JP5989320B2 - Vehicle control apparatus and remaining capacity estimation method - Google Patents

Description

  The present invention relates to a technique for accurately estimating the remaining capacity of a lithium ion battery mounted on a vehicle.

  Japanese Patent Laid-Open No. 2000-166109 (Patent Document 1) estimates the SOC with high accuracy by correcting the first SOC according to the difference between the first SOC based on the integrated value of the current and the second SOC based on the battery voltage. Technology is disclosed.

JP 2000-166109 A

  By the way, in a lithium ion battery, when charging / discharging of a large current is continued due to uphill / downhill running or the like, there is a problem in that the salt concentration of the electrolytic solution is biased in the electrode plate and the internal resistance is increased. The estimation accuracy of the remaining capacity of the lithium ion battery based on the voltage may deteriorate due to the increase in internal resistance.

  The present invention has been made to solve the above-described problems, and its object is to suppress deterioration in estimation accuracy of the remaining capacity of a lithium ion battery when charging / discharging of a large current is continued. A vehicle control device and a remaining capacity estimation method are provided.

  A vehicle control device according to an aspect of the present invention is a vehicle control device mounted on a vehicle including a drive motor and a lithium ion battery for supplying power to the drive motor. The vehicle control device calculates a correction amount of the remaining capacity of the lithium ion battery based on a detection unit for detecting the current and voltage of the lithium ion battery and the integrated value of the current, and calculates the calculated correction amount And a control unit for estimating the remaining capacity based on the estimated value of the remaining capacity based on the voltage. The correction amount is a correction amount of the remaining capacity according to the distribution state of the salt concentration of the electrolytic solution between the electrode plates and at least one of the electrode plate surfaces in the lithium ion battery.

  Preferably, the control unit multiplies the basic value calculated based on the open voltage of the lithium ion battery and the battery temperature of the lithium ion battery by a first coefficient calculated based on the integrated value and the battery temperature. The correction amount is calculated.

  More preferably, the control unit calculates the basic value when the open circuit voltage is large so that the basic value is larger than when the open circuit voltage is small.

  More preferably, the control unit calculates the basic value so that the basic value is smaller when the battery temperature is high than when the battery temperature is low.

  More preferably, the control unit calculates the basic value based on the first map for calculating the basic value using the open circuit voltage, the battery temperature, and the open circuit voltage and the battery temperature as arguments.

  More preferably, the control unit calculates the first coefficient such that the first coefficient is larger when the integrated value is large than when the integrated value is small.

  More preferably, the control unit calculates the first coefficient such that the first coefficient is smaller when the battery temperature is high than when the battery temperature is low.

  More preferably, the control unit calculates the first coefficient based on a second map for calculating the first coefficient using the integrated value, the battery temperature, the integrated value, and the battery temperature as arguments.

  More preferably, the control unit calculates the correction amount by multiplying the basic value by the second coefficient calculated based on the estimated value of the full charge capacity of the lithium ion battery in addition to the first coefficient.

  More preferably, the control unit calculates the second coefficient so that the second coefficient is smaller when the full charge capacity is large than when the full charge capacity is small.

  More preferably, the control unit calculates the second coefficient based on a third map for calculating the second coefficient using the full charge capacity and the full charge capacity as arguments.

  More preferably, the control unit calculates an estimated value of the increase amount of the internal resistance based on the integrated value and the distribution state of the salt concentration, and calculates a correction amount based on the calculated estimated value.

More preferably, the lithium ion battery includes a rectangular battery cell.
A remaining capacity estimation method according to another aspect of the present invention is a method for estimating a remaining capacity of a lithium ion battery for supplying power to a driving motor mounted on a vehicle. The remaining capacity estimation method includes a step of calculating a correction amount of the remaining capacity of the lithium ion battery based on an integrated value of the current of the lithium ion battery, a calculated correction amount, and a remaining capacity based on the voltage of the lithium ion battery. Estimating a remaining capacity based on the estimated value. The correction amount is a correction amount of the remaining capacity according to the distribution state of the salt concentration of the electrolytic solution between the electrode plates and at least one of the electrode plate surfaces in the lithium ion battery.

