Stack and fuel cell system each having multi-stage cascade structure

Abstract

Disclosed in the present application are a stack and a fuel cell system each having a multi-stage cascade structure. The stack comprises multi-stage series-connected cell arrays, a first fuel flow path and a second fuel flow path, each stage of cell array comprising a plurality of single cells connected in parallel, all stages of cell arrays being communicated by means of the first fuel flow path, and the single cells in the same stage of cell array being communicated by means of the second fuel flow path. The number of single cells in each stage of cell array and an array fuel utilization rate corresponding to each stage of cell array satisfy a first single cell quantity constraint condition, and the number of single cells in the front and rear stages of cell arrays and the cell fuel utilization rate corresponding to each single cell in the front and rear stages of cell arrays satisfy a second single cell quantity constraint condition, such that the equivalent hydrogen amount of fuel consumed by each single cell per unit time is equal, and the output current of each single cell is equal. The present application can realize fuel recycling, improve the fuel utilization rate and power generation efficiency, and can be widely applied to the field of fuel cells.

Description

A multi-stage connection structure of a stack and a fuel cell system TECHNICAL FIELD

[0001] The present application relates to the field of fuel cells, and in particular to a multi-stage connection structure of a stack and a fuel cell system. BACKGROUND

[0002] A fuel cell is an electrochemical device that can directly convert chemical energy stored in fuel and oxidant into electrical energy. A fuel cell is usually configured as a single cell and stacked in a stacked manner to form a stack; one or more stacks form a fuel cell system together with a fuel gas management module, a water treatment module, a power management module, and a master control module.

[0003] In order to improve the power generation, power generation efficiency, and fuel utilization rate of the fuel cell system and the stack, multiple stacks or multiple single cells are usually designed in series and parallel. However, in the current design of the fuel cell system and the stack, there is a risk of imbalance in the number of stacks and single cells, which reduces the overall fuel utilization rate of the fuel cell system and the stack. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a multi-stage connection structure of a stack and a fuel cell system with high fuel utilization rate.

[0005] To achieve the above purpose, one aspect of an embodiment of the present application provides a multi-stage connection structure of a stack, comprising a plurality of battery arrays connected in series, a first fuel flow path, and a second fuel flow path. Each battery array comprises a plurality of single cells connected in parallel. Each battery array is connected through the first fuel flow path. The single cells in the same battery array are connected through the second fuel flow path. The number of single cells in each battery array and the array fuel utilization rate corresponding to each battery array satisfy a first single cell number constraint condition. The number of single cells in the front and rear battery arrays and the cell fuel utilization rate corresponding to each single cell in the front and rear battery arrays satisfy a second single cell number constraint condition, so that the equal hydrogen amount of consumed fuel of each single cell per unit time is equal and the output current of each single cell is equal.

[0006] In some embodiments, the number of single cells in each battery array and the array fuel utilization rate corresponding to each battery array satisfy the first single cell number constraint condition. The first single cell number constraint condition is:

[0007] wherein N x represents the number of single cells in the C x th battery array, N1 represents the number of single cells in the C1 iIndicates the Cth i The fuel utilization rate of the battery array corresponding to the level, η x Indicates the Cth x The array fuel utilization rate corresponding to the battery array of the C1th stage, where η1 represents the array fuel utilization rate corresponding to the battery array of the C1th stage, and i and x are both positive integers and i∈[1, x-1].

[0008] In some embodiments, the number of individual cells in the preceding and following battery arrays and the battery fuel utilization rate corresponding to each individual cell in the preceding and following battery arrays satisfy a second single-cell number constraint condition, which is:

[0009] Where, N x Indicates the Cth x The number of individual cells in the battery array described in the stage, N x-1 Indicates the Cth x-1 The number of individual cells in the battery array described above, γ i Indicates the Cth x-1 The battery fuel utilization rate, β, corresponding to the i-th single cell in the battery array. i Indicates the Cth x The battery fuel utilization rate corresponding to the i-th single cell in the battery array, where i and x are both positive integers and i∈[1, N]. x-1 ].

[0010] In some embodiments, the fuel utilization rate of the fuel cell stack and the array fuel utilization rate of each stage of the battery array satisfy a fuel utilization rate constraint condition, which is:

[0011] Where, η 堆 N represents the fuel utilization rate of the fuel cell stack. i Indicates the Cth i The number of individual cells in the battery array described above, η i Indicates the Cth i The battery array corresponding to the stage is the array fuel utilization rate, where i and x are both positive integers and i∈[1, x].

[0012] In some embodiments, the fuel utilization rate of the fuel cell stack satisfies 60% ≤ η 堆 ≤99% or 70% ≤η 堆 ≤95%, the array fuel utilization rate corresponding to each level of the battery array satisfies 30%≤η x ≤75% or 50% ≤η x ≤75%, where η x Indicates the Cth xwherein x is a positive integer.

[0013] In some embodiments, the number of single cells in each stage of the battery array satisfies a third single cell number constraint, which is:

[0014] When the stack comprises a first stage battery array and a second stage battery array connected in series, the number of single cells in the first stage battery array and the number of single cells in the second stage battery array satisfy one of N1:N2 is 2:1, 3:1, 42:13, 39:12 or 4:1, wherein N1 represents the number of single cells in the first stage battery array and N2 represents the number of single cells in the second stage battery array.

[0015] When the stack comprises a first stage battery array, a second stage battery array and a third stage battery array connected in series, the number of single cells in the first stage battery array, the number of single cells in the second stage battery array and the number of single cells in the third stage battery array satisfy one of N1:N2:N3 is 9:3:1, 39:12:4 or 42:13:4, wherein N1 represents the number of single cells in the first stage battery array, N2 represents the number of single cells in the second stage battery array and N3 represents the number of single cells in the third stage battery array.

[0016] To achieve the above object, another aspect of the embodiments of the present application proposes a multi-stage fuel cell system with a cascade structure, comprising a plurality of stack groups connected in series, a third fuel flow path and a fourth fuel flow path, each of the stack groups comprises a plurality of stacks connected in parallel, the stacks in each of the stack groups are connected through the third fuel flow path, and the stacks in the same stack group are connected through the fourth fuel flow path, wherein the number of stacks in each of the stack groups and the stack group fuel utilization rate corresponding to each of the stack groups satisfy a first stack number constraint, and the number of stacks in the front and rear stack groups and the stack fuel utilization rate corresponding to each of the stacks in the front and rear stack groups satisfy a second stack number constraint, so that the equivalent hydrogen amount of the consumed fuel of each of the stacks per unit time is equal and the output current of each of the stacks is equal.

