Battery control device and battery control method

Abstract

According to the present invention, a controller acquires a discharge state of a battery while the battery is discharging, sets a predetermined time on the basis of the discharge state, and restricts the charging of the battery until the predetermined time elapses after the discharge of the battery is completed.

Description

Battery control device and battery control method 【0001】 The present invention relates to a battery control device and a battery control method. 【0002】 There is known a technique of performing pre-conditioning by an air conditioner using power from a high-voltage battery, and then waiting for the polarization relaxation time of the high-voltage battery to elapse in a state where charging using power from an external power source is not performed, and then recharging the high-voltage battery (Patent Document 1). 【0003】 Japanese Unexamined Patent Application Publication No. 2009-303291 【0004】 However, since the time required for the polarization of the battery to disappear after discharge varies depending on the discharge state of the battery, in the technique described in Patent Document 1 in which the polarization relaxation time is set based on the battery temperature, there is a problem that the battery cannot be charged appropriately. 【0005】 The problem to be solved by the present invention is to provide a battery control device and a battery control method capable of more appropriately charging the battery after discharge. 【0006】 The present invention solves the above problem by obtaining the discharge state of the battery while the battery is discharging, setting a predetermined time based on the discharge state, and restricting the charging of the battery until the predetermined time elapses after the discharge of the battery ends. 【0007】 According to the present invention, the battery can be more appropriately charged after discharge. 【0008】Figure 1 is a block diagram of a battery control system according to one embodiment of the present invention. Figure 2 is a block diagram showing an example of a battery controller according to this embodiment. Figure 3 is a diagram illustrating the correspondence between the battery's SOH, discharge current value, discharge amount, and temperature, and the depolarization time. Figure 4 is a diagram illustrating the correspondence between the combination of the battery's SOC and depolarization time, and the charging power at the limiting time. Figure 5 is a flowchart of the control flow of the calculation method for the amount of SOC decrease from a fully charged battery according to this embodiment. Figure 6 is a flowchart of the control flow of the method for setting a full charge flag due to SOC decrease of the battery according to this embodiment. Figure 7 is a diagram showing an example of battery charging limiting according to this embodiment. Figure 8 is a flowchart of the control flow of the charging control method for depolarizing battery 3 according to this embodiment. Figure 9 is a flowchart of the control flow of the battery control method by the battery controller according to this embodiment. 【0009】 Hereinafter, an embodiment of the battery control device and battery control method according to the present invention will be described with reference to the drawings. Figure 1 is a block diagram of a battery control system according to an embodiment of the present invention. The battery control system comprises a battery 3 including a plurality of cells (batteries) 1, an inverter 2, a relay switch 4, a motor 5, a total voltage sensor 6, a current sensor 7, a temperature sensor 8, a battery controller 100, and a vehicle controller 200. The battery controller 100 is an example of the "controller" of the present invention. At least the device including the battery controller 100 corresponds to the "battery control device" of the present invention, and the control processing performed by the battery controller 100 corresponds to the "battery control method" of the present invention. 【0010】Battery 3 has battery modules M1, M2, and M3, each consisting of n cells (batteries) 1 connected in series (n is an arbitrary positive integer; in the example shown in Figure 1, n = 4). For example, lithium-ion batteries are used for cell 1. Battery 3 is a rechargeable secondary battery that can be charged by an external charger. By connecting a charging cable to the vehicle, battery 3 is electrically connected to the external charger in a rechargeable state. Battery 3 is also connected to motor 5 via inverter 2. Battery 3 discharges when motor 5 is operating and charges when motor 5 is regenerating. In this embodiment, battery 3 is a high-voltage battery. The number of battery modules is not limited to three; it may be one, two, or four or more. 【0011】 Three battery modules M1 to M3 are connected in series, and motors 5 for electric vehicles, etc., are connected to both ends of them via inverters 2. Inverter 2 is a power conversion circuit that converts power between the battery 3 and the motor 5. 