A fuel cell insulation troubleshooting system, method, and vehicle

Abstract

The application relates to the technical field of fuel cells, in particular to a fuel cell insulation fault checking system, a method and a vehicle, the system comprising a stack package and a circulating water circuit and a deionization tank, the deionization tank being connected to the circulating water circuit; the circulating water circuit comprising high-pressure circulation and low-pressure circulation; the application can well solve the problem that a water pump cannot work and cannot clean the electric conductivity because a whole vehicle cannot be powered to high pressure due to insulation problems, the water pump is maintained at a certain rotating speed to clean the electric conductivity in a low-voltage power supply mode when the insulation problem occurs; manual water pump rotation to reduce the electric conductivity is avoided due to the high electric conductivity and the insulation problem, the maintenance cost is reduced; the application can effectively reduce the fault caused by the high electric conductivity and the insulation problem, improve the fuel cell reliability, and improve the user experience.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and specifically to a fuel cell insulation fault diagnosis system, method, and vehicle. Background Technology

[0002] Currently, fuel cell vehicles primarily employ a hybrid electric-electric approach, combining a fuel cell and a power battery to drive the vehicle. The power battery typically operates at a voltage platform of 500V (high voltage), thus requiring high insulation performance. The insulation resistance of existing fuel cells is limited by the coolant conductivity, resulting in lower insulation values ​​compared to the power battery. The fuel cell cooling system has extremely stringent requirements for liquid conductivity; excessively high coolant conductivity can cause low insulation failures in the fuel cell. To reliably prevent the hazards caused by low insulation, the vehicle performs real-time insulation detection upon startup, immediately cutting off power output when a low insulation value is detected.

[0003] The current startup logic for fuel cell vehicles is generally low-voltage electricity, high-voltage electricity, and closing the fuel cell contactor. After high-voltage electricity is applied, the insulation resistance is continuously monitored. If the insulation resistance is normal after high-voltage electricity is applied, but an insulation problem occurs when closing the fuel cell contactor, then it is confirmed that the insulation failure is caused by the fuel cell insulation. Currently, fuel cell insulation failures are generally caused by high conductivity. When a fuel cell vehicle is parked for an extended period, the cooling circulation system and deionizer are not working. Simultaneously, ions continuously precipitate into the deionized water from the water pump, PTC, intercooler, and radiator assembly, causing the conductivity to rise, potentially exceeding the conductivity threshold. This leads to an insulation failure in the fuel cell system. Because the insulation value cannot meet the requirements, the vehicle cannot be powered on, thus preventing filtration. Without filtration, the insulation value cannot be improved, again preventing power on, creating a vicious cycle that affects vehicle operation.

[0004] In the prior art, for example

[0005] Patent publication number CN113782792A describes a conductivity cleaning method for insulation faults caused by high conductivity. It detects insulation faults and performs conductivity cleaning when the fuel cell contactor is closed in the vehicle. However, this patent does not explain how the water pump works; it also does not address the assessment of the deion tank's lifespan; furthermore, the invention only determines the conditions for closing the fuel cell relay based on time. If the deion tank's lifespan has expired, it cannot activate the water pump to reduce conductivity. Prolonged operation would result in wasted energy and time, negatively impacting customer experience.

[0006] The patent publication number CN113745569A addresses high conductivity by periodically waking up the FCU after the vehicle has been parked for an extended period to detect conductivity and then using a battery-powered water pump for conductivity cleaning. This method involves periodic waking, which poses a safety hazard if personnel are performing maintenance at the time; it also consumes energy and is not energy efficient; and it can deplete the battery, affecting the vehicle's next start. Furthermore, there is no solution for situations where the conductivity remains high even after the deionization device has reached the end of its lifespan.

[0007] Patent publication number CN110943241A controls the operation of a water pump to perform conductivity cleaning by detecting the conductivity level. It also monitors the conductivity in the background and performs conductivity cleaning when the conductivity is too high. However, high conductivity does not necessarily cause insulation failure. Repeated cleaning will result in energy waste, and there is no monitoring of the lifespan of the deionization tank. Furthermore, this invention also determines whether to switch the water pump to clean conductivity based on the conductivity value, but it cannot achieve the purpose of reducing conductivity when the deionization tank reaches the end of its lifespan.