[0017] In some embodiments, the number of stacks in each of the stack groups and the stack group fuel utilization rate corresponding to each of the stack groups satisfy the first stack number constraint, which is:

[0018] wherein M y represents the number of stacks in the D y th stack group, M1 represents the number of stacks in the D1th stack group, and μ j represents the number of stacks in the Dj the fuel utilization of the stack group corresponding to the Dth stack group, μ y the fuel utilization of the stack group corresponding to the Dth stack group, μ y the fuel utilization of the stack group corresponding to the Dth stack group, μ

[0019] In some embodiments, the number of stacks in the front and rear stack groups and the fuel utilization of each stack in the front and rear stack groups satisfy the second stack number constraint condition, the second stack number constraint condition being:

[0020] wherein M y the number of stacks in the Dth stack group, M y the number of stacks in the Dth stack group, δ y-1 the number of stacks in the Dth stack group, δ y-1 the fuel utilization of the jth stack in the Dth stack group, ξ j the fuel utilization of the jth stack in the Dth stack group, ξ y-1 the fuel utilization of the jth stack in the Dth stack group, ξ j the fuel utilization of the jth stack in the Dth stack group, ξ y the fuel utilization of the jth stack in the Dth stack group, ξ y-1 wherein j and y are positive integers and j ∈ [1, M 总 ].

[0021] In some embodiments, the system fuel utilization of the fuel cell system and the fuel utilization of each stack group satisfy the system fuel utilization constraint condition, the system fuel utilization constraint condition being:

[0022] wherein μ 总 represents the system fuel utilization, M j the number of stacks in the Dth stack group, μ j the fuel utilization of the stack group corresponding to the Dth stack group, μ j the fuel utilization of the stack group corresponding to the Dth stack group, μ j wherein j and y are positive integers and j ∈ [1, y].

[0023] In some embodiments, the system fuel utilization satisfies 60% ≤ μ 总 ≤ 99% or 70% ≤ μ 总 ≤ 95%, and the fuel utilization of each stack group satisfies 30% ≤ μ y ≤ 75% or 50% ≤ μ y ≤ 75%, wherein μ y represents the system fuel utilization. yThe fuel utilization rate of the fuel cell system is y times the fuel utilization rate of the fuel cell stack group corresponding to the fuel cell stack group, and y is a positive integer.

[0024] In some embodiments, the number of fuel cells in each stage of the fuel cell stack group satisfies a third fuel cell number constraint condition, which is:

[0025] When the fuel cell system comprises a first stage fuel cell stack group and a second stage fuel cell stack group in series, the number of fuel cells in the first stage fuel cell stack group and the number of fuel cells in the second stage fuel cell stack group satisfy one of M1:M2 is 2:1, 3:1, 42:13, 39:12 or 4:1, wherein M1 represents the number of fuel cells in the first stage fuel cell stack group, and M2 represents the number of fuel cells in the second stage fuel cell stack group.

[0026] When the fuel cell system comprises a first stage fuel cell stack group, a second stage fuel cell stack group and a third stage fuel cell stack group in series, the number of fuel cells in the first stage fuel cell stack group, the number of fuel cells in the second stage fuel cell stack group and the number of fuel cells in the third stage fuel cell stack group satisfy one of M1:M2:M3 is 9:3:1, 39:12:4 or 42:13:4, wherein M1 represents the number of fuel cells in the fuel cell stack group, M2 represents the number of fuel cells in the second stage fuel cell stack group, and M3 represents the number of fuel cells in the third stage fuel cell stack group.

[0027] The beneficial effects of the present application are: the fuel cell stack of the multi-stage series structure provided by the present application can realize the recycling of fuel, improve the fuel utilization rate and the power generation efficiency by connecting the second fuel flow paths of multiple single cells in parallel to form a cell array and connecting the first fuel flow paths of multiple cell arrays in series to form a fuel cell stack, so that the fuel exhaust of the upper stage flows into the lower stage for reaction; in addition, the number of single cells is limited by the number constraint condition of single cells to make the equal hydrogen consumption and the equal output current of each single cell in the fuel cell stack in unit time, which can reduce the risk of over-utilization of single cells, effectively improve the fuel utilization rate and the power generation efficiency, and improve the stability and reliability of the operation of the fuel cell stack.

[0028] The fuel cell system of the multi-stage series structure provided by the present application can realize the recycling of fuel, improve the fuel utilization rate and the power generation efficiency by connecting the fourth fuel flow paths of multiple fuel cell stacks in parallel to form a fuel cell stack group and connecting the third fuel flow paths of multiple fuel cell stack groups in series to form a fuel cell system, so that the fuel exhaust of the upper stage flows into the lower stage for reaction; in addition, the number of fuel cell stacks is limited by the number constraint condition of fuel cell stacks to make the equal hydrogen consumption and the equal output current of each fuel cell stack in the fuel cell system in unit time, which can reduce the risk of over-utilization of fuel cell stacks, effectively improve the fuel utilization rate and the power generation efficiency, and improve the stability and reliability of the operation of the system. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following introduces the drawings needed to be used in the embodiments of the present application. It should be understood that the drawings introduced in the following merely for the convenience of clearly describing some embodiments of the technical solutions in the present application, and for those skilled in the art, other drawings can also be obtained without paying creative labor.

[0030] Fig. 1 is a structural schematic diagram of a multi-level structure of a fuel cell stack provided by the embodiments of the present application;

[0031] Fig. 2 is a structural schematic diagram of a multi-level structure of a fuel cell system provided by the embodiments of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application more clear, the following further describes the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein merely serve to explain the present application, and do not limit the present application. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the embodiments of the present application, but are merely examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the appended claims.

[0033] It can be understood that the terms "first", "second", and the like used in the present application can be used herein to describe various concepts, but unless specifically stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon" or "in response to determining".

[0034] The terms "at least one", "multiple", "each", "any", and the like used in the present application include one, two or more than two, multiple includes two or more than two, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0035] A fuel cell is an electrochemical device that can directly convert chemical energy stored in fuel and oxidant into electrical energy. A fuel cell is usually used as a single cell and stacked in a stacked manner to form a fuel cell stack; one or more fuel cell stacks and modules such as a fuel gas management module, a water treatment module, a power management module, and a master control module form a fuel cell system.

