Model predictive battery power limit estimation system and method

Abstract

Systems and methods for improving operation of an automotive battery system, the automotive battery system including an automotive electrical system that includes a battery system that uses operational parameters, a predicted internal resistance of the battery expected within a prediction horizon, and a real-time internal resistance of the battery to improve performance and reliability. The battery system includes a battery electrically coupled to an electrical device in the automotive system, a sensor coupled to the battery and determining a terminal voltage of the battery, and a battery control system communicatively coupled to the sensor. The battery control system determines a charge power limit for controlling a supply of power to the battery when charging the battery based on the predicted internal resistance when a measured terminal voltage of the battery is not greater than a lower voltage threshold, and based on the real-time internal resistance of the battery when the measured terminal voltage of the battery is greater than the lower voltage threshold.

Description

[0001] This application is a divisional application of the invention patent application with an international filing date of October 31, 2017, international application number PCT / US2017 / 059380, national application number 201780066095.9, and invention title "Model Prediction Battery Power Limit Estimation System and Method".

[0002] Cross-reference to related applications

[0003] This application is a non-provisional application that claims priority to U.S. Provisional Application No. 62 / 415,280, filed October 31, 2016, entitled “Integrating Feedback Control Algorithms with Alimetric Battery Model for Real-Time Power Limitation,” the entire contents of which are incorporated herein by reference for all purposes. Background Technology

[0004] This disclosure relates generally to battery systems, and more specifically to battery control systems used in battery systems.

[0005] This section aims to introduce the reader to various aspects of the technology that may relate to the aspects of the present technology described below and / or claimed. It is believed that this discussion will help provide the reader with background information to facilitate a better understanding of the various aspects of this disclosure. Therefore, it should be understood that these statements should be read in this light, and not as an admission of prior art.

[0006] Electrical systems typically include battery systems to capture (e.g., store) the electrical energy generated and / or supply power. In practice, battery systems can be included in electrical systems used for a wide variety of applications. For example, stationary power systems may include battery systems that receive power from a generator and store it as electrical energy. In this way, the battery system can use the stored electrical energy to supply power to electrical loads.

[0007] Additionally, the electrical system in a motor vehicle may include a battery system that supplies electricity, for example, to provide and / or supplement the vehicle's power (e.g., power). For the purposes of this disclosure, such motor vehicles are referred to as xEVs and may include any, any variant, and / or any combination of the following types of motor vehicles. For example, an electric vehicle (EV) may utilize a battery-powered electric propulsion system (e.g., one or more electric motors) as the primary source of vehicle power. Thus, the battery system in an electric vehicle can be implemented to supply electricity to the battery-powered electric propulsion system. Furthermore, a hybrid electric vehicle (HEV) may utilize a combination of a battery-powered electric propulsion system and an internal combustion engine propulsion system to generate vehicle power. Thus, a battery system can be implemented to directly provide at least a portion of the vehicle power by supplying electricity to the battery-powered electric propulsion system.

[0008] Mild hybrid electric vehicles (mHEVs) can use an internal combustion engine propulsion system as the primary power source, but can utilize a battery system to implement "stop-start" technology. Specifically, when propulsion is subsequently needed, the mHEV can deactivate its internal combustion engine while it is idling and crank-starting (e.g., restarting). To facilitate the implementation of these technologies, the battery system can continue to supply electricity when the internal combustion engine is deactivated, and supply electricity to crank-start the internal combustion engine. In this way, the battery system can indirectly supplement the vehicle's power supply.

[0009] To facilitate the control of battery system operation, battery systems typically include a battery control system, which determines battery states such as state of function (SoF), state of health (SoH), and / or state of charge (SoC). In some cases, the charging and / or discharging of a battery (e.g., a battery module, battery pack, or battery cell) can be controlled at least in part based on the corresponding battery state determined by the battery control system. For example, the magnitude of the current and / or voltage supplied for charging the battery can be controlled at least in part based on the charging power limit indicated by its corresponding state of function. Therefore, at least in some cases, the accuracy of the battery state determination made by the battery control system may affect the operational stability and / or operational efficiency of the corresponding battery system. Summary of the Invention

[0010] An overview of certain embodiments disclosed herein is provided below. It should be understood that these aspects are provided merely to give the reader a brief overview of these particular embodiments, and these aspects are not intended to limit the scope of this disclosure. In fact, this disclosure may cover aspects that may not be set forth below.

[0011] In one embodiment, the automotive electrical system includes a battery system comprising a battery, one or more sensors, and a battery control system. The battery is configured to be electrically coupled to one or more electrical devices in the automotive electrical system, the sensors are electrically coupled to the terminals of the battery, and the battery control system is communicatively coupled to the one or more sensors that measure the terminal voltage of the battery. The battery control system is programmed to determine a predicted internal resistance of the battery, wherein the predicted internal resistance is based on anticipated operating conditions (state of charge, temperature, power usage, etc.). When the measured terminal voltage of the battery is not greater than a lower voltage threshold, the battery control system also determines a charging power limit for controlling the supply of power to the battery based on the predicted internal resistance. When the measured terminal voltage of the battery is greater than the lower voltage threshold, the battery control system determines the real-time internal resistance of the battery based on the measured terminal voltage and a battery model describing the relationship between the measured battery parameters and the battery's internal resistance, and determines the charging power limit based on the real-time internal resistance to improve the operational reliability of the battery.

