Charge state estimation system and information processing method thereof

Abstract

The invention provides a state-of-charge estimation system and an information processing method thereof, the state-of-charge estimation system comprises a charge and discharge tester and an environment bin, and the method comprises the following steps: controlling the environment bin to provide a corresponding test environment for a power battery, and controlling the charge and discharge tester to charge or discharge according to charge and discharge parameters corresponding to the power battery; a plurality of battery parameters of the power battery are collected in real time in the charging or discharging process, and the reference charge state of the power battery is determined through the charging and discharging tester; according to the plurality of battery parameters of the power battery, calculating corresponding estimated charge states of the power battery under a plurality of preset calculation strategies; and according to the estimated charge state and the reference charge state corresponding to each preset calculation strategy, determining the estimation precision of the power battery under each preset calculation strategy when the power battery is charged or discharged under the test environment and the charge and discharge parameters.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to a state of charge estimation system and an information processing method thereof. Background Art

[0002] With the rapid development of electric vehicles, the power batteries used in them are key components. Their performance testing and evaluation are crucial for ensuring the overall power and safety performance of electric vehicles. A power battery's State of Charge (SOC) is a crucial indicator for measuring the remaining charge in the battery. Accurately estimating the SOC of a power battery is crucial for improving the safety, reliability, and range of electric vehicles. Currently, commonly used power battery SOC estimation methods suffer from errors in practical applications, impacting the accuracy of SOC estimation for power battery evaluations. Summary of the Invention

[0003] In view of this, the purpose of the present application is to at least provide a state of charge estimation system and an information processing method thereof, by placing a power battery in an environmental chamber to provide a test environment for the power battery, and connecting the power battery through a charge and discharge tester to charge and discharge the power battery, and then collecting various battery parameters of the power battery during the charging and discharging process, and determining the reference state of charge of the power battery through the charge and discharge tester, and calculating the estimated state of charge according to a plurality of preset calculation strategies, so as to determine the estimation accuracy by using the reference state of charge and the estimated state of charge, and facilitate selecting the best estimation method for state of charge estimation, thereby solving the technical problem of inaccurate state of charge estimation in the prior art and achieving the technical effect of increasing the estimation accuracy of the state of charge.

[0004] This application mainly includes the following aspects: In a first aspect, an embodiment of the present application provides an information processing method for a state of charge estimation system, wherein the state of charge estimation system includes a charge and discharge tester and an environmental chamber, the power battery is placed inside the environmental chamber, and the charge and discharge tester is connected to the power battery to charge or discharge the power battery, wherein the method includes: controlling the environmental chamber to provide the power battery with its corresponding test environment, and controlling the charge and discharge tester to charge or discharge according to the charge and discharge parameters corresponding to the power battery; collecting multiple battery parameters of the power battery in real time during the charging or discharging process, and determining the reference state of charge of the power battery through the charge and discharge tester; calculating the estimated state of charge corresponding to the power battery under multiple preset calculation strategies through the multiple battery parameters of the power battery; and determining the estimation accuracy of the power battery under each preset calculation strategy when charging or discharging in the test environment and the charge and discharge parameters according to the estimated state of charge and the reference state of charge corresponding to each preset calculation strategy.

[0005] Optionally, the reference state of charge refers to the state of charge of the power battery at the end of charging or discharging, wherein the reference state of charge is determined in the following manner: at the end of charging or discharging, a first state of charge change of the power battery is determined by the charge and discharge tester, where the first state of charge change refers to the state of charge charged into the power battery during the charging process or the state of charge released from the power battery during the discharging process; and according to the initial state of charge of the power battery and the first state of charge change, the reference state of charge of the power battery at the end of charging or discharging is determined.

[0006] Optionally, the estimated state of charge refers to the estimated state of charge at the end of charging or discharging, and the estimated state of charge is determined in the following manner: for each preset calculation strategy, determine the preset battery parameters corresponding to the preset calculation strategy from multiple battery parameters, and calculate the estimated state of charge of the power battery at the end of charging or discharging through the preset calculation strategy and the preset battery parameters.

[0007] Optionally, the power battery includes a battery management system, which determines the initial state of charge in the following manner: receiving a starting state of charge reported by the battery management system at the beginning of charging or discharging, and receiving an ending state of charge reported by the battery management system at the end of charging or discharging; determining a second state of charge change detected by the battery management system during the charging or discharging stage based on the ending state of charge and the starting state of charge; determining a system error of the battery management system based on the first state of charge change and the second state of charge change; and calculating the initial state of charge through the starting state of charge and the system error.

[0008] Optionally, the power battery is used in a vehicle, and the method further includes: connecting the low-voltage interface of the power battery to a low-voltage constant-voltage source, and controlling the low-voltage constant-voltage source to transmit electrical energy to the low-voltage interface; connecting the key door interface of the power battery to a first analog output interface, and controlling the first analog output interface to send a key door signal to the key door interface to wake up the power battery; before charging the power battery, connecting the charging gun interface of the power battery to a second analog output interface, and controlling the second analog output interface to send a charging gun connection signal to the charging gun interface to inform the power battery to be charged through the charging gun.

