Methods and devices for determining the state of charge of a battery

Abstract

This application proposes a method for estimating the state of charge (SOC) of a battery. The method comprises the following steps: S1: Determining the reference current consumption of a slave control unit of a battery management system connected to the battery, wherein the reference current consumption is determined offline; S2: Determining the current operating state information of the slave control unit in a real-world operating scenario; S3: Determining the actual current consumption of the slave control unit based on the reference current consumption and the current operating state information; S4: Estimating the SOC of the battery based on the actual current consumption of the slave control unit. This application also proposes a device for estimating the state of charge of a battery, a battery management system, a battery system, a vehicle, and a computer program product.

Description

TECHNICAL AREA

[0001] This application relates to a method for estimating the state of charge of a battery, as well as a device for estimating the state of charge of a battery, a battery management system, a battery system, a vehicle and a computer program product. STATE OF THE ART

[0002] A battery management system (BMS) is a key component that ensures the safe and efficient operation of batteries in electric vehicles and energy storage systems. One of the core functions of a battery management system is the accurate estimation of the battery's state of charge (SOC), which is crucial for battery energy management, lifespan prediction, and performance optimization.

[0003] Traditional methods for estimating battery state of charge (SBC) include the ampere-hour integration method. While widely used, this method has limitations in accurately capturing minute currents. This means that the power consumption of the battery management system's slave control unit cannot be fully accounted for in online SBC estimations. This uncaptured power consumption can accumulate over time, leading to a decrease in the accuracy of the battery SBC determination.

[0004] Therefore, existing technologies still have shortcomings in determining the state of charge of batteries. CONTENT OF THE INVENTION

[0005] The aim of this application is to provide a method for estimating the state of charge of a battery, a device for estimating the state of charge of a battery, a battery management system, a battery system, a vehicle and a computer program product in order to solve at least some of the problems of the prior art.

[0006] According to a first aspect of the present invention, a method for displaying images for a vehicle is provided, the method comprising the following steps: S1: Determining the reference current consumption of the slave control unit of the battery management system connected to the battery, whereby the reference current consumption is determined offline; S2: Determine the actual operating status information of the slave control unit in the real operating scenario; S3: Determine the actual power consumption of the slave control unit based on the slave control unit's reference power consumption and information on the actual operating conditions; and S4: Estimate the battery charge level based on the actual power consumption of the slave control unit.

[0007] This application incorporates the following technical concept: By combining the offline testing technology of the slave control unit with information about actual operating conditions, the high precision requirement for the current sensing device in practical use is cleverly circumvented, while the various complex situations that arise in practical use can be dynamically taken into account. This improves the flexibility and accuracy of the battery management system in estimating the battery's state of charge.

[0008] In an exemplary implementation, step S4 comprises the following: estimating the rough state of charge of the battery by integrating the battery's charge and discharge currents over a predetermined period using the master control unit of the battery management system; and correcting the rough state of charge based on the actual current consumption of the slave control unit to obtain the accurate state of charge of the battery, and determining the accurate state of charge as the battery's state of charge. Therefore, it is possible to optimize traditional state-of-charge estimation strategies without significantly altering the existing battery management system architecture.

[0009] In one embodiment, the information on the actual operating state includes the actual operating time of the slave control unit under various preset operating conditions within a predetermined period. Step S3 includes calculating the actual power consumption of the slave control unit using a time-weighted method with the following formula: Pact=N×∑i=1m(Pref,i×ti)

[0010] In, P act This is the actual power consumption of the control unit. P ref,i The slave control unit is located in the first reference power consumption under preset operating conditions. iis the actual operating time of the slave control unit under the i-th preset operating condition, and m is the number of preset operating conditions in which the slave control unit participates within a predetermined period. N is the number of slave control units included in the battery management system. Therefore, the actual power consumption of the slave control unit can be estimated more accurately based on the operating time allocation under different operating conditions, thus improving the accuracy of the state-of-charge estimation.

[0011] In an exemplary embodiment, step S2 comprises the following: the use of a battery management system to determine the preset operating state of the slave control unit by monitoring the current direction, current intensity, charging interface type, and battery voltage; and the use of a timing chip of the battery management system to record the actual operating time of the slave control unit under the preset operating state. This method of calculating power consumption, which differentiates between operating conditions, takes into account the changes in the power consumption of the slave control unit under different operating states and thus improves the accuracy of the state-of-charge estimation.

[0012] In one embodiment, the actual operating state information includes the actual operating conditions of the slave control unit under each preset operating state within a predetermined time period. Step S3 involves: correcting the reference current consumption based on the deviation between the actual operating conditions and the reference operating conditions used in the offline determination of the reference current consumption, and determining the actual current consumption based on the corrected reference current consumption. This allows for a more accurate correction of the reference current consumption and thus improves the accuracy of the actual current consumption estimate.

[0013] In an exemplary embodiment, step S3 comprises: determining a correction factor based on the deviation between the actual operating conditions and the reference operating conditions, and correcting the reference current consumption by superimposing the correction factor onto the reference current consumption. The correction factor is determined based on the deviation between the actual operating conditions and the reference operating conditions with respect to temperature, humidity, vehicle load, and / or road conditions. The difference between offline test conditions and actual operating conditions can be quantified using a correction factor, which allows for dynamic adjustment of the calibration values ​​for current consumption.

[0014] In one exemplary embodiment, the preset operating conditions include normal operating conditions and energy-saving operating conditions, wherein the slave control unit is continuously switched on under normal operating conditions and switched off or switched on only periodically under energy-saving operating conditions; and / or the preset operating conditions include: DC charging conditions, AC charging conditions, driving discharge conditions, timed wake-up conditions, sleep compensation conditions, and full sleep conditions. Since the actual power consumption of the slave control unit changes with the operating conditions, a suitable reference power consumption can be dynamically selected by defining a variety of preset operating conditions. Compared to using a single static power reference, this ensures the accuracy of the power estimation even under changing operating conditions.