[0012] In a second embodiment, a method for controlling the charging of a battery cell in a motor vehicle includes using a control system to determine a measured terminal voltage of the battery cell based on sensor data, a predicted internal resistance of the battery cell, and a charging power limit. The predicted internal resistance is based on anticipated operating conditions (state of charge, temperature, power usage, etc.). When the measured terminal voltage of the battery cell is not greater than a lower voltage threshold, the charging power limit is based on the predicted internal resistance of the battery cell. When the measured terminal voltage of the battery cell is greater than the lower voltage threshold, the charging power limit is based on the real-time internal resistance of the battery cell, wherein the real-time internal resistance of the battery cell is determined based on a battery model that correlates measured operating parameters with model parameters including the internal resistance. When the target charging power is greater than the charging power limit, the control system instructs a power source to adjust the charging power supplied to the battery cell based on the charging power limit.

[0013] In a third embodiment, a tangible, non-transitory computer-readable medium stores instructions executable by one or more processors of the vehicle control system. The instructions include using one or more processors to determine a measured terminal voltage of the vehicle battery module based on sensor data, a predicted internal resistance of the vehicle battery module expected to occur within a predicted range, and a charging current limit, and instructing the vehicle battery to supply power to electrical devices in the motor vehicle based on a discharging current limit. When the measured terminal voltage of the vehicle battery module is not greater than a lower voltage threshold, the discharging current limit is based on the predicted internal resistance of the vehicle battery module. When the measured terminal voltage of the vehicle battery module is greater than the lower voltage threshold, the discharging limit is based on the real-time internal resistance of the vehicle battery module. The real-time internal resistance of the vehicle battery module is determined by a battery model that correlates measured battery parameters with model parameters including the internal resistance. Attached Figure Description

[0014] A better understanding of the various aspects of this disclosure can be achieved by reading the following detailed description and referring to the accompanying drawings, in which:

[0015] Figure 1 This is a perspective view of a motor vehicle including a battery system according to an embodiment;

[0016] Figure 2 According to the embodiments Figure 1 A block diagram of the battery system;

[0017] Figure 3 According to the embodiments, by Figure 1 The circuit diagram of the battery model used in the battery system;

[0018] Figure 4 It is for operation according to the embodiment Figure 1 A flowchart of the battery system process;

[0019] Figure 5 It is used to determine according to the embodiments. Figure 1 A flowchart of the process of determining the operating parameters of the battery in the battery system;

[0020] Figure 6 It is used to determine according to the embodiments. Figure 1 A flowchart of the battery state process in a battery system; and

[0021] Figure 7 It is for control according to the embodiment. Figure 1 A flowchart of the battery charging process in a battery system. Detailed Implementation

[0022] One or more specific embodiments of this disclosure will now be described. These described embodiments are merely examples of the technology of this disclosure. Furthermore, to provide a concise description of these embodiments, not all features of an actual implementation may be described in the specification. It should be understood that in the deployment of any such actual implementation, as in any engineering or design project, many decisions must be made specifically for the implementation to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which may vary from implementation to implementation. Furthermore, it should be understood that such deployment work can be complex and time-consuming, but can still be routine tasks of design, preparation, and manufacture for those skilled in the art who benefit from this invention.

[0023] When describing elements of various embodiments of this disclosure, the articles “a,” “an,” and “the” are intended to indicate the presence of one or more such elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that other elements besides those listed may be present. Furthermore, it should be understood that references to “an embodiment” or “an embodiment” in this disclosure are not intended to be construed as excluding other embodiments that also include the described features.

[0024] Typically, a battery system can be implemented to capture (e.g., store) electrical energy generated by one or more generators and / or use the stored electrical energy to supply electrical energy to one or more electrical loads. Taking advantage of these benefits, electrical systems often include one or more battery systems. In practice, battery systems can be used in electrical systems implemented for a wide range of target applications, from stationary power systems to vehicle (e.g., automobile) electrical systems.

[0025] In any case, a battery system typically includes a battery control system to facilitate control of its operation (e.g., charging and / or discharging). In some cases, the charging and / or discharging of the batteries (e.g., battery modules, battery packs, or battery cells) within the battery system can be controlled, at least in part, based on the corresponding battery state, for example, through coordination with a higher-level (e.g., vehicle) control system. Therefore, to facilitate the control of the battery system's operation, its battery control system can determine the battery state by performing control applications at least in part based on the battery's operating parameters (e.g., voltage, current, and / or temperature).

[0026] For example, based at least in part on the current flowing through the battery, the battery control system can perform a state-of-charge (SoC) application to determine (e.g., predict or estimate) the battery's open-circuit voltage (OCV). Alternatively, based at least in part on the battery's current and / or voltage, the battery control system can perform a state-of-health (SoH) application to determine the battery's internal resistance. Alternatively, based at least in part on the battery's temperature and / or internal resistance, the battery control system can perform a state-of-function (SoF) application to determine limits on the electrical (e.g., voltage and / or current) required for charging and / or discharging the battery.

[0027] Based at least in part on the battery state, in some cases, the battery control system can directly control the operation of the corresponding battery system by outputting control commands (e.g., signals) instructing the battery system to perform one or more control actions. For example, the battery control system can output a control command that instructs a switching device electrically coupled between the battery and a generator (e.g., an alternator) in the battery system to switch from a closed (e.g., electrically connected) position to an open (e.g., electrically disconnected) position when the battery's state of charge exceeds a state of charge threshold. Alternatively or additionally, the battery control system can facilitate control of the operation of the corresponding battery system by transmitting battery state data to a higher-level control system implemented to control the operation of one or more devices (e.g., equipment or machines) outside the battery system. For example, based at least in part on data indicating the battery's functional state, the vehicle control unit can output a control command that instructs the alternator to adjust the current and / or voltage of the power output to the battery system.