[0009] Optionally, the power battery includes a battery management system, which is used to report multiple battery parameters; and / or the multiple preset calculation strategies include an ampere-hour integration method and an open circuit voltage method.

[0010] Optionally, the method further includes: determining a fault type of the power battery through a fault signal reported by the battery management system, and performing corresponding processing according to the fault type.

[0011] Optionally, the power battery includes at least one, and each power battery has at least one different battery specification, wherein the battery specification includes battery type, usage level and battery specification.

[0012] In a second aspect, an embodiment of the present application further provides a state of charge estimation system, the system comprising: a power battery; an environmental chamber, for providing the power battery with its corresponding test environment, the power battery being placed inside the environmental chamber; a charge and discharge tester, the charge and discharge tester being connected to the power battery to charge or discharge the power battery; and a processor, the processor being respectively connected to the power battery, the environmental chamber and the charge and discharge tester, for executing the steps of the method described in the first aspect or any possible implementation manner of the first aspect.

[0013] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation of the first aspect are executed.

[0014] An embodiment of the present application provides a state of charge estimation system and information processing method thereof. The state of charge estimation system includes a charge-discharge tester and an environmental chamber, wherein the power battery is placed inside the environmental chamber, and the charge-discharge tester is connected to the power battery to charge or discharge the power battery. The method includes: controlling the environmental chamber to provide the power battery with its corresponding test environment, and controlling the charge-discharge tester to charge or discharge according to the charge and discharge parameters corresponding to the power battery; collecting multiple battery parameters of the power battery in real time during the charging or discharging process, and determining the reference state of charge of the power battery through the charge and discharge tester; calculating the estimated state of charge corresponding to the power battery under multiple preset calculation strategies based on the multiple battery parameters of the power battery; and determining the estimation accuracy of the power battery under the preset calculation strategies according to the estimated state of charge and the reference state of charge corresponding to each preset calculation strategy. This method solves the technical problem of inaccurate state of charge estimation in the prior art and achieves the technical effect of increasing the accuracy of state of charge estimation.

[0015] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A flowchart of an information processing method of a state of charge estimation system provided in an embodiment of the present application is shown.

[0018] Figure 2 A structural diagram of a state of charge estimation system provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of illustration and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps without logical context can be reversed or implemented simultaneously. In addition, those skilled in the art, under the guidance of the contents of this application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0020] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0021] In the existing technology, power batteries are key core components of new energy vehicles, and their performance testing and evaluation are important links to ensure the power performance and safety performance of electric vehicles. The state of charge of a power battery is an important indicator to measure the remaining battery power. Accurately estimating the state of charge of a power battery is of great significance to improving the range, safety and reliability of electric vehicles. As the battery ages, its internal resistance increases, which will generate more heat and be more likely to cause thermal runaway. The battery state of charge is the basis for estimating the range of electric vehicles. It is also an important parameter to assist in correcting and improving the estimation accuracy of the battery state of charge, and it is also the basis for predictive maintenance. However, the degradation patterns of different batteries are inconsistent, making it difficult to determine the accuracy of the state of charge estimation of different batteries.

[0022] Based on this, an embodiment of the present application provides a state of charge estimation system and an information processing method thereof, which places a power battery in an environmental chamber to provide a test environment for the power battery, connects the power battery through a charge and discharge tester to charge and discharge the power battery, and then collects various battery parameters of the power battery during the charge and discharge process, and determines the reference state of charge of the power battery through the charge and discharge tester. The estimated state of charge is calculated according to multiple preset calculation strategies, and the estimation accuracy is determined by using the reference state of charge and the estimated state of charge, so as to facilitate the selection of the best estimation method for state of charge estimation. In this way, the technical problem of inaccurate state of charge estimation in the prior art is solved, and the technical effect of increasing the accuracy of state of charge estimation is achieved, which is specifically as follows: See also Figure 1 , Figure 1 This is a flow chart of an information processing method for a state of charge estimation system provided in an embodiment of the present application. Figure 1 As shown, the information processing method of the state of charge estimation system provided in the embodiment of the present application includes the following steps: S101: Control the environmental chamber to provide the power battery with a corresponding test environment, and control the charge and discharge tester to charge or discharge according to the charge and discharge parameters corresponding to the power battery.

[0023] The state of charge estimation system includes a charge and discharge tester and an environmental chamber. The power battery is placed inside the environmental chamber. The charge and discharge tester is connected to the power battery to charge or discharge the power battery.

[0024] That is to say, the power battery for which the state of charge is to be estimated is placed inside the environmental chamber, the charge and discharge tester is controlled to charge or discharge the power battery, and the environmental chamber is controlled to provide the power battery with the test environment corresponding to the power battery, so that the power battery is charged or discharged under the test environment.

