Method and system for optimizing the life of a fuel cell system based on thermoelectric ratio adjustment constraints

Abstract

Provided are a method and a system for optimizing the life of a fuel cell system to mitigate the inconsistent situation of performance degradation of a multi-machine system based on a thermoelectric ratio adjustment constraint. 【Solution means】Obtain the initial reference voltage of a plurality of single-unit fuel cell systems, conduct a pre-test of durability performance under normal operating conditions, and obtain the relationship of the change of the reference voltage over time; monitor the operating voltage of the single-unit fuel cell system in real time under normal operating conditions, obtain the real-time monitored voltage and the real-time voltage deviation, and calculate the actual performance degradation situation of the single-unit fuel cell system during normal operation; obtain the predicted performance degradation situation and the available heat quantity when the single-unit fuel cell system operates at different current density points, calculate the boundary of the health state when the single-unit fuel cell system operates stably, and optimize the operating mode of the single-unit fuel cell system.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and specifically relates to a method and a system for optimizing the life of a fuel cell system based on thermoelectric ratio adjustment constraints.

Background Art

[0002] A cogeneration system (MW class) of a large-power fuel cell usually consists of a plurality of fuel cell systems and often faces the following two problems during operation.

[0003] Due to the problem of performance consistency of each system, if the operation continues for a certain period, the performance degradation will be inconsistent. In extreme cases, individual systems will fail and the life of the entire system will be significantly reduced. Therefore, optimization is necessary.

[0004] Adjustment of the electrothermal output ratio of the entire system caused by changes in the demand for thermoelectric loads, that is, some systems may require more heat generation or higher electrical efficiency. Such a dynamic response process may cause deterioration changes in life.

[0005] If performance decay occurs in some systems, it is necessary to perform related load adjustment under dynamic thermoelectric output to ensure the life and stability of the entire multi-device system.

Summary of the Invention

[0006] According to a first aspect of the present invention, the present invention is a method for optimizing the life of a fuel cell system based on thermoelectric ratio adjustment constraints, which is applied to a multi-unit fuel cell system composed of a plurality of single-unit fuel cell systems, Under normal operating conditions, obtaining the initial reference voltage of each single-unit fuel cell system of the multi-unit fuel cell system, performing a durability performance test on the single-unit fuel cell system, and obtaining the relationship between the change over time of the reference voltage of each single-unit fuel cell system; Under the normal operating conditions, monitor in real time the operating voltage in the actual operating process of each single-unit fuel cell system, and obtain the real-time monitored voltage and real-time voltage deviation of each single-unit fuel cell system; Based on the relationship of the reference voltage of each single-unit fuel cell system over time and the real-time monitored voltage, calculate the performance prediction attenuation status of each single-unit fuel cell system during normal operation; Obtain the performance prediction attenuation status and available heat quantity when each single-unit fuel cell system is operating at each current density point, and calculate the boundary of the health state when each single-unit fuel cell system is operating stably; Characterized by including optimizing the operating mode of each single-unit fuel cell system based on the available heat quantity status, performance prediction attenuation status and health state boundary of each single-unit fuel cell system.

[0007] Furthermore, before obtaining the initial reference voltage of each single-unit fuel cell system of the multi-unit fuel cell system under normal operating conditions, it includes the following: The spectrum of the change of the operating conditions of the multi-unit fuel cell system over time is Q output =Σf(C i t i ,C j Q rated ,C k t j ,C m Q rated )(1) Expressed as follows: Here, Q output is the system output power, Q rated is the rated power, Σ is in the form of a combination of addition and subtraction in different operating modes, constitutes the overall operating conditions, f indicates the characteristics of the function in different states, C is the coefficient factor in different states, indicates the value obtained by dividing the output power in a specific state by the rated power, t represents different operating times, the subscripted characters i, j, k of t represent being applied to different operating time ranges, and the subscripted characters i, j, k, m of C represent taking different values at different operating times.

[0008] According to a second aspect of the present invention, the present invention is a system for optimizing the lifespan of a fuel cell system based on thermoelectric ratio adjustment constraints, comprising: one or more processors; a memory storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors perform a method for optimizing the lifespan of a fuel cell system based on thermoelectric ratio adjustment constraints.

