A method for calculating fuel cell operating status

Abstract

The present invention relates to a method for calculating the operating state of a fuel cell. The calculation method sets a target operating state reference group, and uses a fuel cell stack inspection to collect the voltage of a single cell of the fuel cell stack when the fuel cell system is actually operating under the conditions of high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio. The corresponding result is obtained through calculation. When the fuel cell system is actually operating, the fuel cell stack inspection is used to collect the voltage of the single cell of the fuel cell stack, and the ΔVTR under different conditions is compared through calculation, wherein the largest value indicates that there is a problem with the operating condition corresponding to the value, and then the two corresponding ΔVTRs under the operating condition are compared, and the smaller ΔVTR value indicates that the corresponding condition is the problem point; and the operating condition of the fuel cell stack is adjusted according to the calculation result to return the fuel cell stack to a healthy operating state.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a method for calculating the operating state of a fuel cell. Background Art

[0002] During the operation of the fuel cell system, when the system environment, operating conditions, system status, etc. change, the state of the fuel cell will change, causing the fuel cell to be in an unhealthy operating state. Long-term operation in an unhealthy state will cause the fuel cell performance to continue to decay, which will in turn damage the fuel cell system and affect the service life of the fuel cell. Therefore, real-time monitoring of the operating status of the fuel cell system and timely adjustment of operating conditions to ensure that the fuel cell system is in a healthy operating state are of far-reaching significance for improving the reliability and durability of the fuel cell system.

[0003] During the operation of an existing fuel cell system, it is usually necessary to deploy multiple sensors to monitor the operating status of the fuel cell system to ensure the stability of the operation of the fuel cell system. The above method not only increases the assembly complexity of the fuel cell due to the excessive number of sensors during installation, but also increases the operating cost of the fuel cell system.

[0004] The health status of a fuel cell is mainly reflected in its cell voltage. Adverse operating conditions such as over-dryness, over-humidity, lack of air, and mechanical damage can change the cell voltage of the fuel cell. Therefore, if you want to diagnose the status of the fuel cell or rely on the cell voltage to control the fuel cell system, you need to know the cell voltage of the fuel cell and use the fuel cell and inspection in conjunction. The fuel cell stack inspection (CVM) collects the fuel cell cell voltage (or total stack voltage) signal and sends it to the fuel cell system controller. By checking the cell voltage signal, it determines the working status of the fuel cell and performs corresponding control operations.

[0005] Therefore, it is urgent to design a method for calculating the operating status of a fuel cell to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0006] To achieve the above object, the present invention provides a method for calculating the operating state of a fuel cell, and the present invention adopts the following technical solutions:

[0007] A method for calculating the operating state of a fuel cell, the method comprising the following steps:

[0008] S1. Use the fuel cell stack inspection to collect the voltage of the fuel cell stack cells, and record the voltage of the cells as V n, where n is the inspection number of the fuel cell stack, the value range of n is {1, 2, 3, ..., m}, where m is the number of single cells in the fuel cell stack, and the voltage difference ΔV between the single cells before and after the fuel cell stack k It is expressed as:

[0009] ΔV k =V n+1 -V n (1);

[0010] Where k = n, and the value range of n is {1, 2, 3, ..., (m-1)}, ΔV k Normalization processing is performed to obtain the voltage trend series VT k ;

[0011] S2. Use the fuel cell stack inspection method described in step S1 to calculate the voltage trend series VT of the fuel cell stack when it is running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio. k ;

[0012] S3. Set the target operating state reference group, use the fuel cell stack inspection, and calculate the voltage trend series VT of the fuel cell stack when it is running under the target operating conditions according to the method described in step S1. k _ref; voltage trend series VT when running under target operating conditions k _ref is respectively related to the voltage trend series VT when running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio k Make a difference and get the reference voltage trend series difference ΔVT k _ref;

[0013] S4. When the fuel cell system is actually running, use the fuel cell stack inspection to calculate the voltage trend series VT of the fuel cell stack under the current conditions in real time according to the method described in step S1. k _now; Make the voltage trend series VT under current conditions k _now and the voltage trend series VT when running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio k Make a difference and get the current voltage trend series difference ΔVT k _now;

[0014] S5. The difference ΔVT of the multiple reference voltage trend series obtained in step S3 k _ref are normalized respectively, and the resulting series is recorded as the comparison reference voltage trend series VTT k _ref, the specific processing method is as follows:

