Computer program, determination device, and determination method

Abstract

To provide a computer programs, a determination device, and a determination method.SOLUTION: A computer program causes a computer to execute processing of estimating the state of at least one of a power storage device and a charging system, and determining the compatibility between the power storage device and the charging system on the basis of the estimated state by executing a simulation using a battery model that simulates the power storage device and a charging system model that simulates the charging system that charges the power storage device.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a computer program, a determination device, and a determination method. [Background technology]

[0002] BACKGROUND ART Vehicles such as EVs (Electric Vehicles) and HEVs (Hybrid Electric Vehicles) are equipped with batteries and charging systems for charging the batteries (see, for example, Patent Document 1).

[0003] Such a charging system acquires various information such as the battery temperature, SOC (State Of Charge), voltage, and current from a BMU (Battery Management Unit), and performs charging control based on the acquired information. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-062018 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the charging control specifications of the charging system equipped in the vehicle do not match the performance of the battery installed in the vehicle, there is a possibility that more power than allowed will be supplied to the battery or the time required for charging will be extremely long. If such a defect is found during the stage of comprehensive verification of the vehicle system with the battery actually installed, it may become necessary to revise the charging control specifications of the charging system or change the type of battery installed in the vehicle, which creates the problem of not being able to reach an agreement on the specifications quickly.

[0006] An object of the present invention is to provide a computer program, a determination method, and a determination device for determining compatibility between a charging system and an electricity storage device through simulation. [Means for solving the problem]

[0007] The computer program causes a computer to execute a simulation using a battery model that simulates a power storage device and a charging system model that simulates a charging system that charges the power storage device, thereby estimating the behavior of charging control for the power storage device, and executing a process to determine compatibility between the power storage device and the charging system based on the estimated behavior of charging control.

[0008] The determination device includes an estimation unit that estimates the behavior of charging control for the power storage device by performing a simulation using a battery model that simulates the power storage device and a charging system model that simulates a charging system that charges the power storage device, and a determination unit that determines compatibility between the power storage device and the charging system based on the estimated behavior of charging control.

[0009] The determination method uses a computer to perform a simulation using a battery model that simulates the storage device and a charging system model that simulates the charging system that charges the storage device, thereby estimating the behavior of charging control for the storage device, and determines the compatibility between the storage device and the charging system based on the estimated behavior of charging control. [Effects of the Invention]

[0010] According to the present application, the compatibility between a charging system and a power storage device can be determined by simulation. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a block diagram illustrating the configuration of a control system in a vehicle. [Figure 2] FIG. 2 is a block diagram showing the internal configuration of the power storage device. [Figure 3] 1 is a block diagram illustrating an internal configuration of a development support device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram showing the configuration of a simulation model used by the development support device. [Figure 5] FIG. 1 is a circuit diagram illustrating an overview of a battery model. [Figure 6] 10 is a graph showing simulation results of charging voltage and battery voltage. [Figure 7] 10 is a graph showing the results of a simulation of a current applied to an electricity storage device. [Figure 8] 10 is a flowchart showing a procedure of a process executed by the development support device. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the embodiment, the computer program causes a computer to estimate the state of at least one of the power storage device and the charging system by performing a simulation using a battery model that simulates a power storage device and a charging system model that simulates a charging system that charges the power storage device, and to perform a process of determining compatibility between the power storage device and the charging system based on the estimated state. When designing an energy storage device, battery characteristics change when the internal structure is changed, or when the composition of the active material or electrolyte is changed. If battery characteristics change, the charge control must be adjusted accordingly. For energy storage devices, overcharging and over-discharging must be avoided, making charge control extremely important. When determining compatibility between an energy storage device and a charging system using a model-based simulation, as in this embodiment, a charging device that generates high voltages during charge control is not required, resulting in high safety. Furthermore, verification using actual devices or prototypes requires charging the actual battery, which takes time to obtain compatibility results. However, when determining compatibility using simulation, battery charging is not required, so compatibility results can be obtained quickly. Considering the recent remarkable developments in electric vehicles, renewable energy, smart grids, and other technologies, expectations are high for high-performance, highly safe energy storage devices, and the significance of using simulation to design safety and shorten development time is significant.

[0013] In the computer program, the state estimated by the simulation may include a time change in a charging system voltage determined according to the state of the power storage device and a time change in a battery voltage, which is a voltage across the power storage device, and the computer may execute a process for determining compatibility between the power storage device and the charging system based on the difference between the charging system voltage and the battery voltage. In verification using an actual device or a prototype, if the voltage difference between the charging system voltage and the battery voltage becomes large, the current flowing into the battery may exceed the allowable limit, making it impossible to ensure safety. In contrast, in this embodiment, compatibility is determined by a simulation using a model, so safety can be ensured even in situations where an excessive current flows.

