Battery model parameter identification method and device and engineering vehicle

Abstract

The application relates to a battery model parameter identification method and device and an engineering vehicle, and relates to the technical field of batteries. The battery model parameter identification method comprises the following steps: obtaining a corresponding relationship between a state of charge of a battery and an open-circuit voltage of the battery under a preset working condition; obtaining a target relationship formula according to a preset battery equivalent circuit model; obtaining total current and terminal voltage in the preset battery equivalent circuit model in different test periods by running the preset battery equivalent circuit model; and obtaining target parameters in the preset battery equivalent circuit model under different states of charge according to the corresponding relationship between the state of charge and the open-circuit voltage, the target relationship formula, the total current in the multiple test periods and the terminal voltage in the multiple test periods. The battery model parameter identification method, device and engineering vehicle can obtain more accurate parameters, thereby improving the accuracy of the battery equivalent circuit model.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a method, device, and engineering vehicle for identifying battery model parameters. Background Technology

[0002] Currently, battery equivalent circuit models can be applied in BMS (Battery Management System). These models can be used to estimate the battery's SOC (State of Charge). Accurate prediction of the battery's SOC requires an accurate battery equivalent circuit model, and the accuracy of this model largely depends on the accuracy of its parameters. Existing technologies typically employ HPPC (High-Performance Computational Processing) experiments to identify these parameters. However, the identification process uses segmented calculations, utilizing data from resting and discharging periods separately. This results in significant accumulated errors, leading to low accuracy of the ultimately identified model parameters. Summary of the Invention

[0003] To address the aforementioned technical problems, embodiments of this application provide a battery model parameter identification method, apparatus, and engineering vehicle, which can obtain more accurate parameters, thereby improving the accuracy of the battery equivalent circuit model.

[0004] Firstly, a method for identifying battery model parameters is provided, including:

[0005] Obtain the correspondence between the state of charge of the battery and the open-circuit voltage of the battery under preset operating conditions; wherein, the preset operating conditions include multiple test cycles, and different test cycles include the discharge stage and the resting stage of the battery under different states of charge;

[0006] Based on the preset battery equivalent circuit model, the target relationship is calculated; wherein, the target relationship includes the relationship between the total current in the preset battery equivalent circuit model and the polarization current in the preset battery equivalent circuit model.

[0007] By running the preset battery equivalent circuit model, the total current and terminal voltage in the preset battery equivalent circuit model are obtained during different test cycles; and

[0008] Based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, the target parameters in the preset battery equivalent circuit model under different states of charge are calculated.

[0009] According to a first aspect of this application, obtaining the correspondence between the state of charge of the battery under preset operating conditions and the open-circuit voltage of the battery includes:

[0010] Control the battery to discharge and rest under different states of charge;

[0011] Obtain the open-circuit voltage of the battery after it has been left to rest under different states of charge; and

[0012] Based on the different states of charge and the corresponding open-circuit voltage after resting, the correspondence between the state of charge of the battery and the open-circuit voltage of the battery is obtained.

[0013] According to a first aspect of this application, controlling the battery to discharge and rest under different states of charge includes:

[0014] Control the battery to discharge under its current state of charge;

[0015] Control the battery to remain stationary for a first preset time;

[0016] Adjusting the state of charge of the battery; and

[0017] The battery is controlled to remain stationary for a second preset time under the adjusted state of charge.

[0018] According to a first aspect of this application, obtaining the correspondence between the state of charge of the battery and the open-circuit voltage of the battery based on different states of charge and the corresponding open-circuit voltage after resting includes:

[0019] Based on the different states of charge and the corresponding open-circuit voltage after resting, multiple distribution points of the states of charge and the open-circuit voltage are obtained;

[0020] Within different state-of-charge intervals, additional target points are added to the multiple distribution points at different state-of-charge intervals; and

[0021] Based on multiple distribution points and multiple target points, a relationship curve characterizing the correspondence between the state of charge of the battery and the open-circuit voltage of the battery is obtained by fitting.

[0022] According to a first aspect of this application, adding additional target points among the plurality of distribution points within different state-of-charge intervals includes:

[0023] Within the first state of charge interval, additional target points are added within the first state of charge interval by a first state of charge interval value;

[0024] Within the second state of charge interval, additional target points are added at second state of charge intervals; wherein any state of charge value within the second state of charge interval is greater than the maximum state of charge value within the first state of charge interval; and the second state of charge interval is greater than the first state of charge interval; and...

[0025] Within the third state of charge interval, additional target points are added within the third state of charge interval by a third state of charge interval value; wherein any state of charge value within the third state of charge interval is greater than the maximum state of charge value within the second state of charge interval; and the third state of charge interval value is less than the second state of charge interval value.

[0026] According to a first aspect of this application, after calculating the target parameters in the preset battery equivalent circuit model under different states of charge, the battery model parameter identification method further includes:

[0027] Based on the target parameters, the preset battery equivalent circuit model is run to obtain the fitted terminal voltage under the target state of charge.

[0028] Obtain the actual terminal voltage of the battery under the target state of charge; and

[0029] Based on the fitted terminal voltage and the actual terminal voltage, the fitting accuracy result is output.

[0030] According to a first aspect of this application, after the output fitting accuracy result, the battery model parameter identification method further includes:

[0031] If the voltage difference represented by the fitting accuracy result is less than or equal to the voltage threshold, then output a signal that retains the target parameters; or

[0032] If the voltage difference represented by the fitting accuracy result is greater than the voltage threshold, then the number of sampling points in each test cycle is increased; wherein, the sampling point represents the time node for acquiring the total current and the terminal voltage;

[0033] Run the preset battery equivalent circuit model again to obtain the total current and terminal voltage in the preset battery equivalent circuit model during the test period after adding the sampling points;

[0034] Based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, new target parameters in the preset battery equivalent circuit model under different states of charge are calculated.

