Fuel cell and electric pile sealing performance online detection method thereof

Abstract

The invention provides a fuel cell. The invention further provides an on-line detection method for the electric pile airtightness based on adjustment of the rotating speed of the air compressor, and the change condition of the insulation resistance is monitored by adjusting the rotating speed of the air compressor, so that the electric pile airtightness is judged. The invention further provides an on-line stack airtightness detection method based on water pump rotating speed adjustment, and the change condition of the insulation resistance is monitored by adjusting the water pump rotating speed, so that the stack airtightness is judged. The invention also provides an on-line detection method for the sealing performance of the electric pile based on adjustment of the output current of the electric pile, and the air tightness of the electric pile is judged by adjusting the current of the electric pile to monitor the change condition of the insulation resistance.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and specifically to an online detection method for the sealing performance of a fuel cell and its stack. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a power generation device that converts the chemical energy of hydrogen into external electrical energy through the action of a catalyst. It boasts advantages such as zero emissions, high efficiency, and low noise, and has broad application prospects and a clear advantage in the transportation sector, especially in heavy-duty and long-distance transport. A fuel cell system includes a stack, air system, hydrogen system, cooling system, electrical system, and corresponding control system.

[0003] Fuel cell stacks typically consist of hundreds of individual cells connected in series. During operation, the output voltage of each cell remains within a certain normal range. When early sealing issues arise in the stack, the stack performance does not show significant changes, making accurate diagnosis impossible through individual cell voltage or voltage deviation. Therefore, there is an urgent need for a method to identify early signs of poor stack sealing, preventing further deterioration of stack performance and subsequent damage to individual cells. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a fuel cell comprising: a stack, an air module, a hydrogen module, a voltage monitor, a boost DC / DC converter, a distribution box, a power battery, an insulation resistance detection module, a controller, and a cooling module. The fuel cell stack is used to realize the chemical reaction between hydrogen and oxygen and output electrical energy; The air module is used to provide oxygen to the fuel cell stack by driving air through an air compressor; The hydrogen module is used to supply hydrogen to the fuel cell stack; The voltage detector is used to collect the voltage of each individual cell in the fuel cell stack; The boost DC / DC converter (Direct Current to Direct Current Boost Converter) is used to boost and regulate the electrical energy output from the fuel cell stack, and to collect the fuel cell stack output current; The distribution box is used to distribute the boosted and stabilized electrical energy to various components of the vehicle. The power battery is used to receive the electrical energy distributed by the distribution box and to supply power to various components of the vehicle as an auxiliary power source. The insulation resistance detection module is used to collect the insulation resistance value of the high-voltage circuit of the whole vehicle in real time; The cooling module is used to cool the fuel cell stack by driving coolant with a water pump. The controller is used to control the air compressor speed of the air module, the water pump speed of the cooling module, and to set the output voltage of the boost DC / DC converter to control the output current of the fuel cell stack.

[0005] Furthermore, the stack is composed of multiple individual cells connected in series; The air input terminal K1 of the air module is connected to the air inlet terminal D1 of the fuel cell stack, and the air output terminal K2 of the air module is connected to the air outlet terminal D2 of the fuel cell stack. The hydrogen input terminal H1 of the hydrogen module is connected to the hydrogen inlet terminal D3 of the fuel cell stack, and the hydrogen output terminal H2 of the hydrogen module is connected to the hydrogen outlet terminal D4 of the fuel cell stack. Each positive sampling terminal and each negative sampling terminal of the voltage detector are connected to the positive and negative terminals of the corresponding single cell of the fuel cell stack, respectively. The low-voltage input terminal S1 of the boost DC / DC converter is connected to the output bus terminal D5 of the fuel cell stack. The input terminal P1 of the distribution box is connected to the high-voltage output terminal S2 of the boost DC / DC converter; The positive terminal L1 of the power battery is connected to the positive busbar P2 of the distribution box, and the negative terminal L2 of the power battery is connected to the negative busbar P3 of the distribution box. The negative detection terminal J1 of the insulation resistance detection module is connected to the negative sampling terminal L3 of the power battery, the positive detection terminal J2 of the insulation resistance detection module is connected to the positive sampling terminal L4 of the power battery, and the reference ground terminal J3 of the insulation resistance detection module is connected to the vehicle frame. The coolant inlet Y1 of the cooling module is connected to the coolant inlet D6 of the fuel cell stack, and the coolant outlet Y2 of the cooling module is connected to the coolant outlet D7 of the fuel cell stack. The air compressor control terminal C1 of the controller is connected to the controlled terminal K3 of the air compressor of the air module; the water pump control terminal C2 of the controller is connected to the controlled terminal Y3 of the water pump of the cooling module; the DC / DC communication terminal C3 of the controller is connected to the controlled terminal S3 of the boost DC / DC converter; and the voltage acquisition terminal C4 of the controller is connected to the voltage communication terminal X1 of the voltage detector.