[0014] In the computer program, the state estimated by the simulation may include a time change in an applied current applied to the power storage device during charging, and the computer may execute a process to determine compatibility between the power storage device and the charging system based on the difference between the applied current and a set tolerance for the applied current. Verification using an actual device or prototype may result in the current flowing into the battery exceeding the tolerance, making it impossible to ensure safety. In contrast, in this embodiment, compatibility is determined by a simulation using a model, ensuring safety even in situations where a current exceeding the tolerance flows.

[0015] In the computer program, the charging system model may be set using a transfer function that represents the relationship between the control input and the control output in the charging system. In verification using an actual device or a prototype, a delay may occur between the control input and the control output in the charging system. For example, if it takes a long time for the voltage to drop to a target value, a current greater than the allowable value will flow in the battery, making safety unsatisfactory. On the other hand, if it takes a long time for the voltage to rise to the target value, charging will take a long time, and there is a possibility that a power shortage will continue for a long time. In contrast, in this embodiment, a transfer function is set in the charging system model, and compatibility between the power storage device and the charging system is determined by simulation. This ensures safety even in situations where a current greater than the allowable value flows, and compatibility determination results can be obtained quickly even in situations where an actual device or a prototype requires a long charging time.

[0016] In the computer program, the charging system model may simulate a control delay in the charging system. In verification using an actual device or a prototype, a delay may occur between the control input and the control output in the charging system. For example, if it takes a long time for the voltage to drop to a target value, a current greater than the allowable value flows in the battery, making it impossible to ensure safety. Furthermore, if it takes a long time for the voltage to rise to the target value, there is a possibility that a power shortage state will continue for a long time. In contrast, in this embodiment, a transfer function is set in the charging system model, and the compatibility between the power storage device and the charging system is determined by simulation, thereby ensuring safety even in situations where a current greater than the allowable value flows. Furthermore, even if the charging time required for an actual device or a prototype is long, a compatibility determination result can be obtained quickly.

[0017] In the computer program, the battery model may include an equivalent circuit of the power storage device. With this configuration, the equivalent circuit of the power storage device is used, so safety can be ensured even in a situation where a current higher than the allowable limit flows in an actual device or a prototype.

[0018] The determination device in the embodiment includes an estimation unit that estimates the state of at least one of the power storage device and the charging system by performing a simulation using a battery model that simulates the power storage device and a charging system model that simulates the charging system that charges the power storage device, and a determination unit that determines compatibility between the power storage device and the charging system based on the estimated state. When designing an energy storage device, battery characteristics change when the internal structure is changed, or when the composition of the active material or electrolyte is changed. If battery characteristics change, charging control must be adjusted accordingly. For energy storage devices, overcharging and over-discharging must be avoided, making charge control extremely important. When determining compatibility between an energy storage device and a charging system through a model-based simulation, as with the determination device of this embodiment, a charging device that generates high voltages during charge control is not required, resulting in high safety. Furthermore, verification using an actual device or prototype requires charging the actual battery, which takes time to obtain compatibility results. However, when determining compatibility through simulation using a determination device, battery charging is not required, and compatibility results can be obtained quickly. Considering the recent remarkable developments in electric vehicles, renewable energy, smart grids, and other technologies, expectations are high for high-performance, highly safe energy storage devices, and the significance of using simulation to design safety and shorten development time is significant.

[0019] In the embodiment, the determination method uses a computer to perform a simulation using a battery model that simulates a power storage device and a charging system model that simulates a charging system that charges the power storage device, thereby estimating the state of at least one of the power storage device and the charging system, and determines the compatibility between the power storage device and the charging system based on the behavior of the estimated state. When designing an energy storage device, battery characteristics change when the internal structure is changed, or when the composition of the active material or electrolyte is changed. If battery characteristics change, charging control must be adjusted accordingly. Energy storage devices must avoid overcharging and over-discharging, making charging control extremely important. When determining compatibility between an energy storage device and a charging system using a model-based simulation, as in the determination method of this embodiment, a charging device that generates high voltages during charging control is not required, resulting in high safety. Furthermore, verification using actual devices or prototypes requires charging the actual battery, which takes time to obtain compatibility results. However, when determining compatibility using computer-based simulation, battery charging is not required, and compatibility results can be obtained quickly. Considering the recent remarkable developments in electric vehicles, renewable energy, smart grids, and other technologies, expectations are high for high-performance, highly safe energy storage devices, and the significance of using simulation to design safety and shorten development time is significant.