[0035] Secondly, a battery model parameter identification device is also provided, comprising:

[0036] The first acquisition module is configured to acquire the correspondence between the state of charge of the battery and the open-circuit voltage of the battery under preset operating conditions; wherein, the preset operating conditions include multiple test cycles, and different test cycles include the discharge stage and the resting stage of the battery under different states of charge;

[0037] The first calculation module is configured to calculate a target relation based on a preset battery equivalent circuit model; wherein the target relation includes the relationship between the total current in the preset battery equivalent circuit model and the polarization current in the preset battery equivalent circuit model.

[0038] The first measurement module is configured to run the preset battery equivalent circuit model to obtain the total current and terminal voltage in the preset battery equivalent circuit model during different test cycles; and

[0039] The second calculation module is configured to calculate the target parameters in the preset battery equivalent circuit model under different states of charge based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles.

[0040] Thirdly, an engineering vehicle is also provided, including:

[0041] Vehicle body;

[0042] The battery model parameter identification device described above is located on the vehicle body.

[0043] Fourthly, an engineering vehicle is also provided, including:

[0044] Vehicle body;

[0045] An electronic device, located on the vehicle body, is configured to perform the battery model parameter identification method as described above.

[0046] Fifthly, a storage medium is also provided, the storage medium storing a computer program configured to execute the battery model parameter identification method as described above.

[0047] The battery model parameter identification method, device, engineering vehicle, and storage medium provided in this application embodiment obtain the correspondence between the battery's state of charge and open-circuit voltage under preset operating conditions. Then, based on a preset battery equivalent circuit model, a target relationship is calculated. The preset battery equivalent circuit model is then run to obtain the total current and terminal voltage in the preset battery equivalent circuit within different test cycles. Finally, based on the correspondence between the state of charge and open-circuit voltage, the target relationship, the total current within multiple test cycles, and the terminal voltage within multiple test cycles, the target parameters in the preset battery equivalent circuit model under different state of charge are calculated. Since the total current can be actually measured by an ammeter in the same test cycle, whether in the discharge stage or the resting stage, the accuracy of the total current measurement is not affected by discharge or resting. Therefore, when applying the target relationship for calculation, the total current data of the discharge stage and the resting stage can be used simultaneously without segmented calculation. The total current data of the discharge stage and the resting stage are used as input data for calculation simultaneously, eliminating the cumulative error in the segmented calculation process and improving the accuracy of the final calculated target parameters. Attached Figure Description

[0048] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0049] Figure 1 This is a flowchart illustrating a battery model parameter identification method provided as an exemplary embodiment of this application.

[0050] Figure 2 A schematic diagram of the structure of a preset battery equivalent circuit model provided for an exemplary embodiment of this application.

[0051] Figure 3 This is a schematic flowchart illustrating the correspondence between the state of charge of a battery and its open-circuit voltage under preset operating conditions, provided as an exemplary embodiment of this application.

[0052] Figure 4 This is a schematic diagram illustrating the process of controlling a battery to discharge and rest under different states of charge, provided as an exemplary embodiment of this application.

[0053] Figure 5 This is a schematic flowchart illustrating the correspondence between the state of charge and the open-circuit voltage of a battery based on different states of charge and the corresponding open-circuit voltage after resting, as provided in an exemplary embodiment of this application.

[0054] Figure 6 This is a flowchart illustrating the process of adding additional target points at multiple distribution points within different state-of-charge intervals, as provided in an exemplary embodiment of this application.

[0055] Figure 7 A schematic flowchart of a battery model parameter identification method provided for another exemplary embodiment of this application.

[0056] Figure 8 A schematic flowchart of a battery model parameter identification method provided for another exemplary embodiment of this application.

[0057] Figure 9 This is a structural block diagram of a battery model parameter identification device provided as an exemplary embodiment of this application.

[0058] Figure 10 A structural block diagram of a battery model parameter identification device provided for another exemplary embodiment of this application.

[0059] Figure 11 A structural block diagram of an engineering vehicle provided for an exemplary embodiment of this application.

[0060] Figure 12 A structural block diagram of an engineering vehicle provided for another exemplary embodiment of this application.

[0061] Figure 13 A structural block diagram of an electronic device provided for an exemplary embodiment of this application. Detailed Implementation

[0062] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0063] Currently, battery equivalent circuit models can be applied in BMS (Battery Management System). The battery's SOC (State of Charge) can be estimated using the battery equivalent circuit model. In order to accurately predict the battery's SOC, an accurate battery equivalent circuit model is required. The accuracy of the battery equivalent circuit model mainly depends on the accuracy of the model parameters in the battery equivalent circuit model.

[0064] In existing technologies, HPPC (High-Performance Circuit Probe) experiments are typically used to identify model parameters. Specifically, the battery is discharged and left to stand to obtain test data for the discharge and stand periods. Then, the polarization voltage is fitted using the calculation formula for the discharge period. This polarization voltage data is then used as input data for the stand period calculation process, and the stand period calculation formula is applied again. Through segmented calculations, the parameters of the battery's equivalent circuit model are finally identified. However, because the stand period calculation relies on data calculated using the discharge period formula, errors generated during discharge period calculations accumulate in the stand period calculations, leading to a large cumulative error and consequently, low accuracy of the finally identified model parameters.

