A cooling circuit safe venting BOP test bench

Abstract

This invention relates to the field of hydrogen fuel cells, and more particularly to a BOP (Body-on-Pack) test bench with a safe venting cooling circuit. It includes an air circuit test system, a hydrogen circuit test system, a shared cooling system for both, and an FCU (Fuel Unit) for controlling various electrical components. An auxiliary cooling circuit is connected to the cooling system; the auxiliary cooling circuit includes an expansion tank with a pressure cap, through which water is added, drained, and vented. This invention combines commercially available air and hydrogen circuit test benches, allowing both circuits to share a single cooling system and incorporating an auxiliary cooling circuit. This significantly reduces testing costs, improves space utilization, and reduces operational steps, saving considerable time and labor costs. The cooling system can adjust the temperature of different circuits and can also heat the gas in the hydrogen circuit, completely simulating the temperature at which hydrogen enters the fuel cell stack, greatly increasing the realism of the simulation test.

Description

Technical Field

[0001] This utility model relates to the field of hydrogen fuel cells, and in particular to a BOP test bench with a cooling circuit that can be safely vented. Background Technology

[0002] In the hydrogen industry, BOP refers to the fuel cell auxiliary system, an abbreviation for Balance of Plant. It refers to the non-battery components of a hydrogen fuel cell system, including the air supply system, hydrogen circulation system, cooling system, control and monitoring system, etc. Core components include air compressors, circulation pumps, humidifiers, water pumps, and hydrogen pumps. These are the foundation of the overall function of the hydrogen fuel cell system and are key components ensuring its normal operation. The cooling system, in particular, is crucial for the safe operation of the entire system, ensuring that the temperature is controlled within a reasonable range.

[0003] Commercially available BOP test benches typically use simple cooling circuits to cool test components in air or hydrogen circuits, but they don't address the issue of venting within these circuits. If venting is not successful, the cooling of the BOP component will be affected. Furthermore, commercially available BOP test benches can only cool a single path, resulting in a wide temperature range. They cannot simultaneously control the temperature in different circuits, making simple cooling circuits ineffective for circuits with specific temperature requirements. Multiple cooling circuits increase costs, and uncontrollable temperatures can introduce significant errors into the test. Utility Model Content

[0004] To address the problems existing in the background technology, a BOP test bench with a safe venting cooling circuit is proposed, including an air circuit test system, a hydrogen circuit test system, a cooling system shared by both, and an FCU that controls each electrical component; an auxiliary cooling circuit is connected to the cooling system; the auxiliary cooling circuit includes an expansion tank with a pressure cover, and the expansion tank is used to complete water filling, drainage and venting.

[0005] Preferably, the air circuit test system includes an air filter, an air flow meter, an air compressor test piece, a temperature / pressure sensor, an intercooler test piece, a throttle valve, and a first switching valve connected in sequence; the air compressor test piece and the intercooler test piece are connected on one hand through a manual switching valve, and on the other hand through a second switching valve and a first thermostat; the outlet end of the intercooler test piece is connected to a third switching valve.

[0006] Preferably, the hydrogen circuit testing system includes a switching valve six and a gas preheater connected in sequence; the outlet one of the gas preheater is connected in sequence to a proportional valve, a gas cooler, a hydrogen flow meter one, and a hydrogen pump test piece; the outlet two is connected in sequence to an ejector test piece, a hydrogen flow meter two, and a switching valve seven; the outlet one of the hydrogen pump test piece is connected to the pipeline between the proportional valve and the gas cooler; the outlet two is connected to the tailpipe pipeline of the switching valve seven through a switching valve nine; the outlet three is connected to a thermostat two through a switching valve four; a switching valve eight and a hydrogen flow meter three are also connected between the ejector test piece and the hydrogen flow meter two; the gas preheater, PTC, water pump two, and temperature sensor are connected in sequence to form a gas temperature regulation cycle.