[0036] In order to improve the power generation, power generation efficiency and fuel utilization rate of the fuel cell system and the stack, multiple stacks or multiple single cells are usually designed in series and parallel. However, in the current design of the fuel cell system and the stack, the number of stacks and single cells is often not properly matched, which reduces the overall fuel utilization rate of the fuel cell system and the stack.

[0037] Therefore, the embodiment of the present application provides a multi-stage cascade structure stack. A plurality of single cells are connected in parallel to form a cell array, and the first fuel flow paths of multiple cell arrays are connected in series to form a stack, so that the fuel exhaust of the upper stage flows into the lower stage for reaction, thereby realizing the recycling of fuel and improving the fuel utilization rate and power generation efficiency. In addition, the number of single cells is limited by the number constraint condition, so that the equivalent hydrogen amount of the consumed fuel of each single cell in the stack per unit time is equal and the output current is equal, thereby reducing the risk of over-utilization of single cells, improving the fuel utilization rate and power generation efficiency, and improving the stability and reliability of the stack operation.

[0038] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a multi-stage cascade structure stack provided by the embodiment of the present application. The embodiment of the present application provides a multi-stage cascade structure stack, which comprises a plurality of multi-stage connected cell arrays, a first fuel flow path and a second fuel flow path. Each cell array comprises a plurality of parallel single cells. The cell arrays are connected by the first fuel flow path. The single cells in the same cell array are connected by the second fuel flow path. The number of single cells in each cell array and the array fuel utilization rate corresponding to each cell array satisfy a first single cell number constraint condition. The number of single cells in the front and rear cell arrays and the cell fuel utilization rate corresponding to each single cell in the front and rear cell arrays satisfy a second single cell number constraint condition, so that the equivalent hydrogen amount of the consumed fuel of each single cell per unit time is equal and the output current of each single cell is equal.

[0039] It should be noted that the equivalent hydrogen amount A0 is equal, which means that the amount of substance of the equivalent hydrogen converted from the consumed fuel of each single cell per unit time is equal. The arithmetic mean of the equivalent hydrogen amount of the consumed fuel of each single cell is A. If the difference between a certain single cell and A is within ±5%, it can also be considered that the equivalent hydrogen amount of the consumed fuel of the single cell is equal to the equivalent hydrogen amount A0 of the consumed fuel of each single cell.

[0040] The output current I0 of each single cell is equal, and any multiple single cells can output the generated current in series. The arithmetic mean of the current generated by each single cell is I. If the current generated by a certain single cell is within ±5% of I, it can also be considered that the current of the single cell is equal to the current I0 of each single cell. The embodiment of the present application makes the current generated by each single cell equal, so that the same pull load device can be used to pull the output current, thereby reducing the auxiliary equipment of the stack and reducing the cost.

[0041] For example, the fuel cell stack in this application embodiment includes C1, C2 to C3. x The battery array consists of multiple levels, with the number of individual cells in each level ranging from N1 to N2. x And N1>N2>...>N x N1, N2 to N x All are positive integers, and x≥2.

[0042] The fuel gas is input into each stage of the battery array in series, and then input into each individual cell of the battery array in parallel within each stage. This allows the remaining fuel gas from the reaction in the previous stage to flow into the next stage of the battery array to participate in the reaction. Specifically, the fuel gas in adjacent battery arrays C... x-1 and C x Fuel communication is achieved between them through the first fuel flow path, C x-1 The fuel outlets of each individual cell in the battery array are connected to the first fuel flow path via fuel exhaust branch pipes, thereby allowing the fuel exhaust from each individual cell in the previous stage battery array to converge in the first fuel flow path; C x The fuel inlet of each cell in the battery array is connected to the first fuel flow path through a fuel intake branch pipe, thereby diverting the fuel in the first fuel flow path to each cell in the next battery array.

[0043] As a further optional implementation, the number of individual cells in each stage of the battery array and the array fuel utilization rate corresponding to each stage of the battery array satisfy a first single cell number constraint condition, which is:

[0044] Where, N x Indicates the Cth x The number of individual cells in the C1-th stage battery array, N1 represents the number of individual cells in the C1-th stage battery array, η i Indicates the Cth i The array fuel utilization rate corresponding to the C-th stage battery array, ηx represents the C-th stage. x The array fuel utilization rate corresponding to the C1th stage battery array, η1 represents the array fuel utilization rate corresponding to the C1th stage battery array, i and x are both positive integers and i∈[1, x-1].

[0045] Specifically, let C1, C2 to C x The array gas utilization rates corresponding to the multi-stage battery arrays are η1, η2 to η x Then the Cth x The number of individual cells N in a multi-stage battery array x Satisfy the following formula:

[0046] Based on the above formula, we can further obtain the Cth...x Number of single cells N of a battery array at a level x satisfies the following formula (i.e., a first single cell number constraint condition):

[0047] It should be noted that, by designing the array fuel utilization rates of the battery arrays at different levels to meet the first single cell number constraint condition, the application embodiments can make the fuel consumption of each single cell per unit time equal to A0, and the output current of each single cell equal, in the normal operation of the stack, without the need for individual control of the output current of each single cell.

[0048] Further as an optional implementation, the number of single cells in the front and rear battery arrays and the battery fuel utilization rates corresponding to the single cells in the front and rear battery arrays satisfy a second single cell number constraint condition, and the second single cell number constraint condition is:

[0049] wherein, N x represents the number of single cells in the C x battery array, N x-1 represents the number of single cells in the C x-1 battery array, γ i represents the battery fuel utilization rate corresponding to the i-th single cell in the C x-1 battery array, β i represents the battery fuel utilization rate corresponding to the i-th single cell in the C x battery array, i and x are positive integers and i∈[1, N x-1 ].

[0050] Specifically, assuming that the C x-1 battery array has N x-1 single cells, and the fuel utilization rates corresponding to each single cell are γ1, γ2,..., γ (Nx-1) , the C x battery array has N x single cells, and N x-1 >N x , and the battery fuel utilization rates corresponding to each single cell are β1, β2,..., β (Nx) , then N x-1 satisfies the following formula (i.e., the second single cell number constraint condition):

[0051] It should be noted that, in this embodiment of the application, by designing the number of single cells in two adjacent battery arrays and the fuel utilization rate of each single cell in the two adjacent battery arrays to meet the requirements of the second single cell number constraint, the stack can automatically achieve the same amount of hydrogen A0 consumed by each single cell per unit time during normal operation, and achieve the same current output by each single cell, without the need for separate control of the output current for each single cell.

