Method and device for optimizing influence parameters of cascaded SOFC (Solid Oxide Fuel Cell) system

Abstract

The invention discloses an influence parameter optimization method and device for a cascaded SOFC system, the method is applied to the cascaded SOFC system, and the method comprises the steps: obtaining influence parameters of the cascaded SOFC system, the influence parameters at least comprising a battery number ratio and a shunt ratio of a first-stage electric pile and a second-stage electric pile; the influence parameters are sequentially changed, a pre-established target system model is utilized, the system electric efficiency and the average net power under the condition that the influence parameters are changed are calculated, the target system model is established according to the net alternating current power of the system, and the net alternating current power of the system is determined at least according to the total power generation power of the first-stage electric pile and the second-stage electric pile; and screening a target influence parameter from the changed influence parameters according to the calculated system electrical efficiency and the calculated on-chip net power. According to the method, the influence parameters of the cascaded SOFC system can be optimized, so that the requirements of different application scenes can be met, the electric efficiency of the cascaded SOFC system is effectively improved, and the operation cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of energy and power technology, and in particular to a method and apparatus for optimizing the influence parameters of a cascaded SOFC system. Background Technology

[0002] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] Solid oxide fuel cells (SOFCs) are electrochemical devices that directly convert the chemical energy of fuel into electrical energy, offering advantages such as high energy conversion efficiency and environmental friendliness (low SOx and NOx emissions, and no noise pollution). SOFC systems can provide high-quality thermal energy resources while efficiently generating electricity, achieving a combined supply of power and heat. However, traditional SOFC systems (such as multi-stack SOFC systems with parallel stacks) cannot fully utilize the fuel (>80%), and there is still room for improvement in system electrical efficiency. Cascaded SOFC systems, by cascading SOFC stacks, can effectively improve the electrical efficiency of SOFC systems compared to the traditional parallel connection method.

[0004] However, existing technologies cannot optimize the influencing parameters (parameters that affect the output voltage of a single battery stack in a cascaded SOFC system) for cascaded SOFC systems. As a result, cascaded SOFC systems cannot meet the needs of different application scenarios (most existing cascaded SOFC systems have fixed structures and do not optimize with the optimization of influencing parameters), resulting in relatively low system electrical efficiency and relatively high operating costs.

[0005] There is currently no effective solution to the above problems. Summary of the Invention

[0006] This specification provides a method and apparatus for optimizing the influence parameters of a cascaded SOFC system, in order to solve the problems that existing technologies cannot optimize the influence parameters of cascaded SOFC systems, thus failing to meet the needs of different application scenarios, and that cascaded SOFC systems have relatively low electrical efficiency and relatively high operating costs.

[0007] In a first aspect, the embodiments of this specification provide a method for optimizing the influence parameters of a cascaded SOFC system, which is applied to a cascaded SOFC system, wherein the cascaded SOFC system includes at least: a first-stage fuel flow path, a second-stage fuel flow path, and a first-stage fuel exhaust flow path;

[0008] The method comprises: a fuel bypass valve and a first-stage fuel cell stack connected sequentially along the fuel flow path of the first-stage fuel cell stack; a fuel bypass valve and a second-stage fuel cell stack connected sequentially along the fuel flow path of the second-stage fuel cell stack; and a first-stage fuel cell stack and a second-stage fuel cell stack connected sequentially along the fuel exhaust flow path of the first-stage fuel cell stack. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage fuel cell stack and the second-stage fuel cell stack.

[0009] Obtain the influence parameters of the cascaded SOFC system, including at least the ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack, and the shunt ratio characterizing the opening of the fuel bypass valve;

[0010] By sequentially changing the influencing parameters, and using a pre-established target system model, the system electrical efficiency and net power per unit under the changed influencing parameters are calculated. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack.

[0011] Based on the calculated system electrical efficiency and net power per chip, target influencing parameters are selected from the changed influencing parameters, wherein the system electrical efficiency and net power per chip corresponding to the target influencing parameters are greater than the corresponding preset threshold.

[0012] In some embodiments, the influencing parameters further include: average fuel flow per cell, lower limit of operating voltage, and upper limit of battery fuel utilization rate;

[0013] Accordingly, the sequential changing of the influencing parameters includes:

[0014] Using the controlled variable method, the average fuel flow rate per cell, the ratio of the number of cells, the current split ratio, the lower limit of the operating voltage, and the upper limit of the battery fuel utilization rate are changed sequentially.

[0015] In some embodiments, the total power generation of the first-stage fuel cell stack and the second-stage fuel cell stack is determined according to the following formula:

[0016] P SOFC =Max(V cell,1 j ,1 A cell,1 N cell,1 +V cell,2 j ,2 A cell,2 N cell,2 )

[0017] Among them, P SOFC V represents the total power output of the first-stage and second-stage fuel cell stacks. cell,1 j1 is the single-cell output voltage of the first-stage fuel cell stack; j2 is the current density of the first-stage fuel cell stack; A cell,1N represents the area of ​​a single battery cell in the first-stage fuel cell stack. cell,1 V represents the number of cells in a single first-stage fuel cell stack. cell,2 J is the single-cell output voltage of the second-stage fuel cell; J2 is the current density of the second-stage fuel cell; N cell,2 This represents the number of cells per cell in the second-stage stack; Max is the maximum value.

[0018] In some embodiments, the net AC power of the system is further determined based on the blower power corresponding to the blower in the air flow path of the cascaded SOFC system. The blower is used to pressurize the air in the air flow path so that the pressurized air is delivered to the first stage fuel cell stack and the second stage fuel cell stack.

[0019] Accordingly, the net AC power of the system is determined at least based on the total power generation of the first-stage and second-stage fuel cell stacks, including:

[0020] The net AC power of the system is determined based on the total power output of the first-stage and second-stage fuel cell stacks and the power output of the blower.

[0021] In some embodiments, determining the net AC power of the system based on the total power generation of the first-stage fuel cell stack and the second-stage fuel cell stack, and the blower power, includes:

[0022] The net AC power of the system is determined using the following formula:

[0023] P system,AC =P SOFC η DC / AC -P blower

[0024] Among them, P system,AC P is the net AC power of the system. SOFC η represents the total power output of the first-stage and second-stage fuel cell stacks. DC / AC P represents the system's DC to AC conversion efficiency. blower This refers to the power of the blower.

[0025] In some embodiments, calculating the average net power per chip under varying influence parameters using a pre-established target system model includes:

[0026] Using the target system model, calculate the net AC power of the system under different influencing parameters;

[0027] Based on the net AC power, the average net power per cell under the changed influencing parameters is determined according to the following formula:

[0028]

[0029] Among them, P cell,netNet power per chip; N cell,1 N represents the number of cells in a single first-stage fuel cell stack. cell,2 P represents the number of cells per stack in the second-stage fuel cell stack. system,AC This represents the net AC power of the system.

[0030] In some embodiments, the method further includes:

[0031] Select the target battery number ratio and target current shunting ratio from the target impact parameters, and formulate an optimization scheme for the cascaded SOFC system based on the target battery number ratio and target current shunting ratio;

[0032] Based on the aforementioned cascaded SOFC system optimization scheme, the current cascaded SOFC system structure is optimized to obtain the optimized target cascaded SOFC system.

[0033] Secondly, embodiments of this specification also provide a cascaded SOFC device, which includes at least: a first-stage fuel flow path, a second-stage fuel flow path, and a first-stage fuel exhaust flow path;

[0034] The system comprises a fuel bypass valve and a first-stage fuel cell stack connected sequentially along the fuel flow path of the first-stage fuel cell stack; a fuel bypass valve and a second-stage fuel cell stack connected sequentially along the fuel flow path of the second-stage fuel cell stack; and a first-stage fuel cell stack and a second-stage fuel cell stack connected sequentially along the fuel exhaust flow path of the first-stage fuel cell stack. The first-stage and second-stage fuel cell stacks are connected in series. The fuel bypass valve is used to regulate the ratio of fuel entering the first-stage and second-stage fuel cell stacks.

[0035] Thirdly, the embodiments of this specification also provide an influence parameter optimization device for a cascaded SOFC system, which is applied to a cascaded SOFC system, wherein the cascaded SOFC system includes at least: a first-stage fuel flow path, a second-stage fuel flow path, and a first-stage fuel exhaust flow path;

[0036] The device comprises: a fuel bypass valve and a first-stage fuel cell stack connected sequentially along the fuel flow path of the first-stage fuel cell stack; a fuel bypass valve and a second-stage fuel cell stack connected sequentially along the fuel flow path of the second-stage fuel cell stack; and a first-stage fuel cell stack and a second-stage fuel cell stack connected sequentially along the fuel exhaust flow path of the first-stage fuel cell stack. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage fuel cell stack and the second-stage fuel cell stack. The device includes:

[0037] The acquisition module is used to acquire the influence parameters of the cascaded SOFC system. The influence parameters include at least the ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack, and the shunt ratio characterizing the opening degree of the fuel bypass valve.