[0007] Preferably, the cooling system includes a radiator; the outlet of the radiator is sequentially connected to a water pump, a cooling flow meter, a thermostat, a switching valve, and a hydrogen pump test piece, and the inlet is connected to the intercooler test piece via a switching valve; the outlet of the gas cooler is connected to the pipeline between the radiator and the switching valve, and the inlet is connected to the pipeline between the radiator and the switching valve via a thermostat; a manual switching valve is connected to the pipeline between the air compressor test piece and the intercooler test piece, on the side closer to the intercooler test piece.

[0008] Preferably, the auxiliary cooling circuit includes an outlet valve A connecting the expansion tank to the radiator and water pump one, an outlet valve B connecting the expansion tank to the PTC and water pump two, an inlet valve C connecting the expansion tank to the water pump two and the temperature sensor, an inlet valve D connecting the inlet valve and the pipeline between the switch valve four and the hydrogen pump under test, and an inlet valve E connecting the expansion tank and the radiator.

[0009] Preferably, the outlet valve a of the thermostat is connected to the switching valve two, the outlet valve b is connected to the intercooler test piece, and the inlet is connected to the pipeline between the cooling flow meter and the switching valve five.

[0010] Preferably, the outlet valve a of the thermostat two is connected to the gas cooler, the outlet valve b is connected to the pipeline between the radiator and the switch three, and the inlet valve is connected to the gas cooler.

[0011] Preferably, the pressure cover of the expansion tank is connected to the tank body by a spring.

[0012] Compared with existing technologies, this utility model has the following beneficial technical effects: The BOP test bench proposed in this utility model, through a highly integrated common cooling system and innovative auxiliary cooling circuit design, achieves efficient compatibility and precise control of the testing requirements for air and hydrogen circuits, which has significant advantages over traditional solutions. Its core lies in integrating the cooling requirements of key BOP components such as air compressors, intercoolers, hydrogen pumps, and gas coolers into a single cooling circuit, and utilizing a precise valve network (thermostats one / two, on / off valve groups, and manual valves) to achieve intelligent distribution and isolation of coolant, significantly saving equipment costs and space while improving the flexibility of test switching. The system, through independently adjustable thermostats a / b and associated valves, provides refined temperature control capabilities for individual or combined test components, accurately adjusting coolant flow rate and velocity to meet the requirements of harsh operating condition simulation and fault mode testing, significantly improving testing accuracy and research depth. To address the challenges of realistic hydrogen circuit testing, the patented system integrates a closed-loop gas temperature regulation cycle consisting of a PTC heater, a second water pump, and a temperature sensor. This dynamically simulates the hydrogen inlet temperature of a fuel cell and allows for real-time adjustment of heating power and water flow rate via the FCU, providing a realistic and controllable environment for hydrogen pump and ejector performance testing. Crucially, the expansion tank with a spring-loaded pressure cap and auxiliary cooling circuit create an automated safety venting mechanism. Before startup and during operation, residual gas in the pipelines and BOP components is continuously collected and automatically discharged, effectively preventing cooling efficiency reduction, localized overheating, and test interruption risks caused by gas resistance. It also allows for convenient water addition and drainage, ensuring the long-term reliability of the system and the stability of experimental data. At the control level, a commercially available general-purpose FCU is used as the integrated control core, uniformly coordinating complex logic such as cooling distribution, temperature simulation, and flow and pressure regulation. Compared to traditional PLC solutions, this reduces development barriers and maintenance costs and supports rapid adaptation to different test scenarios through program rewriting. In summary, this design achieves breakthroughs in multiple dimensions in terms of system integration, test functionality, environmental simulation realism, operational security, and ease of operation, providing an efficient, reliable, and economical comprehensive test platform for the research and verification of BOP components. Attached Figure Description

[0013] Figure 1 A schematic diagram of the working principle of a BOP test bench that allows for safe venting of the cooling circuit. Detailed Implementation

[0014] This utility model proposes a BOP test bench with a cooling circuit that can safely vent air, including an air circuit test system, a hydrogen circuit test system, a cooling system shared by both, and an FCU that controls each electrical component; an auxiliary cooling circuit is connected to the cooling system; the auxiliary cooling circuit includes an expansion tank with a pressure cap, and the expansion tank is used to add water, drain water and vent air.