[0008] In summary, existing fuel cell vehicles perform insulation checks during high-voltage startup. When the insulation value is detected to be lower than a set value, the high-voltage power is cut off to protect personnel safety. The cooling medium of the fuel cell system is in contact with the bipolar plates inside the stack, making it conductive. It is essential to ensure the low conductivity of the fuel cell cooling medium to meet insulation requirements. Most insulation failures in vehicles are due to high conductivity of the fuel cell. During long-term static periods, conductivity precipitates from various components of the cooling system. Prolonged static periods lead to high conductivity and low insulation. When the vehicle is restarted to start the fuel cell, the low insulation prevents normal starting, causing the high-voltage power supply to the fuel cell to be cut off. This prevents the fuel cell's high-voltage water pump from operating, which in turn prevents conductivity reduction, thus preventing the vehicle from starting and creating a vicious cycle. Solving this problem requires on-site maintenance personnel to manually reconnect connectors and operate the water pump, increasing service costs and impacting customer usage. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a fuel cell insulation fault diagnosis system, method and vehicle that can accurately locate the source of insulation problems during the fuel cell self-test process, reduce the problem location time, improve service efficiency and enhance user experience.

[0010] To solve the above-mentioned technical problems, the first technical solution adopted by the present invention is as follows:

[0011] A fuel cell insulation fault diagnosis system includes a fuel cell stack, a circulating water circuit, and a deionization tank, wherein the deionization tank is connected to the circulating water circuit.

[0012] The circulating water circuit includes high-pressure circulation and low-pressure circulation.

[0013] To solve the above-mentioned technical problems, the second technical solution adopted by the present invention is as follows:

[0014] A method for troubleshooting insulation faults in fuel cells, including

[0015] When the vehicle is powered on, the fuel cell contactor is closed to determine whether the vehicle insulation value is greater than the preset value R. If so, the fuel cell is started using a high-voltage cycle. Otherwise, the fuel cell contactor is disconnected and the conductivity is detected. If the conductivity is greater than the preset value, the fuel cell is started using a low-voltage cycle.

[0016] When the low-pressure cycle operation time reaches T1, conductivity is tested. If it is lower than the preset value, the fuel cell contactor is closed to test the insulation value. If the insulation value meets the requirements, the high-pressure cycle is switched and the fuel cell is started. If the insulation value does not meet the requirements, other insulation faults in the fuel cell system are considered, and service personnel are notified to carry out maintenance.

[0017] To solve the above-mentioned technical problems, the third technical solution adopted by the present invention is as follows:

[0018] A vehicle includes a fuel cell contactor and the aforementioned fuel cell insulation fault diagnosis system.

[0019] The beneficial effects of this invention are as follows: By adding a low-voltage circulation mode, it effectively solves the problem that the water pump cannot work and clean conductivity because the vehicle cannot be powered by high voltage due to insulation issues. In the event of an insulation problem, a low-voltage power supply mode is used to maintain the water pump at a certain speed for conductivity cleaning; it avoids the need for manual pump operation at the after-sales site to reduce conductivity by terminating connectors due to high conductivity insulation problems, thus reducing maintenance costs; it can effectively reduce faults caused by high conductivity insulation problems, improve fuel cell reliability, and enhance user experience; it can effectively identify the lifespan of the deionizer, reducing the frequency of deionizer replacement; and by adding a start-up fault diagnosis function, it can quickly locate the low insulation fault point, reducing fault location time and saving labor costs. Attached Figure Description

[0020] Figure 1 This is a system block diagram of a fuel cell insulation fault diagnosis system according to a specific embodiment of the present invention;

[0021] Figure 2 This is a system block diagram of a fuel cell insulation fault diagnosis system according to a specific embodiment 2 of the present invention;

[0022] Figure 3 This is a flowchart of the troubleshooting method for the vehicle fuel cell insulation fault troubleshooting system according to a specific embodiment five of the present invention;

