JP7000030B2 - Estimator, estimation method, and estimation program - Google Patents

Description

The disclosed embodiments relate to an estimation device, an estimation method, and an estimation program.

Conventionally, electric vehicles such as hybrid vehicles and electric vehicles are equipped with a power source that supplies power to a motor that is a power source, and as such power source, power is supplied to the motor by discharge and generated by the motor. A rechargeable secondary battery that stores regenerative power is used.

Electric vehicles are generally equipped with an estimation device for estimating an SOC (State Of Charge) value so that electric power from a secondary battery can be stably supplied to a motor. The SOC value is a value indicating the state of charge of the secondary battery, and 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. There is.

By the way, in a secondary battery, polarization is generated internally by charging and discharging, and it may take a long time such as several tens of minutes to several tens of hours until the polarization is eliminated and stabilized. Therefore, even during the period when charging / discharging is not performed, the polarization voltage may be superimposed on the voltage of the secondary battery, which may reduce the estimation accuracy of the SOC value. Therefore, in an estimation device for estimating an SOC value, a technique has been proposed in which the SOC initial value is changed according to the length of the stop time of the power supply system until the power supply system including the secondary battery is started.

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

Specifically, the estimation device stores the SOC value estimated last time in the storage unit, and before the second stop period, in which the stop time of the power supply system is shorter than the first stop period, elapses. In this case, the SOC value stored in the storage unit is used as the SOC initial value. Further, when the stop time of the power supply system has passed the second stop period and before the first stop time has elapsed, the estimation device is based on the voltage of the secondary battery observed when the power supply system is stopped. Obtain the SOC initial value.

Japanese Unexamined Patent Publication No. 2008-145349

However, in the estimation device described in Patent Document 1, when the stop time of the power supply system is started before the second stop period elapses, the SOC value stored in the storage unit is not effective due to data corruption or the like. If this is the case, the initial SOC value becomes undefined, and the estimation accuracy of the SOC value may decrease.

One aspect of the embodiment is made in view of the above, and an object thereof is to provide an estimation device, an estimation method, and an estimation program capable of improving the estimation accuracy of the SOC value.

The estimation device according to one embodiment includes an observation value acquisition unit, a calculation unit, a storage unit, and a determination unit. The observed value acquisition unit acquires the observed values of the voltage and the current of the secondary battery. The calculation unit estimates the SOC value indicating the charge state of the secondary battery by an estimation calculation using the 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. The determination unit determines the previous SOC when the previous SOC value, which is the SOC value stored in the storage unit before the use of the secondary battery is stopped, is not within the normal range or the data is corrupted. Determine that the value is not valid. When the stop time from the stop of use of the secondary battery to the release of the stop is equal to or longer than a preset time, the calculation unit sets a value determined based on the observed value of the voltage. When the estimation calculation is started by the first method of setting the initial value of the SOC value in the estimation calculation and the stop time is less than the preset time, if the previous SOC value is valid, the previous time. The second method using the SOC value as the initial value, and the third method using the value determined based on the observed value of the voltage as the initial value if the previous SOC value is not valid, respectively. Start the estimation operation. The storage unit further includes first information indicating the relationship between the open circuit voltage of the secondary battery and the SOC value when the secondary battery is being charged, and when the secondary battery is being discharged. The second information indicating the relationship between the open circuit voltage of the secondary battery and the SOC value is stored. Further, when the stop time is less than the preset time, the arithmetic unit further obtains the first information and the second information as the third method if the previous SOC value is not valid. Based on this, the initial value is determined.

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

FIG. 1 is a diagram showing 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 showing an example of an equivalent circuit model of a secondary battery. FIG. 4 is a diagram showing an example of SOC-OCV characteristics of a secondary battery. FIG. 5 is a functional block diagram of the charge state estimation unit. FIG. 6 is a diagram showing an example of a table showing SOC-OCV characteristics. FIG. 7 is a diagram showing the relationship between the first variation range in the charging information and the OCV value. FIG. 8 is a diagram showing the relationship between the second variation range in the discharge information and the OCV value. FIG. 9 is a flowchart showing 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 the estimation device, estimation method, and estimation program disclosed in the present application will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments shown below. Further, 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 such an example. For example, a power supply system including an estimation device can be applied in addition to the vehicle-mounted system, such as a power generation system that converts natural energy such as solar power and wind power into electric power.

[1. Vehicle mounting system configuration]
FIG. 1 is a diagram showing 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 electric vehicle (HEV) and an electric vehicle (EV) (not shown), for example.