[0020] Hereinafter, as an embodiment of the present invention, an example of application to a charging system mounted on a vehicle such as a hybrid electric vehicle (HEV) or an electric vehicle (EV) will be described.

[0021] 1 is a block diagram illustrating the configuration of a control system in a vehicle. The control system of a vehicle C includes a power storage device 10, a charging system 20 for charging the power storage device 10, and a vehicle ECU (Electronic Control Unit) 30 that controls the entire vehicle. The power storage device 10, the charging system 20, and the vehicle ECU 30 are connected to each other so as to be able to communicate with each other via an in-vehicle line such as a CAN (Controller Area Network) or a LIN (Local Interconnect Network). In this embodiment, the vehicle ECU 30 monitors the running state of the vehicle C, the charging state of the power storage device 10, etc., and performs control such as switching between charging and discharging the power storage device 10 depending on the running state of the vehicle C and the charging state of the power storage device 10.

[0022] The power storage device 10 includes a power storage element 11 and a BMU 12 (Battery Management Unit) (see FIG. 2 ). The power storage element 11 is configured, for example, as an assembled battery formed by connecting a plurality of batteries in series. The power storage element 11 included in the power storage device 10 is charged with power supplied from a charging system 20 of the vehicle C, and supplies the power to a load in response to a control command from a vehicle ECU 30. One example of a load to which the power storage device 10 supplies power is an electric motor 23 that generates driving torque for running the vehicle C. Other examples of the load include various accessories included in the vehicle C, such as headlights, turn signal lights, interior lights, and power windows. The BMU 12 has a function of managing the power storage device 10. The BMU 12 has a function of estimating the state of the power storage device 10, a function of detecting an abnormality in the power storage device 10, and the like, and notifies the vehicle ECU 30 of information on the estimated state (e.g., SOC) of the power storage device 10, information on the detected abnormality, and the like.

[0023] The charging system 20 includes a charging ECU 21 and an alternator 22. The alternator 22 is a generator connected to an output shaft of an engine (not shown) and is configured to generate electricity when the output shaft rotates. The electric power obtained by the power generation by the alternator 22 is supplied to the power storage device 10 and a load provided in the vehicle C under control of the charging ECU 21. The alternator 22 performs regenerative control to generate electricity when the vehicle C is decelerating, thereby acting as a load on the rotation of the engine output shaft to apply a braking force to the vehicle C and supplying the generated electric power to the power storage device 10 and a load provided in the vehicle C.

[0024] 2 is a block diagram showing the internal configuration of the power storage device 10. In addition to the power storage element 11 and the BMU 12, the power storage device 10 includes a current sensor 13, a voltage sensor 14, a temperature sensor 15, and a relay 16. The power storage element 11 is composed of, for example, a plurality of lithium ion secondary batteries connected in series.

[0025] Current sensor 13 is provided between power storage element 11 and negative terminal 10A, and measures the current flowing into power storage element 11. Current sensor 13 outputs the measurement result to BMU 12.

[0026] Voltage sensor 14 is connected in parallel to storage element 11 and measures the voltage across storage element 11. Voltage sensor 14 outputs the measurement result to BMU 12.

[0027] The temperature sensor 15 is provided inside or outside the power storage device 10 and measures the temperature. A plurality of temperature sensors 15 may be provided. The temperature measured by the temperature sensor 15 is, for example, the temperature of the power storage element 11. In this case, the temperature sensor 15 is provided near the power storage element 11 (inside the power storage device). The temperature measured by the temperature sensor 15 may be the temperature of the environment in which the power storage device 10 is installed (ambient temperature). In this case, the temperature sensor 15 is provided near the power storage device 10. In the following description, the temperature of the power storage element 11 and the ambient temperature will not be distinguished from each other and will be referred to as the temperature of the power storage device 10. The temperature sensor 15 outputs the measurement result to the BMU 12.

[0028] The relay 16 is provided between the energy storage element 11 and the positive terminal 10B, and is a circuit element for disconnecting or connecting the charge / discharge path of the energy storage element 11 in response to a control command from the BMU 12. When the energy storage device 10 is functioning normally, the charge / discharge path is connected, allowing charging of the energy storage element 11 from the outside and power supply (discharge) from the energy storage element 11 to the load. On the other hand, when any abnormality is detected in the energy storage device 10, the charge / discharge path is disconnected in response to a control command from the BMU 12, and charging of the energy storage element 11 and power supply (discharge) to the load are stopped. In this embodiment, the relay 16 is an example of a circuit element for connecting or disconnecting the charge / discharge path. Alternatively, a semiconductor switch such as a field-effect transistor (FET) may be used to connect or disconnect the charge / discharge path.

