Test apparatus and test method for power battery charger and electronic device

Abstract

A test device (120) and test method for a power battery charger (110) and an electronic device, solving the problem that the result of a simulating battery is inaccurate during the test of a power battery charger (110), providing an active inverter module (124) for a simulating load (122) so as to allow for a controllable output end voltage amplitude, and reflecting a charging state on the basis of an OCV-SOC curve and an SOC-quantity-of-charge curve of an actual battery under test so as to allow for a more accurate and real result of the simulating battery during the test of the charger (110).

Description

A test device, test method and electronic equipment for a power battery charger

[0001] This application claims priority to the invention patent application filed with the State Intellectual Property Office of China on November 27, 2023, with Chinese application number 202311589476.9 and invention name “A testing device, testing method and electronic device for a power battery charger”, and all its contents are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of electric energy storage systems, and in particular to a testing device, a testing method, and an electronic device for a power battery charger. Background Art

[0003] Lithium-ion batteries are widely used as power batteries due to their high energy density and low pollution levels. However, testing lithium-ion battery chargers places high demands on battery safety. Overheating, overcurrent, and overvoltage can damage the battery. Using a simulated battery can identify charger issues in advance, avoiding potential damage during real-world battery testing. However, the parameters of simulated batteries are limited and do not accurately reflect the performance of actual batteries.

[0004] Therefore, during the charger testing process, how to more accurately simulate the actual battery conditions becomes an urgent problem to be solved.

[0005] Summary of the Invention

[0006] The present application provides a testing device, a testing method, and an electronic device for a power battery charger, which can more accurately simulate the actual battery conditions during the charger testing process.

[0007] In a first aspect, a test device for a power battery charger is provided, the test device is used to simulate a battery to be tested to be charged, and the test device includes: an input end, the charger inputs electric energy to the test device through the input end; a simulated load, the access end of the simulated load is connected to the input end, the simulated load includes a first resistor, a second resistor and a first capacitor, the simulated load is used to simulate the charging load of the battery, wherein the second resistor and the first capacitor are connected in parallel, and the two ends after parallel connection are respectively connected to one end of the first resistor and the output end of the simulated load, and the other end of the first resistor is connected to the access end of the simulated load; an active inverter module, the access end of the active inverter module is connected to the output end of the simulated load, and the output end of the active inverter module is used to output alternating current; a battery management system, the battery management system is used to obtain the open-circuit voltage (OCV)-battery state of charge (SC) of the battery to be tested. The method comprises the steps of: sampling a first current at the input terminal and integrating the first current within a first time period to obtain the charge of the battery to be tested; determining the SOC of the battery to be tested based on the charge of the battery to be tested and the SOC-charge curve; sampling a second current at the access terminal of the active inverter module at a first moment, determining the Uoc of the battery to be tested based on the SOC of the battery to be tested and the OCV-SOC curve, and determining a first voltage at the output terminal of the active inverter module based on the Uoc, the resistance value of the first resistor, the resistance value of the second resistor, and the second current, wherein the first moment is the last moment of the first time period; controlling the active inverter module to adjust the effective value of the voltage at the output terminal to the first voltage at a second moment, wherein the time that the second moment lags behind the first moment is a first time interval; sampling the current and voltage of the input terminal at the second moment, determining whether there is overcurrent based on whether the current of the input terminal is greater than a first threshold value, and determining whether there is overvoltage or undervoltage based on the relationship between the voltage of the input terminal and a preset condition.

[0008] In the embodiment provided in the present application, the charger test device can adjust the output voltage amplitude of the output end by connecting an active inverter module to the output end of the simulated load, and then match the open circuit voltage value according to the obtained OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested, so that the apparent parameters of the test device are closer to the actual battery situation, thereby achieving the purpose of more realistic simulation of the battery to be tested.

[0009] In combination with the first aspect, in certain implementations of the first aspect, the battery management system is also used to obtain the relationship between the battery health (SOH) of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitor of the battery to be tested, and determine the resistance value of the first resistor, the resistance value of the second resistor, and the capacitance value of the first capacitor according to the expected SOH of the battery to be tested, wherein the resistance value of the first resistor is the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the second resistor is the resistance value of the equivalent polarization resistance of the battery to be tested, and the capacitance value of the first capacitor is the capacitance value of the equivalent polarization capacitor of the battery to be tested.

[0010] In the embodiment provided in the present application, the testing device of the charger obtains the relationship between the SOH and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitor, and then changes the battery simulation parameters in the simulated load according to the relationship, so that the testing device can simulate batteries to be tested with different degrees of aging, thereby achieving the purpose of more realistic simulation of the battery to be tested.

[0011] In combination with the first aspect and certain implementations of the first aspect, the alternating current output from the output end of the active inverter module is output to the power grid after reactive power compensation.

[0012] In combination with the first aspect and certain implementations of the first aspect, in other implementations of the first aspect, the battery management system is further used to: obtain a curve of the temperature change of the battery to be tested over time under a specific current, and determine the temperature of the battery to be tested at a third moment based on the curve of the temperature change of the battery to be tested over time under the specific current and the first current collected during the second time period, wherein the third moment is the last moment in the second time period.