[0028] To facilitate improvements in battery system operation, in some cases, the battery control system may predict (e.g., estimate) the battery state, at least in part, based on operating parameters determined through a battery (e.g., battery pack or battery cell) model, for example, to facilitate selection among candidate control strategies (e.g., actions). In other words, the battery control system may determine the modeled (e.g., predicted) operating parameters of the battery system, at least in part, based on the battery model. Alternatively or additionally, the battery control system may determine the measured (e.g., real-time) operating parameters of the battery system, at least in part, based on sensor data received from one or more sensors.

[0029] Therefore, at least in some cases, the operation of a battery system can be controlled in different ways in response to different battery states and / or different operating parameters. Consequently, when the operation of a battery system is controlled based on a predicted battery state determined by its battery control system, the accuracy of the predicted battery state relative to the corresponding real-time battery state and / or the accuracy of the modeled operating parameters relative to the corresponding measured operating parameters can affect the operational reliability and / or operational efficiency of the battery system. For example, supplying power to the battery according to the determined charging power limit when the actual charging power is greater than the limit can reduce subsequent lifespan, thereby reducing battery reliability. Alternatively, when the actual charging state is less than the limit, disconnecting the power used to charge the battery based on the determined charging state can reduce the amount of captured energy, thereby reducing the operational efficiency of the battery system.

[0030] In some cases, the modeled operating parameters of a battery system may differ from the measured operating parameters, for example, due to inaccuracies in the battery model. Therefore, the predicted (e.g., modeled) battery state determined based on the modeled operating parameters may also differ from the real-time (e.g., measured) battery state determined based on the measured operating parameters. Furthermore, in some cases, the modeled battery state and the measured battery state may differ due to inaccuracies in the corresponding control applications. At least in some cases, when such discrepancies occur, control operation may affect the operational reliability and / or efficiency of the battery system, for example, by causing the battery modules to be electrically disconnected before being charged to a state-of-charge threshold, thereby limiting the energy storage provided by the battery system and / or the battery system's ability to subsequently crank-start the internal combustion engine.

[0031] Therefore, this disclosure provides techniques to facilitate improved operation of battery systems, for example, by improving the accuracy of online (e.g., real-time or near-real-time) battery state determination. To facilitate online battery state determination, the battery control system can receive sensor data indicating operating parameters of the batteries (e.g., battery modules or battery cells) implemented in the battery system. For example, during operation of the battery system, the battery control system can receive sensor data indicating the temperature of the battery module, the current flowing through the battery module, the terminal voltage of the battery module, and / or the voltage across one or more battery cells within the battery module.

[0032] In some embodiments, battery life can be extended by keeping the battery terminal voltage below an upper voltage threshold (e.g., a maximum voltage threshold). To reduce the likelihood that sensor (e.g., measurement) errors will cause the terminal voltage to exceed the upper voltage threshold, in some embodiments, the battery control system may begin to reduce the battery system rating before the battery terminal voltage reaches the upper voltage threshold. For example, the battery control system may limit the current and thus limit the charging power supplied to the battery, at least in part, based on the relationship (e.g., the difference) between the terminal voltage and the lower voltage threshold.

[0033] In some embodiments, the battery control system may determine the power limits for charging and / or discharging the battery based at least in part on the battery's internal resistance. Typically, the internal resistance of a battery is dynamic during operation and throughout its lifespan. For example, the internal resistance of a lithium-ion battery may increase as the battery ages. Additionally, the internal resistance of a lithium-ion battery may be inversely proportional to its temperature. Furthermore, the internal resistance of a lithium-ion battery may fluctuate (e.g., spike) during operation, for example, when the lithium-ion battery is charged during regenerative braking or discharged during start-stop operation.

[0034] To facilitate consideration of dynamic characteristics, in some embodiments, the battery control system can predict the battery's internal resistance within a predicted range (e.g., a time period) based on anticipated operating conditions (state of charge, temperature, power usage, etc.). Typically, controlling the battery's charging and / or discharging according to a power limit determined at least in part based on its predicted internal resistance is sufficient to maintain the battery voltage below a voltage threshold upper limit. However, in certain situations (e.g., extreme cases), such control of the battery operation may affect the battery system's operating efficiency, as the difference between the predicted and actual internal resistance can cause rapid oscillations in the battery voltage (without a properly designed control algorithm). Indeed, when implemented in motor vehicles, such battery voltage oscillations can affect drivability, for example, by causing the vehicle to tilt while in motion.

[0035] To mitigate the likelihood of rapid battery voltage oscillations, in some embodiments, the battery control system can determine the real-time (e.g., instantaneous) internal resistance based at least in part on currently determined (e.g., measured) operating parameters. For example, using a battery model, the battery control system can determine the battery's real-time internal resistance based at least in part on currently determined battery current and terminal voltage. Because the real-time internal resistance is determined based on currently determined operating parameters, it can more accurately represent the actual internal battery resistance at a specific point in time, at least in some cases, compared to a predicted internal resistance averaged over a longer period.

[0036] However, to facilitate improvements in processing latency, battery control systems typically determine power limits based on predicted internal resistance. However, when charging and / or discharging based on predicted internal resistance is expected to cause rapid battery voltage oscillations, power limits are determined based on real-time internal resistance. In some embodiments, the battery control system may determine the likelihood of rapid battery voltage oscillations based at least in part on the battery's terminal voltage. For example, when the terminal voltage is greater than a lower voltage threshold, the battery control system may determine to use a charging power limit determined based on predicted internal resistance to control charging from causing rapid battery voltage oscillations, and thus determine the charging power limit based on real-time internal resistance.