[0038] The calculation module is used to change the influencing parameters in sequence and calculate the system electrical efficiency and net power per unit under the changed influencing parameters using a pre-established target system model. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack.

[0039] The filtering module is used to filter target impact parameters from the changed impact parameters based on the calculated system electrical efficiency and net power per chip, wherein the system electrical efficiency and net power per chip corresponding to the target impact parameters are greater than the corresponding preset threshold.

[0040] Fourthly, embodiments of this specification also provide a computer-readable storage medium storing a computer program / instructions thereon, which, when executed by a processor, implements the steps of the above-described method for optimizing the impact parameters of a cascaded SOFC system.

[0041] This specification provides a method and apparatus for optimizing the influence parameters of a cascaded SOFC system. The method is applied to a cascaded SOFC system, which includes at least: a first-stage fuel cell stack fuel flow path, a second-stage fuel cell stack fuel flow path, and a first-stage fuel cell stack exhaust flow path. A fuel bypass valve and a first-stage fuel cell stack are sequentially connected along the first-stage fuel cell stack fuel flow path; a fuel bypass valve and a second-stage fuel cell stack are sequentially connected along the second-stage fuel cell stack fuel flow path; and a first-stage fuel cell stack and a second-stage fuel cell stack are sequentially connected along the first-stage fuel cell stack exhaust flow path. The first-stage and second-stage fuel cell stacks are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage and second-stage fuel cell stacks. The method includes: acquiring the influencing parameters of the cascaded SOFC system, wherein the influencing parameters include at least the ratio of the number of cells in the first-stage stack to the second-stage stack, and the shunt ratio characterizing the opening of the fuel bypass valve; sequentially changing the influencing parameters, and using a pre-established target system model, calculating the system electrical efficiency and net power per cell under the changed influencing parameters, wherein the target system model is established based on the system's net AC power, and the system's net AC power is determined at least based on the total power generation of the first-stage stack and the second-stage stack; and selecting target influencing parameters from the changed influencing parameters based on the calculated system electrical efficiency and net power per cell, wherein the system electrical efficiency and net power per cell corresponding to the target influencing parameters are greater than the corresponding preset thresholds. Through the above scheme, the influencing parameters of the cascaded SOFC system can be optimized, thereby meeting the needs of different application scenarios, effectively improving the electrical efficiency of the cascaded SOFC system, and reducing operating costs. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0043] Figure 1 This is a schematic diagram of the structural composition of a cascaded SOFC system provided in the embodiments of this specification;

[0044] Figure 2 This is a flowchart illustrating a method for optimizing the impact parameters of a cascaded SOFC system, as provided in the embodiments of this specification.

[0045] Figure 3 This is a schematic diagram showing the inlet and outlet temperatures, as well as the location of the module, provided in the embodiments of this specification.

[0046] Figure 4 This is a schematic diagram of the optimized 10kW cascaded SOFC system provided in the embodiments of this specification;

[0047] Figure 5 This is a schematic diagram of the structural composition of an influence parameter optimization device for a cascaded SOFC system provided in the embodiments of this specification;

[0048] Figure 6 This is a schematic diagram of the structural composition of the electronic device provided in the embodiments of this specification.

[0049] [Explanation of Labels in the Attached Image]

[0050] 1. Air blower; 2. Fuel cylinder or fuel pump; 3. First stage fuel cell stack; 4. Second stage fuel cell stack; 5. Burner; 6. First heat exchanger; 7. Second heat exchanger; 8. Condenser; 9. Fuel bypass valve. Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0052] Solid oxide fuel cells (SOFCs) are electrochemical devices that directly convert the chemical energy of fuel into electrical energy. They offer advantages such as high energy conversion efficiency and environmental friendliness (low SOx and NOx emissions, no noise pollution), making them promising for distributed combined heat and power (CHP) systems. SOFCs utilize an all-solid-state ceramic structure, offering high safety, low cost, and ease of modularization, giving them a significant advantage in kilowatt-level distributed power generation systems. The core area of ​​a SOFC operates at 700℃-800℃, generating high-quality waste heat from exhaust gases. Therefore, SOFC systems can provide high-quality thermal energy resources while efficiently generating electricity, achieving a combined supply of power and heat. However, traditional SOFC systems fail to fully utilize fuel (>80%), leaving room for improvement in electrical efficiency. Cascaded SOFC systems, by connecting SOFC stacks in cascades, can effectively improve the electrical efficiency of SOFC systems compared to traditional parallel connections.

[0053] However, existing technologies cannot optimize the influencing parameters (parameters that affect the output voltage of a single battery stack in a cascaded SOFC system) for cascaded SOFC systems. As a result, cascaded SOFC systems cannot meet the needs of different application scenarios (most existing cascaded SOFC systems have fixed structures and do not optimize with the optimization of influencing parameters), resulting in relatively low system electrical efficiency and relatively high operating costs.

[0054] To address the aforementioned problems with existing methods and the specific reasons for these problems, this application proposes a method and apparatus for optimizing the influence parameters of a cascaded SOFC system. This method can optimize the influence parameters of the cascaded SOFC system, and then determine the optimal cascaded SOFC system structure based on the optimized influence parameters (i.e., the aforementioned target influence parameters). This allows the cascaded SOFC system to meet the needs of different application scenarios, effectively improve the electrical efficiency of the cascaded SOFC system, and reduce operating costs.

[0055] To better understand the inventive concept of this application, a cascaded SOFC system provided in the embodiments of this specification is first introduced. For example... Figure 1 As shown, a cascaded SOFC system may include at least: a first-stage fuel flow path (2), a second-stage fuel flow path (3), and a first-stage fuel exhaust flow path (4);

[0056] The fuel bypass valve 9 and the first-stage fuel cell stack 3 are connected in sequence along the fuel flow path (2) of the first-stage fuel cell stack, the fuel bypass valve 9 and the second-stage fuel cell stack 4 are connected in sequence along the fuel flow path (3) of the second-stage fuel cell stack, and the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4 are connected in sequence along the fuel exhaust flow path (4) of the first-stage fuel cell stack. The first-stage fuel cell stack 3 and the second-stage fuel cell stack 4 are connected in series. The fuel bypass valve 9 is used to adjust the ratio of fuel entering the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4.

[0057] It should be noted that, Figure 1 The cascaded SOFC system shown can be a typical cascaded SOFC system that can be optimized, such as: Figure 1 The battery number ratio and shunt ratio of the cascaded SOFC system shown (to be explained later) are as follows: Figure 1 The cascaded SOFC system shown has an adjustable cell ratio and shunt ratio. Compared to the fixed cell ratio (e.g., any given cell ratio of 1:1, 2:1, or 3:1) and fixed shunt ratio in existing cascaded SOFC systems, this application can quantitatively compare the impact of different cell ratios on the performance of the cascaded SOFC system, thereby designing the optimal cascaded SOFC system structure. Based on a suitable cell ratio and shunt ratio, the fuel flow rate and fuel quality of the first and second stage stacks of the cascaded SOFC system are matched, effectively maximizing the power generation performance of both stages.

[0058] In some embodiments, the first-stage fuel cell stack 3 (or first-stage fuel cell stack) and the second-stage fuel cell stack 4 (or second-stage fuel cell stack) may each have multiple stacks, and each stack may consist of multiple individual cells. The cell number ratio may be the ratio of the number of first-stage fuel cell stacks 3 to the number of second-stage fuel cell stacks 4 (or the ratio of the total number of cells in the first-stage fuel cell stack 3 to the total number of cells in the second-stage fuel cell stack 4).

[0059] In some embodiments, a second heat exchanger 7 is connected before the fuel bypass valve 9 in the first-stage fuel stack fuel flow path (2) and the second-stage fuel stack fuel flow path (3), which can be used to preheat the fuel before it enters the first-stage or second-stage fuel stack. The cascaded SOFC system may also include: a main fuel flow path (1), an air flow path (6), a second-stage fuel tail gas flow path (5), a fuel stack air tail gas flow path (7), a burner tail gas flow path (8), and a hot water flow path (9).