[0013] In the embodiment provided in the present application, by obtaining a curve of the temperature change of the battery to be tested over time at a specific current, the temperature change of the battery to be tested during the charging process can be simulated, thereby introducing the temperature variable into the test process of the charger, and the test result is more accurate.

[0014] In combination with the first aspect and certain implementations of the first aspect, in other implementations of the first aspect, the battery management system is further used to: determine whether to issue an overtemperature alarm based on whether the temperature of the battery to be tested at the third moment is greater than a second threshold.

[0015] In combination with the first aspect and certain implementations of the first aspect, in other implementations of the first aspect, obtaining the OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested includes: obtaining the OCV-SOC curve and the SOC-charge curve of the battery to be tested at the temperature of the battery to be tested at the third moment.

[0016] The embodiments provided in the present application make the apparent parameters of the simulated battery to be tested conform to the temperature changes during the charging process by considering the influence of temperature on the OCV-SOC curve and the SOC-charge curve of the battery to be tested, thereby further improving the accuracy of the test results.

[0017] In combination with the first aspect and certain implementations of the first aspect, in other implementations of the first aspect, the battery management system is further used to: obtain a curve of the temperature change of the battery to be tested over time under a specific current, and determine the temperature of the battery to be tested at a fourth moment based on the curve of the temperature change of the battery to be tested over time under a specific current and the first current collected during the third time period, wherein the fourth moment is the last moment in the third time period; obtain the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitor, including: obtaining the relationship between the SOH of the battery to be tested at the temperature and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitor based on the temperature of the battery to be tested at the fourth moment.

[0018] In the embodiments provided in the present application, by considering the influence of temperature on the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitance of the battery to be tested, the apparent parameters of the simulated battery to be tested are made consistent with the temperature changes during the charging process, thereby further improving the accuracy of the test results.

[0019] In combination with the first aspect and certain implementations of the first aspect, in other implementations of the first aspect, controlling the active inverter module to adjust the effective value of the voltage at the output end to the first voltage at the second moment includes: controlling the duty cycle of the switching tube in the active inverter module so that the effective value of the voltage at the output end is adjusted to the first voltage at the second moment.

[0020] In combination with the first aspect and certain implementations of the first aspect, in other implementations of the first aspect, the battery management system is also used to: when the first voltage is greater than a third threshold, set the first time interval to a second time interval, and the second time interval is greater than the first time interval.

[0021] In a second aspect, a test method for a power battery charger is provided, which is applied to a test device for a power battery charger, wherein the test device includes: an input end, a simulated load, an access end of the simulated load is connected to the input end, the simulated load includes a first resistor, a second resistor and a first capacitor, and the simulated load is used to simulate the charging load of the battery, wherein the second resistor and the first capacitor are connected in parallel, and the two ends after parallel connection are respectively connected to one end of the first resistor and the output end of the simulated load, and the other end of the first resistor is connected to the access end of the simulated load, wherein the charger inputs electric energy to the test device through the input end; an active inverter module, the access end of the active inverter module is connected to the output end of the simulated load; a battery management system; the test method includes: the battery management system obtains the OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested; samples the first current of the input end of the test device, and integrates the first current in a first time period to obtain the electric current of the battery to be tested. The method comprises the steps of: sampling a second current at the access end of the active inverter module at a first moment, determining the Uoc of the battery to be tested according to the SOC of the battery to be tested and the OCV-SOC curve, and determining a first voltage at the output end of the active inverter module according to the Uoc, the resistance value of the first resistor, the resistance value of the second resistor, and the second current, wherein the first moment is the last moment of the first time period, the resistance value of the first resistor is the resistance value of the equivalent internal resistance of the battery to be tested, and the resistance value of the second resistor is the resistance value of the equivalent polarization resistance of the battery to be tested; controlling the active inverter module to adjust the effective value of the voltage at the output end to the first voltage at a second moment, wherein the time that the second moment lags behind the first moment is a first time interval; sampling the current and voltage of the input end at the second moment, determining whether there is overcurrent according to whether the current of the input end is greater than a first threshold value, and determining whether there is overvoltage or undervoltage according to the relationship between the voltage of the input end and a preset condition.

[0022] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, the method also includes: the battery management system obtains the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitor, and determines the resistance value of the first resistor, the resistance value of the second resistor and the capacitance value of the first capacitor according to the expected SOH of the battery to be tested, wherein the capacitance value of the first capacitor is the capacitance value of the equivalent polarization capacitor of the battery to be tested.

[0023] In combination with the second aspect and some implementations of the second aspect, in other implementations of the second aspect, the AC power output from the output end of the active inverter module is output to the power grid after reactive power compensation.

[0024] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, the method also includes: the battery management system obtains a curve of the temperature change of the battery to be tested over time under a specific current, and determines the temperature of the battery to be tested at a third moment based on the curve of the temperature change of the battery to be tested over time under the specific current and the first current collected during the second time period, wherein the third moment is the last moment in the second time period.

[0025] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, the method further includes: the battery management system determines whether to issue an overtemperature alarm based on whether the temperature of the battery to be tested at the third moment is greater than a second threshold.

[0026] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, the battery management system obtains the OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested, including: obtaining the OCV-SOC curve and the SOC-charge curve of the battery to be tested at the temperature of the battery to be tested at a third moment.

