JP2018151175A - Estimation device, estimation method, and estimation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an estimation device, an estimation method, and an estimation program with which it is possible to improve the accuracy of estimating the SOC value of a secondary battery.SOLUTION: The estimation device pertaining to an embodiment comprises an observation value acquisition unit, an arithmetic unit, and a storage unit. The arithmetic unit estimates, on the basis of an observation value acquired by the observation value acquisition unit, an SOC value that indicates the state of charge of a secondary battery by estimation computation using an equivalent circuit of the secondary battery. When a stop time until stopping is terminated after use of the secondary battery is stopped is greater than or equal to a preset time, the arithmetic unit starts estimation computation, with a value determined on the basis of an observed voltage value as the initial SOC value in estimation computation, and when the stop time is less than the preset time, starts estimation computation, with a value determined depending on whether or not a previous SOC value that is an SOC value stored in the storage unit before use of the secondary battery is stopped, as the initial value.SELECTED DRAWING: Figure 5

Description

  Embodiments disclosed herein relate to an estimation apparatus, an estimation method, and an estimation program.

  Conventionally, for example, an electric vehicle such as a hybrid vehicle or an electric vehicle has been equipped with a power source that supplies electric power to a motor that is a power source. A chargeable / dischargeable secondary battery that stores regenerative power is used.

  In general, an electric vehicle is equipped with an estimation device that estimates an SOC (State Of Charge) value so that electric power from the secondary battery can be stably supplied to the motor. The SOC value is a value indicating the state of charge of the secondary battery. As a method of estimating the SOC value, a method of estimating the SOC value using an equivalent circuit model in which the secondary battery is regarded as an electric circuit is known. Yes.

  By the way, in the secondary battery, polarization occurs inside by charging / discharging, and it may take a long time of several tens of minutes to several tens of hours until the polarization is eliminated and stabilized. For this reason, even when charging / discharging is not performed, the polarization voltage may be superimposed on the voltage of the secondary battery, and the estimation accuracy of the SOC value may be reduced. Thus, a technique has been proposed in which an SOC initial value is changed in an estimation device that estimates an SOC value in accordance with the length of a power system stop time until a power system including a secondary battery is activated.

  For example, the estimation device described in Patent Literature 1 determines the SOC initial value from the voltage of the secondary battery when the stop time until the power supply system is started has passed the first stop period. Before the first stop period elapses, the SOC initial value is determined by another method.

  Specifically, the estimation device stores the SOC value calculated by the previous estimation in the storage unit, and is before the second stop period in which the stop time of the power supply system is shorter than the first stop period. In this case, the SOC value stored in the storage unit is set as the SOC initial value. In addition, when the stop time of the power supply system has elapsed after the second stop period and before the first stop time has elapsed, the estimation device can determine from the voltage of the secondary battery observed when the power supply system is stopped. The initial SOC value is obtained.

JP 2008-145349 A

  However, in the estimation apparatus described in Patent Literature 1, when the power system is stopped before the second stop period elapses, the SOC value stored in the storage unit is not valid due to data corruption or the like. In this case, the SOC initial value becomes indefinite, and there is a possibility that the estimation accuracy of the SOC value is lowered.

  One aspect of the embodiments has been made in view of the above, and an object thereof is to provide an estimation device, an estimation method, and an estimation program that can improve the estimation accuracy of the SOC value.

  An estimation apparatus according to an aspect of the embodiment includes an observation value acquisition unit, a calculation unit, and a storage unit. The observed value acquisition unit acquires observed values of the voltage and current of the secondary battery. The calculation unit estimates an SOC value indicating a charge state of the secondary battery by an estimation calculation using an equivalent circuit model of the secondary battery based on the observation value acquired by the observation value acquisition unit. The storage unit stores the SOC value estimated by the calculation unit. When the stop time from when the use of the secondary battery is stopped to when the stop is released is equal to or longer than a preset time, the arithmetic unit determines a value determined based on the observed value of the voltage When the estimation calculation is started as an initial value of the SOC value in the estimation calculation and the stop time is less than the preset time, the storage unit stores the storage unit before the use of the secondary battery is stopped. The estimation calculation is started with a value determined according to whether or not the previous SOC value, which is an SOC value, is valid, as the initial value.

  According to one aspect of the embodiment, it is possible to provide an estimation device, an estimation method, and an estimation program that can improve the estimation accuracy of the SOC value.

FIG. 1 is a diagram illustrating a configuration example of a vehicle-mounted system including an estimation device according to an embodiment. FIG. 2 is a diagram showing the relationship between the elapsed time from the stop timing and the SOC initial value used in the estimation calculation of the charge state estimation unit. FIG. 3 is an explanatory diagram illustrating an example of an equivalent circuit model of a secondary battery. FIG. 4 is a diagram illustrating an example of SOC-OCV characteristics of the secondary battery. FIG. 5 is a functional block diagram of the charging state estimation unit. FIG. 6 is a diagram illustrating an example of a table indicating SOC-OCV characteristics. FIG. 7 is a diagram showing the relationship between the first variation range and the OCV value in the charging information. FIG. 8 is a diagram illustrating the relationship between the second variation range and the OCV value in the discharge time information. FIG. 9 is a flowchart illustrating an example of a processing procedure executed by the charge state estimation unit. FIG. 10 is a flowchart showing an example of the process of step S11 of FIG.

  Hereinafter, embodiments of an estimation device, an estimation method, and an estimation program disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below. In the following, a vehicle-mounted system will be described as an application example of a power supply system including an estimation device, but the present invention is not limited to this example. For example, a power supply system including an estimation device can be applied in addition to the on-vehicle system, such as a power generation system that converts natural energy such as sunlight or wind power into electric power.

[1. Configuration of on-board system]
FIG. 1 is a diagram illustrating a configuration example of a vehicle-mounted system including an estimation device according to an embodiment. The vehicle mounting system 100 shown in FIG. 1 is mounted on a vehicle such as a hybrid vehicle (HEV: Hybrid Electric Vehicle) and an electric vehicle (EV: Electric Vehicle) (not shown).

  The on-vehicle system 100 includes a power supply system 1, a vehicle control device 2, a motor 3, and a power conversion unit 4. The vehicle control device 2 starts the power supply system 1, connects the power supply system 1 and the power conversion unit 4, and drives the power conversion unit 4 to control the motor 3.

  The power conversion unit 4 can convert DC power from the power supply system 1 into AC power and output it to the motor 3, and converts AC power that is regenerative power of the motor 3 into DC power to convert the power into the power system 1. Can be supplied to.

  The vehicle control device 2 can control charging / discharging of the secondary battery 5 based on an SOC (State Of Charge) value indicating a state of a secondary battery 5 described later notified from the power supply system 1. For example, the vehicle control device 2 can increase the SOC value by supplying regenerative power of the motor 3 to the power supply system 1 when the SOC value decreases. The SOC value is the charging rate (%) of the secondary battery 5, but may be the remaining capacity (Ah) of the secondary battery 5.

