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] 2. Description of the Related 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] JP 2011-062018 A 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 permitted will be supplied to the battery or the time required for charging will be extremely long. If such a defect is found at the stage of actually installing the battery and performing comprehensive verification of the vehicle system, it may become necessary to review the charging control specifications of the charging system or to change the type of battery installed in the vehicle, which creates the problem that it is not possible to reach an agreement on the specifications early.

[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 by 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 of determining 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 the charging control.

[0009] The determination method involves using 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 behavior of charging control for the power storage device, and determining compatibility between the power storage device and the charging system based on the estimated behavior of charging control. Effect 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 description of the drawings]

[0011] [Figure 1] FIG. 2 is a block diagram illustrating a configuration of a control system in a vehicle. [Diagram 2] FIG. 2 is a block diagram showing an internal configuration of the power storage device. [Diagram 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] 2 is a block diagram showing a configuration of a simulation model used by the development support device; [Diagram 5] FIG. 2 is a circuit diagram for explaining an overview of a battery model. [Figure 6] 11 is a graph showing simulation results of charging voltage and battery voltage. [Figure 7] 13 is a graph showing a simulation result of a current applied to an electricity storage device. [Figure 8] 1 is a flowchart showing a procedure of a process executed by the development support device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The computer program in the embodiment causes a computer to estimate 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 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 the internal structure is changed when designing an energy storage device, or when the composition of the active material or electrolyte is changed, the characteristics of the battery change. When the characteristics of the battery change, it is necessary to change the charging control according to the change in the characteristics. In an energy storage device, overcharging and overdischarging must be avoided, and the importance of charging control is high. When the compatibility between the energy storage device and the charging system is determined by a simulation using a model as in this embodiment, a charging device that generates a high voltage in the charging control is not required, and safety is high. In addition, in verification using an actual device or a prototype, it is necessary to charge the actual battery, so it takes time to obtain the compatibility judgment result, but when it is judged by simulation, it is not necessary to charge the battery, so the compatibility judgment result can be obtained quickly. Considering the recent remarkable development progress of electric vehicles, renewable energy, smart grids, etc., there are high expectations for high-performance and high-safety energy storage devices, and the significance of safety design and shortening development time using simulation is great.

[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 a 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, and safety cannot be guaranteed. In contrast, in this embodiment, compatibility is determined by a simulation using a model, so safety can be guaranteed even in a situation where a current exceeding the allowable limit 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 for determining compatibility between the power storage device and the charging system based on a difference between the applied current and an allowable value set for the applied current. In verification using an actual device or a prototype, the current entering the battery may exceed the allowable value, and safety cannot be guaranteed. In contrast, in this embodiment, compatibility is determined by a simulation using a model, so safety can be guaranteed even in a situation where a current exceeding the allowable value 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 the target value, a current greater than the allowable value flows in the battery, and safety cannot be guaranteed. On the other hand, if it takes a long time for the voltage to rise to the target value, charging takes a long time, and there is a possibility that a state of insufficient power 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, so that safety can be guaranteed even under a situation in which a current greater than the allowable value flows, and a compatibility determination result can be obtained quickly even under a situation in which the charging time continues for a long time in an actual device or a prototype.

[0016] In the computer program, the charging system model may simulate a control delay in the charging system. In a verification using an actual device or a prototype, a delay may occur between a control input and a 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, and safety cannot be guaranteed. Also, if it takes a long time for the voltage to rise to the target value, there is a possibility that a state of insufficient power 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, so that safety can be guaranteed even under a situation where a current greater than the allowable value flows. Also, even if the time required for charging is long in an actual device or a prototype, 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. According to this configuration, since the equivalent circuit of the power storage device is used, safety can be ensured even under a situation where a current higher than a tolerable limit flows in an actual device or a prototype.