[0023] Labeling Explanation: 101, fuel cell stack; 102, fuel cell stack package; 103, high and low pressure circulating water pumps; 104, conductivity meter; 105, three-way valve; 106, heater; 107, high pressure circulating water pump; 108, low pressure circulating water pump; 201, filter; 202, water tank; 203, deionization tank; 204, heat dissipation assembly. Detailed Implementation

[0024] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0025] Please refer to Figures 1 to 3 A fuel cell insulation fault diagnosis system includes a fuel cell stack 102, a circulating water circuit, and a deionization tank 203, wherein the deionization tank 203 is connected to the circulating water circuit.

[0026] The circulating water circuit includes high-pressure circulation and low-pressure circulation.

[0027] Furthermore, the fuel cell stack 102 includes a fuel cell stack 101, which has a cooling water inlet and a cooling water outlet, and the circulating water path is connected to the cooling water inlet and the cooling water outlet.

[0028] Furthermore, the circulating water circuit includes a high-pressure circulating water pump 107, a low-pressure circulating water pump 108, a heat dissipation assembly 204, a heater 106, a three-way valve 105, and a water tank 202. The high-pressure circulating water pump 107 and the low-pressure circulating water pump 108 are connected in parallel to form a pump system; the heat dissipation assembly 204 and the heater 106 are connected in parallel to form a temperature control system; the cooling water outlet, the pump system, the temperature control system, the three-way valve 105, and the cooling water inlet are connected sequentially through pipelines.

[0029] The water tank 202 has an inlet and an outlet;

[0030] The inlets of the heat dissipation assembly 204, the deionization tank 203, and the water tank 202 are connected in sequence, and the pipe between the three-way valve 105 and the cooling water inlet is connected to the inlet of the water tank 202.

[0031] The outlet of the water tank 202 is connected to the cooling outlet and the pipeline between the pump system.

[0032] Furthermore, a filter 201 is provided between the heat dissipation assembly 204 and the three-way valve 105.

[0033] Furthermore, the high-pressure circulating water pump 107 and the low-pressure circulating water pump 108 are designed as a single high-low pressure circulating water pump 103.

[0034] Furthermore, a conductivity meter 104 is installed at the cooling water inlet.

[0035] A method for troubleshooting insulation faults in fuel cells, including

[0036] When the vehicle is powered on, the fuel cell contactor (or relay) is closed to determine whether the vehicle insulation value is greater than the preset value R. If so, the fuel cell is started using high-voltage cycling. Otherwise, the fuel cell contactor is disconnected and conductivity is detected. If the conductivity is greater than the preset value, the fuel cell is cycled at low voltage.

[0037] When the low-pressure cycle operation time reaches T1, conductivity is tested. If it is lower than the preset value, the fuel cell contactor is closed to test the insulation value. If the insulation value meets the requirements, the high-pressure cycle is switched and the fuel cell is started. If the insulation value does not meet the requirements, other insulation faults in the fuel cell system are considered, and service personnel are notified to carry out maintenance.

[0038] Furthermore, if the conductivity test still does not meet the requirements when the low-pressure cycle operation time reaches T1, the low-pressure cycle T2 continues to run. If the conductivity is lower than the preset value σ during this period, the subsequent process is executed. If the conductivity does not meet the requirements, it is considered a deionization failure, and the service personnel are notified to replace the deionization tank 203.

[0039] Furthermore, the insulation value of the entire vehicle is ≥100Ω / V.

[0040] A vehicle includes a fuel cell contactor and the aforementioned fuel cell insulation fault diagnosis system.

[0041] As described above, by adding a low-voltage circulation mode, the problem of the water pump failing to work and clean conductivity due to the vehicle's inability to apply high voltage caused by insulation issues can be effectively solved. In the event of an insulation problem, a low-voltage power supply mode is used to maintain the water pump at a certain speed for conductivity cleaning. This avoids the need for manual pump operation at the after-sales site to reduce conductivity by terminating connectors, thus reducing maintenance costs. It can effectively reduce faults caused by high conductivity insulation problems, improve fuel cell reliability, and enhance user experience. It can also effectively identify the lifespan of the deionizer 203, reducing the frequency of deionizer 203 replacement. Furthermore, by adding a start-up fault diagnosis function, it can quickly locate the insulation low fault point, reducing fault location time and saving labor costs.

