A fuel cell stack thermal management device for a high-power test bench

Abstract

The application relates to the technical field of fuel cell testing, in particular to a fuel cell stack heat management device for a high-power test platform, which comprises a first heat management subsystem, a second heat management subsystem, a three-way valve, a liquid supplementing and exhaust system and a fuel cell stack test system; the input ends of the first heat management subsystem and the second heat management subsystem are externally connected with a cooling water main water supply pipeline, and the output ends of the first heat management subsystem and the second heat management subsystem are externally connected with a cooling water return pipeline. The application can realize excellent heat management of the fuel cell stack under high power, and meanwhile, the accuracy and stability of temperature control during low-power operation of the fuel cell stack are considered, so that excellent temperature control effects in a wide power range are realized. Compared with the series connection mode, the parallel connection mode of the two heat management subsystems can reduce flow resistance and reduce the flow resistance of the cooling water.

Description

Technical Field

[0001] This application relates to the field of fuel cell testing technology, and in particular to a fuel cell stack thermal management device for a high-power test bench. Background Technology

[0002] In recent years, hydrogen fuel cell technology has developed rapidly, and the power of hydrogen fuel cell stacks and fuel cell engines has become increasingly larger. Fuel cell stacks and fuel cell engines with a power of over 200kW have appeared on the market. At the same time, with the advancement of fuel cell technology in vehicles, ships, aviation, distributed power generation and other fields, the power of fuel cell stacks and fuel cell engines will further increase.

[0003] With the development of high-power fuel cell stacks and fuel cell engines, new requirements have been placed on the testing equipment for these components. Currently, existing literature mentions methods for implementing testing devices for 300kW and 400kW fuel cell stacks, but testing devices for 500kW and above fuel cell stacks and engines are difficult to find. Since fuel cells operate at around 50% efficiency, they generate a large amount of heat that needs to be released promptly. This presents a challenge in achieving rapid and accurate thermal management for testing ultra-high-power fuel cell stacks and engines exceeding 500kW. Utility Model Content

[0004] The main objective of this application is to provide a thermal management device for fuel cell stacks on a high-power test bench, applicable to ultra-high-power fuel cell engines and fuel cell stack testing equipment. This invention can simultaneously address the precise temperature control required for ultra-high-power fuel cell stacks on test benches, while also considering the hydrothermal management of fuel cell stacks during low-power operation, ensuring excellent temperature control throughout the full-condition testing and verification of ultra-high-power fuel cell stacks.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] This utility model claims protection for a fuel cell stack thermal management device for a high-power test bench, including a first thermal management subsystem, a second thermal management subsystem, a three-way valve, a liquid replenishment and venting system, and a fuel cell stack testing system;

[0007] The first thermal management subsystem includes a first water supply branch, a first water return branch, a first plate heat exchanger, a first temperature sensor, a second temperature sensor, a third temperature sensor, a first pneumatic regulating valve, and a first turbine flow meter; the first temperature sensor is located on the first water supply branch, the second temperature sensor and the first pneumatic regulating valve are located on the first water return branch, the third temperature sensor is located on another outlet pipe of the first plate heat exchanger, and the first turbine flow meter is located on another inlet pipe of the first plate heat exchanger;

[0008] The second thermal management subsystem includes a second water supply branch, a second water return branch, a second plate heat exchanger, a fourth temperature sensor, a fifth temperature sensor, a sixth temperature sensor, a second pneumatic regulating valve, and a second turbine flow meter; the fourth temperature sensor is located on the second water supply branch, the fifth temperature sensor and the second pneumatic regulating valve are located on the second water return branch, the sixth temperature sensor is located on another outlet pipe of the second plate heat exchanger, and the second turbine flow meter is located on another inlet pipe of the second plate heat exchanger;

[0009] The input terminals of both the first thermal management subsystem and the second thermal management subsystem are connected to the main cooling water supply pipeline, and the output terminals of both the first thermal management subsystem and the second thermal management subsystem are connected to the cooling water return pipeline.

[0010] The three-way valve has two inlet valves and one outlet valve. The inlet valves are divided into a cold side valve and a hot side valve. The cold side valve is connected to the output of the first thermal management subsystem and / or the second thermal management subsystem. The hot side valve is connected to the output of the fuel cell stack test system. The outlet valve is connected to the input of the fuel cell stack test system.

[0011] A seventh temperature sensor is installed at the external pipeline of the cold-side valve port.

[0012] Furthermore, the input terminal of the fuel cell stack testing system includes a first conductivity sensor, an eighth temperature sensor, a first pressure sensor, and a third manual ball valve;

[0013] The output of the fuel cell stack testing system includes a fourth manual ball valve, a second pressure sensor, a ninth temperature sensor, and a third turbine flow meter.

