Vehicle end and remote processing unit, battery model updating method and electric vehicle

Abstract

The invention relates to a vehicle end and remote processing unit, a battery model updating method and an electric vehicle, and belongs to the technical field of electric vehicle battery systems. According to the method, the vehicle-end BMS battery model and the battery twinborn model in the remote monitoring platform are used for calculating the battery operation data, outputting results and comparing the results, and whether the vehicle-end BMS battery model has errors or not is judged, so that parameters of the vehicle-end BMS battery model can be updated in time, the calculation result of the vehicle-end BMS battery model is more accurate, and the calculation efficiency of the vehicle-end BMS battery model is improved. And meanwhile, after the parameters of the battery twinborn model in the remote monitoring platform are updated, the vehicle-end BMS battery model is continuously monitored, so that high-precision safety management of the vehicle-end battery is realized.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle battery system technology, specifically involving vehicle-side and remote processing units, battery model update methods, and electric vehicles. Background Technology

[0002] Electric vehicles use electric motors as drive units and are powered by onboard batteries. To ensure the efficiency and safety of battery use, it is necessary to control and monitor the battery status.

[0003] Currently, electric vehicle batteries are typically monitored and managed using a Battery Management System (BMS). However, due to the inherent hardware limitations of the BMS, the accuracy of the battery model calculations within the vehicle can be low, especially when data analysis and modeling involve significant computational demands. For instance, when using a parameter identification method (i.e., offline identification) to identify battery model parameters for a real vehicle's battery and then embedding these parameters into the vehicle's BMS as initial identification parameters for the battery model, the battery characteristics change as the vehicle operates. This leads to increasing errors in the State of Charge (SOC) estimation by the vehicle's BMS, resulting in inaccurate battery management. Summary of the Invention

[0004] The purpose of this invention is to provide a vehicle-side and remote processing unit, a battery model update method, and an electric vehicle to solve the problem of low accuracy in vehicle-side model calculation results.

[0005] To address the aforementioned technical problems, this invention provides a method for updating a vehicle battery model. The method involves inputting actual battery operating data into both the vehicle-side BMS battery model running within the vehicle's battery management system and the remote monitoring platform battery twin model running on a remote monitoring platform. The output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model are compared. If the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the remote monitoring platform uses the actual battery operating data to re-identify the battery parameters and updates the battery parameters of both the vehicle-side BMS battery model and the remote monitoring platform battery twin model using the re-identified battery parameters.

[0006] Furthermore, the difference refers to the absolute value of the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model, and the difference threshold is set as the set difference threshold.

[0007] Furthermore, the vehicle-side BMS battery model can be an equivalent circuit model, an electrochemical model, a mathematical model, a thermal model, or an aging model. Specifically, the equivalent circuit model is a model that uses circuitry to simulate battery operation; the electrochemical model is a model that uses the principles of chemical reactions to simulate the battery; the mathematical model is a model that uses mathematical theories and experience to simulate battery characteristics; the thermal model is a model that relies on the relationship between internal electrochemical reactions and heat during charging and discharging; and the aging model is a model that is based on the degradation of battery capacity and power.

[0008] Furthermore, the equivalent circuit model can be an Ohmic internal resistance model, a Thevenin model, a PNGV model, or a higher-order RC model.

[0009] Furthermore, when the vehicle-side BMS battery model is an Ohmic internal resistance model, the battery parameters include the internal resistance and voltage source voltage in the model; when the vehicle-side BMS battery model is a Thevenin model, the battery parameters include the internal resistance, voltage source voltage, resistance values ​​of resistors, and capacitance values ​​of capacitors; when the vehicle-side BMS battery model is a PNGV model, the battery parameters include the internal resistance, voltage source voltage, resistance values ​​of resistors, and capacitance values ​​of each capacitor; when the vehicle-side BMS battery model is a high-order RC model, the battery parameters include the internal resistance, voltage source voltage, resistance values ​​of each resistor, and capacitance values ​​of each capacitor.

[0010] Furthermore, when the vehicle-side BMS battery model is an equivalent circuit model, the method for identifying battery parameters is as follows: initial values ​​are assigned to the battery parameters of the model and upper and lower limits are defined; the operating current is input to the model to obtain the corresponding operating voltage; the operating voltage is compared with the actual voltage; the battery parameters of the model are corrected so that the difference between the operating voltage and the actual voltage is less than the set difference threshold; when the difference between the operating voltage and the actual voltage is less than the set difference threshold, the battery parameters in the model are the identified battery parameters.