[0006] A method for online detection of fuel cell stack sealing performance based on adjusting air compressor speed includes: When the air compressor speed of the air module is 0, the first insulation resistance value of the high-voltage circuit of the whole vehicle is collected. The air compressor speed of the air module is set to k1, and the second insulation resistance value of the high-voltage circuit of the whole vehicle is collected again. Based on the standard curve of insulation resistance versus air compressor speed, the first insulation resistance reference value when the air compressor speed is 0 and the second insulation resistance reference value when the air compressor speed is k1 are obtained. The difference between the first insulation resistance value and the first insulation resistance reference value is obtained to get dM1, and the difference between the second insulation resistance value and the second insulation resistance reference value is obtained to get dM2. If dM2≤dM1, the fuel cell stack sealing is normal; if dM2>dM1, the fuel cell stack sealing is abnormal.

[0007] Furthermore, both the first insulation resistance value and the second insulation resistance value are acquired through an insulation resistance detection module; The speed of the air compressor in the air module is adjusted by a controller.

[0008] A method for online detection of fuel cell stack sealing performance based on regulating the speed of the water pump includes: When the water pump speed of the cooling module is 0, the third insulation resistance value of the high-voltage circuit of the whole vehicle is collected. When the water pump speed of the cooling module is set to n1, the fourth insulation resistance value of the high-voltage circuit of the whole vehicle is collected again. Based on the standard curve of insulation resistance versus air compressor speed, the reference value of the third insulation resistance when the pump speed is 0 and the reference value of the fourth insulation resistance when the pump speed is k1 are obtained. The difference between the third insulation resistance value and the reference value is obtained to get dM3. The difference between the fourth insulation resistance value and the reference value is obtained to get dM4. If dM4≤dM3, the fuel cell stack sealing is normal; if dM4>dM3, the fuel cell stack sealing is abnormal.

[0009] Furthermore, both the third and fourth insulation resistance values ​​are acquired through an insulation resistance detection module. The speed of the water pump in the cooling module is adjusted by a controller.

[0010] An online method for detecting the sealing performance of a fuel cell stack based on adjusting the stack output current includes: When the fuel cell output current is 0, the fifth insulation resistance value of the high-voltage circuit of the whole vehicle is collected. When the fuel cell output current is A1, the sixth insulation resistance value of the high-voltage circuit of the whole vehicle is collected again. Based on the standard curve of insulation resistance versus air compressor speed, the fifth insulation resistance reference value when the stack output current is 0 and the sixth insulation resistance reference value when the stack output current is a1 are obtained. The difference between the fifth insulation resistance value and the fifth insulation resistance reference value is obtained to get dM5. The difference between the sixth insulation resistance value and the sixth insulation resistance reference value is obtained to get dM6. If dM6≤dM5, the fuel cell stack sealing is normal; if dM6>dM5, the fuel cell stack sealing is abnormal.

[0011] Furthermore, both the fifth and sixth insulation resistance values ​​are acquired through an insulation resistance detection module. The output current of the fuel cell stack is controlled by adjusting the output voltage of the boost DC / DC21 via a controller.

[0012] A computer-readable medium storing a computer program, which, when executed, performs the above-described online fuel cell stack sealing test method based on adjusting the air compressor speed, or the above-described online fuel cell stack sealing test method based on adjusting the water pump speed, or the above-described online fuel cell stack sealing test method based on adjusting the fuel cell stack output current.

[0013] A computer program product includes a computer program / instructions that, when executed by a processor, implement the above-mentioned online detection method for fuel cell stack sealing based on adjusting the speed of an air compressor, or the above-mentioned online detection method for fuel cell stack sealing based on adjusting the speed of a water pump, or the above-mentioned online detection method for fuel cell stack sealing based on adjusting the output current of the fuel cell stack.

[0014] The beneficial effects of this invention are as follows: 1. This invention, by monitoring changes in insulation resistance, can detect minor anomalies in the stack's sealing in a timely manner, preventing the problem from escalating into individual cell damage or system failure. Existing technologies cannot diagnose sealing issues in the early stages through changes in individual cell voltage, while this invention utilizes insulation resistance as a sensitive indicator, significantly improving early warning capabilities.

[0015] 2. This invention provides three complementary detection methods (based on adjusting the air compressor speed, water pump speed, and fuel cell stack output current). Each method achieves non-invasive detection through simple adjustment of system parameters, without requiring disassembly of the fuel cell stack or shutdown. The coexistence of the three methods enables the fuel cell to detect different sealing failure scenarios, targeting three leakage mechanisms: air circuit, coolant circuit, and electrochemical circuit, respectively. This avoids the limitations of a single method and improves the robustness and reliability of the detection.