  The power supply system 1 includes a secondary battery 5, a battery monitoring system 6, and a relay 7. The secondary battery 5 is, for example, a lithium ion secondary battery or a nickel hydride secondary battery. The secondary battery 5 is, for example, an assembled battery, and is configured by connecting a plurality of battery blocks in series. Each battery block includes a plurality of battery cells connected in series. The secondary battery 5 may be configured by connecting a plurality of battery blocks in parallel.

  The battery monitoring system 6 brings the power supply system 1 into an operating state when an ignition switch (not shown) provided in the vehicle is turned on. When the power supply system 1 is in an operating state, the secondary battery 5 is connected to the power conversion unit 4 and the SOC value estimation process of the secondary battery 5 is repeatedly performed. The battery monitoring system 6 notifies the vehicle control device 2 of the estimated SOC value every time the SOC value is estimated.

  Further, the battery monitoring system 6 puts the power supply system 1 in a stopped state when the ignition switch is turned off. When the power supply system 1 is in the stopped state, the secondary battery 5 is disconnected from the power conversion unit 4 and the SOC value estimation process of the secondary battery 5 is stopped.

  The battery monitoring system 6 has a block monitoring unit (not shown) provided in each of a plurality of battery blocks constituting the secondary battery 5, and each block monitoring unit has an abnormality of a corresponding battery block, etc. Can be detected.

  The battery monitoring system 6 includes a battery state monitoring unit 10, a voltage sensor 11 that detects an instantaneous value of the voltage u across the secondary battery 5 (hereinafter referred to as a voltage observation value u), and a current flowing through the secondary battery 5. a current sensor 12 that detects an instantaneous value of i (hereinafter referred to as a current observation value i).

The battery state monitoring unit 10 includes a switch control unit 20 and a charge state estimation unit 21 (an example of an estimation device). The switch control unit 20 controls ON / OFF of the relay 7 based on an ignition signal _SIGN indicating the state of the ignition switch.

For example, when the ignition signal _SIGN indicates ON of the ignition switch, the switch control unit 20 turns on the relay 7 to connect the secondary battery 5 to the power conversion unit 4, and the vehicle-mounted system 100 uses the secondary battery 5. Make it available for use. Further, when the ignition signal _SIGN indicates that the ignition switch is OFF, the switch control unit 20 turns off the relay 7 to disconnect the secondary battery 5 from the power conversion unit 4, and the vehicle-mounted system 100 detects the secondary battery 5. Stop using.

  The switch control unit 20 can also control ON / OFF of the relay 7 in response to a request from the vehicle control device 2. Further, when the switch control unit 20 detects an abnormality in the secondary battery 5 in a state where the relay 7 is ON, the switch control unit 20 can also turn off the relay 7 to stop the power supply system 1.

  When the power supply system 1 is in the operating state, the charging state estimation unit 21 performs an estimation calculation that estimates the SOC value of the secondary battery 5. For example, the charging state estimation unit 21 determines the charging state of the secondary battery 5 using the equivalent circuit model of the secondary battery 5 based on the voltage observation value u and the current observation value i acquired from the voltage sensor 11 and the current sensor 12. An estimation operation is performed to estimate the indicated SOC value. The charging state estimation unit 21 stops the estimation calculation of the SOC value when the power supply system 1 is in the stopped state.

  The charge state estimation unit 21 outputs the SOC value, which is the result of the estimation calculation, to the vehicle control device 2 every time the estimation calculation is performed. Further, the charging state estimation unit 21 repeatedly stores the SOC value, which is the result of the estimation calculation, in the internal storage unit.

  The secondary battery 5 is polarized internally by charging and discharging, and it takes time until the polarization is eliminated and stabilized. For this reason, even when charging / discharging is not performed, the polarization voltage may be superimposed on the voltage of the secondary battery 5, which may reduce the estimation accuracy of the SOC value.

  Therefore, the charging state estimation unit 21 is configured to have a preset time T1 (hereinafter sometimes referred to as a set time T1) after the power supply system 1 is stopped and the use of the secondary battery 5 is stopped. It is determined whether the power supply system 1 is activated and the use of the secondary battery 5 is resumed. Based on the determination result, the state-of-charge estimating unit 21 changes the initial SOC value (hereinafter referred to as the SOC initial value) used in the SOC value estimation calculation. The set time T1 is a time longer than the time required for depolarizing the secondary battery 5.

  FIG. 2 shows the elapsed time from the timing when the power supply system 1 is stopped and the use of the secondary battery 5 is stopped (hereinafter referred to as stop timing), and the SOC initial value used in the estimation calculation of the charge state estimation unit 21. It is a figure which shows the relationship.

  As shown in FIG. 2, after the set time T1 has elapsed from the stop timing (time t10) and the polarization has disappeared (time t11), the charging state estimation unit 21 starts up the power supply system 1 and the secondary battery 5 When the timing at which the use is resumed (hereinafter referred to as the start timing) occurs, the SOC estimation calculation is executed using the first initial value as the SOC initial value.

  The first initial value is, for example, a value determined from a voltage observation value u acquired from the voltage sensor 11 by SOC-OCV (Open Circuit Voltage) characteristics or the like. OCV is the voltage of the secondary battery 5 in the no-load state, that is, the open circuit voltage of the secondary battery 5, and hereinafter, the value of OCV is referred to as the OCV value.

  In addition, when the start timing occurs before the set time T1 has elapsed from the stop timing (time t10), the charge state estimation unit 21 uses the second initial value or the third initial value as the SOC initial value. The estimation operation is executed.

  The second initial value is an SOC value that is estimated and calculated before the stop timing, and is, for example, an SOC value that is calculated by the last estimation calculation immediately before the stop timing. Hereinafter, the second initial value may be referred to as the last SOC last value. The third initial value is a value determined by the SOC-OCV characteristic or the like from the voltage observation value u acquired from the voltage sensor 11, for example.

  The charge state estimation unit 21 determines whether or not the second initial value is valid. In such processing, the charging state estimation unit 21 determines that the second initial value is not valid, for example, when the second initial value is not within the normal range or when there is data corruption in the second initial value.

  When it is determined that the second initial value is valid, the charging state estimation unit 21 performs an estimation calculation using the second initial value as the SOC initial value, and when it is determined that the second initial value is not valid, The estimation calculation is performed using the third initial value as the SOC initial value.

  As described above, when the use of the secondary battery 5 is resumed before the set time T1 elapses after the use of the secondary battery 5 is stopped, the state-of-charge estimation unit 21 is valid. Depending on whether or not, the SOC initial value is changed. Therefore, when the last SOC last value is not valid, the estimation accuracy of the SOC value can be improved compared to the case where the last SOC last value is used as the SOC initial value. Hereinafter, the charge state estimation unit 21 which is an example of the estimation device will be described in more detail.