[0014] The fuel cell stack test system is connected to the external pipeline between the output end of the fuel cell stack test system and the outlet valve of the three-way valve.

[0015] Furthermore, the liquid replenishment and venting system includes a fifth manual ball valve, a second filter, a first solenoid valve, a second solenoid valve, a floor drain, a first vent, a first throttle valve, a first vent pipe, a transparent hose, and a water tank. The water tank inlet is connected to the fifth manual ball valve, the second filter, and the first solenoid valve. The top of the water tank has a first vent extending outward through a pipe, and a dustproof connector is installed on the first vent. The transparent hose, the first throttle valve, and the first vent pipe are connected sequentially on the upper side of the water tank away from the vent. The lower side of the water tank is connected to the floor drain through the second solenoid valve. The fifth manual ball valve is used to manually control the opening and closing of the water replenishment when water needs to be replenished. The second filter is used to filter impurities and particles. The first solenoid valve is used to automatically open according to the liquid level to perform the water replenishment operation. There are three liquid level switches on the water tank for convenient real-time monitoring of the water tank liquid level. The second solenoid valve is used to drain excess water to the floor drain.

[0016] Furthermore, the second thermal management subsystem is activated only when the heat dissipation capacity of the first thermal management subsystem is about to reach its limit; or, the first and second thermal management subsystems are activated simultaneously.

[0017] Furthermore, more thermal management subsystems can be connected in parallel to meet the heat dissipation requirements during testing of higher-power fuel cell stacks.

[0018] Furthermore, when it is necessary to solve for the opening degree of the three-way valve, an adaptive algorithm is used.

[0019] Furthermore, a first filter is installed at the front end of the main cooling water supply pipeline.

[0020] Furthermore, the first liquid level switch is used for high liquid level monitoring, the second liquid level switch is used for low liquid level monitoring, and the third liquid level switch is used for alarm prompts when the liquid level is abnormal.

[0021] This application relates to the field of fuel cell testing technology, and more particularly to a fuel cell stack thermal management device for a high-power test bench. It employs two parallel thermal management subsystems connected in conjunction with a three-way valve. Based on the different operating power of the fuel cell stack, an adaptive algorithm automatically controls and adjusts the opening of each valve. The three-way valve adjusts the opening to appropriately distribute the flow rates of cold and hot water. The temperature of the cold water is achieved through heat exchange with external cooling water via a plate heat exchanger. Precise temperature regulation is achieved by controlling the opening of a pneumatic regulating valve to adjust the flow rate of the external cooling water. This application achieves excellent thermal management of the fuel cell stack at high power while simultaneously ensuring accurate and stable temperature control during low-power operation, resulting in excellent temperature control performance over a wide power range. Compared to a series connection, the parallel connection of the two thermal management subsystems reduces flow resistance and the resistance to cooling water flow. Furthermore, the liquid replenishment and venting system can expel air from the cooling water and replenish high-quality cooling water, further improving the temperature control performance of the fuel cell stack. Attached Figure Description

[0022] Figure 1 This is a structural diagram of a high-power test bench fuel cell stack thermal management device claimed in the embodiments of this application;

[0023] Figure 2 This is a second structural diagram of a high-power test bench fuel cell stack thermal management device claimed in an embodiment of this application;

[0024] Figure 3 A schematic diagram of a liquid replenishment and venting device for a high-power test bench fuel cell stack thermal management apparatus as claimed in this application;

[0025] Figure 4 A structural diagram of the water supply and return circuit of a high-power test bench fuel cell stack thermal management device claimed in this application;

[0026] Figure 5 A flowchart illustrating the operation of a high-power test bench thermal management device for a fuel cell stack, as claimed in an embodiment of this application.

[0027] Figure 6 A schematic diagram of the equal percentage flow rate curve of a high-power test bench fuel cell stack thermal management device claimed in the embodiments of this application;

[0028] Figure 7 A transient loading schematic diagram of a high-power test bench fuel cell stack thermal management device claimed in an embodiment of this application;

[0029] Figure 8 This is a transient load reduction diagram of a high-power test bench fuel cell stack thermal management device claimed in an embodiment of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0031] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] According to a first embodiment of the present invention, the present invention claims protection for a fuel cell stack thermal management device for a high-power test bench, comprising a first thermal management subsystem, a second thermal management subsystem, a three-way valve, a liquid replenishment and venting system, and a fuel cell stack testing system;