[0016] 3. This invention effectively eliminates interference from external factors (such as changes in coolant conductivity) by comparing differences rather than absolute insulation resistance values. Specifically, the reference value is derived from a standard curve calibrated in the laboratory (insulation resistance versus air compressor speed / water pump speed / fuel cell stack current curve), and is combined with real-time difference calculations to ensure that the judgment logic is triggered only when a sealing problem occurs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the fuel cell principle of the present invention.

[0018] Figure 2 The insulation resistance curves are shown for when the fuel cell stack of a vehicle has normal sealing and when the stack has abnormal sealing.

[0019] Figure 3 The insulation resistance curves are shown for when the fuel cell stack of a vehicle has normal sealing and when the stack has abnormal sealing.

[0020] Figure 4 The insulation resistance curves are shown for when the fuel cell stack of a vehicle has normal sealing and when the stack has abnormal sealing.

[0021] Figure 5 This is a flowchart of an online detection method for fuel cell stack sealing based on adjusting the air compressor speed.

[0022] Figure 6 This is a flowchart of an online detection method for fuel cell stack sealing based on adjusting the speed of the water pump.

[0023] Figure 7 This is a flowchart of an online detection method for fuel cell stack sealing based on adjusting the speed of the water pump. Detailed Implementation

[0024] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0025] Example 1 A fuel cell, reference Figure 1 It includes: fuel cell stack 1, air module 2, hydrogen module 3, voltage monitor 4, boost DC / DC converter 5, distribution box 6, power battery 7, insulation resistance detection module 8, controller 9, and cooling module 10.

[0026] The fuel cell stack 1 is composed of multiple single cells connected in series. The fuel cell stack 1 is used to realize the chemical reaction between hydrogen and oxygen and output electrical energy.

[0027] The air input terminal K1 of the air module 2 is connected to the air inlet terminal D1 of the fuel cell stack 1, and the air output terminal K2 of the air module 2 is connected to the air outlet terminal D2 of the fuel cell stack 1. The air module 2 includes an air flow meter 21, an air compressor 22, and a back pressure valve 23. The air flow meter 21 and the air compressor 22 are installed on the air inlet pipe, and the back pressure valve 23 is installed on the air outlet pipe. The air flow meter 21 collects the flow rate of the air inlet pipe. The air compressor 22 is used to provide the air flow rate and pressure required for the operation of the fuel cell stack 1. The back pressure valve 23 is used to adjust the back pressure of the air outlet pipe. The air module 2 is used to provide oxygen to the fuel cell stack 1 by driving air through the air compressor 22.

[0028] The hydrogen input terminal H1 of the hydrogen module 3 is connected to the hydrogen inlet terminal D3 of the fuel cell stack 1, and the hydrogen output terminal H2 of the hydrogen module 3 is connected to the hydrogen outlet terminal D4 of the fuel cell stack 1. The hydrogen module 3 is used to supply hydrogen to the fuel cell stack 1. The other end of the hydrogen input terminal H1 is connected to a hydrogen storage device.

[0029] The positive and negative sampling terminals of the voltage detector 4 are connected to the positive and negative terminals of the corresponding single cell of the fuel cell stack 1, respectively. The voltage detector 4 is used to collect the voltage of each single cell in the fuel cell stack 1 and send it to the controller 9.

[0030] The low-voltage input terminal S1 of the boost DC / DC5 is connected to the output bus terminal D5 of the fuel cell stack 1. The boost DC / DC5 is used to boost and stabilize the electrical energy output by the fuel cell stack 1 and to collect the output current of the fuel cell stack. The input terminal P1 of the power distribution box 6 is connected to the high-voltage output terminal S2 of the boost DC / DC 5, and each output terminal Pn of the power distribution box 6 is connected to the corresponding component of the vehicle. The power distribution box 6 is used to distribute the boosted and regulated electrical energy to various components of the vehicle, such as the power battery 7, drive motor, vehicle accessories, and fuel cell accessory electrical devices.

[0031] The positive terminal L1 of the power battery 7 is connected to the positive busbar P2 of the distribution box 6, and the negative terminal L2 of the power battery 7 is connected to the negative busbar P3 of the distribution box 6. The power battery 7 is used to receive the electrical energy distributed by the distribution box 6 and to provide power to various components of the vehicle as an auxiliary power source. The power battery 7 can provide electrical energy to the fuel cell system accessories during fuel cell startup and shutdown.

