A method and testing system for determining the lifespan of an electric vehicle contactor.

Abstract

This application provides a method and testing system for determining the lifespan of an electric vehicle contactor. The method for determining the lifespan of an electric vehicle contactor includes: acquiring the voltage and current values ​​of the target contactor while it is in a closed state in the battery pack under test; determining the impedance value of the target contactor based on the voltage and current values; determining the optimal service life of the target contactor at the current number of closures based on the impedance value and the number of closures of the target contactor; and determining the remaining lifespan of the target contactor based on the optimal service life at the current number of closures and the preset service life of the target contactor. This application improves the accuracy of determining the remaining lifespan and aging degree of the target contactor.

Description

Technical Field

[0001] This application relates to the field of new energy electric vehicle technology, and in particular to a method and testing system for determining the lifespan of an electric vehicle contactor. Background Technology

[0002] With the expansion of the new energy market, new energy electric vehicles are becoming increasingly popular among users. As a result, various safety issues of electric vehicles have become particularly important. In response, many vehicle manufacturers have proposed to test and determine the service life of contactors.

[0003] However, in the current market, most vehicle manufacturers calculate the aging and service life of contactors based on the current value when the contactor is disconnected. However, since the current value of the contactor is different each time it is disconnected, the accuracy of this calculation method is low. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method and detection system for determining the life of an electric vehicle contactor, which improves the accuracy of determining the remaining life and aging degree of the target contactor.

[0005] This application provides a method for determining the lifespan of an electric vehicle contactor. The method and detection system for determining the lifespan of an electric vehicle contactor include:

[0006] With the target contactor in the battery pack to be tested in a closed state, the voltage and current values ​​of the target contactor are acquired.

[0007] The impedance value of the target contactor is determined based on the voltage value and the current value.

[0008] Based on the impedance value and the number of times the target contactor has closed, determine the optimal service life of the target contactor at the current number of closures;

[0009] The remaining lifespan of the target contactor is determined based on the optimal service life of the target contactor at the current number of closing cycles and the preset service life of the target contactor.

[0010] Furthermore, determining the optimal service life of the target contactor at the current number of closures based on the impedance value and the number of closures of the target contactor includes:

[0011] Based on the number of times the target contactor is closed, the lifespan increase of the target contactor after each closure, and the lifespan of the target contactor before the current number of closures, the initial lifespan of the target contactor at the current number of closures is determined;

[0012] Based on the initial service life of the target contactor at the current number of closures, the impedance value of the target contactor, and the error covariance of the target contactor, the optimal service life of the target contactor at the current number of closures is determined.

[0013] Furthermore, based on the number of times the target contactor has closed, the lifespan increase of the target contactor after each closure, and the lifespan of the target contactor before the current number of closures, the initial service life of the target contactor at the current number of closures is determined, including:

[0014] Based on the number of times the target contactor is closed and the lifespan increase of the target contactor after each closure, determine the total lifespan increase of the target contactor under the current number of closures;

[0015] The initial service life of the target contactor at the current number of closures is determined based on the total lifespan increase and the lifespan of the target contactor before the current number of closures.

[0016] Furthermore, the error covariance comprises the process noise covariance and the measurement noise covariance. Determining the optimal service life of the target contactor based on its initial service life at the current number of closures, its impedance value, and the error covariance of the target contactor includes:

[0017] The initial service life covariance of the target contactor is determined based on the initial service life of the target contactor at the current number of closures and the process noise covariance.

[0018] The initial service life weighting coefficient of the target contactor is determined based on the initial service life of the target contactor at the current number of closures and the measurement noise covariance.

[0019] Based on the initial service life covariance, the initial service life weighting coefficient, and the impedance value of the target contactor, the optimal service life of the target contactor under the current number of closing operations is determined.

[0020] Furthermore, determining the optimal service life of the target contactor based on the initial service life covariance, the initial service life weighting coefficient, and the impedance value of the target contactor includes:

[0021] The internal resistance life of the target contactor at the specified impedance value is determined based on the impedance value of the target contactor and the number of times the target contactor is closed.

[0022] Based on the target contactor's internal resistance life, initial service life covariance, initial service life weighting coefficient, and initial service life, determine the target contactor's optimal service life for the current number of closing cycles.