[0015] In an exemplary embodiment, the reference current consumption and / or the actual current consumption of the slave control unit under energy-saving conditions are determined as follows: The reference current consumption and / or the actual current consumption of the slave control unit are determined separately for the cases in which the slave control unit is in the operating state and in the non-operating state under energy-saving conditions. By differentiating the energy-saving current consumption in different operating states, a more precise estimate of the energy-saving current consumption can be achieved.

[0016] In an exemplary embodiment, step S1 comprises the following: performing offline power consumption tests on the actual slave controllers in use and / or other slave controllers under a set of preset operating conditions; and calculating the average power consumption per unit of time for each offline-tested slave controller under each preset operating condition, as well as determining the reference power consumption based on the average power consumption per unit of time. Offline power consumption testing can reduce the reliance on high-precision current and voltage measuring devices in real-world applications, thereby reducing computational overhead and hardware costs while ensuring the accuracy of the state-of-charge estimation for the battery management system.

[0017] In an exemplary embodiment, step S1 comprises the following: simulating battery state and / or load changes under various preset operating conditions using a simulation test tool; measuring the current and voltage of the actual and / or additional slave control units using a high-precision current and voltage meter within a test time for each preset operating condition; and calculating the average current consumption per unit of time for each offline-tested slave control unit using the following formula: Pi=1ti2−ti1∫ti1ti2Vi(t)×Ii(t)dt

[0018] In, P i The slave control unit is located in the first... Average power consumption per unit of time under preset operating conditions t i1 It is the first test start time for each preset operating state. i2This is the first time I've seen the end time of the test under each preset operating condition. V i (t) The slave control unit is located in the first i voltage under preset operating conditions I i (t) The slave control unit is located in the first i current strength under preset operating conditions.

[0019] In an exemplary embodiment, step S1 comprises the following: storing a reference current consumption determined offline by the slave unit in a calibration database, either locally and / or in the battery management system's cloud; and retrieving the reference current consumption from the calibration database, either locally and / or in the battery management system's cloud, in response to requests for battery state-of-charge estimation and / or correction. Storing offline measurement results ensures that this reference data can be retrieved quickly and accurately during the battery management system's operation. This improves the accuracy and efficiency of battery state-of-charge determination and reduces the overhead of real-time calculations.

[0020] According to a second aspect of this application, a device for estimating the state of charge of a battery is provided, the device comprising a memory and a processor, the memory storing computer program instructions which, when executed by the processor, enable the processor to perform the method according to the first aspect of this application.

[0021] According to a third aspect of this application, a battery management system is provided which includes a master control unit and a slave control unit, wherein the master control unit includes the device according to a second aspect of this application.

[0022] In one exemplary embodiment, the battery management system includes a human-machine interface configured to: output the battery's state of charge (SOC) and / or a rough, uncorrected SOC based on the actual power consumption of the slave control unit; adjust the SOC estimation frequency based on user input; and / or adjust the type and number of preset operating states considered when calculating the slave control unit's actual power consumption based on user input. This provides the user with real-time information about the battery's state of charge and an overview of the battery capacity at various correction levels.

[0023] According to a fourth aspect of this application, a battery system is provided which includes a battery and a battery management system according to a third aspect of this application, which is connected to the battery.

[0024] According to a fifth aspect of this application, a vehicle is provided, the vehicle comprising the device according to a second aspect of this application, the battery management system according to a third aspect of this application and / or the battery system according to a fourth aspect of this application.

[0025] According to a sixth aspect of this application, a computer program product is provided with program code units, wherein the program code units are configured such that the computer performs the procedure according to a first aspect of this application when the computer program product is executed on a computer or stored on a computer-readable storage medium. DESCRIPTION OF THE FIGURES

[0026] The present invention is described in more detail below with reference to the figures, so that its principles, features, and advantages become even clearer. The figures include the following: Fig. shows a block diagram of a battery system according to an embodiment of this application; Fig. shows a block diagram illustrating the detailed configuration of the main control unit of a battery management system according to an embodiment of this application; Fig. shows a block diagram of an offline test circuit for determining the reference current consumption of a slave control unit of a battery management system according to an embodiment of this application; Fig. Figure 4 shows a flowchart of a method for displaying images in a vehicle according to an exemplary embodiment of the present invention. Fig. shows a flowchart of step S1 of the in Fig. presented method; Fig. shows a flowchart of steps S2 and S3 of the in Fig. described procedure; and Fig. shows a flowchart of steps S2 and S3 of the in Fig. presented method. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0027] To better illustrate the technical problems to be solved, the technical solutions, and the advantageous technical effects of the present invention, the present invention will be described in more detail with reference to the figures and exemplary embodiments. It should be understood that the specific embodiments described here serve only to explain the present invention and not to limit its scope of protection.

[0028] Fig. Figure 1 shows a block diagram of battery system 1. This battery system 1 can, for example, be installed in a vehicle. The vehicle can be powered via battery 10 for driving or for operating electronic components such as audio and air conditioning. In this context, a vehicle could be, for example, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle with extended range (EREV), or a battery electric vehicle (BEV).

[0029] Battery system 1 comprises a battery 10 (also commonly referred to as a battery) and a battery management system 20. The battery 10 comprises several battery modules M1, M2, and M3 connected in series and / or parallel. The battery modules M1, M2, and M3, in turn, comprise several battery cells C1, C2, and C3 connected in series. In practical applications, the output power of the battery 10 can be adjusted by increasing or decreasing the number of connected battery modules M1, M2, and M3. Fig. The external device 50 is connected between the two output terminals OUT+ and OUT- of the battery 10, so that the battery 10 can supply the external device 50 with the required energy. The external device 50 can be a load (e.g., a drive motor, a control unit, etc.) or a secondary battery.