[0052] As a further optional implementation, the fuel utilization rate of the fuel cell stack and the array fuel utilization rate of each stage of the battery array satisfy the fuel utilization rate constraint condition, which is:

[0053] Where, η 堆 N represents the fuel utilization rate of the fuel cell stack. i Indicates the Cth i The number of individual cells in a multi-stage battery array, η i Indicates the Cth i The array fuel utilization rate corresponding to the battery array, where i and x are both positive integers and i∈[1, x].

[0054] Specifically, the fuel utilization rate of the fuel cell stack is η. 堆 C1, C2 to C x The array gas utilization rates corresponding to the multi-stage battery arrays are η1, η2 to η x Then the fuel utilization rate η of the fuel cell stack 堆 The following formula (i.e., the fuel utilization constraint of the fuel cell stack) must be satisfied:

[0055] It should be noted that when the fuel utilization rate of the fuel cell stack and the array fuel utilization rate of each level of the battery array meet the above-mentioned fuel utilization rate constraints, it can be ensured that the individual cells of each level of the battery array will not be overloaded, the life of the individual cells will be improved, and the overall fuel cell stack will maintain a high utilization rate.

[0056] As an optional implementation, the fuel utilization rate of the fuel cell stack satisfies 60% ≤ η. 堆 ≤99% or 70% ≤η 堆 ≤95%, the array fuel utilization rate corresponding to each level of battery array meets 30%≤η x ≤75% or 50% ≤η x ≤75%, where η x Indicates the Cth x The array fuel utilization rate corresponding to the battery array, where x is a positive integer.

[0057] Specifically, the fuel utilization rate of the fuel cell stack is set to satisfy 60% ≤ η. 堆≤ 99% or 70% ≤ η 堆 ≤ 95% to maximize fuel utilization within the range in which the stack can be operated stably, reduce fuel consumption cost; set the array fuel utilization rate corresponding to each stage battery array to satisfy 30% ≤ η x ≤ 75% or 50% ≤ η x ≤ 75% to optimize the fuel utilization rate distribution of each stage battery array, improve the overall fuel utilization rate and performance of the entire stack.

[0058] Those skilled in the art can understand that the defined range of the stack fuel utilization rate and the array fuel utilization rate corresponding to each stage battery array can also be selected according to actual needs.

[0059] Further, as an optional implementation, the number of single cells in each stage battery array satisfies a third single cell number constraint condition, and the third single cell number constraint condition is:

[0060] When the stack contains a first stage battery array and a second stage battery array in series, the number of single cells in the first stage battery array and the number of single cells in the second stage battery array satisfy one of N1:N2 is 2:1, 3:1, 42:13, 39:12 or 4:1, wherein N1 represents the number of single cells in the first stage battery array, and N2 represents the number of single cells in the second stage battery array.

[0061] When the stack contains a first stage battery array, a second stage battery array and a third stage battery array in series, the number of single cells in the first stage battery array, the number of single cells in the second stage battery array and the number of single cells in the third stage battery array satisfy one of N1:N2:N3 is 9:3:1, 39:12:4 or 42:13:4, wherein N1 represents the number of single cells in the first stage battery array, N2 represents the number of single cells in the second stage battery array, and N3 represents the number of single cells in the third stage battery array.

[0062] Optionally, the stack in the embodiments of the present application further comprises a fuel supplement flow path, which is arranged on the first fuel flow path between two adjacent stage battery arrays. When the last stage battery array discharges residual fuel that cannot meet the requirement of "the equal hydrogen amount A0 of consumed fuel per unit time per stack" in the next stage battery array due to fluctuations or failures in the operation of the stack, the fuel supplement flow path can supplement the discharge fuel flow to the next stage battery array.

[0063] Specifically, assuming that two adjacent stage battery arrays are C x-1 and C x , whether C x needs to be supplemented can be determined by the following formula. When the following formula is satisfied, the fuel cell system controls C x-1 and Cx The fuel supplement flow path between the two-stage battery arrays is supplied with a supplement fuel, which is mixed with the remaining fuel discharged from the C x-1 th battery array and flows into the C x th battery array:

[0064] wherein η x-1 represents the array fuel utilization ratio corresponding to the C x-1 th battery array, and η x represents the array fuel utilization ratio corresponding to the C x th battery array.

[0065] Further, let the array fuel utilization ratios corresponding to the C1, C2 to C x x multi-stage battery arrays be η1, η2 to η x x respectively, then the number of single batteries N x of the C x th battery array satisfies the following formula:

[0066] wherein Q x-1 represents the equivalent hydrogen amount of the supplement fuel supplied between the adjacent C x-1 and C x arrays per unit time. When x≥3, the above formula is transformed, then the number of single batteries N x of the C x th battery array satisfies the following formula:

[0067] wherein Q i represents the equivalent hydrogen amount of the supplement fuel supplied between the adjacent C i and C i+1 arrays per unit time, i and k are positive integers, and i∈[1, x-1], k∈[2, x-1].

[0068] When x=2, the x=2 is substituted into the above formula, then the number of single batteries N2 of the C2 battery array satisfies the following formula:

[0069] wherein Q1 represents the equivalent hydrogen amount of the supplement fuel supplied between the adjacent C1 and C2 battery arrays per unit time.

[0070] It should be noted that when the fuel cell stack needs to be refueled, by designing the number of individual cells in two adjacent battery arrays, the array fuel utilization rate of two adjacent battery arrays, and the amount of hydrogen required to be refueled between two adjacent stages to meet the requirements of the above formula, the fuel cell stack can automatically achieve the same amount of hydrogen A0 consumed by each individual cell per unit time during abnormal operation, without the need for separate control of the output current for each fuel cell stack.

[0071] Furthermore, the equivalent hydrogen quantity Q of the supplementary fuel i It satisfies the following formula (selected as the best):

[0072] Furthermore, let the Cth... x-1 A battery array with N x-1 Each cell has a fuel utilization rate of γ1, γ2 to γ3, respectively. (Nx-1) , C x A battery array with N x Each cell has a fuel utilization rate of β1, β2 to β... (Nx) Then the Cth x The number of individual cells N in a multi-stage battery array x Satisfy the following formula:

[0073] It should be noted that when the system needs to be refueled, by designing the number of individual cells in two adjacent battery arrays, the fuel utilization rate of each individual cell in two adjacent battery arrays, and the amount of hydrogen required to be refueled between two adjacent stages to meet the requirements of the above formula, the fuel stack can automatically achieve the same amount of hydrogen A0 consumed by each individual cell per unit time during abnormal operation, and achieve the same current output by each fuel stack under normal operating conditions, without the need for separate control of the output current for each fuel stack.