[0011] Furthermore, when the vehicle-side BMS battery model is an equivalent circuit model, the actual battery operating data includes battery current, temperature, and voltage.

[0012] To address the aforementioned technical problems, the present invention also provides a vehicle-side processing unit. The vehicle-side processing unit is used to input actual battery operating data into the vehicle-side BMS battery model, and to update the battery parameters of the vehicle-side BMS battery model using the battery parameters re-identified by the remote monitoring platform when the difference between the output values ​​of the vehicle-side BMS battery model and the battery twin model of the remote monitoring platform exceeds a set difference threshold.

[0013] To address the aforementioned technical problems, the present invention also provides a remote processing unit. The remote processing unit is used to input actual battery operating data into the battery twin model of the remote monitoring platform running on the remote monitoring platform. When the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the remote processing unit uses the actual battery operating data to re-identify the battery parameters and updates the battery parameters of the remote monitoring platform battery twin model using the re-identified battery parameters.

[0014] To address the aforementioned technical problems, the present invention also provides an electric vehicle, including a battery information acquisition unit and a vehicle-side processing unit; the battery information acquisition unit is used to acquire actual battery operating data; the vehicle-side processing unit is used to input the actual battery operating data into the vehicle-side BMS battery model, and when the difference between the output values ​​of the vehicle-side BMS battery model and the battery twin model of the remote monitoring platform exceeds a set difference threshold, it uses the battery parameters re-identified by the remote monitoring platform to update the battery parameters of the vehicle-side BMS battery model.

[0015] The beneficial effects of the above technical solution are as follows: This invention is an improved invention. By using the vehicle-side BMS battery model and the battery twin model in the remote monitoring platform to calculate and output the battery operation data and compare the results, it can determine whether there are errors in the vehicle-side BMS battery model. This allows the parameters of the vehicle-side BMS battery model to be updated in a timely manner, making the calculation results of the vehicle-side BMS battery model more accurate. At the same time, after updating the parameters of the battery twin model in the remote monitoring platform, the vehicle-side BMS battery model can continue to be monitored. Attached Figure Description

[0016] Figure 1 This is an architectural diagram of an electric vehicle embodiment of the present invention;

[0017] Figure 2 This is a flowchart of an electric vehicle embodiment of the present invention;

[0018] Figure 3 This is a flowchart illustrating the parameter identification process of an electric vehicle embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of the ohmic internal resistance model of an electric vehicle embodiment of the present invention;

[0020] Figure 5 This is a Thevenin model diagram of an electric vehicle embodiment of the present invention;

[0021] Figure 6 This is a PNGV model diagram of an electric vehicle embodiment of the present invention;

[0022] Figure 7This is a high-order RC model diagram of an electric vehicle embodiment of the present invention. Detailed Implementation

[0023] The key point of this invention is to provide a method for updating an on-vehicle battery model. Actual battery operating data is input into both the vehicle-side BMS battery model running within the vehicle's battery management system and the remote monitoring platform battery twin model running on a remote monitoring platform. The output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model are compared. If the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the remote monitoring platform re-identifies the battery parameters using the actual battery operating data and updates the parameters of both the vehicle-side BMS battery model and the remote monitoring platform battery twin model using the re-identified battery parameters. By using the vehicle-side BMS battery model and the battery twin model in the remote monitoring platform to calculate and output the results of the battery operating data, and then comparing them, the parameters of the vehicle-side BMS model can be updated in a timely manner, making the model's calculation results more accurate.

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] Electric vehicle example:

[0026] An electric vehicle according to this embodiment includes a battery information acquisition unit and a vehicle-side processing unit. The battery information acquisition unit is used to acquire actual battery operating data. The vehicle-side processing unit is used to input the actual battery operating data into the vehicle-side BMS battery model, and to update the battery parameters of the vehicle-side BMS battery model using the battery parameters re-identified by the remote monitoring platform when the difference between the output values ​​of the vehicle-side BMS battery model and the battery twin model of the remote monitoring platform is greater than a set difference threshold.