[0025] For example, a power battery is used in a vehicle, and the charge-discharge tester is used to simulate the charging or discharging process of the power battery installed in the vehicle. Furthermore, during the charging process, the charge-discharge tester simulates the charging process of the power battery on the vehicle, and during the discharging process, the charge-discharge tester simulates the discharging process of the power battery on the vehicle, thereby causing the charge state of the power battery to change during the charging or discharging process.

[0026] The method also includes: connecting the low-voltage interface of the power battery to a low-voltage constant-voltage source, and controlling the low-voltage constant-voltage source to transmit electrical energy to the low-voltage interface; connecting the key door interface of the power battery to a first analog output interface, and controlling the first analog output interface to send a key door signal to the key door interface to wake up the power battery; before charging the power battery, connecting the charging gun interface of the power battery to a second analog output interface, and controlling the second analog output interface to send a charging gun connection signal to the charging gun interface to inform the power battery to be charged through the charging gun.

[0027] The low-voltage constant-voltage source can be understood as the 12V power supply that the power battery needs to be connected to when used in a vehicle. The key-door signal transmitted by the first analog output interface is used to inform the vehicle in which the power battery is located whether it is unlocked. In other words, before the power battery can be charged or discharged, it is necessary to confirm that the low-voltage interface of the power battery is receiving power provided by the low-voltage constant-voltage source, and it is also necessary to confirm that the key-door interface of the power battery is receiving the key-door signal indicating that the vehicle is unlocked. In this way, when it is confirmed that the power battery is receiving 12V power from the low-voltage constant-voltage source and the vehicle is unlocked, the power battery wakes up and charging or discharging operations can be performed on the power battery.

[0028] The charging gun connection signal transmitted by the second analog output interface is used to describe whether the simulated charging gun is connected to the vehicle where the power battery is located. In other words, the SOC estimation system does not require the power battery to be placed on the vehicle, nor does it physically connect the charging gun to the vehicle. Instead, it uses the charging gun connection signal to simulate the connection status between the charging gun and the vehicle where the power battery is located. Furthermore, the power battery uses the charging gun connection signal transmitted by the second analog output interface to determine whether to charge the power battery.

[0029] Therefore, the first analog output interface and the second analog output interface are both used to simulate the signals received when the power battery is installed in a vehicle and used, so as to improve the authenticity of the state of charge estimation of the power battery in the state of charge estimation system.

[0030] Specifically, the power battery includes at least one, and each power battery has at least one different battery specification, where the battery specification includes battery type, usage level, and battery specification. That is, when selecting a power battery, multiple different test environments can be set for the power battery to determine the estimation accuracy of each preset estimation strategy under different test environments.

[0031] For example, in order to evaluate the applicability of the preset estimation strategy for different power batteries, and to determine the extent of the influence of the preset estimation strategy on the estimated state of charge of different power batteries, multiple power batteries are needed to study the influence of battery type, battery capacity and usage level on the accuracy of the estimated state of charge.

[0032] Battery types refer to common power battery types currently on the market, including ternary lithium batteries, lithium iron phosphate batteries, and lithium cobalt oxide batteries. These common battery types should be selected whenever possible to ensure broadly representative test results. In addition to common types, batteries with specialized chemistries, such as lithium titanate batteries, can also be considered. These batteries may differ from common types in certain performance aspects, which helps provide a more comprehensive understanding of the impact of different battery chemistries on the accuracy of state-of-charge estimation.

[0033] Among them, the degree of use is used to describe the degree of aging of the power battery. Furthermore, multiple power batteries can be selected from unused new batteries and old batteries of different service years. The accuracy of the estimated state of charge of new batteries can be understood through new batteries. The influence of old batteries of different service years on the accuracy of the estimated state of charge can be studied through old batteries of different service years. Old batteries can be obtained from electric vehicles, energy storage systems, etc. that have been used for a certain period of time, or can also be selected according to different numbers of charge and discharge cycles. Old batteries of different service years can also be selected for different application scenarios, such as selecting power batteries in vehicles used in high temperature areas, low temperature areas, or high humidity areas, so as to have a deeper understanding of the influence of service age and use environment on the accuracy of estimated state of charge.

[0034] Among them, battery specifications include battery capacity, and battery capacity can be set within a battery capacity range based on different application scenarios of power batteries. For example, electric vehicles generally require larger-capacity batteries, while some small electronic devices may use smaller-capacity batteries. When selecting test samples, these different capacity ranges should be covered to meet the testing requirements of different application scenarios. And within the determined battery capacity range, try to control the battery capacity of multiple power batteries to be evenly distributed. For example, if the battery capacity range is 20Ah (ampere-hour) to 100Ah, power batteries with battery capacities of 20Ah, 40Ah, 60Ah, 80Ah and 100Ah can be selected to more comprehensively understand the accuracy of the estimated state of charge of batteries with different capacities.

[0035] For example, the battery specifications may also include the battery manufacturer. For the same battery type, usage level, and battery capacity, the accuracy of the estimated state of charge (SOC) can be compared between different battery manufacturers. This facilitates understanding the accuracy of SOC estimation across different battery manufacturers.