[0032] The negative terminal J1 of the insulation resistance detection module 8 is connected to the negative sampling terminal L3 of the power battery 7, and the positive terminal J2 of the insulation resistance detection module 8 is connected to the positive sampling terminal L4 of the power battery 7. The reference ground terminal J3 of the insulation resistance detection module 8 is connected to the vehicle frame. The insulation resistance detection module 8 is used to collect the insulation resistance value of the high-voltage circuit of the entire vehicle in real time. The positive and negative terminals of the power battery 7 are connected to the distribution box 6, forming the core component of the high-voltage circuit of the entire vehicle. The insulation resistance detection module needs to monitor the insulation status of the entire high-voltage circuit, and the power battery, as one of the core components of the high-voltage system, can be connected to comprehensively detect the insulation status of the high-voltage bus. As the main energy storage device, the insulation status of the power battery 7 directly affects the safety of the entire vehicle. When the fuel cell system is working, the power battery 7 will operate in parallel with the output of the fuel cell stack 1. At this time, detecting the insulation resistance at the power battery terminal can simultaneously reflect the insulation status of the fuel cell stack and the battery. The insulation resistance detection module 8 is existing technology. For its specific structure, please refer to Chinese patent CN118431512A, which describes an insulation detection method, device and storage medium for a fuel cell system. This method is used to monitor the insulation resistance between the high-voltage circuit of the vehicle (including high-voltage components such as the stack output bus, power battery and distribution box) and the vehicle frame ground. By injecting a low-frequency AC signal or DC bias voltage into the high-voltage circuit, the leakage current between the vehicle frame ground and the positive / negative poles is measured, and the insulation resistance is calculated according to Ohm's law.

[0033] The coolant inlet Y1 of the cooling module 10 is connected to the coolant inlet D6 of the fuel cell stack 1, and the coolant outlet Y2 of the cooling module 10 is connected to the coolant outlet D7 of the fuel cell stack 1. The cooling module 10 is used to cool the fuel cell stack 1 by driving the coolant through the water pump 101. The cooling module 10 includes a water pump 101, an inlet temperature and pressure sensor 105, an outlet temperature and pressure sensor 104, a temperature control valve 103, and a radiator fan assembly 102. The coolant flow direction in the cooling circuit is: water pump 101, inlet temperature and pressure sensor 105, fuel cell stack 1, outlet temperature and pressure sensor 104, and temperature control valve 103. The first outlet of the temperature control valve 103 flows to the water pump 101 to form a small loop, and the second outlet of the temperature control valve 103 flows to the radiator 102 to form a large loop. The function of water pump 101 is to realize the circulation of coolant in the cooling circuit. The function of temperature and pressure sensors 105 and 104 is to detect the temperature and pressure of coolant entering and leaving the reactor. The function of temperature control valve 103 is to realize the switching between large and small circulation. The function of radiator fan assembly 102 is to exchange heat between the coolant and the air to reduce the coolant temperature.

[0034] The air compressor control terminal C1 of the controller 9 is connected to the controlled terminal K3 of the air compressor 22 of the air module 2. The water pump control terminal C2 of the controller 9 is connected to the controlled terminal Y3 of the water pump 101 of the cooling module 10. The DC / DC communication terminal C3 of the controller 9 is connected to the controlled terminal S3 of the boost DC / DC5. The voltage acquisition terminal C4 of the controller 9 is connected to the voltage communication terminal X1 of the voltage detector 4. The controller 9 is used to control the speed of the air compressor 22 of the air module 2, control the speed of the water pump 101 of the cooling module 10, and set the output voltage of the boost DC / DC5 to control the output current of the fuel cell stack 1. The controller 9 is a 32-bit automotive-grade MCU. The DC / DC communication terminal C3 is a CAN controller (Controller Area Network Controller). The air compressor / water pump control is achieved through PWM output (Pulse Width Modulation Output). The voltage acquisition terminal C4 is an ADC acquisition. In fuel cell systems, the stack output current is strongly correlated with the load demand. When the boost DC / DC converter increases the output voltage, it is equivalent to increasing the equivalent load impedance at the stack end. If the boost DC / DC output voltage increases and the load power demand remains unchanged, the stack output current needs to increase accordingly to maintain power balance. Therefore, the controller can indirectly control the stack output current by adjusting the boost DC / DC output voltage.

[0035] Example 2 like Figure 5 For control process S1, an online detection method for fuel cell stack sealing based on adjusting air compressor speed includes: The high-voltage contactors of the vehicle and fuel cell system close, completing the high-voltage power-on process and ensuring the entire high-voltage circuit is unobstructed. When the air compressor 22 of air module 2 is at 0 speed, the first insulation resistance value of the vehicle's high-voltage circuit is collected. Then, with the air compressor 22 speed of air module 2 set to k1, the second insulation resistance value of the vehicle's high-voltage circuit is collected again. Both the first and second insulation resistance values ​​are collected by the insulation resistance detection module 8, and the speed of the air compressor 22 of air module 2 is adjusted by the controller 9.