[0015]

[0016] Then, the reference voltage trend series VTT is compared k _ref is calculated as follows, and the result is recorded as the reference voltage trend rate VTR_ref. The specific formula is as follows:

[0017]

[0018] S6. The difference ΔVT of the multiple current voltage trend series obtained in step S4 k _now are normalized respectively, and the result series is recorded as the comparison current voltage trend series VTT k _now, the specific processing method is as follows:

[0019]

[0020] Then, the current voltage trend series VTT will be compared k _now is calculated as follows, and the result is recorded as the current voltage trend rate VTR_now. The specific formula is as follows:

[0021]

[0022] S7. respectively subtract the current voltage trend rate VTR_now corresponding to the high coolant temperature, the low coolant temperature, the high cathode humidity, the low cathode humidity, the high anode back pressure, the low anode back pressure, the high cathode stoichiometric ratio, the low cathode stoichiometric ratio, the high anode stoichiometric ratio, and the low anode stoichiometric ratio from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR;

[0023] S8. Subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_temp; subtract the ΔVTR corresponding to the high cathode humidity from the ΔVTR corresponding to the low cathode humidity, and take the absolute value as ΔVTR_HR; subtract the ΔVTR corresponding to the high anode back pressure from the ΔVTR corresponding to the low anode back pressure, and take the absolute value as ΔVTR_press; subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_CaSR; subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_AnSR;

[0024] S9. Compare ΔVTR_temp, ΔVTR_HR, ΔVTR_press, ΔVTR_CaSR and ΔVTR_AnSR, where the largest value indicates that there is a problem with the operating condition corresponding to the value, and then compare the two corresponding ΔVTRs under the operating condition. The smaller ΔVTR value indicates that the corresponding condition is the problem point; and adjust the fuel cell stack operating conditions according to the calculation results to return the fuel cell stack to a healthy operating state.

[0025] Furthermore, in step S1, ΔV k Normalization processing is performed to obtain the voltage trend series VT k , the specific processing methods are as follows:

[0026]

[0027] Furthermore, in step S2, the voltage trend series under the high coolant temperature operating condition is recorded as VT k _temp_max, the voltage trend series under low coolant temperature operating conditions is recorded as VT k _temp_min, the voltage trend series under high cathode humidity operating conditions is recorded as VT k The voltage trend series under the operating conditions of _HR_max and low cathode humidity is recorded as VT k The voltage trend series under the conditions of _HR_min and high anode back pressure is recorded as VT k _press_max, the voltage trend series under low anode back pressure operating conditions is recorded as VT k _press_min, the voltage trend series under the operating conditions of high cathode stoichiometric ratio is recorded as VT k The voltage trend series under the conditions of _CaSR_max and low cathode stoichiometric ratio operation is recorded as VT k The voltage trend series under the conditions of _CaSR_min and high anode stoichiometric ratio is recorded as VT k _AnSR_max, the voltage trend series under low anode stoichiometric ratio operating conditions is recorded as VT k _AnSR_min.

[0028] Furthermore, the specific calculation of step S3 is as follows:

[0029]

[0030] Furthermore, the specific calculation of step S4 is as follows:

[0031]

[0032] Furthermore, the step S7 is specifically as follows:

[0033] The current voltage trend rate VTR_now corresponding to high coolant temperature is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_temp_max; the current voltage trend rate VTR_now corresponding to low coolant temperature is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_temp_min; the current voltage trend rate VTR_now corresponding to high cathode humidity is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_HR_max; the current voltage trend rate VTR_now corresponding to low cathode humidity is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_HR_min; the current voltage trend rate VTR_now corresponding to high anode back pressure is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_max; the current voltage trend rate VTR_now corresponding to low anode back pressure is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_max; The corresponding current voltage trend rate VTR_now is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_min; the current voltage trend rate VTR_now corresponding to the high cathode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_CaSR_max; the current voltage trend rate VTR_now corresponding to the low cathode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_CaSR_min; the current voltage trend rate VTR_now corresponding to the high anode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_AnSR_max; the current voltage trend rate VTR_now corresponding to the low anode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_AnSR_min; the specific calculation is as follows:

[0034]

[0035] Furthermore, the specific calculation of step S8 is as follows:

[0036]

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] By designing a fuel cell operating state calculation method, a target operating state reference group is set, and the fuel cell stack inspection is used to collect the fuel cell stack single cell voltage when operating under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio conditions, and the corresponding results are obtained after calculation. When the fuel cell system is actually operating, the fuel cell stack inspection is used to collect the fuel cell stack single cell voltage, and the ΔVTR under different conditions is compared after calculation, wherein the largest value indicates that there is a problem with the operating condition corresponding to the value, and then the two corresponding ΔVTRs under the operating condition are compared, and the smaller ΔVTR value indicates that the corresponding condition is the problem point; and the fuel cell stack operating conditions are adjusted according to the calculation results to return the fuel cell stack to a healthy operating state.