【0012】 The relay switch 4 controls the main power supply by switching it ON and OFF, and is connected between the battery 3, the motor 5, and the inverter 2. 【0013】The total voltage sensor 6 is connected between the terminals of both poles of the battery 3 and is a sensor that detects the voltage of the battery 3. The current sensor 7 is connected between the battery 3 and the inverter 2 and detects the current output from the battery 3. The temperature sensor 8 is installed in the battery 3 and detects the temperature of the battery 3. The temperature sensor 8 is installed in multiple locations on the battery 3 so that the temperature of each cell can be detected, and includes at least two sensors. The temperature distribution within the battery 3 is predetermined by the installation location of the battery 3 in the vehicle, the driving environment, etc. The battery controller 100 can detect the temperature of each cell by referring to the temperature distribution data stored in memory and calculating the temperature of each cell from the detected values ​​of at least two temperature sensors 8. The total voltage sensor 6, current sensor 7, and temperature sensor 8 detect the total voltage, current, and temperature of the battery 3 in response to commands from the battery controller 100 and / or the vehicle controller 200, and transmit the detection results to the battery controller 100 and / or the vehicle controller 200. 【0014】 The battery controller 100 is a controller (processor) that manages the state of the battery 3 and controls the charging and discharging of the battery 3, and comprises cell controllers CC1, CC2, CC3, photocouplers PC1, PC2, and a controller (CPU) 10. The three cell controllers CC1, CC2, and CC3 monitor the battery capacity (specifically, the voltage VC1 to VC4 of each individual cell) of the corresponding battery modules M1, M2, and M3. The input terminals VC1 to VC4 of each cell controller CC1 to CC3 are connected to each cell 1 of the battery modules M1 to M3, and the cell controllers CC1 to CC3 are cascaded together. 【0015】 The CPU 10 sends a command to cell controllers CC1 to CC3 to detect the voltage of each cell 1 at a predetermined timing. Upon receiving this command, cell controllers CC1 to CC3 detect the voltage of each cell 1. The detected voltages are stored in memory (not shown) or the like, which are located in each cell controller CC1 to CC3. 【0016】Furthermore, the CPU 10 sends commands to cell controllers CC1 to CC3 to read the voltage of each cell 1 at predetermined timings. Upon receiving these commands, cell controllers CC1 to CC3 read the detected voltages stored in their respective memories and send them back to the CPU 10. 【0017】 Electrically insulating photocouplers PC1 and PC2 are used for communication between the CPU 10 and the cell controllers CC1 to CC3. Each photocoupler PC1 and PC2 has a photodiode PD1 and PD2, which are light-emitting elements, and a phototransistor PT1 and PT2, which are light-receiving elements. 【0018】 Instead of using a photocoupler for communication between the cell controller CC2 and the CPU 10, a so-called cascade communication method is employed, in which data sent from the CPU 10 to cell controller CC3 is sent from cell controller CC3 to cell controller CC2, then from cell controller CC2 to cell controller CC1, and finally this data is sent from cell controller CC1 to the CPU 10 via photocoupler PC2. 【0019】 The vehicle controller 200 is a controller (processor) that controls the entire vehicle, including the drive system including the motor 5 and the auxiliary systems such as lights. The vehicle controller 200 also controls the battery 3 together with the battery controller 100. For example, the vehicle controller 200 limits the output torque of the motor by controlling the inverter 2 in order to prevent over-discharge or over-discharge of the battery 3, according to the State of Charge (SOC) of the battery 3. In the example in Figure 1, the battery controller 100 and the vehicle controller 200 are separate, but the battery controller 100 and the vehicle controller 200 may be combined into a single controller. Also, the detected values ​​of the total voltage sensor 6, current sensor 7, and temperature sensor 8 may be output directly to the battery controller 100. 【0020】Next, the functions of the battery controller 100 will be described with reference to Figure 2. Figure 2 is a block diagram showing an example of a battery controller according to this embodiment. The battery controller 100 has at least the function of managing the state of the battery 3 during charging and discharging, and the function of controlling the charging and discharging of the battery 3. The battery controller 100 acquires detection values ​​from the total voltage sensor 6, the current sensor 7, and the temperature sensor 8, and detects the voltage of the battery 3, the current of the battery 3, and the temperature of the battery 3. 