[0027] Electric vehicles also include gas composition detection sensors and wireless transceiver modules. The battery management system (BMS) within the battery pack, equipped with these sensors, directly uses wireless communication to read battery pressure, gas composition, voltage, and temperature information from the battery, and current information from the vehicle's BMS main controller. Using this collected information, the battery's condition can be directly diagnosed and estimated. The diagnostic tool can be connected to the electric vehicle either individually to a single battery pack or to the BMS main controller, allowing monitoring of one battery pack or simultaneous monitoring of multiple battery packs via the main controller. Specific details are as follows... Figure 1 As shown.

[0028] In electric vehicles, the battery parameters of the vehicle-side BMS battery model are updated using battery parameters re-identified by a remote monitoring platform, employing an on-vehicle battery model update method.

[0029] The specific steps of the vehicle battery model update method are as follows: Actual battery operating data is input into both the vehicle-side BMS battery model running within the vehicle-side battery management system and the remote monitoring platform battery twin model running on the remote monitoring platform. The output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model are compared. If the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the remote monitoring platform re-identifies the battery parameters using the actual battery operating data and updates the parameters of both the vehicle-side BMS battery model and the remote monitoring platform battery twin model using the re-identified battery parameters. Specifically... Figure 2 As shown.

[0030] By building a cloud-based battery management model on a battery cloud platform, processing and identifying the parameters of the twin model online, constructing a mapping relationship between the entity and the twin, and enabling real-time interactive control, high-precision safety management of the power battery throughout its entire life cycle can be achieved.

[0031] The remote monitoring platform battery twin model refers to the battery model running on the remote monitoring platform. Its parameters and input data correspond one-to-one with the battery model on the vehicle. When the cloud uses powerful computing power and the latest battery data to update the parameters of the cloud-based battery model, remote calibration can be used to update the vehicle-side battery model. This compensates for the disadvantage of insufficient computing power on the vehicle side, which prevents online updates to the vehicle-side battery model. In other words, the cloud-based battery model is a twin of the vehicle-side battery model. The remote monitoring platform battery twin model is consistent with the vehicle-side BMS battery model, hence the name remote monitoring platform battery twin model.

[0032] Parameter identification specifically involves finding a set of parameters that makes the voltage output by the battery model as close as possible to the voltage of the actual battery. This parameter identification problem can be transformed into an optimization problem, where a solution is the estimated set of parameters. An optimization problem typically includes design parameters x, an objective function F(x), parameter boundary constraints, and constraint functions. The optimization solver adjusts the parameters x within the constraints to satisfy the specified objective function. The specific optimization process depends on the chosen optimization algorithm.

[0033] The model used can be replaced according to actual needs, as shown below:

[0034] The interior model can be an Ohmic internal resistance model, specifically as follows: Figure 4As shown. In the case of an ohmic internal resistance model within the vehicle, the parameters are the internal resistance R and the voltage source voltage Em. The internal resistance R is a fixed value, and the voltage source voltage Em is used to simulate the open-circuit voltage. The parameters R and Em are obtained through offline identification of the battery model parameters used in the actual vehicle using a computer application. First, initial values ​​are assigned to the parameters R and Em, and upper and lower limits are defined. The ohmic internal resistance model is input with a working current i(t), and the model outputs a corresponding working voltage u1(t). Then, the working voltage u1(t) is compared with the actual battery output voltage u0(t), and the battery model parameters are modified according to the least squares estimation algorithm until the difference between u1(t) and u0(t) is less than a set difference threshold.

[0035] The interior model can be a Thevenin model, specifically as follows: Figure 5 As shown. When the in-vehicle model is a Thevenin model, the battery operating data specifically includes the actual battery operating current, voltage source voltage, and ambient temperature; the output variables are the battery internal temperature, remaining battery capacity, consumed energy, and terminal voltage; the parameters are internal resistance R0, voltage source voltage Em, resistance value R1, and capacitance value C1. The parameters internal resistance R0, voltage source voltage Em, resistance value R1, and capacitance value C1 are obtained through offline identification of the battery model parameters used in the actual vehicle using a computer application. First, initial values ​​are assigned to the parameters internal resistance R0, voltage source voltage Em, resistance value R1, and capacitance value C1, and upper and lower limits are defined. The operating current i(t) is input to the Thevenin model, and the model outputs the corresponding operating voltage u1(t); then, the operating voltage u1(t) is compared with the actual battery output voltage u0(t), and the battery model parameters are modified according to the least squares estimation algorithm until the difference between u1(t) and u0(t) is less than the set difference threshold. Specifically, as follows... Figure 3 As shown.