[0030] As in Fig. As shown, the battery management system 20 has a master-slave architecture, which includes, for example, a master control unit (BCU) and several slave control units (BMU1, BMU2 and BMU3).

[0031] The main control unit (BCU) monitors and adjusts the overall condition and function of battery 10. This condition includes, for example, voltage, current, and / or temperature. The master control unit (BCU) communicates with several slave control units (BMU1, BMU2, and BMU3) to collect information from each slave control unit and control their operation. Communication between the master control unit (BCU) and the slave control units (BMU1, BMU2, and BMU3) can occur via various protocols, such as the CAN bus or wireless communication, to ensure real-time capability and reliability of data transmission. The main control unit (BCU) is also responsible for estimating the state of charge of battery 10.Typically, the main control unit (BCU) receives current measurement results from the current measuring unit 22, which is located in the main charging and discharging circuit, and uses these results to estimate the approximate state of charge of the battery 10 using the ampere-hour integration method. Fig. The current measuring unit 22 is connected, for example, between the positive terminal of battery 10 and the output terminal OUT+. It should be noted that, although the main control unit BCU and the current measuring unit 22 are in Fig. The current measuring unit 22, which is shown as separate components, can also be part of the main control unit BCU.

[0032] Each slave control unit (BMU1), BMU2, and BMU3 is connected to its corresponding battery modules (M1, M2, and M3) and is responsible for monitoring the real-time status of each module. This includes key parameters such as voltage, current, and temperature of cells C1, C2, and C3 within each battery module. The slave control units BMU1, BMU2, and BMU3 transmit this data to the master control unit (BCU), which then processes the data and executes the battery management strategy. The slave control units BMU1, BMU2, and BMU3 are also used to perform voltage balancing operations when voltage differences exist between the various battery modules M1, M2, and M3. For example, the slave control units BMU1, BMU2, and BMU3 can establish a current path between the two ends of each battery module M1, M2, and M3 (or cell C1, C2, and C3) and set switching elements along this path.By controlling the switching elements, the voltage of each battery module M1, M2, and M3 can be decreased or increased. In this way, voltage balancing can be achieved.

[0033] Regarding power supply, the main control unit (BCU) is powered by a DC / DC converter or a secondary battery (not shown) located between the output terminals OUT+ and OUT- of battery 10, while the slave control units (BMU1, BMU2, and BMU3) are powered directly by the battery modules (M1, M2, and M3) that they monitor. The type of power supply for the master control unit (BCU) and the slave control units (BMU1, BMU2, and BMU3) directly affects the accuracy of the state-of-charge estimation.

[0034] The power supply method of the main control unit (BCU) dictates that it is located in the main charging and discharging circuit of the battery, so its influence as a load can be reflected by the reading of the current measuring unit 22, which is located in the main charging and discharging circuit. Therefore, the power consumption of the main control unit (BCU) has already been included and taken into account in the traditional state-of-charge estimation.

[0035] In contrast, the slave control units BMU1, BMU2, and BMU3 are powered directly by the battery modules M1, M2, and M3 they monitor. Their own operating current is actually derived from the current of the battery modules M1, M2, and M3. This component is not directly reflected in the current measurement of the main circuit and can therefore be easily neglected when estimating the state of charge using ampere-hour integration. Since the electrical energy consumed by the slave control units BMU1, BMU2, and BMU3 directly reduces the actually usable energy of the battery modules M1, M2, and M3, if this is not taken into account when estimating the state of charge, the estimated state of charge will be too high, which impairs the battery management system 20's accurate assessment of the remaining battery capacity.To accurately assess these effects, highly precise current measurement technology is theoretically required to monitor the current of the control units BMU1, BMU2, and BMU3. In practice, however, such high-precision current meters prove not only to be expensive but also to significantly increase the size of the battery management system.

[0036] In the context described above, the battery management system 20 also includes a device 21 for estimating the state of charge of the battery 10, which is located in the Fig. The embodiment shown in Figure 1 is provided, for example, in the main control unit (BCU). Device 21 comprises a processor and a memory in which computer program instructions are stored. When the computer program instructions are executed by the processor, the processor can, for example, execute a procedure for estimating the state of charge of the battery (described below with reference to Figure 1). Fig. (described in detail). The instructions of the computer program can be stored on a computer-readable storage medium. Computer-readable storage media can include, for example, high-speed main memory (RAM), but also non-volatile memory such as hard disks, main memory, plug-in hard disks, smart memory cards, secure digital cards, flash memory cards, at least one hard disk storage device, a flash memory device, or other volatile solid-state storage devices. The processor can be a central processing unit or other general-purpose processors, digital signal processors, application-specific integrated circuits, commercially available programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0037] As in Fig. As shown, the battery management system 20 can optionally include a human-machine interface 25 configured to output the state of charge of the battery 10 and / or a rough state of charge that has not been corrected based on the actual power consumption of the slave control units BMU1, BMU2, and BMU3. Furthermore, the human-machine interface 25 can also adjust the estimation frequency of the battery 10's state of charge based on user input data. The type and number of preset operating conditions that are taken into account when calculating the actual power consumption based on user input can also be adjusted via the human-machine interface 25.This allows users to adjust the frequency of state-of-charge estimations as needed and to select the type and number of operating states to focus on, based on actual requirements (such as computational effort and time efficiency). This increases the personalization and adaptability of system operation.

[0038] Fig. shows a block diagram illustrating the detailed configuration of the main control unit (BCU) of a battery management system 20 according to an exemplary embodiment of this application.

[0039] As in Fig. As shown, the main control unit (BCU) can include, in addition to the device 21 for estimating the state of charge of the battery, a conventional SOC estimating unit 27, a timing chip 28 and a communication unit 29.

[0040] The conventional SOC estimating unit 27 estimates the rough state of charge of the battery based on the measured value of the current measuring unit 22 in the main charging and discharging circuit and the ampere-hour integration method.