[0074] The above describes the fuel cell stack according to the embodiments of this application. It can be understood that, compared to fuel cell stacks in the prior art, this application forms a fuel cell array by connecting the second fuel flow paths of multiple individual cells in parallel, and a fuel cell stack by connecting the first fuel flow paths of the multi-stage fuel cell array in series. This allows the fuel exhaust from the previous stage to flow into the next stage for reaction, enabling fuel recycling and improving fuel utilization and power generation efficiency. Furthermore, by ensuring that the amount of hydrogen consumed by each individual cell per unit time is equal and the output current is equal, the risk of over-utilization of individual cells can be reduced, effectively improving fuel utilization and power generation efficiency while enhancing the stability and reliability of fuel cell stack operation.

[0075] The embodiment of the present application also provides a fuel cell system with a multi-stage connection structure, a plurality of fourth fuel flow paths of a plurality of stacks are connected in parallel to form a stack group, and the third fuel flow paths of a plurality of stack groups are connected in series to form the fuel cell system, so that fuel exhaust of an upper stage flows into a lower stage to react, and the fuel can be recycled, the fuel utilization rate and the power generation efficiency are improved; in addition, the number of stacks is limited by the number constraint condition, so that the equivalent hydrogen amount of fuel consumed by each stack in the fuel cell system in a unit time is equal, and the output current is equal, the risk of over-utilization of the stack can be reduced, and the fuel utilization rate and the power generation efficiency are effectively improved, and the stability and reliability of system operation are improved.

[0076] Referring to FIG. 2, FIG. 2 is a structural schematic diagram of a fuel cell system with a multi-stage connection structure provided by the embodiment of the present application, the embodiment of the present application provides a fuel cell system with a multi-stage connection structure, which comprises a plurality of stack groups connected in series, a third fuel flow path and a fourth fuel flow path, each stack group comprises a plurality of stacks connected in parallel, the stack groups are connected through the third fuel flow path, and the stacks in the same stack group are connected through the fourth fuel flow path, wherein the number of stacks in each stack group and the stack group fuel utilization rate corresponding to each stack group satisfy a first stack number constraint condition, and the number of stacks in the front and rear stack groups and the stack fuel utilization rate corresponding to each stack in the front and rear stack groups satisfy a second stack number constraint condition, so that the equivalent hydrogen amount of fuel consumed by each stack in a unit time is equal, and the output current of each stack is equal.

[0077] It should be noted that the equivalent hydrogen amount A0 is equal, which means that the amount of substance of equivalent hydrogen converted from the fuel consumed by each stack in a unit time is equal. In addition, the arithmetic mean of the equivalent hydrogen amount of fuel consumed by each stack is A, and if the difference between a certain stack and A is within ±5 %, it can also be considered that the equivalent hydrogen amount of fuel of the stack is equal to that of each stack A0.

[0078] The output current I0 of each stack is equal, and any plurality of stacks can output generated current in a series form. The arithmetic mean of the current generated by each stack is I, and if the current generated by a certain stack is within ±5 % of I, it can also be considered that the current of the stack is equal to that of each stack I0. The embodiment of the present application makes the current generated by each stack equal, so that the same pull load device can be used to pull the output current, the auxiliary equipment of the fuel cell system is reduced, and the cost is reduced.

[0079] Exemplarily, the fuel cell system of the embodiment of the present application comprises D1, D2 to D y A plurality of stack groups, the number of stacks in each stack group is M1, M2 to M y , and M1>M2>...>M y M1, M2 to M yare positive integers, and y≥2.

[0080] The fuel gas is input into each stage of the stack group in series, and is input into each stack of the stack group in parallel in each stage of the stack group, so that the fuel gas remaining after reaction of the upper stage of the stack group flows into the lower stage of the stack group to participate in the reaction. Among them, fuel communication is realized between the adjacent two stages of the stack group D y-1 and D y through the third fuel flow path, the fuel outlets of each stack in the D y-1 stage of the stack group are communicated with the third fuel flow path through the fuel exhaust branch pipe, so that the fuel exhaust of each stack of the upper stage of the stack group converges in the third fuel flow path; and the fuel inlets of each stack in the D y stage of the stack group are communicated with the third fuel flow path through the fuel inlet branch pipe, so that the fuel in the third fuel flow path is branched to each stack of the lower stage of the stack group.

[0081] It should be emphasized that the person skilled in the art can understand that the stacks in the stack group can be stacks with a multi-stage cascade structure as mentioned above, or can be ordinary stacks without a multi-stage cascade structure, for example, a battery stack formed by stacking a plurality of single cells in series, and the type of the stacks in the stack group is not limited in the embodiments of the present application. The fuel cell system can be applied to various types of stacks to meet the diversified needs and performance optimization needs in different application scenarios.

[0082] Further, as an optional embodiment, the number of stacks in each stage of the stack group and the stack group fuel utilization rate corresponding to each stage of the stack group satisfy a first stack number constraint condition, and the first stack number constraint condition is:

[0083] wherein M y represents the number of stacks in the D y stage of the stack group, M1 represents the number of stacks in the D1 stage of the stack group, μ j represents the stack group fuel utilization rate corresponding to the D j stage of the stack group, μ y represents the stack group fuel utilization rate corresponding to the D y stage of the stack group, μ1 represents the stack group fuel utilization rate corresponding to the D1 stage of the stack group, and j and y are positive integers and j∈[1, y-1].

[0084] Specifically, assuming that the stack group gas utilization rates corresponding to the D1, D2 to D y stages of the stack group are μ1, μ2 to μ y , the number of stacks M y of the D y stage of the stack group satisfies the following formula:

[0085] According to the above formula, the number of stacks M of the D y th stack group can be further set y to satisfy the following formula (i.e., the first stack number constraint condition):

[0086] It should be noted that, by designing the stack group fuel utilization rates of the stack groups at different levels to meet the first stack number constraint condition, the system can automatically achieve equal hydrogen amounts A0 of fuel consumed by each stack per unit time and equal output currents of each stack during normal operation without the need for individual control of the output currents of each stack.