[2. Charge state estimation unit 21]
The charge state estimation unit 21 performs an estimation calculation for estimating the SOC value by applying a Kalman filter to an equivalent circuit model obtained by modeling the secondary battery 5.

  FIG. 3 is an explanatory diagram illustrating an example of an equivalent circuit model of the secondary battery 5. As shown in FIG. 3, the equivalent circuit model 30 of the secondary battery 5 includes a power supply 31, a resistance element 32, a first RC circuit 33, and a second RC circuit 34.

  The power supply 31 is an ideal power supply with no internal impedance, and the voltage value of the power supply 31 is the voltage value of the secondary battery 5 in the no-load state, which is the OCV value described above. In the example shown in FIG. 3, the OCV value at the time of charging is represented as OCVa, and the OCV value at the time of discharging is represented as OCVb.

  The resistance element 32 is a resistance element having a resistance value R <b> 0, and the voltage u <b> 0 of the resistance element 32 increases in direct proportion to the change in the current i flowing through the secondary battery 5. The first RC circuit 33 is a parallel circuit of a resistance element having a resistance value R1 and a capacitor having a capacitance C1, and the voltage u1 of the first RC circuit 33 is caused by a change in the current i flowing through the secondary battery 5. On the other hand, it changes transiently.

  The second RC circuit 34 is a parallel circuit of a resistance element having a resistance value R2 and a capacitor having a capacitance C2, and the voltage u2 of the second RC circuit 34 varies with a change in the current i flowing through the secondary battery 5. On the other hand, it changes transiently.

The both-ends voltage u of the equivalent circuit model 30 shown in FIG. 3 can be expressed by the sum of the OCV value, the voltage u0, the voltage u1, and the voltage u2, as shown in the following formula (1).

The voltage u0 can be expressed by the following formula (2) from the current i flowing through the secondary battery 5 and the resistance value R0. The differential equation between the voltage u1 of the first RC circuit 33 and the voltage u2 of the second RC circuit 34 can be expressed as shown in the following formulas (3) and (4).

The charge state estimation unit 21 estimates the SOC value by the estimation calculation using the equivalent circuit model 30 described above. The following formulas (5) and (6) show a system model representing the state of the secondary battery 5. Equation (5) is a state equation indicating the state of the secondary battery 5, and Equation (6) is an observation equation relating to the observed value of the secondary battery 5. In the following formulas (5) and (6), “k” represents a discretized time index (k-th time; hereinafter, sometimes referred to as time k).

In the above formulas (5) and (6), “x _k ” is a state vector indicating the state of the secondary battery 5 at time k, and as shown in the above formula (7), the SOC value and voltage at time k. u1 and voltage u2. Further, “i _k ” is the above-described current observation value i that is a control input from the outside, and “y _k ” is the voltage u across the secondary battery 5 at time k as shown in the above equation (8). It is. “A”, “B”, “C”, and “D” are, for example, matrices obtained from (1) to (4) above.

“V _k ” is system noise, and “w _k ” is observation noise. The system noise v _k and the observation noise w _k are noises that follow a multidimensional normal distribution. System noise is also called process noise.

  FIG. 4 is a diagram illustrating an example of the SOC-OCV characteristic of the secondary battery 5. In FIG. 4, the horizontal axis represents SOC (%), and the vertical axis represents OCV (V). The charging state estimation unit 21 temporarily estimates the SOC value based on the OCV value estimated using the system model and the SOC-OCV characteristic shown in FIG. The charging state estimation unit 21 corrects the provisionally estimated SOC value with a Kalman filter based on an observation error that is a difference between the estimated value of the both-end voltage u estimated using the system model and the voltage observation value u, and corrects it. The SOC value is actually estimated by using the SOC value as the estimated value of the SOC.

  Hereinafter, the SOC estimation calculation performed by the charge state estimation unit 21 will be described in more detail, including processing when the use of the secondary battery 5 is resumed after the use of the secondary battery 5 is stopped. In the following description, the discretized time index “k” is written in parentheses instead of subscripts.

[2.1. Configuration of charge state estimation unit 21]
FIG. 5 is a functional block diagram of the charge state estimation unit 21. As illustrated in FIG. 5, the charging state estimation unit 21 includes a storage unit 40, an A / D conversion unit 41 (an example of an observation value acquisition unit), a calculation unit 42, a determination unit 43, and an initial value setting unit 44. With. The calculation unit 42 includes a battery state estimation unit 50, a gain setting unit 51, and a filter unit 52. The gain setting unit 51 and the filter unit 52 function as a Kalman filter.

  The charge state estimation unit 21 is a microcomputer including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, an A / D conversion unit, an input / output port, and the like. The microcomputer CPU functions as the calculation unit 42, the determination unit 43, and the initial value setting unit 44 by reading and executing a program stored in the ROM or flash memory. The storage unit 40 is configured by a RAM or the like.

  Note that all or part of the calculation unit 42, the determination unit 43, and the initial value setting unit 44 can be configured by hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). In addition, the above-described program can be read from a recording disk (for example, CD or DVD) by a reading unit (not shown) and stored in a ROM or flash memory.

  The storage unit 40 stores various parameters of the equivalent circuit model 30 used by the charging state estimation unit 21, various parameters of the Kalman filter, information indicating SOC-OCV characteristics, and the like. In addition, the storage unit 40 stores an SOC value that is the latest result of the estimation calculation performed by the charge state estimation unit 21.

  The A / D converter 41 repeatedly digitally converts the voltage observation value u output from the voltage sensor 11 every predetermined time, and outputs the result as the voltage observation value u (k). The A / D conversion unit 41 repeatedly digitally converts the current observation value i output from the current sensor 12 every predetermined time, and outputs the result as the current observation value i (k).

  The battery state estimation unit 50 acquires the voltage observation value u (k) and the current observation value i (k) from the A / D conversion unit 41. Further, the battery state estimation unit 50 acquires the post-condition estimation value x ^ (k−1) and various parameters of the equivalent circuit model 30 from the storage unit 40.

The a posteriori state estimated value x ^ (k-1) is a state vector of the secondary battery 5 that is estimated by the charge state estimating unit 21 at time k1-1. Here, state estimation value x (k), which is a state vector of secondary battery 5 at time k, is expressed by the following equation (9), and includes SOC value SOC (k), voltage u1 (k), and voltage u2 ( k).

The battery state estimation unit 50 determines the prior state estimated value x ^-(k) based on the posterior state estimated value x ^ (k-1), the voltage observed value u (k), and the current observed value i (k). Is calculated. For example, the battery state estimation unit 50 can obtain the prior state estimated value x ^-(k) by performing the calculation of the following equation (10) corresponding to the above equation (5). Further, the current observation value i (k) is an integrated value of the current i flowing through the secondary battery 5 in a predetermined period as shown in the following formula (11), and the predetermined period is, for example, 1 second.