The vehicle mounting 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 controls the motor 3 by starting the power supply system 1, connecting the power supply system 1 and the power conversion unit 4, and driving the power conversion unit 4.

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

The vehicle control device 2 can control the charge / discharge of the secondary battery 5 based on the SOC (State Of Charge) value indicating the state of the secondary battery 5, which will be described later, notified from the power supply system 1. For example, the vehicle control device 2 can increase the SOC value by supplying the regenerative power of the motor 3 to the power supply system 1 when the SOC value decreases. The SOC value is the charge rate (%) of the secondary battery 5, but may be the residual 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, a nickel hydrogen secondary battery, or the like. 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 comprises 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 puts 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 the 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 each 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 block monitoring units (not shown) provided for each of a plurality of battery blocks constituting the secondary battery 5, and each block monitoring unit has an abnormality in the corresponding battery block or the like. Can be detected.

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

The battery condition 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 the ignition signal _SIGN indicating the state of the ignition switch.

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

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 while the relay 7 is ON, the switch control unit 20 can turn off the relay 7 and put the power supply system 1 in the stopped state.

When the power supply system 1 is in the operating state, the charge state estimation unit 21 performs an estimation calculation for estimating the SOC value of the secondary battery 5. For example, the charge state estimation unit 21 uses the equivalent circuit model of the secondary battery 5 to determine the charge state 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. Performs an estimation operation to estimate the indicated SOC value. The charge state estimation unit 21 stops the SOC value estimation calculation 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 each time the estimation calculation is performed. Further, the charge 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 internally polarized by charging and discharging, and it takes time for the polarization to be eliminated and stabilized. Therefore, even during the period when charging / discharging is not performed, the polarization voltage may be superimposed on the voltage of the secondary battery 5, and the estimation accuracy of the SOC value may decrease.

Therefore, the charge state estimation unit 21 waits after a preset time T1 (hereinafter, may be referred to as a set time T1) elapses after the power supply system 1 is stopped and the use of the secondary battery 5 is stopped. It is determined whether or not the power supply system 1 is activated and the use of the secondary battery 5 is resumed. Based on the determination result, the charge state estimation unit 21 changes the initial value of the SOC (hereinafter referred to as the SOC initial value) used in the calculation of the SOC value estimation. The set time T1 is longer than the time required to eliminate the polarization of 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 the 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 of.

As shown in FIG. 2, the charge state estimation unit 21 starts the power supply system 1 after the set time T1 elapses from the stop timing (time t10) and the polarization disappears (time t11), and the secondary battery 5 When the timing for resuming the use (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 the observed voltage u acquired from the voltage sensor 11 by the SOC-OCV (Open Circuit Voltage) characteristic or the like. The 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 the value of the OCV is hereinafter referred to as the OCV value.

Further, when the start timing occurs before the set time T1 elapses 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 to perform the SOC. Performs an estimation operation of.

The second initial value is the SOC value estimated and calculated before the stop timing, for example, the SOC value calculated by the last estimation operation immediately before the stop timing. Hereinafter, the second initial value may be described as the SOC previous final value. The third initial value is, for example, a value determined from the voltage observed value u acquired from the voltage sensor 11 based on the SOC-OCV characteristics and the like.

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 the second initial value has data corruption.

When the charging state estimation unit 21 determines 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 determines that the second initial value is not valid. The estimation operation is performed with the third initial value as the SOC initial value.

As described above, when the charge state estimation unit 21 resumes the use of the secondary battery 5 before the set time T1 elapses after the use of the secondary battery 5 is stopped, the last final value of the SOC is valid. The SOC initial value is changed depending on whether or not it is. Therefore, when the SOC previous final value is not valid, the estimation accuracy of the SOC value can be improved as compared with the case where the SOC previous final 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 the equivalent circuit model that models the secondary battery 5.

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

The resistance element 32 is a resistance element having a resistance value R0, and the voltage u0 of the resistance element 32 increases in direct proportion to a 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 changes 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 changes the current i flowing through the secondary battery 5. On the other hand, it changes transiently.

The voltage u across 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 equation (1).

The voltage u0 can be expressed as shown in the following equation (2) from the current i flowing through the secondary battery 5 and the resistance value R0. Further, the differential equations of 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 equations (3) and (4).

The charge state estimation unit 21 estimates the SOC value by an estimation calculation using the above-mentioned equivalent circuit model 30. The following equations (5) and (6) show a system model representing the state of the secondary battery 5. Equation (5) is a state equation showing the state of the secondary battery 5, and equation (6) is an observation equation related to the observed value of the secondary battery 5. In the following equations (5) and (6), "k" indicates an index of the discretized time (kth time, hereinafter may be referred to as time k).

