Battery state parameter calibration method, battery management system and electric two-wheeler
By acquiring the current and historical current and OCV values of the battery, and calibrating the battery state parameters using the preset SOC-OCV relationship, the problem of inaccurate battery state display in electric two-wheelers is solved, achieving high-precision estimation and management of battery state parameters, and improving the performance of the battery management system of electric two-wheelers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING YADEA TECHNOLOGY CO LTD
- Filing Date
- 2025-10-22
- Publication Date
- 2026-06-26
Smart Images
Figure CN122283508A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery management technology, and in particular to a battery state parameter calibration method, a battery management system, and an electric two-wheeler. Background Technology
[0002] Electric two-wheelers, as a convenient and economical short-distance transportation tool, have been widely used in urban and rural areas in recent years. As the core power source of electric two-wheelers, the performance of the battery pack directly affects the user's travel experience. Currently, mainstream electric two-wheelers still use lead-acid battery technology, mainly due to the mature manufacturing process and low production cost of lead-acid batteries. However, with the increasing demand for intelligent vehicles from users, traditional power display methods (such as simple three- or five-bar displays) can no longer meet users' needs for accurate battery status perception. Accurate display of battery status parameters, including remaining charge (SOC), state of health (SOH), and state of power (SOP), has become a core requirement. Currently, the battery management system (BMS) of electric two-wheelers typically uses a voltage comparison method for power estimation. This method is easily affected by factors such as temperature changes, battery aging, and load fluctuations, leading to a significant deviation between the displayed SOC and the actual remaining capacity. This deviation is further aggravated, especially in the later stages of battery use, causing inconvenience for users' travel planning. Summary of the Invention
[0003] This application provides a battery state parameter calibration method, a battery management system, and an electric two-wheeler to solve the problem of poor accuracy of battery state parameters in existing electric two-wheelers.
[0004] The technical solution provided in this application is as follows: In a first aspect, the present invention provides a battery state parameter calibration method, comprising: Obtain the battery's current current and current OCV value, as well as historical current and historical OCV values; The current SOC estimate of the battery is determined based on the current current and historical current. Based on the current OCV value, historical OCV value, current current, historical current, and the preset SOC-OCV correspondence, determine the current actual capacity of the battery; The current SOC estimate is calibrated based on the current actual capacity to obtain the calibrated current actual SOC value.
[0005] Optionally, obtain the battery's current current and current OCV value, including: Obtain the battery's current operating parameters, including current terminal voltage, current current, current temperature, and current cycle count. Input the current operating parameters into the battery equivalent circuit model to obtain the current internal resistance parameters that match the current operating parameters; The current OCV value is determined based on the current internal resistance parameter, the current terminal voltage, and the current current.
[0006] Optionally, before obtaining the battery's current current and current OCV value, the following steps are also included: Establish an equivalent circuit model composed of a second-order RC network; Based on the SOC-OCV curves at different battery temperatures, the DCR curves at different cycle numbers, and the test parameters, the parameters of the equivalent circuit model are identified, and multiple sets of internal resistance parameters in the equivalent circuit model are obtained.
[0007] Optionally, based on the current OCV value, historical OCV values, current current, historical current, and a preset SOC-OCV correspondence, the current actual capacity of the battery is determined, including: Based on the preset SOC-OCV relationship, the historical test SOC value corresponding to the historical OCV value at the current battery temperature and the current test SOC value corresponding to the current OCV value are determined. The cumulative charge and discharge capacity is determined based on the current current and historical current. The current actual capacity of the battery is determined based on the cumulative charge and discharge capacity, historical test SOC value, and current test SOC value.
[0008] Optionally, the current SOC estimate is calibrated based on the current actual capacity to obtain the calibrated current actual SOC value, including: Get the current remaining battery level; The current SOC calibration value is determined based on the ratio of the current remaining power to the current actual capacity. The actual value of the current SOC is determined based on the current SOC calibration value and the current SOC estimate.
