Method for power distribution in a multi-stack fuel cell system based on stack degradation consistency

Abstract

The application provides a power distribution method for a multi-stack fuel cell system based on stack degradation consistency, mainly reduces hydrogen consumption of the multi-stack fuel cell system, improves economy of the multi-stack fuel cell system, delays voltage degradation of the multi-stack fuel cell system and prolongs service life; the application constructs a multi-stack fuel cell system and a stack degradation model, determines the optimal number of stacks online according to demand power at the current time, and determines power distributed to each stack; the application starts the optimal number of stacks under the premise of meeting the power demand, and makes the stacks work near the optimal efficiency point, thereby improving the economy of the multi-stack fuel cell system; meanwhile, the application guarantees the consistency of stack degradation after long-time operation, thereby prolonging the service life of the multi-stack fuel cell system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuel cells, and particularly relates to a multi-stack fuel cell system power distribution method based on stack degradation consistency. BACKGROUND

[0002] With the continuous development of the aviation industry, the proportion of aviation industry in total carbon emissions is also increasing, and by 2050, the aviation industry's carbon dioxide emissions will account for more than 25% of global emissions. Developing new energy green aviation is an inevitable choice to achieve efficient and sustainable development of the aviation industry. Fuel cell systems have been widely concerned due to their clean and pollution-free characteristics, high power density, and have become one of the potential development directions of aviation electric propulsion systems. The fuel cell system applied to small-power aircraft such as unmanned aerial vehicles mainly consists of fuel cell stacks, auxiliary energy storage elements and matching converters. However, the low fault tolerance, durability and operating efficiency of single-stack fuel cell systems restrict their application in high-power electric propulsion systems. Compared with single-stack systems, multi-stack fuel cell systems have higher flexibility, providing greater output power and superior system performance, as well as a wider efficient working area and more flexible power distribution method.

[0003] Traditional multi-stack fuel cell system power distribution strategies include chain distribution strategy and average distribution strategy. The core of chain distribution strategy is to minimize the number of working stacks and distribute power in order according to the required power level. When the current stack reaches the maximum output power, the next stack is started until the load demand power is reached or all stacks are started. The average distribution strategy is to distribute the demand power equally to each stack when the number of stacks in use is constant. At this time, each stack operates for the same time, and the load power and power fluctuation are also the same.

[0004] The traditional strategy in the prior art is not suitable for complex working conditions, and it is difficult to achieve optimal control of the multi-stack fuel cell system, and the hydrogen consumption of the multi-stack fuel cell system is high. Chain distribution strategy only has the first stack reaching maximum efficiency, and with the increase of the number of started stacks, the system efficiency decreases significantly; the average distribution strategy still starts all stacks in the low power interval and makes each stack run at a lower power, resulting in low system efficiency. The above two strategies are not conducive to reducing hydrogen consumption, resulting in poor system economy; at the same time, the prior art does not consider the multi-objective optimization problem of real-time optimal online number of stacks and stack voltage degradation consistency of the multi-stack fuel cell system; the online working number will affect the subsequent power distribution and hydrogen consumption of the multi-stack fuel cell system, and the inconsistent stack degradation will also affect the service life of the system. Therefore, a multi-stack fuel cell system power distribution method is needed to achieve optimal control according to the target power demand.

[0005] In order to solve the above problems, the application provides a multi-stack fuel cell system power distribution method based on stack degradation consistency, which can start the optimal number of stacks under the premise of meeting the power demand, make them work near the optimal efficiency point, improve the system economy, delay the voltage degradation, ensure the consistency of the degradation of each stack after a long time of operation, and prolong the service life of the system. SUMMARY

[0006] In order to overcome the shortcomings of the prior art, reduce the hydrogen consumption of the multi-stack fuel cell system, improve the economy of the multi-stack fuel cell system, delay the voltage degradation of the multi-stack fuel cell system, and prolong the service life, the application provides a multi-stack fuel cell system power distribution method based on stack degradation consistency.