[0065] Therefore, this application provides a battery model parameter identification method, apparatus, and engineering vehicle, which can obtain more accurate model parameters, thereby improving the accuracy of the battery equivalent circuit model. The battery model parameter identification method, apparatus, and engineering vehicle are described in detail below.

[0066] Figure 1 This is a flowchart illustrating a battery model parameter identification method provided as an exemplary embodiment of this application. Figure 1 As shown, the battery model parameter identification method provided in this application embodiment may include:

[0067] S210: Obtain the correspondence between the battery's state of charge and the battery's open-circuit voltage under preset operating conditions.

[0068] Specifically, the preset operating conditions can include multiple test cycles, each including a discharge phase and a resting phase of the battery under different states of charge. In other words, within the same test cycle, the battery has both a discharge phase and a resting phase. By repeatedly adjusting the battery's state of charge and cycling through multiple test cycles, the correspondence between the battery's state of charge and its open-circuit voltage can be obtained.

[0069] It should be noted that the open-circuit voltage of a battery can be understood as the voltage difference between the positive and negative terminals of the battery when it is not in operation. The open-circuit voltage can be measured after the battery has been left to rest during each test cycle.

[0070] It should be noted that by analyzing the relationship between the battery's state of charge (SOC) and its open-circuit voltage, the corresponding open-circuit voltage values ​​for different SOC states can be determined. This relationship can be represented by a curve, displayed through multiple distribution points, or presented using a data matrix, etc.

[0071] S220: The target relation is calculated based on the preset battery equivalent circuit model.

[0072] Figure 2 A schematic diagram of the structure of a preset battery equivalent circuit model provided for an exemplary embodiment of this application. Figure 2 U in oc It can characterize the open-circuit voltage of a battery; Figure 2 Middle I L It can characterize the total current in a pre-defined battery equivalent circuit model; Figure 2 R0 can characterize the ohmic internal resistance of the battery; Figure 2 The preset battery equivalent circuit model includes multiple series RC combinations, each of which may include capacitors connected in parallel. Figure 2 C in pa and C pc ) and polarization resistance ( Figure 2 R in pa and R pc The capacitor reflects the brief reaction process of the battery during charging and discharging. The current through the polarization resistor can be understood as the polarization current in the embodiments of this application. The number of RC combinations can be one, two, three, etc., and the embodiments of this application are described with two RC combinations.

[0073] Specifically, the target relationship can include the relationship between the total current in the preset battery equivalent circuit model and the polarization current in the preset battery equivalent circuit model. The total current can be measured using an ammeter. Within the same test cycle, whether in the discharge phase or the resting phase, the total current can be actually measured using the ammeter, and the accuracy of this total current measurement is not affected by discharge or resting. Therefore, in application, the relationship between the total current and the polarization current can simultaneously utilize the total current data from both the discharge and resting phases. In other words, when applying this relationship, segmented calculations are unnecessary; the total current data from both the discharge and resting phases can be used simultaneously as input data for calculation, eliminating the accumulated error in the segmented calculation process and improving the accuracy of the final calculation result.

[0074] S230: Run the preset battery equivalent circuit model to obtain the total current and terminal voltage in the preset battery equivalent circuit model during different test cycles.

[0075] like Figure 2 As shown, Figure 2 U in L The terminal voltage in the preset battery equivalent circuit model can be characterized. In the embodiments of this application, the terminal voltage can be understood as the closed-circuit terminal voltage, that is, the work done by the electric field force to move a unit positive charge from the positive terminal of the power supply to the negative terminal of the power supply along the external circuit. During the operation of the preset battery equivalent battery model, the terminal voltage can be measured by a voltmeter.

[0076] It should be understood that, in conjunction with the aforementioned introduction to total current, during the operation of the preset battery equivalent circuit model, the total current and terminal voltage can be measured using an ammeter and a voltmeter at different test cycles.

[0077] S240: Based on the correspondence between state of charge and open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, the target parameters in the preset battery equivalent circuit model under different states of charge are calculated.

[0078] Specifically, step S210 yields the correspondence between the state of charge and the circuit voltage. The target relationship can include the relationship between the terminal voltage, open-circuit voltage, total current, and polarization current of the preset battery equivalent circuit model, as well as the relationship between the total current and the polarization current. Then, combining Kirchhoff's laws from related technologies and the total current and terminal voltage measured over multiple test cycles, the target parameters of the preset battery equivalent circuit model can be calculated. Since the target relationship can simultaneously utilize the total current data from both the discharge and resting phases during application, segmented calculations are unnecessary when applying the relationship between the total current and the polarization current. Instead, the total current data from both the discharge and resting phases can be used simultaneously as input data, eliminating accumulated errors during segmented calculations and improving the accuracy of the final calculation result.

[0079] In one embodiment, such as Figure 2 As shown, according to Kirchhoff's laws, the following relationship can be obtained:

[0080]

[0081] Based on the preset battery equivalent circuit model, the target relational expression can include:

[0082]

[0083]

[0084] Therefore, 'i' in the above formula can represent different sampling points in the test cycle. A sampling point can be understood as the time node in the test cycle when the total current and terminal voltage are acquired. The meanings of other parameters can be found in the previous sections. Substituting the total current and terminal voltage measured in different test cycles, the target parameters R0 and R can be calculated. pa R pc C pa C pc It should be understood that when substituting the total current and terminal voltage data, based on the above target relationship, segmented calculations are not required, thus eliminating accumulated errors and improving the accuracy of the calculated target parameters.