[0036] For example, power batteries can be obtained from battery manufacturers, recycling markets, and laboratory inventories. Battery manufacturers can typically provide newly produced batteries as well as batteries that have undergone specific testing or use. The recycling market can identify batteries from different application scenarios, with varying usage histories and aging levels, providing a rich sample resource for testing. The performance and condition of power batteries in laboratory inventories may have been accurately recorded and evaluated, helping to increase test accuracy and improve test efficiency.

[0037] Specifically, after selecting the power battery, it is necessary to perform performance tests on the power battery, including capacity tests, internal resistance tests, open circuit voltage tests, etc. Furthermore, the power battery should be a usable battery determined through performance testing to eliminate faulty batteries, abnormal batteries, diving batteries, and batteries that have reached the end of their service life. Therefore, performance testing can screen out battery samples that meet the test requirements and understand the initial state of each sample, providing basic data for subsequent tests. In addition, the power battery needs to be marked to record information such as the battery type, battery capacity, age, and source of the power battery. During the testing process, it is necessary to ensure that the test data of each power battery is accurately recorded and tracked to facilitate data analysis and result evaluation.

[0038] Specifically, the test environment and charge and discharge parameters of the power battery are determined based on the battery type, battery capacity and usage level of the power battery. Among them, the environmental parameters of the test environment should be selected from environmental parameters that will affect the battery parameters such as temperature and voltage of the power battery during charging or discharging. For example, the environmental parameters include test temperature and / or test humidity. Different temperatures and humidities will affect the battery parameters during the charging and discharging process, and further affect the estimated state of charge. Furthermore, according to the conventional application scenarios and / or extreme scenarios of the power battery during the actual charging or discharging process, the test temperature and / or test humidity of the environmental chamber are selected, and the selected test temperature and / or test humidity are used as the environmental chamber to provide the power battery with its corresponding test environment. The test temperature can be a fixed temperature value, a temperature curve that changes with time, or a temperature range. The test temperature at each time is randomly selected within the temperature range. The test humidity can be set in the same way, which will not be repeated here.

[0039] Exemplary charge and discharge parameters include the number of charge and discharge cycles, the charge or discharge voltage, charge or discharge current, and charge or discharge power provided by the charge and discharge tester at various times during the charge and discharge process. The test environment and charge and discharge parameters must be limited to ensure that the power battery does not fail during the charge or discharge process. In other words, the power battery does not experience any phenomena such as voltage drop during the charge or discharge process that affect normal use of the power battery. Furthermore, the power battery's cutoff parameters are designed based on the actual charging and discharging conditions of the power battery during the charging or discharging process, indicating the corresponding markers for the start and end of charging or discharging, respectively. For example, if the power battery is used in a taxi and different drivers are used to drive the taxi, resulting in the taxi being used continuously, the power battery may end charging at a state of charge of 80% and begin charging at a state of charge of 30%. Furthermore, the power battery's charging start marker can be recorded as the total battery voltage corresponding to a state of charge of 30%, the charging end marker as the total battery voltage corresponding to a state of charge of 80%, the discharging start marker as the total battery voltage corresponding to a state of charge of 80%, and the discharging end marker as the total battery voltage corresponding to a state of charge of 30%. The charging or discharging voltage, current, power, etc. depend on the charging and discharging method and rate required for the power battery. For example, the charging and discharging method can be a constant current charging and discharging method, and the charging rate can be set based on the rate actually used when the power battery is charged. Different charging methods, such as fast charging and full charging, correspond to different rates. Therefore, according to different charging and discharging operating scenarios, the test environment and charging and discharging parameters are established by analyzing the changing characteristics, changing timing, and correlation between parameters of each parameter. In addition, the test environment and charging and discharging parameters can also be set accordingly based on the actual application scenarios of the power battery. This application does not limit the specific settings of the test environment and charging and discharging parameters.

[0040] Before executing step S101, the charge and discharge tester and the environmental chamber need to be calibrated. By calibrating the charge and discharge tester, the accuracy of the charging current and voltage output when the power battery is charged can be ensured, and the accuracy of the discharge current and voltage received when the power battery is discharged can also be ensured. Generally, standard ammeters, voltmeters and other equipment can be used for calibration. To calibrate the environmental chamber, it is necessary to calibrate the temperature of its temperature regulating device to be consistent with the temperature displayed on its temperature display to ensure the accuracy of its temperature control. A standard thermometer can be used for calibration. The processor also needs to be calibrated to ensure that it does not cause distortion of multiple battery parameters reported by the power battery to ensure that the collected data is accurate and reliable. Standard signal sources, thermometers and other equipment can be used for calibration.

[0041] Furthermore, the selected power batteries need to be inspected to ensure that there is no damage to the appearance, no leakage and other problems. They can be screened through visual inspection and simple electrical tests. If the power battery needs to be charged, the power battery can be discharged to the starting state of charging. If the power battery needs to be discharged, it needs to be charged to the starting state of discharge first. The charging and discharging method can be the same as or different from the subsequent charging and discharging method of the power battery. The type and specifications of the power battery need to be considered to ensure that the process is safe and reliable. Detailed test steps are formulated according to the determined test environment, including equipment connection, parameter setting, data acquisition, etc., to ensure that the test steps are clear and operational to improve test efficiency and accuracy.