[0087] Further as an optional implementation, the number of stacks in the front and rear stack groups and the stack fuel utilization rates corresponding to each stack in the front and rear stack groups satisfy a second stack number constraint condition, and the second stack number constraint condition is:

[0088] wherein M y represents the number of stacks in the D y th stack group, M y-1 represents the number of stacks in the D y-1 th stack group, δ j represents the stack fuel utilization rate corresponding to the jth stack in the D y-1 th stack group, and ξ j represents the stack fuel utilization rate corresponding to the jth stack in the D y th stack group, j and y are both positive integers, and j ∈ [1, M y-1 ].

[0089] Specifically, it is assumed that the D y-1 th stack group has M y-1 stacks, and the fuel utilization rates corresponding to each stack are δ1, δ2,..., δ (My-1) , the D y +1th stack group has M y stacks, and M y-1 > M y , and the cell fuel utilization rates corresponding to each cell are ξ1, ξ2,..., ξ (My) , then M y-1 satisfies the following formula (i.e., the second stack number constraint condition):

[0090] It should be noted that, by designing the number of fuel cells in two adjacent fuel cell stack groups and the fuel utilization rate of each fuel cell stack in the two adjacent fuel cell stack groups to meet the requirements of the second fuel cell stack quantity constraint, the system can automatically achieve the same amount of hydrogen A0 consumed by each fuel cell stack per unit time during normal operation, and achieve the same current output by each fuel cell stack, without the need for separate control of the output current for each fuel cell stack.

[0091] As an optional implementation, the system fuel utilization rate of the fuel cell system and the fuel utilization rate of each stack group satisfy the system fuel utilization rate constraint condition, which is:

[0092] Where, μ 总 M represents the system fuel utilization rate. j Indicates the Dth j The number of fuel cells in a fuel cell stack group, μ j Indicates the Dth j The fuel utilization rate of the fuel cell stack corresponding to the stack group, where j and y are positive integers and j∈[1, y].

[0093] Specifically, the system fuel utilization rate corresponding to the fuel cell system is μ 总 D1, D2 to D y The fuel cell stack utilization rates for the multi-stage stacks are μ1, μ2 to μ y Then the system fuel utilization rate η 总 The following formula (i.e., the system fuel utilization constraint) must be satisfied:

[0094] It should be noted that when the system fuel utilization rate of the fuel cell system and the fuel utilization rate of each stack group meet the above-mentioned system fuel utilization rate constraints, it can be ensured that the stacks of each stack group will not be overloaded, the lifespan of the stacks will be improved, and the overall utilization rate of the fuel cell system will be maintained.

[0095] As an optional implementation, the system fuel utilization rate satisfies 60% ≤ μ 总 ≤99% or 70% ≤μ 总 ≤95%, and the fuel utilization rate of each fuel cell stack group meets 30% ≤μ y ≤75% or 50% ≤μ y ≤75%, where μ y Indicates the Dth y The fuel utilization rate of the fuel cell stack corresponding to the stage stack, where y is a positive integer.

[0096] Specifically, the system fuel utilization rate of the fuel cell system is set to satisfy 60% ≤ μ 总≤ 99% or 70% ≤ μ 总 ≤ 95% to maximize fuel utilization within the range that the system can operate stably, reduce fuel consumption cost; set the fuel utilization rate of each level of stack group to satisfy 30% ≤ μ y ≤ 75% or 50% ≤ μ y ≤ 75% to optimize the fuel utilization rate distribution of each level of stack group, improve the overall fuel utilization rate and performance of the entire system.

[0097] Those skilled in the art can understand that the system fuel utilization rate and the fuel utilization rate of each level of stack group can also be selected according to actual needs.

[0098] Further as an optional implementation, the number of stacks in each level of stack group satisfies a third stack number constraint condition, the third stack number constraint condition is:

[0099] When the fuel cell system comprises a first level of stack group and a second level of stack group in series, the number of stacks in the first level of stack group and the number of stacks in the second level of stack group satisfy one of M1:M2 is 2:1, 3:1, 42:13, 39:12 or 4:1, wherein M1 represents the number of stacks in the first level of stack group, and M2 represents the number of stacks in the second level of stack group;

[0100] When the fuel cell system comprises a first level of stack group, a second level of stack group and a third level of stack group in series, the number of stacks in the first level of stack group, the number of stacks in the second level of stack group and the number of stacks in the third level of stack group satisfy one of M1:M2:M3 is 9:3:1, 39:12:4 or 42:13:4, wherein M1 represents the number of stacks in the stack group, M2 represents the number of stacks in the second level of stack group, and M3 represents the number of stacks in the third level of stack group.

[0101] Optionally, the fuel cell system in the embodiments of the present application further comprises a fuel supplement flow path, which is arranged on the third fuel flow path between two adjacent levels of stack groups. When the last level of stack group discharges residual fuel that cannot meet the requirement of "the equal hydrogen amount A0 of the consumed fuel of each stack per unit time" in the next level of stack group due to fluctuations or failures of the fuel cell system, the system can supplement the discharged fuel flow to the next level of stack group through the fuel supplement flow path.

[0102] Specifically, assuming that two adjacent levels of stack groups are D y-1 and D y , whether the D y level of stack group needs to be supplemented can be determined by the following formula. When the following formula is satisfied, the D y-1 and D yThe fuel supplement flow path between the two-stage stack groups is supplied with the supplement fuel, and the supplement fuel is mixed with the residual fuel discharged from the D y-1 th stage stack group and flows into the D y th stage stack group:

[0103] wherein μ y-1 represents the stack group fuel utilization ratio corresponding to the D y-1 th stage stack group, and μ y represents the stack group fuel utilization ratio corresponding to the D y th stage stack group.

[0104] Further, it is assumed that the stack group fuel utilization ratios corresponding to the D1, D2 to D y th stage stack groups are μ1, μ2 to μ y , respectively, then the number of stacks M y of the D y th stage stack group satisfies the following formula:

[0105] wherein Q y-1 represents the equal hydrogen amount of the supplement fuel supplied between the adjacent D y-1 th and D y th stage stack groups per unit time. When y≥3, the above formula is transformed, then the number of stacks M y of the D y th stage stack group satisfies the following formula:

[0106] wherein Q j represents the equal hydrogen amount of the supplement fuel supplied between the adjacent D j th and D j+1 th stage stack groups per unit time, j and k are positive integers, and j∈[1, y-1], k∈[2, y-1].