[0029] The BMU 12 is a device for managing the state of the power storage device 10 and includes, for example, a control unit 121, a storage unit 122, a connection unit 123, and a communication unit 124. The control unit 121 includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and the like. The CPU included in the control unit 121 executes a control program pre-stored in the ROM to realize functions such as estimating the state of the power storage device 10 and detecting abnormalities in the power storage device 10. The RAM temporarily stores various information generated during execution of calculations by the CPU. The storage unit 122 is configured with an electronically erasable programmable read-only memory (EEPROM) and the like, and stores data necessary for control. The connection unit 123 is connected to the current sensor 13, the voltage sensor 14, the temperature sensor 15, the relay 16, and the like. The communication unit 124 is communicably connected to the vehicle ECU 30 via an in-vehicle line such as a CAN or LIN.

[0030] The control unit 121 of the BMU 12 acquires the current value measured by the current sensor 13, the voltage value measured by the voltage sensor 14, and the temperature measured by the temperature sensor 15 via the connection unit 123, and calculates target values ​​for the SOC and charging voltage of the power storage device 10 based on this data. The control unit 121 notifies the vehicle ECU 30 of the calculated target values ​​for the SOC and charging voltage via the communication unit 124. Furthermore, if, for example, the temperature measured by the temperature sensor 15 exceeds a preset threshold, the control unit 121 determines that an abnormality in the power storage device 10 has been detected, and outputs a control command to the relay 16 to shut off the charge / discharge path.

[0031] In this embodiment, the power storage device 10 is configured to include the BMU 12. Alternatively, the BMU 12 may be provided outside the power storage device 10.

[0032] The charging system 20 to be mounted on the vehicle C is developed and manufactured, for example, by a vehicle manufacturer, and the power storage device 10 is developed and manufactured, for example, by a battery manufacturer. If the charging control specifications of the charging system 20 to be mounted on the vehicle C do not match the performance of the power storage device 10 incorporated in the vehicle C, there is a possibility that more power than allowed will be supplied to the power storage device 10, or that the time required for charging will be extremely long. If a defect such as that described above is found at the time when the power storage device 10 is incorporated in the vehicle C and a comprehensive inspection of the entire vehicle is performed, it may become necessary to review the charging control specifications of the charging system 20 or change the type of power storage device 10 to be incorporated in the vehicle C, and therefore it is not possible to reach an agreement on the specifications quickly.

[0033] In this embodiment, a computer (development support device 100 shown in FIG. 3) independent of vehicle C executes a simulation using a model that simulates the energy storage device 10 and a model that simulates the charging system 20 of vehicle C, and determines the compatibility between the energy storage device 10 mounted on vehicle C and the charging system 20 equipped in vehicle C.

[0034] 3 is a block diagram illustrating the internal configuration of development support device 100 according to this embodiment. Development support device 100 is a general-purpose or dedicated computer, and includes control unit 101, storage unit 102, communication unit 103, operation unit 104, display unit 105, etc.

[0035] The control unit 101 is configured with a CPU, a ROM, a RAM, etc. The CPU included in the control unit 101 loads various computer programs stored in the ROM or the storage unit 102 onto the RAM and executes them, thereby causing the entire device to function as the determination device of the present application.

[0036] The control unit 101 is not limited to the above configuration, and may be any processing circuit or arithmetic circuit including multiple CPUs, a multi-core CPU, a GPU (Graphics Processing Unit), a microcomputer, a volatile or non-volatile memory, etc. The control unit 101 may also have functions such as a timer that measures the elapsed time from when an instruction to start measurement is given until when an instruction to end measurement is given, a counter that counts numbers, and a clock that outputs date and time information.

[0037] The storage unit 102 includes a storage device using a hard disk drive (HDD), a solid state drive (SSD), or the like. The storage unit 102 stores various computer programs executed by the control unit 101, data required for executing the computer programs, and the like. The computer programs stored in the storage unit 102 include a determination program PG that uses a battery model BM that simulates the power storage device 10 and a charging system model CSM that simulates the charging system 20 on the vehicle side to estimate the behavior of charging control for the power storage device 10 and determine compatibility between the power storage device 10 and the charging system 20. The determination program PG may be a single computer program or a group of programs configured from a plurality of programs.