[0042] For example, before the power battery is placed in the environmental chamber, it is necessary to adjust the environmental chamber to stabilize the test environment. You can also set up necessary safety measures, such as fire prevention equipment, ventilation equipment, etc., to ensure the safety of the test process. If there is strong electromagnetic interference in the test environment, electromagnetic shielding measures should be taken to ensure the accuracy of the test data. Then, after determining the test environment, charge and discharge parameters, and adjusting the environmental chamber to the test environment, the power battery can be placed in the environmental chamber, and the power battery can be charged or discharged according to the charge and discharge parameters using a charge and discharge tester.

[0043] S102: collecting multiple battery parameters of the power battery in real time during the charging or discharging process, and determining a reference state of charge of the power battery by using the charge and discharge tester.

[0044] Furthermore, multiple battery parameters reported by the power battery are received in real time during the charging or discharging process. In addition, data such as the charging current provided by the charge and discharge tester to the power battery during the charging process can be collected in real time, and data such as the discharge current released by the power battery during the discharging process can be received.

[0045] The power battery is a complete battery pack, consisting of multiple single cells and a battery management system (BMS). The multiple cells are connected in pre-designed series and parallel configurations. The BMS collects and reports multiple battery parameters at various moments during the full charge or discharge process. These parameters include battery temperature, single cell voltage, total battery voltage, and battery current (current during charging or discharging).

[0046] For example, see Figure 2 , Figure 2 This is a schematic diagram of the structure of a state of charge estimation system provided in an embodiment of the present application. Figure 2As shown, while the battery management system reports battery parameters in real time during charging and discharging, it will also report sampling fault signals when the sampled battery parameters are abnormal. The acquisition fault signals include various temperature fault signals involved in battery temperature acquisition, such as temperature sampling line open circuit fault, temperature sampling line short circuit to ground fault, temperature sampling line short circuit to power supply fault, temperature sampling line loose connection fault, and temperature sensor fault itself. The acquisition fault signals also include various cell voltage fault signals involved in cell voltage acquisition, such as cell voltage sampling line open circuit fault, cell voltage sampling line short circuit to ground fault, cell voltage sampling line short circuit to power supply fault, cell voltage sampling line loose connection fault, and cell voltage sensor fault itself. The acquisition fault signals also include various current fault signals involved in current acquisition, such as current sensor open circuit, short circuit, and other faults.

[0047] Specifically, the method further includes: determining the fault type of the power battery through the fault signal reported by the battery management system, and performing corresponding processing according to the fault type.

[0048] That is to say, based on the various fault signals reported by the battery management system, the current fault type of the power battery can be determined. In this way, the staff can handle it according to the corresponding processing method of the fault type to prevent testing under fault conditions, which will affect the safety and accuracy of the test.

[0049] For example, Figure 2As shown, the battery management system also needs to report multiple status signals in real time during the charging and discharging process. These signals include communication signals, low-voltage constant voltage source signals, key gate signals, charging gun connection signals, and high-voltage contactor status signals. The communication signals describe the status of the power battery's communication line, primarily reflecting normal communication, disconnected, shorted, shorted to power, and shorted to ground. The low-voltage constant voltage source signal is used to determine whether the power battery is connected to the low-voltage constant voltage source during the charging and discharging process. If the low-voltage constant voltage source signal indicates insufficient voltage or disconnection, the power battery stops operating. The key gate signal is used to determine whether the power battery is continuously in a simulated vehicle with the ignition on. If the key gate signal indicates that the vehicle key has been removed, the power battery stops operating. The charging gun connection signal is used to determine whether the power battery is connected to a simulated charging gun. If the charging gun connection signal indicates that the simulated charging gun has been removed from the vehicle during charging, the power battery stops operating. The high-voltage contactor, installed on the power battery's high-voltage bus, reports whether the bus is functioning properly. The high-voltage contactor status signals include contactor contact status, coil status, and fault status. Furthermore, before the power battery is placed in the environmental chamber for SOC estimation, it is necessary to provide the power battery with the signals required during use, based on actual vehicle conditions. This fully simulates the power battery's application scenarios, reduces errors between experiments and actual applications, and avoids inaccurate SOC estimates.

[0050] Specifically, the reference state of charge refers to the state of charge of the power battery at the end of charging or discharging, wherein the reference state of charge is determined in the following manner: at the end of charging or discharging, a first state of charge change of the power battery is determined by the charge and discharge tester, where the first state of charge change refers to the state of charge charged into the power battery during the charging process or the state of charge released from the power battery during the discharging process; and according to the initial state of charge of the power battery and the first state of charge change, the reference state of charge of the power battery at the end of charging or discharging is determined.