[0037] By determining the charging and / or discharging power limits in this manner, the battery control system can improve the accuracy of its functional state determination. Similarly, the battery control system can additionally or alternatively improve the accuracy of other battery state determinations. As stated above, at least in some cases, improving the accuracy of the battery states determined by the battery control system and used to control the operation of the corresponding battery system contributes to improving the operational reliability and / or efficiency of the battery system, and thus the operational reliability and / or efficiency of the electrical systems in which the battery system is implemented.

[0038] To help illustrate, Figure 1 A motor vehicle 10 with an electrical system, including a battery system 12, is illustrated. The discussion of the motor vehicle 10 is intended only to aid in the illustration of the technology of this disclosure and not to limit the scope of the technology. The motor vehicle 10 may include the battery system 12 and a vehicle electrical system that controls a vehicle console, electric motor, and / or generator. In some cases, the battery system 12 may include some or all of the vehicle electrical system. For ease of discussion, the battery system 12 is electrically coupled to components in the vehicle electrical system under discussion. In some embodiments, the motor vehicle 10 may be an xEV that utilizes the battery system 12 to provide and / or supplement vehicle power, for example, for accelerating and / or decelerating the motor vehicle 10. In other embodiments, the motor vehicle 10 may be, for example, a motor vehicle 10 that uses an internal combustion engine to generate vehicle power for acceleration and / or uses friction brakes for deceleration.

[0039] Figure 2 A more detailed view of an exemplary automotive electrical system is shown, which includes a battery system 12. In the depicted example, the battery system 12 includes a battery control system 14 and one or more battery modules 16. Additionally, the automotive electrical system may include a vehicle console 18 and a heating, ventilation, and air conditioning (HVAC) system 20. In some embodiments, the automotive electrical system may additionally or alternatively include a mechanical energy source 22 (e.g., an electric motor) operating in motor mode.

[0040] Additionally, in the depicted motor vehicle 10, the vehicle electrical system may include a power source. In the illustrated example, the power source in the vehicle electrical system is an alternator 24. The alternator 24 can convert mechanical energy generated by a mechanical energy source 22 (e.g., an internal combustion engine and / or rotating wheels) into electrical energy. In some embodiments, the power source may additionally or alternatively include a mechanical energy source 22 (e.g., an electric motor) operating in generator mode.

[0041] As shown in the figure, the motor vehicle 10 includes a vehicle control system 26. In some embodiments, the vehicle control system 26 can generally control the operation of the motor vehicle 10, including the electrical system. Thus, in the depicted motor vehicle 10, the vehicle control system 26 can supervise the battery control system 14, battery module 16, HVAC 20, alternator 24, vehicle console 18, and / or mechanical energy source 22, making the vehicle control system 26 resemble a supervisory control system. However, the vehicle control system 26 can additionally control the operation of components other than those in the electrical system, such as the internal combustion engine propulsion system.

[0042] In some embodiments, the battery control system 14 may additionally or alternatively control the operation of the battery system 12. For example, the battery control system 14 may determine the operating parameters of the battery modules 16, coordinate the operation of multiple battery modules 16, transmit control commands (e.g., signals) to instruct the battery system 12 to perform control actions, and / or communicate with the vehicle control system 26.

[0043] To facilitate control of the operation of the battery system 12, the battery control system 14 may include a processor 28 and a memory 30. In some embodiments, the memory 30 may include a tangible, non-transitory computer-readable medium storing data, such as instructions executable by the processor 28, results determined by the processor 28 (e.g., battery state), and / or information to be analyzed / processed by the processor 28 (e.g., operating parameters). Therefore, in such embodiments, the memory 30 may include random access memory (RAM), read-only memory (ROM), rewritable non-volatile memory (e.g., flash memory), hard disk drive, optical disk, etc. Additionally, the processor 28 may include one or more general-purpose processing units, processing circuitry, and / or logic circuitry. For example, the processor 28 may include one or more microprocessors, one or more application-specific integrated circuits (ASICs), and / or one or more field-programmable logic arrays (FPGAs).

[0044] Additionally, to facilitate power storage and supply, the battery system 12 may include one or more battery modules 16. In some embodiments, the storage capacity of the battery system 12 may be based at least in part on the number of battery modules 16. Furthermore, in some embodiments, the operational compatibility of the battery system 12 with the vehicle's electrical system may be based at least in part on the configuration of the battery modules 16 (e.g., series and / or parallel) to operate in a target voltage domain. Therefore, in some embodiments, the implementation (e.g., number and / or configuration) of the battery modules 16, and thus the battery system 12, may vary at least in part based on the configuration of the vehicle's electrical system and / or the target application.

[0045] As described above, the number and / or configuration of the battery modules 16 in the battery system 12 may vary at least in part based on the target application. For example, in the depicted motor vehicle 10, the battery system 12 includes battery modules 16. In some embodiments, the battery modules 16 may include one or more battery cells 32 connected in series and / or in parallel with the terminals of the battery modules 16.

[0046] Additionally, in some embodiments, the battery system 12 may include multiple battery modules 16 to improve application flexibility and / or ease of use. For example, the battery system 12 may include a first battery module 16 and a second battery module 16, each of which includes one or more battery cells 32 connected in series and / or in parallel. Note that the battery system 12 may include multiple battery modules 16 to ensure operational compatibility with multiple voltage domains. For example, the first battery module 16 may operate (e.g., receive and / or supply power) using power from a first (e.g., high or 48 volts) voltage domain, while the second battery module 16 may operate using power from a second (e.g., low or 12 volts) voltage domain.