[0041] The timing chip 28 serves to provide a precise time reference. In addition, it can also record the actual operating time of the slave control units BMU1, BMU2 and BMU3 under the respective preset operating conditions.

[0042] The communication unit 29 is responsible for sending instructions to the individual slave control units BMU1, BMU2 and BMU3 and receiving data in order to control the operating mode of the slave control unit battery 1.

[0043] In this embodiment, the device 21 can, for example, function as a correction unit. It receives the approximate state of charge of the battery 10 from the conventional state-of-charge measurement unit 27 and reads the actual operating time of the slave control units BMU1, BMU2, and BMU3 under their respective preset operating states from the timing chip 28. It then uses the calculated actual current consumption of the slave control units BMU1, BMU2, and BMU3 to correct the conventional state-of-charge estimate, thereby improving the estimation accuracy.

[0044] Fig. Figure 1 shows a block diagram of an offline test circuit for determining the reference current consumption of a slave control unit of a battery management system according to an embodiment of this application. The offline test circuit comprises the battery system 1 to be tested. The system includes a simulation test tool 40, a high-precision current measuring unit 41, a high-precision voltage measuring unit 42, and an offline calculation unit 47.

[0045] In one embodiment of this application, the battery management system 20 can be disassembled in practical use to test the slave control units BMU1, BMU2, and BMU3 individually. In another embodiment, a different battery management system 20 with the same specifications can also be used. The supplied slave control unit BMU1, BMU2, and BMU3 are used. Perform tests and apply the test results to the slave control units BMU1, BMU2, and BMU3 in actual use. Battery 10 was used in offline testing. (Battery module M1, M2, M3, and battery cell C1, C2, C3), connectors, and battery management system 20. The main control unit (BCU) and the rest of the components are also used. Both the hardware and software configurations must strictly adhere to battery system design standards in practical applications.

[0046] The simulation test tool 40 typically comprises a host computer and a test stand connected to the battery system 1 under test. The output terminals OUT+ and OUT- are used to simulate the battery status and / or load changes under various preset operating conditions. The slave control unit BMU1, BMU2, and BMU3 provide a controllable test environment to ensure the consistency and repeatability of the test conditions.

[0047] To achieve high-precision measurement, each slave control unit BMU1 has its own control unit. 'BMU2' 'BMU3' Each unit is equipped with a separate high-precision current measuring unit 41 and a high-precision voltage measuring unit 42, which can monitor and record each slave control unit BMU1 in real time. Current and voltage under various preset operating conditions are sent to the offline processing unit 47. More precisely, the high-precision voltage measuring unit 42 is connected to each slave control unit to measure its voltage. The high-precision current measuring unit 41 measures the current flowing through the slave control unit.

[0048] The offline processing unit 47 is responsible for collecting and processing data from the high-precision current measuring unit 41 and the high-precision voltage measuring unit 42, as well as for offline power consumption calculation and analysis based on the test time, thus determining the power consumption of each slave control unit BMU1, BMU2, and BMU3. This determines the average power consumption per time unit under the respective preset operating conditions. After calculating the average power consumption of each slave control unit within a time unit, the offline processing unit 47 can further process the data (e.g., calculate the mean, eliminate outliers and / or filter, etc.) and determine the reference power consumption of the slave control unit under each preset operating condition.

[0049] Before conducting offline tests, the ambient temperature can be set to 25 ± 2°C, the humidity to 40–60%, and interference from external batteries can be shielded. Disassemble the currently used battery system or a system with the same specifications and connect the high-precision current measuring unit 41 and the high-precision voltage measuring unit 42 (e.g., current accuracy ≤ 0.01 mA, measuring range 0 A–5 A; voltage accuracy ≤ 0.01 mV, measuring range 0 V–100 V) to the slave control circuit. Then, using the simulation test tool 40, a series of preset operating conditions is simulated while simultaneously recording the data acquired by the high-precision current and voltage measuring units 41 and 42 for use by the slave control unit BMU1. Reference current consumption analysis provides an accurate data basis.

[0050] In an embodiment not shown, multiple (e.g., five) battery systems with the same specifications can also be tested offline in parallel. The test time for each preset operating state is, for example, at least 200 hours. By averaging the offline test results of multiple slave control units with respect to quantity and time, the reliability and accuracy of the obtained reference current consumption can be effectively improved.

[0051] Fig. Figure 4 shows a flowchart of a method for displaying images in a vehicle according to an exemplary embodiment of the present invention.

[0052] In step S1, the reference current consumption of the slave control unit of the battery management system connected to the battery is determined. The reference current consumption is determined offline.

[0053] In one embodiment, the reference power consumption is determined for several different preset operating conditions. For example, the reference current consumption of a slave control unit consists of several sub-items, each representing the average current consumption of one or more slave control units under a preset operating condition within a unit of time.

[0054] In one embodiment, the reference current consumption can be determined by offline current consumption tests on the actual and / or additional slave control units. The results of these offline tests are typically saved in advance so that they can be retrieved when needed.

[0055] In one embodiment, the slave control unit's reference current consumption data can also be collected via crowdsourcing. For example, offline test results from the control unit can be gathered from laboratories worldwide. These laboratories can conduct offline current consumption tests under various environmental conditions and generate diverse reference data by taking into account factors such as different road conditions, temperature, humidity, and simulated driving habits. The server collects and stores this data, thus creating a comprehensive reference database for current consumption. Vehicles in different regions can connect to the server via the network and, based on their specific environmental conditions and needs, use the most appropriate reference current consumption to estimate the battery's state of charge.

[0056] In step S2, information about the actual operating state of the slave control unit in the real operating scenario is determined.