[0051] Because the state of charge estimated according to various preset calculation strategies may have errors, a charge-discharge tester is used to determine the change in the power battery's state of charge due to charging or discharging. Furthermore, based on the initial state of charge, combined with the state of charge charged into the power battery during charging or the state of charge released from the power battery during discharging, the reference state of charge of the power battery at the end of charging or discharging is determined.

[0052] That is, the initial state of charge of the power battery and the change in the first state of charge charged into the power battery by the charge-discharge tester are summed, and the sum is determined as the reference state of charge of the power battery at the end of charging. The initial state of charge of the power battery and the change in the first state of charge released by the charge-discharge tester during the discharge process are subtracted, and the difference is determined as the reference state of charge of the power battery at the end of discharge.

[0053] In one embodiment, the initial state of charge may be determined by collecting the battery voltage of the power battery, or may be the state of charge reported by a battery management system at the beginning of charging or discharging of the power battery.

[0054] In another embodiment, the initial state of charge is determined in the following manner: receiving a starting state of charge reported by the battery management system at the beginning of charging or discharging, and receiving an ending state of charge reported by the battery management system at the end of charging or discharging; determining a second state of charge change detected by the battery management system during the charging or discharging stage based on the ending state of charge and the starting state of charge; determining a system error of the battery management system based on the first state of charge change and the second state of charge change; and calculating the initial state of charge through the starting state of charge and the system error.

[0055] That is, during charging or discharging, the battery management system reports the state of charge in real time. The state of charge reported at the beginning of charging or discharging is recorded as the starting state of charge, and the state of charge reported at the end of charging or discharging is recorded as the ending state of charge. The difference between the ending state of charge and the starting state of charge is used as the second state of charge change detected by the battery management system during the charging or discharging phase. Furthermore, the difference between the second state of charge change and the first state of charge change is used to determine the system error of the battery management system with respect to the state of charge. This is then combined with the starting state of charge reported by the battery management system to calculate the initial state of charge after removing the system error, taking into account the system error. This improves the accuracy of the estimated state of charge.

[0056] Generally, the deviation between the SOC reported by the battery management system and the first SOC change is required to be less than 2%, which is used to ensure the accuracy of the battery management system's data collection. The SOC reported by the battery management system can be derived from the battery current, which further increases the accuracy of the battery management system's current sensor. If the SOC reported by the battery management system is highly accurate, the SOC reported by the battery management system can also be used directly as the reference SOC.

[0057] S103: Calculating the estimated state of charge of the power battery under multiple preset calculation strategies based on multiple battery parameters of the power battery.

[0058] The multiple preset calculation strategies include the ampere-hour integration method and the open-circuit voltage method. Specifically, the estimated state of charge refers to an estimated state of charge at the end of charging or discharging. The estimated state of charge is determined by: for each preset calculation strategy, determining a preset battery parameter corresponding to the preset calculation strategy from multiple battery parameters, and calculating the estimated state of charge of the power battery at the end of charging or discharging using the preset calculation strategy and the preset battery parameters.

[0059] Exemplarily, the battery current during the charging or discharging process is integrated over time and then compared with the rated capacity of the battery to obtain the third state of charge change of the battery that has been discharged or charged determined by the ampere-hour integration method, and the estimated state of charge corresponding to the ampere-hour integration method is obtained by the initial state of charge and the third state of charge change.

[0060] For example, based on the correspondence between the open circuit voltage (OCV) and the state of charge (SOC) of a power battery, the corresponding SOC is determined according to the battery voltage after the power battery is fully charged or discharged, and this SOC is used as the estimated SOC according to the open circuit voltage method. Alternatively, based on the correspondence between the open circuit voltage and the SOC of each power battery cell, the SOC of each cell is determined according to the cell voltage of each cell after the power battery is fully charged or discharged, thereby determining the SOC of the power battery based on the SOC of each cell, and using the SOC of the power battery as the estimated SOC according to the open circuit voltage method.

[0061] Among them, relative errors may also be introduced in this application. Relative errors include: the relationship curve between the open circuit voltage and state of charge (OCV-SOC) of the single cell may have errors, the single cell voltage may have sampling errors, the different voltages corresponding to multiple single cells lead to inconsistent states of charge, and the estimated state of charge corresponding to the open circuit voltage method may have errors, the plateau area of ​​the iron-lithium battery cannot be evaluated, and the state of charge corresponding to the voltage at the end of charging or discharging may not be completely consistent with the OCV-SOC curve. In other words, relative errors are errors that may be introduced by the open circuit voltage method, and the resulting relative errors are considered acceptable errors.

[0062] The preset calculation strategy may further include a Kalman filter method. There is no limitation on the specific method of the preset calculation strategy, and the state of charge of the power battery may be calculated.

[0063] S104: Determining, based on the estimated state of charge and the reference state of charge corresponding to each preset calculation strategy, an estimation accuracy of the power battery under the test environment and the charge / discharge parameters when charging or discharging.