[0042] The low-pressure circulation refers to the low-speed flow of the circulating water, i.e., the low-speed rotation of the water pump; the high-pressure circulation refers to the high-speed flow of the circulating water, i.e., the high-speed rotation of the water pump; the above high and low are the results of comparison between them in this application.

[0043] Example 1

[0044] A fuel cell insulation fault diagnosis system includes a fuel cell stack, a circulating water circuit, and a deionization tank, wherein the deionization tank is connected to the circulating water circuit.

[0045] The circulating water circuit includes high-pressure circulation and low-pressure circulation.

[0046] The fuel cell stack includes a fuel cell stack, which has a cooling water inlet and a cooling water outlet, and the circulating water path is connected to the cooling water inlet and the cooling water outlet.

[0047] The circulating water circuit includes a high-pressure circulating water pump, a low-pressure circulating water pump, a heat dissipation assembly, a heater, a three-way valve, and a water tank. The high-pressure circulating water pump and the low-pressure circulating water pump are connected in parallel to form a pump system; the heat dissipation assembly and the heater are connected in parallel to form a temperature control system; the cooling water outlet, the pump system, the temperature control system, the three-way valve, and the cooling water inlet are connected in sequence through pipelines.

[0048] The water tank has an inlet and an outlet;

[0049] The inlets of the heat dissipation assembly, deionizer, and water tank are connected in sequence, and the pipe between the three-way valve and the cooling water inlet is connected to the inlet of the water tank.

[0050] The outlet of the water tank is connected to the cooling outlet and the pipeline between the pump system.

[0051] A filter is installed between the heat dissipation assembly and the three-way valve.

[0052] A conductivity meter is installed at the cooling water inlet.

[0053] Example 2

[0054] A fuel cell insulation fault diagnosis system, which is the same as that in Embodiment 1, will not be repeated here. The high-pressure circulating water pump and the low-pressure circulating water pump are designed as an integrated high and low pressure circulating water pump.

[0055] Example 3

[0056] A troubleshooting method for a fuel cell insulation fault detection system based on Embodiment 1 or Embodiment 2, comprising:

[0057] When the vehicle is powered on, the fuel cell contactor (or relay) is closed to determine whether the vehicle insulation value is greater than the preset value R. If so, the fuel cell is started using high-voltage cycling. Otherwise, the fuel cell contactor is disconnected and conductivity is detected. If the conductivity is greater than the preset value, the fuel cell is cycled at low voltage.

[0058] When the low-pressure cycle operation time reaches T1, conductivity is tested. If it is lower than the preset value, the fuel cell contactor is closed to test the insulation value. If the insulation value meets the requirements, the high-pressure cycle is switched and the fuel cell is started. If the insulation value does not meet the requirements, other insulation faults in the fuel cell system are considered, and service personnel are notified to carry out maintenance.

[0059] If the conductivity test still does not meet the requirements when the low-pressure cycle operation time reaches T1, the low-pressure cycle T2 will continue. If the conductivity is lower than the preset value σ during this period, the subsequent process will be executed. If the conductivity does not meet the requirements, the deionization is considered to be faulty, and the service personnel will be notified to replace the deionization tank.

[0060] The insulation value of the entire vehicle is ≥100Ω / V.

[0061] Example 4

[0062] A vehicle, characterized in that it includes a fuel cell contactor and a fuel cell insulation fault detection system as described in Embodiment 1 or Embodiment 2.

[0063] Example 5

[0064] A troubleshooting method for a vehicle fuel cell insulation fault detection system, including:

[0065] The vehicle is powered on in pure electric mode;

[0066] When the vehicle is powered on, the fuel cell contactor (or relay) is closed to determine whether the vehicle insulation value is greater than the preset value R. If so, the fuel cell is started using a high-voltage cycle. Otherwise, the fuel cell contactor is disconnected and the conductivity is tested. If the conductivity is greater than the preset value, the fuel cell is cycled at low voltage. Otherwise, other insulation faults in the fuel cell system are considered, and service personnel are notified to carry out repairs.

