A SOFC stack and its method of startup and shutdown

Abstract

The present invention provides a SOFC stack and a method for starting and shutting down the same, including a heating module, a stack core, a reforming module, an exhaust gas treatment module, a cooling module, and a heat insulation module; the heating module is used to heat the stack core and the cathode gas; the cathode gas is fed into the stack core for cathode reaction; electrochemical reaction occurs in the stack core to output electric energy outward; the electrochemical reaction includes a cathode reaction and an anode reaction; cathode exhaust gas is generated after the cathode reaction, and the cathode exhaust gas supplies heat to the reforming module; the reforming module is used to gasify and reform the reforming fuel into hydrogen-rich gas; the hydrogen-rich gas is fed into the stack core for anode reaction; the exhaust gas treatment module is used to treat the cathode exhaust gas and the anode exhaust gas and supply heat outward; the cooling module is used to cool the cold end of the stack core; the heat insulation module is used to prevent heat dissipation inside the stack; the heating efficiency of the SOFC stack is improved, and the heat insulation effect is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of battery stacks, and in particular to a SOFC battery stack and a method for starting and shutting down the stack. Background Art

[0002] Fuel cells are an efficient and clean power generation technology that directly converts the chemical energy of fuel into electrical energy without going through the combustion process. The entire power generation process has the advantages of no pollution, zero emissions, and high power generation efficiency. High-temperature solid oxide fuel cells (SOFC) have an operating temperature of 600℃~1000℃, diversified fuel sources, high power generation efficiency, and high thermal quality, and are suitable for a variety of application scenarios. SOFC batteries have an operating temperature of 600℃~1000℃ and need to be heated before working. At present, SOFC fuel cell stack heating is achieved by heating the cathode gas and anode gas. The overheated cathode gas and anode gas are passed into the stack to preheat and heat them. The anode and cathode gases after the stack are burned and released heat to heat the anode and cathode gases and other components of the system. This heating method has low heating efficiency, complex system structure, and difficulty in heat preservation. Secondly, the various components of the SOFC stack are loosely arranged, and connecting them through pipes will cause a large amount of heat loss, making assembly difficult.

[0003] In view of this, this specification proposes a SOFC stack and a method for starting and shutting down the stack to improve the heating efficiency of the SOFC stack, make the stack structure simpler, enhance thermal insulation, use highly integrated modules, and simplify assembly difficulty. Summary of the invention

[0004] The object of the present invention is to provide a SOFC stack, comprising a heating module, a core, a reforming module, a tail gas treatment module, a cooling module and a thermal insulation module; the heating module is used to heat the core and cathode gas; the cathode gas is fed into the core to perform a cathode reaction; an electrochemical reaction is performed in the core to output electrical energy to the outside; the electrochemical reaction includes the cathode reaction and the anode reaction; a cathode tail gas is generated after the cathode reaction, and the cathode tail gas provides heat for the reforming module; the reforming module is used to gasify and reform the reforming fuel into hydrogen-rich gas; the hydrogen-rich gas is fed into the core to perform an anode reaction; the tail gas treatment module is used to treat the cathode tail gas and the anode tail gas, and to supply heat to the outside; the cooling module is used to cool the cold end of the core; the thermal insulation module is used to prevent heat loss in the stack.

[0005] Further, the heating module includes a heating unit, a heating block, a heat conducting block, and an air preheating unit; the heating unit is used to generate heat; the heating block is arranged between the heating unit and the core to uniformly heat the core; the heat conducting block is used to conduct the heat of the heating block to the core; the air preheating unit is used to heat the cathode gas.

[0006] Further, the air preheating unit includes an air preheating sub-unit and an air distribution sub-unit; the air preheating sub-unit is arranged between the heating unit and the heating block and is used to heat the cathode gas by using the heat generated by the heating unit; the air distribution sub-unit is used to distribute the heated cathode gas to the core.

[0007] Further, the heating unit is an infrared combustion heating furnace or an electric heater.