[0015] The air circuit test system includes an air filter, an air flow meter, an air compressor test piece, a temperature / pressure sensor, an intercooler test piece, a throttle valve, and a switch valve one connected in sequence. The air compressor test piece and the intercooler test piece are connected on one hand by a manual switch valve, and on the other hand by a switch valve two and a thermostat one. The outlet end of the intercooler test piece is connected to a switch valve three.

[0016] The hydrogen circuit test system includes a switching valve six and a gas preheater connected in sequence; the gas preheater's outlet one is connected in sequence to a proportional valve, a gas cooler, a hydrogen flow meter one, and a hydrogen pump test piece; the outlet two is connected in sequence to an ejector test piece, a hydrogen flow meter two, and a switching valve seven; the outlet one of the hydrogen pump test piece is connected to the pipeline between the proportional valve and the gas cooler; the outlet two is connected to the tailpipe pipeline of switching valve seven through switching valve nine; the outlet three is connected to thermostat two through switching valve four; a switching valve eight and a hydrogen flow meter three are also connected between the ejector test piece and the hydrogen flow meter two; the gas preheater, PTC, water pump two, and temperature sensor are connected in sequence to form a gas temperature regulation cycle.

[0017] The cooling system includes a radiator; the outlet of the radiator is connected in sequence to a water pump, a cooling flow meter, a thermostat, a switch valve, and a hydrogen pump test piece; the inlet of the radiator is connected to the intercooler test piece via a switch valve. The outlet of the gas cooler is connected to the pipeline between the radiator and the switch valve, and the inlet of the gas cooler is connected to the pipeline between the radiator and the switch valve. A manual switch valve is connected to the pipeline between the air compressor test piece and the intercooler test piece, on the side closer to the intercooler test piece.

[0018] The auxiliary cooling circuit includes a water outlet valve A on the pipeline connecting the expansion tank to the radiator and water pump one, a water outlet valve B on the pipeline connecting the expansion tank to the PTC and water pump two, a water inlet valve C on the pipeline connecting the expansion tank to water pump two and the temperature sensor, a water inlet valve D connecting the water inlet valve and the pipeline between the switch valve four and the hydrogen pump under test, and a water inlet valve E connecting the expansion tank and the radiator.

[0019] The outlet valve a of thermostat one is connected to switch valve two, the outlet valve b is connected to the intercooler test unit, and the inlet valve is connected to the pipeline between the cooling flow meter and switch valve five.

[0020] The outlet valve a of thermostat two is connected to the gas cooler, the outlet valve b is connected to the pipeline between the radiator and switch three, and the inlet valve is connected to the gas cooler.

[0021] The pressure cap of the expansion tank is connected to the tank body by a spring. When the pressure exceeds a certain force, the pressure will compress the spring, and the cap will be pushed up, allowing the internal and external air pressures to connect. After the connection is made, the air pressure inside the tank decreases, and the cap will retract to its original position by the spring, sealing the tank again.

[0022] Before starting the equipment, open all valves (thermostat 1, thermostat 2, on / off valve 2, manual on / off valve, on / off valve 3, on / off valve 4, and on / off valve 5) to facilitate the flow of cooling water to all parts of the equipment. The cooling water for the equipment is injected from the expansion tank. Figure 1 The dashed line represents the auxiliary cooling circuit. Circles A, B, C, and D mark the intersections between the main cooling system and the auxiliary cooling circuit, allowing water to flow between the two circuits. The auxiliary cooling circuit uses thinner pipes, while the main cooling system uses thicker pipes.