[0009] Optionally, the actual current SOC value is determined based on the current SOC calibration value and the current SOC estimate, including: When the difference between the current SOC calibration value and the current SOC estimate value is not greater than the first threshold, the current SOC calibration value or the current SOC estimate value is taken as the current actual SOC value. When the difference between the current SOC calibration value and the current SOC estimate value is greater than the first threshold and less than the second threshold, the average of the current SOC calibration value and the current SOC estimate value is taken as the current actual SOC value. When the difference between the current SOC calibration value and the current SOC estimate value is greater than the second threshold, the smaller SOC value between the current SOC calibration value and the current SOC estimate value is taken as the current actual SOC value.
[0010] Optionally, after calibrating the current SOC estimate based on the current actual capacity to obtain the calibrated current SOC actual value, the following steps are also included: Based on the preset relationship between OCV value, SOC value and maximum discharge current, the maximum discharge current corresponding to the current OCV value and the current actual SOC value is taken as the current maximum discharge current; Determine the target battery terminal voltage based on the current maximum discharge current, the current OCV value, and the current internal resistance parameter; Determine the current maximum discharge power based on the current maximum discharge current and the target battery terminal voltage.
[0011] Optionally, after determining the battery's current actual capacity based on the current OCV value, historical OCV value, current current, historical current, and a preset SOC-OCV correspondence, the following steps are also included: Obtain the rated capacity of the battery; The current actual SOH value of the battery is determined based on the current actual capacity and the rated capacity.
[0012] Secondly, the present invention provides a battery management system, comprising: a data acquisition unit, a communication unit, and a main control unit; the data acquisition unit is connected to the main control unit through the communication unit; the data acquisition unit is also connected to a battery. The data acquisition unit is used to collect the battery's operating parameters; the communication unit is used to transmit the operating parameters to the main control unit; the main control unit is used to execute the aforementioned battery state parameter calibration method.
[0013] Thirdly, the present invention provides an electric two-wheeled vehicle, including: the aforementioned battery management system.
[0014] The beneficial effects of this application are as follows: In this application, the actual SOC change represented by the current OCV value, historical OCV value, and preset SOC-OCV correspondence are used to deduce the actual SOC change represented by these two OCV values. Then, the current actual capacity is determined based on the current current, historical current, and actual SOC change. The current SOC estimate is calibrated based on the current actual capacity, that is, the nominal capacity in the original model is replaced with the more accurate actual capacity, thereby correcting the cumulative error of the ampere-hour integration method. This effectively overcomes the problem of accumulated SOC estimation error caused by battery aging, temperature changes, and fluctuations in operating conditions, significantly improving the estimation accuracy and reliability of SOC throughout the entire life cycle, and improving the accuracy of battery state parameters of electric two-wheelers. This provides a precise data foundation for battery equalization management, safety warning, and life extension.
[0015] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description
[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram outlining the battery state parameter calibration method in the embodiments of this application; Figure 2 This is a schematic diagram illustrating the specific process of determining the current internal resistance parameter in the embodiments of this application; Figure 3 This is a schematic diagram of the equivalent circuit model constructed by a second-order RC network in an embodiment of this application; Figure 4 This is a SOC-OCV curve diagram from an embodiment of this application; Figure 5 This is a DCR curve diagram from an embodiment of this application; Figure 6 This is a schematic diagram illustrating the specific process of determining the actual value of the current SOC in this embodiment of the application; Figure 7 This is a schematic diagram of the battery management system in an embodiment of this application. Detailed Implementation
[0017] To make the objectives, technical solutions, and beneficial effects of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0018] This application provides a battery state parameter calibration method applied to lead-acid batteries. (See attached document.) Figure 1 As shown, the general flow of the battery state parameter calibration method provided in this application embodiment is as follows: Step 101: Obtain the current current and current OCV value of the battery, as well as the historical current and historical OCV value.
[0019] In practical applications, the current current refers to the instantaneous current value measured in real time by the current sensor in the Battery Management System (BMS). The sign of the current current indicates whether it is charging or discharging. The current OCV value is the open-circuit voltage value calculated at the current moment based on the battery equivalent circuit model and real-time measurement parameters. The historical current refers to the current measured and stored from the first moment to the current moment, and the historical OCV value is the calculated open-circuit voltage value at the first moment. The first moment is either the start of the current calibration cycle or the previous moment selected as the reference point.