  In the above equation (10), f (x ^ (k-1), i (k)) is the post-state state estimated value x ^ (k-1), the current observation value i (k), and the prior state estimated value. It is a function indicating the relationship with x ^-(k). In the above formula (10), the current observation value i (k) is used, but the current observation value i (k−1) may be used.

Further, the battery state estimation unit 50 estimates the voltage estimated value u which is an estimated value of the both-ends voltage u of the secondary battery 5 based on the observed current value i (k) and the prior state estimated value x ^-(k). ^ (K) is calculated. For example, the battery state estimation unit 50 can obtain the estimated voltage value u ^ (k) by performing the calculation of the following formula (12) corresponding to the above formula (6). The battery state estimation unit 50 outputs the prior state estimation value x ^-(k) to the filter unit 52.

Further, the battery state estimation unit 50 calculates a difference u˜ (k) between the voltage observation value u (k) and the voltage estimation value u ^ (k). For example, the battery state estimation unit 50 can obtain the difference u˜ (k) by performing the calculation of the following equation (13). The battery state estimation unit 50 outputs the difference u˜ (k) to the gain setting unit 51.

Gain setting unit 51 obtains from the battery state estimating unit 50 the difference u ~ a (k), to obtain the observation noise sigma _w and system noise sigma _v from the storage unit 40. Calculating the gain setting unit 51, the difference u ~ and (k), and the posterior error covariance matrix P (k-1), and the observation noise sigma _w, based on the system noise sigma _v, Kalman gain G (k) is To do. Note that the observation noise Σ _w is the covariance of the observation noise w _k described above, and the system noise Σ _v is the covariance of the system noise v _k described above.

The gain setting unit 51 obtains the prior error covariance matrix P- (k) at time k by, for example, the calculation of the following equation (14). In the following formula (14), “A” can be, for example, the Jacobian of f (x ^ (k−1), i (k)) in the above formula (10). For example, the gain setting unit 51 can obtain the Jacobian “A” by the calculation of the following equation (15) based on the a posteriori state estimated value x ^ (k−1) at the time k−1.

Next, the gain setting unit 51, based on a pre-error covariance matrix P- (k) and system noise sigma _v at time k, to calculate the Kalman gain G (k). For example, the gain setting unit 51 can obtain the Kalman gain G (k) by the calculation of the following equation (16).

Further, the gain setting unit 51 calculates the posterior error covariance matrix P (k) at time k based on the prior state estimated value x ^-(k), the Kalman gain G (k), and the difference u ~ (k). Calculate. For example, the gain setting unit 51 can obtain the posterior error covariance matrix P (k) by the calculation of the following equation (17).

The filter unit 52 calculates the posterior state estimated value x ^ (k) based on the prior state estimated value x ^-(k) and the Kalman gain G (k). Specifically, the filter unit 52 corrects the prior state estimated value x ^-(k) based on the Kalman gain G (k) and the difference u ~ (k). ) Is calculated. For example, the filter unit 52 can obtain the correction values x to (k) by the calculation of the following equation (18).

The filter unit 52 calculates the posterior state estimated value x ^ (k) based on the prior state estimated value x ^-(k) and the corrected values x ~ (k). For example, the filter unit 52 can obtain the posterior state estimated value x ^ (k) by the calculation of the following equation (19).

Then, the filter unit 52 extracts the posterior state estimated value SOC ^ (k) of the SOC included in the posterior state estimated value x ^ (k). For example, the filter unit 52 can obtain the posterior state estimated value SOC ^ (k) by the calculation of the following equation (20).

  The filter unit 52 stores the extracted posterior state estimated value x ^ (k) in the storage unit 40 and outputs the calculated posterior state estimated value SOC ^ (k) to the vehicle control device 2. It should be noted that the posterior state estimated value SOC ^ (k) included in the posterior state estimated value x ^ (k) stored in the storage unit 40 immediately before the stop timing when the use of the secondary battery 5 is stopped is the SOC previous final value. It is.

  The calculation method of the posterior state estimated value SOC ^ (k) is not limited to the above-described example. The calculation method of the posterior state estimated value SOC ^ (k) only needs to be able to calculate the posterior state estimated value SOC ^ (k) by the estimation calculation using the equivalent circuit model. For example, the charging state estimation unit 21 can also calculate the posterior state estimated value SOC ^ (k) by a known estimation process.

[2.2. Initial value SOC (0) setting process]
As described above, the charging state estimation unit 21 includes the storage unit 40, the determination unit 43, and the initial value setting unit 44. The determination unit 43 determines whether or not the use of the secondary battery 5 has been resumed after the set time T1 has elapsed since the use of the secondary battery 5 was stopped.

  Further, the determination unit 43 determines whether or not the last SOC last value (second initial value) stored in the storage unit 40 is valid. The last SOC last value is the posterior state estimated value SOC ^ (k) last stored in the storage unit 40 before the stop timing.

  The initial value setting unit 44 determines the initial value SOC (0) of the SOC value used by the battery state estimation unit 50 after the use of the secondary battery 5 is resumed based on the determination result by the determination unit 43. The determined initial value SOC (0) is set in the battery state estimation unit 50. The initial value SOC (0) is a value set as SOC ^ (k-1) in the posterior state estimated value x ^ (k-1) at time k-1 when the time at which the estimation calculation is resumed is time k. It is. Thereby, the battery state estimation part 50 can calculate prior state estimated value x ^-(k), for example using the said Formula (10).

[2.2.1. Information stored in storage unit 40]
The memory | storage part 40 has memorize | stored the table or arithmetic expression which shows a SOC-OCV characteristic. FIG. 6 is a diagram illustrating an example of a table indicating SOC-OCV characteristics. The table indicating the SOC-OCV characteristic is a table in which the SOC value is associated with the OCV value for each OCV value. For example, the SOC value “78.0 (%) is associated with the OCV value“ 3.30 (V) ”. ) ".

  Further, the storage unit 40 stores charging time information and discharging time information. The charging time information is a table or an arithmetic expression showing the relationship between the first variation range AR1, which is a range of variation in SOC when the secondary battery 5 is charging, and the OCV value. The information at the time of discharge is a table or an arithmetic expression indicating the relationship between the second variation range AR2 that is the range of variation in SOC when the secondary battery 5 is in discharge and the OCV value.

  FIG. 7 is a diagram illustrating a relationship between the first variation range AR1 and the OCV value in the charging information. In the example illustrated in FIG. 7, for example, the first variation range AR1 “75.0 to 80.0 (%)” is associated with the OCV value “3.30 (V)” and the OCV value “3.29”. The first variation range AR1 “74.5-79.5 (%)” is associated with “(V)”.

  FIG. 8 is a diagram showing the relationship between the second variation range AR2 and the OCV value in the discharge time information. In the example illustrated in FIG. 8, for example, the OCV value “3.30 (V)” is associated with the second variation range AR2 “73.0-78.0 (%)”, and the OCV value “3.29”. The second variation range AR2 “72.5 to 77.5 (%)” is associated with “(V)”.