[0023] The specific flow is as follows: After water is added to the expansion tank, it flows into the common cooling system through the auxiliary valve A. There is also an auxiliary loop on valve A, namely valve B, which injects cooling water into the common cooling system loop of pump two. As water is continuously added, pump two will return to the expansion tank from the auxiliary loop at point C, and similarly at point D. Auxiliary loops C and D merge and flow back to the expansion tank. The auxiliary pipe at point E connects directly to the auxiliary pipe in the radiator, allowing cooling water to flow back to the expansion tank from point E. During equipment operation, the common cooling system and auxiliary cooling loops continuously circulate. Some cooling water may be lost during prolonged use or when replacing parts; this can be replenished directly from the expansion tank.

[0024] Cooling water is injected into the equipment through the cover on top of the expansion tank. The cooling water flows to the public cooling system through the auxiliary cooling circuit, ensuring that all pipes and BOP components inside the equipment are filled with cooling water. At this time, there is still a large amount of gas inside the equipment. This gas needs to be discharged before testing. Excessive gas will cause the cooling water temperature to be insufficient, failing to effectively reduce the temperature of the BOP components. In severe cases, it may cause the BOP components to stop operating, or even trigger an overheating alarm, preventing the equipment from working properly.

[0025] At this time, all valves remain open, with only water pumps one and two activated to allow the cooling water to circulate throughout the public cooling system. Gases in the equipment pipes and components are carried back to the expansion tank via the auxiliary cooling circuit as the cooling water flows, and then discharged through the opening at the top of the expansion tank.

[0026] After most of the gas has been expelled, only a small amount of gas remains in each circuit of the equipment. At this point, close the lid of the expansion tank (here, a common water tank that can be opened according to the pressure is selected), and return all valves to their initial state.

[0027] When testing the BOP performance of the air circuit: only the air circuit test system needs to be activated. The FCU controls the opening of the throttle and the first switching valve to adjust the intake air volume and pressure. Air enters, passes through the air filter, air flow meter, the air compressor under test, temperature / pressure sensor, the intercooler under test, and is finally discharged.

[0028] At this time, the cooling circuit is also working. With switch valve five closed, only the cooling circuit of the air circuit is working. The coolant flows through water pump one and the cooling flow meter, and is controlled by thermostat one to the air compressor and intercooler test components in the air circuit.

[0029] The cooling water flowing through the two test components is controlled by valves at terminals a and b of thermostat one. Switch valve two provides auxiliary control over the cooling water flowing into the air compressor test component, and switch valve three provides auxiliary control over the cooling water flowing out of the intercooler test component. Adjusting valves a and b controls the flow rate and volume of the cooling water. The cooling water cools the two test components; a faster flow rate results in a faster and lower temperature drop, while a slower flow rate results in a smaller temperature reduction. Simultaneously, closing the manual switch valves blocks the flow of cooling water from the air compressor test component to the intercooler test component, preventing further cooling water flow. Therefore, the manual switch valves can also control the cooling water flow to pass only through either the air compressor test component or the intercooler test component, without affecting the other test component.

[0030] When only the air compressor performance is tested: valve a of thermostat one is open, valve b is closed, switch valve two is open, and manual switch valve is closed.

[0031] When only the intercooler performance is tested: valve b of thermostat 1 is open, valve a is closed, switch valve 3 is open, and manual switch valve is closed.

[0032] Finally, the cooling water flows into the radiator, where it dissipates heat. After cooling down, the water flows back to the pump for reuse.

[0033] When the manual switch valve is closed, adjusting valve a of thermostat one and closing valve b of thermostat one will allow cooling water to cool only the circuit of the air compressor test component. Adjusting valve b of thermostat one and closing valve a will allow cooling water to flow only through the circuit of the intercooler test component. Opening the manual switch valve can also provide auxiliary temperature control for the circuits of the air compressor test component and the intercooler test component. For cases with specific temperature requirements, the opening of valves a and b can be adjusted to control the flow rate and volume of the cooling water, thereby stabilizing the temperature around a certain value to achieve the required experimental effect.