[0039] The above calculation method can find the problem points of the current operating conditions of the fuel cell system only by calculating the voltage collected during the stack inspection, thereby monitoring the operating status of the stack and ensuring the safety of the stack operation. Compared with the traditional method, it reduces the setting and installation of sensors, effectively reducing product costs and installation complexity.

[0040] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A ΔVTR calculation diagram for low coolant temperature verification according to an embodiment of the present invention is shown;

[0043] Figure 2 A ΔVTR calculation diagram for high coolant temperature verification according to an embodiment of the present invention is shown;

[0044] Figure 3 A ΔVTR calculation diagram for low cathode humidity verification according to an embodiment of the present invention is shown;

[0045] Figure 4 A ΔVTR calculation diagram for verifying a low cathode stoichiometric ratio according to an embodiment of the present invention is shown;

[0046] Figure 5A ΔVTR calculation diagram for verifying a low anode stoichiometric ratio according to an embodiment of the present invention is shown;

[0047] Figure 6 A ΔVTR calculation diagram for low anode back pressure verification according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] An embodiment of the present invention provides a method for calculating a fuel cell operating state, the method comprising:

[0050] S1. Use the fuel cell stack inspection to collect the voltage of the fuel cell stack cells, and record the voltage of the cells as V n , where n is the inspection number of the fuel cell stack, the value range of n is {1, 2, 3, ..., m}, where m is the number of single cells in the fuel cell stack, and the voltage difference ΔV between the single cells before and after the fuel cell stack k It is expressed as:

[0051] ΔV k =V n+1 -V n (1);

[0052] Where k = n, and the value range of n is {1, 2, 3, ..., (m-1)}, ΔV k Normalization processing is performed to obtain the voltage trend series VT k , the specific processing methods are as follows:

[0053]

[0054] S2. Use the fuel cell stack inspection method described in step S1 to calculate the voltage trend series VT of the fuel cell stack when it is running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio. k , the voltage trend series under high coolant temperature operating conditions is recorded as VT k _temp_max, the voltage trend series under low coolant temperature operating conditions is recorded as VT k_temp_min, the voltage trend series under high cathode humidity operating conditions is recorded as VT k The voltage trend series under the operating conditions of _HR_max and low cathode humidity is recorded as VT k The voltage trend series under the conditions of _HR_min and high anode back pressure is recorded as VT k _press_max, the voltage trend series under low anode back pressure operating conditions is recorded as VT k _press_min, the voltage trend series under the operating conditions of high cathode stoichiometric ratio is recorded as VT k The voltage trend series under the conditions of _CaSR_max and low cathode stoichiometric ratio operation is recorded as VT k The voltage trend series under the conditions of _CaSR_min and high anode stoichiometric ratio is recorded as VT k _AnSR_max, the voltage trend series under low anode stoichiometric ratio operating conditions is recorded as VT k _AnSR_min;

[0055] S3. Set the target operating state reference group, use the fuel cell stack inspection, and calculate the voltage trend series VT of the fuel cell stack when it is running under the target operating conditions according to the method described in step S1. k _ref; voltage trend series VT when running under target operating conditions k _ref is respectively related to the voltage trend series VT when running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio k Make a difference and get the reference voltage trend series difference ΔVT k _ref, the specific calculation is as follows:

[0056]

[0057] ΔVT k _ref_HR_min=VT k _ref-VT k _HR_min

[0058] ΔVT k _ref_press_max=VT k _ref-VT k _press_max

[0059] ΔVT k _ref_press_min=VT k _ref-VT k _press_min (3);