[0038] The computer program stored in the storage unit 102 is provided, for example, by a non-transitory storage medium M on which the computer program is readably recorded. The storage medium M is a portable memory such as a CD-ROM, a Universal Serial Bus (USB) memory, a Secure Digital (SD) card, a micro SD card, or a CompactFlash (registered trademark). In this case, the control unit 101 reads the computer program from the storage medium M using a reading device (not shown) and installs the read computer program in the storage unit 102. Alternatively, the computer program stored in the storage unit 102 may be provided by communication via the communication unit 103. In this case, the control unit 101 may obtain the computer program through the communication unit 103 and install the obtained computer program in the storage unit 102.

[0039] The storage unit 102 stores various data in addition to computer programs. For example, the storage unit 102 stores a battery model BM that simulates the power storage device 10 and a charging system model CSM that simulates the charging system 20. The battery model BM includes, for example, an equivalent circuit that represents the power storage element 11. The storage unit 102 stores information about the circuit configuration of the equivalent circuit and values ​​of each element that configures the equivalent circuit. The battery model BM may further include a BMU model that simulates the operation of the BMU 12. The charging system model CSM is set using a transfer function that represents the relationship between the control input and the control output in the charging system 20. The storage unit 102 stores parameters that describe the transfer function between the control input and the control output, etc.

[0040] The storage unit 102 may have a battery table BT that stores information about the power storage device 10 in association with an identifier that identifies the power storage device 10. The battery information registered in the battery table BT includes, for example, information about the positive and negative electrodes, information about the electrolyte, and information about the tabs. The information about the positive and negative electrodes includes information such as the names of the active materials of the positive and negative electrodes, thickness, width, depth, and open circuit potential. The information about the electrolyte and the tabs includes information about the ion species, transport number, diffusion coefficient, and conductivity. The information registered in the battery table BT may also include information about the components that make up the power storage device 10. The information stored in the battery table BT is used as part of the parameters when the above-mentioned simulation is performed.

[0041] The communication unit 103 includes a communication interface for communicating with an external device via a communication network (not shown). The external device is, for example, an information processing terminal such as a computer or smartphone used by a user. When information to be transmitted to the external device is input from the control unit 101, the communication unit 103 transmits the input information to the external device and also outputs information received from the external device via the communication network to the control unit 101.

[0042] The communication unit 103 may be configured to be able to communicate with the vehicle ECU 30 and the BMU 12 included in the power storage device 10. The control unit 101 may acquire information related to the running state of the vehicle C, various measurement values ​​measured by the power storage device 10, and the like through the communication unit 103, and may perform a simulation based on the acquired information.

[0043] The operation unit 104 is equipped with an input interface such as a keyboard, a mouse, and a touch panel, and accepts operations by the user. The display unit 105 is equipped with a liquid crystal display device or the like, and displays information to be notified to the user. Note that, in this embodiment, the development support device 100 is configured to include the operation unit 104 and the display unit 105, but the operation unit 104 and the display unit 105 are not essential, and the development support device 100 may be configured to accept operations via a computer connected externally to the development support device 100, and output information to be notified to the external computer.

[0044] The configuration of the simulation model will be described below. 4 is a block diagram showing the configuration of a simulation model used by the development support device 100. The development support device 100 estimates the behavior of charge control in the vehicle C by executing a simulation using a charging system model CSM that simulates the charging system 20 and a battery model BM that simulates the power storage device 10.

[0045] The charging system model CSM receives as input a power pattern that is assumed when the vehicle C is in use and a target value of the charging voltage that is set based on the estimation result of the battery model BM. Here, the power pattern that is assumed when the vehicle C is in use represents the change in power over time when the vehicle C repeatedly starts, runs, and stops, and is calculated from the difference between the power generated by the alternator 22 and the power consumption of the vehicle. The charging system model CSM uses this power pattern as a control input x(t) and calculates a control output y(t) based on the target value of the charging voltage. The control output y(t) represents, for example, the charging voltage that the alternator 22 supplies to the power storage device 10.

[0046] In this embodiment, a transfer function G(s) is set between the control input x(t) and the control output y(t) in consideration of the occurrence of a control delay in the charging system 20. The form of the transfer function G(s) can be determined based on actual measurements of the power pattern during use of the vehicle C, the time change in the power generated by the alternator 22, the time change in the power consumed by the vehicle C, and the like. It is preferable that the transfer function G(s) has a form that simulates the slew rate of the control response in the charging system 20.