[0008] Further, the tail gas treatment module includes a tail gas treatment unit, an anode tail gas dehydration unit of the fuel cell stack, a cathode tail gas inlet of the fuel cell stack, an anode tail gas inlet of the fuel cell stack, a tail gas treatment outlet, and a heat recovery unit; the anode tail gas inlet of the fuel cell stack is used to send the anode tail gas into the anode tail gas dehydration unit of the fuel cell stack; the anode tail gas dehydration unit of the fuel cell stack is used to dehydrate the anode tail gas and send the dehydrated anode tail gas into the tail gas treatment unit, and a check valve is arranged between the anode tail gas dehydration unit of the fuel cell stack and the tail gas treatment unit; the cathode tail gas inlet of the fuel cell stack is used to send the cathode tail gas into the tail gas treatment unit; the tail gas treatment unit is used to allow the dehydrated anode tail gas and the cathode tail gas to react and release heat; the tail gas outlet is used to discharge the tail gas generated after the reaction of the dehydrated anode tail gas and the cathode tail gas; the heat recovery unit is used to recover the heat generated by the reaction of the dehydrated anode tail gas and the cathode tail gas and supply heat outward.

[0009] Further, the cooling module is a cooling block and / or a cooling channel; the cooling block is arranged at the upper and lower ends of the grid plate of the core; the cooling channel is arranged in the middle of the grid plate of the core.

[0010] Further, a housing is further included, and the heating module, the core, the reformer, the tail gas treatment module, and the cooling module are arranged inside the housing, and heat insulation materials are arranged between each module and the inner surface of the housing.

[0011] Further, the reforming module is arranged inside or outside the fuel cell stack; it includes a reforming fuel gasification unit and a reformer; the reforming fuel gasification unit is used to gasify the liquid reforming fuel; the reformer is used to reform the gasified reforming fuel into hydrogen-rich gas.

[0012] The object of the present invention is to provide a method for starting an SOFC stack, the method applying the SOFC stack described in any one of the above, including turning on the combustion blower to purge and heat the module; after purging for a preset purging time, turning on the heating fuel switch valve to add heating fuel and performing automatic ignition; judging whether the ignition is successful; if the ignition is successful, adjusting the combustion parameters and judging whether the heating parameters are within the preset heating temperature range; if the heating parameters are within the preset heating temperature range, maintaining the heating parameters, monitoring the combustion state of the heating module, and judging whether it goes out; if it goes out, judging whether other components are turned on; if all other components are turned on, executing an emergency stop or one-key shutdown command; if there are unturned-on other components, closing the heating fuel switch valve and the combustion blower and giving an alarm prompt; if it does not go out, maintaining the combustion parameters, where the maintaining of the combustion parameters includes the cold end temperature, reformer temperature, stack temperature, and water heater temperature; judging whether the cold end temperature is greater than or equal to the maximum cold end temperature; if so, using cooling water within a preset temperature range to cool the cold end; judging whether the reformer temperature is greater than or equal to the minimum reformer temperature; if so, turning on the reforming fuel pump to raise the reformer temperature to the preset reforming temperature range and maintaining the reformer temperature within the preset reforming range; judging whether the stack temperature is greater than or equal to the minimum stack temperature; if so, turning on the cathode blower to raise the stack temperature to the preset stack temperature range and maintaining the stack temperature within the preset stack temperature range; judging whether the water heater temperature is greater than or equal to the minimum water heater temperature; if so, turning on the hot water inlet switch; if the heating parameters are not within the preset heating temperature range, adjusting the intake of the combustion blower and the heating fuel; if the ignition is not successful, repeating the ignition and judging the ignition state; if the ignition state shows that the ignition is successful, adjusting the combustion parameters and performing subsequent steps; if the ignition state shows that the ignition is not successful, closing the heating fuel switch valve and the combustion blower and giving an alarm prompt.

[0013] Further, the execution of the emergency stop or one-key shutdown command includes gradually decreasing the reforming fuel, cathode blower, and combustion blower to their respective preset values and closing the water heater inlet switch; judging whether the temperature at the cooling water outlet is less than or equal to the preset shutdown cooling temperature, judging whether the stack temperature is less than or equal to the preset stack shutdown temperature, and judging whether the reformer temperature is within the preset shutdown reforming temperature range; if all are yes, closing the heating fuel switch valve, closing the circulation pump, closing the cooling fan, closing the heating fan, and closing the reforming fuel pump.

