Cell stack having multi-cascade structure, and fuel cell system

Abstract

Disclosed in the present application are a cell stack having a multi-cascade structure, and a fuel cell system. The cell stack comprises a plurality of stages of cell arrays connected in series, first fuel flow paths and second fuel flow paths, wherein each stage of cell array comprises a plurality of single cells connected in parallel; the respective stages of cell arrays are in communication by means of the first fuel flow paths; the single cells in the same stage of cell array are in communication by means of the second fuel flow paths; and the number of single cells in each stage of cell array and an array fuel utilization rate corresponding to each stage of cell array meet a first single-cell number constraint condition, and the number of single cells in preceding and subsequent stages of cell arrays and a cell fuel utilization rate corresponding to each single cell in the preceding stage of cell array meet a second single-cell number constraint condition, such that the hydrogen-equivalent amount of fuel introduced into each single cell per unit time is equal. The present application can realize the recycling of fuel, and improve the fuel utilization rate and the power generation efficiency; moreover, the present application can reduce the risk of over-utilization of single cells and cell stacks, and can be widely used in 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. The battery arrays are 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 battery arrays of the previous and subsequent stages and the cell fuel utilization rate corresponding to each single cell in the battery array of the previous stage satisfy a second single cell number constraint condition. Thus, the equal hydrogen amount of fuel introduced into each single cell per unit time is equal when the stack is stably operated.

[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 as follows:

[0007] wherein N x represents the number of single cells in the battery array of the C x th stage, N1 represents the number of single cells in the battery array of the C1 irepresents the array fuel utilization ratio corresponding to the battery array at the C i th stage, i and x are both positive integers and i ∈ [1, x-1].

[0008] In some embodiments, the number of single cells in the battery array at the front stage and the back stage satisfies the second single cell number constraint condition, and the second single cell number constraint condition is:

[0009] wherein, N x represents the number of single cells in the battery array at the C x th stage, N x-1 represents the number of single cells in the battery array at the C x-1 th stage, γ i represents the array fuel utilization ratio corresponding to the battery array at the C x-1 th stage, i and x are both positive integers and i ∈ [1, N x-1 ].

[0010] In some embodiments, the stack fuel utilization ratio corresponding to the stack satisfies the stack fuel utilization ratio constraint condition with the array fuel utilization ratio corresponding to each stage of the battery array, and the stack fuel utilization ratio constraint condition is:

[0011] wherein, η 堆 represents the stack fuel utilization ratio, N i represents the number of single cells in the battery array at the C i th stage, η i represents the array fuel utilization ratio corresponding to the battery array at the C i th stage, i and x are both positive integers and i ∈ [1, x].

[0012] In some embodiments, the stack fuel utilization ratio satisfies 60%≤η 堆 ≤99% or 70%≤η 堆 ≤95%, the array fuel utilization ratio corresponding to each stage of the battery array satisfies 30%≤η x ≤75% or 50%≤η x ≤75%, wherein, η x represents the array fuel utilization ratio corresponding to the battery array at the C x th stage, and x is a positive integer.

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

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

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

[0016] To achieve the above object, another aspect of the embodiment of the present application proposes a fuel cell system with a multi-stage series 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 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 condition, 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 stack group satisfy a second stack number constraint condition, so that the equal hydrogen amount of fuel input into each of the stacks per unit time is equal when the fuel cell system is stably operated.

[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 condition, and the first stack number constraint condition 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, μ j represents the stack group fuel utilization rate corresponding to the D j th stack group, j and y are positive integers and j∈[1, y-1].

[0019] In some embodiments, the number of stacks in the stack group at the front stage and the back stage and the corresponding stack fuel utilization of each stack in the stack group at the front stage satisfy the second stack number constraint condition, the second stack number constraint condition being:

[0020] wherein 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, and δ j represents the stack fuel utilization corresponding to the jth stack in the stack group at the D y-1 th stage, j and y are positive integers, and j ∈ [1, M y-1 ].

[0021] In some embodiments, the system fuel utilization corresponding to the fuel cell system and the stack group fuel utilization corresponding to 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 represents the number of stacks in the stack group at the D j th stage, μ j represents the stack group fuel utilization corresponding to the stack group at the D j th stage, and 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 stack group fuel utilization corresponding to each stack group satisfies 30%≤ μ y ≤ 75% or 50%≤ μ y ≤ 75%, wherein μ y represents the stack group fuel utilization corresponding to the stack group at the D y th stage, and y is a positive integer.