[0027] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, the method further includes: the battery management system obtains a curve of the temperature change of the battery to be tested over time under a specific current, and determines the temperature of the battery to be tested at a fourth moment based on the curve of the temperature change of the battery to be tested over time under a specific current and the first current collected in the third time period, wherein the fourth moment is the last moment in the third time period; obtaining the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitor, including: obtaining the relationship between the SOH of the battery to be tested at the temperature and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitor based on the temperature of the battery to be tested at the fourth moment.

[0028] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, controlling the active inverter module to adjust the effective value of the voltage at the output end to the first voltage at the second moment includes: controlling the duty cycle of the switching tube in the active inverter module so that the effective value of the voltage at the output end is adjusted to the first voltage at the second moment.

[0029] In combination with the second aspect and certain implementations of the second aspect, in other implementations of the second aspect, the method further includes: when the first voltage is greater than a third threshold, the battery management system sets the first time interval to a second time interval, and the second time interval is greater than the first time interval.

[0030] In a third aspect, an electronic device is provided, comprising: a processor, wherein the processor is configured to test the power battery charger according to the testing method provided in the second aspect.

[0031] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed, the test method according to any one of the second aspects is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic diagram of a charger testing device provided in an embodiment of the present application.

[0033] FIG2 is a schematic diagram of a simulated load of a charger testing device provided in an embodiment of the present application.

[0034] FIG3 is a schematic diagram of an active inverter module of a charger testing device provided in an embodiment of the present application.

[0035] FIG4 is a flowchart of a charger testing method provided in an embodiment of the present application.

[0036] FIG5 is a flowchart of a charger testing method provided in another embodiment of the present application.

[0037] FIG6 is a flow chart of another charger testing method provided in the present application.

[0038] FIG7 is a schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The technical solution in this application will be described below with reference to the accompanying drawings.

[0040] The following describes the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " represents or. For example, A / B can represent A or B. "And / or" in this article is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two.

[0041] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0042] Lithium-ion batteries are widely used as power batteries due to their high energy density and low pollution levels. However, testing lithium-ion battery chargers places high demands on battery safety. Overheating, overcurrent, and overvoltage can damage the battery. Using a simulated battery can identify charger issues in advance, avoiding potential damage during real-world battery testing. However, the parameters of simulated batteries are limited and do not accurately reflect the performance of actual batteries.

[0043] Therefore, during the charger testing process, how to more accurately simulate the actual battery conditions becomes an urgent problem to be solved.

[0044] FIG1 is a schematic diagram of a charger testing device provided in an embodiment of the present application.

[0045] The present application provides a test device 120 for a charger that simulates the characteristics of a power battery. The device is applicable to scenarios such as the development, testing, and aging of a power battery charger 110. The device can simulate the characteristics of the battery to be tested and obtain close-to-real test results based on the actual characteristics of the battery to be tested. The device solves the problem that traditional power battery chargers need to use actual batteries during the development, testing, and aging stages, making it safer and more convenient.

[0046] The test device 120 may be the part in the wireframe in the figure, and may be referred to as the device 120 hereinafter. The test device 120 is provided with an input terminal 121 , and the charger 110 inputs electric energy to the test device 120 through the input terminal 121 ;

[0047] A simulated load 122 , wherein an access end of the simulated load 122 is connected to the input end 121 , and the simulated load 122 is used to simulate a charging load of a battery, serving as an external load of the charger 110 , to simulate battery charging;

[0048] An active inverter module 124 , wherein an input end of the active inverter module 124 is connected to an output end of the simulated load 122 , and an output end of the active inverter module 124 , i.e., an output end 125 of the test device 120 , is used to output alternating current;

[0049] The battery management system 123 (BMS) may include a setting module that includes input open-circuit voltage (OCV)-battery state of charge (SOC) corresponding curves, initial SOC, initial cell temperature, cell internal parameters, etc., and the function of setting battery parameters including preset conditions for abnormal conditions such as high and low cell temperatures, overvoltage and undervoltage. The BMS may also include a control module that can integrate the charging power according to the settings and update the SOC, cell voltage, and total battery voltage to achieve the purpose of simulating charging changes. It can also receive and decode CAN messages from the charger 110, encode battery status information, and send it to the charger 110 via CAN.

[0050] The test device 120 for the power battery charger 110 provided herein simulates the parameters of the battery under test and outputs electrical energy in a controllable manner. Because it eliminates the need for a battery's energy storage process, it can achieve fast charging and discharging. The test process is safe and does not damage the battery, ensuring the safety and efficiency of the charger 110 test.

[0051] The BMS 123 can obtain parameters such as the OCV-SOC curve, the SOC-charge curve, and the SOH of the battery to be tested, so that the testing device 120 can better simulate the parameters of the battery to be tested under different charging states.

[0052] The BMS 123 can also be used to calculate the state parameters of the battery under test based on the parameters, current, voltage, etc. of the battery under test.

[0053] The BMS 123 may also be used to sample the voltage and current of components in the test device 120 .

[0054] The BMS 123 may also be used to control the electrical components of the testing device 120 to perform various functions in the embodiments of the present application.