[0014] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0015] In some embodiments of this specification, the stack components are modularly connected and highly integrated. With the assistance of thermal insulation materials, they are placed in a housing, reducing the heat dissipation path of the stack components and improving the comprehensive utilization efficiency of the battery.

[0016] In some embodiments of this specification, through modular components, the interchangeability and standardization of the stack components are improved, and the maintenance cost of stack operation is reduced.

[0017] In some embodiments of this specification, by arranging an infrared energy-saving burner and / or an electric heater below the stack core, and quickly transferring the heat to the core reaction area of the stack through a heating block and a heat conduction block, and using a cathode fan to assist in heating and balance the reaction temperature of the stack with high-temperature air, the core reaction temperature distribution of the stack is made uniform and the combustion is more complete. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 An exemplary module diagram of a SOFC stack provided for some embodiments of the present invention;

[0019] Figure 2 An exemplary schematic diagram of the housing of the SOFC stack provided for some embodiments of the present invention;

[0020] Figure 3 An exemplary flowchart for starting the SOFC stack provided for some embodiments of the present invention;

[0021] Figure 4 An exemplary flowchart for emergency stop or one-key shutdown of the SOFC stack provided for some embodiments of the present invention;

[0022] Reference numerals: 101 - stack core, 102 - heat conduction block, 103 - reformed fuel gasification unit, 104 - reformer, 105 - cooling module, 106 - housing, 107 - heating block, 108 - air preheating unit, 109 - thermal insulation module, 110 - heating unit, 111 - stack anode tail gas dehydration unit, 112 - tail gas treatment module, 113 - tail gas treatment outlet, 201 - water outlet of the tail gas treatment module, 202 - pipeline connecting the tail gas treatment module and the anode of the stack, 203 - cooling water inlet and outlet, 204 - combustion mixer, 205 - water inlet of the tail gas treatment module, 206 - reformed fuel inlet, 207 - combustion fan. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0024] Figure 1 An exemplary module diagram of a SOFC stack provided for some embodiments of the present invention. As Figure 1 shown, the stack 100 may include a heating module, a stack core 101, a reforming module, an exhaust gas treatment module 112, a cooling module 105, and a heat insulation module 109.

[0025] The heating module is used to heat the stack core and the cathode gas; the cathode gas is sent into the stack core for the cathode reaction.

[0026] The stack core 101 is the core component of the SOFC stack, including units such as cells, grid plates, and grid plate covers. The cells in the stack core can be connected in series and / or in parallel to meet different output requirements. The cells can also include single-layer cells and / or multi-layer cells. In some embodiments, the stack core 101 can be a flat tube type cell core.

[0027] In some embodiments, the heating module includes a heating unit 110, a heating block 107, a heat conducting block 102, and an air preheating unit 108.

[0028] The heating unit 110 is used to generate heat. For example, the heating unit 110 can be an infrared combustion heating furnace or an electric heater. The heating unit can be arranged directly above, directly below, or in the middle of the stack core reaction area (such as in the middle of the cells). The infrared combustion heating furnace can include metal fiber infrared combustion, ceramic burner head infrared combustion, catalytic combustion, etc.

[0029] The heating block 107 is arranged between the heating unit 110 and the stack core 101 to uniformly heat the stack core 101 to prevent local overheating from affecting the performance of the cells.

[0030] The heat conducting block 102 is used to conduct the heat of the heating block 107 to the stack core. In some embodiments, the heat conducting block 102 can be a multi-layer cell heat conducting block. The heating block transfers heat to the heat conducting block 102 to heat the core reaction area of the stack.

[0031] The air preheating unit 108 is used to heat the cathode gas, and then directly input the heated high-temperature cathode gas into the core area of the stack core for the cathode reaction. In some embodiments, the air preheating unit includes an air preheating sub-unit and an air distribution sub-unit; the air preheating sub-unit is arranged between the heating unit and the heating block and is used to heat the cathode gas using the heat generated by the heating unit; the air distribution sub-unit can be arranged on the upper side of the heating block and the lower side of the core reaction area of the stack core to distribute the heated cathode gas to the stack core.