[0060] Along the main fuel flow path (1), fuel cylinder or fuel pump 2 and second heat exchanger 7 are connected in sequence. Fuel cylinder or fuel pump 2 stores fuel and can deliver fuel to second heat exchanger 7. Second heat exchanger 7 heats up to preheat the fuel, and then enters first stage fuel cell stack 3 and second stage fuel cell stack 4 through fuel bypass valve 9. Fuel bypass valve 9 can adjust the proportion of fuel going to or entering first stage fuel cell stack 3 and second stage fuel cell stack 4.

[0061] A blower 1, a first heat exchanger 6, and a first-stage fuel cell stack 3 are sequentially connected along the air flow path (6). The air flow path (6) and the main fuel flow path (1) are connected in parallel, that is, the first heat exchanger 6 and the second heat exchanger 7 are connected in parallel. The air in the air flow path (6) can be pressurized by the blower 1 and first transported to the first heat exchanger 6. The first heat exchanger 6 heats up to preheat the air, and then it is transported to the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4. Finally, the anode fuel and the cathode air can undergo an electrochemical reaction in the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4 to generate electrical energy.

[0062] A second-stage fuel cell stack 4, a second heat exchanger 7, and a burner 5 are sequentially connected along the fuel exhaust gas path (5) of the second-stage fuel cell stack. The burner 5 is located after the second-stage fuel cell stack 4. The anode fuel exhaust gas from the second-stage fuel cell stack 4 in the fuel exhaust gas path (5) can be heat-exchanged by the second heat exchanger 7 before being transported to the burner 5. A first-stage fuel cell stack 3 or a second-stage fuel cell stack 4 and a burner 5 are sequentially connected along the fuel exhaust gas path (7). The cathode air exhaust gas from the two-stage fuel cell stack (first-stage fuel cell stack 3 and second-stage fuel cell stack 4) can enter the burner 5 through this path and react with the anode fuel exhaust gas from the second-stage fuel cell stack 4 entering the burner 5.

[0063] A gasifier 5, a first heat exchanger 6, and a condenser 8 are connected sequentially along the burner exhaust gas path (8). The exhaust gas generated by the burner 5 can first enter the first heat exchanger 6 to exchange heat with the fuel cell stack air exhaust gas path (7), and then enter the condenser 8 for heat exchange.

[0064] The hot water flow path (9) involves a condenser 8. A suitable amount of cold water exchanges heat (8) with the burner exhaust flow path through the hot water flow path (9) to generate hot water.

[0065] The above-mentioned first-stage fuel tail gas flow path (4) involves the first-stage fuel stack and the second-stage fuel stack. The fuel that has not been fully reacted in the first-stage fuel stack 3 can enter the second-stage fuel stack 4 along with the anode fuel tail gas (anode tail gas), mix with the fuel in the second-stage fuel stack 4, and continue to react with the air.

[0066] In a cascaded SOFC system, the unused fuel in the anode exhaust gas of the first-stage stack 3 is fully utilized after entering the second-stage stack 4. Compared to a conventional SOFC system, this significantly improves the fuel utilization rate and thus the electrical efficiency of the cascaded SOFC system. Furthermore, the fuel bypass valve 9 can adjust the appropriate fuel supply ratio (or fuel distribution ratio) between the first-stage stack 3 and the second-stage stack 4, thus laying the foundation for determining the optimal split ratio and obtaining a cascaded SOFC system with the optimal structure.

[0067] In some embodiments, the above-described cascaded SOFC system is not limited by the type of fuel for more efficient fuel utilization. It can be configured with a suitable external reformer, and hydrogen fuel, hydrocarbon fuel, and ammonia fuel are all applicable to this cascaded system.

[0068] For the aforementioned cascaded SOFC system, this specification proposes an optimization method for the influence parameters of the cascaded SOFC system. Figure 2 This is a flowchart illustrating a method for optimizing the impact parameters of a cascaded SOFC system provided in the embodiments of this specification. Although this specification provides method operation steps or apparatus structures as shown in the following embodiments or figures, based on conventional or non-inventive effort, the method or apparatus may include more or fewer operation steps or module units after partial merging. In steps or structures where there is no logically necessary causal relationship, the execution order of these steps or the module structure of the apparatus is not limited to the execution order or module structure shown in the embodiments or figures of this specification. When the method or module structure is applied in actual devices, servers, or terminal products, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiments or figures (e.g., in a parallel processor or multi-threaded processing environment, or even in a distributed processing or server cluster implementation environment). For specific implementation, please refer to... Figure 2 As shown, the method applied to a cascaded SOFC system may include the following:

[0069] S201: Obtain the influence parameters of the cascaded SOFC system, the influence parameters including at least the ratio of the number of cells in the first-stage stack and the second-stage stack, and the shunt ratio characterizing the opening degree of the fuel bypass valve;

[0070] S202: Change the influencing parameters in sequence, and use the pre-established target system model to calculate the system electrical efficiency and net power per unit under the changed influencing parameters. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack.

[0071] S203: Based on the calculated system electrical efficiency and net power per chip, select target influencing parameters from the changed influencing parameters, wherein the system electrical efficiency and net power per chip corresponding to the target influencing parameters are greater than the corresponding preset threshold.

[0072] In some embodiments, the influencing parameters in S201 above may also include: average fuel flow rate per cell, lower limit of operating voltage, and upper limit of battery fuel utilization rate;

[0073] Accordingly, the sequential changing of the influencing parameters in S202 above can, in specific implementation, include:

[0074] Using the controlled variable method, the average fuel flow rate per cell, the ratio of the number of cells, the current split ratio, the lower limit of the operating voltage, and the upper limit of the battery fuel utilization rate are changed sequentially.

[0075] In some embodiments, the aforementioned influencing parameters can be parameters affecting the output voltage of a single battery stack in a cascaded SOFC system, and may include design parameters and operating parameters. Design parameters may include, but are not limited to, the ratio of the number of batteries in the first-stage and second-stage battery stacks, and the shunting ratio characterizing the opening of the fuel bypass valve. Operating parameters may include, but are not limited to, the average fuel flow rate per cell, the lower limit of the operating voltage, and the upper limit of battery fuel utilization. The battery number ratio can be the ratio of the number of batteries in the first-stage battery stack to the number of batteries in the second-stage battery stack (or the ratio of the total number of batteries in the first-stage battery stack to the total number of batteries in the second-stage battery stack), and the shunting ratio can be the ratio of the total fuel flow rate of the first-stage battery stack to the total fuel flow rate of the system.

[0076] The controlled variable method can be used to sequentially change the average fuel flow rate per cell, the cell number ratio, the shunt ratio, the lower limit of the operating voltage, and the upper limit of the battery fuel utilization rate. Using a pre-established target system model (i.e., the cascaded SOFC system model), the system electrical efficiency (i.e., the electrical efficiency of the cascaded SOFC system) and the net power per cell under the changed influencing parameters can be calculated. Finally, the target influencing parameters can be selected from the changed influencing parameters. That is, the influencing parameters corresponding to the highest system electrical efficiency and the net power per cell, or those reaching the ideal value, can be selected. In other words, the system electrical efficiency and the net power per cell corresponding to the target influencing parameters are greater than the corresponding preset thresholds. For example, the system electrical efficiency can be greater than the first preset threshold, and the net power per cell can be greater than the second preset threshold. The first preset threshold and the second preset threshold can be different, but both can be set according to actual needs. This manual does not make specific limitations on this.

[0077] Specifically, the average fuel flow rate per cell can be changed first (e.g., within a first numerical range (0.1L / min-1.5L / min) by changing the average fuel flow rate per cell), while keeping the battery number ratio, shunt ratio, lower operating voltage limit, and upper battery fuel utilization rate constant. The system electrical efficiency and net power per cell under the changed average fuel flow rate can be calculated (i.e., the system electrical efficiency and net power per cell under different average fuel flow rates can be obtained). Then, from the changed average fuel flow rates, the average fuel flow rate corresponding to the highest system electrical efficiency and net power per cell or reaching the ideal value can be selected (i.e., the optimal average fuel flow rate per cell; there can be multiple optimal average fuel flow rates per cell, such as the optimal average fuel flow rate per cell within the range of 0.2L / min-0.6L / min). This optimal average fuel flow rate per cell can be used as the target influencing parameter. Then, other optimal parameters can be determined under the optimal average fuel flow rate (e.g., within 0.2L / min-0.6L / min). By analogy, the optimal cell number ratio, optimal shunt ratio, optimal average fuel flow rate, optimal lower operating voltage limit, and optimal upper battery fuel utilization rate can be ultimately selected. In other words, multiple target influencing parameters can be identified, and these multiple parameters can be combined to form the optimal target influencing parameter combination. Selecting multiple target influencing parameters lays the foundation for subsequently determining the optimal structure of a cascaded SOFC system, meeting the needs of different application scenarios, and reducing operating costs.