[0064] The estimated state of charge corresponding to each preset calculation strategy can be subtracted from the reference state of charge to obtain the estimation error corresponding to each preset calculation strategy. If there is only one power battery, the estimation accuracy under each preset calculation strategy can be evaluated by comparing the magnitude of the estimation errors. The smaller the estimation error, the higher the estimation accuracy. If there are multiple power batteries, for each preset calculation strategy, the estimated errors corresponding to each power battery under the preset calculation strategy are calculated using methods such as the root mean square value, root mean square error, average value, and standard deviation to obtain an error evaluation for the preset calculation strategy. The estimation accuracy under each preset calculation strategy can be determined based on the error evaluation corresponding to each preset calculation strategy.

[0065] For example, after calculating the estimation accuracy, results analysis can be performed to analyze the accuracy differences between different estimation methods, identify factors affecting estimation accuracy, and, based on the analysis results, provide recommendations for improving the accuracy of power battery state of charge estimation. A test report can also be written, including the test method, test results, analysis, and recommendations.

[0066] Based on the same application concept, the embodiments of the present application also provide a state of charge estimation system corresponding to the method provided in the above embodiments. Since the principle of solving the problem by the state of charge estimation system in the embodiments of the present application is similar to the method in the above embodiments of the present application, the implementation of the state of charge estimation system can refer to the implementation of the method, and the repeated parts will not be repeated.

[0067] In an embodiment, the state of charge estimation system includes: a power battery; an environmental chamber, used to provide a test environment for the power battery, and the power battery is placed inside the environmental chamber; a charge and discharge tester, the charge and discharge tester is connected to the power battery to charge or discharge the power battery; and a processor, the processor is respectively connected to the power battery, the environmental chamber and the charge and discharge tester, and is used to execute the steps of the method described in any one of the above embodiments.

[0068] The charge and discharge tester should feature high precision, a wide range, multiple charge and discharge modes, and safety protection features. It should be able to precisely control the charge and discharge current and voltage, with current and voltage measurement accuracy within ±0.1%, ensuring accurate control and measurement of the battery charge and discharge process. It should also have a wide current and voltage output range to accommodate the testing needs of power batteries of different types and capacities. For example, the current output range can range from a few amperes to hundreds of amperes, and the voltage output range can range from a few volts to hundreds of volts. It should support multiple charge and discharge modes, including constant current charging, constant current discharging, constant voltage charging, and pulse charging and discharging, to simulate different operating conditions in actual use. Safety protection features such as overcurrent protection, overvoltage protection, and overheating protection ensure a safe and reliable testing process.

[0069] The processor is primarily used for data acquisition and must provide high-speed acquisition, multi-channel, high-precision data storage, and analysis capabilities. It should be able to collect battery parameters such as voltage, current, and temperature at a high sampling frequency (no less than 100Hz) to accurately capture the dynamic changes in the battery during the charge and discharge process. To reduce the size of test data, the static data collection interval during the charge and discharge process can be set to 1 second. It should have multiple acquisition channels to simultaneously collect multiple battery parameters or test multiple batteries. For example, it can simultaneously collect parameters such as the positive and negative voltages, current, and temperature of the battery. Parameter measurement accuracy should match that of the charge and discharge tester to ensure accurate and reliable data. For example, voltage measurement accuracy should be within ±0.1%, and current measurement accuracy should be within ±0.2%. The collected data should be stored and provided with data analysis software for data processing and analysis.

[0070] The temperature control performed by the environmental chamber should have the functions of precise temperature control, wide temperature range and stability. It should be able to accurately control the temperature of the test environment, and the temperature control accuracy should be within ±1°C. Temperature control can be achieved by using thermostats, heating plates, cooling fans and other equipment. It should have a wide temperature control range to adapt to different testing requirements. For example, the temperature control range can be from -40°C to 80°C to simulate the performance of the battery under different ambient temperatures. The temperature control system should have good stability to ensure that the temperature does not fluctuate significantly during the test. Furthermore, during the entire charging and discharging process, the battery temperature should be controlled to be within the required range of ±5°C through cooling or standing.

[0071] Furthermore, the accuracy of the state of charge estimation is tested by setting up an environmental chamber with adjustable temperature, a charge and discharge tester that can control the charge and discharge of the power battery and collect and record parameter data related to the power battery's state of charge in real time, and the power battery pack itself. The environmental chamber with adjustable temperature is mainly used to adjust and control the temperature of the test environment, so that the accuracy of the battery state of charge estimation under different temperature conditions can be tested, and the test environment conditions such as temperature and humidity can be controlled in real time. In addition, during the process of multiple charge and discharge and capacity decay of the battery, the parameters such as the single cell voltage, battery temperature, battery health status, battery capacity provided by the battery management system, and the BMS state of charge, charge and discharge current, and charge and discharge power provided by the tester will change. These parameter changes and the occurrence of faults that affect charging and discharging also determine the actual capacity of the battery, thereby affecting the estimation of the battery's true state of charge. By real-time collection and reporting of changes in various parameters that affect the state of charge during the battery charging and discharging process, receiving and displaying real-time collection and reporting of data during the charging and discharging process, and testing the real-time collection and reporting of various parameters and conditions that affect the battery's state of charge, the effectiveness and real-time performance of the battery management system's function of estimating the battery's state of charge are verified, thereby improving the reliability of battery management system development.