In the above equations (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 equation (7), the SOC value and voltage at time k. u1 and voltage u2. Further, "i _k " is the above-mentioned current observation value i which is a control input from the outside, and "y _k " is the voltage across the secondary battery 5 at time k as shown in the above equation (8). Is. Note that "A", "B", "C", and "D" are, for example, matrices obtained from the above (1) to (4).

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

FIG. 4 is a diagram showing an example of SOC-OCV characteristics of the secondary battery 5. In FIG. 4, the horizontal axis is SOC (%) and the vertical axis is OCV (V). The charge state estimation unit 21 tentatively estimates the SOC value based on the OCV value estimated using the system model and the SOC-OCV characteristics shown in FIG. The charge state estimation unit 21 corrects the tentatively estimated SOC value with a Kalman filter based on the observation error which is the difference between the estimated value of the voltage across the both ends u estimated using the above system model and the voltage observed value u. By using the SOC value as the estimated value of SOC, the SOC value is finally estimated.

Hereinafter, the SOC estimation calculation by the charge state estimation unit 21 will be described more specifically, including the process when the use of the secondary battery 5 is resumed after the use of the secondary battery 5 is stopped. In the following, the discretized time index "k" shall be described in parentheses instead of the subscript.

[2.1. Configuration of charge state estimation unit 21]
FIG. 5 is a functional block diagram of the charge state estimation unit 21. As shown in FIG. 5, the charge 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. And prepare. 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. When the CPU of the microcomputer reads and executes the program stored in the ROM or the flash memory, it functions as a calculation unit 42, a determination unit 43, and an initial value setting unit 44. Further, the storage unit 40 is configured by a RAM or the like.

The calculation unit 42, the determination unit 43, and the initial value setting unit 44 may be entirely or partially configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). Further, the above-mentioned program can be read from a recording disc (for example, a CD or DVD) by a reading unit (not shown) and stored in a ROM or a flash memory.

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

The A / D conversion unit 41 repeatedly digitally converts the voltage observation value u output from the voltage sensor 11 at predetermined time intervals, and outputs the voltage observation value u (k). Further, the A / D conversion unit 41 repeatedly digitally converts the current observation value i output from the current sensor 12 at predetermined time intervals, and outputs 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 ex post facto state estimation value x ^ (k-1) and various parameters of the equivalent circuit model 30 from the storage unit 40.

The ex post facto state estimated value x ^ (k-1) is a state vector of the secondary battery 5 actually estimated by the charge state estimation unit 21 at time k1-1. Here, the state estimated value x (k), which is the state vector of the secondary battery 5 at time k, is represented by the following equation (9), and the SOC value SOC (k), the voltage u1 (k), and the voltage u2 ( k) is included.

The battery state estimation unit 50 is based on the post-state estimation value x ^ (k-1), the voltage observation value u (k), and the current observation value i (k), and the pre-state estimation value x ^-(k). Is calculated. For example, the battery state estimation unit 50 can obtain the preliminary state estimation value x ^-(k) by performing the calculation of the following formula (10) corresponding to the above formula (5). Further, the observed current 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 ex-post state estimated value x ^ (k-1), the current observed value i (k), and the pre-state estimated value. It is a function showing the relationship with x ^-(k). Although the current observed value i (k) is used in the above equation (10), the current observed value i (k-1) may be used.

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

Further, the battery state estimation unit 50 calculates the 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 to (k) by performing the calculation of the following equation (13). The battery state estimation unit 50 outputs the difference u to (k) to the gain setting unit 51.

The gain setting unit 51 acquires the difference u to (k) from the battery state estimation unit 50, and acquires the observed noise Σ _w and the system noise Σ _v from the storage unit 40. The gain setting unit 51 calculates the Kalman gain G (k) based on the difference u to (k), the posterior error covariance matrix P (k-1), the observed noise Σ _w , and the system noise Σ _v . do. The observed noise Σ _w is the covariance of the above-mentioned observation noise w _k , and the system noise Σ _v is the covariance of the above-mentioned system noise v _k .

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

Next, the gain setting unit 51 calculates the Kalman gain G (k) based on the prior error covariance matrix P- (k) and the system noise Σ _v at time 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 pre-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 post-state estimated value x ^ (k) based on the pre-state estimated value x ^-(k) and the Kalman gain G (k). Specifically, the filter unit 52 corrects the pre-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 post-state estimated value x ^ (k) based on the pre-state estimated value x ^-(k) and the modified values x ~ (k). For example, the filter unit 52 can obtain the ex-post state estimated value x ^ (k) by the calculation of the following equation (19).