[0034] The first thermal management subsystem includes a first water supply branch, a first water return branch, a first plate heat exchanger, a first temperature sensor, a second temperature sensor, a third temperature sensor, a first pneumatic regulating valve, and a first turbine flow meter; the first temperature sensor is located on the first water supply branch, the second temperature sensor and the first pneumatic regulating valve are located on the first water return branch, the third temperature sensor is located on another outlet pipe of the first plate heat exchanger, and the first turbine flow meter is located on another inlet pipe of the first plate heat exchanger;

[0035] The second thermal management subsystem includes a second water supply branch, a second water return branch, a second plate heat exchanger, a fourth temperature sensor, a fifth temperature sensor, a sixth temperature sensor, a second pneumatic regulating valve, and a second turbine flow meter; the fourth temperature sensor is located on the second water supply branch, the fifth temperature sensor and the second pneumatic regulating valve are located on the second water return branch, the sixth temperature sensor is located on another outlet pipe of the second plate heat exchanger, and the second turbine flow meter is located on another inlet pipe of the second plate heat exchanger;

[0036] The input terminals of both the first thermal management subsystem and the second thermal management subsystem are connected to the main cooling water supply pipeline, and the output terminals of both the first thermal management subsystem and the second thermal management subsystem are connected to the cooling water return pipeline.

[0037] The three-way valve has two inlet valves and one outlet valve. The inlet valves are divided into a cold side valve and a hot side valve. The cold side valve is connected to the output of the first thermal management subsystem and / or the second thermal management subsystem. The hot side valve is connected to the output of the fuel cell stack test system. The outlet valve is connected to the input of the fuel cell stack test system.

[0038] A seventh temperature sensor is installed at the external pipeline of the cold-side valve port.

[0039] Furthermore, the input terminal of the fuel cell stack testing system includes a first conductivity sensor, an eighth temperature sensor, a first pressure sensor, and a third manual ball valve;

[0040] The output of the fuel cell stack testing system includes a fourth manual ball valve, a second pressure sensor, a ninth temperature sensor, and a third turbine flow meter.

[0041] The fuel cell stack test system is connected to the external pipeline between the output end of the fuel cell stack test system and the outlet valve of the three-way valve.

[0042] Furthermore, the liquid replenishment and venting system includes a fifth manual ball valve, a second filter, a first solenoid valve, a second solenoid valve, a floor drain, a first vent, a first throttle valve, a first vent pipe, a transparent hose, and a water tank. The water tank inlet is connected to the fifth manual ball valve, the second filter, and the first solenoid valve. The top of the water tank has a first vent extending outward through a pipe, and a dustproof connector is installed on the first vent. The transparent hose, the first throttle valve, and the first vent pipe are connected sequentially on the upper side of the water tank away from the vent. The lower side of the water tank is connected to the floor drain through the second solenoid valve. The fifth manual ball valve is used to manually control the opening and closing of the water replenishment when water needs to be replenished. The second filter is used to filter impurities and particles. The first solenoid valve is used to automatically open according to the liquid level to perform the water replenishment operation. There are three liquid level switches on the water tank for convenient real-time monitoring of the water tank liquid level. The second solenoid valve is used to drain excess water to the floor drain.

[0043] Furthermore, the second thermal management subsystem is activated only when the heat dissipation capacity of the first thermal management subsystem is about to reach its limit; or, the first and second thermal management subsystems are activated simultaneously.

[0044] Furthermore, more thermal management subsystems can be connected in parallel to meet the heat dissipation requirements during testing of higher-power fuel cell stacks.

[0045] Furthermore, when it is necessary to solve for the opening degree of the three-way valve, an adaptive algorithm is used.

[0046] Furthermore, a first filter is installed at the front end of the main cooling water supply pipeline.

[0047] Furthermore, the first liquid level switch is used for high liquid level monitoring, the second liquid level switch is used for low liquid level monitoring, and the third liquid level switch is used for alarm prompts when the liquid level is abnormal.

[0048] In this embodiment, reference is made to Figure 1 and 2 This embodiment shows a structural diagram of a fuel cell generator and a fuel cell stack thermal management device for a high-power test bench.