[0067] When the low-pressure cycle operation time reaches T1, conductivity is tested. If it is lower than the preset value σ, the fuel cell contactor is closed to test the insulation value. If the insulation value meets the requirements, the high-pressure cycle is switched and the fuel cell is started. If the insulation value does not meet the requirements, other insulation faults in the fuel cell system are considered, and service personnel are notified to carry out maintenance.

[0068] If the conductivity test still does not meet the requirements when the low-pressure cycle operation time reaches T1, the low-pressure cycle T2 will continue. If the conductivity is lower than the preset value σ during this period, the subsequent process will be executed. If the conductivity is not lower than the preset value σ, the deionization failure will be considered and the service personnel will be notified to replace the deionization tank.

[0069] The insulation value of the entire vehicle is ≥100Ω / V.

[0070] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A fuel cell insulation troubleshooting system, characterized by, The stack package and the circulating water circuit and the deionization tank are connected in series. The circulating water circuit comprises a high-pressure circulating water circuit and a low-pressure circulating water circuit. The stack package comprises a stack, and the stack is provided with a cooling water inlet and a cooling water outlet, and the circulating water circuit is connected to the cooling water inlet and the cooling water outlet. The circulating water circuit comprises a high-pressure circulating water pump, a low-pressure circulating water pump, a heat dissipation assembly, a heater, a three-way valve and a water tank, the high-pressure circulating water pump and the low-pressure circulating water pump are connected in parallel to form a pump system, the heat dissipation assembly and the heater are connected in parallel to form a temperature regulating system, and the cooling water outlet, the pump system, the temperature regulating system, the three-way valve and the cooling water inlet are sequentially connected through pipes. The water tank is provided with an inlet and an outlet. The heat dissipation assembly, the deionization tank and the inlet of the water tank are sequentially connected, and the pipe between the three-way valve and the cooling water inlet is communicated with the inlet of the water tank. The outlet of the water tank is communicated with the pipe between the cooling water outlet and the pump system.

2. The fuel cell insulation fault isolation system of claim 1, wherein, A filter is arranged between the heat dissipation assembly and the three-way valve.

3. The fuel cell insulation fault isolation system of claim 1, wherein, The high-pressure circulating water pump and the low-pressure circulating water pump are designed in an integrated manner as a high-low pressure circulating water pump.

4. The fuel cell insulation fault isolation system of claim 1, wherein, An electric conductivity meter is arranged at the cooling water inlet.

5. A method of isolating a fault in a fuel cell, characterized by, The system comprises The fuel cell contactor is closed when the vehicle is started, and it is determined whether the insulation value of the vehicle is greater than a preset value, if yes, the fuel cell is started by high-pressure circulation, if not, the fuel cell contactor is disconnected and electric conductivity detection is performed, if the electric conductivity is greater than a preset value, the fuel cell is started by low-pressure circulation; When the low-pressure circulation running time reaches T1, electric conductivity detection is performed, if the electric conductivity is lower than a preset value, the fuel cell contactor is closed for insulation value detection, when the insulation value meets the requirements, the fuel cell is started by high-pressure circulation; if the insulation value does not meet the requirements, it is considered that other insulation faults of the fuel cell system occur, and service personnel are informed to repair; If the electric conductivity detection is still not satisfied when the low-pressure circulation running time reaches T1, the low-pressure circulation is continued to run for T2, during which, if the electric conductivity is lower than a preset value, subsequent processes are performed, if the electric conductivity does not meet the requirements, it is considered that a deionization fault occurs, and service personnel are informed to replace the deionization tank. The insulation value of the vehicle is greater than or equal to 100Ω / V.

6. A vehicle characterized by comprising: The system comprises a fuel cell contactor and the fuel cell insulation fault diagnosis system according to any one of claims 1-4.

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