[0023] Furthermore, after determining the remaining lifespan of the target contactor based on its optimal service life at the current number of closing cycles and its preset service life, the method for determining the lifespan of the electric vehicle contactor further includes:

[0024] The remaining lifespan of the target contactor is compared with the preset contactor threshold lifespan to determine whether the target contactor is aging.

[0025] If the remaining lifespan of the target contactor is greater than or equal to the preset contactor threshold lifespan, then the target contactor is determined to be aged.

[0026] If the remaining lifespan of the target contactor is less than the preset contactor threshold lifespan, then the target contactor is determined not to be aged.

[0027] This application embodiment also provides a detection system for the life of an electric vehicle contactor. The detection system for the life of an electric vehicle contactor includes a target contactor assembly and a BMS, wherein the target contactor assembly is connected to the BMS.

[0028] The target contactor assembly includes a target contactor, an MCU, an optocoupler switch, an amplifier, and a target contactor power supply coil;

[0029] The BMS is electrically connected to the MCU, the MCU is connected to the output terminal of the amplifier, and the output terminal of the amplifier is grounded. The positive input terminal of the amplifier is connected to one end of the target contactor through the optocoupler switch, and the negative input terminal of the amplifier is connected to the other end of the target contactor. Both ends of the target contactor are connected to the power supply coil of the target contactor.

[0030] Furthermore, the electric vehicle contactor life detection system also includes a pull-down resistor, one end of which is connected to the MCU, and the other end of which is connected to the output of the amplifier.

[0031] This application also provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the method for determining the life of an electric vehicle contactor as described above are performed.

[0032] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the method for determining the lifespan of an electric vehicle contactor as described above.

[0033] The method and detection system for determining the lifespan of electric vehicle contactors provided in this application, compared with the contactor lifespan methods in the prior art, calculate the impedance value of the target contactor in the battery pack to be tested, and determine the optimal service life of the target contactor under the current number of closures based on the impedance value and the number of closures of the target contactor. This improves the accuracy of determining the remaining lifespan and aging degree of the target contactor, ensuring the normal use of the target contactor while avoiding failure caused by continued use of the target contactor after aging.

[0034] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart of one of the methods for determining the lifespan of an electric vehicle contactor provided in an embodiment of this application is shown;

[0037] Figure 2 A second flowchart of a method for determining the lifespan of an electric vehicle contactor provided in an embodiment of this application is shown;

[0038] Figure 3 A schematic diagram of the structure of a contactor life detection system for electric vehicles provided in an embodiment of this application is shown;

[0039] Figure 4 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown.

[0040] In the picture:

[0041] 300 - Electric vehicle contactor life detection system; 310 - Target contactor assembly; 311 - Target contactor; 312 - MCU; 313 - Amplifier; 314 - Target contactor power supply coil; 315 - Pull-down resistor; 316 - Optocoupler switch; 320 - BMS; 400 - Electronic equipment; 410 - Processor; 420 - Memory; 430 - Bus. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0043] First, the applicable scenarios for this application will be introduced. This application can be applied to the field of new energy electric vehicle technology.

[0044] Research has found that most vehicle manufacturers currently calculate the aging and lifespan of contactors based on the current value when the contactor disconnects. However, because the current value varies each time the contactor disconnects, this calculation method has low accuracy.

[0045] Furthermore, in the prior art, a relationship diagram between the number of contactor closings and its lifespan and a relationship diagram between the contactor impedance value and its lifespan are usually obtained. However, the number of contactor closings alone cannot represent the actual lifespan of the contactor. Its lifespan is determined by its impedance value. Therefore, the embodiments provided in this application introduce impedance value calculation to correct the remaining lifespan of the counted contactor.

[0046] Based on this, embodiments of this application provide a method and detection system for determining the lifespan of an electric vehicle contactor, which improves the accuracy of the remaining lifespan and aging degree of the target contactor.

[0047] Please see Figure 1 , Figure 1 This is one of the flowcharts illustrating a method for determining the lifespan of an electric vehicle contactor, as provided in an embodiment of this application. Figure 1 As shown in the figure, the method for determining the lifespan of an electric vehicle contactor provided in this application includes the following steps:

[0048] S101. With the target contactor in the battery pack to be tested in a closed state, acquire the voltage and current values ​​of the target contactor.