[0047] When a transfer function G(s) is given, the control unit 101 of the development support device 100 calculates the control output y(t) for the control input x(t) of the charging system model CSM in the following procedure. First, the control unit 101 performs a Laplace transform on the control input x(t) to obtain a function X(s). Next, the control unit 101 multiplies the function X(s) by the transfer function G(s) to obtain an output Y(s) = G(s)X(s). The control unit 101 performs an inverse Laplace transform on the output Y(s) to obtain the control output y(t).

[0048] The battery model BM estimates the voltage (open circuit voltage Vo) and SOC of the storage element 11 when a charging voltage (i.e., the control output y(t) of the charging system model CSM) is given. Furthermore, the battery model BM determines a target value for the charging voltage based on the estimated SOC and feeds it back to the charging system model CSM.

[0049] 5 is a circuit diagram illustrating an outline of the battery model BM. The battery model BM includes an equivalent circuit of a storage element 11. The equivalent circuit of the storage element 11 is described by, for example, a resistance element R0, a first RC parallel circuit formed by connecting a resistance element R1 and a capacitance element C1 in parallel, a second RC parallel circuit formed by connecting a resistance element R2 and a capacitance element C2 in parallel, and a constant voltage source V0.

[0050] Resistance element R0 represents the DC resistance component (DC impedance) of storage element 11. The DC resistance component of storage element 11 corresponds to, for example, the resistance of the electrodes in storage element 11. The resistance value of resistance element R0 is a value that changes depending on the discharge current, charge voltage, SOC, temperature, etc. Once the resistance value of resistance element R0 is determined, it is possible to calculate the voltage generated across resistance element R0 when current I(t) flows through this equivalent circuit. The voltage generated across resistance element R0 is defined as the DC resistance voltage Vdc(t).

[0051] The two RC parallel circuits are circuit elements for describing the transient polarization characteristics of the power storage device 10. The values ​​of the resistive element R1 and the capacitive element C1 that constitute the first RC parallel circuit and the resistive element R2 and the capacitive element C2 that constitute the second RC parallel circuit are given as values ​​that vary depending on the SOC of the power storage device 10. Once these values ​​are determined, the impedances of the first RC parallel circuit and the second RC parallel circuit are determined. Once the impedances are determined, it is possible to calculate the voltage (polarization voltage Vp(t)) generated in the first RC parallel circuit and the second RC parallel circuit when a current I(t) flows through this equivalent circuit. The polarization voltage Vp(t) is the sum of the polarization voltage Vp1(t) generated in the first RC parallel circuit and the polarization voltage Vp2(t) generated in the second RC parallel circuit.

[0052] Here, the time constant of the first RC parallel circuit is τ1, and the time constant of the second RC parallel circuit is τ2. The time constant τ1 is determined by multiplying the resistance of the resistive element R1 and the capacitance of the capacitive element C1 in the first RC parallel circuit. The time constant τ1 is reflected in the time change of the polarization voltage Vp1(t) generated in the first RC parallel circuit. Similarly, the time constant τ2 is determined by multiplying the resistance of the resistive element R2 and the capacitance of the capacitive element C2 in the second RC parallel circuit. The time constant τ2 is reflected in the time change of the polarization voltage Vp2(t) generated in the second RC parallel circuit. By varying the time constants τ1 and τ2, various phenomena occurring within the energy storage element 11 can be represented.

[0053] The constant voltage source V0 is a voltage source that outputs a DC voltage. The voltage output by the constant voltage source V0 represents the open circuit voltage (OCV) of the storage element 11 and is denoted as Vo(t). The open circuit voltage Vo(t) is given as a function of the SOC, temperature, etc.

[0054] The terminal voltage V(t) between the positive terminal PT and the negative terminal NT is calculated using the DC resistance voltage Vdc(t), the polarization voltage Vp(t), and the open circuit voltage Vo(t): V(t)=Vdc(t)+Vp(t)+Vo(t) is given as:

[0055] The values ​​of each element constituting the equivalent circuit are determined based on, for example, actual measurement results, taking into consideration the relationship between current, SOC, and the like.

[0056] Below, the results of a simulation using the charging system model CSM and the battery model BM are shown.

[0057] Figure 6 is a graph showing simulation results of charging voltage and battery voltage. Figure 6A shows the simulation results when the slew rate of the control response in charging system 20 is small, and Figure 6B shows the simulation results when the slew rate of the control response in charging system 20 is large. The horizontal axis of each graph represents time (sec), and the vertical axis represents voltage (V).