[0034] When it is necessary to test the BOP performance of the hydrogen circuit: simply start the hydrogen circuit test system, and the FCU will control the opening of the switching valve and the proportional valve in real time to adjust the intake rate and pressure of the hydrogen circuit.

[0035] Hydrogen gas passes through switch valve six, is heated by the gas preheater, passes through the proportional valve, then through the gas cooler and hydrogen flow meter one to reach the hydrogen pump. It then returns to the end of the proportional valve. When the gas reaches a certain temperature, the proportional valve closes, forming a cycle. When it is necessary to adjust the pressure within the cycle, the FCU controls switch valve nine to regulate the pressure within the cycle for tail discharge.

[0036] At this time, the cooling circuit is working simultaneously. The FCU controls the closure of thermostat one leading to the air path. The coolant flows through water pump one, cooling flow meter, and then through switch valve five to the hydrogen pump under test. After being regulated by switch valve four, it reaches thermostat two. The a and b valves of thermostat two control whether it flows through the gas cooler. Finally, it flows back to the radiator for heat dissipation and returns to start a new cycle.

[0037] The cooling water flow rate and volume in the hydrogen circuit are controlled by valves a and b of thermostat two. If only the hydrogen pump under test needs cooling control, valve a is closed; if the gas cooler also needs cooling control, valve b is closed. If there are special temperature requirements, the size of valves a and b is controlled to regulate the temperature of the hydrogen pump under test and the gas cooler.

[0038] To realistically simulate the hydrogen inlet temperature, a PTC (Potential Temperature Coefficient) is added near the gas preheater. Cooling water flows into the gas preheater circulation loop and is filled by pump two. The PTC heats the cooling water, which then circulates through pump two before flowing back into the gas preheater. The gas preheater uses this heated water to heat the incoming hydrogen. After heating the hydrogen, the cooling water temperature decreases, at which point it recirculates through the PTC and is heated again, thus achieving the function of heating the inlet hydrogen and reusing the cooling water.

[0039] Temperature is monitored by a temperature sensor in the loop. The PTC heating temperature and the speed of water pump two are adjusted in real time according to the simulated conditions to achieve the function of simulating hydrogen inlet temperature. When a decrease in hydrogen temperature is needed, the PTC heating temperature is lowered and the speed of water pump two is increased; when a slight increase in hydrogen temperature is needed, the PTC heating temperature is increased and the speed of water pump two is decreased. The PTC, water pump two, thermostat one, thermostat two, and various switching valves in the cooling loop are all controlled by the FCU.

[0040] If the BOP performance of both the air circuit and the hydrogen circuit needs to be tested, controlling thermostat one and switching valve five will enable both cooling circuits to start working.

[0041] When testing the BOP performance of the ejector circuit: the FCU controls the opening of the regulating valve seven to adjust the exhaust volume and pressure within the channel. Hydrogen gas reaches the ejector under test via the gas preheater, and then passes through hydrogen flow meter two for tailing. Most of the hydrogen gas can be recycled. By closing the regulating valve seven, the hydrogen gas exiting the ejector under test can be regulated by the regulating valve eight, pass through hydrogen flow meter three, and return to the ejector for reuse.

[0042] During testing in each circuit, the initial residual gas is gradually carried into the expansion tank as the test proceeds through the auxiliary cooling water circuit. Once the gas pressure reaches the set value, the valve cover on top of the tank opens, releasing excess gas. After the gas is released and the pressure is less than or equal to the set pressure, the top cover closes again. The pressure valve in the expansion tank ensures smoother cooling water circulation and also guarantees the required internal and external pressure difference during some BOP component tests.

[0043] When replacing BOP components or equipment parts later, a small amount of cooling water will be lost, and some gas will enter the equipment. Repeat the previous steps again: before testing, open all valves in the equipment, turn water pump one and water pump two to circulate the cooling circuit and expel excess gas. The remaining small amount of gas will also be slowly discharged during the circuit test.