[0049] T1: The value monitored by the first temperature sensor;

[0050] T2: The value monitored by the second temperature sensor;

[0051] T3: The monitoring value of the third temperature sensor;

[0052] T4: The monitoring value of the fourth temperature sensor;

[0053] T5: The monitoring value of the fifth temperature sensor;

[0054] T6: The monitoring value of the sixth temperature sensor;

[0055] T7: The monitored value of the seventh temperature sensor;

[0056] T8: The monitored value of the eighth temperature sensor;

[0057] T9: The monitoring value of the ninth temperature sensor;

[0058] Cc: Monitoring value from the conductivity sensor

[0059] P1: The monitored value of the first pressure sensor;

[0060] P2: The monitoring value of the second pressure sensor;

[0061] F1: The monitored value of the first turbine flow meter;

[0062] F2: The monitored value of the second turbine flow meter;

[0063] F3: Monitoring value of the third turbine flow meter;

[0064] c: Specific heat capacity of cooling water;

[0065] Tset: The inlet set temperature of the fuel cell engine (fuel cell stack), i.e., the target temperature of the cooling water;

[0066] m_cold: The flow rate (in L / min) of the cooling water at the fuel cell stack outlet that exchanges heat with the outside through the thermal management subsystem (first thermal management subsystem and / or second thermal management subsystem);

[0067] m_heat: The mass of water flow rate in the cooling water at the fuel cell stack outlet that has not passed through the thermal management subsystem, i.e., the portion that circulates directly from the fuel cell stack outlet to the fuel cell stack inlet through the three-way valve (unit: L / min);

[0068] m_total: Total flow rate in the fuel cell stack cooling loop (unit: L / min, i.e., the value monitored by turbine flow meter F3);

[0069] m External cooling water: The flow rate of external cooling water through the plate heat exchanger (Note: Generally, the mass per unit time (min) is taken);

[0070] φcold: Cold side opening of the three-way valve;

[0071] φhot: The opening degree of the hot side of the three-way valve, where φcold + φhot = 100%;

[0072] φ1: Opening degree of the first pneumatic regulating valve;

[0073] φ2: Opening degree of the second pneumatic control valve;

[0074] During operation, Cc is monitored in real time by a conductivity sensor to prevent electrical safety issues from arising due to increased conductivity of cooling water and decreased insulation.

[0075] Furthermore, the first thermal management subsystem is equipped with a first turbine flow meter, the second thermal management subsystem is equipped with a second turbine flow meter, and a third turbine flow meter is installed on the main cooling water circuit. For ease of monitoring, the flow allocated to the first and second thermal management subsystems is designed with equal flow resistance to achieve a 50%:50 flow distribution. However, in practical applications, various factors may lead to uneven flow distribution between the two subsystems, affecting the opening adjustment of the first and second pneumatic regulating valves. Therefore, real-time monitoring of the flow allows for further calculation of the heat dissipation borne by each subsystem, enabling independent control of the two thermal management subsystems.

[0076] Furthermore, each thermal management subsystem's plate heat exchanger outlet is equipped with a temperature sensor.

[0077] Furthermore, the two thermal management subsystems can also be controlled using a "synchronous" method for temperature regulation. That is, regardless of the low, medium, or high power range, the first and second thermal management subsystems each undertake 50% of the heat dissipation demand, i.e., the opening degrees of the first and second pneumatic regulating valves are adjusted synchronously.

[0078] The above describes the parallel connection of two thermal management subsystems, which can meet the heat dissipation requirements of an 800kW fuel cell engine (1000kW, or 1MW fuel cell stack) at its maximum. Further thermal management subsystems can be connected in parallel to meet the heat dissipation requirements of higher power fuel cell engines (fuel cell stacks) during testing.

[0079] A single thermal management subsystem can be used as the thermal management system for 200kW or 300kW test equipment, and it has strong backward and upward compatibility.

[0080] The thermal management system for testing low- and medium-power fuel cell engines (fuel cell stacks) can also adopt the above-mentioned parallel connection of multiple thermal management subsystems to achieve higher precision temperature control.

[0081] Figure 3 This is the replenishment and venting system for the thermal management system. Deionized water (or fuel cell stack-specific coolant) is injected into the thermal management system as needed. The fifth manual ball valve allows for manual control of the water replenishment process. The second filter filters the water to prevent impurities from entering the system. The first solenoid valve automatically opens based on the water level for replenishment. The water tank has three level switches for real-time monitoring. The first level switch monitors high levels; when the level is higher, the second solenoid valve automatically opens to drain excess water to a floor drain (or a designated location). The second level switch monitors low levels; when the level is lower, the first solenoid valve automatically opens to replenish water. The third level switch provides an alarm; when the level is detected at a certain point, the operator is alerted to check the water tank for any abnormalities.

[0082] The water tank fills the pipelines in the thermal management system with water supply pipe, and the thermal management system vents the pipelines with exhaust pipe. The water flow rate during venting can be adjusted by adjusting the throttle valve, and the transparent rubber tube makes it easy to observe the venting effect.