[2.2.2. Processing of determination unit 43]
The determination unit 43 illustrated in FIG. 5 determines whether or not the use of the secondary battery 5 has been resumed after the set time T1 has elapsed since the use of the secondary battery 5 was stopped. Specifically, the determination unit 43 counts a stop time Tx from when the use of the secondary battery 5 is stopped to when the stop is released.

  The determination unit 43 has a counter (not shown) that starts counting at the stop timing. The determination unit 43 can stop the count of the counter at the start timing when the stop of the use of the secondary battery 5 is released, and the count value of the counter can be set as the stop time Tx.

Note that the determination unit 43 determines that it is the stop timing, for example, when the ignition signal _SIGN changes from the state indicating the ignition ON to the state indicating the ignition OFF. Moreover, the determination part 43 determines with it being a starting timing, when the ignition signal _SIGN changes from the state which shows ignition OFF to the state which shows ignition ON.

  When the stop time Tx is less than the set time T1, the determination unit 43 determines that the use of the secondary battery 5 has been resumed before the set time T1 has elapsed since the use of the secondary battery 5 was stopped. Further, when the stop time Tx is equal to or longer than the set time T1, the determination unit 43 determines that the use of the secondary battery 5 has been resumed after the set time T1 has elapsed since the use of the secondary battery 5 was stopped. The set time T1 is set to a time required for depolarization of the secondary battery 5 (hereinafter referred to as polarization elimination time), and thus whether or not the polarization of the secondary battery 5 is eliminated. Can be determined.

  Further, the determination unit 43 determines whether or not the last SOC last value stored in the storage unit 40 is valid. The fact that the last SOC last value is valid means that the last SOC last value stored in the storage unit 40 can be used as the initial value SOC (0).

  The determination unit 43 determines that the SOC previous final value is valid, for example, when the SOC previous final value is within a normal range or when there is no data corruption in the SOC previous final value. The determination unit 43 determines that the SOC previous final value is not valid, for example, when the SOC previous final value is not within the normal range or when there is data corruption in the SOC previous final value.

[2.2.3. Processing of Initial Value Setting Unit 44]
The initial value setting unit 44 changes the initial value SOC (0) used when the use of the secondary battery 5 is resumed based on the determination result by the determination unit 43.

  Specifically, the initial value setting unit 44 changes the initial value SOC (0) when the stop time Tx is equal to or longer than the set time T1 and when the stop time Tx is less than the set time T1. Furthermore, when the stop time Tx is less than the set time T1, the initial value setting unit 44 changes the initial value SOC (0) based on whether or not the last SOC last value is valid.

  In addition, when the minimum value priority setting that prioritizes the minimum value among the plurality of SOC values obtained by different methods to be described later is valid, the initial value setting unit 44 can obtain a plurality of values obtained by different methods regardless of the stop time Tx. The lowest SOC value among the SOC values can be set as the initial value SOC (0). Each case will be specifically described below.

[2.2.3.1. When Tx ≧ T1]
Initial value setting unit 44 determines an SOC value to be set to initial value SOC (0) by the first method, and sets it in battery state estimating unit 50.

  Specifically, when the determination unit 43 determines that the stop time Tx is equal to or longer than the set time T1, the initial value setting unit 44 starts from the A / D conversion unit 41 after the use of the secondary battery 5 is resumed. Based on the output voltage observation value u (k), the SOC value to be set to the initial value SOC (0) is determined and set in the battery state estimation unit 50.

  Based on the information indicating the SOC-OCV characteristic stored in the storage unit 40, the initial value setting unit 44 sets the SOC value corresponding to the voltage observation value u (k) as the initial value SOC (0) to the battery state estimation unit 50. Set. For example, when the table shown in FIG. 6 is stored in the storage unit 40 and u (k) = 3.29 (V), the battery state is determined with the SOC value “77.5%” as the initial value SOC (0). Set in the estimation unit 50.

  When Tx ≧ T1, since the polarization elimination time of the secondary battery 5 has elapsed, the polarization voltage is not superimposed on the voltage observation value u (k). Therefore, the initial value SOC (0) can be appropriately set by extracting the SOC value corresponding to the voltage observation value u (k) from the information indicating the SOC-OCV characteristic.

  Immediately after the use of the secondary battery 5 is resumed, the power conversion unit 4 (see FIG. 1) is not operating, the current i flowing from the secondary battery 5 is small, and output from the A / D conversion unit 41. It is assumed that the observed voltage u (k) can be regarded as an OCV value, but is not limited to this example. For example, the initial value setting unit 44 determines the SOC value corresponding to the OCV value that matches the voltage observation value u (k) output from the A / D conversion unit 41 immediately before the start timing from the information indicating the SOC-OCV characteristic. It can also be extracted.

  In addition, the storage unit 40 can store information (a table or an arithmetic expression) indicating SOC-CCV (Closed Circuit Voltage) characteristics immediately after the use of the secondary battery 5 is resumed. The initial value setting unit 44 stores the SOC value corresponding to the CCV value that matches the voltage observation value u (k) output from the A / D conversion unit 41 immediately after the start timing, in the SOC-CCV stored in the storage unit 40. It can also be extracted from information indicating characteristics. The CCV value is a closed circuit voltage of the secondary battery 5.

[2.2.3.2. When Tx <T1 and the last SOC value is valid]
When the determination unit 43 determines that the stop time Tx is less than the set time T1 and the last SOC last value stored in the storage unit 40 is valid, the initial value setting unit 44 uses the second method. The SOC value to be set to the initial value SOC (0) is determined and set in the battery state estimation unit 50.

  Specifically, the initial value setting unit 44 sets the SOC last final value stored in the storage unit 40 to the battery state estimation unit 50 as the initial value SOC (0). As described above, the SOC last final value is the posterior state estimated value SOC ^ (k) stored in the storage unit 40 immediately before the stop timing.

  When Tx <T1, the polarization elimination time of the secondary battery 5 has not elapsed, and the polarization voltage is superimposed on the observed voltage u (k), but the superimposed polarization voltage is caused by charging. The voltage observation value u (k) cannot determine whether the polarization voltage is a polarization voltage due to discharge or the polarization voltage due to discharge.

  Therefore, when the SOC value corresponding to the voltage observation value u (k) is extracted from the information indicating the SOC-OCV characteristic and the initial value SOC (0) is set, the deviation between the initial value SOC (0) and the true value is different. There is a risk that the post-state state estimated value SOC ^ (k) converges slowly.

  Therefore, when Tx <T1 and the last SOC last value is valid, the initial value setting unit 44 sets the last SOC last value stored in the storage unit 40 as the initial value SOC (0). Since the last SOC final value is a value according to the polarization state of the secondary battery 5 immediately before the power supply system 1 is stopped, the deviation between the initial value SOC (0) and the true value can be suppressed. Therefore, the convergence of the posterior state estimated value SOC ^ (k) can be improved, and the estimation accuracy of the SOC value can be improved.

