, the speed of the hydrogen reflux pump can be adjusted proportionally according to the actual required hydrogen flow rate.

[0071] The described fuel cell waste heat recovery and utilization method utilizes the temperature difference between the fuel cell's operating process and the cooling pipes to generate electricity from the waste heat produced during fuel cell operation. This provides power support, particularly for the hydrogen recirculation pump, thereby improving the overall energy efficiency of the fuel cell system. Specifically, the method drives the hydrogen recirculation pump, adjusting its speed according to the required hydrogen flow rate. This recovers hydrogen from the exhaust gas and delivers it to the fuel cell stack inlet, optimizing the hydrogen supply and ensuring a match between demand and supply, thus preventing hydrogen waste.

[0072] Furthermore, by obtaining the actual hydrogen flow rate required by the fuel cell stack based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured exhaust hydrogen concentration value, it is possible not only to dynamically optimize the actual hydrogen flow rate required by the fuel cell stack, thereby improving fuel cell efficiency and extending stack life, but also to achieve precise control of hydrogen flow rate and coordinated management of exhaust safety based on the measured exhaust hydrogen concentration value. This will promote the development of fuel cell systems towards high efficiency and safety, improve the hydrogen recovery rate in exhaust gas, and reduce exhaust losses.

[0073] In one embodiment, in step S4, as Figure 3 As shown, the specific method for adjusting the speed of the hydrogen reflux pump according to the actual required hydrogen flow rate includes the following steps:

[0074] S41, PID control parameters are generated based on the voltage difference between the output voltage value and the reference voltage value, and the hydrogen difference between the measured exhaust hydrogen concentration value and the target hydrogen concentration value in the exhaust gas of the target object.

[0075] S42 adjusts the speed of the hydrogen reflux pump according to the PID control parameters.

[0076] like Figure 4 As shown, an embodiment of the present invention also provides a fuel cell waste heat recovery and utilization system based on thermoelectric power generation, used to realize the fuel cell waste heat recovery and utilization method as described above, including a thermoelectric power generation module, a parameter acquisition module, a hydrogen flow acquisition module, and a control module.

[0077] The thermoelectric power generation module is installed between the fuel cell and the cooling pipe to generate electricity using the temperature difference between the fuel cell and the cooling pipe, which powers the hydrogen return pump. The parameter acquisition module is used to acquire the output voltage value of the thermoelectric power generation module, the basic hydrogen flow rate and reference voltage value of the target object under the current operating conditions, and the measured exhaust hydrogen concentration value of the target object.

[0078] Preferably, the hydrogen flow rate acquisition module is based on the formula Obtain the actual required hydrogen flow rate; among which, This represents the proportionality coefficient. These represent the output voltage value and the reference voltage value, respectively. This represents the basic hydrogen flow rate. Indicates the nonlinear correction index. This represents the hydrogen concentration correction function for the exhaust gas. This indicates the preset adjustment coefficient. These represent the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value, respectively.

[0079] The parameter acquisition module obtains the output voltage value based on the number of TEG semiconductor chips in the thermoelectric power generation module, the temperature difference between the fuel cell and the cooling pipe, and the Seebeck coefficient.

[0080] The function formula for the actual required hydrogen flow rate is obtained through the above formula. Based on the synergistic effect of variables including the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value, it can achieve dynamic optimization of hydrogen flow rate, improve fuel cell efficiency, and extend stack life.

[0081] Specifically, the output voltage value ;in, These represent the number of TEG semiconductor chips, the Seebeck coefficient, and the temperature difference between the fuel cell and the cooling pipe, respectively.

[0082] The hydrogen flow acquisition module is used to acquire the actual hydrogen flow rate required by the fuel cell stack based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value; the control module is used to adjust the speed of the hydrogen return pump according to the actual required hydrogen flow rate value, so as to recover the hydrogen in the target tail gas and deliver it to the fuel cell stack inlet.

[0083] Preferably, the control module includes a PID parameter acquisition unit and a speed adjustment unit.

[0084] The PID parameter acquisition unit is used to obtain the output voltage value based on the voltage difference between the output voltage value and the reference voltage value. The hydrogen difference between the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value in the exhaust gas of the target object. PID control parameters are generated; the speed adjustment unit is used to adjust the speed of the hydrogen reflux pump according to the PID control parameters.

[0085] In summary, the fuel cell waste heat recovery and utilization system utilizes the waste heat generated by the fuel cell during operation to generate electricity, particularly powering the hydrogen recirculation pump, thereby improving the overall energy efficiency of the fuel cell system. Specifically, the fuel cell waste heat recovery and utilization method drives the hydrogen recirculation pump, adjusting its speed according to the actual required hydrogen flow rate. This recovers hydrogen from the exhaust gas and delivers it to the fuel cell stack inlet, optimizing the hydrogen supply and ensuring a match between hydrogen demand and supply, thus avoiding hydrogen waste.

[0086] The actual hydrogen flow rate required for the fuel cell stack is obtained by calculating the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured exhaust gas hydrogen concentration value. This not only enables dynamic optimization of the actual hydrogen flow rate required for the fuel cell stack, improving fuel cell efficiency and extending stack life, but also allows for precise control of hydrogen flow rate and coordinated management of exhaust gas safety based on the measured exhaust gas hydrogen concentration value. This promotes the development of fuel cell systems towards high efficiency and safety, improves hydrogen recovery rate in exhaust gas, and reduces exhaust losses.