[0009] The present invention belongs to the technical field of fuel cells, and specifically relates to a method and a system for optimizing the lifespan of a fuel cell system based on thermoelectric ratio adjustment constraints. The method includes obtaining the initial reference voltages of a plurality of single-unit fuel cell systems, conducting a durability test under normal operating conditions, and obtaining the relationship between the reference voltage and time; monitoring the operating voltage of each single-unit fuel cell system in real time under normal operating conditions, obtaining the real-time monitored voltage and the real-time voltage deviation, and calculating the performance prediction attenuation status of each single-unit fuel cell system during normal operation; calculating the boundary of the health state when each single-unit fuel cell system operates stably based on the current density distribution and the actual heat utilization status during the operation of each single-unit fuel cell system, and optimizing the operating mode of each single-unit fuel cell system. The present invention gradually eliminates the inconsistency of performance attenuation in a multi-unit system and improves the lifespan of a multi-unit fuel cell combined heat and power system under thermoelectric load ratio conditions.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0011] Based on the first embodiment of the present invention, referring to the accompanying drawing 1, the present invention is a method for optimizing the life of a fuel cell system based on a thermoelectric ratio adjustment constraint, which is applied to a multi-unit fuel cell system composed of a plurality of single-unit fuel cell systems, Step S1: Under normal operating conditions, obtain the initial reference voltage of each single-unit fuel cell system in the multi-unit fuel cell system, and conduct a durability test on the single-unit fuel cell system to obtain the relationship between the reference voltage of the single-unit fuel cell system and time; Step S2: Under normal operating conditions, monitor the operating voltage in the actual operating process of each single-unit fuel cell system in real time, and obtain the real-time monitored voltage and the real-time voltage deviation of each single-unit fuel cell system; Step S3: Based on the relationship between the reference voltage of each single-unit fuel cell system and time and the real-time monitored voltage, calculate the performance prediction attenuation situation of each single-unit fuel cell system during normal operation; Step S4: Obtain the performance prediction attenuation situation and the available heat quantity when each single-unit fuel cell system operates at different current density points, and calculate the boundary of the health state when each single-unit fuel cell system operates stably; Step S5: Optimizing the operation mode of each single-unit fuel cell system by using the available heat quantity, predicted performance decay situation, and health state boundary of each single-unit fuel cell system, characterized by including this.

[0012] Furthermore, in Step S1, under normal operating conditions, before obtaining the initial reference voltage of each single-unit fuel cell system in the multi-unit fuel cell system, the following processing is performed. The operating conditions of the multi-unit fuel cell system change over time, and its change spectrum is expressed as follows. Q output =Σf(C i t i ,C j Q rated ,C k t j ,C m Q rated ) (1) Here, Q output is the system output power, Q rated is the rated power, Σ is in the form of a combination of addition and subtraction in different operating modes, and constitutes the overall operating conditions. f indicates the characteristics of the function in different states, C is the coefficient factor in different states, and indicates the value obtained by dividing the output power in a specific state by the rated power. t represents different operating times, the subscripted characters i, j, k of t indicate that they are applied to different operating time ranges, and the subscripted characters i, j, k, m of C indicate that they take different values at different operating times.

[0013] In this embodiment, the operating conditions of the multi-unit fuel cell combined heat and power system are adjusted based on the required electrothermal demand. However, in order to maintain the system life for a long time, generally the frequency of operation adjustment is relatively slow and is adjusted in time units. Therefore, the operating conditions are set gently. However, in the process of setting the operating conditions, it is necessary to consider the actual application scenario. When considering the load fluctuation frequency, it is considered that the operation of a square wave or trapezoidal wave is more appropriate than a triangular wave condition (see Figure 2).

[0014] Furthermore, in step S1, when obtaining the initial reference voltage of each single-unit fuel cell system in the multi-unit fuel cell system under normal operating conditions, the following processing is performed.