【0021】 The battery controller 100 controls the charging and discharging of the battery 3. When the battery 3 is discharged, there is a risk of polarization due to the discharge. Therefore, after discharge, it is necessary to prohibit charging of the battery 3 until the polarization is resolved. However, in systems that frequently repeat charging and discharging, such as V2H, it is desirable to start charging as soon as possible. Therefore, in this embodiment, the battery controller 100 charges the battery 3 while limiting charging. This makes it possible to shorten the charging time while suppressing overvoltage of the battery 3. The functions of the battery controller 100 will be described in detail below. In the following description, the example will be given of a scenario in which the battery 3 is discharged after being fully charged, but in this embodiment, it is not limited to a scenario in which polarization occurs due to discharge. 【0022】 As shown in Figure 2, the battery controller 100 has functional blocks including a state acquisition unit 11, a charge setting unit 12, a SOC calculation unit 13, a flag setting unit 14, and a charge / discharge control unit 15. Programs for realizing each function in each functional block are stored in memory. The processor included in the battery controller 100 then executes the programs to realize each function of the functional block. Note that the number of functional blocks is not limited to five; it may be one to four or six or more functional blocks. 【0023】The status acquisition unit 11 acquires the status of the battery 3. The status acquisition unit 11 acquires the status of the battery 3 at regular intervals. In this embodiment, the status of the battery 3 includes the current value of the battery 3, the current amount of the battery 3, the capacity degradation rate of the battery 3, and the temperature of the battery 3. For example, the status acquisition unit 11 acquires the discharge state of the battery 3 while it is discharging. The discharge state includes the current value and / or current amount of the battery 3 during discharge. The current amount during discharge is calculated based on the current value and discharge time during discharge. The current amount during discharge is also called the discharge amount. Furthermore, the capacity degradation rate and temperature of the battery 3 include, for example, the capacity degradation rate and temperature of the battery 3 after discharge. The status acquisition unit 11 of the battery 3 may also acquire the charge state of the battery 3. The charge state includes the current value and / or current amount of the battery 3 during charging. The information including the status of the battery 3 acquired by the status acquisition unit 11 is output to the charge setting unit 12. 【0024】 The charging setting unit 12 sets a charging plan for charging the battery 3. The charging plan includes the charging time, charging power, etc., for charging the battery 3. In this embodiment, if charging is performed after the battery 3 has been discharged, the charging setting unit 12 sets a limited charging plan to limit the charging of the battery 3. The limited charging plan includes a predetermined time for limiting the charging of the battery 3 (also referred to as the charging limit time), and the limited charging power (limited charging power) for charging the battery 3 while its charging is limited. The charging setting unit 12 sets the limited charging plan based on the state of the battery 3. The charging plan set by the charging setting unit 12 is output to the charge / discharge control unit 15. 【0025】 First, let's explain an example of setting a predetermined time based on the discharge state. The charging setting unit 12 sets a predetermined time based on the current value of the battery 3 while it is discharging. Specifically, the charging setting unit 12 sets a longer predetermined time the larger the current value. In addition, the charging setting unit 12 sets a predetermined time based on the amount of discharge of the battery 3 while it is discharging. Specifically, the charging setting unit 12 sets a longer predetermined time the larger the amount of discharge. 【0026】 The charging setting unit 12 may set a predetermined time based on the capacity degradation rate of the battery 3. The capacity degradation rate of the battery 3 is the so-called SOH (State of Health). SOH is determined by the ratio of the current battery capacity to the initial battery capacity. The charging setting unit 12 sets a longer predetermined time the smaller the SOH. The charging setting unit 12 may also set a predetermined time based on the temperature of the battery 3. Specifically, the charging setting unit 12 sets a longer predetermined time the lower the temperature of the battery 3. In addition, the discharge state of the battery 3 may be used, as well as both the capacity degradation rate and temperature of the battery 3, or either one of them may be used to set the predetermined time. 