[0024] In some embodiments, the number of stacks in each stack group satisfies the third stack number constraint condition, the third stack number constraint condition being:

[0025] 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 being 2:1, 3:1, 42:13, 39:12 or 4:1, wherein 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;

[0026] 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 being 9:3:1, 39:12:4 or 42:13:4, wherein M1 represents the number of stacks in the first-stage 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.

[0027] The application provides a multi-stage series structure stack, which has the following beneficial effects: the second fuel flow paths of multiple single cells are connected in parallel to form a cell array, the first fuel flow paths of multiple-stage cell arrays are connected in series to form a stack, fuel exhaust from an upper stage flows into a lower stage for reaction, fuel recycling is achieved, fuel utilization rate and power generation efficiency are improved, the number of single cells is limited by a number constraint condition to make the hydrogen equivalent amount of fuel flowing into each single cell in the stack per unit time equal, the risk of over-utilization of single cells is reduced, the fuel utilization rate and power generation efficiency are effectively improved, and the stability and reliability of stack operation are improved.

[0028] The application also provides a multi-stage series structure fuel cell system, which has the following beneficial effects: the fourth fuel flow paths of multiple stacks are connected in parallel to form a stack group, the third fuel flow paths of multiple-stage stack groups are connected in series to form a fuel cell system, fuel exhaust from an upper stage flows into a lower stage for reaction, fuel recycling is achieved, fuel utilization rate and power generation efficiency are improved, the number of stacks is limited by a number constraint condition to make the hydrogen equivalent amount of fuel flowing into each stack in the fuel cell system per unit time equal, the risk of over-utilization of stacks is reduced, the fuel utilization rate and power generation efficiency are effectively improved, and the stability and reliability of system operation are improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following introduces the drawings needed to be used in the embodiments of the application. It should be understood that the drawings introduced below are merely for facilitating clear description of some embodiments in the technical solutions of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0030] Fig. 1 is a structural schematic diagram of a multi-level series structure of an electric pile according to an embodiment of the present application;

[0031] Fig. 2 is a structural schematic diagram of a multi-level series structure of a fuel cell system according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to 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 implementation described in the following exemplary embodiments does not represent all the implementations consistent with the embodiments of the present application, but is only an example 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 "when" 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 an electric pile; one or more electric piles 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, power generation efficiency and fuel utilization rate of the fuel cell system and the electric pile, multiple electric piles or multiple single cells are usually designed in series and parallel, however, in the current design of the fuel cell system and the electric pile, the risk of imbalance of the number of electric piles and single cells often occurs, resulting in a decrease in the overall fuel utilization rate of the fuel cell system and the electric pile.

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

[0038] Referring to FIG. 1, which is a structural schematic diagram of a multi-stage series structure stack provided by the embodiment of the present application, the embodiment of the present application provides a multi-stage series structure stack, which comprises a plurality of cell arrays connected in series, a first fuel flow path and a second fuel flow path. Each cell array comprises a plurality of single cells connected in parallel. 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 cell arrays before and after a stage and the cell fuel utilization rate corresponding to each single cell in the cell array before the stage satisfy a second single cell number constraint condition, so that the equivalent hydrogen amount of fuel flowing into each single cell per unit time is equal when the stack is stably operated.

[0039] It should be noted that the equivalent hydrogen amount A0 is equal, which means that the amount of substance of fuel flowing into each single cell per unit time converted into equivalent hydrogen gas is equal. In addition, the arithmetic mean of the equivalent hydrogen amount of fuel flowing into 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 A0 of the fuel of the single cell is equal to that of each single cell.

[0040] When the array fuel utilization rate corresponding to the first stage cell array is greater than or equal to 50%, it is determined that the stack is stably operated.

[0041] Exemplarily, the stack of the embodiment of the present application comprises C1, C2 to C x a plurality of cell arrays, and the number of single cells in each cell array is N1, N2 to N x , and N1>N2>...>N x , N1, N2 to N x are all positive integers, and x≥2.