[0049] In this step, when the vehicle needs to close the target contactor, the BMS supplies power to the target contactor's power supply coil and the MCU to close the target contactor and wake up the MCU. At this time, the MCU starts to collect the voltage across the target contactor, and the BMS sends the detected current value to the MCU.

[0050] S102. Determine the impedance value of the target contactor based on the voltage value and the current value.

[0051] In this step, the MCU calculates the impedance value of the target contactor based on the voltage values ​​collected at both ends of the contact and the current values ​​received from the BMS.

[0052] S103. Based on the impedance value and the number of times the target contactor has closed, determine the optimal service life of the target contactor at the current number of closures.

[0053] In this step, the optimal service life of the target contactor under the current number of closing cycles is determined based on the number of closing cycles of the target contactor, the impedance value of the target contactor, and the preset Kalman filter algorithm.

[0054] Thus, Kalman filtering is an algorithm that uses the state equations of a linear system to make an optimal estimate of the system state using the system's input and output observation data. Since the observation data includes the effects of noise and interference in the system, the optimal estimation can also be regarded as a filtering process.

[0055] Data filtering is a data processing technique that removes noise and restores accurate data. Kalman filtering, when the measurement variance is known, can estimate the state of a dynamic system from a series of data containing measurement noise. Because it is easy to implement in computer programming and can update and process field-acquired data in real time, Kalman filtering is currently the most widely used filtering method, finding good applications in communication, navigation, guidance, and control, among other fields.

[0056] Thus, step S103 includes the following sub-steps:

[0057] Sub-step 1031: Based on the number of times the target contactor is closed, the lifespan increase of the target contactor after each closure, and the lifespan of the target contactor before the current number of closures, determine the initial lifespan of the target contactor at the current number of closures.

[0058] The formula for the initial service life of the target contactor under the current number of closing cycles is as follows:

[0059] Xp(t)=A*X(t-1)+B*U(t)+W(t);

[0060] Where Xp(t) is used to characterize the initial service life of the target contactor under t closures; A is used to characterize the state transition matrix; B is used to characterize the input matrix; X(t) is used to characterize the service life of the target contactor before t closures; U(t) is used to characterize the increase in service life of the target contactor after t closures; t is used to characterize the number of closures; and W(t) is used to characterize the process noise.

[0061] Here, sub-step S1031 includes the following sub-steps:

[0062] Sub-step S10311: Determine the total lifespan increase of the target contactor under the current number of closures based on the number of closures of the target contactor and the lifespan increase of the target contactor after each closure.

[0063] In this step, the formula for the total lifespan increase of the target contactor under the current number of closing cycles is as follows:

[0064] U(t) = mt;

[0065] Where t represents the number of closures; U(t) represents the increase in lifespan of the target contactor after t closures; and m represents the increase in lifespan of the target contactor after each closure.

[0066] Sub-step S10312: Based on the total lifespan increase and the lifespan of the target contactor before the current number of closures, determine the initial lifespan of the target contactor at the current number of closures.

[0067] Sub-step 1032: Based on the initial service life of the target contactor under the current number of closures, the impedance value of the target contactor, and the error covariance of the target contactor, determine the optimal service life of the target contactor under the current number of closures.

[0068] In this step, the error covariance is the process noise covariance and the measurement noise covariance, and the process noise covariance provided in this application is represented by Q(t), and the measurement noise covariance provided in this application is represented by H(t).

[0069] Here, covariance is used in probability theory and statistics to measure the population error between two variables. Variance is a special case of covariance, that is, when the two variables are the same.

[0070] Covariance represents the overall error between two variables, unlike variance, which represents the error of only one variable. If the two variables have the same trend—that is, if one is greater than its expected value and the other is also greater than its expected value—then the covariance between the two variables is positive. If the two variables have opposite trends—that is, one is greater than its expected value and the other is less than its expected value—then the covariance between the two variables is negative.

[0071] Sub-step 1032 includes the following sub-steps:

[0072] Sub-step 10321: Determine the initial service life covariance of the target contactor based on the initial service life of the target contactor at the current number of closing cycles and the process noise covariance.

[0073] In this step, the formula for the initial used service life covariance of the target contactor is as follows:

[0074] Pp(t)=A*P(t-1)*Xp(t)+Q(t);

[0075] Wherein, Pp(t) is used to characterize the initial service life covariance; P(t) is the service life error covariance after t closure cycles; and Q(t) is used to characterize the process noise covariance.