[0007] The multi-stack fuel cell system power distribution method based on stack degradation consistency comprises the following steps:

[0008] Step 1: Construct a multi-stack fuel cell system;

[0009] The multi-stack fuel cell system comprises N parallel fuel cells; each fuel cell is identical; each fuel cell comprises a stack, an auxiliary energy storage element, and a boost converter; each stack is connected to a DC bus through a boost converter;

[0010] Step 2: Establish a stack degradation model based on the multi-stack fuel cell system;

[0011] The stack degradation model comprises a stack output voltage, a stack aging drop voltage, a stack standby degradation voltage, a stack switching degradation voltage, and a stack total degradation voltage;

[0012] Step 3: Determine the optimal number of online stacks according to the demand power at the current time;

[0013] Step 4: Select the stacks in the multi-stack fuel cell system according to the optimal number of online stacks to obtain a “start” set and a “standby” set, n k stacks in the “start” set are the stacks that should be started at time k;

[0014] Step 5: Calculate the power borne by each stack in the “start” set according to the optimal number of online stacks and the stacks in the “start” set.

[0015] Further, the stack output voltage is:

[0016] (1)

[0017] In the formula, is the Nernst voltage, is the activation loss of the stack, is the ohmic loss of the stack, is the concentration difference loss of the stack;

[0018] the stack aging down voltage is:

[0019] (2)

[0020] wherein is the running time, the unit of the running time is h, is the first aging coefficient; is the second aging coefficient, the value of is -7.339x10 -6 ; the value of is -1.594x10 -2 ;

[0021] the stack standby decay voltage is:

[0022] (3)

[0023] wherein is the decay rate, the value of the decay rate is 8.662 , is the standby time;

[0024] the stack switching decay voltage is , =0.4185 ;

[0025] the total decay voltage of the stack is:

[0026] (4)

[0027] wherein, is the number of state transitions.

[0028] Further, the process of determining the optimal number of stacks online is:

[0029] the demand power at k moment is P k , the ratio n of the demand power at k moment and the optimal power corresponding to the optimal efficiency point of the fuel cell is calculated:

[0030] (5)

[0031] wherein P opt is the optimal power corresponding to the optimal efficiency point of the fuel cell;

[0032] n satisfies , The value of n rounded down; The value of n rounded up;

[0033] The power of the corresponding fuel cell stack is ; The power of the corresponding fuel cell stack is , and for:

[0034] (6)

[0035] When the power is At that time, the efficiency of fuel cells for:

[0036] (7)

[0037] When the power is At that time, the efficiency of fuel cells for:

[0038] (8)

[0039] In the formula, m represents the hydrogen consumption per unit time of the multi-stacking fuel cell system, and L represents the lower calorific value of hydrogen; (Comparison) and The size, if Then the optimal number of fuel cell stacks online at time k is n k = ;like Then the optimal number of fuel cell stacks online at time k is n k = .

[0040] Furthermore, the process of obtaining the "startup" set and the "standby" set is as follows:

[0041] The optimal number of fuel cell stacks in a multi-stack fuel cell system at time k-1 is n. k-1 The optimal number of fuel cell stacks in the multi-stack fuel cell system at time k is n. k In a multi-stack fuel cell system, the remaining stacks are in standby mode.

[0042] The net increase in the number of fuel cell stacks in the multi-stack fuel cell system from time k-1 to time k is:

[0043] (9)

[0044] In a multi-stack fuel cell system, the total number of stacks is N. If the j-th stack is online, then the startup cost of the j-th stack at time k is... for: ; is the total degradation voltage of the stacks,

[0045] If the jth stack is in standby state, the start-up cost of the jth stack at the kth moment is: ; 1≤j≤N; wherein, is the total degradation voltage of the stacks, is the switching degradation voltage of the stacks;

[0046] Divide the stacks in the multi-stack fuel cell system into online stacks and standby stacks, and sort the online stacks and the standby stacks according to the size of the total degradation voltage of each stack;

[0047] If , pick out the stack with the least total degradation voltage from the standby stacks and put it into the "start-up" set; if , pick out the stack with the most total degradation voltage from the online stacks and put it into the "standby" set; Put the remaining stacks in the online stacks and the remaining stacks in the standby stacks into the "to-be-allocated" set, and sort them according to the start-up cost of the stacks;

[0048] According to the sorted "to-be-allocated" set, if >0, pick out the stack with the least start-up cost

[0049] , put the picked stack into the "start-up" set, and put the remaining stacks in the "to-be-allocated" set into the "standby" set; if , pick out the stack with the least start-up cost , put the picked stack into the "start-up" set, and put the remaining stacks in the "to-be-allocated" set into the "standby" set; finally, the stacks in the "start-up" set are the stacks that should be started up at the kth moment.