[0057] Information on actual operating conditions includes, for example, two aspects: The first is the actual operating time of the control unit under various preset operating conditions within a predetermined period. The length of this period can be adjusted as needed. Generally, the predetermined period is, for example, the time interval since the last estimate of the battery's state of charge. A battery management system, for instance, can be used to determine the slave unit's preset operating conditions by monitoring the direction and magnitude of the battery current, the type of connected charging interface, and the voltage. The direction and magnitude of the current indicate whether the battery is charging or discharging, while voltage and temperature measurements can provide further details about the battery's current state.Subsequently, the actual operating time of the slave control unit can be recorded under preset operating conditions using the built-in (RTC) timing chip of the battery management system or other time recording devices.

[0058] Secondly, the actual operating conditions of the control unit under various preset operating conditions within a predetermined period. This includes a range of environmental parameters that can affect battery performance (such as temperature, humidity, ambient pressure, weather conditions, road gradient, and road condition information). Furthermore, the actual operating conditions can include the state parameters of the vehicle and / or the battery management system (such as charge / discharge rate, chemical reaction rate within the battery, vehicle load, vehicle speed, acceleration, or deceleration). These parameters can be acquired from the vehicle's own sensors or obtained from external sources via a communication interface.Through a comprehensive analysis of the parameters of the above-mentioned reaction conditions, the battery management system can more accurately assess the state of the slave control unit in actual use.

[0059] In step S3, the actual power consumption of the slave control unit is determined based on the reference power consumption of the slave control unit and information about the actual operating conditions.

[0060] Actual power consumption can be determined in various ways. For example, a reference power consumption can be specifically selected based on the preset operating mode, quantity, and duration of the values ​​contained in the actual operating state information. The actual power consumption can then be calculated from the selected reference power consumption. Alternatively, the reference power consumption can be corrected using information about the actual operating conditions, and the actual power consumption can then be calculated based on the corrected reference power consumption. This will be explained below with reference to the Fig. Described in detail and not repeated here.

[0061] In step S4, the battery's state of charge is estimated based on the actual power consumption of the slave control unit.

[0062] In one embodiment, the battery's state of charge is estimated in two steps.

[0063] First, the main control unit of the battery management system receives the battery's charging and discharging current from the current measuring unit in the main charging and discharging circuit and estimates the battery's rough state of charge by integrating the current over a predetermined period. This preliminary estimation process can be expressed by the following formula: SOC=SOC0−∫t1t2I(t)dtQ

[0064] In, SOC For an approximate state of charge, SOC0 To estimate the initial state of charge, I(t) This represents the charging and discharging current of the battery during the estimation period (negative when charging, positive when discharging). Q This is the nominal capacity of the battery. t1 Indicates the start time of the estimation. t2 This marks the end time of the estimation.

[0065] The rough charge level mentioned above is then corrected using the actual power consumption of the slave control unit to obtain the precise battery charge level. This precise charge level can ultimately be determined as the battery's state of charge. This correction process can be expressed by the following formula: SOC'=SOC−PactQ

[0066] In, SOC' For the exact state of charge of the battery, SOC For an approximate state of charge, P act The actual power consumption of the control unit during the estimated period (i.e., within the specified time period). This is the nominal capacity of the battery.

[0067] Alternatively, the two steps described above can be integrated, and the state of charge can be estimated directly using the following formula: SOC'=SOC0−∫t1t2I(t)dt+PactQ

[0068] In ,SOC' For the exact state of charge of the battery , SOC0 To estimate the initial state of charge , P act The actual power consumption of the control unit during the estimation period. Q is the nominal capacity of the battery. t1 indicates the start time of the estimation. t2 indicates the end time of the estimation. I(t) represents the charging and discharging current of the battery during the estimation period (negative during charging, positive during discharging).

[0069] Fig. shows a flowchart of step S1 of the in Fig. method shown. In this embodiment, step S1 comprises the method described in Fig. The procedures shown in section 4, for example, include sub-steps S11 to S14.

[0070] In sub-step S11, offline power consumption tests are performed on the actual slave control unit and / or other slave control units used in the battery management system under a series of preset operating conditions. Specifically, battery state and / or load changes under various preset operating conditions can be simulated using simulation tools. For each preset operating condition, the current and voltage of the actual and / or other slave control units can be measured within the test period using high-precision current and voltage measuring devices.

[0071] In one embodiment, the preset operating conditions include normal operating conditions and energy-saving operating conditions. In normal operation, the slave control unit is permanently switched on or operates at full power to meet the frequent need for battery status monitoring during driving or charging. In this case, the slave control unit must monitor parameters such as voltage, current, and temperature of the battery module (and cells) in real time to ensure the battery's safety and stability under high load. In energy-saving mode, the slave control unit is switched off or only switched on periodically to meet the reduced need for battery monitoring when the vehicle is parked and switched off, thus achieving energy savings.

[0072] Normal operating conditions include, for example: □AC charging mode, in which AC chargers are used to charge the vehicle or battery system; □DC charging mode, in which DC chargers are used to charge the entire vehicle or battery system; □Discharge conditions during driving, such as the CLTC (China Light-duty Vehicle Test Cycle). The CLTC test cycle is a driving test standard unique to China. It takes into account various factors such as road conditions, traffic situation, and driving habits in China and is primarily used to test the energy consumption and emissions of light commercial vehicles. The CLTC test lasts a total of 1800 seconds and includes three speed ranges: low, medium, and high, to simulate energy consumption and emissions in congested urban areas, normal city traffic, suburban areas, and on highways, respectively. The powertrain discharge conditions can be adapted to local conditions. For example, the test duration, average speed, and idling time can be adjusted to the traffic conditions and driving behavior in different countries.

[0073] To simulate battery state and load changes under preset operating conditions, simulation test tools can generate a voltage-current characteristic (VI characteristic) (often referred to as a MAP table) based on real vehicle driving data and actual charging data, thus enabling an accurate simulation of battery charging and discharging curves. Furthermore, it can not only provide static test conditions but also simulate various dynamic states under preset operating conditions, such as high-temperature faults, open circuits, short circuits, and / or communication interruptions.