[0078] It should be noted that when changing the aforementioned influencing parameters in sequence and using a pre-established target system model to calculate the system electrical efficiency and net power per chip under the changed influencing parameters, preset constraints must also be met.

[0079] The preset constraints may include, but are not limited to: stack inlet gas temperature difference constraints, burner maximum temperature constraints, battery voltage lower limit constraints, and battery fuel utilization upper limit constraints. These constraints comprehensively consider four aspects of stack operation safety and lifespan requirements, ensuring long-term operation of the stack batteries, reducing stress generated during high-temperature stack operation, and slowing down the aging of heat-sensitive components in the stack. Compared with existing engineering technologies, these constraints are more comprehensive.

[0080] Specifically, the preset constraints can be shown in Table 1:

[0081] Table 1 Preset Constraints

[0082]

[0083]

[0084] The temperature difference constraint for the fuel cell inlet gas can be set to no more than 200℃ (i.e., the temperature difference between the anode inlet and anode outlet should not exceed 200℃, and the temperature difference between the cathode inlet and cathode outlet should not exceed 200℃, as shown in Table 1). See [reference needed]. Figure 3As shown, the cathode inlet temperature is the same as the cold end outlet temperature of the first cathode heat exchanger 6, the anode inlet temperature is the same as the cold end outlet temperature of the second anode heat exchanger 7, and the anode outlet temperature or cathode outlet temperature follows the first-stage stack 3 or the second-stage stack 4. The maximum temperature of the burner 5 shall not exceed 1000℃, the lower limit of the battery voltage shall be constrained between 0.7V and 0.8V, and the upper limit of the battery fuel utilization rate shall be constrained between 60% and 80%.

[0085] In some embodiments, the target system model (i.e., the cascaded SOFC system model) in S202 above may include an electrochemical sub-model. The target system model may consist of two parts: a fuel cell stack model (i.e., a fuel cell stack model obtained by modeling the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4) and an auxiliary component model of the cascaded SOFC system (i.e., an auxiliary component model obtained by modeling the auxiliary components). The auxiliary components may include a blower 1, a heat exchanger (which may include a first heat exchanger 6 and a second heat exchanger 7), and a burner 5.

[0086] Specifically, the fuel cell stack model can determine the total power output P of the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4. SOFC After modeling auxiliary components such as blower 1, the blower power P can be determined. blower It can be based on the total power generation P SOFC And blower power P blower The net AC power P of the system (i.e., the cascaded SOFC system) was determined. system,AC This allows us to determine the system electrical efficiency η under varying influence parameters. e Average net power P cell,net .

[0087] That is, the above target system model can also be understood as based on the system's net AC power P. system,AC And the different influencing parameters established, while the system's net AC power P system,AC Based on the total power generation P of the first-stage fuel cell stack and the second-stage fuel cell stack SOFC Blower power P blower This can be determined. The net AC power P under varying influence parameters can be determined or calculated using the target system model. system,AC This allows us to determine the system electrical efficiency η under varying influence parameters. e Average net power P cell,net .

[0088] In some embodiments, the total power generation P of the first-stage fuel cell stack and the second-stage fuel cell stack described above SOFC It can be determined using the following formula:

[0089] P SOFC =Max(V cell,1 j ,1 A cell,1 Ncell,1 +V cell,2 j ,2 A cell,2 N cell,2 (1)

[0090] Among them, P SOFC V represents the total power output of the first-stage and second-stage fuel cell stacks. cell,1 j1 is the single-cell output voltage of the first-stage fuel cell stack; j2 is the current density of the first-stage fuel cell stack; A cell,1 N represents the area of ​​a single battery cell in the first-stage fuel cell stack. cell,1 V represents the number of cells in a single first-stage fuel cell stack. cell,2 J is the single-cell output voltage of the second-stage fuel cell; J2 is the current density of the second-stage fuel cell; N cell,2 This represents the number of cells per cell in the second-stage stack; Max is the maximum value.

[0091] In some embodiments, the stack consists of multiple individual cells. The voltage of a single SOFC cell (i.e., the output voltage of a single stack cell mentioned above) can be calculated from the Nernst voltage and the activation loss, concentration loss, and ohmic loss, i.e.:

[0092] V cell =V Nernst -η act -η conc -η ohm (2)

[0093] Among them, Nernst voltage V Nernst It can be calculated using the following formula:

[0094]

[0095] Wherein, ΔG 0 denoted as Gibbs free energy change under standard conditions; F is the Faraday constant; R is the universal gas constant; n is the number of electrons participating in the reaction; These represent the mole fractions of hydrogen, oxygen, and water vapor on the electrode (anode or cathode) surface of the SOFC, respectively; p SOFC p0 and p10 represent the pressures under SOFC and standard conditions, respectively.

[0096] The above η act The activation overpotentials at the anode and cathode, representing activation losses, arise from the energy barriers that need to be overcome during the electrochemical reaction and can be obtained using the Butler-Volmer equation. η conc Concentration loss is caused by gas diffusion in the porous electrode. Since this embodiment uses an anode-supported SOFC, cathode concentration loss is ignored; therefore, η conc It can also be expressed as This is the anode concentration loss. η ohm This is an ohmic loss, caused by the influence of resistance during charge transport.

[0097] Specifically, the activation loss η mentioned above act Concentration loss η conc Ohmic loss η ohm They can be determined using the following formulas:

[0098]

[0099] η ohm =j.ASR ohm (6)

[0100] Where j is the current density; j0 is the exchange current density (which may include...). (These correspond to the anode exchange current density and the cathode exchange current density, respectively); For the limiting current density of the corresponding component, ASR ohm The ohmic surface resistance of the battery.

[0101] By adjusting the parameters in the SOFC single cell voltage formula, the obtained voltage fitting curve can be compared with the experimental data of multiple working conditions of industrial-sized batteries to obtain the minimum root mean square error. The relevant parameter values ​​required in the above formulas (4)-(6) can then be obtained, as shown in Table 2.

[0102] Table 2 Relevant parameter values

[0103]

[0104] In some embodiments, after determining the single-pile battery output voltage V cell,i After (which may include the single-cell output voltage of the first-stage stack and the single-cell output voltage of the second-stage stack), the total power generation P of the first-stage stack and the second-stage stack can be determined using the above formula (1). SOFC From determining the output voltage V of a single battery stack cell,i Then, determine the total power generation capacity P. SOFC The process is the process of fuel cell stack modeling, which ultimately yields a fuel cell stack model. Based on this model, the total power generation P of the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4 can be determined. SOFC .

[0105] V in the above formula (1) cell,1 j ,1 A cell,1 N cell,1 It can also be expressed as the single-stack output power of the first-stage fuel cell stack, as mentioned above, V. cell,2 j ,2 Acell,2 N cell,2 It can also be expressed as the single-stack output power of the second-stage stack. The output power of the stack in a cascaded SOFC system can be determined by the maximum module power under operating conditions, where the module is, for example,... Figure 3 The dashed box indicates the assembly of the fuel cell stack and related seals, circuits, and gas lines.

[0106] The above single-pile battery output voltage V cell,i It can be affected by the current density j (which may include the current density of the first-stage stack and the current density of the second-stage stack), and the average fuel flow rate Q of the i-th stage stack. i,fuel Operating voltage lower limit V lim Battery fuel utilization rate limit U f,lim The effects of, etc., can be expressed as:

[0107] V cell,i =V(j,Q) i,fuel V lim U f,lim …)(7)

[0108] Among them, the average fuel flow rate Q of the i-th stage stack i,fuel It can also be expressed as:

[0109]

[0110] Q 2,fuel =Q fuel *(1-U f,1 *R split (9)

[0111] Among them, Q 1,fuel Q represents the average fuel flow rate per unit cell of the first-stage fuel cell stack. fuel R is the average fuel flow rate per piece; CN R is the ratio of the number of cells in the first-stage fuel cell stack to the number of cells in the second-stage fuel cell stack. split The split ratio, used to characterize the opening degree of the fuel bypass valve; U f,1 This refers to the battery fuel utilization rate of the first-stage fuel cell stack.