[0058] The simulation results in Fig. 6 show the time change of the charging system voltage and the time change of the battery voltage when the power storage device 10 is charged to a target voltage. Here, the charging system voltage represents a voltage determined based on a control input (power pattern) in the charging system 20. The battery voltage represents the terminal voltage of the power storage device 10 (terminal voltage V(t) shown in Fig. 5).

[0059] As can be seen from the voltage difference graph in Figure 6A, when the slew rate of the control response is small, the difference between the charging system voltage and the battery voltage is relatively small. On the other hand, as can be seen from the voltage difference graph in Figure 6B, when the slew rate of the control response is large, the difference between the charging system voltage and the battery voltage is relatively large.

[0060] Fig. 7 is a graph showing the simulation results of the current applied to the power storage device 10. Fig. 7A shows the simulation results when the slew rate of the control response in the charging system 20 is small, and Fig. 7B shows the simulation results when the slew rate of the control response in the charging system 20 is large. The horizontal axis of each graph represents time (sec), and the vertical axis represents current (mA).

[0061] The simulation results in Fig. 7 show the change over time in the current input to the power storage device 10 when the power storage device 10 is charged to a target voltage. The simulation results in Fig. 6 and Fig. 7 show that when the voltage difference between the charging system 20 and the power storage device 10 increases, the amount of current input to the power storage device 10 may exceed the allowable limit.

[0062] The control unit 101 of the development support device 100 determines the compatibility between the power storage device 10 and the charging system 20 based on these simulation results. For example, the control unit 101 may set a determination threshold for the voltage difference between the charging system voltage and the battery voltage obtained as a simulation result, and determine the compatibility between the power storage device 10 and the charging system 20 based on the magnitude relationship between the calculated voltage difference and the determination threshold. In this case, the control unit 101 determines that the compatibility is not good when the calculated voltage difference is equal to or greater than the determination threshold, and determines that the compatibility is good when the calculated voltage difference is less than the determination threshold.

[0063] Furthermore, the control unit 101 may compare the magnitude of the applied current obtained as a result of the simulation with the allowable current, and based on the comparison result, determine the compatibility between the power storage device 10 and the charging system 20. In this case, the control unit 101 determines that the compatibility is not good if the calculated applied current is equal to or greater than the allowable current, and determines that the compatibility is good if the calculated applied current is less than the allowable current.

[0064] 8 is a flowchart showing the procedure of processing executed by the development support device 100. The control unit 101 of the development support device 100 sets a charging system model CSM that simulates the charging system 20 provided in the vehicle C and a battery model BM that simulates the power storage device 10 mounted on the vehicle C (step S101). At this time, the control unit 101 may set a transfer function G(s) used in the charging system model CSM and values ​​of each element that configures the equivalent circuit of the power storage element 11. Alternatively, the transfer function G(s) and values ​​of each element may be set in advance. In this case, the control unit 101 may read out the transfer function G(s) and values ​​of each element from the storage unit 102.

[0065] Next, the control unit 101 acquires a power pattern that is assumed when vehicle C is in use and a target value for the charging voltage (step S102). The power pattern that is assumed when vehicle C is in use represents the change in power over time when vehicle C repeatedly starts, runs, and stops. The power pattern is set in advance assuming the time when vehicle C will be in use. The target value for the charging voltage is a value that is set based on information such as SOC. In step S102, the target value (initial value) for the charging voltage can be set according to the power pattern to be used.

[0066] Next, the control unit 101 executes a simulation using the charging system model CSM and the battery model BM (step S103). By using the charging system model CSM, the control unit 101 calculates a charging voltage (control output y(t)) that represents the control response of the charging system 20 to a control input x(t) according to the power pattern. Furthermore, by using the battery model BM, the control unit 101 estimates the voltage (open circuit voltage Vo) and SOC of the storage element 11 when a charging voltage is applied. Based on the estimated SOC, the control unit 101 determines a target value for the charging voltage and feeds it back to the charging system model CSM, thereby sequentially estimating the charging voltage and battery voltage at each time.

[0067] Next, the control unit 101 determines whether the voltage difference between the charging system voltage and the battery voltage is equal to or greater than a determination threshold (step S104). If it is determined that the voltage difference is equal to or greater than the determination threshold (S104: YES), the control unit 101 determines that the compatibility between the power storage device 10 and the charging system 20 is good (step S105). On the other hand, if it is determined that the voltage difference is less than the determination threshold (S104: NO), the control unit 101 determines that the compatibility between the power storage device 10 and the charging system 20 is not good (step S106).