[0074] Energy-saving operating conditions include, for example: □The timed wake-up mode is a mode in which the battery management system wakes up from sleep mode at set times to check information such as cell voltage, cell temperature, and state of charge (SOC). After completing the check, it returns to sleep mode. □In sleep mode, the battery management system sends a request for sleep mode balancing based on cell status inconsistencies before switching to sleep mode. This allows the slave control unit to continue operating and performing balancing operations on the cells after the battery management system switches to sleep mode. □Complete sleep mode: In this mode, the battery management system is switched off and enters sleep mode, i.e., a state without timed wake-up or sleep mode balancing.

[0075] In sub-step S12, the average power consumption per unit of time for each offline tested slave control unit is calculated under the respective preset operating conditions, and the reference power consumption is determined based on the average power consumption per unit of time.

[0076] Specifically, the average power consumption per unit of time for each slave control unit to be tested can be calculated using the following formula: Pi=1ti2−ti1∫ti1ti2Vi(t)×Ii(t)dt

[0077] In, P i The slave control unit is located in the first... Average power consumption per unit of time under preset operating conditions t i1 This is the first test start time for each preset operating state. i2 This is the first time I've seen the end time of the test under each preset operating condition. V i(t) The slave control unit is located in the first i voltage under preset operating conditions I i (t) The slave control unit is located in the first i current strength under preset operating conditions.

[0078] When testing AC charging conditions, for example, the battery can be charged according to the voltage-current characteristic of the vehicle's AC charging system, and the current and voltage of each slave control unit can be monitored and recorded at any time. Under AC charging conditions, the average current consumption of each slave control unit per unit of time is P. AC It can be calculated using the following formula: PAC=1tAC2−tAC1∫tAC1tAC2VAC(t)×IAC(t)dt

[0079] In, t AC1 Start time of the AC charging test t AC2 End time of the AC charging test V AC(t) This is the voltage at the control unit during the AC charging test. I AC (t) This is the current of the slave control unit during the AC charging test.

[0080] When testing DC charging conditions, for example, the battery can be DC charged according to the voltage-current characteristic of the entire vehicle, and the current and voltage of each individual control unit can be monitored and recorded at any time. Under DC charging conditions, the average current consumption of each slave control unit per unit of time is P. DC It can be calculated using the following formula: PDC=1tDC2−tDC1∫tDC1tDC2VDC(t)×IDC(t)dt

[0081] In, t DC1 Start time of the DC charging test t DC2 End time of the DC charging test DC (t) This is the voltage at the control unit during the DC charging test. I DC(t) This is the current of the slave control unit during the DC charging test.

[0082] When testing the CLTC operating state, for example, the battery can be discharged according to the voltage-current characteristic curve under CLTC operating conditions, and the current and voltage of each slave control unit can be monitored and recorded at any time. Under CLTC operating conditions, the average current consumption of each slave control unit per unit of time is P. CLTC It can be calculated using the following formula: PCLTC=1tCLTC2−tCLTC1∫tCLTC1tCLTC2VCLTC(t)×ICLTC(t)dt

[0083] In, t CLTC1 Start time of the CLTC discharge test t CLTC2 End time of the CLTC discharge test V CLTC (t) This is the voltage at the control unit during the CLTC discharge test. I CLTC (t) This is the current in the slave control unit during the CLTC discharge test.

[0084] When testing the timed wake-up mode, the battery management system is put into this mode. This means that the battery management system's slave control unit is activated at regular intervals (e.g., hourly or every two hours) to record voltage, temperature, internal pressure, and other signals from the battery module or cell. After the recording is complete, the slave control unit returns to sleep mode. When the slave control unit is woken up by a timer, the following average power consumption of each slave control unit per unit of time results: P RTC It can be calculated using the following formula: PRTC=1tRTC2−tRTC1∫tRTC1tRTC2VRTC(t)×IRTC(t)dt

[0085] In,t RTC1 This is the start time for the scheduled wake-up call. RTC2 The end time of the scheduled wake-up process. V RTC(t) This refers to the voltage at the control unit during the timed wake-up phase. I RTC (t) This is the current of the slave control unit during the timed wake-up phase.

[0086] For example, when testing the sleep balancing state, the battery management system is switched off and the sleep balancing request is triggered periodically, causing the slave control unit to perform the balancing process. When the slave control unit performs the sleep balancing task, the average power consumption of each slave control unit per unit of time is as follows: P Bal It can be calculated using the following formula: PBal=1tBal2−tBal1∫tBal1tBal2VBal(t)×IBal(t)dt

[0087] In,t Bal1 Beginning of hibernation equilibrium t Bal2 The point in time when equilibrium is reached during hibernation,V Bal (t) The voltage at the control unit during the sleep balance test. Bal (t) Current level of the slave control unit during the sleep balance test.

[0088] When testing a fully idle state, for example, the slave control unit can be put into idle mode, and each value can be calculated using the following formula. Average power consumption of the slave control unit per unit of time: PSleep=1tSleep2−tSleep1∫tSleep1tSleep2VSleep(t)×ISleep(t)dt

[0089] In,t Sleep1 The beginning of the hibernation equilibrium Sleep2 It is the end point of the hibernation equilibrium. V Sleep (t) This is the voltage at the control unit during the sleep compensation test. I Sleep (t) This is the current of the slave control unit during the sleep balancing test.