[0087] In one embodiment, such as Figure 5 As shown, the fuel cell waste heat recovery and utilization system also includes a hydrogen tank, a pressure regulator, a hydrogen concentration sensor, cooling pipes, and a hydrogen-water separator. Hydrogen is extracted from the hydrogen tank and, after appropriate control by the pressure regulator, enters the fuel cell. The electricity generated by the fuel cell stack is supplied to the vehicle load through the control system. Simultaneously, a thermoelectric power generation module utilizes the temperature difference between the fuel cell waste heat and the cooling pipes to generate electricity, driving a hydrogen recirculation pump to recirculate hydrogen from the exhaust gas, thereby achieving waste heat recovery and energy reuse within the fuel cell system.

[0088] The hydrogen recirculation pump is installed in the recirculation pipeline. The hydrogen concentration sensor is installed at the fuel cell stack inlet and in the exhaust gas channel to detect the hydrogen concentration entering the fuel cell and the hydrogen concentration in the exhaust gas. The hydrogen-water separator is used to separate hydrogen and water vapor in the exhaust gas, facilitating the hydrogen recirculation pump to drive the hydrogen in the exhaust gas back to the fuel cell.

[0089] When the load condition changes significantly, the control system activates and adjusts the hydrogen gas flow rate. As the load condition changes, the fuel cell system's hydrogen demand also changes. At this time, data from the hydrogen concentration sensor is collected on the gas discharged from the stack to calculate the required amount of hydrogen to be recovered from the return pipeline to the stack inlet. The required amount of returned hydrogen is compared with the required amount of hydrogen to achieve dynamic adjustment. When the load condition changes from high to low, there is more hydrogen in the return pipeline, and the regulator reduces the hydrogen output from the hydrogen tank; when the load condition changes from low to high, there is less hydrogen in the return pipeline, and the regulator increases the hydrogen output from the hydrogen tank. This control process finely adjusts based on the comparison between the actual hydrogen intake and the required hydrogen volume to ensure a stable hydrogen supply.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for recovering and utilizing waste heat from fuel cells based on thermoelectric power generation, characterized in that, The method for recovering and utilizing waste heat from fuel cells includes the following steps: A thermoelectric power generation module is installed between the fuel cell and the cooling pipe. The temperature difference between the fuel cell and the cooling pipe is used to drive the thermoelectric power generation module to generate electricity, which powers the hydrogen return pump. Obtain the output voltage value of the thermoelectric power generation module, the basic hydrogen flow rate and reference voltage value of the target object under the current operating conditions, and the measured hydrogen concentration value of the tail gas of the target object; The actual required hydrogen flow rate for the fuel cell stack is obtained based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value. Adjust the speed of the hydrogen return pump according to the actual required hydrogen flow rate, recover the hydrogen in the exhaust gas of the target object and transport it to the inlet of the fuel cell stack. The specific method for adjusting the speed of the hydrogen reflux pump according to the actual required hydrogen flow rate includes the following steps: PID control parameters are generated based on the voltage difference between the output voltage value and the reference voltage value, and the hydrogen difference between the measured exhaust hydrogen concentration value and the target hydrogen concentration value in the exhaust gas of the target object. Adjust the speed of the hydrogen reflux pump according to the PID control parameters; The actual required hydrogen flow rate ; in, This represents the proportionality coefficient. These represent the output voltage value and the reference voltage value, respectively. This represents the basic hydrogen flow rate. Indicates the nonlinear correction index. This represents the hydrogen concentration correction function for the exhaust gas. This indicates the preset adjustment coefficient. These represent the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value, respectively.

2. The method for recovering and utilizing waste heat from a fuel cell based on thermoelectric power generation as described in claim 1, wherein the specific method for obtaining the output voltage value of the thermoelectric power generation module includes the following steps: Obtain the number of TEG semiconductor chips in the thermoelectric power generation module; The output voltage value is obtained based on the number of TEG semiconductor chips, the temperature difference between the fuel cell and the cooling pipe, and the Seebeck coefficient.

3. A waste heat recovery and utilization system for fuel cells based on thermoelectric power generation, characterized in that, include: A thermoelectric power generation module is installed between the fuel cell and the cooling pipe to generate electricity using the temperature difference between the fuel cell and the cooling pipe, which powers the hydrogen return pump. The parameter acquisition module is used to acquire the output voltage value of the thermoelectric power generation module, the basic hydrogen flow rate and reference voltage value of the target object under the current operating conditions, and the measured tail gas hydrogen concentration value of the target object. The hydrogen flow rate acquisition module is used to acquire the actual hydrogen flow rate required by the fuel cell stack based on the output voltage value, the basic hydrogen flow rate value, the reference voltage value, and the measured tail gas hydrogen concentration value. The control module is used to adjust the speed of the hydrogen return pump according to the actual required hydrogen flow rate, so as to recover the hydrogen in the exhaust gas of the target object and deliver it to the fuel cell stack inlet. The control module includes: The PID parameter acquisition unit is used to generate PID control parameters based on the voltage difference between the output voltage value and the reference voltage value, and the hydrogen difference between the measured exhaust hydrogen concentration value and the target hydrogen concentration value in the exhaust gas of the target object. The speed adjustment unit is used to adjust the speed of the hydrogen reflux pump according to the PID control parameters; The hydrogen flow rate acquisition module is based on the formula Obtain the actual required hydrogen flow rate; in, Represents the proportionality coefficient. These represent the output voltage value and the reference voltage value, respectively. This represents the basic hydrogen flow rate. Indicates the nonlinear correction index. This represents the hydrogen concentration correction function for the exhaust gas. This indicates the preset adjustment coefficient. These represent the measured hydrogen concentration value in the exhaust gas and the target hydrogen concentration value, respectively.

4. The fuel cell waste heat recovery and utilization system based on thermoelectric power generation as described in claim 3, wherein the parameter acquisition module acquires the output voltage value based on the number of TEG semiconductor chips in the thermoelectric power generation module, the temperature difference between the fuel cell and the cooling pipe, and the Seebeck coefficient.

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