[0107] When y=2, the y=2 is substituted into the above formula, and the number of stacks M2 of the D2 stage stack group satisfies the following formula:

[0108] wherein Q1 represents the equal hydrogen amount of the supplement fuel supplied between the adjacent D1 and D2 stage stack groups per unit time.

[0109] It should be noted that when the system needs to supplement fuel, by designing the number of stacks of the adjacent two-stage stack groups, the stack group fuel utilization ratio of the adjacent two-stage stack groups, and the equal hydrogen amount of the supplement fuel needed between the adjacent two-stage stack groups to meet the requirements defined in the above formula, the system can automatically realize that the equal hydrogen amount A0 of the fuel consumed by each stack per unit time is equal when the system is abnormally operated, without the need for flow control by active devices.

[0110] Furthermore, the equivalent hydrogen quantity Q of the supplementary fuel j It satisfies the following formula (selected as the best):

[0111] Furthermore, let the Dth... y-1 The M-stage fuel cell stack has y-1 Each fuel cell stack has a fuel utilization rate of δ1, δ2 to δ... (My-1) D y The M-stage fuel cell stack has y Each fuel cell stack has a fuel utilization rate of ξ1, ξ2, and ξ3 respectively. (My) Then the Dth y Number of fuel cells M in a tiered fuel cell stack group y Satisfy the following formula:

[0112] It should be noted that when the system needs to be refueled, by designing the number of fuel cells in two adjacent fuel cell stack groups, the fuel utilization rate of each fuel cell in two adjacent fuel cell stack groups, and the equal amount of hydrogen required to be refueled between adjacent stages to meet the requirements of the above formula, the system can automatically achieve the same amount of hydrogen A0 consumed by each fuel cell stack per unit time during abnormal operation, and achieve the same current output by each fuel cell stack under normal operating conditions, without the need for separate control of the output current for each fuel cell stack.

[0113] The fuel cell system of the present application embodiment has been described above. It can be understood that, compared with fuel cell systems in the prior art, the present application forms a fuel cell system by connecting the fourth fuel flow paths of multiple fuel stacks in parallel to form a fuel stack group, and connecting the third fuel flow paths of multiple fuel stack groups in series. This allows the fuel exhaust gas discharged from the previous stage to flow into the next stage for reaction, enabling fuel recycling and improving fuel utilization and power generation efficiency. Furthermore, by limiting the amount of hydrogen consumed and the output current of each fuel stack to be equal per unit time, the risk of fuel stack over-utilization can be reduced, effectively improving fuel utilization and power generation efficiency while enhancing the stability and reliability of system operation.

[0114] In some alternative embodiments, the function / operations described in the block diagrams can not occur in the order described in the operational illustrations. For example, two blocks shown in succession can in fact be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality / operations involved. Also, although the embodiments presented in the flow diagrams are shown as a sequence of operations, it is to be understood that the logical flow is merely illustrative of alternative embodiments. The disclosed methods are not limited to the order of operations presented herein. Alternative embodiments are contemplated in which the order of operations is changed, and in which sub-operations are performed in different orders or in parallel.

[0115] Moreover, while the present application has been described with reference to the functional modules, it is to be understood that one or more of the above-described functions and / or features can be integrated in a single physical device and / or software module or one or more functions and / or features can be implemented in separate physical devices or software modules. It will also be appreciated that detailed discussion of the actual implementation of each module is not necessary for an understanding of the present application. Rather, the actual implementation is within the routine skill of engineers familiar with the property, function and internal relationships of the various functional modules disclosed herein. Accordingly, details concerning the actual implementation are not set forth herein other than understanding that such details are within the scope of the inventor's ordinary skill in the art and are contemplated as fall within the scope of the application as set forth in the appended claims. It is also to be understood that the specific concepts presented in the disclosure are intended to be illustrative only and not limiting of the scope of the application as set forth in the appended claims. The scope of the application is thus indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

[0116] If the above functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that makes a contribution to the prior art or the part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0117] The logic and / or steps represented in the flow diagrams or otherwise described herein, for example, can be embodied in non-transitory computer- readable media, executed by an instruction executing system, apparatus, or device, such as a computer-based system, a system with a processor, or other systems that can fetch and execute instructions from the instruction executing system, apparatus, or device, or in conjunction with the instruction executing system, apparatus, or device. For purposes of this specification, a "computer-readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction executing system, apparatus, or device.

[0118] More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can also be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, for example, via optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and stored in a computer memory.

[0119] It should be understood that aspects of the present application can be implemented in hardware, software, firmware or combinations thereof. In the above-described embodiments, multiple steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction executing system. For example, if implemented in hardware, and as in another embodiment, any of the following technologies known in the art, or combinations thereof, can be used: discrete logic circuitry having logic gates for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and the like.

[0120] In the above description of the present specification, the description referring to the terms "one embodiment", "another embodiment", or "certain embodiments" or the like means that the particular feature, structure, material or characteristic being described in connection with the embodiment or example is included in at least one embodiment or example of the present application. The illustrative appearances of the above-described terms in the description are not necessarily referred to the same embodiment or example throughout the specification. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0121] While the embodiments of the application have been shown and described, it is to be understood that the embodiments can be varied, modified, substituted and changed by those skilled in the art without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

[0122] The above is a specific description of the preferred embodiments of the application, but the application is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the application, and these equivalent modifications or substitutions are all included in the scope defined by the claims of the application.

Claims

1. A multi-stage stack of electrically connected structures, characterized in that, The battery array includes a plurality of single cells in parallel, and the battery array of each stage is communicated through the first fuel flow path, and the single cells in the battery array of the same stage are communicated through the second fuel flow path, wherein the number of single cells in the battery array of each stage and the array fuel utilization rate corresponding to the battery array of each stage satisfy a first single cell number constraint condition, and the number of single cells in the battery array of the front and rear stages and the battery fuel utilization rate corresponding to each single cell in the battery array of the front and rear stages satisfy a second single cell number constraint condition, so that the equal hydrogen amount of consumed fuel of each single cell per unit time is equal and the output current of each single cell is equal.

2. A multi-cell stack as claimed in claim 1, wherein, The number of single cells in each level of the battery array and the array fuel utilization corresponding to each level of the battery array satisfy the first single cell number constraint condition, and the first single cell number constraint condition is: wherein N x represents the number of single cells in the battery array at the C x level, N1 represents the number of single cells in the battery array at the C1 i level, η i represents the array fuel utilization of the battery array at the C x level, η1 represents the array fuel utilization of the battery array at the C1 x level, and i and x are positive integers and i∈[1, x-1].