[0076] Sub-step 10322: Determine the initial service life weighting coefficient of the target contactor based on the initial service life of the target contactor under the current number of closing cycles and the measurement noise covariance.

[0077] In this step, the initial service life weighting coefficient of the target contactor in the embodiments provided in this application can be specifically, but is not limited to, the Kalman gain coefficient. That is, the embodiments provided in this application select the Kalman filter algorithm for correction calculation, and the Kalman filter function is a single model with only service life values. The measurement method is resistance lookup table. Therefore, the observation matrix is ​​set to 1.

[0078] The formula for the initial service life weighting coefficient of the target contactor is as follows:

[0079] Kg(t)=Pp(t)*Xp(t) / (A*Pp(t)*Xp(t)+H(t));

[0080] Wherein, Pp(t) is used to characterize the initial used life covariance; H(t) is used to characterize the measurement noise covariance.

[0081] Sub-step 10323: Based on the initial service life covariance, the initial service life weighting coefficient, and the impedance value of the target contactor, determine the optimal service life of the target contactor under the current number of closing operations.

[0082] In this step, the internal resistance life of the target contactor at the impedance value and the number of times the target contactor is closed is determined. Based on the internal resistance life, initial service life covariance, initial service life weighting coefficient, and initial service life, the optimal service life of the target contactor at the current number of closures is determined.

[0083] Here, the formula for the optimal service life of the target contactor under the current number of closing cycles is:

[0084] X0(t)=Xp(t)+Kg(t)*[Z(t)–A*Xp(t)];

[0085] Z(t) = A*X(t) + R(t);

[0086] Where X0(t) is used to characterize the optimal service life of the target contactor at the current number of closing cycles; Z(t) is used to characterize the internal resistance life of the target contactor at this impedance value; and R(t) is used to characterize the impedance value after t closing cycles.

[0087] In determining the optimal lifetime for the current number of closures, it is necessary to continuously update the covariance of the optimal lifetime for the current number of closures. The specific formula is as follows:

[0088] P0(t)=(1-Kg(t)*A)*Pp(t);

[0089] Wherein, P0(t) is used to characterize the covariance of the optimal lifetime under the updated current number of closures.

[0090] Below, we will use a specific example to illustrate the calculation process of the optimal lifetime under the current number of closures:

[0091] Assume that the state transition matrix A, input matrix B, and observation matrix are all 1, and the lifespan of the target contactor increases by m after each closure. The lifespan of the target contactor before t closures is X(t) = 0, the number of closures is t = 1, the process noise covariance is Q(1) = Q, the measurement noise covariance is H(1) = H, the initial lifespan covariance is Pp(t) = σ22, the lifespan error covariance after t closures is P(t) = σ12, and P(0) = σ12 = 1. The internal resistance lifespan of the target contactor at this impedance value is Z(1) = S.

[0092] Therefore, the optimal service life of the target contactor under the current number of closing cycles is:

[0093] Xp(t)=A*X(t-1)+B*U(t)+W(t);

[0094] U(t) = mt;

[0095] Xp(1)=1*u1+1*U(t)=0+m=m.

[0096] The initial used life covariance is:

[0097] Pp(t)=A*P(t-1)*Xp(t)+Q(t);

[0098] Pp(1)=σ22=1*σ12*1+Q(t)=1+Q.

[0099] The initial used life weighting factor is:

[0100] Kg(t)=Pp(t)*Xp(t) / (A*Pp(t)*Xp(t)+H(t));

[0101] Kg(1)=σ22*1 / (1*σ22*1+H(t))=(1+Q) / (1+Q+H).

[0102] The optimal service life of the target contactor under the current number of closing cycles is:

[0103] X0(t)=Xp(t)+Kg(t)*[Z(t)–A*Xp(t)];

[0104] Z(t) = A*X(t) + R(t);

[0105] X0(t)=m+[(Sm)*(1+Q)] / (1+Q+H).

[0106] And the covariance of the optimal lifetime under the updated current number of closures is:

[0107] P0(t)=(1-Kg(t)*A)*Pp(t);

[0108] P0(t)=(1-A*(1+Q) / (1+Q+H))*1+Q.

[0109] S104. Based on the optimal service life of the target contactor under the current number of closing cycles and the preset service life of the target contactor, determine the remaining service life of the target contactor.