  According to the present invention, the estimation accuracy of the remaining capacity based on the voltage affects the estimation accuracy of the internal resistance. Further, the increase in internal resistance caused by the uneven salt concentration of the electrolyte in the electrode plate of the lithium ion battery depends on the integrated value of the current to the lithium ion battery. That is, by calculating the correction amount of the remaining capacity based on the integrated value of the current, it is possible to suppress the deterioration of the estimation accuracy of the remaining capacity based on the voltage. Therefore, charging and discharging with a large current is continued, and the remaining capacity can be estimated with high accuracy even when the internal resistance is increased due to a deviation in the salt concentration of the electrolyte in the electrode plate of the lithium ion battery. Therefore, it is possible to provide a vehicle control device and a remaining capacity estimation method that suppress deterioration in the estimation accuracy of the remaining capacity of a lithium ion battery when charging and discharging with a large current continues.

1 is an overall block diagram of a vehicle equipped with a vehicle control device according to the present embodiment. It is a figure which shows the structure of a square lithium ion battery cell. It is a figure which shows an example of the distribution state of the salt concentration in an electrode plate surface. It is a figure which shows an example of the change of the voltage VB at the time of discharge, real OCV, and OCV estimated value. It is a functional block diagram of ECU which is a control device for vehicles concerning this embodiment. It is a figure which shows an example of the 1st map for calculating basic value Ba. It is a figure which shows an example of the 2nd map for calculating 1st gain Ga. It is a figure which shows an example of the 3rd map for calculating 2nd gain Gb. It is a flowchart which shows the control structure of the program performed by ECU which is the vehicle control apparatus which concerns on this Embodiment. It is a figure which shows the relationship between the SOC estimated value before correction | amendment, and the SOC estimated value after correction | amendment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, an overall block diagram of a vehicle 1 according to the present embodiment will be described. The vehicle 1 includes a wheel 2, a transmission 10, a PCU (Power Control Unit) 24, a battery 26, a charging device 78, and an ECU (Electronic Control Unit) 200.

  The transmission 10 includes a motor generator (hereinafter referred to as MG) 14 and a speed reducer 8. The MG 14 and the speed reducer 8 are connected by a drive shaft 16. The vehicle 1 travels with the driving force output from the MG 14. MG14 is, for example, a three-phase AC rotating electric machine. The MG 14 is driven by the PCU 24.

  The MG 14 has a function as a driving motor that applies a driving force to the wheels 2 using the electric power stored in the battery 26. Further, the MG 14 has a function as a generator for charging the battery 26 via the PCU 24 using the electric power generated by the regenerative braking.

  The speed reducer 8 transmits the power from the MG 14 to the wheels 2. Further, the speed reducer 8 transmits the reaction force from the road surface received by the wheels 2 to the MG 14.

  The PCU 24 converts the DC power stored in the battery 26 into AC power for driving the MG 14. PCU 24 includes a converter and an inverter (both not shown) controlled based on control signal S1 from ECU 200. The converter boosts the voltage of the DC power received from battery 26 and outputs it to the inverter. The inverter converts the DC power output from the converter into AC power and outputs the AC power to MG 14. Thereby, MG 14 is driven using the electric power stored in battery 26. The inverter converts AC power generated by the MG 14 into DC power and outputs it to the converter. The converter steps down the voltage of the DC power output from the inverter and outputs it to the battery 26. Thereby, the battery 26 is charged using the electric power generated by the MG 14. The converter may be omitted.

  The battery 26 is a power storage device and is a rechargeable DC power source. In the present embodiment, the battery 26 will be described using, for example, a lithium ion battery as an example. However, when charging / discharging of a large current is continued, the battery 26 is a salt of the electrolyte between internal electrode plates or electrode plate surfaces. The battery is not particularly limited to a lithium ion battery as long as the battery has a characteristic that the internal resistance increases due to concentration deviation.

  Further, in the present embodiment, the battery 26 includes one or more rectangular battery cells 72 as shown in FIG. As shown in FIG. 2, the battery cell 72 includes a sheet-like positive electrode plate and a negative electrode plate. The sheet-like positive electrode plate and the negative electrode plate are stacked with a sheet-like separator interposed therebetween. The sheet-like positive electrode plate, the negative electrode plate, and the separator are wound in a spiral shape and stored in a rectangular parallelepiped container in a deformed state so as to reduce the thickness. The inside of the container is filled with an electrolytic solution. The battery cell 72 is limited to a square shape as long as the battery cell 72 has a shape that causes a deviation in the salt concentration of the electrolyte solution between the electrode plates inside or between the electrode plates when charging and discharging with a large current continues. Instead, for example, it may be cylindrical.

  Returning to FIG. 1, the battery 26 is provided with a battery temperature sensor 156, a current sensor 158, and a voltage sensor 160.