[0020] Step 102: Determine the current SOC estimate of the battery based on the current current and historical current.
[0021] In practical applications, the ampere-hour integration method is used to estimate the state of charge (SOC) of the battery. First, an initial SOC value is obtained, which is the SOC value at the first moment. Then, by integrating the entire current time series from the first moment to the current moment, the cumulative charge / discharge capacity is calculated. The sum of the ratio of the cumulative charge / discharge capacity to the battery's rated capacity and the initial SOC value is used as the estimated current SOC value.
[0022] Step 103: Determine the current actual capacity of the battery based on the current OCV value, historical OCV value, current current, historical current, and the preset SOC-OCV correspondence.
[0023] In practical applications, the SOC-OCV correspondence measured in the laboratory for this type of battery at different temperatures is used to find the corresponding current test SOC value and historical test SOC value by comparing the current OCV value with the historical OCV value. The ampere-hour integration method is calibrated based on the difference between the current test SOC value and the historical test SOC value to obtain the cumulative error in the current SOC estimate, and the current actual capacity of the battery is calculated.
[0024] Step 104: Calibrate the current SOC estimate based on the current actual capacity to obtain the calibrated current SOC actual value.
[0025] In practical applications, the current actual capacity is input into the SOC algorithm model of the BMS to obtain the current SOC calibration value. The current SOC actual value after calibration is determined by comparing the current SOC estimate and the current SOC calibration value.
[0026] In this way, by using the current OCV value, historical OCV value, and the preset SOC-OCV correspondence, the actual SOC change represented by these two OCV values can be deduced. Then, based on the current current, historical current, and the actual SOC change, the current actual capacity is determined. The current SOC estimate is calibrated based on the current actual capacity, that is, the nominal capacity in the original model is replaced with the newly calculated, more accurate actual capacity, thereby correcting the cumulative error of the ampere-hour integration method. This effectively overcomes the problem of accumulated SOC estimation error caused by battery aging, temperature changes, and fluctuations in operating conditions, and significantly improves the estimation accuracy and reliability of SOC throughout the entire life cycle, thus providing an accurate data foundation for battery equalization management, safety warning, and life extension.
[0027] In one possible implementation, see [reference] Figure 2 As shown, the current current and current OCV value of the battery are obtained, including: Step 201: Obtain the current operating parameters of the battery; wherein, the current operating parameters include the current terminal voltage, current current, current temperature and current cycle number.
[0028] In practical applications, the current terminal voltage refers to the terminal voltage value measured directly at the battery terminals by the BMS's voltage sensor at the current moment. The current current refers to the current value measured directly at the battery terminals by the BMS's current sensor at the current moment. The current temperature is the battery temperature measured at the current moment by a temperature sensor located on the battery body. The current cycle count is the cumulative charge-discharge cycle count read from the BMS's non-volatile memory.
[0029] Step 202: Input the current operating parameters into the battery equivalent circuit model to obtain the current internal resistance parameters that match the current operating parameters.
[0030] In practical applications, the battery equivalent circuit model has been pre-parameterized using extensive experimental data for different combinations of terminal voltage, current, temperature, and cycle count, generating a multi-dimensional parameter mapping table. By using the real-time acquired operating parameters as input indexes and querying this built-in multi-dimensional parameter mapping table, a set of current internal resistance parameters matching the current battery operating state can be instantly assigned to each resistive element in the equivalent circuit model. These current internal resistance parameters include the current ohmic internal resistance and the current polarization internal resistance.
[0031] In practice, before obtaining the battery's current current and current OCV value, the construction of the battery's equivalent circuit model can adopt, but is not limited to, the following methods: First, an equivalent circuit model consisting of a second-order RC network is established.
[0032] Then, based on the SOC-OCV curves at different battery temperatures, the DCR curves at different cycle numbers, and the test parameters, the parameters of the equivalent circuit model are identified, and multiple sets of internal resistance parameters in the equivalent circuit model are obtained.