[0036] Based on the standard curve of insulation resistance versus air compressor speed, the first insulation resistance reference value and the second insulation resistance reference value are obtained in the laboratory through data calibration. The first insulation resistance reference value and the second insulation resistance reference value are obtained when the air compressor speed is 0 and k1, respectively. The difference between the first insulation resistance value and the first insulation resistance reference value is obtained to get dM1, and the difference between the second insulation resistance value and the second insulation resistance reference value is obtained to get dM2.

[0037] If dM2≤dM1, then the sealing performance of fuel cell stack 1 is normal. This is because as the air compressor speed increases, the airflow increases, and the air pressure entering the stack increases. As the internal air pressure of the fuel cell stack increases, the air pressure will cause some compression inside the stack, but it does not increase the internal leakage flow of the fuel cell stack, nor does it significantly reduce the insulation resistance value of the fuel cell stack. Therefore, the sealing performance of the fuel cell stack is judged to be normal.

[0038] If dM2 > dM1, then the sealing performance of fuel cell stack 1 is abnormal. This is because as the air compressor speed increases, the airflow increases, and the air pressure entering the stack increases. As the internal air pressure of the fuel cell stack increases, the air pressure will cause a certain amount of compression inside the stack and increase the internal leakage flow, significantly reducing the insulation resistance value of the fuel cell stack, thus determining that the sealing performance of the fuel cell stack is abnormal.

[0039] like Figure 2 The graph shows the insulation resistance curves for a vehicle fuel cell stack with normal sealing and those with abnormal sealing. The horizontal axis represents the air compressor speed, and the vertical axis represents the insulation resistance value. As the air compressor speed increases, the insulation resistance of a normally sealed stack decreases slightly, while the decrease is greater for an abnormally sealed stack. This is because increasing the air compressor speed increases the airflow and the air pressure entering the stack. When a slight abnormality occurs in the stack's sealing, the increased internal air pressure causes compression within the stack, increasing leakage and thus reducing the insulation resistance. dM represents the difference between the insulation resistance of an abnormally sealed stack and that of a normal stack. dM1 represents the insulation resistance difference at an air compressor speed of 0, and dM2 represents the difference at an air compressor speed of k1. An increase in dM1 may indicate a decrease in coolant conductivity; therefore, the difference between dM2 and dM1 should be used as the evaluation factor to avoid misjudgments due to changes in coolant conductivity.

[0040] By adjusting the air compressor speed to trigger changes in the internal air pressure of the fuel cell stack, and utilizing the difference in insulation resistance, abnormal sealing can be detected. This method is far more sensitive to micro-leakage in the gas circuit, such as leakage through the membrane electrode pores, than traditional voltage monitoring methods.

[0041] Example 3 like Figure 6 For control process S2, an online detection method for fuel cell stack sealing based on adjusting the speed of the regulating water pump includes: The high-voltage contactors of the vehicle and fuel cell system close, completing the high-voltage power-on process and ensuring the entire high-voltage circuit is unobstructed. When the water pump 101 of the cooling module 10 is rotating at 0, the third insulation resistance value of the vehicle's high-voltage circuit is collected. Then, the water pump 101's rotational speed is set to n1, and the fourth insulation resistance value of the vehicle's high-voltage circuit is collected again. Both the third and fourth insulation resistance values ​​are collected by the insulation resistance detection module 8, and the rotational speed of the water pump 101 of the cooling module 10 is adjusted by the controller 9.

[0042] Based on the standard curve of insulation resistance versus air compressor speed, the third insulation resistance reference value when the speed of water pump 101 is 0 and the fourth insulation resistance reference value when the speed of water pump 101 is n1 are obtained. The difference between the third insulation resistance value and the third insulation resistance reference value is obtained to get dM3. The difference between the fourth insulation resistance value and the fourth insulation resistance reference value is obtained to get dM4.

[0043] If dM4 ≤ dM3, then the sealing performance of fuel cell stack 1 is normal. This is because as the pump speed increases, the pump flow rate increases, and the pressure of the pump entering the stack increases. As the internal coolant pressure of the fuel cell stack increases, the coolant air pressure will cause some compression inside the stack. However, this does not increase the internal leakage flow rate of the fuel cell stack, nor does it significantly reduce the insulation resistance value of the fuel cell stack. Therefore, the sealing performance of the fuel cell stack is judged to be normal.