[0090] As mentioned previously, the average power consumption per unit of time was determined for each slave control unit under various preset operating conditions. For example, to determine the reference power consumption, the power consumption of all slave control units under test can be averaged over a period of time. Using DC charging as an example, the average power consumption of 10 slave control units per unit of time was determined through offline testing. DC1 , P DC2 ... P DC10 The reference current consumption of each slave control unit under DC charging conditions can be determined by adding their values ​​and then dividing by the number of slave units. ref,DC That is to say, it exists: Pref,DC=PDC1+PDC1+⋯PDC1010

[0091] In the embodiments shown above, determining the reference power consumption of the slave control unit in power-saving mode requires considering various operating states. First, when the slave control unit is in an operating state (for example, when the slave control unit is being woken up, performing battery status monitoring, or a voltage balancing operation), the first reference power-saving power consumption of the slave control unit is determined. This reference value reflects the power consumption of the slave control unit when performing tasks in power-saving mode. Conversely, when the slave control unit is in a non-operational state (i.e., in full sleep mode), the second reference power-saving power consumption of the slave control unit is determined.In this state, the energy consumption of the slave control unit is reduced to a minimum, as most functions are switched off to achieve maximum energy savings.

[0092] In another embodiment, the specific operating state of the slave control unit under power-saving conditions cannot be distinguished, and the reference power-saving consumption can be calculated directly according to different operating state categories. For example, when testing the timed wake-up condition, the total power consumption of the slave control unit over a specific period (including the wake-up and non-wake-up phases) can be calculated; when testing the sleep balancing condition, the total power consumption of the slave control unit over a specific period (including the sleep balancing task execution phase and the full sleep phase) can be calculated. This method is particularly suitable for applications where the power consumption control requirements are not very precise or where a reduction in computational effort is necessary.

[0093] In sub-step S13, the reference current consumption of the slave unit, which is determined offline, is stored in the calibration database.

[0094] The calibration database may contain, for example, the following: □Internet databases, such as those containing reference data on the power consumption of different models of slave control units in different countries or regions, allow for easy querying and retrieval as needed. □A local database for the vehicle and / or battery management system, used, for example, to store reference current consumption data corresponding to the slave control units actually used, to enable quick access and use.

[0095] In sub-step S14, a reference current consumption is retrieved from the battery management system's calibration database, either locally and / or in the cloud, according to the requirements for estimating and / or correcting the battery's state of charge. For example, critical, locally stored data can also be accessed without a network connection. Storing data in the cloud allows different vehicle or battery management systems to exchange data and supports real-time updates and the maintenance of reference current consumption data.

[0096] It should be noted that in this embodiment, while step S1 comprises four sub-steps, not all sub-steps need to be performed in actual operation. For example, if the battery management system can directly retrieve reference current consumption data compatible with the current vehicle and battery status, it can directly perform step S14, i.e., use this data directly for the subsequent estimation of actual current consumption and monitoring of battery status. However, if the vehicle is used in a new driving environment or uses a new battery management system, and therefore no historical reference data for current consumption is available, offline tests must first be performed. These results can then be used to update the local or cloud-based calibration database and provide the battery management system with the latest reference data.

[0097] Fig. shows a flowchart of steps S2 and S3 of the in Fig. the method described. In this embodiment, step S2 comprises the method described in Fig. The procedure shown in section 4 comprises sub-steps S21 and S22, and step S3 includes sub-step S31.

[0098] In sub-step S21, the preset operating conditions of the slave control unit are determined using the battery management system. As described above, the battery management system can be used to determine the preset operating conditions of the slave control unit by monitoring the direction and magnitude of the battery current, the type of connected charging interface, and the voltage.

[0099] In sub-step S22, the actual operating time of the slave control unit under preset operating conditions is recorded by the timing chip of the battery management system.

[0100] For example, if you want to estimate the current state of charge, identify all preset operating states applied by the slave control unit during the time interval since the last estimate of the state of charge, and record the actual operating time of the slave control unit under each preset operating state accordingly.

[0101] In sub-step S31, the actual power consumption of the slave control unit can be calculated using the time-weighted method and the following formula: Pact=N×∑i=1m(Pref,i×ti)

[0102] In, P act This is the actual power consumption of the control unit. P ref,i The slave control unit is located in the first reference power consumption under preset operating conditions. iis the actual operating time of the slave control unit under the i-th preset operating condition, and m is the number of preset operating conditions in which the slave control unit participates within a predetermined period. N is the number of slave control units included in the battery management system.

[0103] For example, 5 minutes have passed since the last battery charge status update. During these 5 minutes, the slave control unit operates successively in DC charging mode and driving discharge mode, with the DC charging mode lasting 4 minutes and the driving discharge mode lasting 1 minute. The battery management system comprises 10 slave control units. Therefore, the actual power consumption of the slave control unit during these 5 minutes can be calculated using the following formula: Pact=10×(Pref,DC×4+Pref,CLTC×1)

[0104] In, P ref,DCThis is the reference current consumption of the control unit under DC charging conditions. ref,CLTC This serves as a reference power consumption for the control unit during driving discharge (e.g., CLTC conditions). act This is the actual power consumption of the control unit.

[0105] Fig. shows a flowchart of steps S2 and S3 of the in Fig. The method shown. In this embodiment, step S2 comprises substeps S21 and S23, and step S3 comprises substeps S310-S320.

[0106] In Fig. The specific sequence of sub-steps S21 and S22 can be compared to the corresponding steps in Fig. It can be taken from the original text and will not be repeated here for the sake of simplicity.

[0107] In sub-step S23, the actual operating conditions of the slave control unit are recorded under each predefined operating condition within a predetermined time. Specifically, vehicle sensors can be used to record parameters of the driving environment (such as humidity, temperature, traffic flow, etc.) and vehicle status parameters (such as vehicle load, speed, acceleration, charging and discharging current, charging and discharging time, etc.). Furthermore, the system can access the internet via the appropriate communication interface, or external parameters (such as traffic conditions, the number of traffic lights on the road segment, weather conditions, etc.) can be received in real time based on vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communication.

[0108] In sub-step S310, the reference current consumption is corrected based on the deviation between the actual operating conditions and the reference operating conditions used in the offline determination of the reference current consumption. More precisely, a correction factor can be determined based on the deviation between the actual operating conditions and the reference operating conditions, and the reference current consumption can be corrected by superimposing the correction factor onto the reference current consumption. For example, correction factors can be determined based on the deviations between actual and reference operating conditions with respect to temperature, humidity, vehicle load, and / or road conditions.