[0050] Further, the step of calculating the power borne by each stack in the "start-up" set is:

[0051] The total number of stacks is N, the demand power at the current moment k is , the number of online stacks is n k , 1≤n k ≤N, the power borne by each stack is , the efficiency of each fuel cell is , 1≤i≤n k , and L is the low heat value of hydrogen, then the hydrogen consumption of the ith stack is:

[0052] ​​​​ (10)

[0053] The hydrogen consumption function of the multi-stack fuel cell system at time k is

[0054] (11)

[0055] The constraint condition satisfied by formula (11) is

[0056] (12)

[0057] The Lagrange function F is constructed as

[0058] (13)

[0059] The first-order partial derivative of the function is obtained as

[0060] (14)

[0061] Substituting into the expression of formula (14) has

[0062] (15)

[0063] In formula a, b are constants, is the Lagrange multiplier; formula (15) has a solution when and only when , at this time each stack works near the optimal efficiency point, and the output power of each stack is

[0064] (16)

[0065] As described above, the demand power at time k is borne by the selected stacks, each stack bears the same power, and the power of each stack is .

[0066] ​The beneficial effects of the present application are: the present application determines the number of online stacks according to the demand power at the current moment, avoids the problem of increasing the operation cost of the multi-stack fuel cell system caused by starting too many stacks in the low power interval, compared with the chain distribution strategy and the average distribution strategy, the hydrogen consumption of the multi-stack fuel cell system of the present application is reduced by 6.6% and 11.3% respectively, and the economy of the multi-stack fuel cell system is improved; the present application preferentially starts the stacks with less degradation according to the degradation difference between the stacks, and makes the stacks with more degradation into standby state, thereby delaying the voltage degradation and ensuring the consistency of the stack degradation after long time operation, avoiding the problem of inconsistent degradation or even shutdown and maintenance caused by frequent start-stop and long time operation of a single stack, improving the output capacity of the multi-stack fuel cell system, and effectively prolonging the service life of the multi-stack fuel cell system; at the same time, the present application has good balancing effect on the stacks with large degradation difference in the multi-stack fuel cell system, and the test results show that after a period of operation, the degradation between the stacks tends to be consistent again using the method of the present application; the power output device used in the present application is for the multi-stack fuel cell system, which is beneficial to reduce carbon emissions and realize efficient and sustainable development of the aviation industry, and the present application adopts the structure of multiple fuel cells in parallel, realizes fault tolerance through the redundancy of the stacks, and improves the reliability and durability of the multi-stack fuel cell system. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 The flow chart of the multi-stack fuel cell system power distribution method based on stack degradation consistency of the present application is shown in the figure;

[0068] Figure 2 The architecture diagram of the multi-stack fuel cell system of the present application is shown in the figure;

[0069] Figure 3 The efficiency curve of the fuel cell in the present application is shown in the figure;

[0070] Figure 4 The flow chart of the stack selection method in the present application is shown in the figure;

[0071] Figure 5 The aircraft demand power curve in the present application is shown in the figure;

[0072] Figure 6 The power distribution result in the present application is shown in the figure; (a) is the FC1 power curve; (b) is the FC2 power curve; (c) is the FC3 power curve; (d) is the FC4 power curve; (e) is the FC5 power curve; (f) is the FC6 power curve;

[0073] Figure 7 The stack degradation voltage growth curve in the present application is shown in the figure. DETAILED DESCRIPTION

[0074] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0075] A power allocation method for multi-stack fuel cell systems based on stack decay consistency includes the following steps:

[0076] Step 1: Construct a multi-stack fuel cell system;

[0077] The multi-stack fuel cell system comprises N fuel cells connected in parallel; each fuel cell is identical; each fuel cell includes a stack, auxiliary energy storage elements, and a boost converter; each stack is connected to a DC bus via a boost converter; the parallel structure of the multi-stack fuel cell system improves reliability and allows for independent control of each stack.

[0078] Step 2: Establish a fuel cell stack degradation model;

[0079] The fuel cell stack degradation model includes fuel cell output voltage, fuel cell aging decline voltage, fuel cell standby degradation voltage, fuel cell switching degradation voltage, and total fuel cell degradation voltage.