[0018] The determination device in the embodiment includes an estimation unit that estimates 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 a 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 state. When the internal structure is changed when designing an energy storage device, or when the composition of the active material or electrolyte is changed, the characteristics of the battery change. When the characteristics of the battery change, it is necessary to change the charging control according to the change in characteristics. In an energy storage device, overcharging and overdischarging must be avoided, and the importance of charging control is high. When the compatibility between an energy storage device and a charging system is determined by a simulation using a model, as in the determination device of this embodiment, a charging device that generates a high voltage in the charging control is not required, and safety is high. In addition, in verification using an actual device or a prototype, it is necessary to charge the actual battery, so it takes time to obtain the compatibility determination result, but when the determination is made by simulation using a determination device, it is not necessary to charge the battery, so the compatibility determination result can be obtained quickly. Considering the recent remarkable development progress of electric vehicles, renewable energy, smart grids, etc., there are high expectations for high-performance and high-safety energy storage devices, and the significance of safety design and shortening development time using simulation is great.

[0019] The determination method in one embodiment 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 the internal structure is changed when designing an energy storage device, or when the composition of the active material or electrolyte is changed, the characteristics of the battery change. When the characteristics of the battery change, it is necessary to change the charging control according to the change in characteristics. In an energy storage device, overcharging and overdischarging must be avoided, and the importance of charging control is high. When the compatibility between an energy storage device and a charging system is determined by a simulation using a model, as in the determination method of this embodiment, a charging device that generates a high voltage in the charging control is not required, and safety is high. In addition, in verification using an actual machine or a prototype, it is necessary to charge the actual battery, so it takes time to obtain the compatibility determination result, but when it is determined by simulation using a computer, it is not necessary to charge the battery, so the compatibility determination result can be obtained quickly. Considering the recent remarkable development progress of electric vehicles, renewable energy, smart grids, etc., there are high expectations for high-performance and high-safety energy storage devices, and the significance of safety design and shortening development time using simulation is great.

[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 vehicle C includes, as the control system configuration, a power storage device 10, a charging system 20 for charging the power storage device 10, and a vehicle ECU (Electronic Control Unit) 30 for executing control of 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 controller area network (CAN) or a local interconnect network (LIN). In this embodiment, the vehicle ECU 30 monitors the running state of the vehicle C, the charging state of the power storage device 10, and the like, and executes control for switching between charging and discharging the power storage device 10 according to 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, for example, an assembled battery including a plurality of batteries connected 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. An example of a load to which the power storage device 10 supplies power is an electric motor 23 that generates a driving torque for running the vehicle C. Other examples of the load include various accessories included in the vehicle C, such as headlights, turn signals, 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 configured to generate electricity by the rotation of the output shaft. Electric power obtained by the power generation of the alternator 22 is supplied to the loads included in the power storage device 10 and 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 becoming a load against the rotation of the engine output shaft and applying a braking force to the vehicle C, and also supplies the generated electric power to the loads included in the power storage device 10 and the vehicle C.

[0024] 2 is a block diagram showing the internal configuration of the power storage device 10. In addition to a power storage element 11 and a 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 energy storage element 11 and negative terminal 10A, and measures the current flowing into energy storage element 11. Current sensor 13 outputs the measurement result to BMU 12.