[0083] A vent is provided on the water tank via a pipe extending outwards, and a dustproof connector is installed on the vent to prevent external dust and other impurities from entering the water tank.

[0084] Reference Figure 4The first manual ball valve in the supply and return water circuit manually controls the opening and closing of the cooling water supply. The first filter filters out rust and other impurities from the external cooling water, preventing these particles from entering the thermal management system and causing blockages in the plate heat exchanger. The first filter is connected to the main supply water pipeline, which extends into two branches: the first supply water branch and the second supply water branch. Generally, the diameter of the main supply water pipeline is larger than that of the supply water branches. The first and second return water branches converge into the main return water pipeline. Generally, the diameter of the main return water pipeline is larger than that of the return water branches. The second manual ball valve manually controls the opening and closing of the cooling water return.

[0085] Furthermore, the method of using the aforementioned high-power test bench fuel cell stack thermal management device is as follows: (Refer to...) Figure 5 :

[0086] The fuel cell stack or fuel cell engine is cold-started at room temperature idling speed to obtain the optimal operating temperature of the fuel cell stack. Based on the temperature value of the ninth temperature sensor, the cold side valve port of the three-way valve is fully closed and the hot side valve port is fully open to control the outlet temperature of the fuel cell stack to reach the optimal operating temperature.

[0087] Real-time monitoring of the coolant temperature, outlet pressure, and coolant flow rate of the fuel cell stack;

[0088] When the coolant temperature of the fuel cell stack exceeds the optimal operating temperature of the fuel cell stack, the opening of the three-way valve, the opening of the first pneumatic regulating valve and / or the second pneumatic regulating valve are adjusted according to the operating power range of the fuel cell stack, so that part or all of the external cooling water can exchange heat with the coolant through the first thermal management subsystem and / or the second thermal management subsystem.

[0089] Furthermore, the process of cold-starting the fuel cell stack or fuel cell engine at ambient temperature idle speed to obtain the optimal operating temperature of the fuel cell stack, and controlling the outlet temperature of the fuel cell stack to reach the optimal operating temperature by fully closing the cold side valve port and fully opening the hot side valve port of the three-way valve based on the temperature value of the ninth temperature sensor, further includes:

[0090] When the fuel cell stack or fuel cell engine is cold-started at room temperature idling speed, the coolant temperature is the temperature value of the ninth temperature sensor under normal temperature conditions, and the optimal operating temperature of the proton exchange membrane fuel cell stack is greater than the coolant temperature.

[0091] The heat released during the operation of the fuel cell stack raises the temperature of the coolant from the coolant temperature to the set optimal operating temperature.

[0092] At this time, the cold side valve port of the three-way valve is fully closed, and the hot side valve port is fully open.

[0093] In this embodiment, during a cold start at room temperature idling speed, the coolant temperature T9 (the temperature T9 monitored by the fuel cell stack outlet temperature sensor 9) is 25°C. The optimal operating temperature for a proton exchange membrane fuel cell stack is typically 60–80°C (target set temperature Tset). Therefore, under these conditions, when T9 < Tset, not only is heat exchange between the thermal management system and the external environment unnecessary, but the heat released during fuel cell stack operation is used to rapidly raise the coolant temperature from 25°C to the set temperature Tset (60–80°C). At this time, the three-way valve is fully closed on the cold side and fully open on the hot side, i.e., φcold = 0% and φhot = 100%.

[0094] Furthermore, real-time monitoring of the coolant temperature, outlet water pressure, and coolant flow rate of the fuel cell stack also includes:

[0095] The temperature value of the eighth temperature sensor of the fuel cell stack, the inlet water pressure value of the first pressure sensor, the temperature value of the ninth temperature sensor of the fuel cell stack, the outlet water pressure value of the second pressure sensor, the coolant conductivity of the first conductivity sensor, and the coolant flow rate value of the third turbine flow meter are monitored in real time.

[0096] Furthermore, when the coolant temperature of the fuel cell stack exceeds the optimal operating temperature of the fuel cell stack, the opening of the three-way valve, the opening of the first pneumatic regulating valve, and / or the second pneumatic regulating valve are adjusted according to the operating power range of the fuel cell stack, so that part or all of the external cooling water exchanges heat with the coolant through the first thermal management subsystem and / or the second thermal management subsystem, further comprising:

[0097] When the operating power range of the fuel cell stack is low power or medium power, one of the first thermal management subsystem or the second thermal management subsystem is activated and its opening is adjusted in accordance with the three-way valve.

[0098] An adaptive algorithm is used to solve the opening degree of the first pneumatic regulating valve or the second pneumatic regulating valve and the three-way valve in real time, so that the input temperature value of the fuel cell stack does not differ from the optimal operating temperature by more than a first threshold.