[0072] Based on the same application concept, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method provided in the above embodiment are executed.

[0073] Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, etc. When the computer program on the storage medium is run, the above method can be executed, by placing the power battery in an environmental chamber to provide a test environment for the power battery, and connecting the power battery through a charge and discharge tester to charge and discharge the power battery, and then collecting various battery parameters of the power battery during the charging and discharging process, and determining the reference state of charge of the power battery through the charge and discharge tester, and calculating the estimated state of charge according to a plurality of preset calculation strategies, so as to determine the estimation accuracy by using the reference state of charge and the estimated state of charge, and facilitate selecting the best estimation method to perform state of charge estimation, thereby solving the technical problem of inaccurate state of charge estimation in the prior art and achieving the technical effect of increasing the estimation accuracy of the state of charge.

[0074] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0075] The units described as separate components may or may not be physically separate, and 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 these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0076] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0077] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0078] The above are only specific embodiments of the present application, but the scope of protection of this 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. An information processing method for a state of charge estimation system, characterized in that: The state of charge estimation system includes a charge and discharge tester and an environmental chamber, wherein the power battery is placed inside the environmental chamber, and the charge and discharge tester is connected to the power battery to charge or discharge the power battery. The method comprises: Controlling the environmental chamber to provide the power battery with its corresponding test environment, and controlling the charge and discharge tester to charge or discharge according to the charge and discharge parameters corresponding to the power battery; collecting multiple battery parameters of the power battery in real time during the charging or discharging process, and determining a reference state of charge of the power battery by using the charge and discharge tester; Calculating the estimated state of charge of the power battery under multiple preset calculation strategies based on multiple battery parameters of the power battery; According to the estimated state of charge and the reference state of charge corresponding to each preset calculation strategy, the estimation accuracy of the power battery under each preset calculation strategy when charging or discharging in the test environment and the charge and discharge parameters is determined.

2. The method according to claim 1, characterized in that The reference state of charge refers to the state of charge of the power battery at the end of charging or discharging. The reference state of charge is determined by: determining a first state of charge change of the power battery by the charge and discharge tester at the end of charging or discharging, wherein the first state of charge change refers to the state of charge charged into the power battery during the charging process or the state of charge released from the power battery during the discharging process; A reference state of charge of the power battery at the end of charging or discharging is determined according to the initial state of charge of the power battery and the first state of charge change.

3. The method according to claim 2, characterized in that The estimated state of charge refers to the estimated state of charge at the end of charging or discharging, and the estimated state of charge is determined by: For each preset calculation strategy, a preset battery parameter corresponding to the preset calculation strategy is determined from multiple battery parameters, and the estimated state of charge of the power battery at the end of charging or discharging is calculated using the preset calculation strategy and the preset battery parameter.

4. The method according to claim 2 or 3, characterized in that The power battery includes a battery management system that determines the initial state of charge in the following manner: receiving a starting state of charge reported by the battery management system at the beginning of charging or discharging, and receiving an ending state of charge reported by the battery management system at the end of charging or discharging; determining a second state of charge change detected by the battery management system during a charging or discharging phase based on the ending state of charge and the starting state of charge; determining a system error of the battery management system based on the first state of charge change and the second state of charge change; The initial state of charge is calculated according to the starting state of charge and the system error.

5. The method according to claim 1, wherein The power battery is used in a vehicle, and the method further includes: Connecting the low-voltage interface of the power battery to a low-voltage constant-voltage source, and controlling the low-voltage constant-voltage source to transmit electrical energy to the low-voltage interface; Connecting the key door interface of the power battery to the first analog output interface, and controlling the first analog output interface to send a key door signal to the key door interface to wake up the power battery; Before charging the power battery, the charging gun interface of the power battery is connected to the second analog output interface, and the second analog output interface is controlled to send a charging gun connection signal to the charging gun interface to inform the power battery to be charged through the charging gun.

6. The method according to claim 1, characterized in that The power battery includes a battery management system, which is used to report multiple battery parameters. And / or, the multiple preset calculation strategies include an ampere-hour integration method and an open circuit voltage method.

7. The method according to claim 6, characterized in that The method further comprises: The fault type of the power battery is determined by the fault signal reported by the battery management system, so as to perform corresponding processing according to the fault type.

8. The method according to claim 1, characterized in that The power battery includes at least one, and each power battery has at least one different battery specification, wherein the battery specification includes battery type, usage level and battery specification.

9. A state of charge estimation system, characterized in that: The system comprises: Power batteries; An environmental chamber, used to provide the power battery with a corresponding test environment, wherein the power battery is placed inside the environmental chamber; a charge and discharge tester, connected to the power battery to charge or discharge the power battery; A processor, wherein the processor is respectively connected to the power battery, the environmental chamber, and the charge and discharge tester, and is used to execute the steps of any one of the methods described in claims 1 to 8.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are executed.

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