[0026] The voltage sensor 14 is connected in parallel to the storage element 11, and measures the voltage across the storage element 11. The voltage sensor 14 outputs the measurement result to the 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] Relay 16 is provided between the energy storage element 11 and positive terminal 10B, and is a circuit element for disconnecting or connecting a charge / discharge path of the energy storage element 11 in response to a control command from BMU 12. When the energy storage device 10 is functioning normally, the charge / discharge path is connected, and charging of the energy storage element 11 from the outside and supply of power (discharging) from the energy storage element 11 to a load are possible. 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 BMU 12, and charging of the energy storage element 11 and supply of power (discharging) to the load are stopped. In the present embodiment, the relay 16 is an example of a circuit element for connecting or disconnecting a 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 stored in advance in the ROM to realize 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. The RAM temporarily stores various information generated during the execution of calculations by the CPU. The storage unit 122 is composed of an electronically erasable programmable read only memory (EEPROM) and the like, and stores data necessary for control and the like. 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 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 through the connection unit 123, and calculates the target values ​​of the SOC and charging voltage of the power storage device 10 based on these data. The control unit 121 notifies the vehicle ECU 30 of the calculated SOC and target values ​​of the charging voltage through the communication unit 124. Furthermore, when the temperature measured by the temperature sensor 15 exceeds a preset threshold, for example, 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 cut 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 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 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 permitted will be supplied to the power storage device 10, or the time required for charging will be extremely long. If the above-mentioned defects are found at the time when the power storage device 10 is incorporated in the vehicle C and the entire vehicle is comprehensively verified, it becomes necessary to review the charging control specifications of the charging system 20 or to change the type of the power storage device 10 incorporated in the vehicle C, and therefore it is not possible to reach an agreement on the specifications early.

[0033] In this embodiment, a simulation is performed using a model simulating the power storage device 10 and a model simulating the charging system 20 of the vehicle C in a computer independent of the vehicle C (the development support device 100 shown in FIG. 3), and compatibility between the power storage device 10 mounted on the vehicle C and the charging system 20 equipped in the vehicle C is determined.

[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 composed of 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 equipped with 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 a measurement start instruction is given to when a measurement end instruction 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), etc. The storage unit 102 stores various computer programs executed by the control unit 101, data required for executing the computer programs, etc. The computer programs stored in the storage unit 102 include a determination program PG that estimates the behavior of charging control for the power storage device 10 by using 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, and determines compatibility between the power storage device 10 and the charging system 20. The determination program PG may be a single computer program, or may be 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 recording medium M on which the computer program is readably recorded. The recording 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 Compact Flash (registered trademark). In this case, the control unit 101 reads the computer program from the recording 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 on 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 a control input and a 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, and the like.

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

[0041] The communication unit 103 includes a communication interface for communicating with an external device through a communication network (not shown). The external device is, for example, an information processing terminal such as a computer or a 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 through 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 on 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 perform a simulation based on the acquired information.

[0043] The operation unit 104 has an input interface such as a keyboard, a mouse, a touch panel, etc., and accepts operations by the user. The display unit 105 has a liquid crystal display device, etc., and displays information to be notified to the user. Note that, in this embodiment, the development support device 100 is configured to have 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 now be described. 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 charging 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 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 assumed when the vehicle C is in use represents a 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 consumed by 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 supplied by the alternator 22 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 function form that simulates the slew rate of the control response in the charging system 20.

[0047] When the 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 obtains an output Y(s)=G(s)X(s) by multiplying the function X(s) by the transfer function G(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., a control output y(t) of the charging system model CSM) is given. The battery model BM also 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 for explaining an outline of the battery model BM. The battery model BM includes an equivalent circuit of the 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 the storage element 11. The DC resistance component of the storage element 11 corresponds to, for example, the resistance of the electrodes in the 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 constituting the first RC parallel circuit, and the resistive element R2 and the capacitive element C2 constituting the second RC parallel circuit are given as values ​​that vary according to the SOC of the power storage device 10. Once these values ​​are determined, the impedances in 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 in the first RC parallel circuit is τ1, and the time constant in the second RC parallel circuit is τ2. The time constant τ1 is determined as a value obtained by multiplying the resistance value of the resistive element R1 and the capacitance value of the capacitive element C1 that constitute 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 as a value obtained by multiplying the resistance value of the resistive element R2 and the capacitance value of the capacitive element C2 that constitute 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 making the time constants τ1 and τ2 different, various phenomena that occur in the storage element 11 can be expressed.

[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, and the like.

[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) as follows: V(t)=Vdc(t)+Vp(t)+Vo(t) is given as:

[0055] The values ​​of the elements constituting the equivalent circuit are determined based on, for example, actual measurement results, taking into account relationships such as current and SOC.