  The battery temperature sensor 156 detects the battery temperature TB of the battery 26. Battery temperature sensor 156 transmits a signal indicating battery temperature TB to ECU 200.

  Current sensor 158 detects current IB of battery 26. Current sensor 158 transmits a signal indicating current IB to ECU 200.

  The voltage sensor 160 detects the voltage VB of the battery 26. Voltage sensor 160 transmits a signal indicating voltage VB to ECU 200.

  ECU 200 estimates the remaining capacity of the battery (described as SOC (State Of Charge) in the following description) based on current IB of battery 26, voltage VB, and battery temperature TB. For example, ECU 200 estimates an OCV (Open Circuit Voltage) based on current IB, voltage VB, and battery temperature TB, and estimates the SOC of battery 26 based on the estimated OCV and a predetermined map. Alternatively, ECU 200 estimates the SOC of battery 26 by, for example, integrating the charging current and discharging current of battery 26. ECU 200 estimates the SOC of battery 26 based on at least one of OCV and current integration, for example, according to the state of vehicle 1.

  The resolver 12 is provided in the MG 14. The resolver 12 detects the rotational speed Nm of the MG 14. The resolver 12 transmits a signal indicating the detected rotation speed Nm to the ECU 200.

  The wheel speed sensor 22 detects the rotational speed Nw of the wheel 2. The wheel speed sensor 22 transmits a signal indicating the detected rotational speed Nw to the ECU 200. ECU 200 calculates vehicle speed V based on the received rotational speed Nw. ECU 200 may calculate vehicle speed V based on rotation speed Nm of MG 14 instead of rotation speed Nw.

  The charging device 78 charges the battery 26 using electric power supplied from the external power source 302 when the charging plug 300 is attached to the vehicle. Charging plug 300 is connected to one end of charging cable 304. The other end of charging cable 304 is connected to external power supply 302. The positive terminal of the charging device 78 is connected to a power supply line that connects the positive terminal of the PCU 24 and the positive terminal of the battery 26. The negative terminal of the charging device 78 is connected to an earth line that connects the negative terminal of the PCU 24 and the negative terminal of the battery 26. Charging device 78 operates based on control signal S3 from ECU 200.

  The start switch 150 is, for example, a push switch. The start switch 150 may be configured to insert a key into a key cylinder and rotate it to a predetermined position. Start switch 150 is connected to ECU 200. In response to the driver operating the start switch 150, the start switch 150 transmits a signal ST to the ECU 200.

  For example, when the signal ST is received when the system of the vehicle 1 is in a stopped state, the ECU 200 determines that an activation instruction has been received, and shifts the system of the vehicle 1 from the stopped state to the activated state. Further, when the signal ST is received when the system of the vehicle 1 is in the activated state, the ECU 200 determines that the stop instruction has been received, and shifts the system of the vehicle 1 from the activated state to the stopped state.

  In the following description, the operation of the start switch 150 by the driver when the system of the vehicle 1 is in the activated state is referred to as an IG off operation, and the driver operates the start switch 150 when the system of the vehicle 1 is in the stopped state. The operation is called IG on operation.

  Further, when the system of the vehicle 1 shifts to the activated state, power supply to the system of the vehicle 1 is started. When power supply to the system of the vehicle 1 is started, power is supplied to a plurality of devices necessary for the vehicle 1 to travel. As a result, a plurality of devices necessary for the vehicle 1 to travel can be operated.

  On the other hand, when the system of the vehicle 1 shifts to the stop state, the power supply to the system of the vehicle 1 is interrupted. When the power supply to the system of the vehicle 1 is cut off, the supply of electric power to some of a plurality of devices necessary for the vehicle 1 to travel is stopped (cut off). As a result, a plurality of devices necessary for the vehicle 1 to travel are in a stopped state. In addition, the power supply with respect to the apparatus which operate | moves during the system stop of the vehicle 1 is maintained.

  Equipment necessary for the vehicle 1 to travel includes, for example, an MG 14 and a PCU 24. Moreover, the apparatus which operate | moves during the stop of the system of the vehicle 1 contains ECU200 and the charging device 78, for example.

  The ECU 200 generates a control signal S1 for controlling the PCU 24 and outputs the generated control signal S1 to the PCU 24. Further, ECU 200 generates a control signal S2 for controlling charging device 78, and outputs the generated control signal S2 to charging device 78.