[0099] In this embodiment, T9 > Tset. When the fuel cell engine (fuel cell stack) operates in the low and medium power range, the heat generated by the fuel cell stack is relatively small. To maintain the operating temperature of the fuel cell stack, the heat exchange between the thermal management system and the outside is small. At this time, only one thermal management subsystem needs to participate in thermal management to achieve the temperature control effect. That is, the first thermal management subsystem (or the second thermal management subsystem) operates independently, while the opening of the three-way valve is matched and adjusted. The opening of the first pneumatic regulating valve (or the second pneumatic regulating valve) and the three-way valve are solved in real time through an adaptive algorithm to ensure that T8 = Tset ± δ, δ ≤ 3℃. When the opening of the three-way valve remains constant, the opening of the cold side valve of the three-way valve remains at the value before the transient load, and the relative percentage of cold water and hot water flow through the three-way valve remains unchanged, that is, the amount of external cooling water of the fuel cell stack participating in external heat exchange remains unchanged.

[0100] Lowering the temperature of the cold side valve port of the three-way valve releases excess heat. By automatically and timely increasing the opening of the first pneumatic regulating valve or the second regulating valve, the optimal solution for the opening of the first pneumatic regulating valve or the second regulating valve is sought in real time, thereby increasing the heat exchange between the coolant and the external cooling water, reducing the coolant temperature, and achieving temperature control during transient loading.

[0101] In this embodiment, the opening of the three-way valve remains constant, i.e., φcold remains at the value before transient loading (φcold ≠ 0). The relative percentage of cold water and hot water flow through the three-way valve remains unchanged, meaning the amount of cooling water in the fuel cell stack participating in external heat exchange remains constant. Excess heat is released by lowering the cold water temperature T7. In other words, by automatically and timely increasing the opening of the first or second pneumatic regulating valve, the optimal solution for the opening of the first or second pneumatic regulating valve is sought in real time, increasing the heat exchange between the cooling water and the external cold water, thereby lowering the cold water temperature T9 and achieving temperature control during transient loading.

[0102] Furthermore, the method also includes:

[0103] When the opening of the three-way valve remains constant and it is difficult to achieve the target, the opening of the cold side valve of the three-way valve is automatically adjusted to redistribute the relative percentages of cold and hot water flow.

[0104] The target temperature regulation value of the first thermal management subsystem or the second thermal management subsystem is calculated based on the cold side valve port of the new three-way valve.

[0105] By adjusting the opening of the first pneumatic regulating valve or the second regulating valve, the difference between the temperature at the cold side valve port of the three-way valve and the target temperature value is made not greater than the second threshold.

[0106] Furthermore, the opening of the three-way valve is automatically adjusted in a timely manner to redistribute the relative percentages of cold and hot water flow. Based on the new φcold, Tcold is calculated and used as the temperature regulation target value for the first thermal management subsystem (or the second thermal management subsystem), with T7 being the measured feedback value. T7 = Tcold ± δ1, where δ1 ≤ 1℃, is achieved by adjusting the opening of the first pneumatic regulating valve (or the second pneumatic regulating valve).

[0107] The specific process is as follows:

[0108] φcold = mcold / mtotal;

[0109] Based on cm_cold(T_hot - T_cold) = cm_total(T_hot - T_set), we obtain...

[0110] This yields the relationship between the cold water opening degree φcold and Tcold of the three-way valve. During temperature control adjustment, Tcold is automatically calculated based on the current value of φcold. Tcold is the temperature control target of the heat management subsystem, and T7 is the feedback value during the adjustment process.

[0111] According to cm_cold(T_hot - T_cold) = cm_external_cooling_water(T2 - T1), the relationship curve (equal percentage flow rate curve) between the opening degree φ1 of the first pneumatic regulating valve (the opening degree φ2 of the second pneumatic regulating valve) and m_external_cooling_water is shown below. Figure 6 As shown;

[0112] This establishes the relationship between φ1 (φ2) and the external cooling water (m), meaning that temperature control can be performed without monitoring the external cooling water (m). Furthermore, T2 and T1 can be ignored, and the target value of T_cooling can be achieved entirely through PID control. Furthermore, installing a turbine flow meter to monitor the external cooling water (m) in real time can further improve temperature control accuracy.

[0113] The opening degree φ1 of the first pneumatic regulating valve (or the opening degree φ2 of the second pneumatic regulating valve) is automatically adjusted by PID control to ensure that T7 = T_cold. Finally, the cold and hot water are mixed through a three-way valve, and the temperature of the mixed cooling water is T_set, thus achieving precise control of the target temperature.