[0044] During testing, data from all components is transmitted to the FCU for analysis, enabling the FCU to control the size of various valves and balance pressure, flow, and on / off states within the circuit. The FCU is an integrated control unit that can receive and send commands in real time. This patent uses commercially available and readily available FCUs; before use, we only need to edit the commands and re-flash the program in the FCU suitable for the product.

[0045] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A BOP test bench with a cooling circuit capable of safe venting, characterized in that, This includes an air circuit test system, a hydrogen circuit test system, a cooling system shared by both, and an FCU that controls each electrical component; An auxiliary cooling circuit is connected to the cooling system; the auxiliary cooling circuit includes an expansion tank with a pressure cap, and the expansion tank is used to add water, drain water and vent air.

2. The BOP test bench with safe venting capability for cooling circuits according to claim 1, characterized in that, The air circuit test system includes an air filter, an air flow meter, an air compressor test piece, a temperature / pressure sensor, an intercooler test piece, a throttle valve, and a switch valve one connected in sequence. The air compressor test piece and the intercooler test piece are connected on one hand by a manual switch valve, and on the other hand by a switch valve two and a thermostat one. The outlet end of the intercooler test piece is connected to a switch valve three.

3. The BOP test bench with safe venting capability for cooling circuits according to claim 2, characterized in that, The hydrogen circuit test system includes a switching valve six and a gas preheater connected in sequence; the gas preheater's outlet one is connected in sequence to a proportional valve, a gas cooler, a hydrogen flow meter one, and a hydrogen pump test piece; the outlet two is connected in sequence to an ejector test piece, a hydrogen flow meter two, and a switching valve seven; the outlet one of the hydrogen pump test piece is connected to the pipeline between the proportional valve and the gas cooler; the outlet two is connected to the tailpipe pipeline of switching valve seven through switching valve nine; the outlet three is connected to thermostat two through switching valve four; a switching valve eight and a hydrogen flow meter three are also connected between the ejector test piece and the hydrogen flow meter two; the gas preheater, PTC, water pump two, and temperature sensor are connected in sequence to form a gas temperature regulation cycle.

4. The BOP test bench with safe venting capability for cooling circuits according to claim 3, characterized in that, The cooling system includes a radiator; the outlet of the radiator is connected in sequence to a water pump, a cooling flow meter, a thermostat, a switch valve, and a hydrogen pump test piece; the inlet of the radiator is connected to the intercooler test piece via a switch valve. The outlet of the gas cooler is connected to the pipeline between the radiator and the switch valve, and the inlet of the gas cooler is connected to the pipeline between the radiator and the switch valve. A manual switch valve is connected to the pipeline between the air compressor test piece and the intercooler test piece, on the side closer to the intercooler test piece.

5. The BOP test bench with safe venting capability for cooling circuits according to claim 4, characterized in that, The auxiliary cooling circuit includes a water outlet valve A on the pipeline connecting the expansion tank to the radiator and water pump one, a water outlet valve B on the pipeline connecting the expansion tank to the PTC and water pump two, a water inlet valve C on the pipeline connecting the expansion tank to water pump two and the temperature sensor, a water inlet valve D connecting the water inlet valve and the pipeline between the switch valve four and the hydrogen pump under test, and a water inlet valve E connecting the expansion tank and the radiator.

6. The BOP test bench with safe venting capability for cooling circuits according to claim 4, characterized in that, The outlet valve a of thermostat one is connected to switch valve two, the outlet valve b is connected to the intercooler test unit, and the inlet valve is connected to the pipeline between the cooling flow meter and switch valve five.

7. The BOP test bench with safe venting capability for the cooling circuit according to claim 4, characterized in that, The outlet valve a of thermostat two is connected to the gas cooler, the outlet valve b is connected to the pipeline between the radiator and switch three, and the inlet valve is connected to the gas cooler.

8. The BOP test bench with safe venting capability for cooling circuits according to claim 5, characterized in that, The pressure cover of the expansion tank is connected to the tank body by a spring.

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