[0060] ΔVT k _ref_CaSR_max=VT k _ref-VT k _CaSR_max

[0061] ΔVT k _ref_CaSR_min=VT k _ref-VT k _CaSR_min

[0062] ΔVT k _ref_AnSR_max=VT k _ref-VT k _AnSR_max

[0063] ΔVT k _ref_AnSR_min=VT k _ref-VT k _AnSR_min

[0064] S4. When the fuel cell system is actually running, use the fuel cell stack inspection to calculate the voltage trend series VT of the fuel cell stack under the current conditions in real time according to the method described in step S1. k _now; Make the voltage trend series VT under current conditions k _now and the voltage trend series VT when running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio k Make a difference and get the current voltage trend series difference ΔVT k _now, the specific calculation is as follows:

[0065]

[0066] S5. The difference ΔVT of the multiple reference voltage trend series obtained in step S3 k _ref are normalized respectively, and the resulting series is recorded as the comparison reference voltage trend series VTT k _ref, the specific processing method is as follows:

[0067]

[0068] Then, the reference voltage trend series VTT is compared k _ref is calculated as follows, and the result is recorded as the reference voltage trend rate VTR_ref. The specific formula is as follows:

[0069]

[0070] S6. The difference ΔVT of the multiple current voltage trend series obtained in step S4 k _now are normalized respectively, and the result series is recorded as the comparison current voltage trend series VTT k _now, the specific processing method is as follows:

[0071]

[0072] Then, the current voltage trend series VTT will be compared k _now is calculated as follows, and the result is recorded as the current voltage trend rate VTR_now. The specific formula is as follows:

[0073]

[0074] S7. Subtract the current voltage trend rate VTR_now corresponding to the high coolant temperature, the low coolant temperature, the high cathode humidity, the low cathode humidity, the high anode back pressure, the low anode back pressure, the high cathode stoichiometric ratio, the low cathode stoichiometric ratio, the high anode stoichiometric ratio, and the low anode stoichiometric ratio from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR, which is as follows:

[0075] The current voltage trend rate VTR_now corresponding to high coolant temperature is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_temp_max; the current voltage trend rate VTR_now corresponding to low coolant temperature is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_temp_min; the current voltage trend rate VTR_now corresponding to high cathode humidity is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_HR_max; the current voltage trend rate VTR_now corresponding to low cathode humidity is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_HR_min; the current voltage trend rate VTR_now corresponding to high anode back pressure is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_max; the current voltage trend rate VTR_now corresponding to low anode back pressure is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_max; The corresponding current voltage trend rate VTR_now is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_min; the current voltage trend rate VTR_now corresponding to the high cathode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_CaSR_max; the current voltage trend rate VTR_now corresponding to the low cathode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_CaSR_min; the current voltage trend rate VTR_now corresponding to the high anode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_AnSR_max; the current voltage trend rate VTR_now corresponding to the low anode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_AnSR_min; the specific calculation is as follows:

[0076]

[0077] S8. Subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_temp; subtract the ΔVTR corresponding to the high cathode humidity from the ΔVTR corresponding to the low cathode humidity, and take the absolute value as ΔVTR_HR; subtract the ΔVTR corresponding to the high anode back pressure from the ΔVTR corresponding to the low anode back pressure, and take the absolute value as ΔVTR_press; subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_CaSR; subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_AnSR; the specific calculation is as follows:

[0078]

[0079] S9. Compare ΔVTR_temp, ΔVTR_HR, ΔVTR_press, ΔVTR_CaSR and ΔVTR_AnSR, where the largest value indicates that there is a problem with the operating condition corresponding to the value, and then compare the two corresponding ΔVTRs under the operating condition. The smaller ΔVTR value indicates that the corresponding condition is the problem point; and adjust the fuel cell stack operating conditions according to the calculation results to return the fuel cell stack to a healthy operating state.

[0080] Specifically, if ΔVTR_temp, it means that the temperature of the battery stack is too high or too low in the current operating state, and then compare ΔVTR_temp_max and ΔVTR_temp_min. If ΔVTR_temp_max is smaller, it means that the operating temperature of the battery stack is too high at this time; if ΔVTR_temp_min is smaller, it means that the operating temperature of the battery stack is too low at this time. If the operating temperature of the battery stack is too high, the cooling water temperature is reduced by increasing the speed of the cooling fan to ensure that the battery stack operates at a suitable temperature; if the operating temperature of the battery stack is too low, the cooling water temperature is increased by reducing the speed of the cooling fan to ensure that the battery stack operates at a suitable temperature.