[2.2.3.3. When Tx <T1 and the last SOC last value is not valid]
The initial value setting unit 44 uses the third method when the determination unit 43 determines that the stop time Tx is less than the set time T1 and that the last SOC last value stored in the storage unit 40 is not valid. The SOC value to be set to the initial value SOC (0) is determined and set in the battery state estimation unit 50. Specifically, the initial value setting unit 44 sets the SOC value corresponding to the voltage observation value u (k) as the initial value SOC (0) based on the charging time information and discharging time information stored in the storage unit 40. It is determined and set in the battery state estimation unit 50.

  For example, the initial value setting unit 44 sets the median value CV in the overlapping range AR3 of the first variation range AR1 and the second variation range AR2 associated with the OCV value that matches the voltage observation value u (k) to the initial value. It can be determined as SOC (0). Here, the charging time information stored in the storage unit 40 is in the state shown in FIG. 7, the discharging time information stored in the storage unit 40 is in the state shown in FIG. 8, and the voltage observation value u (k) is “ 3.29 (V) ”.

  In this case, the first variation range AR1 associated with the OCV value that matches the voltage observation value u (k) is “74.5-79.5 (%)”, and the voltage observation value u (k) The second variation range AR2 associated with the matching OCV value is “72.5 to 77.5 (%)”. Therefore, the overlapping range AR3 is “74.5-77.5 (%)”, and the median value CV of the overlapping range AR3 is “76.0 (%)”. Therefore, initial value setting unit 44 determines “76.0 (%)” as initial value SOC (0).

  As described above, when Tx <T1, the polarization elimination time of the secondary battery 5 has not elapsed, and the polarization voltage is superimposed on the voltage observation value u (k). Whether the voltage is a polarization voltage caused by charging or a polarization voltage caused by discharging cannot be determined from the voltage observation value u (k).

  Therefore, when Tx <T1 and the last SOC last value is not valid, the initial value setting unit 44 determines the median value CV of the overlapping range AR3 of the SOC value variation range AR1 during charging and the SOC value variation range AR2 during discharging. Is determined as the initial value SOC (0). Since the initial value SOC (0) is determined from the range of the overlapping range AR3, the initial value SOC (0) greatly deviates from the true value regardless of whether the polarization is caused by charging or discharging. Can be suppressed. Therefore, the convergence of the posterior state estimated value SOC ^ (k) can be improved, and the estimation accuracy of the SOC value can be improved.

  The storage unit 40 can also store the median value CV corresponding to the OCV value in association with the OCV value for each magnitude of the OCV value. In this case, the initial value setting unit 44 can acquire the median value CV corresponding to the OCV value that matches the observed voltage value u (k) from the storage unit 40.

  In addition, the storage unit 40 uses the median value CV1 of the first variation range AR1 corresponding to the OCV value and the median value CV2 of the second variation range AR2 corresponding to the voltage observation value u (k) as the OCV value. It can also be stored in association with the OCV value. In this case, the initial value setting unit 44 may determine the average value Vav of the median value CV1 and the median value CV2 associated with the OCV value that matches the observed voltage value u (k) as the initial value SOC (0). it can.

  The storage unit 40 can also store the average value Vav corresponding to the OCV value in association with the OCV value for each size of the OCV value. In this case, the initial value setting unit 44 can acquire the average value Vav associated with the OCV value that matches the voltage observation value u (k) from the storage unit 40.

  Moreover, the memory | storage part 40 can memorize | store the charging / discharging information which shows whether it is the state in which the secondary battery 5 is charged or discharged just before a stop timing. Based on the charge / discharge information stored in the storage unit 40, the initial value setting unit 44 can determine whether the secondary battery 5 has been charged or discharged immediately before the stop timing. .

  If the secondary battery 5 is in a state of being charged immediately before the stop timing, the initial value setting unit 44 can determine the center value of the first variation range AR1 as the initial value SOC (0). In addition, when the secondary battery 5 is in a state of being discharged immediately before the stop timing, the initial value setting unit 44 can determine the center value of the second variation range AR2 as the initial value SOC (0). it can.

[2.2.3.4. When minimum value priority setting is enabled]
When the minimum value priority setting is valid, the initial value setting unit 44 determines the smallest SOC value among the plurality of SOC values obtained by the first to third methods described above as the initial value SOC (0). The battery state estimation unit 50 is set.

  The initial value setting unit 44 determines that the minimum value priority setting is not valid when the minimum value priority setting flag (not shown) stored in the storage unit 40 is set to “0”, and the minimum value priority setting flag is If it is set to “1”, it is determined that the minimum value priority setting is valid.

  When the minimum value priority setting is valid, the initial value setting unit 44 performs processing for obtaining a plurality of SOC values by the above-described first to third methods, and selects the smallest SOC value among the plurality of SOC values. The initial value SOC (0) is determined and set in the battery state estimation unit 50.

  In the estimation calculation using the Kalman filter, the convergence of the posterior state estimated value SOC ^ (k) is higher when the initial value SOC (0) is smaller than when the initial value SOC (0) is larger than the true value. Therefore, by setting the smallest SOC value among the plurality of SOC values obtained by different methods as the initial value SOC (0), the convergence of the posterior state estimated value SOC ^ (k) can be improved. The accuracy of value estimation can be improved.

  If the determination unit 43 determines that the last SOC last value stored in the storage unit 40 is not valid, the last SOC last value obtained by the second method may not be used. Thereby, it can prevent that the estimation precision of a SOC value falls.

  Moreover, even if it is a case where the determination part 43 determines that the last SOC last value stored in the storage unit 40 is valid, the initial value setting unit 44 is the second of the first to third methods described above. Among the plurality of SOC values obtained by the two methods, the smallest SOC value can be determined as the initial value SOC (0) and set in the battery state estimation unit 50.

  Further, even when the minimum value priority setting is valid, the initial value setting unit 44 sets the smallest SOC value among the plurality of SOC values described above as the initial value SOC ( 0). Further, even when the minimum value priority setting is valid, the initial value setting unit 44 sets the smallest SOC value among the plurality of SOC values described above as the initial value SOC (only when Tx <T1). 0) can also be determined.

  In the above-described example, the calculation unit 42, the determination unit 43, and the initial value setting unit 44 have been described separately. However, the calculation unit 42 has functions of the determination unit 43 and the initial value setting unit 44. You can also. That is, the calculation unit 42 can execute the above-described processing by the determination unit 43 and the initial value setting unit 44.

  In the above-described example, the SOC previous final value is used as the second initial value. However, the second initial value is the post-state state estimated value SOC ^ (k stored in the storage unit 40 immediately before the stop timing. ) May be the post-state estimated value SOC ^ (k−n) stored in the storage unit 40 before n (n is a natural number) steps.