[0036] The interior model can be a PNGV model, specifically as follows: Figure 6As shown. When the in-vehicle model is a PNGV model, the parameters are internal resistance R0, voltage source voltage Em, resistance R1, capacitance C1, and capacitance C0. Capacitor C0 simulates the battery's hysteresis voltage, further increasing the accuracy of the battery model. The parameters internal resistance R0, voltage source voltage Em, resistance R1, capacitance C1, and capacitance C0 are obtained through offline identification of the battery model parameters used in the actual vehicle using a computer application. First, initial values ​​are assigned to the parameters internal resistance R0, voltage source voltage Em, resistance R1, capacitance C1, and capacitance C0, and upper and lower limits are defined. The operating current i(t) is input to the Thevenin model, and the model outputs the corresponding operating voltage u1(t). Then, the operating voltage u1(t) is compared with the actual battery output voltage u0(t), and the battery model parameters are modified according to the least squares estimation algorithm until the difference between u1(t) and u0(t) is less than the set difference threshold.

[0037] The interior model can be a high-order RC model, specifically as follows: Figure 7 As shown. When the in-vehicle model is a high-order RC model, the parameters are: internal resistance R0, voltage source voltage Em, resistance R1, capacitance C1, and capacitance C. n The resistance value R of the resistor n The more parallel RC pairs a high-order RC model has, the stronger its ability to simulate battery polarization characteristics. However, simply increasing the model order does not significantly improve accuracy, but drastically increases computational complexity. Therefore, first-order or second-order battery models are generally used. The parameters include internal resistance R0, voltage source voltage Em, resistance R1, capacitance C1, and capacitance C. n The resistance value R of the resistor n The battery model parameters of the actual vehicle battery are identified through offline computer identification. First, the parameters are: internal resistance R0, voltage source voltage Em, resistance value R1, capacitance value C1, and resistance value R. n The capacitance value C of the capacitor n Assign initial values ​​and limit the upper and lower limits, input the operating current i(t) to the Thevenin model, and the model outputs the corresponding operating voltage u1(t); then compare the operating voltage u1(t) with the actual battery output voltage u0(t), and modify the battery model parameters according to the least squares estimation algorithm until the difference between u1(t) and u0(t) is less than the set difference threshold.

[0038] The aforementioned Ohmic resistance model, Thevenin model, PNGV model, and higher-order RC model all belong to equivalent circuit models. Besides these equivalent circuit models, there are several other types of battery models, each with its own characteristics, revealing the internal state of the battery from a specific perspective. These are detailed in Table 1.

[0039] Table 1

[0040]

[0041] Example of a method for updating the vehicle battery model:

[0042] This invention also provides a method for updating an on-vehicle battery model. Actual battery operating data is input into both the vehicle-side BMS battery model running within the vehicle's battery management system and the remote monitoring platform battery twin model running on a remote monitoring platform. The output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model are compared. If the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the remote monitoring platform re-identifies the battery parameters using the actual battery operating data and updates the battery parameters of both the vehicle-side BMS battery model and the remote monitoring platform battery twin model using the re-identified battery parameters. The specific process, function, and effects have been described in detail in the embodiments of electric vehicles and will not be repeated here.

[0043] Vehicle-side processing unit example:

[0044] This invention also provides a vehicle-side processing unit. This unit is used to input actual battery operating data into the vehicle-side BMS battery model, and to update the battery parameters of the vehicle-side BMS battery model using battery parameters re-identified by the remote monitoring platform when the difference between the output values ​​of the vehicle-side BMS battery model and the battery twin model of the remote monitoring platform exceeds a set difference threshold. The specific process, function, and effects have been described in detail in embodiments of electric vehicles and will not be repeated here.

[0045] Remote processing unit embodiment:

[0046] This invention also provides a remote processing unit. This unit is used to input actual battery operating data into a battery twin model running on a remote monitoring platform. When the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the unit uses the actual battery operating data to re-identify the battery parameters and updates the battery parameters in the remote monitoring platform battery twin model using the re-identified battery parameters. The specific process, function, and effects have been described in detail in the embodiments of the electric vehicle and will not be repeated here.