[0033] In practical applications, the equivalent circuit model of a second-order RC network is as follows: Figure 3 As shown, the equivalent circuit model includes an ideal voltage source representing the battery open-circuit voltage, affected by SOC and temperature; a resistor R0 representing the battery's ohmic internal resistance, affected by SOH and temperature; and a second-order RC network representing the battery's polarization internal resistance. The second-order RC network structure aims to more accurately fit the battery's voltage relaxation response characteristics with dual time constants when excited by a pulsed current. Compared to the first-order model, it provides higher voltage prediction accuracy, especially under dynamic operating conditions. In the figure, U_tv represents the battery terminal voltage, U_ocv represents the battery open-circuit voltage, and U_ecm represents the voltage drop due to DC internal resistance. Based on this equivalent circuit model, the following set of equations can be established: U_tv = U_ocv - U_ecm U_ecm=U_r0+U_rc1+U_rc2 I = I_r + I_c Where U_r0 is the voltage across resistor R0, U_rc1 is the voltage across resistor R1, U_rc2 is the voltage across resistor R2, I is the battery current, I_r is the current flowing through resistor R1, and I_c is the current flowing through capacitor.
[0034] During the experiment, the laboratory conducted OCV-SOC curve tests on lead-acid batteries at different temperatures, obtaining the following results: Figure 4 The SOC-OCV curves are shown at different battery temperatures; hybrid pulse power characteristics (HPPC) tests were performed at different temperatures and lifetimes, yielding the following results: Figure 5 The DCR curves shown represent the relationship between the battery's ohmic internal resistance and temperature at different cycle numbers. Both tests were conducted under identical temperature conditions, with the battery's terminal voltage and current acquired in real-time during the tests. Based on the acquired battery terminal voltage and current, SOC-OCV curves, and DCR curves, parameter identification was performed on the equivalent circuit model. For each state point composed of battery terminal voltage, battery current, battery temperature, and battery cycle number, a matching set of internal resistance parameters was determined. These internal resistance parameters include the parameter value of the resistor R0 representing the battery's ohmic internal resistance and the parameter value of the second-order RC network representing the battery's polarization internal resistance. Multiple state points and their corresponding matching internal resistance parameters are stored in a multi-dimensional parameter mapping table format.
[0035] Step 203: Determine the current OCV value based on the current internal resistance parameter, current terminal voltage, and current current.
[0036] In practical applications, the current DC internal resistance can be determined based on the current internal resistance parameters. The current DC internal resistance is the sum of the ohmic internal resistance and the polarization internal resistance values in the current internal resistance parameters. The current DC internal resistance voltage drop is determined by multiplying the current DC internal resistance by the current current. The current terminal voltage plus the current DC internal resistance voltage drop yields the current OCV value.
[0037] Thus, this invention equates the current-voltage response characteristics of lead-acid batteries to a simplified circuit model. This circuit model can describe the dynamic characteristics of lead-acid batteries, such as the terminal voltage response and DC internal resistance changes during charging and discharging. By conducting charge-discharge tests and HPPC hybrid pulse tests under different battery environments in the laboratory, the OCV-SOC curves and DC internal resistance (DCR) curves of lead-acid batteries under different conditions can be obtained. By using a lookup table method, the corresponding test parameters are input into the equivalent circuit model of a second-order RC network under different environments for parameter identification. After identification, the corresponding RC parameters in the equivalent circuit model can be updated, thereby obtaining the accurate DC internal resistance of the battery under the current state, providing an accurate data basis for battery state parameter calibration.
[0038] In one possible implementation, the current actual capacity of the battery is determined based on the current OCV value, historical OCV value, current current, historical current, and a preset SOC-OCV correspondence. This can be achieved using, but is not limited to, the following methods: First, based on the preset SOC-OCV relationship, the historical test SOC value corresponding to the historical OCV value at the current battery temperature and the current test SOC value corresponding to the current OCV value are determined.
[0039] Then, the cumulative charge and discharge capacity is determined based on the current and historical current.
[0040] Finally, the current actual capacity of the battery is determined based on the cumulative charge and discharge capacity, historical test SOC value, and current test SOC value.