[0044] If dM4 > dM3, then the sealing performance of fuel cell stack 1 is abnormal. This is because as the pump speed increases, the pump flow rate increases, and the pressure of the pump entering the stack increases. As the internal coolant pressure of the fuel cell stack increases, the coolant air pressure will cause a certain amount of compression inside the fuel cell stack, and increase the internal leakage flow, significantly reducing the insulation resistance value of the fuel cell stack, thus determining that the fuel cell stack sealing performance is abnormal.

[0045] like Figure 3 The graph shows the insulation resistance curves for a vehicle fuel cell stack with normal sealing and those with abnormal sealing. The horizontal axis represents the water pump speed, and the vertical axis represents the insulation resistance value. As the water pump speed increases, the insulation resistance of a normally sealed stack decreases slightly, while the decrease is greater for an abnormally sealed stack. This is because increasing the water pump speed increases the pressure in the coolant circuit and the pressure of the coolant entering the stack. When a slight abnormality occurs in the stack's sealing, the increased internal coolant pressure causes some compression within the stack, increasing the internal leakage flow and thus reducing the insulation resistance. dM represents the difference between the insulation resistance of an abnormally sealed stack and that of a normal stack. dM3 represents the insulation resistance difference when the water pump speed is 0, and dM4 represents the insulation resistance difference when the air compressor speed is n1. An increase in dM3 may indicate a decrease in coolant conductivity; therefore, the difference between dM4 and dM3 should be used as the evaluation factor to avoid misjudgments due to changes in coolant conductivity.

[0046] By adjusting the water pump speed to trigger changes in the internal cooling hydraulic pressure of the fuel cell stack, and utilizing the difference in insulation resistance, abnormal sealing can be detected. This method is far more sensitive to micro-leakage in the coolant circuit than traditional voltage monitoring methods.

[0047] Example 4 like Figure 7 For control process S3, an online detection method for fuel cell stack sealing based on adjusting the fuel cell stack output current includes: The high-voltage contactors of the vehicle and fuel cell system close, completing the high-voltage power-on process and ensuring the entire high-voltage circuit is unobstructed. When the output current of fuel cell stack 1 is 0, the fifth insulation resistance value of the vehicle's high-voltage circuit is collected. A start-up command is sent to the fuel cell system, and the system waits for it to start up completely. Once the output current of fuel cell stack 1 reaches A1, the sixth insulation resistance value of the vehicle's high-voltage circuit is collected again. Both the fifth and sixth insulation resistance values ​​are collected by the insulation resistance detection module 8.

[0048] The output current of the fuel cell stack 1 is controlled by the controller 9 adjusting the output voltage of the boost DC / DC21.

[0049] Based on the standard curve of insulation resistance versus air compressor speed, the fifth insulation resistance reference value when the output current of fuel cell stack 1 is 0 and the sixth insulation resistance reference value when the output current of fuel cell stack 1 is a1 are obtained. The difference between the fifth insulation resistance value and the fifth insulation resistance reference value is obtained to get dM5. The difference between the sixth insulation resistance value and the sixth insulation resistance reference value is obtained to get dM6.

[0050] If dM6 ≤ dM5, then the sealing performance of fuel cell stack 1 is normal. This is because as the fuel cell current increases, the pressure in the air, hydrogen, and coolant circuits increases. This increased pressure causes some compression within the fuel cell, but does not increase the internal leakage current or significantly reduce the insulation resistance. Furthermore, the increased current also increases the amount of water generated by the internal chemical reactions. However, this water generation does not significantly reduce the insulation resistance value. Therefore, the fuel cell stack sealing performance is considered normal.

[0051] If dM6 > dM5, then the sealing performance of fuel cell stack 1 is abnormal. This is because as the stack current increases, the pressure in the air, hydrogen, and coolant circuits increases. This increased pressure causes compression within the stack, significantly increasing internal leakage and drastically reducing insulation resistance. Furthermore, the increased stack current leads to increased water production from internal chemical reactions, which further reduces insulation resistance. Therefore, the fuel cell stack is judged to have an abnormal sealing performance.

[0052] like Figure 4The graph shows the insulation resistance curves for a vehicle fuel cell stack with normal sealing and those with abnormal sealing. The horizontal axis represents the stack current, and the vertical axis represents the insulation resistance value. As the stack current increases, the insulation resistance of a normally sealed stack decreases slightly, while the decrease is greater for an abnormally sealed stack. This is because as the stack current increases, the pressure in the air, hydrogen, and coolant circuits increases. When the stack sealing is slightly abnormal, the increased internal gas and liquid pressure causes some compression within the stack, increasing the leakage flow and thus reducing the insulation resistance. Furthermore, the increased stack current leads to increased water production from internal chemical reactions, which also lowers the insulation resistance value. dM represents the difference between the insulation resistance of an abnormally sealed stack and that of a normal stack. dM5 represents the insulation resistance difference when the water pump speed is 0, and dM6 represents the insulation resistance difference when the air compressor speed is n1. When dM5 increases, it may indicate a decrease in coolant conductivity. Therefore, the difference between dM6 and dM5 should be used as the evaluation object to avoid misjudgment due to changes in coolant conductivity.