[0047] Specific implementation methods have been given above, but the present invention is not limited to the described implementation methods. The basic idea of ​​the present invention lies in the above basic scheme. For those skilled in the art, designing various modified models, formulas, and parameters based on the teachings of the present invention does not require creative effort. Changes, modifications, substitutions, and variations made to the implementation methods without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for updating a vehicle battery model, characterized in that, The actual battery operating data is input into the vehicle-side BMS battery model running in the vehicle-side battery management system and the remote monitoring platform battery twin model running in the remote monitoring platform. The output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model are compared. If the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model is greater than a set difference threshold, the remote monitoring platform uses the actual battery operating data to re-identify the battery parameters and updates the battery parameters of the vehicle-side BMS battery model and the remote monitoring platform battery twin model using the re-identified battery parameters.

2. The vehicle battery model update method according to claim 1, characterized in that, The difference refers to the absolute value of the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model, and the set difference threshold is a set difference threshold.

3. The vehicle battery model update method according to claim 1, characterized in that, The vehicle-side BMS battery model can be an equivalent circuit model, an electrochemical model, a mathematical model, a thermal model, or an aging model. Specifically, the equivalent circuit model is a model that uses circuitry to simulate battery operation; the electrochemical model is a model that uses the principles of chemical reactions to simulate the battery; the mathematical model is a model that uses mathematical theories and experience to simulate battery characteristics; the thermal model is a model that models the relationship between internal electrochemical reactions and heat during charging and discharging; and the aging model is a model that models battery capacity and power degradation.

4. The vehicle battery model update method according to claim 1, characterized in that, The equivalent circuit model is the Ohm internal resistance model, Thevenin model, PNGV model, or a higher-order RC model.

5. The vehicle battery model update method according to claim 4, characterized in that, When the vehicle-side BMS battery model is an Ohmic internal resistance model, the battery parameters include the internal resistance and voltage source voltage in the model; when the vehicle-side BMS battery model is a Thevenin model, the battery parameters include the internal resistance, voltage source voltage, resistance value of resistors, and capacitance value of capacitors in the model; when the vehicle-side BMS battery model is a PNGV model, the battery parameters include the internal resistance, voltage source voltage, resistance value of resistors, and capacitance value of each capacitor in the model. When the vehicle-side BMS battery model is a high-order RC model, the battery parameters are the internal resistance, voltage source voltage, resistance value of each resistor, and capacitance value of each capacitor in the model.

6. The vehicle battery model update method according to claim 3 or 4, characterized in that, When the vehicle-side BMS battery model is an equivalent circuit model, the method for battery parameter identification is as follows: assign initial values ​​to the battery parameters of the model and limit the upper and lower limits, input the operating current to the model to obtain the corresponding operating voltage, compare the operating voltage with the actual voltage, and correct the battery parameters of the model so that the difference between the operating voltage and the actual voltage is less than the set difference threshold. When the difference between the operating voltage and the actual voltage is less than the set difference threshold, the battery parameters in the model are the identified battery parameters.

7. The vehicle battery model update method according to claim 3, characterized in that, When the vehicle-side BMS battery model is an equivalent circuit model, the actual battery operating data includes battery current, temperature, and voltage.

8. A vehicle-end processing unit, characterized in that, The vehicle-side processing unit is used to input the actual battery operation data into the vehicle-side BMS battery model, and to update the battery parameters of the vehicle-side BMS battery model using the battery parameters re-identified by the remote monitoring platform when the difference between the output values ​​of the vehicle-side BMS battery model and the battery twin model of the remote monitoring platform is greater than a set difference threshold.

9. A remote processing unit, characterized in that, The remote processing unit is used to input the actual battery operating data into the remote monitoring platform battery twin model running on the remote monitoring platform. When the difference between the output values ​​of the vehicle-side BMS battery model and the remote monitoring platform battery twin model exceeds a set difference threshold, the unit uses the actual battery operating data to re-identify the battery parameters and updates the battery parameters of the remote monitoring platform battery twin model using the re-identified battery parameters.

10. An electric vehicle, characterized in that, It includes a battery information acquisition unit and a vehicle-side processing unit; the battery information acquisition unit is used to collect actual battery operating data; the vehicle-side processing unit is used to input the actual battery operating data into the vehicle-side BMS battery model, and to update the battery parameters of the vehicle-side BMS battery model using the battery parameters re-identified by the remote monitoring platform when the difference between the output values ​​of the vehicle-side BMS battery model and the battery twin model of the remote monitoring platform is greater than a set difference threshold.

Images