【0027】 Here, an example of setting a predetermined time using the battery control device according to this embodiment will be explained using Figure 3. Figure 3 is a diagram for explaining the correspondence between the State of Health (SOH) of the battery, the current value during discharge, the discharge amount, the temperature, and the depolarization time. The depolarization time is the time required to eliminate the polarization of the battery 3, and it varies depending on the state of the battery 3, such as the SOH, the current value during discharge, the discharge amount, and the temperature. The correspondence between the state of the battery 3 and the depolarization time is obtained in advance by experimentation or analysis. Figure 3 shows a table showing the correspondence between the discharge amount of the battery 3, the temperature of the battery 3, and the depolarization time for each combination of the SOH of the battery 3 and the current value during discharge. For example, the upper left diagram of Figure 3 shows a table showing the correspondence between the discharge amount of the battery 3, the temperature of the battery 3, and the depolarization time when the SOH is 100% and the current value during discharge is 10A. The charging setting unit 12 refers to the correspondence between the state of the battery 3 and the depolarization time, as shown in the table in Figure 3, and obtains the depolarization time based on the state of the battery 3 and sets the depolarization time to a predetermined time (limited charging time). 【0028】Next, an example of setting the limited charging power will be described. The charging setting unit 12 sets the limited charging power to be smaller than the normal charging power. The normal charging power is the charging power required to charge the battery 3 when charging of the battery 3 is not restricted. For example, the charging setting unit 12 obtains the state of charge (SOC) and depolarization time of the battery 3 and sets the limited charging power based on the SOC and depolarization time of the battery 3. Specifically, the charging setting unit 12 sets the limited charging power to be smaller the larger the SOC of the battery 3. Also, the charging setting unit 12 sets the limited charging power to be smaller the longer the depolarization time. The SOC of the battery 3 may be the result of the SOC calculation unit 13 described later. The depolarization time is determined based on the state of the battery 3, by referring to the correspondence between the state of the battery 3 and the depolarization time as shown in Figure 3. 【0029】 Here, an example of limiting the charging power by the battery control device according to this embodiment will be explained using Figure 4. Figure 4 is a diagram for explaining the correspondence between the combination of the battery's SOC and depolarization time and the charging power at the time of limitation. The table in Figure 4 shows the correspondence between the combination of SOC and depolarization time and the charging power at the time of limitation (limited charging power). The charging setting unit 12 sets the charging power at the time of limitation by referring to the correspondence between the combination of SOC and depolarization time and the charging power at the time of limitation, as shown in the table in Figure 4. 【0030】 The SOC calculation unit 13 calculates the State of Charge (SOC) of the battery 3 by integrating the charge and discharge currents of the battery 3. The SOC calculation unit 13 also has a map showing the correlation between the voltage of cell 1 and the SOC, and calculates the SOC of the battery 3 from the lowest voltage of multiple cells 1 by referring to this map. 【0031】In this embodiment, the SOC calculation unit 13 calculates the amount of SOC decrease after the battery 3 is fully charged. The amount of SOC decrease is the difference between the SOC at full charge and the SOC calculated at regular intervals after full charge. First, the SOC calculation unit 13 calculates the SOC when the battery 3 is fully charged. The actual SOC at the time of full charge becomes the SOC at full charge. Whether or not the battery 3 is fully charged is determined by the full charge flag. Next, the SOC calculation unit 13 calculates the SOC at regular intervals. The SOC for each calculation becomes the actual SOC. The SOC calculation unit 13 calculates the difference between the SOC at full charge and the actual SOC as the amount of SOC decrease. If the battery 3 is discharging after full charge, the amount of SOC decrease will be larger. The SOC and the amount of SOC decrease calculated by the SOC calculation unit 13 are output to the flag setting unit 14. 