[0032] In some embodiments, the heating module 110 can be fixedly connected to the stack core 101 by bolts.

[0033] An electrochemical reaction is carried out in the core 101 to output electrical energy to the outside; the electrochemical reaction includes a cathode reaction and an anode reaction; a cathode tail gas is generated after the cathode reaction, and the cathode tail gas provides heat for the reforming module.

[0034] The reforming module is used to gasify and reform the reforming fuel into hydrogen-rich gas; the hydrogen-rich gas is sent to the core for anode reaction. The reforming module is fixedly connected to the exhaust manifold, and the cathode tail gas enters the exhaust manifold to heat the reforming fuel in the reforming module to achieve gasification reforming of the reforming fuel and maintain the reforming reaction conditions.

[0035] The reforming module is arranged inside or outside the stack; it includes a reforming fuel gasification unit 103 and a reformer 104; the reforming fuel gasification unit 103 is used to gasify the liquid reforming fuel; the reformer 104 is used to reform the gasified reforming fuel into hydrogen-rich gas; the outlet of the reformer is connected to the core anode inlet. In some embodiments, the reforming fuel can be methanol water.

[0036] The tail gas treatment module 112 is used to treat cathode tail gas and anode tail gas and to supply heat to the outside. In some embodiments, the core 101 is connected to the tail gas treatment module 112 via a pipeline.

[0037] In some embodiments, the tail gas treatment module includes a tail gas treatment unit, anode tail gas dehydration unit 111, cathode tail gas inlet, anode tail gas inlet, tail gas treatment outlet 113 and a heat recovery unit. The anode tail gas inlet of the stack is used to send the anode tail gas to the anode tail gas dehydration unit of the stack; the anode tail gas dehydration unit of the stack is used to dehydrate the anode tail gas and send the dehydrated anode tail gas to the tail gas treatment unit, a check valve is arranged between the anode tail gas dehydration unit of the stack and the tail gas treatment unit, the core anode outlet is connected to the inlet of the anode tail gas dehydration unit of the stack, and the outlet of the anode tail gas dehydration unit of the stack is connected to the inlet of the tail gas treatment unit; the cathode tail gas inlet of the stack is used to send the cathode tail gas to the tail gas treatment unit; the tail gas treatment unit is used to supply the dehydrated anode tail gas and cathode tail gas for catalytic combustion reaction and heat release; the tail gas outlet is used to discharge the tail gas generated after the reaction of the dehydrated anode tail gas and cathode tail gas; the heat recovery unit is used to recover the heat generated by the reaction of the dehydrated anode tail gas and cathode tail gas, and supply heat to the outside. For example, the heat recovery unit may be a water heater, which heats cold water by providing a heat exchange channel to output hot water.

[0038] The cooling module 105 is used to cool the cold end of the core. The cold end of the core may be a portion of the core that needs to be maintained at a lower temperature. For example, the cold end of the core may include the upper and lower ends of the grid plate of the core and the middle of the grid plate of the core. The temperature of the cold end may be maintained below 100°C. In some embodiments, the cooling module may be a cooling block and / or a cooling channel; the cooling block is disposed at the upper and lower ends of the grid plate of the core; the cooling channel is disposed in the middle of the grid plate of the core, and is used for sealing and cooling the cold end of the core.

[0039] The heat insulation module 109 is used to prevent heat dissipation in the fuel cell stack. For example, the heat insulation module 109 can be arranged around the heating module 110, the stack core 101, the reforming module, the tail gas treatment module 112 and the cooling module 105 to prevent heat dissipation.

[0040] In some embodiments, the fuel cell stack may further include a housing 106. The heating module 110, the stack core 101, the reforming module, the tail gas treatment module 112 and the cooling module 105 can be arranged inside the housing 106, and heat insulation materials are arranged between each module and the inner surface of the housing. In some embodiments, the thickness of the heat insulation materials can be 60 - 100 mm.