[0085] The battery model parameter identification method provided in this application obtains the correspondence between the battery's state of charge and open-circuit voltage under preset operating conditions. Then, based on a preset battery equivalent circuit model, it calculates the target relationship. The preset battery equivalent circuit model is then run to obtain the total current and terminal voltage in the preset battery equivalent circuit during different test cycles. Based on the correspondence between the state of charge and open-circuit voltage, the target relationship, the total current during multiple test cycles, and the terminal voltage during multiple test cycles, the target parameters in the preset battery equivalent circuit model under different state of charge are calculated. Since the total current can be actually measured by an ammeter during both the discharge and resting phases in the same test cycle, the accuracy of this total current measurement is not affected by discharge or resting. Therefore, when applying the target relationship for calculation, the total current data from both the discharge and resting phases can be used simultaneously without segmented calculation. This eliminates the accumulated error during segmented calculation and improves the accuracy of the final calculated target parameters.

[0086] Figure 3 This is a schematic flowchart illustrating the correspondence between the state of charge of a battery and its open-circuit voltage under preset operating conditions, provided as an exemplary embodiment of this application. Figure 3 As shown, step S210 may include:

[0087] S211: Controls the battery to discharge and rest under different states of charge.

[0088] Specifically, the discharge process can be carried out using pulse discharge, and the period of the pulse discharge can be selected as 30s, 40s, etc.

[0089] Specifically, the purpose of controlling the battery to rest is to allow the battery to reach an electrochemical and thermal equilibrium state, which makes it easier to obtain the open-circuit voltage during the resting period.

[0090] It should be understood that the battery needs to be controlled to discharge and rest during each test cycle.

[0091] S212: Obtain the open-circuit voltage of the battery after it has been left to rest under different states of charge.

[0092] Specifically, the battery is left to rest under different states of charge, and the open-circuit voltage after resting is measured. The measured open-circuit voltage corresponds one-to-one with the battery's state of charge.

[0093] S213: Based on different states of charge and the corresponding open-circuit voltage after resting, obtain the correspondence between the state of charge of the battery and the open-circuit voltage of the battery.

[0094] Specifically, by summarizing the open-circuit voltage data corresponding to different states of charge and forming a data matrix or distribution curve, the correspondence between the battery's state of charge and its open-circuit voltage can be obtained.

[0095] Figure 4 This is a schematic diagram illustrating a process for controlling the discharge and resting of a battery under different states of charge, provided as an exemplary embodiment of this application. Figure 4 As shown, step S211 may include:

[0096] S2111: Controls the battery to discharge under its current state of charge.

[0097] S2112: Controls the first preset time for the battery to remain stationary.

[0098] Specifically, controlling the battery to rest for a first preset time can stabilize the battery's state after discharge, ensuring that the battery's state of charge is within a stable range, which facilitates subsequent adjustment of the battery's state of charge based on the current state of charge.

[0099] In one embodiment, the first preset duration can be selected as 5 minutes, 10 minutes, etc.

[0100] It should be understood that the first preset duration can be set according to the actual situation, and this application does not make a specific limitation on the first preset duration.

[0101] S2113: Adjust the state of charge of the battery.

[0102] S2114: Control the battery to remain stationary for a second preset time after adjusting its state of charge.

[0103] Specifically, the second preset duration is generally a relatively long period of time. When the battery is left to stand in the adjusted charged state for the second preset duration, it can reach an electrochemical and thermal equilibrium state. In this state, the open-circuit voltage of the battery can be measured more accurately.

[0104] In one embodiment, the second preset duration can be selected as 3 hours, 4 hours, etc.

[0105] It should be understood that the second preset duration can be set according to the actual situation, and this application does not make a specific limitation on the second preset duration.

[0106] In one embodiment, the first preset duration may be greater than the second preset duration; or, the first preset duration may be less than the second preset duration; or, the first preset duration may be equal to the second preset duration.

[0107] In one embodiment, steps S2111, S2112, S2113 and S2114 can be executed cyclically. Each time the cycle is executed, the state of charge can be adjusted once, and then a set of corresponding data between the state of charge and the open circuit voltage can be obtained until the state of charge is 0%, at which point the cycle stops.

[0108] Figure 5 This is a schematic flowchart illustrating the correspondence between the state of charge (SBC) and the open-circuit voltage of a battery based on different SBCs and their corresponding open-circuit voltages after resting, as provided in an exemplary embodiment of this application. Figure 5 As shown, step S213 may include:

[0109] S2131: Based on different states of charge and the corresponding open-circuit voltage after resting, obtain multiple distribution points of the states of charge and open-circuit voltage.

[0110] Specifically, with the state of charge as the horizontal axis and the open-circuit voltage as the vertical axis, multiple distribution points can be obtained based on their corresponding relationships. Each distribution point represents the open-circuit voltage corresponding to a specific state of charge.

[0111] S2132: In different state-of-charge intervals, add additional target points at multiple distribution points with different state-of-charge interval values.

[0112] S2133: Based on multiple distribution points and multiple target points, a relationship curve characterizing the state of charge of the battery and the open-circuit voltage of the battery is obtained by fitting.

[0113] Specifically, after obtaining multiple distribution points, in order to improve the accuracy of the relationship curve characterizing the correspondence between the state of charge and the open-circuit voltage, additional target points can be added between the multiple distribution points to make the fitted relationship curve smoother and more accurately reflect the relationship between the state of charge and the open-circuit voltage.