【0032】 Here, the method by which the SOC calculation unit 13 calculates the amount of SOC decrease from a fully charged state of charge of the battery 3 will be explained using Figure 5. Figure 5 is a flowchart of the control flow of the calculation method for the amount of SOC decrease from a fully charged state of charge of the battery according to this embodiment. The SOC calculation unit 13 repeatedly executes the control flow shown in Figure 5 at a constant period. In Figure 5, the fully charged flag is set to "1" or "0". "1" indicates that the battery 3 is in a fully charged state. "0" indicates that the battery 3 is not in a fully charged state. The SOC flag when fully charged is set to "1" or "0". "1" indicates that the SOC of the battery 3 when fully charged is not set to 0. "0" indicates that the SOC of the battery 3 when fully charged is set to 0. 【0033】In step S1, the SOC calculation unit 13 determines whether the full charge flag is set to 1. If the full charge flag is set to 1, the SOC calculation unit 13 proceeds to step S2. If the full charge flag is not set to 1, the SOC calculation unit 13 proceeds to step S6. In step S2, the SOC calculation unit 13 determines whether the SOC flag at full charge is set to 0. If the SOC flag at full charge is set to 0, the SOC calculation unit 13 proceeds to step S3. If the SOC flag at full charge is not set to 0, the SOC calculation unit 13 proceeds to step S5. 【0034】 In step S3, the SOC calculation unit 13 sets the SOC at full charge to the actual SOC. In step S4, the SOC calculation unit 13 sets the SOC flag at full charge to 1. In step S5, the SOC calculation unit 13 calculates ΔSOC by subtracting the actual SOC from the SOC at full charge. In step S6, the SOC calculation unit 13 sets ΔSOC to 0. In step S7, the SOC calculation unit 13 sets the SOC flag at full charge to 0. In step S8, the SOC calculation unit 13 sets the SOC at full charge to 0. 【0035】The flag setting unit 14 sets a full charge flag to indicate whether the battery 3 is fully charged or not. The full charge flag can be set to an on state or an off state. The full charge flag is set to an on state when the battery 3 is fully charged. When the full charge flag is on, recharging is prohibited. The full charge flag is also called the recharging prohibition flag. The full charge flag is set to an off state when the battery 3 is not fully charged. For example, the off state of the full charge flag is represented by "0" and the on state by "1". When the battery 3 is charged while an external charger is connected to the vehicle and the battery 3 becomes fully charged, the flag setting unit 14 sets the full charge flag to an on state (full charge flag = 1). When the full charge flag is set to an on state, the flag setting unit 14 maintains the full charge flag in an on state as long as an external charger is connected to the vehicle, unless a release check is performed. When a release check is performed, the flag setting unit 14 sets the full charge flag to an off state (full charge flag = 0). The fully charged flag set by the flag setting unit 14 is output to the charge / discharge control unit 15. 【0036】 The release determination will now be explained. The flag setting unit 14 compares the amount of SOC decrease (ΔSOC) calculated by the SOC calculation unit 13 with a predetermined threshold and determines whether or not to release the full charge flag depending on whether the amount of SOC decrease (ΔSOC) of the battery 3 is equal to or greater than the predetermined threshold. The flag setting unit 14 makes a release determination to release the full charge flag if the amount of SOC decrease (ΔSOC) of the battery 3 is equal to or greater than the predetermined threshold. If the amount of SOC decrease of the battery 3 is less than the predetermined threshold, the flag setting unit 14 does not make a release determination and continues to monitor the SOC of the battery 3. For example, the predetermined threshold is set to 1%. 【0037】Here, the method by which the flag setting unit 14 sets the full charge flag due to a decrease in the SOC of the battery 3 will be explained using Figure 6. Figure 6 is a flowchart showing the control flow of the method for setting the full charge flag due to a decrease in the SOC of the battery according to this embodiment. The flag setting unit 14 repeatedly executes the control flow shown in Figure 6 at a constant cycle. In step S11, the flag setting unit 14 determines whether the full charge flag is set to 1. If the full charge flag is set to 1, the flag setting unit 14 proceeds to step S12. If the full charge flag is not set to 1, the flag setting unit 14 terminates the control flow shown in Figure 6. In step S12, the flag setting unit 14 determines whether ΔSOC is greater than 1%. If ΔSOC is determined to be greater than 1%, the flag setting unit 14 proceeds to step S13. If ΔSOC is not determined to be greater than 1%, the flag setting unit 14 terminates the control flow shown in Figure 6. In step S13, the flag setting unit 14 sets the full charge flag to 0. When the flag setting unit 14 sets the full charge flag to 0, the control flow ends. 