[0112] Therefore, it can be seen that the output voltage V of a single battery stack cell,i The ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack can be controlled by R. CN The split ratio R, which characterizes the opening degree of the fuel bypass valve, split Average fuel flow rate per piece Q fuel Operating voltage lower limit V lim Battery fuel utilization rate limit U f,lim The effects of, etc.

[0113] In some embodiments, the net AC power of the above system is also determined according to the blower power corresponding to blower 1 in the air flow path (6) of the cascaded SOFC system. The blower 1 is used to pressurize the air in the air flow path (6) so that the pressurized air is delivered to the first stage stack 3 and the second stage stack 4.

[0114] Accordingly, the net AC power of the system in S202 above is determined at least based on the total power generation of the first-stage and second-stage fuel cell stacks, and in specific implementations, may include:

[0115] The net AC power of the system is determined based on the total power generation of the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4, and the power of the blower.

[0116] In some embodiments, the determination of the system's net AC power based on the total power generation of the first-stage fuel cell stack 3 and the second-stage fuel cell stack 4, and the blower power, may, in specific implementations, include:

[0117] The net AC power of the system is determined using the following formula:

[0118] P system,AC =P SOFC η DC / AC -P blower (10)

[0119] Among them, P system,AC P is the net AC power of the system. SOFC This refers to the total power output of the first and second stage fuel cell stacks (or the power output of the SOFC module); η DC / AC P represents the system's DC to AC conversion efficiency. blower This refers to the power of the blower (or the parasitic power of the system).

[0120] In some embodiments, since the system output power is related to the power generated by the SOFC module and the power consumption of the BOP auxiliary components, the net AC power P of the system is... system,AC It can be represented by the above formula (10).

[0121] In the airflow path (6) described above, the blower 1 is responsible for pressurizing and delivering the air required for the system's operation, and is the primary source of parasitic power loss in the system. The blower power can be determined using the following formula:

[0122]

[0123] Among them, P blower Q represents the power of the blower (or the parasitic power of the system). ria C is the molar flow rate of the blower. p,air T is the specific heat capacity of air at normal pressure.air,in η is the air inlet temperature of the blower. mec η is the mechanical efficiency of the blower. ise p represents the adiabatic efficiency of the blower. in p is the air inlet pressure of the blower. out γ is the air outlet pressure of the blower; γ is the specific heat ratio of air.

[0124] The above formula (11) can be used to model the auxiliary component blower 1 in the cascaded SOFC system.

[0125] In some embodiments, the above-mentioned calculation of the average net power per chip under changing influence parameters using a pre-established target system model may, in specific implementation, include:

[0126] Using the target system model, calculate the net AC power of the system under different influencing parameters;

[0127] Based on the net AC power, the average net power per cell under the changed influencing parameters is determined according to the following formula:

[0128]

[0129] Among them, P cell,net Net power per chip; N cell,1 N represents the number of cells in a single first-stage fuel cell stack. cell,2 P represents the number of cells per stack in the second-stage fuel cell stack. system,AC This represents the net AC power of the system.

[0130] In some embodiments, the system electrical efficiency can be determined according to the following formula:

[0131]

[0132] Where, η e P represents the system electrical efficiency. system,AC This represents the net AC power of the system. The amount of hydrogen consumed by the system (which can be calculated from the hydrogen (fuel) flow rate); The lower heating value of hydrogen (can be found in a table; this is known data).

[0133] Based on the above embodiments, the average fuel flow rate Q per piece can be obtained. fuel The ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack is R. CN The split ratio R, which characterizes the opening degree of the fuel bypass valve, split Operating voltage lower limit V lim Battery fuel utilization rate limit U f,lim Directly affects the output voltage V of a single battery stack cell,iThis, in turn, affects the total power generation P. SOFC This, in turn, affects the system's net AC power P. system,AC This indirectly affects the average net power per chip (P). cell,net and system electrical efficiency η e .

[0134] Therefore, it is possible to base it on the average fuel flow rate Q. fuel The number of batteries compared to R CN , Flow split ratio R split Operating voltage lower limit V lim Battery fuel utilization rate limit U f,lim Calculate the system electrical efficiency η e Net power per unit (P) cell,net The highest system electrical efficiency η is obtained. e By optimizing the corresponding design and operating parameters, the optimal cell number ratio and the optimal current shunt ratio can be determined, leading to the optimal structure of the cascaded SOFC system under different fuel flow rates or output power. The optimized cascaded SOFC system can generate electricity, provide heat, and supply water, featuring extremely high electrical efficiency, long stack safety and lifespan, a wide high-efficiency power range, strong fuel adaptability, and low-noise modularity. Furthermore, by combining the average fuel flow rate per cell and the average net power per cell, the initial and operating costs of the system can be adjusted to meet the needs of different application scenarios.

[0135] In some embodiments, auxiliary components in the cascaded SOFC system, such as burner 5 and heat exchanger, can also be modeled, as shown in the following formula:

[0136] Among them, burner 5 (burner 5 burns the remaining fuel in the exhaust gas of the second-stage fuel cell stack 4 and provides the high-temperature heat source required for heat exchanger heat exchange. Since the combustion of hydrogen and oxygen is rapid and relatively complete, it can be considered that a complete reaction occurs in the combustion chamber), the outlet gas temperature of burner 5 can be calculated according to the following formula (modeling process of burner 5):

[0137] h out =h ca,in +h an,in +q com ×δ com (14)

[0138] Among them, h out h is the enthalpy of the outlet gas of burner 5. ca,in and h an,in q represents the enthalpy of the gas from the cathode inlet and the gas from the anode inlet, respectively. com The heat generated by combustion; δ com This represents the heat transfer loss coefficient of burner 5. The enthalpy h of the gas mixture is also relevant. outSolve for the combustion chamber outlet gas temperature (e.g., set the iteration error as 10). -6 Then, iterative algorithms such as Newton's method and bisection method can be used to solve for the outlet gas temperature of burner 5. This method can be used to solve other enthalpy values ​​in the future (and will not be elaborated further).

[0139] The heat transfer loss parameters and combustion efficiency of burner 5 affect the exhaust gas temperature, which in turn affects the temperature (enthalpy) of each component and fluid in the cascaded SOFC system after equilibrium is reached, ultimately impacting the system's electrical efficiency. Therefore, the outlet gas temperature of burner 5 can be considered as a factor influencing the system's electrical efficiency, and the modeling results of the auxiliary component burner 5 can be taken into account when determining the optimal system electrical efficiency.

[0140] The method for calculating the gas temperature of the heat exchanger is as follows:

[0141]

[0142] Among them, h hot,out and h hot,in The enthalpy of the gas at the hot end outlet and the gas at the inlet of the heat exchanger, respectively, h cool,out and h cool,in η represents the enthalpy of the gas at the cold end outlet and the gas at the inlet of the heat exchanger, respectively. exch The heat exchange efficiency is given by the heat exchanger. The gas temperature of the heat exchanger can be obtained by solving for the enthalpy of the gas in the heat exchanger.

[0143] The parameters of the heat exchanger affect the temperature (enthalpy) of each component and fluid in a cascaded SOFC system, thus influencing the system's electrical efficiency. Therefore, the gas temperature of the heat exchanger can be considered as a factor affecting the system's electrical efficiency, and the modeling results of the auxiliary component heat exchanger can be taken into account when determining the optimal system electrical efficiency.

[0144] In some embodiments, the overall fuel efficiency of a cascaded SOFC system can also be calculated using the following formula:

[0145] U f,cascade =U f,1 +(1-U f,1 )×U f,2 (16)

[0146] Among them, U f,cascade U represents the system's total fuel efficiency; f,1 U represents the battery fuel utilization rate of the first-stage fuel cell stack. f,2 This refers to the battery fuel utilization rate of the second-stage fuel cell stack.

[0147] Calculating the overall fuel utilization rate of the system facilitates the analysis of the fuel utilization rate and distribution of the cascaded SOFC system.

[0148] In some embodiments, after screening the target influence parameters in step S203 above, the following may be included in the specific implementation:

[0149] Select the target battery number ratio and target current shunting ratio from the target impact parameters, and formulate an optimization scheme for the cascaded SOFC system based on the target battery number ratio and target current shunting ratio;

[0150] Based on the aforementioned cascaded SOFC system optimization scheme, the current cascaded SOFC system structure is optimized to obtain the optimized target cascaded SOFC system.