[0109] In one embodiment, if the information on the actual operating conditions shows that the current ambient temperature is lower than the ambient temperature during the offline power consumption test, a correction factor can be calculated based on this temperature deviation. This correction factor is then added to the reference power consumption using the following formula: Pref,CLTC'=Pref,CLTC+Pref,CLTC×a

[0110] In, P ref,CLTC This is the uncorrected reference power consumption of the control unit under driving discharge conditions. P ref,CLTC'This is the corrected reference power consumption of the control unit under driving discharge conditions. This is a temperature-dependent correction factor. Such a correction would, for example, increase the offline measured reference current consumption, since low temperatures typically lead to lower efficiency of the components within the slave unit or to increased heating requirements, thereby increasing energy consumption.

[0111] In other embodiments, the correction factor can be determined based on a variety of other factors, such as humidity, vehicle load, speed, acceleration, charging and discharging current, road conditions, etc., and the combined effects of these factors on the reference current consumption can be weighted. Each factor can be assigned a different weight according to its actual influence on battery performance to ensure that the corrected reference current consumption more accurately reflects the energy consumption of the slave control unit under various preset operating conditions.

[0112] In sub-step S320, the actual power consumption can be determined based on the modified reference power consumption. This sub-step can be implemented, for example, as in sub-step S31. Fig.This can be demonstrated. For example, the actual power consumption of the slave unit under each preset operating condition can be calculated by multiplying the corrected reference power consumption by the actual operating time under the preset operating condition. Alternatively, the actual power consumption of the slave control unit can be calculated based on the percentage of time the slave control unit spends under the respective preset operating states within a predetermined period.

[0113] When calculating actual power consumption, the operating and standby states of the slave control unit under energy-saving conditions can be considered separately. For each of these two states, the actual operating time and the corresponding actual power consumption are recorded. Alternatively, this distinction can be omitted, and the actual operating time and power consumption can be recorded and calculated according to the operating mode category in each energy-saving operating state.

[0114] Although certain embodiments of the present invention are described in detail herein, they are provided for illustrative purposes only and are not to be regarded as limiting the scope of the present invention. Various substitutions, modifications, and variations may be conceived without departing from the spirit and scope of the present invention.

Claims

A method for estimating the state of charge of a battery (10), comprising the following steps: S1: Determining the reference current consumption of the slave control unit of the battery management system (20) connected to the battery (10), wherein the reference current consumption is determined offline; S2: Determining the actual operating state information of the slave control unit in the real operating scenario; S3: Determining the actual current consumption of the slave control unit based on the reference current consumption of the slave control unit and the information on the actual operating conditions; and S4: Estimating the state of charge of the battery (10) based on the actual current consumption of the slave control unit. The method of claim 1, wherein step S4 comprises: The main control unit (BCU) of the battery management system (20) estimates the rough state of charge of the battery (10) by integrating the charging and discharging current of the battery (10) over a predetermined period; and the rough state of charge is corrected based on the actual current consumption of the slave control unit to obtain the exact state of charge of the battery (10), and the exact state of charge is determined as the state of charge of the battery (10). The method of claim 1 or 2, wherein the information on the actual operating state includes the actual operating time of the slave control unit under each preset operating state within a predetermined period, and step S3 includes: calculating the actual power consumption of the slave control unit using a time-weighted method with the following formula: Pact = N × ∑i = 1 m ( Pref , i × ti ) where P act the actual power consumption of the control unit is P ref,i The reference power consumption of the slave control unit under the i-th preset operating condition is t i where is the actual operating time of the slave control unit under the i-th preset operating condition, and m is the number of preset operating conditions in which the slave control unit participates within a predetermined period. N is the number of slave control units (20) included in the battery management system. The method of claim 3, wherein step S2 comprises: the use of the battery management system (20) to determine the preset operating state of the slave control unit by monitoring the current direction, current intensity, type of charging interface and voltage of the battery (10), and the use of the timing chip of the battery management system (20) to record the actual working time of the slave control unit under the preset operating state. A method according to any one of claims 1 to 4, wherein the information on the actual operating state includes the actual operating state of the slave control unit under each preset operating state within a predetermined period, and step S3 includes: correcting the reference current consumption based on the deviation between the actual operating state and the reference current consumption used in the offline determination of the reference current consumption, and determining the actual current consumption based on the corrected reference current consumption. The method of claim 5, wherein step S3 comprises: determining a correction factor based on the deviation between the actual operating conditions and the reference operating conditions and correcting the reference current consumption by superimposing the correction factor onto the reference current consumption, wherein the correction factor is determined based on the deviation between the actual operating conditions and the reference operating conditions with respect to temperature, humidity, vehicle load and / or road conditions. A method according to any one of claims 3 to 6, wherein the preset operating conditions include normal operation and energy-saving operation. In normal operation, the slave control unit is permanently switched on; in energy-saving operation, it is either switched off or only switched on and off periodically; and / or the preset operating states include: DC charging state, AC charging state, driving discharge state, timed wake-up state, sleep balancing state, and full sleep state. Method according to claim 7, wherein the reference current consumption and / or the actual current consumption of the slave control unit under energy-saving conditions are determined as follows: For cases in which the slave control unit is in the operating state or in the non-operating state under energy-saving conditions, the reference current consumption and / or the actual current consumption of the slave control unit are determined separately. A method according to any one of claims 1 to 8, wherein step S1 comprises: Offline power consumption tests were performed on the actual slave control units in use and / or other slave control units under a series of preset operating conditions; and For each slave control unit tested offline, the average power consumption per unit of time is calculated under the respective preset operating conditions, and the reference power consumption is determined based on the average power consumption per unit of time.

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