[0081] Adjusting the fuel cell stack operating conditions based on the calculation results may also include: if the cathode stoichiometric ratio is too low, increasing the air compressor speed to increase the cathode air supply, thereby ensuring that the stack has a suitable air stoichiometric ratio during operation; if the cathode humidity is too low, checking whether the fuel cell system humidifier is faulty or ineffective, and considering replacing the humidifier or performing repairs.

[0082] The present invention provides a specific embodiment to experimentally verify the above scheme, set a target operating state reference group, with a coolant temperature of 65°C, a cathode humidity of 60%, a cathode stoichiometric ratio of 2.2, an anode stoichiometric ratio of 1.8, and an anode back pressure of 140kPa, use a fuel cell stack inspection, and calculate the voltage trend series VT of the fuel cell stack when it is running under the target operating conditions according to the method described in step S1. k _ref.

[0083] The coolant temperature is adjusted to 50°C, the cathode humidity stoichiometric ratio is 1.6, the anode stoichiometric ratio is 1.4, the anode back pressure is 100 kPa, and the cathode humidity is 0%. The fuel cell stack is inspected and the voltage trend series VT of the fuel cell stack when it is running under the conditions of low coolant temperature, low cathode humidity, low anode back pressure, low cathode stoichiometric ratio, and low anode stoichiometric ratio is calculated according to the method described in step S1. k The results are VT k _temp_min, VT k _HR_min, VT k _press_min, VT k _CaSR_min, VTk _AnSR_min.

[0084] The coolant temperature is adjusted to 80°C, the cathode humidity stoichiometric ratio is 2.6, the anode stoichiometric ratio is 2.4, the anode back pressure is 170 kPa, and the cathode humidity is 100%. The fuel cell stack is inspected and the voltage trend series VT of the fuel cell stack when it is running under the conditions of high coolant temperature, high cathode humidity, high anode back pressure, high cathode stoichiometric ratio, and high anode stoichiometric ratio is calculated according to the method described in step S1. k The results are VT k _temp_max, VT k _HR_max, VT k _press_max, VT k _CaSR_max, VT k _AnSR_max.

[0085] The calculation results are verified by experimental verification. Figure 1-6 As shown:

[0086] like Figure 1 The following is the coolant low temperature verification result, which is Figure 1 It can be seen that the ΔVTR_temp value is the largest, which means that the temperature of the battery stack is abnormal at this time. Among them, ΔVTR_temp_min is less than ΔVTR_temp_max, which means that the temperature abnormality at this time is caused by the coolant temperature being too low. In this experiment, the operating temperature is 55°C, and the reference coolant temperature is 65°C, which means that the calculation result is accurate.

[0087] like Figure 2 The following is the coolant high temperature verification result, which is Figure 2 It can be seen that the ΔVTR_temp value is the largest, which means that the temperature of the battery stack is abnormal at this time. Among them, ΔVTR_temp_max is less than ΔVTR_temp_min, which means that the temperature abnormality at this time is caused by the excessively high coolant temperature. In this experiment, the operating temperature is 75°C, and the reference coolant temperature is 65°C, which means that the calculation result is accurate.

[0088] like Figure 3 The figure shows the verification result of low cathode humidity. Figure 3 It can be seen that the ΔVTR_HR value is the largest, which means that the cathode humidity of the battery stack is abnormal at this time, where ΔVTR_HR_min is less than ΔVTR_HR_max, which means that the cathode humidity abnormality at this time is caused by the cathode humidity being too low. In this experiment, the operating cathode humidity is 20%, and the reference cathode humidity is 60%, which means that the calculation result is accurate.

[0089] like Figure 4 The figure shows the verification result of the cathode stoichiometric ratio being too low. Figure 4 It can be seen that the ΔVTR_CaSR value is the largest, which means that the cathode stoichiometric ratio of the fuel cell stack is abnormal at this time, where ΔVTR_CaSR_min is less than ΔVTR_CaSR_max, which means that the abnormal cathode stoichiometric ratio at this time is caused by the cathode stoichiometric ratio being too low. In this experiment, the operating cathode stoichiometric ratio is 1.8, and the reference cathode stoichiometric ratio is 2.2, which means that the calculated result is accurate.