[0110] In this step, the remaining lifespan of the target contactor can be obtained by subtracting its optimal service life from the target contactor's current number of closing cycles from its preset service life.

[0111] The method for determining the lifespan of an electric vehicle contactor provided in this application, compared with the prior art, calculates the impedance value of the target contactor in the battery pack to be tested, and determines the optimal service life of the target contactor at the current number of closing cycles based on the impedance value and the number of closing cycles of the target contactor. This improves the accuracy of determining the remaining lifespan and aging degree of the target contactor, ensuring the normal use of the target contactor while avoiding failure caused by continued use after aging.

[0112] Please see Figure 2 , Figure 2 This is a second flowchart illustrating a method for determining the lifespan of an electric vehicle contactor, provided as an embodiment of this application. Figure 2 As shown in the figure, the method for determining the lifespan of an electric vehicle contactor provided in this application includes the following steps:

[0113] S201. With the target contactor in the battery pack to be tested in a closed state, acquire the voltage and current values ​​of the target contactor.

[0114] S202. Determine the impedance value of the target contactor based on the voltage value and the current value.

[0115] S203. Based on the impedance value and the number of times the target contactor has closed, determine the optimal service life of the target contactor at the current number of closures.

[0116] S204. Based on the optimal service life of the target contactor under the current number of closing cycles and the preset service life of the target contactor, determine the remaining service life of the target contactor.

[0117] S205. Compare the remaining lifespan of the target contactor with the preset contactor threshold lifespan to determine whether the target contactor is aging.

[0118] S206. If the remaining lifespan of the target contactor is greater than or equal to the preset contactor threshold lifespan, then the target contactor is determined to be aged.

[0119] In this step, after determining that the target contactor is aging, feedback is sent to the BMS. At this time, the BMS prohibits the target contactor from closing again to ensure the normal use of the target contactor under high voltage conditions.

[0120] S207. If the remaining lifespan of the target contactor is less than the preset contactor threshold lifespan, then it is determined that the target contactor is not aged.

[0121] In this step, after confirming that the target contactor is not aged, feedback is sent to the BMS, at which point the BMS allows the target contactor to close again.

[0122] The descriptions of S201 to S204 can be referred to those of S101 to S104, and the same technical effect can be achieved, so they will not be elaborated further.

[0123] The method for determining the lifespan of an electric vehicle contactor provided in this application, compared with the prior art, calculates the impedance value of the target contactor in the battery pack to be tested, and determines the optimal service life of the target contactor at the current number of closing cycles based on the impedance value and the number of closing cycles of the target contactor. This improves the accuracy of determining the remaining lifespan and aging degree of the target contactor, ensuring the normal use of the target contactor while avoiding failure caused by continued use after aging.

[0124] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a contactor life detection system for electric vehicles provided in an embodiment of this application, as shown below. Figure 3 As shown, the electric vehicle contactor life detection system 300 includes a target contactor assembly 310 and a BMS 320, wherein the target contactor assembly 310 is connected to the BMS 320.

[0125] The target contactor assembly 310 includes a target contactor 311, an MCU 312, an optocoupler switch 316, an amplifier 313, and a target contactor power supply coil 314.

[0126] The BMS320 is electrically connected to the MCU312, the MCU312 is connected to the output terminal of the amplifier 313, and the output terminal of the amplifier 313 is grounded. The positive input terminal of the amplifier 313 is connected to one end of the target contactor 311 through the optocoupler switch 316, and the negative input terminal of the amplifier 313 is connected to the other end of the target contactor 311. The two ends of the target contactor 311 are connected to the target contactor power supply coil 314.

[0127] The electric vehicle contactor life detection system 300 also includes a pull-down resistor 315, one end of which is connected to the MCU 312, and the other end of which is connected to the output of the amplifier 313.

[0128] The BMS320 is used to control the target contactor 311 to close and supply power to the target contactor power supply coil 314 and the MCU312 when the target contactor 311 in the battery pack to be tested is being tested, and to send the current value used during power supply to the MCU312.

[0129] The MCU312 is used to control the optocoupler switch 316 to close after the BMS320 is powered, and to obtain the voltage value across the target contactor 311, and to determine the impedance value of the target contactor 311 based on the voltage value and the current value.