3. A multi-cell stack structure of claim 1, wherein, The number of single cells in the front-stage battery array and the number of single cells in the rear-stage battery array satisfy a second single cell number constraint condition, which is that the utilization rates of the battery fuels corresponding to the single cells in the front-stage battery array and the single cells in the rear-stage battery array satisfy a second single cell utilization rate constraint condition, the second single cell utilization rate constraint condition being that: wherein N x represents the number of single cells in the battery array at the C x level, N x-1 represents the number of single cells in the battery array at the C x-1 level, γ i represents the number of single cells in the battery array at the C x-1 level, β i represents the battery fuel utilization corresponding to the i-th single cell in the battery array at the C x level, i and x are both positive integers and i ∈ [1, N x-1 ].

4. A multi-cell stack structure of claim 1, wherein, The stack fuel utilization corresponding to the stack fuel utilization and the array fuel utilization corresponding to the cell array of each stage satisfy a stack fuel utilization constraint condition, and the stack fuel utilization constraint condition is: wherein η 堆 represents the fuel utilization of the stack, N i represents the number of single cells in the C i th cell array, η i represents the fuel utilization of the C i th cell array, and i and x are positive integers and i ∈ [1, x].

5. A multi-cell stack structure according to claim 4, wherein The fuel utilization of the stack satisfies 60%≤η 堆 ≤99% or 70%≤η 堆 ≤95%, the array fuel utilization corresponding to the battery array at each stage satisfies 30%≤η x ≤75% or 50%≤η x ≤75%, wherein η x represents the array fuel utilization corresponding to the battery array at the C x th stage, and x is a positive integer.

6. A multi-cell stack structure of claim 1, wherein, The number of single cells in the battery array of each stage satisfies a third single cell number constraint condition, and the third single cell number constraint condition is: When the stack contains a first-stage battery array and a second-stage battery array in series, the number of single cells in the first-stage battery array and the number of single cells in the second-stage battery array satisfy one of N1:N2 is 2:1, 3:1, 42:13, 39:12 or 4:1, wherein N1 represents the number of single cells in the first-stage battery array, and N2 represents the number of single cells in the second-stage battery array; When the stack contains a first-stage battery array, a second-stage battery array and a third-stage battery array in series, the number of single cells in the first-stage battery array, the number of single cells in the second-stage battery array and the number of single cells in the third-stage battery array satisfy one of N1:N2:N3 is 9:3:1, 39:12:4 or 42:13:4, wherein N1 represents the number of single cells in the first-stage battery array, N2 represents the number of single cells in the second-stage battery array, and N3 represents the number of single cells in the third-stage battery array.

7. A multi-cascade fuel cell system, characterized in that, The stack group includes a plurality of stacks in parallel, and the stack group of each stage is communicated through the third fuel flow path, and the stacks in the stack group of the same stage are communicated through the fourth fuel flow path, wherein the number of stacks in the stack group of each stage and the stack group fuel utilization rate corresponding to the stack group of each stage satisfy a first stack number constraint condition, and the number of stacks in the stack group of the front and rear stages and the stack fuel utilization rate corresponding to each stack in the stack group of the front and rear stages satisfy a second stack number constraint condition, so that the equal hydrogen amount of consumed fuel of each stack per unit time is equal and the output current of each stack is equal.

8. A multi-cell fuel cell system according to claim 7, wherein The number of stacks in each level of the stack group and the corresponding stack group fuel utilization of each level of the stack group satisfy the first stack number constraint condition, and the first stack number constraint condition is: wherein M y represents the number of stacks in the stack group at the D y th level, M1 represents the number of stacks in the stack group at the D1 j th level, μ j represents the stack group fuel utilization ratio corresponding to the stack group at the D y th level, μ1 represents the stack group fuel utilization ratio corresponding to the stack group at the D1 y th level, and j and y are both positive integers and j ∈ [1, y-1].

9. The multi-stage series connection fuel cell system according to claim 7, wherein The number of the stacks in the front and rear stack groups and the stack fuel utilization corresponding to each of the stacks in the front and rear stack groups satisfy the second stack number constraint condition, the second stack number constraint condition being: M y represents the number of stacks in the stack group at the D y th stage, M y-1 represents the number of stacks in the stack group at the D y-1 th stage, δ j represents the number of stacks in the stack group at the D y-1 th stage, ξ j represents the stack fuel utilization corresponding to the jth stack in the stack group at the D y th stage, j and y are both positive integers and j∈[1, M y-1 ].

10. The multi-stage series connection fuel cell system according to claim 7, wherein The system fuel utilization corresponding to the fuel cell system and the stack group fuel utilization corresponding to each stage of the stack group satisfy a system fuel utilization constraint condition, the system fuel utilization constraint condition being: wherein μ 总 represents the system fuel utilization, M j represents the number of stacks in the D j th stack group, μ j represents the number of stacks in the D j th stack group, and j and y are positive integers and j ∈ [1, y].

11. A multi-cell fuel cell system according to claim 10, wherein The system fuel utilization rate satisfies 60%≤μ 总 ≤99% or 70%≤μ 总 ≤95%, and the fuel utilization rate of the corresponding electric pile group of each stage satisfies 30%≤μ y ≤75% or 50%≤μ y ≤75%, wherein μ y represents the fuel utilization rate of the corresponding electric pile group of the D y th stage, and y is a positive integer.

12. The multi-stage series connection fuel cell system according to claim 7, wherein The number of stacks in the stack group of each stage satisfies a third stack number constraint condition, and the third stack number constraint condition is: When the fuel cell system comprises a first-stage stack group and a second-stage stack group connected in series, the number of stacks in the first-stage stack group and the number of stacks in the second-stage stack group satisfy one of M1:M2 = 2:1, 3:1, 42:13, 39:12, or 4:1, where M1 represents the number of stacks in the first-stage stack group, and M2 represents the number of stacks in the second-stage stack group. When the fuel cell system comprises a first-stage stack group, a second-stage stack group, and a third-stage stack group connected in series, the number of stacks in the first-stage stack group, the number of stacks in the second-stage stack group, and the number of stacks in the third-stage stack group satisfy one of M1:M2:M3 = 9:3:1, 39:12:4, or 42:13:4, where M1 represents the number of stacks in the stack group, M2 represents the number of stacks in the second-stage stack group, and M3 represents the number of stacks in the third-stage stack group.

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