[0080] fuel cell output voltage for:

[0081] (1)

[0082] In the formula, For Nernst voltage, For fuel cell stack activation loss, For the ohmic loss of the fuel cell stack, This refers to the concentration loss of the fuel cell stack.

[0083] As fuel cell stacks operate for longer periods, their performance degrades. Under rated operating conditions, the voltage drop due to aging occurs... for:

[0084] (2)

[0085] In the formula The runtime is measured in hours (h). The first aging factor; The second aging factor, The value is -7.339 × 10 -6 ; The value is -1.594 × 10 -2 ;

[0086] Standby voltage of fuel cell stack in standby mode for:

[0087] (3)

[0088] wherein is the decay rate, taken as 8.662 , is the standby time;

[0089] In addition to the normal operation of the stack to produce a stack standby decay voltage, the stack each time from standby state to rated power operation state switching will also cause the voltage decay, each state conversion of the stack switching decay voltage is , = 0.4185 ;

[0090] The total decay voltage of the stack is:

[0091] (4)

[0092] wherein, is the number of state transitions;

[0093] Step three: according to the stack decay model to determine the current time demand power of the stack best online number;

[0094] The demand power at time k is P k is:

[0095] (5)

[0096] wherein P opt is the best power corresponding to the best efficiency point of the fuel cell;

[0097] n satisfies , is the value of n down; is the value of n up;

[0098] The power of the stack corresponding to the value of n down is ; The power of the stack corresponding to the value of n up is , and is:

[0099] (6)

[0100] When the power is , the efficiency of the fuel cell is is:

[0101] (7)

[0102] When the power is , the efficiency of the fuel cell is is:

[0103] (8)

[0104] In the formula, m represents the hydrogen consumption per unit time of the multi-stacking fuel cell system, and L represents the lower calorific value of hydrogen; since the efficiency curve of a fuel cell has an optimal efficiency point and an optimal output power P... opt To reduce hydrogen consumption in multi-stacking fuel cell systems, as many fuel cells as possible should operate near their optimal efficiency point; comparison and The size, if Then the optimal number of fuel cell stacks online at time k is n k = ;like Then, at time k, the optimal number of fuel cell stacks online is n. k = ;

[0105] Step 4: Based on the optimal number of fuel cell stacks online, select the appropriate stacks to obtain a "startup" set and a "standby" set. The "startup" set contains n... k The fuel cell stack is the fuel cell stack that should be started at time k;

[0106] From step three, we obtain the number of fuel cell stacks online in the multi-stack fuel cell system at time k-1 as n. k-1 The number of fuel cell stacks in the multi-stack fuel cell system currently online at time k is n. k The remaining stacks are in standby mode; the net increase in the number of fuel cell stacks in the multi-stack fuel cell system from time k-1 to time k is:

[0107] (9)

[0108] In a multi-stack fuel cell system, the total number of stacks is N. If the j-th stack is online, then the startup cost of the j-th stack at time k is... for: ;

[0109] If the j-th fuel cell stack is in standby mode, then the startup cost of the j-th fuel cell stack at time k is... for: ; 1 ≤ j ≤ N;

[0110] The steps for selecting fuel cells to obtain the "startup" set and the "standby" set are as follows:

[0111] The fuel cell stacks in the multi-stack fuel cell system are divided into online stacks and standby stacks, and then sorted in the online stacks and standby stacks according to the magnitude of the total decay voltage of each stack.

[0112] like Then, select the battery stack with the lowest total voltage decay from the standby battery stacks. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set.

[0113] If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set.

[0114] If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set. If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set.

[0115] If the number of the on-line stacks is less than the number of the stacks in the "start" set, then the stacks in the "start" set are put into the "on-line" set; if the number of the on-line stacks is more than the number of the stacks in the "start" set, then the stacks in the "on-line" set are put into the "start" set.

[0116] Step five: according to the optimal number of the on-line stacks and the stacks in the "start" set, calculate the power of each stack in the "start" set.

[0117] The step of calculating the power of each stack in the "start" set is:

[0118] The sum of the power of the stacks must meet the demand power at the current time, under the premise of the same parameters and aging state, the optimal power output under the demand power is solved by Lagrange multiplier method.