[0130] The MCU312 is further configured to determine the optimal service life of the target contactor 311 at the current number of closing cycles based on the impedance value and the number of closing cycles of the target contactor 311, and to determine the remaining service life of the target contactor 311 based on the optimal service life of the target contactor 311 at the current number of closing cycles and the preset service life of the target contactor.

[0131] The MCU312 is further configured to compare the remaining lifespan of the target contactor 311 with a preset contactor threshold lifespan to determine whether the target contactor is aging; if the remaining lifespan of the target contactor 311 is greater than or equal to the preset contactor threshold lifespan, then the target contactor 311 is determined to be aging; if the remaining lifespan of the target contactor 311 is less than the preset contactor threshold lifespan, then the target contactor 311 is determined not to be aging.

[0132] Working principle: When the vehicle needs to close the target contactor 311, the BMS320 supplies power to the target contactor power supply coil 314 and MCU312 to close the target contactor 311 and wake up the MCU312. At this time, the MCU312 controls the optocoupler switch 316 to close and begins to collect the voltage across the target contactor 311. The MCU312 calculates the impedance value of the target contactor 311 based on the collected voltage across the contact and the current value received from the BMS320. Based on the impedance value and the number of times the target contactor 311 has closed, the MCU312 determines the target contactor's impedance value. The MCU312 determines the remaining lifespan of the target contactor 311 based on the optimal service life of the target contactor 311 under the current number of closing cycles and the preset service life of the target contactor 311. The remaining lifespan of the target contactor 311 is compared with the preset contactor threshold lifespan to determine whether the target contactor 311 is aging. After determining the target contactor 311, the MCU312 feeds back to the BMS320. At this time, the BMS320 prohibits the target contactor 311 from closing again to ensure the normal use of the target contactor 311 under high voltage conditions.

[0133] The electric vehicle contactor life detection system 300 provided in this application embodiment, compared with the prior art for determining contactor life, calculates the impedance value of the target contactor 311 in the battery pack to be tested, and determines the optimal service life of the target contactor 311 under the current number of closing based on the impedance value and the number of closing times of the target contactor 311, thereby determining the remaining life and aging degree of the target contactor 311. This improves the accuracy of determining the remaining life and aging degree of the target contactor 311, ensuring the normal use of the target contactor 311 while avoiding failure caused by continued use of the target contactor 311 after aging.

[0134] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 400 includes a processor 410, a memory 420, and a bus 430.

[0135] The memory 420 stores machine-readable instructions executable by the processor 410. When the electronic device 400 is running, the processor 410 communicates with the memory 420 via the bus 430. When the machine-readable instructions are executed by the processor 410, they can perform the operations described above. Figure 1 as well as Figure 2The steps of the method for determining the lifespan of the electric vehicle contactor in the illustrated method embodiment can be found in the method embodiment for specific implementation, and will not be repeated here.

[0136] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 as well as Figure 2 The steps of the method for determining the lifespan of the electric vehicle contactor in the illustrated method embodiment can be found in the method embodiment for specific implementation, and will not be repeated here.

[0137] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0138] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0139] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0140] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0141] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0142] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the lifespan of an electric vehicle contactor, characterized in that, The method for determining the lifespan of the electric vehicle contactor includes: With the target contactor in the battery pack to be tested in a closed state, the voltage and current values ​​of the target contactor are acquired. The impedance value of the target contactor is determined based on the voltage value and the current value. Based on the impedance value and the number of times the target contactor has closed, determine the optimal service life of the target contactor at the current number of closures; The remaining lifespan of the target contactor is determined based on the optimal service life of the target contactor under the current number of closing cycles and the preset service life of the target contactor. Determining the optimal service life of the target contactor at the current number of closures, based on the impedance value and the number of closures of the target contactor, includes: Based on the number of times the target contactor is closed, the lifespan increase of the target contactor after each closure, and the lifespan of the target contactor before the current number of closures, the initial lifespan of the target contactor at the current number of closures is determined; The initial service life of the target contactor at the current number of closures is determined by the following formula: Xp(t) = A*X(t-1) + B*U(t) + W(t); Where Xp(t) is used to characterize the initial service life of the target contactor under t closures; A is used to characterize the state transition matrix; B is used to characterize the input matrix; X(t) is used to characterize the service life of the target contactor before t closures; U(t) is used to characterize the increase in service life of the target contactor after t closures; t is used to characterize the number of closures; W(t) is used to characterize the process noise. Based on the initial service life of the target contactor at the current number of closures, the impedance value of the target contactor, and the error covariance of the target contactor, the optimal service life of the target contactor at the current number of closures is determined; The optimal service life of the target contactor under the current number of closing cycles is determined by the following formula: X0(t) =Xp(t) + Kg(t)*[ Z(t) – A* Xp(t) ]; Z(t) = A*X(t) + R(t); Where X0(t) is used to characterize the optimal service life of the target contactor under the current number of closing cycles; Z(t) is used to characterize the internal resistance life of the target contactor under this impedance value; R(t) is used to characterize the impedance value after t closing cycles; Kg(t) is the initial service life weighting coefficient of the target contactor.