[0015] The initial voltage matrix of multiple single-unit fuel cell systems is represented as follows. V initial =[V 1 ,V 2 ,V 3 ,V 4 ···] (2) Here, V initial represents the initial reference voltage of the fuel cell subsystem, and V 1 , V 2 , V 3 , V 4 are the initial reference voltage values in the specified states of the single-unit fuel cell systems numbered 1, 2, 3, and 4. If the initial reference voltage values of each single-unit fuel cell system deviate beyond a preset deviation value from each other, it is necessary to replace the single-unit fuel cell system at the initial stage.

[0016] Furthermore, in step S1, when performing a durability test on the single-unit fuel cell system and obtaining the relationship between the reference voltage of the single-unit fuel cell system and time, the following processing is performed.

[0017] Based on the performance differences of different single-unit fuel cell systems, the corresponding fitting formulas are obtained. In the fitting process, forward and backward difference fitting or linear fitting is used. The predicted voltage V pc matrix of the relationship between the reference voltage of the multi-unit fuel cell system and the operating time is represented as follows. V pc =[M 1 ,M 2 ,M 3 ,M 4 ···] (3) Here, 1, 2, 3, 4 are the numbers of the single-unit systems, and M 1 ,M 2 ,M 3 ,M 4It is the relationship over time between the predicted voltage form and the reference voltage of the single-unit fuel cell systems numbered 1, 2, 3, and 4.

[0018] In this embodiment, based on the operating conditions shown in FIG. 2, other single-unit fuel cell systems of the same lot are subjected to a durability test in advance to obtain the relationship M of the change over time of the reference voltage, and it is used as the input condition of the multi-unit fuel cell system. As shown in FIG. 3, M = -0.0001t + 0.8501, and the fitting formula also varies due to the performance difference between systems. In the fitting process, linear fitting such as forward and backward difference fitting and the least squares method can be used.

[0019] Furthermore, the following processing is included in step S2. Voltage V that monitors in real time the change relationship with the operating time of each single-unit fuel cell system rt The matrix is represented as follows. V rt =[V rt1 ,V rt2 ,V rt3 ,V rt4 ···] (4) Here, 1, 2, 3, and 4 indicate the numbers of the single-unit fuel cell systems. Based on the real-time voltage monitoring result, the predicted voltage V pcn matrix is corrected in real time in the control strategy. V pcn =[M 1 +ε 1 M 1 ,M 2 +ε 2 M 2 ,M 3 +ε 3 M 3 ,M 4 +ε 4 M 4 ···] (5)

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[0020] In this embodiment, referring to FIG. 4, the real-time distribution of the voltage of the fuel cell multi-system is shown. After the No. 2 and No. 8 fuel cell systems are operated, their performance significantly deteriorates, indicating that the No. 2 and No. 8 are single units with poor performance consistency in the multi-system, while the remaining single units show high performance consistency. Therefore, adjust the control strategy early and implement an energy management strategy for the No. 2 and No. 8 in advance to enable the system to operate healthily for a long time.

[0021] Furthermore, step S3 includes the following processes. The predicted voltage V of the relationship between the operating time of the reference voltage of the multi-unit fuel cell system pc matrix, and the predicted voltage V corrected in real time pcn Based on the matrix, the predicted voltage deviation matrix η between each single-unit fuel cell system prt is obtained and used as the predicted performance attenuation situation of each single-unit fuel cell system during normal operation.

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[0022] The predicted performance attenuation rate matrix φ of each single-unit fuel cell system itself prt is calculated.

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[0023] In this embodiment, it is necessary to prevent the performance deviation from becoming large among the single-unit fuel cell systems, and during adjustment, it is also necessary to ensure that in each single-unit fuel cell system, no system shows a large attenuation rate.

[0024] Furthermore, step S4 includes the following processing. The calorific value Q is represented by Equation (11), and the output power P is represented by Equation (12). Q = Q r + Q c (11) Here, Q r represents the heat of reaction, Q c represents the ohmic heat, and both are directly proportional to the current density during the operation process. P = V rt I (12) Here, I represents the magnitude of the current during the operation process, which is obtained by multiplying the current density by the active area. The active area is a known design parameter.