[0114] It should be noted that due to the inherent characteristics of batteries, the rate of change of open-circuit voltage with respect to the state of charge (SOC) varies across different SOC ranges. Therefore, the SOC interval used when adding additional target points across multiple distribution points will differ. Generally, the greater the rate of change of open-circuit voltage with respect to SOC, the smaller the SOC interval should be. This makes it easier to connect two adjacent distribution points that are far apart by adding more target points using a smooth curve, resulting in a curve that more accurately reflects the relationship between SOC and open-circuit voltage. Conversely, the smaller the rate of change of open-circuit voltage with respect to SOC, the smaller the change in distance between two adjacent distribution points. Therefore, a larger SOC interval should be used. This ensures that adjacent distribution points can be connected by a smooth curve while also appropriately reducing the number of target points added, effectively improving work efficiency.

[0115] Figure 6 This is a schematic diagram illustrating a process for adding additional target points at multiple distribution points within different state-of-charge intervals, as provided in an exemplary embodiment of this application. Figure 6 As shown, step S2132 may include:

[0116] S21321: Within the first state of charge interval, add additional target points within the first state of charge interval by the first state of charge interval value.

[0117] S21322: Within the second state of charge interval, add additional target points within the second state of charge interval by the second state of charge interval value.

[0118] S21323: Within the third state of charge interval, add additional target points within the third state of charge interval using the third state of charge interval value.

[0119] Specifically, in this embodiment of the application, the battery is a lithium iron phosphate battery. Due to the characteristics of lithium iron phosphate batteries, the open-circuit voltage plateau period is relatively long and slow, and the open-circuit voltage plateau is concentrated in the middle range of the state of charge (the aforementioned second state of charge range). Therefore, more target points are generally added in the low-end range of the state of charge (the aforementioned first state of charge range) and the high-end range (the aforementioned third state of charge range), while fewer target points are added in the middle range.

[0120] Specifically, any state of charge (SOC) value within the second SOC interval is greater than the maximum SOC value within the first SOC interval, and any SOC value within the third SOC interval is greater than the maximum SOC value within the second SOC interval. The first, second, and third SOC intervals are consecutive intervals arranged in ascending order of magnitude. Therefore, to form a relatively accurate smooth curve within the regions corresponding to the first and third SOC intervals, more target points can be added within these regions using smaller first and third SOC interval values, respectively. Conversely, to improve efficiency, while ensuring a smooth curve can be formed within the region corresponding to the second SOC interval, fewer target points can be added using a larger second SOC interval value. It can be inferred that the first, second, and third SOC interval values ​​should satisfy the following conditions: the second SOC interval value is greater than the first SOC interval value; and the third SOC interval value is less than the second SOC interval value.

[0121] In one embodiment, the first state-of-charge interval value and the third state-of-charge interval value may be equal or unequal.

[0122] In one embodiment, the first state of charge interval value and the third state of charge interval value are equal and both are 2.5%, and the second state of charge interval value is 5%.

[0123] In one embodiment, the first state of charge range can be a state of charge range of 0-20%; the second state of charge range can be a state of charge range of 20%-80%; and the third state of charge range can be a state of charge range of 80%-100%.

[0124] Figure 7 This is a flowchart illustrating a battery model parameter identification method provided as another exemplary embodiment of this application. Figure 7 As shown, after step S240, the battery model parameter identification method may further include:

[0125] S250: Based on the target parameters, run the preset battery equivalent circuit model to obtain the fitted terminal voltage under the target state of charge.

[0126] Specifically, after executing step S240, multiple target parameters in the preset battery equivalent circuit model can be calculated. The multiple target parameters are substituted into the preset battery equivalent circuit model, and the preset battery equivalent circuit model is run. Based on the aforementioned target relationship and Kirchhoff's laws in related technologies, the fitted terminal voltage under the target state of charge can be output.

[0127] It should be understood that the target state of charge can be set according to the actual situation, and this application does not make specific limitations on the target state of charge.

[0128] S260: Obtain the actual terminal voltage of the battery under the target state of charge.

[0129] Specifically, the battery's state of charge is adjusted to the target state of charge, and then the actual terminal voltage of the battery under the target state of charge can be measured using a voltmeter.

[0130] S270: Outputs the fitting accuracy result based on the fitted terminal voltage and the actual terminal voltage.

[0131] Specifically, based on the fitted terminal voltage obtained after executing step S250, the variation curve of the fitted terminal voltage within a preset time period can be obtained; based on the actual terminal voltage obtained after executing step S260, the variation curve of the actual terminal voltage within a preset time period can be obtained; then, fitting analysis is performed on the variation curves of the fitted terminal voltage and the actual terminal voltage within the preset time period to output the fitting accuracy result. Thus, based on the fitting accuracy result, the accuracy of the target parameter obtained in step S240 can be easily analyzed. Generally, if the output fitting accuracy result indicates a high fitting accuracy, that is, the values ​​and trends of the fitted terminal voltage and the actual terminal voltage are relatively close, then the accuracy of the target parameter obtained in step S240 can be considered high.

[0132] Figure 8 This is a flowchart illustrating a battery model parameter identification method provided as another exemplary embodiment of this application. Figure 8 As shown, after step S270, the battery model parameter identification method further includes:

[0133] S280: If the voltage difference represented by the fitting accuracy result is less than or equal to the voltage threshold, then output a signal that retains the target parameters.

[0134] Specifically, if the voltage difference represented by the fitting accuracy result is less than or equal to the voltage threshold, then it can be considered that the difference between the fitted terminal voltage and the actual terminal voltage is not large, and the accuracy of the output fitting accuracy result is high. Therefore, a signal that retains the target parameters can be output and the target parameters obtained in step S240 can be stored.