  The initial value setting unit 44 can also set the posterior state estimated value SOC ^ (k−n) as the initial value SOC (0) when the last SOC last value is not valid.

  Also, the initial value setting unit 44 stores the initial value u1 (0) of the voltage u1 and the initial value u2 (0) of the voltage u2 in the storage unit 40 before the stop timing, as in the case of the initial value SOC (0). It can be set based on the stored posterior state estimated value SOC ^ (k). For example, the initial value setting unit 44 includes the posterior state estimated value u1 ^ (k) and the posterior state estimated value u2 ^ () included in the posterior state estimated value x ^ (k) stored in the storage unit 40 before the stop timing. k) can be an initial value u1 (0) and an initial value u2 (0).

[3. Processing by the charge state estimation unit 21]
Next, an example of a flow of processing executed by the charging state estimation unit 21 which is an example of an estimation device will be described using a flowchart. FIG. 9 is a flowchart illustrating an example of a processing procedure executed by the charge state estimation unit 21, and is a process that is repeatedly executed.

  As shown in FIG. 9, the determination part 43 of the charge condition estimation part 21 determines whether an ignition is ON (step S10). When it is determined that the ignition is ON (step S10; Yes), the determination unit 43 determines whether the ignition is immediately after being turned on from OFF (step S11). When the determination unit 43 determines that the ignition is immediately after the ignition switch is turned on from OFF (step S11: Yes), the initial value setting unit 44 of the charge state estimation unit 21 performs a process for determining the initial value SOC (0). It performs (step S12).

  Next, the initial value setting unit 44 of the charging state estimation unit 21 sets the initial value SOC (0) determined in step S12 in the calculation unit 42 of the charging state estimation unit 21 (step S13). When step S13 is completed, the calculation unit 42 of the charge state estimation unit 21 determines the SOC value when the determination unit 43 determines that it is not immediately after the ignition is switched from OFF to ON (step S10: No). Execute (Step S14). The calculation unit 42 includes the initial value SOC (0) when the determination unit 43 determines that step S13 is completed and immediately after the ignition is switched from OFF to ON (step S11: Yes). Based on the initial value x ^ (0), the observed voltage value u (k), and the observed current value i (k), the SOC value is estimated. In addition, when the determination unit 43 determines that the ignition is not immediately after the ignition is switched from OFF to ON (step S11: No), the calculation unit 42 determines the posterior state estimated value x ^ (k-1) and the voltage observation value u. Based on (k) and the current observation value i (k), the SOC value estimation calculation is executed.

  Calculation unit 42 outputs a posteriori state estimated value SOC ^ (k), which is the result of the estimation calculation, to vehicle control device 2 (step S15). Further, the calculation unit 42 stores the posterior state estimated value SOC ^ (k), which is the result of the estimation calculation, in the storage unit 40 (step S16).

  If the determination unit 43 determines that the ignition is not turned on (step S10: No), the charging state estimation unit 21 counts the stop time Tx (step S17). When the process of step S15 or the process of step S17 ends, the process shown in FIG. 9 ends.

  FIG. 10 is a flowchart showing an example of the process of step S11 of FIG. As shown in FIG. 10, the determination unit 43 of the charge state estimation unit 21 determines whether or not the minimum value priority setting is valid (step S20).

  When determining that the minimum value priority setting is not valid (step S20: No), the determination unit 43 determines whether or not the stop time Tx is equal to or longer than the set time T1 (step S21). When the determination unit 43 determines that the stop time Tx is equal to or longer than the set time T1 (step S21: Yes), the initial value setting unit 44 of the charge state estimation unit 21 is based on the voltage observation value u (k). An initial value SOC (0) is determined from the SOC-OCV characteristic (step S22).

  If the determination unit 43 determines that the stop time Tx is not equal to or longer than the set time T1 (step S21: No), the determination unit 43 determines whether or not the last SOC last value stored in the storage unit 40 is valid (step S23). If the determination unit 43 determines that the last SOC last value is valid (step S23: Yes), the initial value setting unit 44 sets the last SOC last value stored in the storage unit 40 to the initial value SOC (0). Determine (step S24).

  When it is determined by the determination unit 43 that the last SOC last value is not valid (step S23: No), the initial value setting unit 44 is charged and discharged from the voltage observation value u (k) that is a voltage observation value. The median value CV of the overlapping range AR3 of the SOC value variation ranges AR1 and AR2 is determined as the initial value SOC (0) (step S25).

  In step S20, when the determination unit 43 determines that the minimum value priority setting is valid (step S20: Yes), the initial value setting unit 44 executes the processes of steps S26 to S29. The initial value setting unit 44 determines the smallest SOC value among the values acquired in the processes of steps S26 to S29 as the initial value SOC (0) (step S29). The process of step S26 is the same as the process of step S22, the process of step S27 is the same as the process of step S24, and the process of step S28 is the same as the process of step S25.

  As described above, the charging state estimation unit 21 (an example of the estimation device) according to the embodiment includes the A / D conversion unit 41 (an example of the observation value acquisition unit), the calculation unit 42, and the storage unit 40. The A / D conversion unit 41 acquires voltage observation values u (k) and i (k) (an example of observation values of the voltage u and current i of the secondary battery 5). The calculation unit 42 performs the estimation calculation using the equivalent circuit model 30 of the secondary battery 5 on the basis of the voltage observation values u (k) and i (k) acquired by the A / D conversion unit 41. Posterior state estimated value SOC ^ (k) (an example of the SOC value) indicating the state of charge is estimated. The storage unit 40 stores the posterior state estimated value SOC ^ (k) estimated by the calculation unit 42. When the stop time Tx from when the use of the secondary battery 5 is stopped to when the stop is released is equal to or longer than the set time T1 (an example of a preset time), the calculation unit 42 determines the voltage observation value u (k ) Is used as the initial value SOC (0) (an example of the initial value of the SOC value in the estimation calculation), and when the stop time Tx is less than the set time T1, the secondary battery 5 The estimation calculation is started with a value determined according to whether or not the last SOC last value (an example of the previous SOC value) stored in the storage unit 40 before the use is stopped as an initial value SOC (0). Thereby, even when the polarization voltage is superimposed on the voltage of the secondary battery 5 at the time of starting the power supply system 1, it is possible to suppress a decrease in the estimation accuracy of the SOC value, and the SOC last value is valid. Since the value determined according to whether or not is the initial value SOC (0), the estimation accuracy of the SOC value can be improved.

  In addition, when the stop time Tx is less than the set time T1, the calculation unit 42 sets the SOC previous final value as the initial value SOC (0) and the SOC previous final value must be valid if the SOC previous final value is valid. For example, a value determined based on the observed voltage value u (k) is set as an initial value SOC (0). Thereby, the estimation accuracy of the SOC value can be improved as compared with the case where the last SOC last value that is not valid is used as the SOC initial value.