[0090] like Figure 5 The figure shows the verification result of the anode stoichiometric ratio being too low. Figure 5 It can be seen that the ΔVTR_AnSR value is the largest, which means that the anode stoichiometric ratio of the fuel cell stack is abnormal at this time, where ΔVTR_AnSR_min is less than ΔVTR_AnSR_max, which means that the anode stoichiometric ratio abnormality at this time is caused by the anode stoichiometric ratio being too low. In this experiment, the operating anode stoichiometric ratio is 1.6, and the reference anode stoichiometric ratio is 1.8, which means that the calculation result is accurate.

[0091] like Figure 6 The figure shows the verification result of the anode back pressure being too low. Figure 6 It can be seen that the ΔVTR_press value is the largest, which means that the anode back pressure of the fuel cell stack is abnormal at this time, where ΔVTR_press_min is less than ΔVTR_press_max, which means that the anode back pressure abnormality at this time is caused by the anode back pressure being too low. In this experiment, the operating anode back pressure is 120 kPa, and the reference anode back pressure is 140 kPa, which means that the calculation result is accurate.

[0092] By designing a fuel cell operating state calculation method, a target operating state reference group is set, and the fuel cell stack inspection is used to collect the fuel cell stack single cell voltage when operating under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio conditions, and the corresponding results are obtained after calculation. When the fuel cell system is actually operating, the fuel cell stack inspection is used to collect the fuel cell stack single cell voltage, and the ΔVTR under different conditions is compared after calculation, wherein the largest value indicates that there is a problem with the operating condition corresponding to the value, and then the two corresponding ΔVTRs under the operating condition are compared, and the smaller ΔVTR value indicates that the corresponding condition is the problem point; and the fuel cell stack operating conditions are adjusted according to the calculation results to return the fuel cell stack to a healthy operating state.

[0093] The above calculation method can find the problem points of the current operating conditions of the fuel cell system only by calculating the voltage collected during the stack inspection, thereby monitoring the operating status of the stack and ensuring the safety of the stack operation. Compared with the traditional method, it reduces the setting and installation of sensors, effectively reducing product costs and installation complexity.

[0094] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the operating state of a fuel cell, characterized in that: The calculation method comprises the following steps: S1. Use the fuel cell stack inspection to collect the voltage of the fuel cell stack cells, and record the voltage of the cells as V n , where n is the inspection number of the fuel cell stack, the value range of n is {1, 2, 3, ..., m}, where m is the number of single cells in the fuel cell stack, and the voltage difference ΔV between the single cells before and after the fuel cell stack k It is expressed as: ΔV k =V n+1 -V n (1); Where k = n, and the value range of n is {1, 2, 3, ..., (m-1)}, ΔV k Normalization processing is performed to obtain the voltage trend series VT k ; The specific processing methods are as follows: S2. Use the fuel cell stack inspection method described in step S1 to calculate the voltage trend series VT of the fuel cell stack when it is running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio. k ; S3. Set the target operating state reference group, use the fuel cell stack inspection, and calculate the voltage trend series VT of the fuel cell stack when it is running under the target operating conditions according to the method described in step S1. k _ref; voltage trend series VT when running under target operating conditions k _ref is respectively related to the voltage trend series VT when running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio k Make a difference and get the reference voltage trend series difference ΔVT k _ref; S4. When the fuel cell system is actually running, use the fuel cell stack inspection to calculate the voltage trend series VT of the fuel cell stack under the current conditions in real time according to the method described in step S1. k _now; Make the voltage trend series VT under current conditions k _now and the voltage trend series VT when running under high coolant temperature, low coolant temperature, high cathode humidity, low cathode humidity, high anode back pressure, low anode back pressure, high cathode stoichiometric ratio, low cathode stoichiometric ratio, high anode stoichiometric ratio, and low anode stoichiometric ratio respectively k Make a difference and get the current voltage trend series difference ΔVT k _now; S5. The difference ΔVT of the multiple reference voltage trend series obtained in step S3 k _ref are normalized respectively, and the resulting series is recorded as the comparison reference voltage trend series VTT k _ref, the specific processing method is as follows: Then, the reference voltage trend series VTT is compared k _ref is calculated as follows, and the result is recorded as the reference voltage trend rate VTR_ref. The specific formula is as follows: S6. The difference ΔVT of the multiple current voltage trend series obtained in step S4 k _now are normalized respectively, and the result series is recorded as the comparison current voltage trend series VTT k _now, the specific processing method is as follows: Then, the current voltage trend series VTT will be compared k _now is calculated as follows, and the result is recorded as the current voltage trend rate VTR_now. The specific formula is as follows: S7. respectively subtract the current voltage trend rate VTR_now corresponding to the high coolant temperature, the low coolant temperature, the high cathode humidity, the low cathode humidity, the high anode back pressure, the low anode back pressure, the high cathode stoichiometric ratio, the low cathode stoichiometric ratio, the high anode stoichiometric ratio, and the low anode stoichiometric ratio from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR; S8. Subtract the ΔVTR corresponding to the high coolant temperature from the ΔVTR corresponding to the low coolant temperature, and take the absolute value as ΔVTR_temp; subtract the ΔVTR corresponding to the high cathode humidity from the ΔVTR corresponding to the low cathode humidity, and take the absolute value as ΔVTR_HR; subtract the ΔVTR corresponding to the high anode back pressure from the ΔVTR corresponding to the low anode back pressure, and take the absolute value as ΔVTR_press; subtract the ΔVTR corresponding to the high cathode stoichiometric ratio from the ΔVTR corresponding to the low cathode stoichiometric ratio, and take the absolute value as ΔVTR_CaSR; subtract the ΔVTR corresponding to the high anode stoichiometric ratio from the ΔVTR corresponding to the low anode stoichiometric ratio, and take the absolute value as ΔVTR_AnSR; S9. Compare ΔVTR_temp, ΔVTR_HR, ΔVTR_press, ΔVTR_CaSR and ΔVTR_AnSR, where the largest value indicates that there is a problem with the operating condition corresponding to the value, and then compare the two corresponding ΔVTRs under the operating condition. The smaller ΔVTR value indicates that the corresponding condition is the problem point; and adjust the fuel cell stack operating conditions according to the calculation results to return the fuel cell stack to a healthy operating state.