[0056] The following shows the results of a simulation using the charging system model CSM and the battery model BM.

[0057] Fig. 6 is a graph showing the simulation results of the charging voltage and the battery voltage. Fig. 6A shows the simulation results when the slew rate of the control response in the charging system 20 is small, and Fig. 6B 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 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 shown 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 shown 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 results of a simulation of a current applied to the power storage device 10. Fig. 7A shows the results of a simulation in which the slew rate of the control response in the charging system 20 is small, and Fig. 7B shows the results of a simulation in which 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 result in Fig. 7 shows the change over time of the current input to the power storage device 10 when the power storage device 10 is charged to a target voltage. It can be seen from the simulation results in Fig. 6 and Fig. 7 that when the voltage difference between the charging system 20 and the power storage device 10 becomes large, 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, when the calculated applied current is equal to or greater than the allowable current, the control unit 101 determines that the compatibility is not good, and when the calculated applied current is less than the allowable current, determines that the compatibility is good.

[0064] 8 is a flowchart showing the procedure of the process 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 equipped 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 assuming use of the vehicle C and a target value of the charging voltage (step S102). The power pattern assuming use of the vehicle C represents the change in power over time when the vehicle C repeatedly starts, runs, and stops. The power pattern is set in advance assuming use of the vehicle C. The target value of the charging voltage is a value that is set based on information such as SOC. In step S102, the target value (initial value) of 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 indicates a control response of the charging system 20 to a control input x(t) according to a power pattern. Furthermore, by using the battery model BM, the control unit 101 estimates the voltage (open 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 of the charging voltage, feeds it back to the charging system model CSM, and sequentially estimates the charging voltage and battery voltage at each time.

[0067] Next, the control unit 101 determines whether or not the voltage difference between the charging system voltage and the battery voltage is equal to or greater than the 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, a configuration is adopted in which the compatibility between the power storage device 10 and the charging system 20 is determined based on the voltage difference between the charging system voltage and the battery voltage. Alternatively, a configuration may be adopted in which the magnitude of the applied current 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, a configuration may be adopted in which the control unit 101 estimates the time required from the start of charging to the end of charging (charging time), and determines the compatibility between the power storage device 10 and the charging system 20 depending on whether the charging time is longer or shorter than the 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, there is no need 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 charging 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 are illustrative in all respects and should not be considered as limiting. 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, and may be a two-wheeled vehicle. Alternatively, the vehicle may be a train, an AGV (Automatic Guided Vehicle), an unmanned aerial vehicle (drone), an aircraft, or other moving object. The power storage device 10 may be a high-voltage power source (several hundred V) 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 a charging system for a vehicle include, but are not limited to, regenerative power recovered when the vehicle decelerates, a solar power generation system mounted on the roof or the like, a 100 V power source or 200 V quick charger for charging while parked, and a power storage system incorporating a reused battery. The power storage device 10 may be a power source for an electronic device, or may be a power source for power storage. In these cases, the development support device 100 may determine the compatibility of the charging system provided in the electronic device or power storage facility with the power storage device.

[0072] In the present embodiment, the configuration of the energy storage element 11 composed of 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. In addition, 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 adopted instead of the lithium ion secondary battery. [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 executing 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; Based on the estimated state, a compatibility between the power storage device and the charging system is determined. A computer program for executing a process, A computer program, wherein the state estimated by the simulation includes a change over time in a 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 battery management unit (BMU), a current sensor, a voltage sensor, and a circuit element for disconnecting or connecting a charge / discharge path.

2. The computer program product 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. A computer program according to claim 2 or 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 a 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 a battery voltage, which is a voltage across both ends of the power storage device.

6. The computer estimating 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 a 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 method of determining A determination method in which the state estimated by the simulation includes a change over time in a battery voltage, which is a voltage across both ends of the power storage device.

Images