[0055] The BMS 123 can also be used to determine whether to issue an alarm based on the acquired data, such as overcurrent, overvoltage, overtemperature, etc.

[0056] The test device 120 may further include a display unit for displaying the total battery voltage, battery capacity, cell voltage, cell temperature, alarm status, and other status of the simulated battery in real time.

[0057] The output end of the test device 120 can be connected to the power grid. When connected to the power grid, a power converter, a reactive power compensation module, etc. can be set to meet the grid connection requirements.

[0058] The output end of the device 120 can also be connected to other loads to consume this part of the electrical energy, or can be connected to an energy storage device, which is not limited in this application.

[0059] The specific structure of the device 120 is described below with reference to FIG. 2-3 .

[0060] 2-3 are schematic diagrams of components of a charger testing device 120 provided in an embodiment of the present application.

[0061] As shown in Figure 2, simulated load 122 includes a first resistor, a second resistor, and a first capacitor, which respectively simulate the equivalent internal resistance, polarization resistance, and polarization capacitance of the power battery under test. The access terminal of simulated load 122 is connected to input terminal 121, wherein the second resistor and the first capacitor are connected in parallel, and the two ends of the parallel connection are respectively connected to one end of the first resistor and the output terminal of simulated load 122, and the other end of the first resistor is connected to the access terminal of simulated load 122.

[0062] The simulated load provided in this application simulates the parameters of the battery to be tested into circuit elements according to the Thevenin model, and can truly reflect the parameters of the battery.

[0063] As shown in FIG3 , which is a schematic diagram of the active inverter module 124 , the input end of the active inverter module 124 is connected to the output end of the simulated load 122 .

[0064] As a possible embodiment, as shown in FIG3(a), the active inverter module 124 may include a switch S1, a first diode, and a DC / AC module. The positive input of the active inverter module 124 is connected to the source of the first switch S1, the negative input is connected to the positive electrode of the diode and the negative input of the DC / AC module, and the drain of the switch S1 is connected to the negative electrode of the first diode and the positive input of the DC / AC module. The positive and negative outputs of the active inverter module 124 are connected to the DC / AC module.

[0065] As another possible embodiment, as shown in (b) of Figure 3, it differs from (a) of Figure 3 in that the DC / AC module may specifically include a switch tube S2, a switch tube S3, a switch tube S4, a switch tube S5, a second diode, a third diode, a fourth diode and a fifth diode. Among them, the drain of the switch tube S2 is connected to the anode of the second diode and to the positive output electrode of the active inverter module 124; the source of the switch tube S2 is connected to the cathode of the second diode and to the drain of the switch tube S1; the drain of the switch tube S3 is connected to the anode of the third diode and to the negative output electrode of the active inverter module 124; the source of the switch tube S3 is connected to the cathode of the third diode and to the drain of the switch tube S1; the drain of the switch tube S4 is connected to the anode of the fourth diode and to the negative input electrode of the active inverter module 124; the source of the switch tube S4 is connected to the cathode of the fourth diode and to the positive output electrode of the active inverter module 124; the drain of the switch tube S5 is connected to the anode of the fifth diode and to the negative input electrode of the active inverter module 124; and the source of the switch tube S5 is connected to the cathode of the fifth diode and to the negative output electrode of the active inverter module 124.

[0066] As a possible embodiment, the BMS 123 may control the duty cycle of the switch tube in the active inverter module 124 so as to adjust the effective value of the voltage at the output end to the first voltage at the second moment.

[0067] The active inverter module 124 provided in the present application can adjust the voltage and power output at the output end by changing the duty cycle of the switching tube, thereby simulating the effect of the battery showing different SOC states as the charging process progresses, which is closer to the actual battery situation and better simulates the current and voltage changes of the battery during the charging cycle, making the test results of the charger 110 more accurate.

[0068] It should be understood that the active inverter module in Figure 3 is only exemplary. The active inverter module 124 can also be a topology structure capable of three-phase inversion or a topology structure capable of multi-level inversion. These possible implementations should be regarded as possible embodiments of the present application.

[0069] Exemplarily, the switch tube may be a transistor, a thyristor, a field effect tube, a relay, or other switch that can be controlled by electricity.

[0070] FIG4 is a flowchart of a charger testing method provided in an embodiment of the present application.

[0071] As shown in Figure 4, the power battery charger test method, since the battery's SOC is constantly changing during the charging process, and the change in the battery's SOC state will cause the OCV to change, thereby causing the charging voltage to change. If the simulated battery parameters to be tested are single, the change in OCV will not be reflected. The method provided in this application can introduce the OCV parameters of the battery to be tested under different SOC states, which can better simulate the parameters of the battery to be tested in real conditions. This method can be executed by BMS123 or other separate devices, and the method includes:

[0072] 410 , obtaining an OCV-SOC curve and an SOC-charge curve of the battery to be tested.

[0073] The BMS 123 can read the data or manually input the OCV-SOC curve and SOC-charge curve of the battery to be tested into the BMS 123 through the setting module.

[0074] As a possible embodiment, the OCV-SOC curve and the SOC-charge curve of the battery to be tested may be actual experimental data of the battery to be tested, or may be empirical parameters, or may be estimated curves, which are not limited in this application.