[0041] In some embodiments of this specification, the SOFC fuel cell stack integrates functional modules such as a modular stack core, a heating module, a reformer and a tail gas treatment module through threads and pipes, so as to be highly integrated. For example, the heating module is integrated with the formed heat insulation module and is bolted to the stack core. The reformer and the exhaust passage are bolted and integrated with the stack core. The cathode tail gas outlet of the stack core is connected to the inlet of the tail gas treatment module through a pipe, and the anode tail gas is connected to the inlet of the tail gas treatment module through a one-way valve of a dehydrating pipe in the anode tail gas dehydration unit through a pipe. The cathode and anode tail gases are catalytically combusted after being mixed in the tail gas treatment module, heating cold water and outputting hot water outward. This enables each module to be connected through corresponding interfaces, and each module can be independently replaced, improving the interchangeability and standardization of the fuel cell stack components and saving costs. At the same time, the highly modular integration also reduces the heat loss between components, improving the heat utilization efficiency and the overall efficiency of the system.

[0042] In some embodiments of this specification, by directly heating the fuel cell stack using the heating module, the heating efficiency is improved, enabling the fuel cell stack to be quickly started. And the high-temperature tail gas generated by the cathode reaction provides heat for gasification reforming, enabling the further improvement of the energy utilization efficiency.

[0043] Figure 2 It is an exemplary schematic diagram of the housing of the SOFC fuel cell stack provided by some embodiments of the present invention. As Figure 2 shown, the housing 106 can include an upper housing and a lower housing.

[0044] In some embodiments, a gasket is arranged between the upper housing and the lower housing, and the upper housing and the lower housing are connected by bolts. A plurality of interfaces are also arranged on the housing to support the reaction of the SOFC fuel cell stack.

[0045] Specifically, a combustion mixer 204, a combustion blower 207, a fuel inlet, a cathode blower connected to the cathode of the fuel cell stack, an anode tail gas dehydration unit 111 connected to the anode of the fuel cell stack, a methanol-water inlet 206 connected to the reformer, a water outlet 201 and a water inlet 205 connected to the tail gas treatment module, a pipeline 202 connecting the tail gas treatment module and the anode of the fuel cell stack, and a cooling water inlet and outlet 203 connected to the cooling module, a fuel cell stack output connection port and a temperature detection interface are provided on the housing.

[0046] When the SOFC fuel cell stack operates, fuel can be input into the fuel mixer through the fuel inlet. After the fuel mixer mixes the fuel, the fuel is sent into the combustion furnace body for combustion to supply heat to the fuel cell stack through combustion heating. The cathode blower can supply heat for the cathode reaction to maintain the temperature T50 of the fuel cell stack within the range of 650°C ≤ T50 ≤ 800°C. Methanol-water can enter the reformer through the methanol-water inlet for reforming. Cold water can be input into the tail gas treatment module through the water inlet of the tail gas treatment module, and then the cold water is heated through the heat exchange channel, and the hot water is output through the water outlet of the tail gas treatment module. The cooling water inlet and outlet connected to the cooling module can be used to maintain the cold end temperature of the stack core below 100°C.

[0047] Figure 3 FIG. 300 is an exemplary flowchart for starting an SOFC fuel cell stack provided by some embodiments of the present invention. In some embodiments, process 300 can be executed by fuel cell stack 100. As Figure 3 shown, process 300 may include the following:

[0048] In some embodiments, a start key can be provided on the fuel cell stack, and the fuel cell stack can be started with one key through the start key.

[0049] After starting the fuel cell stack, start the combustion blower to purge the heating module to provide sufficient oxygen for subsequent combustion reactions. The combustion blower can also be a heating blower.

[0050] After purging for a preset purge time, open the heating fuel switch valve to add heating fuel and perform automatic ignition. The preset purge time can refer to the minimum time length preset for the combustion blower to purge the heating module when the fuel cell stack is started. In some embodiments, the preset purge time can be greater than or equal to 15 s.

[0051] Judge whether the ignition is successful.

[0052] If the ignition is successful, adjust the combustion parameters and judge whether the heating parameters are within the preset heating temperature range. The combustion parameters can include the heating parameters. The preset heating temperature can refer to the temperature of the heating fuel preset in advance. For example, the range of the preset heating temperature T1 can be 860°C ≤ T1 ≤ 900°C.