[0042] The fuel gas is input into each cell array in a series manner, and is input into each single cell of the cell array in a parallel manner in each cell array, so that the remaining fuel gas after reaction of the cell array of an upper stage flows into the cell array of a lower stage for reaction. Among them, the cell arrays Cx-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 battery array, where 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: N x =N x-1 ×(1-η x-1 )

[0046] Based on the above formula, we can further obtain the Cth... x The number of individual cells N in a multi-stage battery array x The following formula must be satisfied (i.e., the constraint on the number of the first single cell):

[0047] It should be noted that, by designing the fuel utilization rate of each stage of the battery array to meet the first single cell quantity constraint requirement, the fuel stack can automatically achieve equal hydrogen quantity A0 of fuel supplied to each single cell in each stage of the battery array per unit time during normal operation, without the need for flow control through active devices.

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

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

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

[0051] It should be noted that, by designing the number of single cells of the adjacent two-stage battery array and the fuel utilization rate of each single cell in the front stage battery array to meet the second single cell number constraint condition, the equal hydrogen amount A0 of the fuel flowing into each single cell per unit time can be automatically realized when the stack is normally running, without the need for flow control by active devices.

[0052] Further as an optional implementation, the stack fuel utilization rate corresponding to the stack and the array fuel utilization rate corresponding to each stage battery array satisfy a stack fuel utilization rate constraint condition, the stack fuel utilization rate constraint condition is:

[0053] wherein, η 堆 represents the stack fuel utilization rate, N i represents the number of single cells in the C i th stage battery array, η i represents the array fuel utilization rate corresponding to the C i th stage battery array, i and x are positive integers and i∈[1, x].

[0054] Specifically, the stack fuel utilization rate corresponding to the stack is η 堆 , C1, C2 to C xThe array fuel utilization rates of the multiple-stage cell arrays are η1, η2,..., and ηn, respectively. x The fuel utilization rate of the stack is η 堆 The following formula (i.e., the stack fuel utilization rate constraint condition) is satisfied:

[0055] It should be noted that when the stack fuel utilization rate of the stack and the array fuel utilization rates of the multiple-stage cell arrays meet the stack fuel utilization rate constraint condition, it can be ensured that the single cells of the multiple-stage cell arrays are not overloaded, the service life of the single cells is improved, and the overall stack maintains a high utilization rate.

[0056] Further, as an optional implementation, the stack fuel utilization rate satisfies 60%≤η 堆 ≤99% or 70%≤η 堆 ≤95%, and the array fuel utilization rates of the multiple-stage cell arrays satisfy 30%≤η x ≤75% or 50%≤η x ≤75%, where η x represents the array fuel utilization rate of the C x th cell array, and x is a positive integer.

[0057] Specifically, the stack fuel utilization rate of the stack satisfies 60%≤η 堆 ≤99% or 70%≤η 堆 ≤95% so that the fuel can be maximally utilized within the range in which the stack can stably operate, and the fuel consumption cost is reduced; and the array fuel utilization rates of the multiple-stage cell arrays satisfy 30%≤η x ≤75% or 50%≤η x ≤75% so that the fuel utilization rate distribution of the multiple-stage cell arrays is optimized, and the overall fuel utilization rate and performance of the entire stack are improved.

[0058] Those skilled in the art can understand that the limited ranges of the stack fuel utilization rate and the array fuel utilization rates of the multiple-stage cell arrays can also be selected according to actual needs.

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

[0060] When the stack includes a first-stage cell array and a second-stage cell array connected in series, the number of single cells in the first-stage cell array and the number of single cells in the second-stage cell array satisfy one of N1:N2=2:1, 3:1, 42:13, 39:12, or 4:1, where N1 represents the number of single cells in the first-stage cell array, and N2 represents the number of single cells in the second-stage cell array.

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

[0062] Optionally, the stack in the embodiment of the present application further comprises a fuel supplement flow path, which is arranged on the first fuel flow path between two adjacent cell arrays. When the stack operation fluctuates or fails, and the remaining fuel discharged from the upper cell array cannot satisfy the condition that the equal hydrogen amount A0 of fuel flowing into each single cell per unit time is equal in the lower cell array, the fuel supplement flow path can be used to make the remaining fuel discharged from the upper cell array mixed with the supplement fuel and then flow into the lower cell array.