[0075] 420 , integrating the first current in a first time period to obtain a charge of the battery to be tested.

[0076] The BMS 123 may sample the first current at the input terminal. It should be understood that the current is not constant during the charging process. In order to obtain an accurate accumulated charge, the first current at the input terminal may be continuously detected or periodically sampled.

[0077] The first current may be sampled by an ADC or detected by other instruments.

[0078] The first time period can be considered to be the time period from the start time to the first time point at which calculation begins. The first time point is the last time point in the first time period, for example, the last sampling cycle or the last second in the first time period. The charge accumulated in the battery under test can be obtained by integrating the first current in the first time period with respect to time.

[0079] As another possible embodiment, BMS 123 may also obtain a curve showing how the temperature of the battery under test changes over time at a specific current, and determine the temperature of the battery under test at a third moment based on the curve showing how the temperature of the battery under test changes over time at the specific current and the first current collected during the second time period. Based on the temperature of the battery under test at the third moment, an OCV-SOC curve and an SOC-charge curve of the battery under test at that temperature are obtained, where the third moment is the last moment in the second time period. Since the OCV-SOC curve and SOC-charge curve of the battery may change with temperature, the temperature change can be simulated to simulate a more realistic operating state of the battery under test.

[0080] In the embodiment provided in the present application, by obtaining a curve of the temperature change of the battery to be tested over time at a specific current, the temperature change of the battery to be tested during the charging process can be simulated, thereby introducing the temperature variable into the test process of the charger, and the test result is more accurate.

[0081] Specifically, by considering the effect of temperature on the OCV-SOC curve and the SOC-charge curve of the battery to be tested, the apparent parameters of the simulated battery to be tested are made consistent with the temperature changes during the charging process, thereby further improving the accuracy of the test results.

[0082] 430 , determining the SOC of the battery to be tested according to the charge of the battery to be tested and the SOC-charge curve.

[0083] The current SOC state of the battery to be tested can be determined based on the accumulated charge and the SOC-charge curve.

[0084] 440 , determining a first voltage according to the OCV-SOC curve and the SOC of the battery to be tested.

[0085] The BMS 123 may sample the second current at the access end of the active inverter module 124 at the first moment, determine the Uoc of the battery to be tested according to the SOC and the OCV-SOC curve of the battery to be tested, and determine the first voltage at the output end of the active inverter module 124 according to the Uoc, the resistance value of the first resistor, the resistance value of the second resistor, and the second current.

[0086] It should be understood that the open circuit voltage Uoc (ie OCV) of the battery to be tested can be the output terminal voltage U L , the voltage division of the equivalent internal resistance R0 and the equivalent polarization resistance R PThe sum of the divided voltages. Since direct current flows through the circuit, the voltage on the equivalent polarized capacitor is almost unchanged, so almost no current is generated on the equivalent polarized capacitor, and the current flowing through the equivalent polarized capacitor branch is almost 0, while the current in the equivalent polarized resistor branch is equal to the current of the main circuit. Therefore, the magnitude of the current flowing through the equivalent polarized resistor should be equal to the magnitude of the current flowing through the equivalent internal resistor and equal to the second current at the output end. Therefore, the first voltage at the output end of the battery to be tested can be determined based on Uoc, the resistance value of the equivalent internal resistor, the resistance value of the equivalent polarized resistor, and the second current.

[0087] 450 , controlling the active inverter module 124 to adjust the effective value of the voltage at the output end to the first voltage at the second moment.

[0088] Since the active inverter module 124 outputs AC power that has been inverted by the switching tube, the effective value of the voltage of the AC power can be adjusted by the duty cycle of the switching tube, so that the effective value of the voltage of the AC power is adjusted to the first voltage at the second moment, thereby better simulating the actual situation of the battery to be tested and completing the charger test more accurately.

[0089] When the first voltage is large, faster voltage changes may cause great stress to the circuit elements. For example, when the first voltage is greater than the third threshold, the adjustment time, that is, the first time interval, can be set to a second time interval, which is greater than the first time interval.

[0090] The current and voltage of the input terminal 121 at the second moment are sampled, and whether there is overcurrent is determined based on whether the current of the input terminal 121 is greater than the first threshold, and whether there is overvoltage or undervoltage is determined based on the relationship between the voltage of the input terminal 121 and the preset condition.

[0091] Based on the current and voltage at the input of the charger test device after adjusting the output voltage, a determination is made as to whether the current exceeds the tolerance range of the battery under test. The first threshold value may be actual experimental data of the battery under test, an empirical parameter, or an estimated value, which is not limited in this application. The preset condition may be that if the sampled voltage is greater than a preset threshold, it is determined to be overvoltage, and if the sampled voltage is less than the preset threshold, it is determined to be undervoltage.

[0092] In the embodiment provided in the present application, the charger test device can adjust the output voltage amplitude of the output end by connecting an active inverter module to the output end of the simulated load, and then match the open circuit voltage value according to the obtained OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested, so that the apparent parameters of the test device are closer to the actual battery situation, thereby achieving the purpose of more realistic simulation of the battery to be tested.

[0093] FIG5 is a flowchart of a charger testing method provided in another embodiment of the present application.