[0068] 8 is configured to determine the compatibility between the power storage device 10 and the charging system 20 based on the voltage difference between the charging system voltage and the battery voltage. Alternatively, the current applied to the power storage device 10 obtained as a result of the simulation is compared with the allowable current, and the compatibility between the power storage device 10 and the charging system 20 is determined based on the comparison result. Furthermore, the control unit 101 may be configured to estimate the time required from the start of charging to the end of charging (charging time), and determine the compatibility between the power storage device 10 and the charging system 20 depending on whether the charging time is longer or shorter than a threshold time.

[0069] As described above, in the present embodiment, a simulation is performed using the battery model BM that simulates the power storage device 10 and the charging system model CSM that simulates the charging system 20 to estimate the behavior of the charging control, and the compatibility between the power storage device 10 and the charging system 20 is determined based on the estimation result. Therefore, it is not necessary to perform verification using actual or prototype products of the power storage device 10 and the charging system 20, and the compatibility between the power storage device 10 and the charging system 20 can be determined by the simulation. As a result, the development support device 100 can determine the charge control specifications of the charging system 20 and the power storage device 10 to be mounted on the vehicle C at an early stage of product development.

[0070] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0071] For example, in the present embodiment, the power storage device 10 has been described as a power source for a vehicle. The vehicle is not limited to a four-wheeled vehicle, but may be a two-wheeled vehicle. Alternatively, the vehicle may be a train, an automatic guided vehicle (AGV), an unmanned aerial vehicle (drone), an airplane, or other moving object. The power storage device 10 may be a high-voltage power supply (several hundred volts) for driving the vehicle, an auxiliary battery (12 V or 24 V) for supplying power other than driving, an engine starting battery (12 V or 24 V), or a mild hybrid battery (48 V). Examples of vehicle charging systems include, but are not limited to, regenerative power recovered when the vehicle decelerates, a solar power generator mounted on the roof, a 100 V or 200 V quick charger for charging while parked, and a power storage system incorporating reused batteries. The power storage device 10 may be a power source for an electronic device or a power storage power source. In these cases, the development support apparatus 100 may determine the compatibility of the power storage device with the charging system provided in the electronic device or power storage facility.

[0072] In the present embodiment, the configuration of the energy storage element 11 including a plurality of lithium ion secondary batteries has been described. Alternatively, the energy storage device 10 may be a module in which a plurality of cells are connected, a bank in which a plurality of modules are connected, a domain in which a plurality of banks are connected, or the like. Furthermore, instead of the lithium ion secondary battery, any battery such as an all-solid-state lithium ion battery, a zinc-air battery, a sodium ion battery, or a lead battery may be used. [Explanation of symbols]

[0073] 10. Energy storage devices 20 Charging System 21 Charging ECU 22 Alternator 23 Electric motor 30 Vehicle ECU 100 Development support equipment 101 Control section 102 Storage section 103 Communications Department 104 Operation section 105 Display section BM Battery Model CSM charging system model

Claims

1. On the computer, estimating a state of at least one of the power storage device and the charging system by performing a simulation using a battery model that simulates the power storage device and a charging system model that simulates a charging system that charges the power storage device; Determining compatibility between the power storage device and the charging system based on the estimated state A computer program for executing a process, A computer program in which the state estimated by the simulation includes a change over time in battery voltage, which is the voltage across the power storage device.

2. The battery model simulates a power storage device including a power storage element, a BMU (Battery Management Unit), a current sensor, a voltage sensor, and a circuit element for disconnecting or connecting a charge / discharge path.

2. The computer program of claim 1.

3. The battery model simulates a 12V battery.

3. A computer program according to claim 2.

4. The battery model includes an equivalent circuit that simulates the storage element and a BMU model that simulates the operation of the BMU.

4. A computer program according to claim 2 or claim 3.

5. an estimation unit that estimates a state of at least one of the power storage device and the charging system by executing a simulation using a battery model that simulates the power storage device and a charging system model that simulates a charging system that charges the power storage device; a determination unit that determines compatibility between the power storage device and the charging system based on the estimated state; A determination device comprising: The state estimated by the simulation includes a change over time in the battery voltage, which is the voltage across the power storage device.

6. The computer estimating a state of at least one of the power storage device and the charging system by performing a simulation using a battery model that simulates the power storage device and a charging system model that simulates a charging system that charges the power storage device; Determining compatibility between the power storage device and the charging system based on the estimated state behavior. A determination method comprising: The state estimated by the simulation includes a change over time in a battery voltage, which is a voltage across the power storage device.

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