[0053] If the heating parameter is within the preset heating temperature range, maintain the heating parameter, monitor the combustion state of the heating module, and determine whether it goes out of flame.

[0054] If it goes out of flame, determine whether other components are turned on; other components may include a circulation pump, a cooling fan, a methanol water pump, etc.

[0055] If all other components are turned on, execute an emergency stop or one-key shutdown command; all other components being turned on means that other components are turned on at the opening time.

[0056] If there are still components that are not turned on when other components reach the opening time, close the heating fuel switch valve and the combustion fan, and give an alarm prompt.

[0057] If it does not go out of flame, maintain the combustion parameters, and the combustion parameters include the cold end temperature T10, the reformer temperature T20, the stack temperature T40, and the water heater temperature T30. In some embodiments, the combustion parameters can be obtained through temperature sensors.

[0058] Determine whether the cold end temperature T10 is greater than or equal to the minimum cold end temperature; if so, use cooling water within the preset temperature range to cool the cold end. The minimum cold end temperature may refer to the maximum temperature that the cold end temperature should be lower than as pre-set. The maximum cold end temperature can be set according to the material of the cold end. For example, the cold end of the core is sealed with sealant, and the maximum cold end temperature can be 100°C. When the cold end temperature T10 is greater than or equal to 100°C, turn on the circulation pump to circulate the cooling water of the cooling module, and monitor the temperature T60 at the cooling water inlet. When the temperature T60 at the cooling water inlet is greater than or equal to 80°C, turn on the cooling fan to cool the cooling water, so that the temperature T60 at the cooling water inlet is maintained at about 85°C, with an error of 5°C.

[0059] Determine whether the reformer temperature is greater than or equal to the minimum reformer temperature; if so, turn on the reforming fuel pump, raise the reformer temperature to the preset reforming temperature range, and maintain the reformer temperature within the preset reforming range. The minimum reformer temperature may refer to the lowest temperature at which the reforming fuel pump is pre-set to be turned on. In some embodiments, the minimum reformer temperature can be 230°C. When the reformer temperature T20 ≥ 230°C, turn on the reforming fuel pump to gradually increase the reforming temperature to the reforming temperature (e.g., the temperature for reforming methanol water). The preset reforming range may refer to the temperature range for reforming fuel pre-set. In some embodiments, the object of reforming can be methanol water, and the reforming temperature can be between 230°C and 280°C.

[0060] Determine whether the stack temperature is greater than or equal to the minimum stack temperature; if so, turn on the cathode fan, raise the stack temperature to the preset stack temperature range, and maintain the fuel cell stack temperature within the preset stack temperature range. The minimum stack temperature can refer to the lowest stack temperature at which the cathode fan is turned on. When the stack temperature T40 ≥ 600 °C, turn on the cathode fan of the stack and gradually increase the stack temperature to the stack reaction temperature. The preset stack temperature range can refer to the temperature range in which the stack reacts. In some embodiments, the preset stack temperature range T50 can be 650 °C ≤ T50 ≤ 800 °C to maintain the fuel cell stack temperature within the preset stack temperature range.

[0061] Determine whether the water heater temperature T30 is greater than or equal to the minimum water heater temperature; if so, turn on the hot water inlet switch. The water heater can be implemented through an exhaust gas treatment module. By inputting cold water into the exhaust gas treatment module, the exhaust gas treatment module outputs hot water. The minimum water heater temperature can refer to the lowest temperature at which hot water is output pre-set. In some embodiments, the minimum water heater temperature can be 90 °C. When the water heater temperature T30 ≥ 90 °C, turn on the hot water inlet switch to provide hot water.

[0062] If the heating parameter is not within the preset heating temperature range, adjust the intake of the combustion fan and the heating fuel.

[0063] If the ignition is unsuccessful, repeat the ignition and judge the ignition status.

[0064] If the ignition status shows that the ignition is successful, adjust the combustion parameters and perform subsequent steps.

[0065] If the ignition status shows that the ignition is unsuccessful, close the heating fuel switch valve and the combustion fan and give an alarm prompt.