[0063] Specifically, assuming that two adjacent cell arrays are C x-1 and C x , whether the cell array C x needs supplement fuel can be determined by the following formula. When the following formula is satisfied, the fuel supplement flow path between the cell arrays C x-1 and C x is used to supply the supplement fuel, which is mixed with the remaining fuel discharged from the cell array C x-1 and then flows into the cell array C x : N x >N x-1 ×(1-η x-1 )

[0064] where η x-1 represents the array fuel utilization rate corresponding to the cell array C x-1 .

[0065] Further, assuming that the array fuel utilization rates corresponding to the cell arrays C1, C2 to C x are η1, η2 to η x , respectively, the number of single cells N x of the cell array C x satisfies the following formula:

[0066] where Q x-1 represents the fuel flow rate per unit time of the cell array C x-1 and the cell array C xThe amount of hydrogen supplied as supplementary fuel between two adjacent battery array stages. When x≥3, the above formula is transformed to obtain the Cth stage. x The number of individual cells N in a multi-stage battery array x Satisfy the following formula:

[0067] Among them, Q i C represents the unit of time. i and C i+1 The amount of hydrogen supplied as supplementary fuel between two adjacent battery arrays is equal, where i and k are both positive integers, and i∈[1, x-1] and k∈[2, x-1].

[0068] When x = 2, substituting x = 2 into the above formula, the number of single cells N2 in the C2-level battery array satisfies the following formula:

[0069] Q1 represents the amount of hydrogen supplied as supplementary fuel between adjacent battery arrays C1 and C2 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 the two adjacent battery arrays, the array fuel utilization rate of the previous battery array, and the equal amount of hydrogen required to be refueled between the two adjacent stages to meet the requirements of the above formula, the fuel cell stack can automatically achieve the equal amount of hydrogen A0 of fuel supplied to each individual cell per unit time during abnormal operation, without the need for flow control through active devices.

[0071] Furthermore, the equivalent hydrogen quantity Q of the supplementary fuel i Satisfying the following formula (choose the optimal one): Q i ≥A0×[N i+1 -N i ×(1-η i )]

[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 γ(N) respectively. x-1 ), C x A battery array with N x If there is a single cell, then the Cth cell... 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 supplement fuel, by designing the number of single cells of the adjacent two-stage cell array, the fuel utilization rate of each single cell in the front-stage cell array, and the equivalent hydrogen amount of the fuel to be supplemented between the adjacent two stages to meet the requirements defined by the above formula, the fuel equivalent hydrogen amount A0 introduced into each single cell per unit time can be automatically equalized when the stack is abnormally operated, without the need for flow control by active devices.

[0074] The above describes the stack of the embodiments of the present application. It can be recognized that, compared with the stack in the prior art, the present application forms a cell array by connecting the second fuel flow paths of multiple single cells in parallel, forms a stack by connecting the first fuel flow paths of multiple-stage cell arrays in series, so that the fuel exhaust discharged by the upper stage flows into the lower stage for reaction, which can realize the recycling of fuel, improve fuel utilization rate and power generation efficiency; in addition, by limiting the equivalent hydrogen amount of fuel introduced into each single cell per unit time to be equal, the risk of over-utilization of single cells can be reduced, and the stability and reliability of stack operation can be improved while effectively improving fuel utilization rate and power generation efficiency.

[0075] The embodiments of the present application also propose a multi-stage series structure fuel cell system, which forms a stack group by connecting the fourth fuel flow paths of multiple stacks in parallel, forms a fuel cell system by connecting the third fuel flow paths of multiple-stage stack groups in series, so that the fuel exhaust discharged by the upper stage flows into the lower stage for reaction, which can realize the recycling of fuel, improve fuel utilization rate and power generation efficiency; in addition, by limiting the number of stacks to make the equivalent hydrogen amount of fuel introduced into each stack per unit time equal, the risk of over-utilization of stacks can be reduced, and the stability and reliability of system operation can be improved while effectively improving fuel utilization rate and power generation efficiency.