[0119] The total number of the stacks is N, the demand power at the current time k is P(k), the number of the on-line stacks is n(k), 1≤n(k)≤N, the power of each stack is P(k,i), 1≤i≤n(k), the efficiency of each fuel cell is η, 1≤i≤n(k), L is the low heat value of hydrogen, then the hydrogen consumption of the i-th stack is: k k k

[0120] (10)

[0121] The hydrogen consumption function of the multi-stack fuel cell system at k time​​​​​​​ is:

[0122] (11)

[0123] The constraint condition satisfied by formula (11) is:

[0124] (12)

[0125] The Lagrange function F is constructed as:

[0126] (13)

[0127] The first-order partial derivative of the function is obtained:

[0128] (14)

[0129] Since the hydrogen consumption function is consistent with the first-order derivative, substitute it into the expression of , which is converted to:

[0130] (15)

[0131] In formula (15), a and b are constants, is the Lagrange multiplier; formula (15) has a solution when and only when , at this time, each stack works near the optimal efficiency point, and the output power is:

[0132] (16)

[0133] As described above, the demand power at time k is borne by the selected stacks, and each stack bears the same power, and the power of each stack is .

[0134] In an embodiment of the present application, a multi-stack fuel cell system composed of six fuel cells with a maximum power of 100 kW and an optimal output power of 34 kW provides power for the load, Figure 5 is the load power demand, the total duration is 1710s; Figure 6 is the power allocation result; Figure 7 is the recession voltage growth curve of the six stacks. From Figure 6It can be seen that the stack works near the best efficiency point, and the rest of the time is in standby state. For example, in the period of 744~779s, the demand power is above 180kW, FC3, FC4 are started first because of the least degradation, until 6 stacks are all online and work near the best efficiency point; then in the period of 780~870s, the fuel cell power continues to decrease until below 70kW, the number of online stacks is reduced, FC5 is put into standby state first because of the most degradation, then FC6, FC1, FC2, finally FC3 and FC4 continue to work. It can be seen that the degradation voltage of 6 stacks basically keeps consistent growth. Figure 7 It can be seen that the degradation voltage of 6 stacks basically keeps consistent growth. The effect of the power distribution method of the application compared with chain distribution and average distribution is shown in Table 1, it can be seen that the hydrogen consumption is reduced by 6.6%, 11.3% respectively, effectively improving the fuel economy of the system; the variance of the voltage degradation of the power distribution method of the application compared with chain distribution is reduced by 97.7%, compared with average distribution, the voltage degradation of the stack is reduced by 43.8%, which shows that the distribution method of the application delays the voltage degradation while keeping the consistency of the degradation, effectively prolonging the service life of the system.

[0135] Table 1 Voltage degradation and system hydrogen consumption of the power distribution method of the application compared with traditional distribution methods

[0136]

Claims

1. A method for power distribution in a multi-stack fuel cell system based on stack degradation consistency, characterized by, The method comprises the following steps: Step 1: constructing a multi-stack fuel cell system; The multi-stack fuel cell system includes N a plurality of fuel cells connected in parallel; wherein each fuel cell is identical; each fuel cell includes a stack, an auxiliary energy storage element, and a boost converter; each stack is connected to a DC bus through a boost converter; Step 2: establishing a stack degradation model based on the multi-stack fuel cell system; The stack degradation model comprises a stack output voltage, a stack aging drop voltage, a stack standby degradation voltage, a stack switching degradation voltage and a stack total degradation voltage; Step 3: determining the optimal number of stacks online according to the demand power at the current time; Step four: according to the optimal number of stacks online, select the stacks in the multi-stack fuel cell system to obtain a "start" set and a "standby" set, the stacks in the "start" set n k The standby stacks are the stacks that should be started at any time k ​ k The optimal number of stacks online in the multi-stack fuel cell system at time t is n k-1 ; the current k The optimal number of stacks online in the multi-stack fuel cell system at time t is n k The remaining stacks in the multi-stack fuel cell system are in standby state; k -1 time to k The net number of stacks added to the multi-stack fuel cell system at time is: (9) The total number of stacks in the multi-stack fuel cell system is N， The first j The first j The start-up cost of the first k stack at the time instant t is ; wherein is the total degradation voltage of the stacks; and is the degradation voltage of the first stack. If the first j If the TECH stack is in standby mode, then the first... j Taipower stacked in k Startup cost at any time for: Where 1≤ j ≤ N ;in, This is the total decay voltage of the fuel cell stack. Switching the decay voltage of the fuel cell stack; Step 5: calculating the power borne by each stack in the "start" set according to the optimal number of stacks online and the stacks in the "start" set.