[0041] In practical applications, based on the current battery temperature, a curve matching the current temperature is selected from a pre-set library of SOC-OCV curves for different temperatures. Then, historical and current OCV values are input into the selected curve for reverse lookup, yielding historical and current test SOC values. The change in current SOC is calculated by subtracting the historical SOC value from the current SOC value. Based on historical and current current, ampere-hour integration is performed to calculate the cumulative charge / discharge capacity from the first time point to the current time. Finally, the current actual capacity is calculated using the following formula.
[0042] C_now=∫Idt / ΔSOC Where C_now is the current actual capacity, ∫Idt is the cumulative charge and discharge capacity, and ΔSOC is the current change in SOC.
[0043] In one possible implementation, see [reference] Figure 6 As shown, the current estimated SOC value is calibrated based on the current actual capacity to obtain the calibrated actual SOC value. This can be achieved, but is not limited to, the following methods: Step 601: Obtain the current remaining battery power. The current remaining battery power is the net battery power value obtained by the BMS after integrating all discharge and charging currents in ampere-hours, starting from a fully charged state.
[0044] Step 602: Determine the current SOC calibration value based on the ratio of the current remaining power to the current actual capacity.
[0045] Step 603: Determine the current actual SOC value based on the current SOC calibration value and the current estimated SOC value.
[0046] In practice, the actual SOC value is determined based on the current SOC calibration value and the current SOC estimate value, which may include, but is not limited to, the following situations: The first scenario: When the difference between the current SOC calibration value and the current SOC estimate value is not greater than the first threshold, the current SOC calibration value or the current SOC estimate value is taken as the current actual SOC value.
[0047] In practical applications, if the difference between the current SOC calibration value and the current SOC estimate is no greater than the first threshold, it indicates that the cumulative error of the ampere-hour integration method is very small within this time period. Therefore, either the current SOC calibration value or the current SOC estimate can be selected as the actual current SOC value. The first threshold represents the maximum permissible deviation between the current SOC calibration value and the current SOC estimate.
[0048] The second scenario: When the difference between the current SOC calibration value and the current SOC estimate value is greater than the first threshold but less than the second threshold, the average of the current SOC calibration value and the current SOC estimate value is taken as the current actual SOC value.
[0049] In practical applications, if the difference between the current SOC calibration value and the current SOC estimate is greater than the first threshold but less than the second threshold, it corresponds to a moderate deviation within a reasonable range. To ensure a smooth transition and reduce the risk of sudden changes, the arithmetic mean of the current SOC calibration value and the current SOC estimate is used as the actual current SOC value. The second threshold is greater than the first threshold, and it represents the maximum safe deviation determined based on system safety redundancy and fault detection sensitivity requirements.
[0050] The third scenario: When the difference between the current SOC calibration value and the current SOC estimate value is greater than the second threshold, the smaller SOC value between the current SOC calibration value and the current SOC estimate value is taken as the current actual SOC value.
[0051] In practical applications, when the difference between the current calibrated SOC value and the current estimated SOC value exceeds the second threshold, for safety and conservatism, the smaller SOC value is taken as the actual current SOC value. Furthermore, in a third scenario, when the difference between the current calibrated SOC value and the current estimated SOC value is determined to be greater than the second threshold, historical temperatures are also retrieved to determine if the difference between the current temperature and the historical temperature exceeds a preset temperature threshold. If so, it is determined that a sudden change in the battery's operating environment has occurred. For lead-acid batteries, a sudden temperature change immediately causes a significant change in the electrolyte viscosity and internal resistance, resulting in a large deviation between the battery internal resistance identified based on previous temperature parameters and the calculated OCV value and the current actual situation within a short period. This deviation is non-faulty and temporary. In this case, the event can be recorded, and the system may be allowed to stabilize at the new temperature instead of immediately issuing an alarm, thus avoiding false alarms. If not, the battery anomaly alarm procedure is executed, notifying the user or maintenance system to conduct an emergency check, ruling out the possibility that a sudden environmental change is the primary cause. At this point, a significant SOC difference is more likely due to other anomalies, such as calibration drift or malfunction of the current or voltage sensor, abnormally increased contact resistance at battery connection points, or internal short circuits within the battery. Given the potential danger of this situation, an immediate battery anomaly alarm should be triggered. This alarm will notify the user or the backend monitoring system via dashboard icons, sounds, or remote signals, prompting professional inspection and maintenance to ensure safety.