[0094] As shown in FIG5 , the charger test method is used. Since batteries will experience aging phenomena such as increased internal resistance, changes in polarization resistance and polarization capacitance, and reduced available capacity during use, and the charger is used to charge unspecified batteries, it should also meet the needs of batteries under various conditions. In order to simulate the battery aging process and more closely resemble the conditions faced by real chargers, the present application provides a charger test method. This method can be executed by BMS123 or other separate devices. The difference between this method and the embodiment in FIG4 is that this method can also include:

[0095] 510 , obtaining a correspondence between the state of health (SOH) of the battery to be tested and the equivalent internal resistance, polarization resistance, and polarization capacitance.

[0096] As a possible embodiment, the BMS 123 can read data or manually input the corresponding relationship between the SOH of the battery to be tested and the equivalent internal resistance, polarization resistance, and polarization capacitance into the BMS 123 through a setting module. The corresponding relationship between the SOH of the battery to be tested and the equivalent internal resistance, polarization resistance, and polarization capacitance can be actual experimental data of the battery to be tested, or it can be an empirical parameter, or it can be an estimated curve, which is not limited in this application.

[0097] As another possible embodiment, BMS123 can also obtain a curve of the temperature change of the battery to be tested over time at a specific current, and determine the temperature of the battery to be tested at a third moment based on the curve of the temperature change of the battery to be tested over time at a specific current and the first current collected in the second time period, and obtain the relationship between the SOH of the battery to be tested at the temperature and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitor of the battery to be tested at the third moment according to the temperature of the battery to be tested, wherein the fourth moment is the last moment in the third time period.

[0098] In the embodiment provided in the present application, by obtaining a curve of the temperature change of the battery to be tested over time at a specific current, the temperature change of the battery to be tested during the charging process can be simulated, thereby introducing the temperature variable into the test process of the charger, and the test result is more accurate.

[0099] Specifically, by considering the influence of temperature on the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitance of the battery to be tested, the apparent parameters of the simulated battery to be tested are made consistent with the temperature changes during the charging process, thereby further improving the accuracy of the test results.

[0100] 520 , adjusting the resistance value of the first resistor, the resistance value of the second resistor, and the capacitance value of the first capacitor of the simulated load 122 according to the corresponding relationship between the SOH of the battery to be tested and the equivalent internal resistance, polarization resistance, and polarization capacitance.

[0101] In this step, BMS123 may match the resistance value of the equivalent internal resistance, the resistance value of the polarization resistance, and the capacitance value of the polarization capacitor with the SOH of the battery to be tested through the resistance value of the first resistor, the resistance value of the second resistor, and the capacitance value of the first capacitor of the simulated load 122, so that the parameters of the simulated load 122 can fit the actual battery in use, thereby obtaining a more accurate test result.

[0102] In the embodiment provided in the present application, the testing device of the charger obtains the relationship between the SOH and the resistance value of the equivalent internal resistance of the battery to be tested, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitor, and then changes the battery simulation parameters in the simulated load according to the relationship, so that the testing device can simulate batteries to be tested with different degrees of aging, thereby achieving the purpose of more realistic simulation of the battery to be tested.

[0103] FIG6 is a flow chart of another charger testing method provided in the present application.

[0104] As shown in FIG6 , since the temperature of the battery during charging changes with charging time, and the battery under test may have different parameter characteristic curves at different temperatures, in order to simulate the parameters of the battery under test closer to the actual conditions, the parameter characteristic curves at different temperatures can be used to achieve this goal by simulating temperature changes. This method can be executed by the BMS 123 or by another separate device. The difference between this method and the embodiment in FIG4 is that the method can also include:

[0105] 610 , obtaining a curve of temperature variation of the battery to be tested over time at a specific current.

[0106] BMS123 can pre-acquire a curve showing how the temperature of the battery to be tested changes with the charging process. The curve can be a parameter obtained by charging the actual battery under different current conditions, and can be an empirical parameter or calculated data. This application does not limit this.

[0107] 620 , determine the temperature at a third moment according to a curve of a temperature change of the battery to be tested over time at a specific current and the first current.

[0108] When a curve of the temperature change of the battery to be tested over time at a specific current and the first current in the second time period have been obtained, the temperature of the battery to be tested at the third moment at the end of the second time period can be calculated. The calculation can be done by differentiation followed by integration or by an approximate algorithm, which is not limited in this application.

[0109] 630 , determining whether to issue an over-temperature alarm based on whether the temperature of the battery to be tested at the third moment is greater than a second threshold.

[0110] When the temperature of the simulated battery under test exceeds a preset upper limit, the BMS123 can also issue an over-temperature alarm and communicate with the charger via CAN. The charger can record this status and stop charging.

[0111] FIG7 is a schematic diagram of an electronic device provided in an embodiment of the present application.

[0112] As shown in FIG. 7 , the electronic device may include a processor 710 .

[0113] The processor 710 can be used to execute any one of the testing methods in the above embodiments.

[0114] The processor 710 mentioned in the embodiment of the present application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) neural network chips or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. It should be understood that the processor 710 and the memory 720 can be placed separately or integrated. When the processor is a neural network chip, the device may not include a memory.

[0115] In a possible embodiment, the electronic device may include a memory 720 , which may store the battery parameters in the above embodiments, such as an OCV-SOC curve, an SOC-charge curve, etc. It may also store other required data.