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

The filter unit 52 stores the extracted ex-post state estimated value x ^ (k) in the storage unit 40, and outputs the calculated ex-post state estimated value SOC ^ (k) to the vehicle control device 2. 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. Is.

The calculation method of the ex post facto state estimated value SOC ^ (k) is not limited to the above-mentioned example. As for the calculation method of the post-state estimated value SOC ^ (k), it is sufficient that the post-state estimated value SOC ^ (k) can be calculated by the estimation calculation using the equivalent circuit model. For example, the charging state estimation unit 21 can also calculate the post-state estimated value SOC ^ (k) by a known estimation process.

[2.2. Initial value SOC (0) setting process]
As described above, the charge state estimation unit 21 includes a storage unit 40, a determination unit 43, and an initial value setting unit 44. The determination unit 43 determines whether or not the use of the secondary battery 5 is 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 previous final value (second initial value) of the SOC stored in the storage unit 40 is valid. The last SOC last value is the post-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) at the post-state estimated value x ^ (k-1) at time k-1 when the time for restarting the estimation calculation is time k. Is. Thereby, the battery state estimation unit 50 can calculate the preliminary state estimation value x ^-(k) by using, for example, the above equation (10).

[2.2.1. Information stored in the storage unit 40]
The storage unit 40 stores a table or an arithmetic expression showing SOC-OCV characteristics. FIG. 6 is a diagram showing an example of a table showing SOC-OCV characteristics. The table showing the SOC-OCV characteristics 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)". ) ”Is associated.

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

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

FIG. 8 is a diagram showing the relationship between the second variation range AR2 and the OCV value in the discharge information. In the example shown in FIG. 8, for example, the OCV value “3.30 (V)” is associated with the second variation range AR2 “73.0 to 78.0 (%)”, and the OCV value “3.29). A 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 shown in FIG. 5 determines whether or not the use of the secondary battery 5 is resumed after the set time T1 has elapsed since the use of the secondary battery 5 was stopped. Specifically, the determination unit 43 counts the stop time Tx from the stop timing at which the use of the secondary battery 5 is stopped until 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 counter count at the start timing when the suspension of use of the secondary battery 5 is released, and set the count value of the counter as the stop time Tx.

The determination unit 43 determines, for example, that it is the stop timing when the ignition signal _SIGN changes from the state of indicating ON of the ignition to the state of indicating OFF of the ignition. Further, when the ignition signal _SIGN changes from the state of indicating the ignition OFF to the state of indicating the ignition ON, the determination unit 43 determines that it is the activation timing.

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 is resumed before the set time T1 elapses after the use of the secondary battery 5 is 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 is 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 the time required to eliminate the polarization of the secondary battery 5 (hereinafter referred to as the polarization elimination time), and whether or not the polarization of the secondary battery 5 is eliminated by this. Can be determined.

Further, the determination unit 43 determines whether or not the previous final value of the SOC stored in the storage unit 40 is valid. The fact that the previous final value of SOC is valid means that the last final value of SOC 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 the 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.

[2.22.3. 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) depending on whether the stop time Tx is the set time T1 or more and the stop time Tx is less than the set time T1. Further, 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 previous final value of the SOC is valid.

Further, the initial value setting unit 44 may obtain a plurality of SOC values by different methods regardless of the stop time Tx when the minimum value priority setting that prioritizes the minimum value among the plurality of SOC values obtained by different methods described later is effective. The lowest SOC value among the SOC values of can be set as the initial value SOC (0). Hereinafter, each case will be specifically described.

[2.2.3.1. When Tx ≧ T1]
The initial value setting unit 44 determines the SOC value to be set to the initial value SOC (0) by the first method and sets it in the battery state estimation 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 receives 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.

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 information indicating the SOC-OCV characteristics stored in the storage unit 40, and sets 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 SOC value “77.5%” is set as the initial value SOC (0) and the battery state. It is set in the estimation unit 50.

When Tx ≧ T1, the polarization elimination time of the secondary battery 5 has elapsed, so that 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 the output is output from the A / D conversion unit 41. It is assumed that the observed voltage value u (k) is regarded as an OCV value, but the present invention is not limited to this example. For example, the initial value setting unit 44 sets the SOC value corresponding to the OCV value corresponding to 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.