[0052] In one possible implementation, after calibrating the current SOC estimate based on the current actual capacity to obtain the calibrated current SOC actual value, the maximum discharge power can also be calibrated based on the current SOC actual value. Specifically, this can be achieved, but is not limited to, the following methods: First, based on the preset relationship between OCV value, SOC value and maximum discharge current, the maximum discharge current corresponding to the current OCV value and the current actual SOC value is taken as the current maximum discharge current; Then, the target battery terminal voltage is determined based on the current maximum discharge current, the current OCV value, and the current internal resistance parameter; Finally, the current maximum discharge power is determined based on the current maximum discharge current and the target battery terminal voltage.
[0053] In practical applications, a three-dimensional mapping table generated through experiments and model simulations is pre-stored. This table defines the maximum continuous discharge current that the battery can provide under different combinations of OCV and SOC. Using the calibrated, more accurate current OCV value and the actual current SOC value as joint inputs, this mapping table can be consulted to obtain the corresponding current maximum discharge current. The current DC internal resistance can be determined based on the current internal resistance parameter. The current maximum DC internal resistance voltage drop is determined by multiplying the current DC internal resistance by the maximum discharge current. Subtracting the current maximum DC internal resistance voltage drop from the current OCV value yields the target battery terminal voltage. The product of the current maximum discharge current and the target battery terminal voltage is taken as the current maximum discharge power. This provides an accurate data foundation for estimating the remaining driving range of the entire vehicle.
[0054] In one possible implementation, after determining the battery's current actual capacity based on the current OCV value, historical OCV value, current current, historical current, and a preset SOC-OCV correspondence, the battery's SOH value can be calibrated according to the battery's current actual capacity. This can be achieved, but is not limited to, the following methods: First, obtain the battery's rated capacity; Then, determine the current actual SOH value of the battery based on the current actual capacity and rated capacity.
[0055] In practical applications, rated capacity is the nominal amount of electricity a brand-new battery can provide under standard conditions; it is a fixed parameter stored in the BMS's memory. Dividing the current actual capacity by the rated capacity and then multiplying by 100% yields the accurate current SOH (State of Health) value. The battery's current SOH value directly reflects the battery's capacity degradation and is an important indicator for assessing whether the battery needs maintenance or replacement.
[0056] Based on the above embodiments, this application provides a battery management system, see below. Figure 7 As shown, the battery management system 700 provided in this application embodiment includes at least: a data acquisition unit 701, a communication unit 702, and a main control unit 703; the data acquisition unit 701 is connected to the main control unit 703 through the communication unit 702; the data acquisition unit 701 is also connected to the battery; The data acquisition unit 701 is used to acquire the battery's operating parameters; the communication unit 702 is used to transmit the operating parameters to the main control unit 703; the main control unit 703 is used to execute the above-mentioned battery state parameter calibration method.
[0057] Based on the above embodiments, this application provides an electric two-wheeled vehicle, which includes at least the above-mentioned battery management system.
[0058] The program product provided in this application embodiment can be any combination of one or more readable media, wherein the readable media can be a readable signal medium or a readable storage medium, and the readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination thereof. Specifically, more specific examples of readable storage media (a non-exhaustive list) include: electrical connections with one or more wires, portable disks, hard disks, RAM, ROM, erasable programmable read-only memory (EPROM), optical fibers, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.
[0059] The program product provided in this application embodiment can be a CD-ROM and include program code, and can also run on a computing device. However, the program product provided in this application embodiment is not limited thereto. In this application embodiment, the readable storage medium can be any tangible medium that contains or stores a program, which can be used by or in conjunction with an instruction execution system, apparatus, or device.
[0060] It should be noted that although several units or sub-units of the device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units.
[0061] Furthermore, although the operations of the method of this application are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.
[0062] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.
[0063] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.
Claims
1. A method for calibrating battery state parameters, characterized in that, include: Obtain the battery's current current and current OCV value, as well as historical current and historical OCV values; The current SOC estimate of the battery is determined based on the current current and the historical current; Based on the current OCV value, the historical OCV value, the current current, the historical current, and the preset SOC-OCV correspondence, the current actual capacity of the battery is determined; The current SOC estimate is calibrated based on the current actual capacity to obtain the calibrated current actual SOC value.