[0076] Referring to FIG. 2, FIG. 2 is a structural schematic diagram of a multi-stage series structure fuel cell system provided by the embodiments of the present application. The embodiments of the present application propose a multi-stage series structure fuel cell system, which includes multiple-stage series-connected stack groups, a third fuel flow path, and a fourth fuel flow path. Each stack group includes multiple parallel-connected stacks, each stack group is connected through the third fuel flow path, and the stacks in the same stack group are connected through the fourth fuel flow path. The number of stacks in each stack group and the corresponding stack group fuel utilization rate of each stack group satisfy a first stack number constraint condition, and the number of stacks in the front-stage and rear-stage stack groups and the corresponding stack fuel utilization rate of each stack in the front-stage stack group satisfy a second stack number constraint condition, so that the equivalent hydrogen amount of fuel introduced into each stack per unit time is equal when the fuel cell system is stably operated.

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

[0078] When the fuel utilization rate of the stack corresponding to the first stage is greater than or equal to 50%, it is determined that the fuel cell system is stably operated.

[0079] Exemplarily, the fuel cell system of the embodiment of the present application comprises D1, D2 to D y , and the number of stacks in each stage is M1, M2 to M y , respectively. y , M1>M2>...>M y , 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 the 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, the fuel communication between the adjacent two stages of the stack group D y-1 and D y is realized through the third fuel flow path, the fuel outlets of each stack in the D y-1 stage of the stack group are connected with the third fuel flow path through the fuel exhaust branch pipe, so that the fuel exhaust of each stack in the upper stage of the stack group is converged in the third fuel flow path; the fuel inlets of each stack in the D y stage of the stack group are connected 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 in the lower stage of the stack group.

[0081] It should be noted that the person skilled in the art can understand that the stacks in the stack group can be the stacks with the multi-stage cascade structure as mentioned above, or can be ordinary stacks without the multi-stage cascade structure, for example, a stack formed by stacking a plurality of single cells in series. The type of the stack in the stack group is not limited in the embodiment 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 fuel utilization rate of the stack group 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 yThe number of fuel cells in the D1 stage fuel cell group, M1 represents the number of fuel cells in the D1 stage fuel cell group, μ j Indicates the Dth j The fuel utilization rate of the fuel cell stack corresponding to the stack group, j and y are both positive integers and j∈[1, y-1].

[0084] Specifically, let D1, D2 to D y The fuel cell stack utilization rates for the multi-stage stacks are μ1, μ2 to μ y Then the Dth y Number of fuel cells M in a tiered fuel cell stack group y Satisfying the following formula: M y =M y-1 ×(1-μ y-1 )

[0085] Based on the above formula, we can further define the Dth... y Number of fuel cells M in a tiered fuel cell stack group y The following formula (i.e., the first fuel cell stack quantity constraint) must be satisfied:

[0086] It should be noted that, by designing the fuel utilization rate of each stage of the fuel cell stack to meet the requirements of the first fuel cell stack quantity constraint, the fuel cell stack can automatically achieve the same amount of hydrogen A0 in each stage of the fuel cell stack per unit time during normal operation, without the need for flow control through active devices.

[0087] As a further optional implementation, the number of fuel cells in the preceding and following stages of the fuel cell stack group and the fuel utilization rate of each fuel cell in the preceding stage fuel cell stack group satisfy a second fuel cell stack number constraint condition, which is:

[0088] Among them, M y Indicates the Dth y The number of fuel cells in a fuel cell stack group, M y-1 Indicates the Dth y-1 The number of fuel cells in a fuel cell stack group, δ j Indicates the Dth y-1 The fuel utilization rate of the j-th fuel cell in the fuel cell stack group, where j and y are both positive integers and j∈[1, M]. y-1 ].

[0089] Specifically, let D 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 If there are multiple fuel cells, then M ysatisfy the following formula (i.e., the second number of stacks constraint condition):

[0090] It should be noted that, by designing the number of stacks of the next stage stack group and the fuel utilization of each stack in the previous stage stack group to meet the second number of stacks constraint condition, the fuel cell system can automatically achieve equal hydrogen amount A0 of fuel input into each stack per unit time in normal operation without the need for flow control by active devices.