[0116] The processor 710 and the memory 720 can be coupled via a bus. The memory 720 is used to store computer program instructions or data. The processor 710 reads the computer instructions stored in the memory 720 or reads the data stored in the memory 720 to execute the test method in the above embodiment.

[0117] It should also be understood that the memory 720 mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0118] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0119] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by the processor 710, each step in the above method embodiment can be implemented.

[0120] It should be understood that the above-mentioned specific embodiments of the present application are exemplary, and those skilled in the art can implement them individually or combine the methods between the embodiments to implement them.

[0121] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A test device for a power battery charger, characterized in that: The test device is used to simulate a battery to be tested and to be charged, and the test device comprises: An input terminal (121), through which the charger (110) inputs electrical energy into the testing device; A simulated load (122), wherein an access end of the simulated load (122) is connected to the input end (121), the simulated load (122) comprises a first resistor, a second resistor and a first capacitor, and the simulated load (122) is used to simulate a charging load of a battery, wherein the second resistor and the first capacitor are connected in parallel, and both ends of the parallel connection are respectively connected to one end of the first resistor and the output end of the simulated load (122), and the other end of the first resistor is connected to the access end of the simulated load (122); An active inverter module (124), wherein the access end of the active inverter module (124) is connected to the output end of the simulated load (122), and the output end of the active inverter module (124) is used to output alternating current; A battery management system (123), the battery management system (123) being used to obtain an open circuit voltage (OCV)-battery state of charge (SOC) curve of the battery to be tested and an SOC-charge amount curve of the battery to be tested; Sampling a first current at the input end, and integrating the first current within a first time period to obtain a charge amount of the battery to be tested; Determining the SOC of the battery to be tested according to the charge of the battery to be tested and the SOC-charge curve; The second current of the access terminal of the active inverter module (124) is sampled at a first moment, and the U of the battery to be tested is determined according to the SOC of the battery to be tested and the OCV-SOC curve. oc , and according to the U oc , the resistance value of the first resistor, the resistance value of the second resistor, and the second current determine a first voltage at an output end of the active inverter module (124), wherein the first moment is the last moment of the first time period; Controlling the active inverter module (124) to adjust the effective value of the voltage at the output end to the first voltage at a second moment, wherein the second moment lags behind the first moment by a first time interval; The current and voltage of the input terminal (121) at the second moment are sampled, and whether there is overcurrent is determined based on whether the current of the input terminal (121) is greater than a first threshold value, and whether there is overvoltage or undervoltage is determined based on the relationship between the voltage of the input terminal (121) and a preset condition.

2. The testing device according to claim 1, characterized in that: The battery management system (123) is further used to obtain the relationship between the battery health SOH of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitance of the battery to be tested, and determine the resistance value of the first resistor, the resistance value of the second resistor and the capacitance value of the first capacitor according to the expected SOH of the battery to be tested, The resistance value of the first resistor is the equivalent internal resistance of the battery to be tested, the resistance value of the second resistor is the equivalent polarization resistance of the battery to be tested, and the capacitance value of the first capacitor is the equivalent polarization capacitance of the battery to be tested.

3. The testing device according to claim 1 or 2, characterized in that: The alternating current output from the output end of the active inverter module (124) is output to the power grid after reactive power compensation.

4. The testing device according to claim 1 or 2, characterized in that: The battery management system (123) is also used for: A curve of the temperature of the battery to be tested changing with time under a specific current is obtained, and the temperature of the battery to be tested at a third moment is determined according to the curve of the temperature of the battery to be tested changing with time under the specific current and the first current collected in a second time period, wherein the third moment is the last moment in the second time period.

5. The testing device according to claim 4, characterized in that: The battery management system (123) is also used for: Whether to issue an over-temperature alarm is determined according to whether the temperature of the battery to be tested at the third moment is greater than a second threshold.

6. The testing device according to claim 4, characterized in that: The obtaining of the OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested includes: According to the temperature of the battery to be tested at the third moment, an OCV-SOC curve of the battery to be tested and a SOC-charge curve of the battery to be tested at the temperature are obtained.

7. The testing device according to claim 2, characterized in that: The battery management system (123) is also used for: Obtaining a curve of a temperature change of the battery to be tested over time under a specific current, and determining the temperature of the battery to be tested at a fourth moment according to the curve of a temperature change of the battery to be tested over time under the specific current and the first current collected in a third time period, wherein the fourth moment is the last moment in the third time period; The step of obtaining the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitance of the battery to be tested includes: According to the temperature of the battery to be tested at the fourth moment, the relationship between the SOH of the battery to be tested at the temperature and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitance of the battery to be tested is obtained.

8. The testing device according to claim 1 or 2, characterized in that: The controlling the active inverter module (124) to adjust the effective value of the voltage at the output end to the first voltage at the second moment comprises: The duty cycle of the switch tube in the active inverter module (124) is controlled so that the effective value of the voltage at the output end is adjusted to the first voltage at the second moment.

9. The testing device according to claim 1 or 2, characterized in that: The battery management system (123) is also used for: When the first voltage is greater than a third threshold, the first time interval is set to a second time interval, and the second time interval is greater than the first time interval.