  In addition, the storage unit 40 is charging time information (an example of first information) indicating a relationship between the voltage (OCV value or CCV value) of the secondary battery 5 and the SOC value when the secondary battery 5 is charging. And discharge time information (an example of second information) indicating the relationship between the voltage (OCV or CCV) of the secondary battery 5 and the SOC value when the secondary battery 5 is being discharged. When the stop time Tx is less than the set time T1, the calculation unit 42 determines the SOC previous final value as the initial value SOC (0) if the SOC previous final value is valid, and the SOC previous final value must be valid. For example, the initial value SOC (0) is determined based on the charging time information and the discharging time information. Thereby, since the value using both the charging time information and the discharging time information is set as the initial value SOC (0), it is possible to suppress the initial value SOC (0) from greatly deviating from the true value. Therefore, the convergence of the posterior state estimated value SOC ^ (k) can be improved, and the estimation accuracy of the SOC value can be improved.

  Further, the charging time information includes the relationship between the voltage (OCV value or CCV value) of the secondary battery 5 when the secondary battery 5 is being charged and the first variation range AR1 that is the variation range of the SOC value. Contains information to indicate. In the discharge time information, information indicating the relationship between the voltage (OCV value or CCV value) of the secondary battery 5 when the secondary battery 5 is in discharge and the second variation range AR2 that is the variation range of the SOC value. Is included. If the last SOC last value is not valid, the calculation unit 42 sets the median value CV in the overlapping range AR3 of the first variation range AR1 and the second variation range AR2 corresponding to the voltage observation value u (k) to the initial value. An estimation calculation is performed as SOC (0). Thereby, it is possible to more accurately suppress the initial value SOC (0) from deviating greatly from the true value, and it is possible to improve the convergence of the posterior state estimated value SOC ^ (k) and improve the estimation accuracy of the SOC value.

  Further, when the minimum value priority setting that prioritizes the minimum value among a plurality of SOC values obtained by different methods is valid, the calculation unit 42 initially sets the smallest SOC value among the plurality of SOC values obtained by different methods. An estimation calculation is performed as the value SOC (0). Thereby, the convergence of the posterior state estimated value SOC ^ (k) can be improved, and the estimation accuracy of the SOC value can be improved.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Power supply system 2 Vehicle control apparatus 3 Motor 4 Power conversion part 5 Secondary battery 6 Battery monitoring system 7 Relay 10 Battery state monitoring part 11 Voltage sensor 12 Current sensor 20 Switch control part 21 Charging state estimation part (an example of an estimation apparatus)
30 equivalent circuit model 40 storage unit 41 A / D conversion unit (an example of an observation value acquisition unit)
42 calculation unit 43 determination unit 44 initial value setting unit 50 battery state estimation unit 51 gain setting unit 52 filter unit 100 vehicle mounting system

Claims (7)

An observation value acquisition unit for acquiring observation values of the voltage and current of the secondary battery;
Based on the observation value acquired by the observation value acquisition unit, an estimation unit that estimates an SOC value indicating the state of charge of the secondary battery by an estimation calculation using an equivalent circuit model of the secondary battery;
A storage unit that stores the SOC value estimated by the calculation unit,
The computing unit is
When the stop time from when the use of the secondary battery is stopped to when the stop is released is equal to or longer than a preset time, a value determined based on the observed value of the voltage is set as the SOC in the estimation calculation. When the estimation calculation is started as an initial value of the value and the stop time is less than the preset time, the previous SOC value stored in the storage unit before the use of the secondary battery is stopped An estimation apparatus, wherein the estimation calculation is started with a value determined according to whether or not the SOC value is valid as the initial value. The computing unit is
When the stop time is less than the preset time, if the previous SOC value is valid, the previous SOC value is set as the initial value, and if the previous SOC value is not valid, the observed value of the voltage The estimation apparatus according to claim 1, wherein a value determined based on the initial value is used as the initial value. The storage unit
First information indicating the relationship between the voltage of the secondary battery and the SOC value when the secondary battery is being charged, and the voltage of the secondary battery when the secondary battery is being discharged Storing second information indicating a relationship with the SOC value;
The computing unit is
When the stop time is less than the preset time, if the previous SOC value is valid, the previous SOC value is determined as the initial value, and if the previous SOC value is not valid, the first SOC value is determined. The estimation apparatus according to claim 2, wherein the initial value is determined based on the information and the second information. The first information includes
Information indicating the relationship between the voltage of the secondary battery and the first variation range that is the variation range of the SOC value when the secondary battery is being charged is included,
The second information includes
Information indicating the relationship between the voltage of the secondary battery and the second variation range that is the variation range of the SOC value when the secondary battery is in discharge is included,
The computing unit is
If the previous SOC value is not valid, the estimation calculation is performed using the median value in the overlapping range of the first variation range and the second variation range corresponding to the observed value of the voltage as the initial value. The estimation apparatus according to claim 3, wherein the estimation apparatus is characterized in that: The computing unit is
When the minimum value priority setting that prioritizes the minimum value among a plurality of SOC values obtained by different methods is valid, the estimation calculation is performed using the smallest SOC value among the plurality of SOC values obtained by the different methods as the initial value. The estimation device according to any one of claims 1 to 4, wherein: An observation value acquisition step of acquiring observation values of the voltage and current of the secondary battery;
Based on the observation value acquired in the observation value acquisition step, a calculation step of estimating an SOC value indicating a charging state of the secondary battery by an estimation calculation using an equivalent circuit model of the secondary battery;
A storage step of storing the SOC value estimated by the calculation step in a storage unit,
The calculation step includes
When the stop time from when the use of the secondary battery is stopped to when the stop is released is equal to or longer than a preset time, a value determined based on the observed value of the voltage is set as the SOC in the estimation calculation. When the estimation calculation is started as an initial value of the value and the stop time is less than the preset time, the previous SOC value stored in the storage unit before the use of the secondary battery is stopped An estimation method characterized by starting the estimation calculation using a value determined according to whether or not the SOC value is valid as the initial value. Observation value acquisition procedure for acquiring observation values of voltage and current of the secondary battery,
A calculation procedure for estimating an SOC value indicating a charge state of the secondary battery by an estimation calculation using an equivalent circuit model of the secondary battery based on the observation value acquired in the observation value acquisition procedure;
A storage procedure for storing the SOC value estimated by the calculation procedure in a storage unit;
The calculation procedure is as follows:
When the stop time from when the use of the secondary battery is stopped to when the stop is released is equal to or longer than a preset time, a value determined based on the observed value of the voltage is set as the SOC in the estimation calculation. When the estimation calculation is started as an initial value of the value and the stop time is less than the preset time, the previous SOC value stored in the storage unit before the use of the secondary battery is stopped An estimation program that starts the estimation calculation using a value determined according to whether or not an SOC value is valid as the initial value.

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