[0053] Changes in current synchronously affect gas pressure, coolant pressure, and the amount of water generated in the reaction, enabling the identification of gas / liquid dual-loop leaks and the impact of electrochemical byproducts, providing the broadest detection dimensions.

[0054] Example 5 A computer-readable medium storing a computer program that, when executed, performs the following online detection method for fuel cell stack sealing based on adjusting the air compressor speed in Embodiment 2, or the online detection method for fuel cell stack sealing based on adjusting the water pump speed in Embodiment 3, or the online detection method for fuel cell stack sealing based on adjusting the fuel cell stack output current in Embodiment 4.

[0055] Example 6 A computer program product includes a computer program / instructions that, when executed by a processor, implement the online detection method for fuel cell stack sealing based on adjusting the air compressor speed in Embodiment 2, or the online detection method for fuel cell stack sealing based on adjusting the water pump speed in Embodiment 3, or the online detection method for fuel cell stack sealing based on adjusting the fuel cell stack output current in Embodiment 4.

[0056] The contents not described in detail in this specification are prior art known to those skilled in the art. Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0057] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0058] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0059] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A fuel cell, characterized in that, include: Fuel cell stack (1), air module (2), hydrogen module (3), voltage detector (4), boost DC / DC converter (5), distribution box (6), power battery (7), insulation resistance detection module (8), controller (9), cooling module (10); The fuel cell stack (1) is used to realize the chemical reaction between hydrogen and oxygen and output electrical energy; The air module (2) is used to drive air through an air compressor (22) to provide oxygen to the fuel cell stack (1); The hydrogen module (3) is used to supply hydrogen to the fuel cell stack (1); The voltage detector (4) is used to collect the voltage of each cell in the stack (1); The boost DC / DC (5) is used to boost and stabilize the electrical energy output by the fuel cell stack (1) and to collect the output current of the fuel cell stack. The distribution box (6) is used to distribute the boosted and stabilized electrical energy to various components of the vehicle; The power battery (7) is used to receive the electrical energy distributed by the distribution box (6) and to supply power to the various components of the vehicle as an auxiliary power source. The insulation resistance detection module (8) is used to collect the insulation resistance value of the high voltage circuit of the whole vehicle in real time; The cooling module (10) is used to drive the coolant to cool the fuel cell stack (1) via a water pump (101). The controller (9) is used to control the speed of the air compressor (22) of the air module (2), control the speed of the water pump (101) of the cooling module (10), and set the output voltage of the boost DC / DC (5) to control the output current of the fuel cell stack (1).

2. The fuel cell according to claim 1, characterized in that: The stack (1) is composed of multiple single cells connected in series; The air input terminal K1 of the air module (2) is connected to the air inlet terminal D1 of the fuel cell stack (1), and the air output terminal K2 of the air module (2) is connected to the air outlet terminal D2 of the fuel cell stack (1). The hydrogen input terminal H1 of the hydrogen module (3) is connected to the hydrogen inlet terminal D3 of the fuel cell stack (1), and the hydrogen output terminal H2 of the hydrogen module (3) is connected to the hydrogen outlet terminal D4 of the fuel cell stack (1). The positive and negative sampling terminals of the voltage detector (4) are respectively connected to the positive and negative terminals of the corresponding single cell of the stack (1); The low-voltage input terminal S1 of the boost DC / DC (5) is connected to the output bus terminal D5 of the stack (1); The input terminal P1 of the distribution box (6) is connected to the high voltage output terminal S2 of the boost DC / DC (5); The positive terminal L1 of the power battery (7) is connected to the positive busbar P2 of the distribution box (6), and the negative terminal L2 of the power battery (7) is connected to the negative busbar P3 of the distribution box (6). The negative detection terminal J1 of the insulation resistance detection module (8) is connected to the negative sampling terminal L3 of the power battery (7), the positive detection terminal J2 of the insulation resistance detection module (8) is connected to the positive sampling terminal L4 of the power battery (7), and the reference ground terminal J3 of the insulation resistance detection module (8) is connected to the vehicle frame. The coolant inlet Y1 of the cooling module (10) is connected to the coolant inlet D6 of the fuel cell stack (1), and the coolant outlet Y2 of the cooling module (10) is connected to the coolant outlet D7 of the fuel cell stack (1). The air compressor control terminal C1 of the controller (9) is connected to the controlled terminal K3 of the air compressor (22) of the air module (2), the water pump control terminal C2 of the controller (9) is connected to the controlled terminal Y3 of the water pump (101) of the cooling module (10), the DC / DC communication terminal C3 of the controller (9) is connected to the controlled terminal S3 of the boost DC / DC (5), and the voltage acquisition terminal C4 of the controller (9) is connected to the voltage communication terminal X1 of the voltage detector (4).