[0025] Extract other single-unit fuel cell systems of the same lot in advance. When each single-unit fuel cell system operates within a preset current density range, for every 0.2 A / cm 2 obtain the predicted voltage matrix V pci showing the change relationship with the operating time of the reference voltage at different current densities.

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[0026] When obtaining Equation (13), the relationship matrix Q p between the actually available heat quantity and the current density is obtained by Equation (14).

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[0027] Using Equation (15), the available heat quantity Q u under normal operating conditions is obtained. Q u = cm u ΔT u (15) Equation (15) is applicable to all single-unit fuel cell systems before adjustment.

[0028] Some single-unit fuel cell systems, after adjusting the operating conditions using Equations (13) and (14), sum up the total heat output of each single-unit fuel cell system to make it u consistent with the total available heat quantity Q

[0029] In this embodiment, the heat generation of the fuel cell mainly consists of two parts: reaction heat and ohmic heat, and the heat generation amount is closely related to the magnitude of the current density. The higher the current density within the selected interval, the greater the heat generation amount of the fuel cell.

[0030] The calorific value Q is directly proportional to the current density. Therefore, the higher the current density, the higher the calorific value. However, as can be seen from Figure 5, the curve of the power density first increases and reaches a peak, and then decreases (on the left and right of the dashed line in Figure 5). Therefore, under the same input power, there are two different current densities corresponding to the left and right of the peak power. That is, two operating modes can be selected under the same output power. When operating on the right side of the peak power, the fuel cell operates at a high current density and the calorific value increases. On the other hand, when operating on the left side of the peak power, the current density of the fuel cell is low, the calorific value is small, and the corresponding voltage in Figure 5 is also high, but the efficiency of the fuel cell at this time is high (the efficiency is the value obtained by dividing the actual voltage by the theoretical voltage, and the theoretical voltage is a known value, for example, 1.23V). Therefore, by adjusting the voltage and calorific value of some systems, the overall thermoelectric output target can be achieved.

[0031] However, under different operating conditions, the lifetimes of multi-unit systems are different. Operating at a low current density, that is, at a high voltage, may have an adverse effect on the system's lifetime (the progress of corrosion is accelerated). When operating at a high current density, it becomes difficult to manage the water and heat of the system, and it may have an adverse effect on the system's lifetime (such as flooding and oxygen deficiency). Furthermore, when performing variable load operation according to Figure 2 (the current density changes due to the diversification of the operating power), it may also have an adverse effect on the system lifetime. The optimal operating state is for the system to operate stably and continuously under relatively appropriate operating conditions.

[0032] Furthermore, step S5 includes the following processing.

[0033] Using the predicted voltage deviation matrix between each single-unit fuel cell system and the predicted performance decay rate deviation matrix of each single-unit fuel cell system itself, adjust the operating mode of each single-unit fuel cell system, and obtain the heat output with the relationship matrix between the actually available heat quantity and the current density as a constraint condition.

[0034] In the real-time voltage deviation matrix between individual fuel cell systems, when the operating conditions of each individual fuel cell system are operating stably, control intervention is performed when the voltage deviation is equal to or greater than a first preset value.

[0035] In this embodiment, from the above analysis, it can be seen that the lifetimes of multi-unit systems are different under different operating states. In order to perform linear fitting and plot slopes and within the same figure, at this time in Equation (13), it is very clear that there are both operating conditions that are better than Equation (3) and those that are worse (see Figure 6). Figure 6 has three additional lines compared to Figure 3. Two dashed lines, one indicates operating conditions better than Equation (3), one indicates operating conditions worse than Equation (3), and the solid line at the top indicates operating conditions better than Equation (3). That is, the predicted voltage determinant (13) includes operating conditions with different attenuation performances.

[0036] Furthermore, step S5 includes the following processing.

[0037] If the performance of some individual fuel cell systems has deteriorated, the following hybrid operation mode is adopted.

[0038] The individual fuel cell systems with deteriorated performance operate under operating conditions with a low attenuation rate calculated by Equation (13). On the other hand, when the total output power or heat quantity is insufficient, one or more individual fuel cell systems with the minimum attenuation calculated by Equation (8) operate under operating conditions of high current density calculated by Equation (13).