[0135] In one embodiment, the voltage threshold can be set according to the actual situation, such as 2mV, 2.5mV, etc. This application does not specifically limit the voltage threshold.

[0136] S290: If the voltage difference represented by the fitting accuracy result is greater than the voltage threshold, then increase the number of sampling points in each test cycle.

[0137] Specifically, if the voltage difference represented by the fitting accuracy result is greater than the voltage threshold, then it can be considered that the difference between the fitted terminal voltage and the actual terminal voltage is large, and the accuracy of the target parameter needs to be improved. To this end, the number of sampling points in each test cycle can be increased. A sampling point can be understood as the time node for acquiring the total current and terminal voltage in the test cycle. Increasing the number of sampling points can increase the amount of sample data of the total current and terminal voltage acquired subsequently, which is beneficial to improving the accuracy of the target parameter calculated subsequently.

[0138] In one embodiment, the number of sampling points added in each test cycle can be set according to the actual situation, for example, 100 or 200 points can be added. This application does not make a specific limit on the number of sampling points added in each test cycle.

[0139] S300: Run the preset battery equivalent circuit model again to obtain the total current and terminal voltage in the preset battery equivalent circuit model during the test cycle after adding sampling points.

[0140] S310: Based on the correspondence between state of charge and open-circuit voltage, the target formula, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, new target parameters in the preset battery equivalent circuit model are calculated under different states of charge.

[0141] Specifically, the execution process of step S300 can refer to the execution process of step S230, and the execution process of step S310 can refer to the execution process of step S240.

[0142] In one embodiment, steps S290, S300 and S310 can be repeated multiple times to gradually improve the accuracy of the target parameters, so that the voltage difference represented by the fitting accuracy result meets the requirement of being less than or equal to the voltage threshold.

[0143] Figure 9 This is a structural block diagram of a battery model parameter identification device provided as an exemplary embodiment of this application. Figure 9As shown, the battery model parameter identification device 400 provided in this application embodiment may include: a first acquisition module 410, configured to acquire the correspondence between the state of charge of the battery and the open-circuit voltage of the battery under a preset operating condition; wherein, the preset operating condition includes multiple test cycles, and different test cycles include the discharge stage and the resting stage of the battery under different states of charge; a first calculation module 420, configured to calculate the target relationship based on a preset battery equivalent circuit model; wherein, the target relationship includes the relationship between the total current in the preset battery equivalent circuit model and the polarization current in the preset battery equivalent circuit model; a first measurement module 430, configured to run the preset battery equivalent circuit model and acquire the total current and terminal voltage in the preset battery equivalent circuit model within different test cycles; and a second calculation module 440, configured to calculate the target parameters in the preset battery equivalent circuit model under different states of charge based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current within multiple test cycles, and the terminal voltage within multiple test cycles.

[0144] The battery model parameter identification device provided in this application obtains the correspondence between the battery's state of charge and open-circuit voltage under preset operating conditions. Then, based on a preset battery equivalent circuit model, it calculates the target relationship. The device then runs the preset battery equivalent circuit model to obtain the total current and terminal voltage in the preset battery equivalent circuit during different test cycles. Finally, based on the correspondence between the state of charge and open-circuit voltage, the target relationship, the total current during multiple test cycles, and the terminal voltage during multiple test cycles, it calculates the target parameters in the preset battery equivalent circuit model under different state of charge. Since the total current can be actually measured by an ammeter during both the discharge and resting phases in the same test cycle, the accuracy of this total current measurement is not affected by discharge or resting. Therefore, when applying the target relationship for calculation, the total current data from both the discharge and resting phases can be used simultaneously without segmented calculation. This eliminates the accumulated error during segmented calculation and improves the accuracy of the final calculated target parameters.

[0145] Figure 10 A structural block diagram of a battery model parameter identification device provided as another exemplary embodiment of this application. (See diagram below.) Figure 10 As shown, in one embodiment, the first acquisition module 410 may include a first control module 411 configured to control the battery to discharge and rest under different states of charge; a second acquisition module 412 configured to acquire the open-circuit voltage of the battery after resting under different states of charge; and a relationship generation module 413 configured to obtain the correspondence between the state of charge of the battery and the open-circuit voltage of the battery based on the different states of charge and the corresponding open-circuit voltage after resting.

[0146] like Figure 10 As shown, in one embodiment, the first control module 411 may include a discharge module 4111 configured to control the battery to discharge in the current state of charge; a first resting module 4112 configured to control the battery to rest for a first preset time; an adjustment module 4113 configured to adjust the state of charge of the battery; and a second resting module 4114 configured to control the battery to rest in the adjusted state of charge for a second preset time; wherein the second preset time is longer than the first preset time.

[0147] like Figure 10 As shown, in one embodiment, the relationship generation module 413 may include a distribution module 4131, configured to obtain multiple distribution points of state of charge and open circuit voltage based on different states of charge and corresponding open circuit voltages after resting; a target point addition module 4132, configured to add additional target points to the multiple distribution points in different state of charge intervals with different state of charge interval values; and a fitting module 4133, configured to fit a relationship curve characterizing the correspondence between the state of charge and the open circuit voltage of the battery based on the multiple distribution points and multiple target points.

[0148] like Figure 10 As shown, in one embodiment, the target point adding module 4132 may include a first adding module 41321, configured to add additional target points within a first state of charge interval at a first state of charge interval; a second adding module 41322, configured to add additional target points within a second state of charge interval at a second state of charge interval; wherein any state of charge value within the second state of charge interval is greater than the maximum state of charge value within the first state of charge interval; the second state of charge interval is greater than the first state of charge interval; and a third adding module 41323, configured to add additional target points within a third state of charge interval at a third state of charge interval; wherein any state of charge value within the third state of charge interval is greater than the maximum state of charge value within the second state of charge interval; the third state of charge interval is less than the second state of charge interval.