Further, the storage unit 40 can store information (table or arithmetic expression) indicating the 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 corresponding to the voltage observation value u (k) output from the A / D conversion unit 41 immediately after the start timing in the storage unit 40. It can also be extracted from the information showing the characteristics. The CCV value is the closed circuit voltage of the secondary battery 5.

[2.2.3.2. When Tx <T1 and the last final value of SOC is valid]
When the initial value setting unit 44 determines by the determination unit 43 that the stop time Tx is less than the set time T1 and the previous final value of the SOC stored in the storage unit 40 is valid, the second method is used. , 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 previous final value stored in the storage unit 40 as the initial value SOC (0) in the battery state estimation unit 50. As described above, the last SOC last value is the post-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 voltage observation value u (k), but the superimposed polarization voltage is caused by charging. It is not possible to determine whether the polarization voltage is due to the discharge or the polarization voltage due to the discharge from the observed voltage value u (k).

Therefore, when the SOC value corresponding to the voltage observation value u (k) is extracted from the information indicating the SOC-OCV characteristics and the initial value SOC (0) is set, the deviation between the initial value SOC (0) and the true value is large. It becomes large, and the convergence of the ex-post state estimated value SOC ^ (k) may be delayed.

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

[2.22.3.3. Tx <T1 and SOC last time final value is not valid]
When the initial value setting unit 44 determines by the determination unit 43 that the stop time Tx is less than the set time T1 and the previous final value of the SOC stored in the storage unit 40 is not valid, the third method is used. , 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 observed value u (k) as the initial value SOC (0) based on the charging information and the discharging 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 CV in the overlap 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) as the initial value. It can be determined as SOC (0). Here, the charging information stored in the storage unit 40 is in the state shown in FIG. 7, the discharging 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 to 79.5 (%)", which is the same as the voltage observation value u (k). The second variability range AR2 associated with the matching OCV values is "72.5-77.5 (%)". Therefore, the overlap range AR3 is "74.5 to 77.5 (%)", and the median CV of the overlap range AR3 is "76.0 (%)". Therefore, the initial value setting unit 44 determines "76.0 (%)" as the 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), but the superimposed polarization. Whether the voltage is a polarization voltage due to charging or a polarization voltage due to discharge cannot be determined from the observed voltage u (k).

Therefore, when Tx <T1 and the previous final value of SOC is not valid, the initial value setting unit 44 sets the median value CV of the overlap range AR3 between the variation range AR1 of the SOC value at the time of charging and the variation range AR2 of the SOC value at the time of discharging. Is determined as the initial value SOC (0). Since the initial value SOC (0) is determined from within the overlap range AR3, the initial value SOC (0) deviates significantly from the true value regardless of whether the polarization is caused by charging or discharging. Can be suppressed. Therefore, the convergence of the ex-post 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 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 CV corresponding to the OCV value that matches the voltage observed value u (k) from the storage unit 40.

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

Further, the storage unit 40 can store charge / discharge information indicating whether the secondary battery 5 is in a charged state or a discharged state immediately before the stop timing. The initial value setting unit 44 can determine whether the secondary battery 5 is in a charged state or a discharged state immediately before the stop timing, based on the charge / discharge information stored in the storage unit 40. ..

When the secondary battery 5 is 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). Further, when the secondary battery 5 is in a state of being discharged immediately before the stop timing, the initial value setting unit 44 may determine the center value of the second variation range AR2 as the initial value SOC (0). can.

[2.2.3.4. If the minimum 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 above-mentioned first to third methods as the initial value SOC (0). It is set in the battery state estimation unit 50.

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

When the minimum value priority setting is effective, the initial value setting unit 44 performs a process of obtaining a plurality of SOC values by the above-mentioned first to third methods, and determines the smallest SOC value among the plurality of SOC values. It is determined as the initial value SOC (0) and set in the battery state estimation unit 50.

In the estimation calculation using the Kalman filter, the convergence of the ex post facto state estimated value SOC ^ (k) is higher when the initial value SOC (0) is smaller than when it 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 ex-post state estimated value SOC ^ (k) can be improved, and the SOC can be improved. The accuracy of value estimation can be improved.

When the determination unit 43 determines that the SOC previous final value stored in the storage unit 40 is not valid, the SOC previous final value obtained by the second method can not be used. As a result, it is possible to prevent the estimation accuracy of the SOC value from being lowered.

Further, even when the determination unit 43 determines that the previous final value of the SOC stored in the storage unit 40 is valid, the initial value setting unit 44 is 2 out of the above-mentioned first to third methods. 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 above-mentioned plurality of SOC values as the initial value SOC (only when Tx ≧ T1). It can be determined as 0). Further, even when the minimum value priority setting is valid, the initial value setting unit 44 sets the smallest SOC value among the above-mentioned plurality of SOC values as the initial value SOC (only when Tx <T1). It can also be determined as 0).