[0039] Using Equations (12), (14), and (15), calculate the comprehensive output power and heat output values of the operating currents and output voltages of all necessary individual systems.

[0040] In this embodiment, when some single-unit fuel cell systems operate for a long time under high current density operating conditions, their performance may deteriorate excessively quickly. As a result, a single-unit system with originally good performance may deteriorate excessively. Therefore, when selecting operating conditions, it is necessary to consider the attenuation rate among single-unit systems. Using the prediction results of Equation (8) and Equation (10) as constraints, 120 hours is set as the input time condition. That is, the performance of each single-unit system after operating for 120 hours in this hybrid operation mode is evaluated by prediction. If the prediction result of Equation (8) does not exceed 5% and the prediction result of Equation (10) does not exceed 10%, the combination of the operating conditions is adopted. Otherwise, the operating conditions are adjusted. That is, the selection is performed again using Equation (14). Also, for some single-unit fuel cell systems, after adjusting the operating conditions using Equations (13) and (14), the total heat output of each single-unit fuel cell system needs to u match the total available heat Q

[0041] Furthermore, in the case of a low heat-to-electricity load ratio, the total redundancy of the system is high. That is, as can be seen from Figure 4, the system has a peak output power at a current density of 1.5 A / cm 2 . At this point, the load of the system is not high and full-load operation is not required. Therefore, two operating modes can be selected. The first operating mode: A serious failure occurs and some systems stop operating, or one or more systems with no failure but a significant performance decline stop operating, and the remaining systems with good performance continue to operate. The second operating mode: The entire system operates, and the operating mode of each single-unit fuel cell system is adjusted.

[0042] In the case of a high heat-to-electricity load ratio, the total redundancy of the system is low. As can be seen from Figure 5, for example, when the rated output of a single-unit system is 200 kW, when the actual output of the system exceeds 80% and reaches 160 kW or more, the system is almost close to full-load operation. In this case as well, two operating modes can be selected. First operating mode: When a serious failure occurs in some systems and they stop, the remaining systems with good performance operate at a higher load, but the load demand shall not exceed the maximum output value that the remaining single-unit systems can provide. Second operating mode: When there is no failure in the system, but the performance of some systems has deteriorated, at this time the entire system operates and adjusts the operating modes of each single-unit fuel cell system.

[0043] Based on the second embodiment of the present invention, referring to FIG. 7, the present invention is a life optimization system of a fuel cell system based on a thermoelectric ratio adjustment constraint, one or more processors, a memory storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors execute a method for optimizing the life of a fuel cell system based on a thermoelectric ratio adjustment constraint.

[0044] Those skilled in the art will understand that the content of this disclosure may be accompanied by many variations and improvements. For example, the various devices and components described above may be implemented in hardware, or may be implemented in software, firmware, or some or all combinations thereof.

[0045] In the description of this specification, terms such as "an embodiment", "some embodiments", "exemplary embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics related to the embodiment or example are included in at least one embodiment or example of the present invention. The exemplary expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in one or more embodiments or examples.