2. The method of claim 1, wherein, The stack output voltage is: (1) wherein is the Nernst voltage, is the activation loss of the stack, is the ohmic loss of the stack, is the concentration difference loss of the stack; The stack degradation down voltage Is: (2) wherein is the run time, the unit of the run time is h, is the first aging coefficient; is the second aging coefficient, has a value of -7.339 x 10 -6 ; has a value of -1.594 x 10 -2 ; The stack standby decay voltage Is: (3) In the formula is the decay rate, which has a value of 8.662 , is the standby time; The stack switching decay voltage is , = 0.4185 ; The total stack decay voltage is: (4) wherein, is the number of state transitions.

3. The method of claim 1, wherein, The process of determining the optimal number of stacks online is: k the power demand at the time , the power demand at the time is calculated k the ratio of the power demand at the time to the optimum power corresponding to the optimum efficiency point of the fuel cell n : (5) wherein Poptis the optimal power corresponding to the optimal efficiency point of the fuel cell; n satisfies , is the value of n rounded down; is the value of n rounded up; The power of the corresponding stack is ; The power of the corresponding stack is , and is: (6) When the power of the stack is the efficiency of the fuel cell is : (7) When the power of the stack is the efficiency of the fuel cell is : (8) wherein m is the hydrogen consumption of the multi-stack fuel cell system per unit time, L is the lower heating value of hydrogen; compare with the size of, if then k the optimal number of stacks online at the moment n k = if then k the optimal number of stacks online at the moment n k = .

4. The method of claim 1, wherein, The process of obtaining the "start" set and the "standby" set further comprises: The stacks in the multi-stack fuel cell system are divided into online stacks and standby stacks, and each stack in the online stacks and the standby stacks is sorted according to the size of the stack total degradation voltage of each stack; like Then, select the battery stack with the lowest total voltage decay from the standby battery stacks. The platform is placed in the "Startup" set; if Then, select the fuel cell stack with the highest total voltage decay from the online fuel cell stacks. The station is placed in the "standby" collection; putting the remaining stacks in the online stacks and the remaining stacks in the standby stacks into a "to be allocated" collection and sorting the stacks by their start-up cost performing the sorting; According to the sorted "to be assigned" set, if > 0, the power station with the minimum start cost is selected , the selected power station is put into the "start" set, and the remaining power stations in the "to be assigned" set are put into the "standby" set; if , the power station with the minimum start cost is selected , the selected power station is put into the "start" set, and the remaining power stations in the "to be assigned" set are put into the "standby" set; finally, the power stations in the "start" set are the power stations that should be started at the moment. k ​​ 5. The method of claim 1, wherein, The step of calculating the power borne by each stack in the "start" set is: The total number of stacks is N , the demand power is k , the number of stacks online is , the number of stacks online is n k , 1≤ n k ≤ N , the power borne by each stack is , the efficiency of each fuel cell is , 1≤ i ≤ n k , L , the low heat value of hydrogen is, and the hydrogen consumption of the first i stack is : (10) A multi-stack fuel cell system is provided k The hydrogen consumption function at time t is H(t) = (11) The constraint condition satisfied by formula (11) is: (12) Constructing the Lagrangian function F is: (13) The first-order partial derivative of the Lagrange function is obtained as: (14) Will Substituting into the expression of equation (14) yields: (15) wherein a , b are constants, is the Lagrange multiplier; equation (15) has a solution if and only if when each stack operates near its optimal efficiency point, and the output power of each stack is (16) In summary, the demand power at time k is determined by the selected The power of each stack is the same, and the power of each stack is . 6.A terminal device, comprising a processor, a memory, and a computer program stored in the memory; characterized in that, When the processor executes the computer program, the method for power distribution of the multi-stack fuel cell system based on stack degradation consistency according to any one of claims 1-5 is realized.

7. A computer readable storage medium having stored therein a computer program; characterized in that, When the computer program is executed by the processor, the method for power distribution of the multi-stack fuel cell system based on stack degradation consistency according to any one of claims 1-5 is realized.

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