[0047] In any case, the battery control system 14 can be communicatively coupled to one or more sensors 34 to facilitate overall monitoring of the operation of the battery module 16 or battery system 12. Specifically, the sensors 34 can transmit sensor data to the battery control system 14, the sensor data indicating real-time (e.g., measured) operating parameters of the battery module 16. Therefore, in some embodiments, the battery control system 14 can be communicatively coupled to one or more voltage sensors 34, one or more temperature sensors 34, and / or various additional or alternative sensors 34. For example, in the illustrated embodiment, the battery control system 14 can receive sensor data from the sensors 34 indicating the voltage (e.g., terminal voltage) of the battery module 16 and / or the current flowing through the battery module 16.

[0048] In some embodiments, the battery control system 14 may process sensor data based on instructions stored in the memory 30. For example, the battery control system 14 may store the battery model 42 and control application 44 as instructions in the memory 30. As described above, the battery control system 14 may execute the control application 44 to determine the state of the batteries (e.g., battery module 16 and / or battery cell 32) in the battery system 12. For example, the battery control system 14 may execute the functional state control application 44 to determine discharge current limits and / or charging current limits based at least in part on the battery terminal voltage. Additionally, based at least in part on the battery state, the battery control system 14 may instruct the battery system 12 to perform one or more control actions and / or operate in a different manner. For example, when the discharge current flowing through the switching device exceeds the discharge current limit stored in the memory 30, the battery control system 14 may instruct the switching device to switch from a closed (e.g., connected) position to an open (e.g., disconnected) position.

[0049] Additionally, in some embodiments, the battery control system 14 can use the battery model 42 to predict the operation of the battery and / or battery system 12. In other words, the battery model 42 can model the behavior of the battery system 12, the behavior of one or more battery cells 32, and / or the behavior of one or more battery modules 16. Therefore, in some embodiments, the memory 30 can store one or more different battery models 42, for example, to model the operation at different levels of abstraction and / or to model the operation of batteries using different battery chemistry compositions. In any case, the battery model 42 is generally computationally simple while having high predictive accuracy to facilitate real-time control.

[0050] Typically, the battery control system 14 can use the battery model 42 to predict battery operating parameters as an addition to or alternative to the operating parameters measured by the sensors 34. Specifically, the battery control system 14 can input one or more operating parameters into the battery model 42, and the battery model 42 can output one or more predicted operating parameters, at least in part based on the interrelationships of these operating parameters. For example, the battery control system 14 can determine the battery's terminal voltage using the sensors 34, and using the terminal voltage in the battery model 42, the battery control system 14 can determine the battery's open-circuit voltage 60. In this way, the battery control system 14 can utilize the battery model 42 to determine (e.g., predict) the battery's behavior, which, at least in some cases, can facilitate a reduction in the implementation-related costs of the battery system 12, for example, by reducing the number of sensors 34.

[0051] Figure 3 An example of a battery model 42 is shown, which the battery control system 14 can use to model the operation of the battery. As shown, the battery model 42 uses an RC equivalent circuit model. In this way, the battery model 42 can represent one or more individual battery cells 32 and / or one or more battery modules 16. The battery model 42 correlates model parameters (e.g., resistors 56, 58, and capacitor 62) with operating parameters (e.g., terminal voltage 54, terminal current, and battery temperature) measured by one or more sensors 34. In addition, the battery model 42 can provide a mechanism for estimating parameters of the battery model 42 (e.g., open-circuit voltage 60) in real time during operation of the motor vehicle 10.

[0052] In battery model 42, resistor 58 (e.g., R0) can represent the ohmic resistance of the current path of battery module 16, resistor 56 (e.g., R1) can represent the charge transfer resistance of battery module 16, and capacitor 62 (e.g., C1) can represent the double-layer capacitor of battery module 16. In battery model 42, resistors 56 and 58, and capacitor 62, can typically be time-invariant parameters of battery module 16. Additionally, the open-circuit voltage 60 used to determine the state of battery module 16 can typically be a time-varying parameter. That is, as battery module 16 charges and discharges over time, open-circuit voltage 60 can increase and decrease over time. In this way, due to the dependence of parameter values ​​on model parameters, the accuracy of battery model 42, and subsequently the accuracy of the open-circuit voltage 60 parameter, can be improved by verifying the model parameters. In any case, as described above, battery control system 14 can be at least partially based on battery model 42 and / or one or more control applications 44 to facilitate the control of the operation of the corresponding battery system 12.

[0053] To help illustrate, Figure 4 An example of a process 70 for controlling the operation of battery system 12 is shown. Typically, process 70 includes determining operating parameters of the battery (process block 72), determining the battery state based on the operating parameters (process block 74), and controlling the charging and / or discharging of the battery based on the battery state (process block 76). In some embodiments, process 70 may be implemented at least in part by using processing circuitry (such as processor 28) to execute instructions stored in a tangible, non-transitory computer-readable medium (such as memory 30).

[0054] Therefore, in some embodiments, the battery control system 14 can determine the battery's operating parameters (process block 72). Figure 5 An example of a process 86 for determining the operating parameters of a battery is described herein. Typically, process 86 includes determining the current flowing through the battery (process block 88), determining the terminal voltage of the battery (process block 90), and determining the temperature of the battery (process block 92). In some embodiments, process 86 may be implemented at least in part by using processing circuitry (such as processor 28) to execute instructions stored in a tangible, non-transitory computer-readable medium (such as memory 30).