【0038】 The charge / discharge control unit 15 controls the charging and discharging of the battery 3. Based on the charging plan, the charge / discharge control unit 15 sends a control command to an external charger to charge the battery 3 using the normal charging power that is normally used when charging the battery 3. The external charger receives the control command from the battery controller 100 and outputs power to the battery 3 through the charging cable according to the charging plan included in the control command. The charge / discharge control unit 15 repeatedly determines whether the battery 3 is fully charged, and terminates the charging control when the battery 3 is fully charged. 【0039】In this embodiment, the charge / discharge control unit 15 restricts charging of the battery 3 for a predetermined period of time after the battery 3 has finished discharging. For example, the charge / discharge control unit 15 prohibits charging of the battery 3 until a predetermined period of time has elapsed, and then charges the battery 3 with normal charging power after the predetermined period of time has elapsed. Alternatively, the charge / discharge control unit 15 may charge the battery 3 with limited charging power until a predetermined period of time has elapsed, and then charge the battery 3 with normal charging power after the predetermined period of time has elapsed. 【0040】 Furthermore, when an external charger is connected to the vehicle, the charge / discharge control unit 15 starts charging the battery 3 and continues charging the battery 3 until it is fully charged. The battery 3 is normally charged using the charging power. When the battery 3 is fully charged, the charge / discharge control unit 15 stops charging the battery 3 and outputs a full charge flag to the SOC calculation unit 13 to indicate that the battery 3 is fully charged. The charge / discharge control unit 15 also prohibits charging the battery 3 while the full charge flag is set to the ON state, indicating that the battery 3 is fully charged. 【0041】 Here, we will explain an example of how the charge / discharge control unit 15 limits the charging of the battery 3. As an example, consider a scenario where the battery 3 is discharged after it has reached a fully charged state. When an external charger is connected to the vehicle, the charge / discharge control unit 15 starts charging the battery 3 and continues charging until the battery 3 reaches a fully charged state. When the battery 3 reaches a fully charged state, the charge / discharge control unit 15 outputs a full charge flag to the SOC calculation unit 13 to indicate that the battery 3 is fully charged. When the SOC calculation unit 13 receives this full charge flag, it starts calculating the amount of SOC decrease. Here, if the fully charged battery 3 starts discharging, the SOC will start to decrease. Examples of when the fully charged battery 3 starts discharging include air conditioning and V2H. The battery 3 discharges for air conditioning or V2H while the vehicle is parked at home or elsewhere. 【0042】When the amount of decrease in the SOC of the battery 3 becomes equal to or greater than a predetermined threshold, the flag setting unit 14 determines that the full charge flag is to be released. The flag setting unit 14 outputs a full charge flag indicating that the battery 3 is not in the full charge state to the charge / discharge control unit 15. When the full charge flag indicating that the battery 3 is not in the full charge state is input, the charge / discharge control unit 15 performs charging (recharging) of the battery 3 after the discharge of the battery 3 is completed. 【0043】 Next, an example of the charge control of the battery 3 according to the present embodiment will be described with reference to FIG. 7. FIG. 7 is a diagram showing an example of the charge limit of the battery according to the present embodiment. In FIG. 7, a graph showing the transition of the charging power for charging the battery 3 is shown. The horizontal axis represents the charging time, and the vertical axis represents the charging power. As shown in FIG. 7, the charge / discharge control unit 15 charges the battery 3 with the limited charging power E1 during the charge limit time P1, that is, until the time point t1. The charge / discharge control unit 15 charges the battery 3 with the normal charging power E2 during the period P2 from the time point t1 when the charge limit time P1 ends. 【0044】 Further, in the present embodiment, in a scenario where the charge / discharge control unit 15 continuously repeats the charge / discharge of the battery 3, after the discharge of the battery 3 is completed, the charge of the battery 3 is limited until a predetermined time elapses. A scenario where the charge / discharge of the battery 3 is continuously repeated is, for example, a scenario where V2H is performed. 