[0066] Figure 4 This is an exemplary flowchart for shutting down the SOFC stack provided by some embodiments of the present invention. In some embodiments, process 400 can be executed by stack 100. As Figure 3 shown, process 400 can include the following:

[0067] When the stack encounters an emergency and needs to shut down or shuts down normally, the one-key shutdown method can be executed. A shutdown button can be set on the housing, and the user can achieve one-key shutdown of the stack through the shutdown button.

[0068] When receiving the one-key shutdown instruction, gradually decrease the reforming fuel, the air volume of the cathode fan, and the air volume of the combustion fan to their respective preset values, and close the hot water inlet switch.

[0069] Judge whether the temperature T70 of the cooling water outlet is less than or equal to the preset shutdown cooling temperature, whether the temperature T50 of the fuel cell stack is less than or equal to the preset fuel cell stack shutdown temperature, and whether the temperature T20 of the reformer is within the preset shutdown reforming temperature range. The preset shutdown cooling temperature may refer to the maximum value of the temperature of the cooling water outlet in the cooling module during shutdown set in advance. In some embodiments, the preset shutdown cooling temperature may be 55 °C. The preset fuel cell stack shutdown temperature may refer to the highest temperature of the fuel cell stack during shutdown set in advance. In some embodiments, the preset fuel cell stack shutdown temperature may be 400 °C. The preset shutdown reforming temperature range may refer to the temperature range of the reforming temperature during shutdown set in advance. In some embodiments, the preset shutdown reforming temperature range T20 may be 180 °C ≤ T20 ≤ 240 °C.

[0070] If all are, then close the heating fuel switch valve, close the circulation pump, close the cooling fan, close the heating fan, and close the reforming fuel pump. For example, when the cooling water outlet temperature T70 ≤ 50 °C, the fuel cell stack temperature T50 ≤ 400 °C, and the reformer temperature 180 °C ≤ T20 ≤ 240 °C, close the heating fuel switch valve, close the circulation pump, close the cooling fan, close the heating fan, and close the reforming fuel pump to achieve shutdown.

[0071] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A SOFC stack, characterized in that, it includes a heating module, a stack core, a reforming module, an exhaust gas treatment module, a cooling module and a heat insulation module; the heating module is used to heat the stack core and the cathode gas; the cathode gas is sent into the stack core for cathode reaction; electrochemical reaction occurs in the stack core to output electric energy outward; the electrochemical reaction includes the cathode reaction and the anode reaction; cathode exhaust gas is generated after the cathode reaction, and the cathode exhaust gas supplies heat to the reforming module; the reforming module is used to gasify and reform the reforming fuel into hydrogen-rich gas; the hydrogen-rich gas is sent into the stack core for anode reaction; the exhaust gas treatment module is used to treat the cathode exhaust gas and the anode exhaust gas and supply heat outward; the cooling module is used to cool the cold end of the stack core; the heat insulation module is used to prevent heat dissipation inside the stack; the heating module includes a heating unit, a heating block, a heat conducting block and an air preheating unit; the heating unit is used to generate heat; the heating block is arranged between the heating unit and the stack core to uniformly heat the stack core; the heat conducting block is used to conduct the heat of the heating block to the stack core; the air preheating unit is used to heat the cathode gas; the air preheating unit includes an air preheating sub-unit and an air distribution sub-unit; the air preheating sub-unit is arranged between the heating unit and the heating block and is used to heat the cathode gas by using the heat generated by the heating unit; the air distribution sub-unit is used to distribute the heated cathode gas to the stack core; the heating unit is an infrared combustion heating furnace or an electric heater; the cooling module is a cooling block and / or a cooling channel; the cooling block is arranged at the upper and lower ends of the grid plate of the stack core; the cooling channel is arranged in the middle of the grid plate of the stack core.