2. The battery state parameter calibration method as described in claim 1, characterized in that, The acquisition of the battery's current current and current OCV value includes: Obtain the current operating parameters of the battery; wherein, the current operating parameters include the current terminal voltage, current current, current temperature, and current cycle count; The current operating parameters are input into the battery equivalent circuit model to obtain the current internal resistance parameters that match the current operating parameters; The current OCV value is determined based on the current internal resistance parameter, the current terminal voltage, and the current current.
3. The battery state parameter calibration method as described in claim 2, characterized in that, Before obtaining the battery's current current and current OCV value, the following steps are also included: Establish an equivalent circuit model composed of a second-order RC network; Based on the SOC-OCV curves at different battery temperatures, the DCR curves at different cycle numbers, and the test parameters, the equivalent circuit model is parameter identified to obtain multiple sets of internal resistance parameters in the equivalent circuit model.
4. The battery state parameter calibration method as described in claim 1, characterized in that, The step of determining the current actual capacity of the battery based on the current OCV value, the historical OCV value, the current current, the historical current, and the preset SOC-OCV correspondence includes: Based on the preset SOC-OCV relationship, the historical test SOC value corresponding to the historical OCV value and the current test SOC value corresponding to the current OCV value are determined at the current battery temperature; The cumulative charge / discharge capacity is determined based on the current current and the historical current. The current actual capacity of the battery is determined based on the cumulative charge and discharge capacity, the historical test SOC value, and the current test SOC value.
5. The battery state parameter calibration method as described in claim 1, characterized in that, The step of calibrating the current SOC estimate based on the current actual capacity to obtain the calibrated current actual SOC value includes: Get the current remaining battery level; The current SOC calibration value is determined based on the ratio of the current remaining power to the current actual capacity; The actual value of the current SOC is determined based on the current SOC calibration value and the current SOC estimate value.
6. The battery state parameter calibration method as described in claim 5, characterized in that, The step of determining the actual current SOC value based on the current SOC calibration value and the current SOC estimate includes: When the difference between the current SOC calibration value and the current SOC estimate value is not greater than a first threshold, the current SOC calibration value or the current SOC estimate value is taken as the current SOC actual value. When the difference between the current SOC calibration value and the current SOC estimate value is greater than the first threshold and less than the second threshold, the average value of the current SOC calibration value and the current SOC estimate value is taken as the current SOC actual value. When the difference between the current SOC calibration value and the current SOC estimate value is greater than the second threshold, the smaller SOC value between the current SOC calibration value and the current SOC estimate value is taken as the current actual SOC value.
7. The battery state parameter calibration method as described in claim 2, characterized in that, After calibrating the current SOC estimate based on the current actual capacity to obtain the calibrated current SOC actual value, the method further includes: Based on the preset relationship between OCV value, SOC value and maximum discharge current, the maximum discharge current corresponding to the current OCV value and the current actual SOC value is taken as the current maximum discharge current; The target battery terminal voltage is determined based on the current maximum discharge current, the current OCV value, and the current internal resistance parameter. The current maximum discharge power is determined based on the current maximum discharge current and the target battery terminal voltage.
8. The battery state parameter calibration method according to any one of claims 1-7, characterized in that, After determining the current actual capacity of the battery based on the current OCV value, the historical OCV value, the current current, the historical current, and the preset SOC-OCV correspondence, the method further includes: Obtain the rated capacity of the battery; The current SOH value of the battery is determined based on the current actual capacity and the rated capacity.
9. A battery management system, characterized in that, include: The system includes a data acquisition unit, a communication unit, and a main control unit; the data acquisition unit is connected to the main control unit via the communication unit; the data acquisition unit is also connected to a battery. The data acquisition unit is used to acquire the battery's operating parameters; the communication unit is used to transmit the operating parameters to the main control unit; the main control unit is used to execute the battery state parameter calibration method as described in any one of claims 1-8.
10. An electric two-wheeled vehicle, characterized in that, include: The battery management system as described in claim 9.