【0045】Here, the charge control for depolarizing the battery 3 by the charge / discharge control unit 15 will be explained using Figure 8. Figure 8 is a flowchart showing the control flow of the charge control method for depolarizing the battery 3 according to this embodiment. In step S21, the battery controller 100 determines whether the discharge current is greater than 10A. The discharge current is the current value during discharge. If it is determined that the discharge current is greater than 10A, the battery controller 100 proceeds to step S22. If it is not determined that the discharge current is greater than 10A, the battery controller 100 proceeds to step S26. In step S22, the battery controller 100 clears the counter. In step S23, the battery controller 100 sets the charge limit flag to 1. The charge limit flag indicates whether or not the charging of the battery 3 is being restricted. The charge limit flag is set to "1" or "0". "1" indicates that the charge limit flag is on and the charging of the battery 3 is being restricted. "0" indicates that the charge limit flag is off and the charging of the battery 3 is not being restricted. In step S24, the battery controller 100 sets a predetermined time. For example, the predetermined time is set based on the current value, discharge time, temperature, and capacity degradation rate. In step S25, the battery controller 100 sets the limited charging power. For example, the limited charging power is set based on the depolarization time and SOC. The charging limit flag is cleared and turned off when the system is shut down. 【0046】In step S26, the battery controller 100 determines whether the charging current is greater than 1 A. If it is determined that the charging current is greater than 1 A, the battery controller 100 proceeds to step S27. If it is determined that the charging current is not greater than 1 A, the battery controller 100 ends the control flow. In step S27, the battery controller 100 determines whether the value of the counter is greater than a predetermined time. If it is determined that the value of the counter is greater than the predetermined time, the battery controller 100 proceeds to step S28. If it is not determined that the value of the counter is greater than the predetermined time, the battery controller 100 proceeds to step S29. In step S28, the battery controller 100 sets the charge limit flag to 0. 【0047】 Next, a battery control method by the battery controller 100 will be described with reference to FIG. 9. FIG. 9 is a flowchart showing a control flow of the battery control method by the battery controller according to the present embodiment. Note that the control flow shown in FIG. 9 is executed, for example, when the discharge of the battery 3 starts. 【0048】 In step S31, the battery controller 100 acquires the discharge state of the battery 3 while the battery 3 is discharging. In step S32, the battery controller 100 determines whether the discharge of the battery 3 has ended. If it is determined that the discharge of the battery 3 has ended, the battery controller 100 proceeds to step S33. If it is determined that the discharge of the battery 3 has not ended, the battery controller 100 returns to step S31 and acquires the discharge state while the battery 3 is discharging. In step S33, the battery controller 100 sets a predetermined time based on the discharge state. In step S34, the battery controller 100 restricts the charging of the battery 3. For example, the battery controller 100 charges the battery 3 with a restricted charging power for a predetermined time. When the charging of the battery 3 ends, the battery controller 100 ends the control flow shown in FIG. 9. 【0049】As described above, in the battery control device and battery control method according to this embodiment, the controller acquires the discharge state of the battery while it is discharging, sets a predetermined time based on the discharge state, and restricts battery charging until the predetermined time has elapsed after the battery has finished discharging. This makes it possible to charge the battery after it has been discharged more appropriately. 【0050】 Furthermore, in the battery control device and battery control method according to this embodiment, the controller sets the limiting charging power for charging the battery when charging is restricted to a lower value than the normal charging power for charging the battery when charging is not restricted, and controls the charging of the battery based on the limiting charging power for a predetermined time after the battery discharge is completed. As a result, charging can be performed while suppressing the battery from becoming overvoltage while charging is being controlled, and the charging time can be shortened compared to prohibiting charging altogether while charging is being controlled. 【0051】 Furthermore, in the battery control device and battery control method according to this embodiment, the controller acquires the battery's capacity degradation rate and sets a predetermined time based on the capacity degradation rate. This allows for more appropriate charging of the battery after discharge. 【0052】 Furthermore, in the battery control device and battery control method according to this embodiment, the controller acquires the battery temperature and sets a predetermined time based on the temperature. This allows for more appropriate charging of the battery after discharge. 