[0114] In summary, the entire temperature control process is essentially a process of finding the optimal solution for φ_cold and φ_1 (or φ_2) in real time and dynamically.

[0115] When the fuel cell engine (fuel cell stack) is running in steady state (i.e., running at a fixed power point), the heat generated by the fuel cell stack is almost stable at a certain value with little fluctuation. In this state, after finding the optimal solution for φ_cold and φ_1, it is only necessary to maintain the optimal opening value and make fine adjustments to the P_ID to achieve the desired effect by adjusting the temperature fluctuations.

[0116] Reference Figure 7 and 8When the fuel cell engine (fuel cell stack) is in transient operation (i.e., from a low power point to a high power point, or from a high power point to a low power point), the operating power of the fuel cell stack changes abruptly. At this time, φ_cool and φ_1 are also adjusted quickly to achieve a rapid surge or sharp decrease in heat dissipation. After the fuel cell stack stabilizes, φ_cool and φ_1 are also finely adjusted up and down from the stable value (optimal solution).

[0117] Furthermore, the method also includes:

[0118] When the operating power range of the fuel cell stack is the high power range and the corresponding pneumatic regulating valve in the first thermal management subsystem or the second thermal management subsystem reaches the upper limit of heat dissipation capacity, the other thermal management subsystem in the first thermal management subsystem or the second thermal management subsystem is opened.

[0119] The power of the fuel cell stack continues to increase, following the coordinated adjustment of the first pneumatic regulating valve, the second pneumatic regulating valve, and the three-way valve;

[0120] The first pneumatic regulating valve and the second pneumatic regulating valve work together to achieve the target cooling temperature value of the three-way valve in its open state.

[0121] In this embodiment, when the fuel cell engine (fuel cell stack) operates at high power, the fuel cell stack generates a significant amount of heat. To maintain the operating temperature of the fuel cell stack, two thermal management subsystems need to coordinate to achieve high-power heat dissipation. Specifically, when both φcold and φ1 are at a high opening degree (e.g., 80%), indicating that the heat dissipation capacity of the first thermal management subsystem is approaching its limit, the second thermal management subsystem gradually engages. That is, the opening degree φ2 of the second pneumatic regulating valve gradually starts from 0 and adjusts accordingly as the power of the fuel cell stack further increases. In other words, the first pneumatic regulating valve, the second pneumatic regulating valve, and the three-way valve work synergistically. The first and second pneumatic regulating valves work together to achieve the target value Tcold under the three-way valve φcold opening degree.

[0122] Furthermore, the opening degrees of the first pneumatic regulating valve, the second pneumatic regulating valve, and the three-way valve are solved in real time using an adaptive algorithm, so that the input temperature value of the fuel cell stack does not differ from the optimal operating temperature by more than a first threshold.

[0123] The aforementioned are the first and second thermal management subsystems, employing a "one primary, one secondary" thermal management method. This means the first thermal management subsystem is the primary system, and the second is secondary. The second thermal management subsystem is activated only when the first subsystem's heat dissipation capacity reaches or is about to reach its maximum. Alternatively, the second thermal management subsystem can be the primary system, with the first secondary. Furthermore, the first and second thermal management subsystems can be controlled synchronously for temperature regulation. That is, regardless of whether the fuel cell stack or fuel cell engine is operating at low, medium, or high power, the first and second thermal management subsystems each handle 50%:50% of the heat dissipation demand, achieved through synchronous regulation using the first and second pneumatic regulating valves.

[0124] The aforementioned high-power test bench fuel cell stack thermal management method and apparatus can, at its maximum, meet the heat dissipation requirements of an 800kW fuel cell engine (1MW fuel cell stack). Furthermore, this thermal management apparatus can be connected in parallel with more thermal management subsystems to meet the heat dissipation requirements during testing of even higher-power fuel cell engines (fuel cell stacks).

[0125] The aforementioned thermal management device for fuel cell stacks in high-power test benches is also applicable to the thermal management of fuel cell stacks in medium and low-power test benches, enabling higher precision temperature control. In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings or direct couplings or communication connections may be through some interfaces, or indirect couplings or communication connections between devices or units, and may be electrical, mechanical, or other forms.

[0126] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units. The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0127] The specific embodiments of the invention have been described in detail above, but they are only examples, and this application is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions to the invention are also within the scope of this application. Therefore, all equivalent changes, modifications, and improvements made without departing from the spirit and principles of this application should be covered within the scope of this application.