[0055] Therefore, in some embodiments, the battery control system 14 may determine the battery's operating parameters at least in part based on sensor data (e.g., signals) received from one or more sensors 34. For example, the battery control system 14 may determine the battery's terminal voltage 54 at least in part based on sensor data received from a first (e.g., voltage) sensor 34 (process block 88). Additionally, the battery control system 14 may determine the current flowing through the battery at least in part based on sensor data received from a second (e.g., current) sensor 34 (process block 90). Furthermore, the battery control system 14 may determine the battery's temperature at least in part based on sensor data received from a third (e.g., temperature) sensor 34 (process block 92).

[0056] In this way, the battery control system 14 can determine operating parameters, including the battery terminal voltage, current, and / or temperature. As described above, different battery models 42 can be used to model the operation of different batteries. At least in some cases, the operating parameters used in different battery models 42 can vary. For example, one battery model 42 may use a first set of operating parameters, while different battery models 42 may use a second set of operating parameters.

[0057] Therefore, in some embodiments, the battery control system 14 can at least partially change determined operating parameters based on operating parameters intended to be used in the battery model 42 and / or operating parameters intended to be used in the control application 44. For example, when the battery control system 14 uses Figure 3 When using the battery model 42 described herein, determining the terminal voltage and current may be sufficient. However, in some embodiments, the battery control system 14 may still determine the battery temperature, as the execution of the control application 44 may depend on the battery temperature.

[0058] Return to Figure 4 In process 70, at least in part based on the battery's operating parameters, the battery control system 14 can determine the battery state (process block 74). Figure 6An example of a process 94 for determining one or more battery states is described herein. Typically, process 94 includes determining the open-circuit voltage of the battery (process block 96), determining the predicted internal resistance of the battery (process block 98), determining whether the terminal voltage of the battery is greater than a voltage threshold (decision block 100), and determining a charging power limit based on the predicted internal resistance when the terminal voltage is not greater than the voltage threshold (process block 102). When the terminal voltage is greater than the voltage threshold, process 94 includes determining the real-time internal resistance of the battery (process block 104) and determining a charging power limit based on the real-time internal resistance of the battery (process block 106). In some embodiments, process 94 may be implemented at least in part by using processing circuitry (such as processor 28) to execute instructions stored in a tangible, non-transitory computer-readable medium (such as memory 30).

[0059] Therefore, in some embodiments, the battery control system 14 can determine (e.g., predict or estimate) the battery's open-circuit voltage 60 (process block 96) based at least in part on the battery's operating parameters. Typically, the battery's open-circuit voltage 60 can vary with its state of charge. Therefore, in some embodiments, the battery control system 14 can execute a state of charge control application 44 to facilitate the determination of the open-circuit voltage 60. For example, by executing the state of charge control application 44, the battery control system 14 can determine the state of charge based at least in part on the current previously flowing through the battery (e.g., using coulomb counting techniques). Utilizing their interrelationships, the battery control system 14 can then determine the battery's open-circuit voltage 60 based at least in part on its state of charge.

[0060] Additionally, the battery control system 14 can determine the predicted internal resistance of the battery (process block 98). In some embodiments, the battery control system 14 predicts the expected internal resistance based on anticipated operating conditions (state of charge, temperature, power usage, etc.). For example, the battery control system 14 can determine the predicted internal resistance based at least in part on the predicted driving mode, the current flowing through the battery, and the battery terminal voltage 54. In such embodiments, the predicted internal resistance can be determined using the following relationship (e.g., a model):

[0061]

[0062] Where R is the predicted internal resistance, ΔV is the difference between the current (e.g., real-time) terminal voltage and the estimated open-circuit voltage, and I is the value of the current battery current. In this way, the battery control system 14 can determine the predicted internal resistance of the battery by properly taking into account charging and / or discharging over time.

[0063] When the battery terminal voltage 54 is greater than a voltage threshold, the battery control system 14 can determine the battery's real-time internal resistance (process block 104). In some embodiments, the voltage threshold may be predetermined and stored in a tangible, non-transitory computer-readable medium (such as memory 30). Thus, in such embodiments, the battery control system 14 can retrieve the voltage threshold from the tangible, non-transitory medium for comparison with the terminal voltage 54.

[0064] Additionally, as mentioned above, battery life may decrease when the battery terminal voltage increases above the upper voltage threshold. To reduce the possibility of sensor or measurement errors causing the actual terminal voltage to exceed the upper voltage threshold, in some embodiments, the battery may begin to reduce its rating, for example, by limiting the charging and / or discharging of the battery, before its measured terminal voltage 54 reaches the upper voltage threshold. For example, the battery control system 14 may reduce the battery rating based at least in part on a comparison between its measured terminal voltage 54 and the lower voltage threshold.

[0065] Therefore, when the measured terminal voltage is greater than the lower limit of the voltage threshold, the battery control system 14 can determine the real-time internal resistance of the battery, at least in part, based on the battery model 42. For example, using Figure 4 The battery model 42 shown, and the battery control system 14, can determine the real-time internal resistance of the battery (e.g., the combined resistance of resistors 58, 56, and / or capacitor 62) based at least in part on its open-circuit voltage 60, a measured (e.g., current or real-time) terminal voltage 54, and a measured (e.g., current or real-time) battery current. Specifically, the real-time internal resistance can be equal to the difference between the measured terminal voltage 54 and the open-circuit voltage 60 divided by the measured battery current.

[0066] Based at least in part on real-time or predicted internal resistance, the battery control system 14 can determine charging power limits. Typically, different charging powers supplied to the battery may involve different trade-offs. For example, increasing the charging power increases the energy stored in the battery, but also increases the battery temperature, which can lead to reduced battery life. On the other hand, reducing the charging power (e.g., lowering the rating) facilitates lowering the battery temperature, but also reduces the energy stored in the battery. Therefore, to facilitate balancing these trade-offs, the battery control system 14 can execute (e.g., functional state) control applications 44 to determine the charging power limits.