In the above-mentioned example, the calculation unit 42, the determination unit 43, and the initial value setting unit 44 have been described separately, but the calculation unit 42 is provided with the 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-mentioned processing by the determination unit 43 and the initial value setting unit 44.

Further, in the above-mentioned example, the SOC previous final value was used as the second initial value, but the second initial value is the post-state estimated value SOC ^ (k) stored in the storage unit 40 immediately before the stop timing. ) May be the post-state estimated value SOC ^ (kn) stored in the storage unit 40 before n (n is a natural number) step.

Further, the initial value setting unit 44 may set the post-state estimated value SOC ^ (kn) as the initial value SOC (0) when the previous final value of SOC is not valid.

Further, 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 estimate SOC ^ (k). For example, the initial value setting unit 44 has the posterior state estimated value u1 ^ (k) and the posterior state estimated value u2 ^ (k) 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 the flow of processing executed by the charge state estimation unit 21, which is an example of the estimation device, will be described with reference to the flowchart. FIG. 9 is a flowchart showing an example of the 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 unit 43 of the charge state estimation unit 21 determines whether or not the ignition is ON (step S10). When the determination unit 43 determines that the ignition is ON (step S10; Yes), the determination unit 43 determines whether or not the ignition has just changed from OFF to ON (step S11). When the determination unit 43 determines that the ignition has just changed from OFF to ON (step S11: Yes), the initial value setting unit 44 of the charge state estimation unit 21 performs the determination process of the initial value SOC (0). (Step S12).

Next, the initial value setting unit 44 of the charge state estimation unit 21 sets the initial value SOC (0) determined in step S12 in the calculation unit 42 of the charge state estimation unit 21 (step S13). The calculation unit 42 of the charge state estimation unit 21 performs the SOC value estimation calculation when the determination unit 43 determines that the ignition is not immediately after the ignition is turned from OFF to ON when the step S13 is completed (step S10: No). Execute (step S14). The calculation unit 42 includes an initial value SOC (0) when the determination unit 43 determines that step S13 is completed and the ignition has just changed from OFF to ON (step S11: Yes). The SOC value estimation calculation is executed based on the initial value x ^ (0), the voltage observation value u (k), and the current observation value i (k). Further, when the determination unit 43 determines that the ignition is not immediately after the ignition is changed from OFF to ON (step S11: No), the calculation unit 42 determines the post-state estimated value x ^ (k-1) and the voltage observation value u. The SOC value estimation operation is executed based on (k) and the current observed value i (k).

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

When the determination unit 43 determines that the ignition is not ON (step S10: No), the charge state estimation unit 21 counts the stop time Tx (step S17). When the process of step S15 or the process of step S17 is completed, the process shown in FIG. 9 is terminated.

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 the determination unit 43 determines 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 the set time T1 or more (step S21). 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 of the charge state estimation unit 21 is based on the voltage observation value u (k). The initial value SOC (0) is determined from the SOC-OCV characteristics (step S22).

When 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 previous final value of the SOC stored in the storage unit 40 is valid (step S23). When the determination unit 43 determines that the SOC previous final value is valid (step S23: Yes), the initial value setting unit 44 sets the SOC previous final value stored in the storage unit 40 to the initial value SOC (0). Determine (step S24).

When the determination unit 43 determines that the last final value of the SOC is not valid (step S23: No), the initial value setting unit 44 is charged and discharged from the voltage observed value u (k) which is the voltage observed value. The median CV of the overlap range AR3 of the variation range AR1 and AR2 of the SOC value is determined to be the initial value SOC (0) (step S25).

When the determination unit 43 determines in step S20 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 charge state estimation unit 21 (an example of the estimation device) according to the embodiment includes an A / D conversion unit 41 (an example of an observation value acquisition unit), a calculation unit 42, and a storage unit 40. The A / D conversion unit 41 acquires voltage observation values u (k) and i (k) (an example of observation values of voltage u and current i of the secondary battery 5). The calculation unit 42 performs an estimation calculation using the equivalent circuit model 30 of the secondary battery 5 based on the voltage observation values u (k) and i (k) acquired by the A / D conversion unit 41, and the secondary battery 5 The post-state estimated value SOC ^ (k) (an example of the SOC value) indicating the charging state of is estimated. The storage unit 40 stores the post-state estimated value SOC ^ (k) estimated by the arithmetic unit 42. When the stop time Tx from the stop of use of the secondary battery 5 to the release of the stop 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 set 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 the value determined according to whether or not the previous final value of the SOC stored in the storage unit 40 (an example of the previous SOC value) is valid as the initial value SOC (0) before the use of the is stopped. As a result, even when the polarization voltage is superimposed on the voltage of the secondary battery 5 when the power supply system 1 is started, it is possible to suppress the deterioration of the estimation accuracy of the SOC value, and further, the previous final value of the SOC is effective. Since the value determined according to whether or not it is set to the initial value SOC (0), the estimation accuracy of the SOC value can be improved.