Claims

1. A method for optimizing a lifetime of a fuel cell system based on a heat-to-power ratio adjustment constraint, which is applied to a multi-unit fuel cell system composed of a plurality of single-unit fuel cell systems, comprising: Under normal operating conditions, obtain an initial reference voltage of each of the single fuel cell systems of the multi-unit fuel cell system, perform a durability performance test on the single fuel cell systems, and obtain a time-dependent change relationship of the reference voltage of each of the single fuel cell systems; Under the normal operating condition, monitor the operating voltage of each individual fuel cell system in real time during the actual operating process, and obtain the real-time monitored voltage and real-time voltage deviation of each individual fuel cell system; Calculating a performance decay status of each of the single fuel cell systems during normal operation based on the time-varying relationship of the reference voltage of each of the single fuel cell systems and the real-time monitored voltage; Obtaining a performance decay status and a usable heat quantity when each of the single fuel cell systems is operating at each current density point, and calculating a boundary of a health state of each of the single fuel cell systems during stable operation; optimizing an operating mode of each of the single fuel cell systems based on the available heat capacity, the predicted performance decay status, and the health status boundary of each of the single fuel cell systems; Under normal operating conditions, obtaining an initial reference voltage of each single fuel cell system of the multi-fuel cell system also includes: The initial voltage matrix of the plurality of single fuel cell systems is V ｉｎｉｔｉａｌ = [V １ , V ２ , V ３ , V ４ ...] (2) Here, V ｉｎｉｔｉａｌ is the initial reference voltage of the fuel cell subsystem, V １ , V ２ , V ３ , V ４ is an initial reference voltage value when the single fuel cell systems No. 1, No. 2, No. 3, and No. 4 are designated, If the initial reference voltages of the individual fuel cell systems deviate from each other beyond a preset deviation value, the individual fuel cell system must be replaced at an early stage; The test for durability of the single fuel cell system and obtaining the time-dependent change relationship of the reference voltage of the single fuel cell system also include: According to the performance difference of different single fuel cell systems, obtain the corresponding fitting formula; In the fitting process, differential fitting and linear fitting are used to predict the change in the reference voltage of the multi-unit fuel cell system over the operating time. ｐｃ The matrix is V ｐｃ = [M １ , M ２ , M ３ , M ４ ...] (3) Here, 1, 2, 3, and 4 are the numbers of the single system, M １ , M ２ , M ３ , M ４ is the relationship between the predicted voltage type and the reference voltage over time for the single fuel cell systems No. 1, No. 2, No. 3, and No. 4, Under the normal operating condition, monitoring the operating voltage of each individual fuel cell system in real time during the actual operating process, and obtaining the real-time monitored voltage and real-time voltage deviation of each individual fuel cell system also includes: Real-time monitoring of voltage V changes with operating time of each single fuel cell system ｒｔ The matrix is V ｒｔ = [V ｒｔ１ , V ｒｔ２ , V ｒｔ３ , V ｒｔ４ ...] (4) Here, 1, 2, 3, and 4 are the numbers of the individual fuel cell systems. Based on the real-time voltage monitoring situation, the control strategy predicts the voltage V ｐｃｎ Modify the matrix in real time, V ｐｃｎ =[N １ +e １ M １ ,M ２ +e ２ M ２ ,M ３ +e ３ M ３ ,M ４ +e ４ M ４ ・・・](5) [0080] where ε is a correction factor, Real-time voltage deviation η between each single fuel cell system ｒｔ Get the matrix, [0090] where η is the deviation percentage, Calculating the performance decay status of each single fuel cell system during normal operation according to the time-varying relationship of the reference voltage of each single fuel cell system and the real-time monitored voltage also includes: Predicted voltage V of the reference voltage of a multi-unit fuel cell system with respect to the operating time ｐｃ matrix and real-time corrected predicted voltage V ｐｃｎ Using the matrix, the predicted voltage deviation matrix η ｐｒｔ This is used as the performance decay prediction status of each single fuel cell system under normal operating conditions, [0089] The predicted performance decay rate matrix φ of each individual fuel cell system ｐｒｔ Calculate ##EQU00011## As a result, the predicted performance decay rate deviation matrix δ ｐｒｔ Calculate ##EQU00012## Equation (8) represents the performance deviation between the individual fuel cell systems, and equation (10) represents the deviation of the attenuation rate between the individual fuel cell systems. Obtaining the performance decay status and available heat amount of each of the single fuel cell systems when operating at each current density point, and calculating the boundary of the health state of the single fuel cell system when operating in a stable state also includes: The heat generation amount Q is shown in equation (11), and the output power P is shown in equation (12). Q=Q ｒ +Q ｃ (11) Here, Q ｒ is the heat of reaction, Q ｃ is ohmic heat, and both are positively correlated with the current density during operation. P=V ｒｔ I(12) where I is the magnitude of the current during the operation and is equal to the current density multiplied by the active area, the active area being a known design parameter; When each single fuel cell system is operated within a set current density range, it is 0.2 A / cm ２ The relationship of the change over time of the reference voltage at different current densities is predicted by the voltage matrix V ｐｃｉ Obtained as ##EQU00013## Here, the meanings of N, S, and G are the same as those of M in equation (3). When the predicted voltage matrix M of a single fuel cell system with a certain number is adjusted to the form of N, S, and G, the corresponding calculation is equivalently replaced by equation (9), 0.8, 1.0, and 1.2 are the current densities in A / cm ２ and The relationship matrix Q between the amount of heat that can actually be used and the current density ｐ is obtained from equation (14), ##EQU14## where c is the heat capacity of the coolant, a known value determined based on the type of coolant, m is the coolant flow rate, a known quantity read by a flow meter, ΔT is the temperature difference of the coolant at the inlet and outlet of the system, obtained from the readings of the inlet and outlet temperature sensors, and 0.8, 1.0, and 1.2 indicate the magnitude of the current density, in A / cm ２ and Using equation (15), the available heat Q under normal operating conditions is ｕ Seeking Q ｕ =cm ｕ ΔT ｕ (15) Equation (15) applies to all single fuel cell systems before adjustment, m ｕ is the coolant flow rate under normal operating conditions, ΔT ｕ is the coolant temperature difference between the inlet and outlet of the system under normal operating conditions, In some single fuel cell systems, the operating conditions are adjusted using equations (13) and (14), and then the total heat output of each single fuel cell system is added up to obtain the total available heat Q during normal operation before adjustment. ｕ must match Optimizing the operation mode of each of the single fuel cell systems based on the available heat status, the performance-predicted decay status, and the health status boundary of each of the single fuel cell systems also includes: adjusting the operation mode of each of the individual fuel cell systems using a predicted voltage deviation matrix between the individual fuel cell systems and a predicted performance decay rate deviation matrix of each of the individual fuel cell systems themselves, and determining a heat output using the relationship matrix between the actually available heat and the current density as a constraint; In the real-time voltage deviation matrix between the individual fuel cell systems, when the conditions of the individual fuel cell systems are stable operation, an adjustment is intervened when the voltage deviation is equal to or greater than a first preset value; Optimizing the operation mode of each of the single fuel cell systems according to the performance-predicted decay status and the health boundary of each of the single fuel cell systems also includes: When the performance of some of the single fuel cell systems is degraded, a mixed operation mode is adopted, Some of the single fuel cell systems with reduced performance are operated under operating conditions with low decay rates calculated by Equation (13), and when the total output power or heat is insufficient, one or more single fuel cell systems with the lowest decay calculated by Equation (8) are operated at high current densities calculated by Equation (13); Using equations (12), (14) and (15), calculate the total output power and thermal output of all required single system operating currents and output voltages.