[0151] In some embodiments, the optimal average fuel flow rate per cell, optimal cell number ratio, optimal shunt ratio, optimal average fuel flow rate, optimal lower limit of operating voltage, and optimal upper limit of battery fuel utilization rate corresponding to the highest or ideal values ​​of system electrical efficiency and average net power per cell can be determined. An optimal combination of target influencing parameters can be first constructed, and then the optimal cell number ratio (as the target cell number ratio) and optimal shunt ratio (as the target shunt ratio) can be selected from this combination. Alternatively, the target cell number ratio and target shunt ratio can be directly selected from (multiple) target influencing parameters; this specification does not specifically limit this approach. Subsequently, based on the optimal cell number ratio and optimal shunt ratio, an optimization scheme for the cascaded SOFC system can be formulated to optimize the current cascaded SOFC system structure, thereby obtaining the optimized target cascaded SOFC system. Compared with existing technologies, this application can not only obtain the optimal impact parameters (target impact parameters) for cascaded SOFC systems, but also quantitatively compare the impact of different battery quantity ratios, shunt ratios, etc. on the performance of cascaded SOFC systems. This allows for the design of the optimal cascaded SOFC system structure, which can meet the needs of different application scenarios, effectively improve the electrical efficiency of cascaded SOFC systems, and reduce operating costs.

[0152] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. For details, please refer to the foregoing descriptions of the relevant processing embodiments; they will not be repeated here.

[0153] The foregoing description of this method is for illustrative purposes only and describes specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than those shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0154] Based on the above embodiments, this application can achieve the following beneficial effects:

[0155] (1) In a cascaded SOFC system, the unused fuel in the first stage is fully utilized in the second stage as anode exhaust gas, which greatly improves fuel utilization compared to traditional systems, thereby improving the system's electrical efficiency.

[0156] (2) The cell number ratio and shunt ratio are adjustable, maximizing the electrical efficiency of the cascaded system with the same number of cells. Since the second-stage stack utilizes at least part of the anode exhaust gas from the first-stage stack, the fuel quality is lower. A suitable cell number ratio and shunt ratio match the fuel flow rate and fuel quality of the first-stage and second-stage stacks, effectively maximizing the power generation performance of both stacks.

[0157] (3) Reduce the upper limit of battery fuel utilization rate to achieve safe and long-life stack and efficient system operation. After the first-stage stack generates electricity, the unused fuel enters the second-stage stack for full utilization. Therefore, the upper limit of battery fuel utilization rate can be reduced, and it is not necessary to pursue a very high single-stack fuel utilization rate in exchange for improved battery operating conditions.

[0158] (4) The system has good scalability and is suitable for SOFC systems with different power ranges. The fundamental reason for the relative improvement in the performance of cascaded SOFC systems lies in the full utilization of fuel, and secondly in the good and reasonable fuel distribution ratio between the first and second stage stacks. Therefore, as long as it is a multi-stack system, cascaded SOFC systems can significantly improve electrical efficiency compared with traditional systems.

[0159] (5) High-efficiency output at full power. The more efficient use of fuel in the cascaded SOFC system makes the electrical efficiency superior to that of traditional systems across the entire range of reasonable fuel flow. Therefore, the fuel flow can be relatively reduced at different system output power levels, resulting in high-efficiency power generation.

[0160] (6) The system has strong fuel adaptability. The cascade system is not limited by the type of fuel for more efficient use of fuel. With the right external reformer, hydrogen fuel, hydrocarbon fuel and ammonia fuel can all be used in this cascade SOFC system.

[0161] In a specific implementation scenario, a 10kW (multi-stack) cascaded SOFC system is optimized using hydrogen as fuel. In the system, fuel is heated by a second heat exchanger 7 before entering the fuel stacks. A fuel bypass valve 9 controls the ratio of fuel entering the first-stage stack 3 and the second-stage stack 4. The exhaust gas from the fuel anode of the first-stage stack 3 is reused in the second-stage stack 4, achieving full fuel utilization and significantly improving the system's electrical efficiency. This may include the following steps:

[0162] 1. Model each SOFC stack in the cascaded SOFC system.

[0163] For a detailed description of this step, please refer to the introduction of formulas (2)-(6) and formula (1), which will not be repeated here.

[0164] 2. Modeling auxiliary components in a cascaded SOFC system

[0165] For a detailed description of this step, please refer to the introduction of formulas (11), (14), and (15), which will not be repeated here.

[0166] 3. Optimize the design and operating parameters of the cascaded SOFC power generation system based on the target system model.

[0167] For a detailed description of this step, please refer to the introductions in S202 and S203, which will not be repeated here.

[0168] After identifying multiple target influencing parameters, recommended and unrecommended values ​​for each parameter can be obtained. Specifically, by controlling the shunt ratio to 1, the lower limit of the operating voltage to 0.7V, and the upper limit of the battery fuel utilization rate to 70%, when the average fuel flow rate per cell is between 0.2-0.6 L / min, the cascaded system's electrical efficiency and average power per cell can be well balanced, maintaining an electrical efficiency above 40% and an average power per cell above 20W. However, when the fuel flow rate exceeds 0.96 L / min, the average net power per cell decreases rapidly with the increase in parasitic power; therefore, further increasing the fuel flow rate is absolutely not recommended. Similarly, using the repeated control variable method, we can also obtain the following: when the battery ratio is 2-3, the system can maintain the optimal electrical efficiency range under the selected fuel flow rate, while when the battery ratio is <1, the electrical efficiency decreases significantly, so it is not recommended; under most system operating conditions, the system electrical efficiency is the highest when the shunt ratio is 1, that is, when all fuel is supplied to the first stage stack, so the bypass valve design can be eliminated in this embodiment; the lower limit of the operating voltage has a significant impact on the system performance under higher fuel flow rates, while the upper limit of battery fuel utilization rate has a significant impact on the system performance under lower fuel flow rates. Considering the combined impact of operating voltage and battery fuel utilization rate on the safe operation of SOFC, 0.7-0.75V and 70% are selected as recommended values, respectively.

[0169] Based on the optimization results, the optimized design scheme for a 10kW (multi-stacking) cascaded SOFC system can be selected as follows: Figure 4 As shown, in Figure 4 In this configuration, the first-stage fuel cell stack has 6 cells, the second-stage fuel cell stack has 3 cells, and the cell count ratio is 2. Figure 4 The design of the fuel bypass valve was eliminated.

[0170] The recommended and unrecommended values ​​for each objective's influencing parameter are shown in Table 3:

[0171] Table 3 Recommended and Unrecommended Values ​​for Target Influence Parameters

[0172]

[0173] Specifically, the recommended average fuel flow rate per cell is 0.2-0.6 L / min, and values ​​greater than 0.96 L / min are not recommended. A cell number ratio of less than 1 is not recommended. The lower limit of the operating voltage is 0.7V-0.75V, which is a recommended value. The upper limit of the battery fuel utilization rate is 70%, which is also a recommended value.

[0174] Although this specification provides the following examples or appendices Figure 5 The methods, steps, or apparatus structures shown may include more or fewer combined operational steps or module units based on conventional or non-inventive methods. In steps or structures where there is no logically necessary causal relationship, the execution order of these steps or the module structure of the apparatus is not limited to the execution order or module structure shown in the embodiments or drawings of this specification. When the methods or module structures described are applied in actual devices, servers, or terminal products, they can be executed sequentially or in parallel according to the methods or module structures shown in the embodiments or drawings (e.g., in parallel processor or multi-threaded processing environments, or even distributed processing or server cluster implementation environments). Based on the aforementioned method for optimizing the influence parameters of a cascaded SOFC system, this specification also proposes an embodiment of an influence parameter optimization device for a cascaded SOFC system, applied in a cascaded SOFC system. The cascaded SOFC system includes at least: a first-stage fuel stack fuel flow path, a second-stage fuel stack fuel flow path, and a first-stage fuel stack exhaust flow path. A fuel bypass valve and a first-stage fuel stack are sequentially connected along the first-stage fuel stack fuel flow path; a fuel bypass valve and a second-stage fuel stack are sequentially connected along the second-stage fuel flow path; and a first-stage fuel stack and a second-stage fuel stack are sequentially connected along the first-stage fuel stack exhaust flow path. The first-stage fuel stack and the second-stage fuel stack are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage fuel stack and the second-stage fuel stack. Figure 5 As shown, the device may specifically include the following modules:

[0175] The acquisition module 501 can be used to acquire the influence parameters of the cascaded SOFC system. The influence parameters include at least the ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack, and the shunt ratio characterizing the opening degree of the fuel bypass valve.

[0176] The calculation module 502 can be used to change the influencing parameters in sequence and calculate the system electrical efficiency and net power per unit under the changed influencing parameters using a pre-established target system model. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack.