Further, when the stop time Tx is less than the set time T1, the calculation unit 42 sets the SOC last time final value as the initial value SOC (0) if the SOC last time final value is valid, and the SOC last time final value must be valid. For example, the value determined based on the observed voltage value u (k) is defined as the initial value SOC (0). As a result, the estimation accuracy of the SOC value can be improved as compared with the case where the invalid SOC previous final value is used as the SOC initial value.

Further, the storage unit 40 has charging information (an example of the first information) showing the 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 the discharge information (an example of the second information) showing the relationship between the voltage (OCV or CCV) of the secondary battery 5 and the SOC value when the secondary battery 5 is discharged is stored. When the stop time Tx is less than the set time T1, the calculation unit 42 determines the SOC previous final value to 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 information and the discharging information. As a result, since the value using both the charging information and the discharging information is set as the initial value SOC (0), it is possible to prevent the initial value SOC (0) from deviating significantly from the true value. Therefore, the convergence of the ex-post state estimated value SOC ^ (k) can be improved, and the estimation accuracy of the SOC value can be improved.

Further, the charging information includes the relationship between the voltage (OCV value or CCV value) of the secondary battery 5 when the secondary battery 5 is charging and the first variation range AR1 which is the variation range of the SOC value. Contains information to indicate. The discharge information includes information indicating the relationship between the voltage (OCV value or CCV value) of the secondary battery 5 when the secondary battery 5 is discharged and the second variation range AR2 which is the variation range of the SOC value. Is included. If the last final value of SOC is not valid, the calculation unit 42 sets the median CV in the overlap range AR3 of the first variation range AR1 and the second variation range AR2 corresponding to the voltage observation value u (k) as the initial value. The estimation calculation is performed as SOC (0). As a result, it is possible to more accurately suppress the deviation of the initial value SOC (0) from the true value, and it is possible to improve the convergence of the ex post facto 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 the plurality of SOC values obtained by different methods is effective, the arithmetic unit 42 initially resets the smallest SOC value among the plurality of SOC values obtained by different methods. The estimation operation is performed with the value SOC (0). As a result, it is possible to improve the convergence of the ex-post state estimated value SOC ^ (k) and improve the estimation accuracy of the SOC value.

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

1 Power supply system 2 Vehicle control device 3 Motor 4 Power conversion unit 5 Secondary battery 6 Battery monitoring system 7 Relay 10 Battery status monitoring unit 11 Voltage sensor 12 Current sensor 20 Switch control unit 21 Charge status estimation unit (example of estimation device)
30 Equivalent circuit model 40 Storage unit 41 A / D conversion unit (an example of observation value acquisition unit)
42 Calculation unit 43 Judgment unit 44 Initial value setting unit 50 Battery status estimation unit 51 Gain setting unit 52 Filter unit 100 Vehicle mounting system

Claims (5)