[0067] Specifically, when the measured terminal voltage 54 is greater than the lower voltage threshold, the battery control system 14 can use the real-time internal resistance to execute control application 44 to determine the battery's charging power limit (process block 106). As mentioned above, since the internal resistance is typically dynamic (e.g., varies over time), the real-time internal resistance can, for example, represent the actual internal resistance at a specific moment more accurately than the predicted internal resistance. In other words, determining the charging power limit in this way, at least in some cases, facilitates achieving a target balance between various trade-offs, such as reducing the likelihood of rapid terminal voltage oscillations.

[0068] On the other hand, when the battery terminal voltage 54 is not greater than the lower voltage threshold, the battery control system 14 can use the predicted internal resistance to execute control application 44 to determine the battery's charging power limit (process block 102). As mentioned above, the predicted internal resistance can be predicted within a predicted range and therefore can be applied to more than one specific moment. In practice, although the real-time internal resistance can more accurately represent the internal resistance at a specific moment, the accuracy of the predicted internal resistance is generally sufficient to determine the charging power limit during its predicted range. Therefore, determining the charging power limit in this way by utilizing the terminal voltage as a dividing indicator between these moments can facilitate improved processing efficiency of the battery control system 14, for example, by reducing the number of times the real-time internal resistance is determined.

[0069] Return to Figure 4 Process 70, at least in part based on the state of the battery, allows the battery control system 14 to facilitate the control of battery charging and / or discharging, for example, in cooperation with a higher-level (e.g., vehicle) control system (process block 76). For further illustration, Figure 7 An example of a process 108 for controlling battery charging is described herein. Typically, process 108 includes determining a target charging power (process block 110), determining whether the target charging power is less than a charging power limit (determination block 112), supplying power at the target charging power when the target charging power is less than the charging power limit (process block 114), and supplying power at the charging power limit when the target charging power is not less than the charging power limit (process block 116). In some embodiments, process 108 may be implemented at least in part by using processing circuitry (such as processor 28) to execute instructions stored in a tangible, non-transitory computer-readable medium (such as memory 30).

[0070] Therefore, in some embodiments, the control system (e.g., battery control system 14 and vehicle control system 26) can determine the target charging power (process block 110). As mentioned above, different charging powers can affect the amount of electrical energy stored in the battery, thereby affecting the battery's subsequent ability to supply power to electrical devices. Therefore, in some embodiments, the battery control system 14 can determine the target charging power based at least in part on a target state of charge obtained through the charging operation. Additionally or alternatively, the battery control system 14 can determine the target charging power based at least in part on an electrical device to which the battery is expected to subsequently supply power.

[0071] Based on a comparison between the target charging power and the charging power limit, the control system can instruct the power source (e.g., an alternator or generator) to adjust the power supplied to the battery. Specifically, when the target charging power is less than the charging power limit, the control system can instruct the power source to supply power to the battery according to the target charging power. Conversely, when the target charging power is not less than the charging power limit, the control system can instruct the power source to supply power to the battery according to the charging power limit, thereby improving the battery's operational reliability. For example, by reducing the likelihood that charging operations will significantly affect (e.g., shorten) the battery's subsequent lifespan.

[0072] Therefore, one or more of the disclosed embodiments, individually or in combination, can provide one or more technical effects, including improved battery system performance. In particular, the disclosed embodiments can determine power limits for charging and / or discharging the battery by executing control applications, such as based on voltage, current, temperature, state of charge, battery cells, and operating parameters. For example, by using battery state predicted at least in part based on operating parameters determined by a battery model, the battery control system can estimate the power limits used when outputting control commands (e.g., switching the generator from a closed position to an open position). Additionally or alternatively, the battery control system can determine real-time (e.g., measured or actual) operating parameters of the battery system based at least in part on sensor data received from one or more sensors. In this way, the techniques described herein enable improved accuracy in online (e.g., real-time or near-real-time) battery state determination. The technical effects and problems described in the specification are exemplary and not limiting. It should be noted that the embodiments described in the specification can have other technical effects and can solve other technical problems.

[0073] The specific embodiments described above have been illustrated by way of example, and it should be understood that these embodiments are permissible with various modifications and alternatives. It should also be understood that the claims are not intended to limit the specific forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims

1. A battery system, comprising: The battery includes terminals for electrical coupling to an electrical system; One or more sensors, electrically coupled to the battery and configured to determine sensor data indicating measured operating parameters of the battery, including measured terminal voltages; and A battery control system, communicatively coupled to the one or more sensors, is programmed to: Determine the predicted internal resistance of the battery within the predicted range; Determine the real-time internal resistance of the battery within the predicted range; When the measured terminal voltage of the battery is less than the lower voltage threshold, a charging power limit is determined based on the predicted internal resistance, and the charging power limit is used to control the power supply to the battery. and When the measured terminal voltage of the battery is greater than the lower voltage threshold, the charging power limit is determined based on the real-time internal resistance.

2. The battery system of claim 1, wherein the predicted internal resistance is determined when the measured terminal voltage of the battery is less than the lower voltage threshold and wherein the real-time internal resistance is determined when the measured terminal voltage of the battery is greater than the lower voltage threshold.

3. The battery system of claim 1, wherein the predicted internal resistance is determined based on the expected operating conditions within the predicted range.