2. The method for determining the lifespan of an electric vehicle contactor according to claim 1, characterized in that, Based on the number of closures of the target contactor, the lifespan increase of the target contactor after each closure, and the lifespan of the target contactor before the current number of closures, the initial service life of the target contactor at the current number of closures is determined, including: Based on the number of times the target contactor is closed and the lifespan increase of the target contactor after each closure, determine the total lifespan increase of the target contactor under the current number of closures; The initial service life of the target contactor at the current number of closures is determined based on the total lifespan increase and the lifespan of the target contactor before the current number of closures.

3. The method for determining the lifespan of an electric vehicle contactor according to claim 1, characterized in that, The error covariance is the process noise covariance and the measurement noise covariance. Determining the optimal service life of the target contactor based on its initial service life at the current number of closures, its impedance value, and the error covariance of the target contactor includes: The initial service life covariance of the target contactor is determined based on the initial service life of the target contactor at the current number of closures and the process noise covariance. The initial service life weighting coefficient of the target contactor is determined based on the initial service life of the target contactor at the current number of closures and the measurement noise covariance. Based on the initial service life covariance, the initial service life weighting coefficient, and the impedance value of the target contactor, the optimal service life of the target contactor under the current number of closing operations is determined.

4. The method for determining the lifespan of an electric vehicle contactor according to claim 3, characterized in that, The step of determining the optimal service life of the target contactor for the current number of closing operations, based on the initial service life covariance, the initial service life weighting coefficient, and the impedance value of the target contactor, includes: The internal resistance life of the target contactor at the specified impedance value is determined based on the impedance value of the target contactor and the number of times the target contactor is closed. Based on the target contactor's internal resistance life, initial service life covariance, initial service life weighting coefficient, and initial service life, determine the target contactor's optimal service life for the current number of closing cycles.

5. The method for determining the lifespan of an electric vehicle contactor according to claim 1, characterized in that, After determining the remaining lifespan of the target contactor based on its optimal service life at the current number of closing cycles and its preset service life, the method for determining the lifespan of the electric vehicle contactor further includes: The remaining lifespan of the target contactor is compared with the preset contactor threshold lifespan to determine whether the target contactor is aging. If the remaining lifespan of the target contactor is greater than or equal to the preset contactor threshold lifespan, then the target contactor is determined to be aged. If the remaining lifespan of the target contactor is less than the preset contactor threshold lifespan, then the target contactor is determined not to be aged.

6. A system for detecting the lifespan of an electric vehicle contactor, characterized in that, The method for determining the lifespan of an electric vehicle contactor according to any one of claims 1-5, wherein the detection system for the lifespan of the electric vehicle contactor includes a target contactor assembly and a BMS, wherein the target contactor assembly is connected to the BMS; The target contactor assembly includes a target contactor, an MCU, an optocoupler switch, an amplifier, and a target contactor power supply coil; The BMS is electrically connected to the MCU, the MCU is connected to the output terminal of the amplifier, and the output terminal of the amplifier is grounded. The positive input terminal of the amplifier is connected to one end of the target contactor through the optocoupler switch, and the negative input terminal of the amplifier is connected to the other end of the target contactor. Both ends of the target contactor are connected to the power supply coil of the target contactor.

7. The electric vehicle contactor life detection system according to claim 6, characterized in that, The electric vehicle contactor life detection system also includes a pull-down resistor, one end of which is connected to the MCU and the other end of which is connected to the output of the amplifier.

8. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. The machine-readable instructions are executed by the processor to perform the steps of the method for determining the life of an electric vehicle contactor as described in any one of claims 1-5.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the method for determining the lifespan of an electric vehicle contactor as described in any one of claims 1-5.

Images