An observation value acquisition unit that acquires the observation values of the voltage and current of the secondary battery,
Based on the observation value acquired by the observation value acquisition unit, the calculation unit that estimates the SOC value indicating the charge state of the secondary battery by the estimation calculation using the equivalent circuit model of the secondary battery, and the calculation unit.
A storage unit that stores the SOC value estimated by the calculation unit, and a storage unit that stores the SOC value.
If the previous SOC value, which is the SOC value stored in the storage unit before the use of the secondary battery is stopped, is not within the normal range, or if there is data corruption, the previous SOC value must be invalid. Equipped with a determination unit for determination
The arithmetic unit
When the stop time from the stop of use of the secondary battery to the release of the stop is equal to or longer than a preset time, a value determined based on the observed value of the voltage is used as the SOC in the estimation calculation. When the estimation calculation is started by the first method of setting the initial value of the value and the stop time is less than the preset time, if the previous SOC value is valid, the previous SOC value is used as the initial value. If the previous SOC value is not valid in the second method using the value, the estimation calculation is started by the third method in which the value determined based on the observed value of the voltage is used as the initial value. ,
The storage unit further
The first information indicating the relationship between the open circuit voltage of the secondary battery and the SOC value when the secondary battery is being charged, and the secondary battery when the secondary battery is being discharged. The second information indicating the relationship between the open circuit voltage and the SOC value is stored, and the second information is stored.
The arithmetic unit further
If the stop time is less than the preset time and the previous SOC value is not valid, the initial value is based on the first information and the second information as the third method. To decide
An estimation device characterized by that. The first information mentioned above includes
Information indicating the relationship between the open circuit voltage of the secondary battery and the first variation range, which is the variation range of the SOC value, when the secondary battery is being charged is included.
The second information mentioned above includes
Information indicating the relationship between the open circuit voltage of the secondary battery and the second variation range, which is the variation range of the SOC value, when the secondary battery is discharged is included.
The arithmetic unit
If the previous SOC value is not valid, the estimation calculation is performed with the median value in the overlap range between the first variation range and the second variation range corresponding to the observed value of the voltage as the initial value. The estimation device according to claim 1 . The arithmetic unit
When the minimum value priority setting that prioritizes the minimum value among the plurality of SOC values obtained by the three methods of the first method, the second method, and the third method is effective, the above three methods are used. The estimation device according to claim 1 or 2 , wherein the estimation operation is performed with the smallest SOC value among the obtained plurality of SOC values as the initial value. The observation value acquisition process for acquiring the observed values of the voltage and current of the secondary battery, and
Based on the observed value acquired in the observed value acquisition step, the calculation step of estimating the SOC value indicating the charge state of the secondary battery by the estimation calculation using the equivalent circuit model of the secondary battery, and the calculation step.
A storage process for storing the SOC value estimated by the calculation process in the storage unit, and a storage process.
If the previous SOC value, which is the SOC value stored in the storage unit before the use of the secondary battery is stopped, is not within the normal range, or if there is data corruption, the previous SOC value must be invalid. Including the determination step of determination
The calculation process is
When the stop time from the stop of use of the secondary battery to the release of the stop is equal to or longer than a preset time, a value determined based on the observed value of the voltage is used as the SOC in the estimation calculation. When the estimation calculation is started by the first method of setting the initial value of the value and the stop time is less than the preset time, if the previous SOC value is valid, the previous SOC value is used as the initial value. If the previous SOC value is not valid in the second method using the value, the estimation calculation is started by the third method in which the value determined based on the observed value of the voltage is used as the initial value. ,
The storage step further
The first information indicating the relationship between the open circuit voltage of the secondary battery and the SOC value when the secondary battery is being charged, and the secondary battery when the secondary battery is being discharged. The second information indicating the relationship between the open circuit voltage and the SOC value is stored, and the second information is stored.
The calculation process further
If the stop time is less than the preset time and the previous SOC value is not valid, the initial value is based on the first information and the second information as the third method. To decide
An estimation method characterized by that. The observation value acquisition procedure for acquiring the observed value of the voltage and current of the secondary battery, and
Based on the observation value acquired in the observation value acquisition procedure, the calculation procedure for estimating the SOC value indicating the charge state of the secondary battery by the estimation calculation using the equivalent circuit model of the secondary battery, and the calculation procedure.
A storage procedure for storing the SOC value estimated by the calculation procedure in the storage unit, and a storage procedure for storing the SOC value in the storage unit.
If the previous SOC value, which is the SOC value stored in the storage unit before the use of the secondary battery is stopped, is not within the normal range, or if there is data corruption, the previous SOC value must be invalid. Let the computer execute the judgment procedure to judge
The calculation procedure is
When the stop time from the stop of use of the secondary battery to the release of the stop is equal to or longer than a preset time, a value determined based on the observed value of the voltage is used as the SOC in the estimation calculation. When the estimation calculation is started by the first method of setting the initial value of the value and the stop time is less than the preset time, if the previous SOC value is valid, the previous SOC value is used as the initial value. If the previous SOC value is not valid in the second method using the value, the estimation calculation is started by the third method in which the value determined based on the observed value of the voltage is used as the initial value. ,
The memory procedure further
The first information indicating the relationship between the open circuit voltage of the secondary battery and the SOC value when the secondary battery is being charged, and the secondary battery when the secondary battery is being discharged. The second information indicating the relationship between the open circuit voltage and the SOC value is stored, and the second information is stored.
The calculation procedure further
If the stop time is less than the preset time and the previous SOC value is not valid, the initial value is based on the first information and the second information as the third method. To decide
An estimation program characterized by that.

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