[0091] Further, as an optional embodiment, the system fuel utilization of the fuel cell system and the stack group fuel utilization of each stage stack group satisfy a system fuel utilization constraint condition, and the system fuel utilization constraint condition is:

[0092] wherein μ 总 represents the system fuel utilization, M j represents the number of stacks in the D j th stage stack group, μ j represents the stack group fuel utilization of the D j th stage stack group, j and y are positive integers, and j ∈ [1, y].

[0093] Specifically, the system fuel utilization of the fuel cell system is μ 总 , the stack group fuel utilization of the D1, D2,..., and D y th stage stack group is μ1, μ2,..., and μ y , and the system fuel utilization η 总 satisfies the following formula (i.e., the system fuel utilization constraint condition):

[0094] It should be noted that, when the system fuel utilization of the fuel cell system and the stack group fuel utilization of each stage stack group meet the above system fuel utilization constraint condition, the stacks of each stage stack group can be prevented from being overloaded, the life of the stacks can be improved, and the overall utilization of the fuel cell system can be maintained at a high level.

[0095] Further, as an optional embodiment, the system fuel utilization satisfies 60% ≤ μ 总 ≤ 99% or 70% ≤ μ 总 ≤ 95%, and the stack group fuel utilization of each stage stack group satisfies 30% ≤ μ y ≤ 75% or 50% ≤ μ y ≤ 75%, wherein μ y represents the stack group fuel utilization of the D y th stage stack group, and y is a positive integer.

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

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

[0098] Further as an optional implementation, the number of fuel cells in each fuel stack group satisfies a third fuel cell number constraint, and the third fuel cell number constraint is:

[0099] When the fuel cell system comprises a first fuel stack group and a second fuel stack group connected in series, the number of fuel cells in the first fuel stack group and the number of fuel cells in the second fuel stack group satisfy one of M1:M2=2:1, 3:1, 42:13, 39:12 or 4:1, where M1 represents the number of fuel cells in the first fuel stack group, and M2 represents the number of fuel cells in the second fuel stack group.

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

[0101] Optionally, the fuel cell system in the embodiments of the present application further comprises a fuel supplement flow path arranged on the third fuel flow path between two adjacent fuel stack groups. When the operation of the fuel cell system fluctuates or fails, and the remaining fuel discharged by the upper fuel stack group cannot satisfy the "equal hydrogen amount A0 of fuel passing into each fuel cell per unit time" in the lower fuel stack group, the remaining fuel discharged by the upper fuel stack group can be mixed with the supplement fuel and then flow into the lower fuel stack group through the fuel supplement flow path.

[0102] Specifically, let two adjacent fuel stack groups be D y-1 and D y , the D ywhether the multi-stage stack group needs to be supplemented with fuel. When the following formula is satisfied, the fuel cell system is controlled to D y-1 and D y The fuel supplement flow path between the two-stage stack groups is supplied with supplemental fuel, and the supplemental fuel is mixed with the remaining fuel discharged from the D y-1 stage stack group and flows into the D y stage stack group: M y >M y-1 x (1-μ y-1 )

[0103] wherein μ y-1 represents the stack group gas utilization rate corresponding to the D y-1 stage stack group.

[0104] Further, let the stack group gas utilization rates corresponding to the D1, D2 to D y stage stack groups be μ1, μ2 to μ y , respectively, then the number of stacks M y of the D y stage stack group satisfies the following formula:

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

[0106] wherein Q j represents the equivalent hydrogen amount of the supplemental fuel supplied between the adjacent D j and D j+1 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 equivalent hydrogen amount of the supplemental 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 be refueled, by designing the number of fuel cells in two adjacent fuel cell stacks, the fuel utilization rate of the previous fuel cell stack, and the equal amount of hydrogen required to be added between the two adjacent stacks to meet the requirements of the above formula, the system can automatically achieve the equal amount of hydrogen A0 of fuel introduced into each fuel cell stack per unit time during abnormal operation, without the need for flow control through active devices.

[0110] Furthermore, the equivalent hydrogen quantity Q of the supplementary fuel j Satisfying the following formula (choose the optimal one): Q j ≥A0×[M j+1 -M j ×(1-μ j )]

[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 Then the Dth fuel cell stack 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 stack in the previous fuel cell stack group, and the equal amount of hydrogen required to be added between the two adjacent stages to meet the requirements of the above formula, the system can automatically achieve the equal amount of hydrogen A0 of fuel introduced into each fuel cell stack per unit time during abnormal operation, without the need for flow control through active devices.