【0053】Furthermore, in the battery control device and battery control method according to this embodiment, the battery is a battery mounted in a vehicle, and when the battery is charged while an external charger is connected to the vehicle and the battery reaches a fully charged state, the controller sets a fully charged flag to the ON state to indicate that the battery is fully charged. When the fully charged flag is set to the ON state, the controller maintains the fully charged flag in the ON state as long as the external charger is connected to the vehicle, unless a release determination is made, and sets the fully charged flag to the OFF state when a release determination is made. As a result, even after the battery has been charged once and reached a fully charged state, it is possible to charge it again, making it possible to repeatedly perform charging and discharging. 【0054】 Furthermore, in the battery control device and battery control method according to this embodiment, the controller acquires the battery's State of Charge (SOC) and performs a release determination when the SOC drops below a predetermined value. This prevents the full charge flag from being mistakenly released regardless of the actual state of the battery, even when the battery is fully charged. 【0055】 Furthermore, in the battery control device and battery control method according to this embodiment, the battery is a high-voltage battery, and the controller restricts battery charging for a predetermined period of time after the battery has finished discharging, in situations where the battery is repeatedly charged and discharged. This prevents the battery from becoming overvoltage due to charging after discharge in situations where a high-voltage battery is repeatedly charged and discharged, such as when V2H is performed. 【0056】 The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. 【0057】1...Cell 2...Inverter 3...Battery 4...Relay switch 5...Motor 6...Total voltage sensor 7...Current sensor 8...Temperature sensor 100...Battery controller 11...Status acquisition unit 12...Charging setting unit 13...SOC calculation unit 14...Flag setting unit 15...Charge / discharge control unit 200...Vehicle controller

Claims

1. A battery control device comprising a controller, wherein the controller acquires the discharge state of the battery while the battery is being discharged, sets a predetermined time based on the discharge state, and restricts the charging of the battery from the time after the battery has finished discharging until the predetermined time has elapsed.

2. A battery control device according to claim 1, wherein the controller sets a limiting charging power for charging the battery when charging of the battery is restricted to a lower value than the normal charging power for charging the battery when charging of the battery is not restricted, and controls the charging of the battery based on the limiting charging power for a predetermined time after the discharge of the battery is completed.

3. A battery control device according to claim 1 or 2, wherein the controller acquires the capacity degradation rate of the battery and sets the predetermined time based on the capacity degradation rate.

4. A battery control device according to any one of claims 1 to 3, wherein the controller acquires the temperature of the battery and sets the predetermined time based on the temperature.

5. A battery control device according to any one of claims 1 to 4, wherein the battery is a battery mounted on a vehicle, and the controller sets a full charge flag to the ON state when the battery is charged while an external charger is connected to the vehicle and the battery becomes fully charged, and when the full charge flag is set to the ON state, maintains the full charge flag in the ON state as long as an external charger is connected to the vehicle unless a release determination is made, and sets the full charge flag to the OFF state when a release determination is made.

6. A battery control device according to claim 5, wherein the controller acquires the State of Control (SOC) of the battery and performs the release determination when the SOC falls to a predetermined value or more.

7. A battery control device according to any one of claims 1 to 6, wherein the battery is a high-voltage battery, and the controller is a battery control device that, in a scenario in which the charging and discharging of the battery is repeatedly performed continuously, limits the charging of the battery for a predetermined time after the discharge of the battery has finished.

8. A battery control method performed by a controller, wherein the controller acquires the discharge state of the battery while the battery is being discharged, sets a predetermined time based on the discharge state, and restricts the charging of the battery after the battery has finished discharging until the predetermined time has elapsed.

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