10. A method for testing a power battery charger, characterized in that: The test method is applied to a test device for a power battery charger, wherein the test device comprises: An input end (121), a simulated load (122), an access end of the simulated load (122) being connected to the input end (121), the simulated load (122) comprising a first resistor, a second resistor and a first capacitor, the simulated load (122) being used to simulate a charging load of a battery, wherein the second resistor and the first capacitor are connected in parallel, and the two ends after the parallel connection are respectively connected to one end of the first resistor and the output end of the simulated load (122), and the other end of the first resistor is connected to the access end of the simulated load (122), wherein the charger inputs electric energy to the test device through the input end (121); an active inverter module (124), the access end of the active inverter module (124) being connected to the output end of the simulated load (122); and a battery management system (123); The test method includes: The battery management system (123) obtains an OCV-SOC curve of the battery to be tested and an SOC-charge curve of the battery to be tested; sampling a first current at an input terminal (121) of a test device, and integrating the first current within a first time period to obtain a charge amount of the battery to be tested; Determining the SOC of the battery to be tested according to the charge of the battery to be tested and the SOC-charge curve; The second current of the access terminal of the active inverter module (124) is sampled at a first moment, and the U of the battery to be tested is determined according to the SOC of the battery to be tested and the OCV-SOC curve. oc , and according to the U oc , the resistance value of the first resistor, the resistance value of the second resistor, and the second current determine a first voltage at the output end of the active inverter module (124), wherein the first moment is the last moment of the first time period, the resistance value of the first resistor is the resistance value of the equivalent internal resistance of the battery to be tested, and the resistance value of the second resistor is the resistance value of the equivalent polarization resistance of the battery to be tested; Controlling the active inverter module (124) to adjust the effective value of the voltage at the output end to the first voltage at a second moment, wherein the second moment lags behind the first moment by a first time interval; The current and voltage of the input terminal (121) at the second moment are sampled, and whether there is overcurrent is determined based on whether the current of the input terminal (121) is greater than a first threshold value, and whether there is overvoltage or undervoltage is determined based on the relationship between the voltage of the input terminal (121) and a preset condition.

11. The testing method according to claim 10, characterized in that: The method further comprises: The battery management system (123) obtains the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance and the capacitance value of the equivalent polarization capacitance of the battery to be tested, and determines the resistance value of the first resistor, the resistance value of the second resistor and the capacitance value of the first capacitor according to the expected SOH of the battery to be tested, The capacitance value of the first capacitor is the capacitance value of the equivalent polarization capacitance of the battery to be tested.

12. The testing method according to claim 10 or 11, characterized in that: The alternating current output from the output end of the active inverter module (124) is output to the power grid after reactive power compensation.

13. The testing method according to claim 10 or 11, characterized in that: The method further comprises: The battery management system (123) obtains a curve of the temperature of the battery to be tested changing with time under a specific current, and determines the temperature of the battery to be tested at a third moment according to the curve of the temperature of the battery to be tested changing with time under the specific current and the first current collected in a second time period, wherein the third moment is the last moment in the second time period.

14. The testing method according to claim 13, characterized in that: The method further comprises: The battery management system (123) determines whether to issue an over-temperature alarm according to whether the temperature of the battery to be tested at a third moment is greater than a second threshold.

15. The testing method according to claim 13, characterized in that: The battery management system (123) obtains the OCV-SOC curve of the battery to be tested and the SOC-charge curve of the battery to be tested, including: According to the temperature of the battery to be tested at the third moment, an OCV-SOC curve of the battery to be tested and a SOC-charge curve of the battery to be tested at the temperature are obtained.

16. The testing method according to claim 11, characterized in that: The method further comprises: The battery management system (123) obtains a curve of the temperature of the battery to be tested changing with time under a specific current, and determines the temperature of the battery to be tested at a fourth moment according to the curve of the temperature of the battery to be tested changing with time under the specific current and the first current collected in a third time period, wherein the fourth moment is the last moment in the third time period; The step of obtaining the relationship between the SOH of the battery to be tested and the resistance value of the equivalent internal resistance, the resistance value of the equivalent polarization resistance, and the capacitance value of the equivalent polarization capacitance of the battery to be tested includes: According to the temperature of the battery to be tested at the fourth moment, the SOH of the battery to be tested at the temperature and the The relationship between the resistance of the equivalent internal resistance, the resistance of the equivalent polarization resistance and the capacitance of the equivalent polarization capacitance of the battery to be tested.

17. The testing method according to claim 10 or 11, characterized in that: The controlling the active inverter module (124) to adjust the effective value of the voltage at the output end to the first voltage at the second moment comprises: The duty cycle of the switch tube in the active inverter module (124) is controlled so that the effective value of the voltage at the output end is adjusted to the first voltage at the second moment.

18. The testing method according to claim 10 or 11, characterized in that: The method further comprises: When the first voltage is greater than a third threshold, the battery management system (123) sets the first time interval to a second time interval, and the second time interval is greater than the first time interval.

19. An electronic device, characterized in that: The electronic device comprises: processor, The processor is used to test the power battery charger according to the testing method according to any one of claims 10 to 18.

20. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the testing method according to any one of claims 10 to 18 is implemented.

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