[0149] like Figure 10 As shown, in one embodiment, the battery model parameter identification device 400 may include a third acquisition module 450, configured to run a preset battery equivalent circuit model according to the target parameters to obtain the fitted terminal voltage under the target state of charge; a fourth acquisition module 460, configured to acquire the actual terminal voltage of the battery under the target state of charge; and a first output module 470, configured to output the fitting accuracy result according to the fitted terminal voltage and the actual terminal voltage.

[0150] like Figure 10 As shown, in one embodiment, the battery model parameter identification device 400 may include a second output module 480 configured to output a signal retaining the target parameters if the voltage difference represented by the fitting accuracy result is less than or equal to a voltage threshold; an adjustment module 490 configured to increase the number of sampling points in each test cycle if the voltage difference represented by the fitting accuracy result is greater than the voltage threshold; a second measurement module 500 configured to run the preset battery equivalent circuit model again to obtain the total current and terminal voltage in the preset battery equivalent circuit model within the test cycle after increasing the sampling points; and a third calculation module 510 configured to calculate new target parameters in the preset battery equivalent circuit model under different states of charge based on the correspondence between the state of charge and open circuit voltage, the target relationship, the total current within multiple test cycles, and the terminal voltage within multiple test cycles.

[0151] Figure 11 A structural block diagram of an engineering vehicle provided for an exemplary embodiment of this application. (See diagram below.) Figure 11 As shown, the engineering vehicle 600 provided in this application embodiment may include: a vehicle body 610; and a battery model parameter identification device 400 as described above, which is disposed on the vehicle body 610.

[0152] In one embodiment, the engineering vehicle 600 may include an excavator, a crane, a pump truck, etc.

[0153] The engineering vehicle 600 provided in this application embodiment has all the functions of its battery model parameter identification device 400. It obtains the correspondence between the battery's state of charge and open-circuit voltage under preset working conditions, then calculates the target relationship based on the preset battery equivalent circuit model, and then runs the preset battery equivalent circuit model to obtain the total current and terminal voltage in the preset battery equivalent circuit in different test cycles. Then, based on the correspondence between the state of charge and open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, it calculates the target parameters in the preset battery equivalent circuit model under different state of charge. Since the total current can be actually measured by an ammeter in the same test cycle, whether in the discharge stage or the resting stage, the accuracy of the total current measurement is not affected by discharge or resting. Therefore, when applying the target relationship for calculation, the total current data of the discharge stage and the resting stage can be used simultaneously without segmented calculation. The total current data of the discharge stage and the resting stage are used as input data for calculation at the same time, eliminating the cumulative error in the segmented calculation process and improving the accuracy of the final calculated target parameters.

[0154] Figure 12 A structural block diagram of an engineering vehicle provided for another exemplary embodiment of this application. (See diagram below.) Figure 12As shown, the engineering vehicle 800 provided in this application embodiment may include: a vehicle body 810; and an electronic device 820 disposed on the vehicle body 810. The electronic device 820 is configured to perform the battery model parameter identification method as described above.

[0155] In one embodiment, the engineering vehicle 800 may include an excavator, a crane, a pump truck, etc.

[0156] The engineering vehicle 800 provided in this application embodiment obtains the correspondence between the state of charge (SBC) and open-circuit voltage of the battery under preset operating conditions. Then, based on a preset battery equivalent circuit model, it calculates the target relationship. The preset battery equivalent circuit model is then run to obtain the total current and terminal voltage in the preset battery equivalent circuit during different test cycles. Based on the correspondence between SBC and open-circuit voltage, the target relationship, the total current during multiple test cycles, and the terminal voltage during multiple test cycles, the target parameters in the preset battery equivalent circuit model under different SBC states are calculated. Since the total current can be actually measured by an ammeter during both the discharge and resting phases in the same test cycle, the accuracy of this total current measurement is not affected by discharge or resting. Therefore, when applying the target relationship for calculation, the total current data from both the discharge and resting phases can be used simultaneously without segmented calculation. The total current data from both the discharge and resting phases are used as input data for calculation simultaneously, eliminating the accumulated error in the segmented calculation process and improving the accuracy of the final calculated target parameters.

[0157] Figure 13 This is a structural block diagram of an electronic device provided as an exemplary embodiment of this application. (See diagram below.) Figure 13 As shown, the electronic device 820 can be either or both of the first device and the second device, or a standalone device independent of them, which can communicate with the first device and the second device to receive the collected input signals from them.

[0158] like Figure 13 As shown, the electronic device 820 includes one or more processors 821 and memory 822.

[0159] The processor 821 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device 820 to perform desired functions.

[0160] The memory 822 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 821 may execute the program instructions to implement the control methods and / or other desired functions of the various embodiments of this application described above. Various contents such as input signals, signal components, and noise components may also be stored in the computer-readable storage medium.

[0161] In one example, the electronic device 820 may also include an input device 823 and an output device 8204, which are interconnected via a bus system and / or other forms of connection mechanism (not shown).

[0162] When the controller is a standalone device, the input device 823 can be a communication network connector for receiving the acquired input signals from the first device and the second device.

[0163] In addition, the input device 823 may also include, for example, a keyboard, a mouse, etc.