Claims

1. A thermal management device for a fuel cell stack used in a high-power test bench, characterized in that, It includes a first thermal management subsystem, a second thermal management subsystem, a three-way valve, a liquid replenishment and venting system, and a fuel cell stack testing system; The first thermal management subsystem includes a first water supply branch, a first water return branch, a first plate heat exchanger, a first temperature sensor, a second temperature sensor, a third temperature sensor, a first pneumatic regulating valve, and a first turbine flow meter; the first temperature sensor is located on the first water supply branch, the second temperature sensor and the first pneumatic regulating valve are located on the first water return branch, the third temperature sensor is located on another outlet pipe of the first plate heat exchanger, and the first turbine flow meter is located on another inlet pipe of the first plate heat exchanger; The second thermal management subsystem includes a second water supply branch, a second water return branch, a second plate heat exchanger, a fourth temperature sensor, a fifth temperature sensor, a sixth temperature sensor, a second pneumatic regulating valve, and a second turbine flow meter; the fourth temperature sensor is located on the second water supply branch, the fifth temperature sensor and the second pneumatic regulating valve are located on the second water return branch, the sixth temperature sensor is located on another outlet pipe of the second plate heat exchanger, and the second turbine flow meter is located on another inlet pipe of the second plate heat exchanger; The input terminals of both the first thermal management subsystem and the second thermal management subsystem are connected to the main cooling water supply pipeline, and the output terminals of both the first thermal management subsystem and the second thermal management subsystem are connected to the cooling water return pipeline. The three-way valve has two inlet valves and one outlet valve. The inlet valves are divided into a cold side valve and a hot side valve. The cold side valve is connected to the output of the first thermal management subsystem and / or the second thermal management subsystem. The hot side valve is connected to the output of the fuel cell stack test system. The outlet valve is connected to the input of the fuel cell stack test system. A seventh temperature sensor is installed at the external pipeline of the cold-side valve port.

2. The fuel cell stack thermal management device for a high-power test bench as described in claim 1, characterized in that, The input terminals of the fuel cell stack testing system include a first conductivity sensor, an eighth temperature sensor, a first pressure sensor, and a third manual ball valve. The output of the fuel cell stack testing system includes a fourth manual ball valve, a second pressure sensor, a ninth temperature sensor, and a third turbine flow meter. The fuel cell stack test system is connected to the external pipeline between the output end of the fuel cell stack test system and the outlet valve of the three-way valve.

3. The fuel cell stack thermal management device for a high-power test bench as described in claim 2, characterized in that, The liquid replenishment and venting system includes a fifth manual ball valve, a second filter, a first solenoid valve, a second solenoid valve, a floor drain, a first vent, a first throttle valve, a first vent pipe, a transparent hose, and a water tank. The water tank inlet is connected to the fifth manual ball valve, the second filter, and the first solenoid valve. The top of the water tank has a first vent extending outward through a pipe, and a dustproof connector is installed on the first vent. The transparent hose, the first throttle valve, and the first vent pipe are connected sequentially on the upper side of the water tank away from the vent. The lower side of the water tank is connected to the floor drain through the second solenoid valve. The fifth manual ball valve is used to manually control the opening and closing of the water replenishment when water needs to be replenished. The second filter is used to filter impurities and particles. The first solenoid valve is used to automatically open according to the liquid level to perform the water replenishment operation. There are 3 liquid level switches on the water tank for convenient real-time monitoring of the water tank liquid level. The second solenoid valve is used to drain excess water to the floor drain.

4. The fuel cell stack thermal management device for a high-power test bench as described in claim 3, characterized in that, The second thermal management subsystem is activated only when the heat dissipation capacity of the first thermal management subsystem is about to reach its limit.

5. The fuel cell stack thermal management device for a high-power test bench as described in claim 3, characterized in that, The first and second thermal management subsystems are activated simultaneously.

6. The fuel cell stack thermal management device for a high-power test bench as described in claim 3, characterized in that, Connect more thermal management subsystems in parallel to meet the heat dissipation requirements during testing of higher-power fuel cell stacks.

7. A fuel cell stack thermal management device for a high-power test bench as described in any one of claims 4-6, characterized in that, When it is necessary to solve for the opening degree of a three-way valve, an adaptive algorithm is used.

8. The fuel cell stack thermal management device for a high-power test bench as described in claim 7, characterized in that, A first filter is installed at the front end of the main cooling water supply pipeline.

9. A fuel cell stack thermal management device for a high-power test bench as described in claim 8, characterized in that, The first liquid level switch is used for high liquid level monitoring, the second liquid level switch is used for low liquid level monitoring, and the third liquid level switch is used for alarm prompts when the liquid level is abnormal.

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