3. The method for online detection of fuel cell stack sealing performance based on adjusting air compressor speed according to claim 1 or 2, characterized in that, include: When the air compressor (22) of the air module (2) is at 0 speed, the first insulation resistance value of the high-voltage circuit of the whole vehicle is collected. The air compressor (22) speed of the air module (2) is set to k1, and the second insulation resistance value of the high-voltage circuit of the whole vehicle is collected again. Based on the standard curve of insulation resistance and air compressor speed, the first insulation resistance reference value when the air compressor (22) speed is 0 and the second insulation resistance reference value when the air compressor (22) speed is k1 are obtained. The difference between the first insulation resistance value and the first insulation resistance reference value is obtained to get dM1. The difference between the second insulation resistance value and the second insulation resistance reference value is obtained to get dM2. If dM2≤dM1, the sealing performance of the fuel cell stack (1) is normal; if dM2>dM1, the sealing performance of the fuel cell stack (1) is abnormal.

4. The method for online detection of fuel cell stack sealing performance based on adjusting air inlet pressure according to claim 3, characterized in that: The first insulation resistance value and the second insulation resistance value are both acquired by the insulation resistance detection module (8); The speed of the air compressor (22) of the air module (2) is adjusted by the controller (9).

5. The method for online detection of fuel cell stack sealing performance based on adjusting the speed of the water pump according to claim 1 or 2, characterized in that, include: When the water pump (101) of the cooling module (10) is at 0 speed, the third insulation resistance value of the high-voltage circuit of the whole vehicle is collected. The water pump (101) speed of the cooling module (10) is set to n1, and the fourth insulation resistance value of the high-voltage circuit of the whole vehicle is collected again. Based on the standard curve of insulation resistance and air compressor speed, the third insulation resistance value reference value when the speed of water pump (101) is 0 and the fourth insulation resistance value reference value when the speed of water pump (101) is n1 are obtained. The difference between the third insulation resistance value and the third insulation resistance value reference value is obtained to get dM3. The difference between the fourth insulation resistance value and the fourth insulation resistance value reference value is obtained to get dM4. If dM4≤dM3, the sealing performance of fuel cell stack (1) is normal; if dM4>dM3, the sealing performance of fuel cell stack (1) is abnormal.

6. The method for online detection of fuel cell stack sealing performance based on adjusting air inlet pressure according to claim 5, characterized in that: The third insulation resistance value and the fourth insulation resistance value are both collected by the insulation resistance detection module (8); The speed of the water pump (101) of the cooling module (10) is adjusted by the controller (9).

7. The method for online detection of fuel cell stack sealing performance based on adjusting the fuel cell stack output current according to claim 1 or 2, characterized in that, include: When the output current of the fuel cell stack (1) is 0, the fifth insulation resistance value of the high-voltage circuit of the whole vehicle is collected. When the output current of the fuel cell stack (1) is A1, the sixth insulation resistance value of the high-voltage circuit of the whole vehicle is collected again. According to the standard curve of insulation resistance and air compressor speed, the fifth insulation resistance value reference value when the output current of the fuel cell stack (1) is 0 and the sixth insulation resistance value reference value when the output current of the fuel cell stack (1) is a1 are obtained. The difference between the fifth insulation resistance value and the fifth insulation resistance value reference value is obtained to get dM5. The difference between the sixth insulation resistance value and the sixth insulation resistance value reference value is obtained to get dM6. If dM6≤dM5, the sealing performance of fuel cell stack (1) is normal; if dM6>dM5, the sealing performance of fuel cell stack (1) is abnormal.

8. The method for online detection of fuel cell stack sealing performance based on adjusting air inlet pressure according to claim 7, characterized in that: The fifth insulation resistance value and the sixth insulation resistance value are both collected by the insulation resistance detection module (8); The output current of the fuel cell stack (1) is controlled by the controller (9) adjusting the output voltage of the boost DC / DC21.

9. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is running, it executes the online detection method for fuel cell stack sealing based on adjusting the air compressor speed in claim 3, or the online detection method for fuel cell stack sealing based on adjusting the water pump speed in claim 5, or the online detection method for fuel cell stack sealing based on adjusting the fuel cell stack output current in claim 7.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the online detection method for fuel cell stack sealing based on adjusting the air compressor speed in claim 3, or the online detection method for fuel cell stack sealing based on adjusting the water pump speed in claim 5, or the online detection method for fuel cell stack sealing based on adjusting the fuel cell stack output current in claim 7.

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