[0164] The output device 8204 can output various information to the outside, including determined distance information, direction information, etc. The output device 8204 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0165] Of course, for the sake of simplicity, Figure 13 Only some of the components of the electronic device 820 relevant to this application are shown in this illustration; components such as buses, input / output interfaces, etc., are omitted. In addition, the electronic device 820 may include any other suitable components depending on the specific application.

[0166] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0167] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0168] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0169] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0170] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0171] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0172] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for identifying battery model parameters, characterized in that, include: Obtain the correspondence between the state of charge of the battery and the open-circuit voltage of the battery under preset operating conditions; wherein, the preset operating conditions include multiple test cycles, and different test cycles include the discharge stage and the resting stage of the battery under different states of charge; Based on the preset battery equivalent circuit model, the target relationship is calculated; wherein, the target relationship includes the relationship between the total current in the preset battery equivalent circuit model and the polarization current in the preset battery equivalent circuit model. By running the preset battery equivalent circuit model, the total current and terminal voltage in the preset battery equivalent circuit model are obtained during different test cycles; and Based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, the target parameters in the preset battery equivalent circuit model under different states of charge are calculated.

2. The battery model parameter identification method according to claim 1, characterized in that, The process of obtaining the correspondence between the battery's state of charge and its open-circuit voltage under preset operating conditions includes: Control the battery to discharge and rest under different states of charge; Obtain the open-circuit voltage of the battery after it has been left to rest under different states of charge; and Based on the different states of charge and the corresponding open-circuit voltage after resting, the correspondence between the state of charge of the battery and the open-circuit voltage of the battery is obtained.

3. The battery model parameter identification method according to claim 2, characterized in that, The control of the battery to discharge and rest under different states of charge includes: Control the battery to discharge under its current state of charge; Control the battery to remain stationary for a first preset time; Adjusting the state of charge of the battery; and The battery is controlled to remain stationary for a second preset time under the adjusted state of charge.

4. The battery model parameter identification method according to claim 2, characterized in that, The step of obtaining the correspondence between the state of charge of the battery and the open-circuit voltage of the battery based on different states of charge and the corresponding open-circuit voltage after resting includes: Based on the different states of charge and the corresponding open-circuit voltage after resting, multiple distribution points of the states of charge and the open-circuit voltage are obtained; Within different state-of-charge intervals, additional target points are added to the multiple distribution points at different state-of-charge intervals; and Based on multiple distribution points and multiple target points, a relationship curve characterizing the correspondence between the state of charge of the battery and the open-circuit voltage of the battery is obtained by fitting.

5. The battery model parameter identification method according to claim 4, characterized in that, The step of adding additional target points among the multiple distribution points within different state-of-charge intervals includes: Within the first state of charge interval, additional target points are added within the first state of charge interval by a first state of charge interval value; Within the second state of charge interval, additional target points are added at second state of charge intervals; wherein any state of charge value within the second state of charge interval is greater than the maximum state of charge value within the first state of charge interval; and the second state of charge interval is greater than the first state of charge interval; and... Within the third state of charge interval, additional target points are added within the third state of charge interval by a third state of charge interval value; wherein any state of charge value within the third state of charge interval is greater than the maximum state of charge value within the second state of charge interval; and the third state of charge interval value is less than the second state of charge interval value.

6. The battery model parameter identification method according to claim 1, characterized in that, After calculating the target parameters in the preset battery equivalent circuit model under different states of charge, the battery model parameter identification method further includes: Based on the target parameters, the preset battery equivalent circuit model is run to obtain the fitted terminal voltage under the target state of charge. Obtain the actual terminal voltage of the battery under the target state of charge; and Based on the fitted terminal voltage and the actual terminal voltage, the fitting accuracy result is output.

7. The battery model parameter identification method according to claim 6, characterized in that, Following the output fitting accuracy result, the battery model parameter identification method further includes: If the voltage difference represented by the fitting accuracy result is less than or equal to the voltage threshold, then output a signal that retains the target parameters; or If the voltage difference represented by the fitting accuracy result is greater than the voltage threshold, then the number of sampling points in each test cycle is increased; wherein, the sampling point represents the time node for acquiring the total current and the terminal voltage; Run the preset battery equivalent circuit model again to obtain the total current and terminal voltage in the preset battery equivalent circuit model during the test period after adding the sampling points; Based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles, new target parameters in the preset battery equivalent circuit model under different states of charge are calculated.

8. A battery model parameter identification device, characterized in that, include: The first acquisition module is configured to acquire the correspondence between the state of charge of the battery and the open-circuit voltage of the battery under preset operating conditions; wherein, the preset operating conditions include multiple test cycles, and different test cycles include the discharge stage and the resting stage of the battery under different states of charge; The first calculation module is configured to calculate a target relation based on a preset battery equivalent circuit model; wherein the target relation includes the relationship between the total current in the preset battery equivalent circuit model and the polarization current in the preset battery equivalent circuit model. The first measurement module is configured to run the preset battery equivalent circuit model to obtain the total current and terminal voltage in the preset battery equivalent circuit model during different test cycles; and The second calculation module is configured to calculate the target parameters in the preset battery equivalent circuit model under different states of charge based on the correspondence between the state of charge and the open-circuit voltage, the target relationship, the total current in multiple test cycles, and the terminal voltage in multiple test cycles.

9. An engineering vehicle, characterized in that, include: Vehicle body; The battery model parameter identification device as described in claim 8, wherein the battery model parameter identification device is disposed on the vehicle body.

10. An engineering vehicle, characterized in that, include: Vehicle body; An electronic device, disposed on the vehicle body, is configured to perform the battery model parameter identification method as described in any one of claims 1 to 7.

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