[0177] The filtering module 503 can be used to filter target influence parameters from the changed influence parameters based on the calculated system electrical efficiency and net power per chip, wherein the system electrical efficiency and net power per chip corresponding to the target influence parameter are greater than the corresponding preset threshold.

[0178] In some embodiments, the influencing parameters in the acquisition module 501 may also include: average fuel flow rate per cell, lower limit of operating voltage, and upper limit of battery fuel utilization rate;

[0179] Accordingly, the above-mentioned calculation module 502 can also be used to use the control variable method to sequentially change the average fuel flow rate per cell, the number of cells, the current split ratio, the lower limit of the operating voltage, and the upper limit of the battery fuel utilization rate.

[0180] In some embodiments, the calculation module 502 described above can also be used to determine the total power generation of the first-stage stack and the second-stage stack according to the following formula:

[0181] P SOFC =Max(V cell,1 j ,1 A cell,1 N cell,1 +V cell,2 j ,2 A cell,2 N cell,2 )

[0182] Among them, P SOFC V represents the total power output of the first-stage and second-stage fuel cell stacks. cell,1 j1 is the single-cell output voltage of the first-stage fuel cell stack; j2 is the current density of the first-stage fuel cell stack; A cell,1 N represents the area of ​​a single battery cell in the first-stage stack. cell,1 V represents the number of cells in a single first-stage fuel cell stack. cell,2 J is the single-cell output voltage of the second-stage fuel cell stack; J2 is the current density of the second-stage fuel cell stack; N cell,2 This represents the number of cells per cell in the second-stage stack; Max is the maximum value.

[0183] In some embodiments, the net AC power of the system in the above-mentioned calculation module 502 is also determined according to the blower power corresponding to the blower in the air flow path of the cascaded SOFC system. The blower is used to pressurize the air in the air flow path so that the pressurized air is delivered to the first stage stack and the second stage stack.

[0184] Accordingly, the aforementioned calculation module 502 can also be used to determine the net AC power of the system based on the total power generation of the first-stage fuel cell stack and the second-stage fuel cell stack, and the power of the blower.

[0185] In some embodiments, the calculation module 502 described above can also be used to determine the net AC power of the system according to the following formula:

[0186] P system,AC =P SOFC η DC / AC -P blower

[0187] Among them, P system,AC P is the net AC power of the system. SOFC η represents the total power output of the first-stage and second-stage fuel cell stacks. DC / AC P represents the system's DC to AC conversion efficiency. blower This refers to the power of the blower.

[0188] In some embodiments, the calculation module 502 may further utilize the target system model to calculate the net AC power of the system under changed influence parameters; based on the net AC power, the average net power per unit area under changed influence parameters is determined according to the following formula:

[0189]

[0190] Among them, P cell,net Net power per chip; N cell,1 N represents the number of cells in a single first-stage fuel cell stack. cell,2 P represents the number of cells per stack in the second-stage fuel cell stack. system,AC This represents the net AC power of the system.

[0191] In some embodiments, the screening module 503 can be used to select the target battery number ratio and the target current shunting ratio from the target influence parameters, so as to formulate a cascaded SOFC system optimization scheme based on the target battery number ratio and the target current shunting ratio; and to optimize the current cascaded SOFC system structure based on the cascaded SOFC system optimization scheme to obtain the optimized target cascaded SOFC system.

[0192] As can be seen from the above, the influence parameter optimization device for a cascaded SOFC system provided in the embodiments of this specification can optimize the influence parameters of the cascaded SOFC system. Then, based on the optimized influence parameters (i.e. the target influence parameters mentioned above), the optimal cascaded SOFC system structure can be determined, thereby enabling the cascaded SOFC system to meet the needs of different application scenarios, effectively improving the electrical efficiency of the cascaded SOFC and reducing operating costs.

[0193] This specification also provides an electronic device based on the above-described method for optimizing the influence parameters of a cascaded SOFC system. The cascaded SOFC system includes at least: a first-stage fuel cell stack fuel flow path, a second-stage fuel cell stack fuel flow path, and a first-stage fuel cell stack exhaust flow path. A fuel bypass valve and a first-stage fuel cell stack are sequentially connected along the first-stage fuel cell stack fuel flow path; a fuel bypass valve and a second-stage fuel cell stack are sequentially connected along the second-stage fuel cell stack fuel flow path; and a first-stage fuel cell stack and a second-stage fuel cell stack are sequentially connected along the first-stage fuel cell stack exhaust flow path. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage fuel cell stack and the second-stage fuel cell stack. The device also includes a processor and a storage mechanism for processor-executable programs / instructions. The processor, in its specific implementation, can execute the following steps according to a program / instruction: acquire the impact parameters of the cascaded SOFC system, including at least the ratio of the number of cells in the first-stage and second-stage fuel cells, and the shunt ratio characterizing the opening of the fuel bypass valve; sequentially change the impact parameters, and using a pre-established target system model, calculate the system electrical efficiency and net power per cell under the changed impact parameters, wherein the target system model is established based on the system's net AC power, which is determined at least based on the total power generation of the first-stage and second-stage fuel cells; based on the calculated system electrical efficiency and net power per cell, select target impact parameters from the changed impact parameters, wherein the system electrical efficiency and net power per cell corresponding to the target impact parameters are greater than the corresponding preset thresholds.

[0194] To execute the above instructions more accurately, please refer to... Figure 6 As shown in the embodiments of this specification, another specific electronic device is also provided, wherein the electronic device includes a network communication port 601, a processor 602, and a memory 603. The above structures are connected by internal cables so that the various structures can perform specific data interaction.

[0195] Specifically, the network communication port 601 can be used to acquire the influence parameters of the cascaded SOFC system. The influence parameters include at least the ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack, and the shunt ratio characterizing the opening of the fuel bypass valve.

[0196] The processor 602 can be specifically used to sequentially change the influencing parameters, and use a pre-established target system model to calculate the system electrical efficiency and net power per unit under the changed influencing parameters. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack. Based on the calculated system electrical efficiency and net power per unit, target influencing parameters are selected from the changed influencing parameters. The system electrical efficiency and net power per unit corresponding to the target influencing parameters are greater than the corresponding preset threshold.

[0197] The memory 603 can be used to store the corresponding instruction program.

[0198] In this embodiment, the network communication port 601 can be a virtual port bound to different communication protocols, thereby enabling the sending or receiving of different data. For example, the network communication port can be a port responsible for web data communication, a port responsible for FTP data communication, or a port responsible for email data communication. Furthermore, the network communication port can also be a physical communication interface or communication chip. For example, it can be a wireless mobile network communication chip, such as GSM or CDMA; it can also be a Wi-Fi chip; or it can be a Bluetooth chip.

[0199] In this embodiment, the processor 602 can be implemented in any suitable manner. For example, the processor can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers, etc. This specification is not limiting.

[0200] In this embodiment, the memory 603 may include multiple layers. In a digital system, anything that can store binary data can be a memory. In an integrated circuit, a circuit with storage function but no physical form is also called a memory, such as RAM, FIFO, etc. In a system, a storage device with a physical form is also called a memory, such as a memory stick, TF card, etc.

[0201] This specification also provides a computer storage medium based on the above-described method for optimizing the influence parameters of a cascaded SOFC system. This medium is applied to a cascaded SOFC system, which includes at least: a first-stage fuel cell stack fuel flow path, a second-stage fuel cell stack fuel flow path, and a first-stage fuel cell stack exhaust flow path. A fuel bypass valve and a first-stage fuel cell stack are sequentially connected along the first-stage fuel cell stack fuel flow path; a fuel bypass valve and a second-stage fuel cell stack are sequentially connected along the second-stage fuel cell stack fuel flow path; and a first-stage fuel cell stack and a second-stage fuel cell stack are sequentially connected along the first-stage fuel cell stack exhaust flow path. The first-stage and second-stage fuel cell stacks are connected in series. The fuel bypass valve is used to adjust the proportion of fuel entering the first-stage and second-stage fuel cell stacks. The computer storage medium stores calculation data. The computer program / instruction, when executed, performs the following: acquiring the influence parameters of the cascaded SOFC system, the influence parameters including at least the ratio of the number of cells in the first-stage stack to the second-stage stack, and the shunt ratio characterizing the opening of the fuel bypass valve; sequentially changing the influence parameters, and using a pre-established target system model, calculating the system electrical efficiency and net power per cell under the changed influence parameters, the target system model being established based on the system's net AC power, which is determined at least based on the total power generation of the first-stage stack and the second-stage stack; and selecting target influence parameters from the changed influence parameters based on the calculated system electrical efficiency and net power per cell, the target influence parameters corresponding to which the system electrical efficiency and net power per cell are greater than the corresponding preset thresholds.