4. The battery system of claim 1, wherein the real-time internal resistance is determined based on the measured terminal voltage of the battery and a battery model, the battery model describing the relationship between the measured battery parameters and the internal resistance of the battery.

5. The battery system according to claim 1, wherein the battery control system is further programmed to: When the measured terminal voltage of the battery is less than the lower voltage threshold, the charging of the battery is controlled using the charging power limit determined based on the predicted internal resistance; and When the measured terminal voltage of the battery is greater than the lower voltage threshold, the charging of the battery is controlled using the charging power limit determined based on the real-time internal resistance.

6. The battery system according to claim 1, wherein: The one or more sensors are configured to determine sensor data indicating a measured current flowing through the battery; and To determine the real-time internal resistance, the battery control system is further programmed to: Determine the open-circuit voltage of the battery; and The real-time internal resistance of the battery is determined by dividing the difference between the measured terminal voltage and the open-circuit voltage of the battery by the measured current flowing through the battery.

7. The battery system according to claim 6, wherein, To determine the open-circuit voltage of the battery, the battery control system is further programmed to: Determine the initial state of charge of the battery; The current state of charge of the battery is determined based on the current flowing through the battery between the initial state of charge and the current state of charge. as well as The open-circuit voltage of the battery is determined based on the battery's current state of charge.

8. The battery system according to claim 6, wherein, To determine the open-circuit voltage of the battery, the battery control system is further programmed to: The battery system is instructed to electrically disconnect the battery from one or more electrical devices of the electrical system; and After the battery remains electrically disconnected from the one or more electrical devices for a duration greater than a dormant duration threshold, the open-circuit voltage of the battery is determined based on the measured terminal voltage.

9. The battery system according to claim 1, wherein: The one or more sensors are configured to determine sensor data indicating a measured current passing through the battery.

10. The battery system of claim 4, comprising a temperature sensor configured to determine sensor data indicating the temperature of the battery, wherein the battery control system is programmed to adjust model parameters of the battery model based on the temperature of the battery.

11. An electrical system comprising: The battery system according to claim 1; Electrically coupled to the power source and electrical load at the terminals of the battery; as well as An electrical control system, communicatively coupled to the battery control system and the power source, wherein the electrical control system is programmed to: Receive the indication of the charging power limit from the battery control system; as well as The power source is instructed to supply power to the battery according to the charging power limit.

12. The electrical system of claim 11, wherein the battery control system is programmed to instruct the battery system to electrically disconnect the battery from the electrical load when the measured terminal voltage of the battery exceeds an upper voltage threshold, wherein the upper voltage threshold is greater than the lower voltage threshold, so as to extend the battery's service life.

13. A method for controlling the charging of a battery in an electrical system, comprising: The control system determines the measured terminal voltage of the battery based on sensor data received from the first sensor. Using the control system, the predicted terminal voltage of the battery expected to occur within the predicted range is determined by making predictions based on the measured terminal voltage within the predicted range; Using the control system, the predicted internal resistance of the battery, which is expected to occur within the predicted range, is determined based on the predicted terminal voltage. Using the control system, the real-time internal resistance of the battery is determined based on the measured terminal voltage of the battery and the battery model, wherein the battery model correlates the measured operating parameters with model parameters including the internal resistance. When the measured terminal voltage of the battery is less than the lower voltage threshold, the control system determines the charging power limit based on the predicted internal resistance of the battery expected to occur within the predicted range. When the measured terminal voltage of the battery is greater than the lower voltage threshold, the control system determines the charging power limit based on the real-time internal resistance of the battery. and When the target charging power is greater than the charging power limit, the control system instructs the power source to adjust the charging power supplied to the battery based on the charging power limit.

14. The method of claim 13, comprising: Using the control system, a measured current flowing through the battery is determined based on sensor data received from the second sensor.

15. The method of claim 14, comprising: The control system is used to determine the open-circuit voltage of the battery; and When the measured terminal voltage of the battery is greater than the lower limit of the voltage threshold, the control system uses the difference between the measured terminal voltage of the battery and the open circuit voltage of the battery divided by the measured current flowing through the battery to determine the real-time internal resistance of the battery.

16. The method of claim 15, comprising: Using the control system, the state of charge of the battery is determined based on the measured current flowing through the battery; and Using the control system, the open-circuit voltage of the battery is determined based on the state of charge of the battery.

17. The method of claim 13, further comprising: when the measured terminal voltage of the battery exceeds an upper voltage threshold, wherein the upper voltage threshold is greater than a lower voltage threshold, instructing a switching device electrically coupled between the battery and the power source to switch to an open position using the control system.

18. The method of claim 13, wherein the measured terminal voltage of the battery is determined and the predicted terminal voltage of the battery is determined when the measured terminal voltage of the battery is less than a lower voltage threshold, and wherein the real-time internal resistance of the battery is determined when the measured terminal voltage of the battery is greater than the lower voltage threshold.

19. A battery system, comprising: The battery includes terminals for electrical coupling to an electrical system; One or more sensors, electrically coupled to the battery and configured to determine sensor data indicating measured operating parameters of the battery, including measured terminal voltages; and A battery control system, communicatively coupled to the one or more sensors, is programmed to: Determine the predicted internal resistance of the battery within the predicted range; Determine the real-time internal resistance of the battery within the predicted range; When the measured terminal voltage of the battery is less than the lower voltage threshold, the charging of the battery is controlled using a charging power limit determined based on the predicted internal resistance. and When the measured terminal voltage of the battery is greater than the lower voltage threshold, the charging of the battery is controlled using the charging power limit determined based on the real-time internal resistance.

Images