[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 fed into 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 alternative embodiments, the functions / operations in the flow diagrams can occur in different orders and / or concurrently with each other. For example, two operations shown in succession can in fact be executed substantially concurrently or the operations can sometimes be executed in the reverse order, depending upon the functionality / operations involved. Furthermore, embodiments are presented in the flow diagrams and descriptions herein as examples only, and it is understood that the disclosed methods are not limited to the order of operations or the exact logical flow presented herein. Alternative embodiments are possible, in which the order of operations is changed and / or in which some of the sub-operations described as being part of a larger operation are executed in a different order, or are executed concurrently with each other.

[0115] Furthermore, although the present application is described in the context of functional modules, it is understood that one or more of the functions and / or features described above 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, unless otherwise specified. It is also understood that detailed discussion of the actual implementation of each module is unnecessary to an understanding of the present application. Rather, the actual implementation is within the routine skill of engineers familiar with the attributes, functions, and internal relationships of the various functional modules disclosed herein. Accordingly, the present application is not limited to the details of the implementations described herein, but rather is limited only by the claims and their equivalents. Furthermore, the disclosed particular concepts are merely illustrative and are not intended to limit the scope of the present application, which is defined by the full scope of the appended claims and their equivalents.

[0116] The functions described above can be implemented in software and the software can be sold or used as a standalone product, which can be stored in one computer-readable storage medium. Based on such an understanding, the technical solutions of the present application, in essence, or the part of the technical solutions that make 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 plurality 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 described above in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), 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 execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions, or in conjunction with which the instructions can be executed. In the context of this specification, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-readable medium can be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium.

[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 embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies, known in the art, or their combinations can be used: a discrete logic circuit having logic gates for implementing logic functions on data signals, an application specific integrated circuit having appropriate combinational logic gates, a programmable gate array (PGA), a field programmable gate array (FPGA), or 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 specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. The illustrative expressions of the above terms do not necessarily refer to the same embodiment or example in the present specification. Also, the specific feature, structure, material or characteristic described can be combined in any one or more embodiments or examples in an appropriate manner.

[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 previous stage and the battery fuel utilization rate corresponding to each single cell in the battery array of the previous stage satisfy a second single cell number constraint condition, so that the equal hydrogen amount of fuel introduced into each single cell per unit time is equal when the stack is stably operated.

2. A multi-cell stack structure according to 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: Where, N x Indicates the Cth x The number of individual cells in the battery array of the C1th stage, N1 represents the number of individual cells in the battery array of the C1th stage, 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-1].

3. A multi-cell stack structure of claim 1, wherein, The number of single cells in the battery array of the front stage and the number of single cells in the battery array of the rear stage satisfy the second single cell number constraint condition, and the second single cell number constraint condition is that the utilization rate of battery fuel corresponding to each single cell in the battery array of the front stage and the utilization rate of battery fuel corresponding to each single cell in the battery array of the rear stage satisfy the second single cell number constraint condition. 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, 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 battery array, η i represents the fuel utilization of the C i th battery array, 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 includes 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 includes 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 previous stage and the stack fuel utilization rate corresponding to each stack in the stack group of the previous stage satisfy a second stack number constraint condition, so that the equal hydrogen amount of fuel introduced into each stack per unit time is equal when the fuel cell system is stably operated.

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, the first stack number constraint condition being: Among them, M y Indicates the Dth y The number of fuel cells in the fuel cell stack group of level D1, M1 represents the number of fuel cells in the fuel cell stack group of level D1, μ j Indicates the Dth j The fuel utilization rate of the fuel cell stack corresponding to the stack group is given by the following: 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 electric piles in the front and rear electric pile groups and the electric pile fuel utilization rate corresponding to each electric pile in the front electric pile group satisfy the second electric pile number constraint condition, and the second electric pile number constraint condition is: M y represents the number of stacks in the stack group at the D y th level, M y-1 represents the number of stacks in the stack group at the D y-1 th level, δ j represents the number of stacks in the stack group at the D y-1 th level, 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 stack fuel utilization corresponding to 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.

Images