2. The method for calculating the operating state of a fuel cell according to claim 1, wherein: In step S2, the voltage trend series under the high coolant temperature operating condition is recorded as VT k _temp_max, the voltage trend series under low coolant temperature operating conditions is recorded as VT k _temp_min, the voltage trend series under high cathode humidity operating conditions is recorded as VT k The voltage trend series under the operating conditions of _HR_max and low cathode humidity is recorded as VT k The voltage trend series under the conditions of _HR_min and high anode back pressure is recorded as VT k _press_max, the voltage trend series under low anode back pressure operating conditions is recorded as VT k _press_min, the voltage trend series under the operating conditions of high cathode stoichiometric ratio is recorded as VT k The voltage trend series under the conditions of _CaSR_max and low cathode stoichiometric ratio operation is recorded as VT k The voltage trend series under the conditions of _CaSR_min and high anode stoichiometric ratio is recorded as VT k _AnSR_max, the voltage trend series under low anode stoichiometric ratio operating conditions is recorded as VT k _AnSR_min.

3. The method for calculating the operating state of a fuel cell according to claim 2, wherein: The specific calculation of step S3 is as follows:

4. The method for calculating the fuel cell operating state according to claim 3, characterized in that: The specific calculation of step S4 is as follows:

5. The method for calculating the operating state of a fuel cell according to claim 4, wherein: The step S7 is specifically as follows: The current voltage trend rate VTR_now corresponding to high coolant temperature is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_temp_max; the current voltage trend rate VTR_now corresponding to low coolant temperature is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_temp_min; the current voltage trend rate VTR_now corresponding to high cathode humidity is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_HR_max; the current voltage trend rate VTR_now corresponding to low cathode humidity is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_HR_min; the current voltage trend rate VTR_now corresponding to high anode back pressure is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_max; the current voltage trend rate VTR_now corresponding to low anode back pressure is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_max; The corresponding current voltage trend rate VTR_now is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_press_min; the current voltage trend rate VTR_now corresponding to the high cathode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_CaSR_max; the current voltage trend rate VTR_now corresponding to the low cathode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_CaSR_min; the current voltage trend rate VTR_now corresponding to the high anode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_AnSR_max; the current voltage trend rate VTR_now corresponding to the low anode stoichiometric ratio is subtracted from the reference voltage trend rate VTR_ref, and the result is recorded as ΔVTR_AnSR_min; the specific calculation is as follows:

6. The method for calculating the operating state of a fuel cell according to claim 5, characterized in that: The specific calculation of step S8 is as follows:

Images