[0202] In this embodiment, the storage medium includes, but is not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), cache, hard disk drive (HDD), or memory card. The memory can be used to store computer program instructions. The network communication unit can be an interface configured according to standards specified in the communication protocol for network connection communication.

[0203] In this embodiment, the specific functions and effects implemented by the program instructions stored in the computer storage medium can be explained in comparison with other implementation methods, and will not be repeated here.

[0204] While this specification provides the steps of operation for the methods described in the embodiments or flowcharts, more or fewer steps may be included based on conventional or non-inventive means. The order of steps listed in the embodiments is merely one possible order of execution among many steps and does not represent the only possible order. In actual device or client product execution, the methods shown in the embodiments or drawings may be executed sequentially or in parallel (e.g., in a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, product, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitations, the presence of other identical or equivalent elements in a process, method, product, or apparatus that includes said elements is not excluded. The terms "first," "second," etc., are used to denote names and do not indicate any particular order.

[0205] Those skilled in the art will also know that, besides implementing the controller using purely computer-readable program code, the same functions can be achieved by logically programming the method steps, making the controller function as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices within it used to implement various functions can also be considered structures within that hardware component. Alternatively, the devices used to implement various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0206] This specification can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc., that perform a specific task or implement a specific abstract data type. This specification can also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0207] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this specification can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of this specification can essentially be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, mobile terminal, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments of this specification.

[0208] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. This specification can be used in numerous general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable electronic devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices, etc.

[0209] Although this specification has been described by way of examples, those skilled in the art will recognize that many variations of this specification are possible without departing from its spirit, and it is intended that the appended claims cover such variations without departing from the spirit of this specification.

Claims

1. A method for optimizing the influence parameters of a cascaded SOFC system, characterized in that, The application is in a cascaded SOFC system, which includes at least: a first-stage fuel flow path, a second-stage fuel flow path, and a first-stage fuel exhaust flow path. The method comprises: a fuel bypass valve and a first-stage fuel cell stack connected sequentially along the fuel flow path of the first-stage fuel cell stack; a fuel bypass valve and a second-stage fuel cell stack connected sequentially along the fuel flow path of the second-stage fuel cell stack; and a first-stage fuel cell stack and a second-stage fuel cell stack connected sequentially along the fuel exhaust flow path of the first-stage fuel cell stack. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage fuel cell stack and the second-stage fuel cell stack. Obtain the influence parameters of the cascaded SOFC system, including at least the ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack, and the shunt ratio characterizing the opening of the fuel bypass valve; By sequentially changing the influencing parameters, and using a pre-established target system model, the system electrical efficiency and net power per unit under the changed influencing parameters are calculated. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack. Based on the calculated system electrical efficiency and net power per chip, target influencing parameters are selected from the changed influencing parameters, wherein the system electrical efficiency and net power per chip corresponding to the target influencing parameters are greater than the corresponding preset threshold.

2. The method according to claim 1, characterized in that, The influencing parameters also include: average fuel flow per cell, lower limit of operating voltage, and upper limit of battery fuel utilization rate; Accordingly, the sequential changing of the influencing parameters includes: Using the controlled variable method, the average fuel flow rate per cell, the ratio of the number of cells, the current split ratio, the lower limit of the operating voltage, and the upper limit of the battery fuel utilization rate are changed sequentially.

3. The method according to claim 1, characterized in that, The total power output of the first-stage fuel cell stack and the second-stage fuel cell stack is determined according to the following formula: P SOFC <Max(V cell,1 j ,1 HAS cell,1 N cell,1 +V cell,2 j ,2 HAS cell,2 N cell,2 ) Among them, P SOFC V represents the total power output of the first-stage and second-stage fuel cell stacks. cell,1 j1 is the single-cell output voltage of the first-stage fuel cell stack; j2 is the current density of the first-stage fuel cell stack; A cell,1 N represents the area of ​​a single battery cell in the first-stage fuel cell stack. cell,1 V represents the number of cells in a single first-stage fuel cell stack. cell,2 J is the single-cell output voltage of the second-stage fuel cell; J2 is the current density of the second-stage fuel cell; N cell,2 This represents the number of cells per cell in the second-stage stack; Max is the maximum value.

4. The method according to claim 1, characterized in that, The net AC power of the system is also determined based on the blower power corresponding to the blower in the air flow path of the cascaded SOFC system. The blower is used to pressurize the air in the air flow path so that the pressurized air is delivered to the first stage fuel cell stack and the second stage fuel cell stack. Accordingly, the net AC power of the system is determined at least based on the total power generation of the first-stage and second-stage fuel cell stacks, including: The net AC power of the system is determined based on the total power output of the first-stage and second-stage fuel cell stacks and the power output of the blower.

5. The method according to claim 4, characterized in that, The determination of the system's net AC power based on the total power generation of the first-stage and second-stage fuel cell stacks and the blower power includes: The net AC power of the system is determined using the following formula: P system,AC =P SOFC the DC / AC -P blower Among them, P system,AC P is the net AC power of the system. SOFC η represents the total power output of the first-stage and second-stage fuel cell stacks. DC / AC P represents the system's DC to AC conversion efficiency. blower This refers to the power of the blower.

6. The method according to claim 1, characterized in that, The calculation of average net power per chip under varying influencing parameters using a pre-established target system model includes: Using the target system model, calculate the net AC power of the system under different influencing parameters; Based on the net AC power, the average net power per cell under the changed influencing parameters is determined according to the following formula: Among them, P cell,net Net power per chip; N cell,1 N represents the number of cells in a single first-stage fuel cell stack. cell,2 P represents the number of cells per stack in the second-stage fuel cell stack. system,AC This represents the net AC power of the system.

7. The method according to claim 1, characterized in that, The method further includes: Select the target battery number ratio and target current shunting ratio from the target impact parameters, and formulate an optimization scheme for the cascaded SOFC system based on the target battery number ratio and target current shunting ratio; Based on the aforementioned cascaded SOFC system optimization scheme, the current cascaded SOFC system structure is optimized to obtain the optimized target cascaded SOFC system.

8. A cascaded SOFC system, characterized in that, At least including: First-stage fuel flow path, second-stage fuel flow path, first-stage fuel exhaust flow path; The first-stage fuel cell stack is connected in sequence along the fuel flow path of the first-stage fuel cell stack, and the second-stage fuel cell stack is connected in sequence along the fuel flow path of the second-stage fuel cell stack. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in sequence along the fuel exhaust flow path of the first-stage fuel cell stack. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in series. The fuel bypass valve is used to adjust the ratio of fuel entering the first-stage fuel cell stack and the second-stage fuel cell stack.

9. A device for optimizing the influence parameters of a cascaded SOFC system, characterized in that, The application is in a cascaded SOFC system, which includes at least: a first-stage fuel flow path, a second-stage fuel flow path, and a first-stage fuel exhaust flow path. The device comprises: a fuel bypass valve and a first-stage fuel cell stack connected sequentially along the fuel flow path of the first-stage fuel cell stack; a fuel bypass valve and a second-stage fuel cell stack connected sequentially along the fuel flow path of the second-stage fuel cell stack; and a first-stage fuel cell stack and a second-stage fuel cell stack connected sequentially along the fuel exhaust flow path of the first-stage fuel cell stack. The first-stage fuel cell stack and the second-stage fuel cell stack are connected in series. The fuel bypass valve is used to adjust the fuel ratio entering the first-stage fuel cell stack and the second-stage fuel cell stack. The device includes: The acquisition module is used to acquire the influence parameters of the cascaded SOFC system. The influence parameters include at least the ratio of the number of cells in the first-stage stack to the number of cells in the second-stage stack, and the shunt ratio characterizing the opening degree of the fuel bypass valve. The calculation module is used to change the influencing parameters in sequence and calculate the system electrical efficiency and net power per unit under the changed influencing parameters using a pre-established target system model. The target system model is established based on the net AC power of the system, and the net AC power of the system is determined at least based on the total power generation of the first-stage stack and the second-stage stack. The filtering module is used to filter target impact parameters from the changed impact parameters based on the calculated system electrical efficiency and net power per chip, wherein the system electrical efficiency and net power per chip corresponding to the target impact parameters are greater than the corresponding preset threshold.

10. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1 to 7.

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