2. The SOFC stack according to claim 1, characterized in that, the exhaust gas treatment module includes an exhaust gas treatment unit, an anode exhaust gas dehydration unit of the stack, an inlet for the cathode exhaust gas of the stack, an inlet for the anode exhaust gas of the stack, an exhaust gas treatment outlet and a heat recovery unit; the inlet for the anode exhaust gas of the stack is used to send the anode exhaust gas into the anode exhaust gas dehydration unit of the stack; the anode exhaust gas dehydration unit of the stack is used to dehydrate the anode exhaust gas and send the dehydrated anode exhaust gas into the exhaust gas treatment unit, and a check valve is arranged between the anode exhaust gas dehydration unit of the stack and the exhaust gas treatment unit; the inlet for the cathode exhaust gas of the stack is used to send the cathode exhaust gas into the exhaust gas treatment unit; the exhaust gas treatment unit is used to supply heat by the reaction of the dehydrated anode exhaust gas and the cathode exhaust gas; the exhaust gas treatment outlet is used to discharge the exhaust gas generated after the reaction of the dehydrated anode exhaust gas and the cathode exhaust gas; the heat recovery unit is used to recover the heat generated by the reaction of the dehydrated anode exhaust gas and the cathode exhaust gas and supply heat outward.

3. The SOFC stack according to claim 1, characterized in that, it further includes a housing, the heating module, the stack core, the reforming module, the exhaust gas treatment module and the cooling module are arranged inside the housing, and heat insulation materials are arranged between each module and the inner surface of the housing.

4. The SOFC stack according to claim 1, characterized in that, the reforming module is arranged inside or outside the stack; and includes a reforming fuel gasification unit and a reformer; the reforming fuel gasification unit is used for gasifying the liquid reforming fuel; the reformer is used for reforming the gasified reforming fuel into a hydrogen-rich gas.

5. A method for starting an SOFC stack, characterized in that, the method is applied to the SOFC stack according to any one of claims 1-4, and includes, turning on the combustion blower to purge the heating module; when purging for a preset purging time, turning on the heating fuel switch valve to add heating fuel and performing automatic ignition; judging whether the ignition is successful; if the ignition is successful, adjusting the combustion parameters and judging whether the heating parameters are within a preset heating temperature range; if the heating parameters are within the preset heating temperature range, maintaining the heating parameters, monitoring the combustion state of the heating module, and judging whether to flame out; if it flames out, judging whether other components are turned on; if all other components are turned on, executing an emergency stop or one-key shutdown command; if there are unturned-on other components, closing the heating fuel switch valve and the combustion blower and giving an alarm prompt; if it does not flame out, maintaining the combustion parameters, and the maintaining the combustion parameters includes the cold end temperature, reformer temperature, stack temperature and water heater temperature; judging whether the cold end temperature is greater than or equal to the maximum cold end temperature; if so, using cooling water within a preset temperature range to cool the cold end; judging whether the reformer temperature is greater than or equal to the minimum reformer temperature; if so, turning on the reforming fuel pump to raise the reformer temperature to a preset reforming temperature range and maintaining the reformer temperature within the preset reforming temperature range; judging whether the stack temperature is greater than or equal to the minimum stack temperature; if so, turning on the cathode blower to raise the stack temperature to a preset stack temperature range and maintaining the stack temperature within the preset stack temperature range; judging whether the water heater temperature is greater than or equal to the minimum water heater temperature; if so, turning on the hot water inlet switch; if the heating parameters are not within the preset heating temperature range, adjusting the intake of the combustion blower and the heating fuel; if the ignition is not successful, repeating the ignition and judging the ignition state; if the ignition state shows successful ignition, adjusting the combustion parameters and performing subsequent steps; if the ignition state shows unsuccessful ignition, closing the heating fuel switch valve and the combustion blower and giving an alarm prompt.

6. The method for starting an SOFC stack according to claim 5, characterized in that, the executing the emergency stop or one-key shutdown command includes, gradually decreasing the reforming fuel, cathode blower and combustion blower to their respective preset values and closing the water heater inlet switch; judging whether the temperature at the cooling water outlet is less than or equal to a preset shutdown cooling temperature, judging whether the stack temperature is less than or equal to a preset stack shutdown temperature, and judging whether the reformer temperature is within a preset shutdown reforming temperature range; if all are yes, closing the heating fuel switch valve, closing the circulation pump, closing the cooling fan, closing the heating fan and closing the reforming fuel pump.

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