2. 2. A method for optimizing a life span of a fuel cell system based on a heat-to-power ratio adjustment constraint as claimed in claim 1, comprising: Before obtaining an initial reference voltage of each single fuel cell system of the multi-fuel cell system under normal operating conditions, the method includes: The spectrum of the change over time in the operating conditions of the multi-unit fuel cell system is Q ｏｕｔｐｕｔ = Σf(C ｉ t ｉ , C ｊ Q ｒａｔｅｄ , C ｋ t ｊ , C ｍ Q ｒａｔｅｄ ) (1), where Q ｏｕｔｐｕｔ is the system output power, Q ｒａｔｅｄ is the rated power, Σ is the combination form of addition and subtraction in different operating modes, which constitutes the overall operating conditions, f indicates the function characteristics in different states, C is the coefficient factor in different states, which indicates the value obtained by dividing the output power in a specific state by the rated power, t represents different operating times, the subscripts i, j, and k of t represent that they apply to different operating time ranges, and the subscripts i, j, k, and m of C represent that they take different values ​​at different operating times.

3. A system for optimizing a lifetime of a fuel cell system based on a heat-to-power ratio adjustment constraint, comprising: one or more processors; A system for optimizing the lifetime of a fuel cell system based on a thermal / power ratio adjustment constraint, comprising: a memory in which one or more programs are stored, the one or more programs being executed by one or more processors, thereby causing the one or more processors to execute the method for optimizing the lifetime of a fuel cell system based on a thermal / power ratio adjustment constraint as described in claim 1 or 2.

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