  ECU 200 calculates a required driving force corresponding to the amount of depression of an accelerator pedal (not shown) provided in the driver's seat. ECU 200 controls the torque of MG 14 in accordance with the calculated required driving force.

  ECU 200 includes a CPU (not shown) for executing various programs and a memory 201 for storing various programs.

  In the lithium ion battery mounted on the vehicle 1 having the above-described configuration, when charging / discharging of a large current is continued due to uphill / downhill driving or the like, the salt concentration of the electrolytic solution is uneven in the electrode plate, Resistance may increase. The estimation accuracy of the remaining capacity of the lithium ion battery based on the voltage may deteriorate due to the increase in internal resistance.

  As shown in FIG. 2, the rectangular battery cell is wound in a spiral shape and is stored in a rectangular parallelepiped container in a deformed state so as to reduce the thickness. In such a rectangular battery cell, the constituent elements in the battery cell contract due to charge / discharge, so that the pressure on the center side of the battery cell increases and the pressure on the end side decreases. As a result, the electrolytic solution flows, and for example, as shown in FIG. 3, the salt concentration distribution may not be uniform on the electrode plate surfaces of the positive electrode and the negative electrode. In this case, the movement of lithium ions is suppressed at locations where the salt concentration is low, which causes an increase in internal resistance. The distribution state of the salt concentration shown in FIG. 3 is an example, and is not limited to the distribution state shown in FIG.

  FIG. 4 shows an example of a change in voltage VB when discharging with a constant current IBa between time T (0) and time T (1). The vertical axis in FIG. 4 indicates the voltage VB, and the horizontal axis in FIG. 4 indicates time.

  When the discharge is started at time T (0), the voltage VB decreases as shown by the solid line in FIG. In addition, the OCV is reduced by the discharge as the SOC decreases. Since the OCV cannot be directly measured during discharge, the ECU 200 adds the change due to the internal resistance and the change due to polarization to the voltage VB detected by the voltage sensor 160 during discharge. Then, an OCV estimated value as shown by a broken line in FIG. 4 is calculated.

  However, when the internal resistance rises due to the above-described deviation of the salt concentration, the change in the internal resistance is estimated to be smaller than actual. Therefore, the OCV estimated value is estimated to be lower than the actual OCV (the one-dot chain line in FIG. 4). Similarly, during charging, the OCV estimated value is estimated to be higher than the actual OCV. As a result, the SOC estimation accuracy may deteriorate.

  Therefore, in the present embodiment, ECU 200 calculates SOC correction amount SOC_c of battery 26 based on integrated value IBs of current IB, and the estimated value of SOC based on calculated correction amount SOC_c and voltage VB. It is characterized in that the SOC of the battery 26 is estimated based on the SOC_e. The correction amount SOC_c is a correction amount of SOC according to the distribution state of the salt concentration of the electrolytic solution between at least one of the electrode plates and at least one of the electrode plate surfaces in the battery 26.

  FIG. 5 shows a functional block diagram of ECU 200 that is the vehicle control apparatus according to the present embodiment. ECU 200 includes an integrated value calculation unit 202, a correction amount calculation unit 204, and an SOC determination unit 206.

  The integrated value calculation unit 202 calculates the integrated value IBs by integrating the current IB detected by the current sensor 158. For example, the integrated value calculation unit 202 may integrate the current IB from the time when the system of the vehicle 1 is activated, and may end the accumulation of the current IB when the system of the vehicle 1 is stopped. Alternatively, for example, the integrated value calculation unit 202 integrates the current IB from the time when charging using the charging device 78 is started, and ends the integration of the current IB when charging using the charging device 78 is completed. Also good.

  The correction amount calculation unit 204 calculates the SOC correction amount SOC_c of the battery 26 based on the integrated value IBs of the current IB. Specifically, the correction amount calculation unit 204 multiplies the basic value Ba by a first coefficient (hereinafter referred to as a first gain Ga) and a second coefficient (hereinafter referred to as a second gain Gb). As a result, the correction amount SOC_c is calculated.

  The correction amount calculation unit 204 calculates the basic value Ba based on the OCV of the battery 26 and the battery temperature TB of the battery 26. In the present embodiment, correction amount calculation section 204 calculates basic value Ba based on estimated SOC value SOC_e based on OCV, battery temperature TB, and a predetermined first map. The predetermined first map is a map for calculating the basic value Ba using the estimated value SOC_e and the battery temperature TB as arguments.

  The correction amount calculation unit 204 estimates the OCV of the battery 26 by adding the change due to the internal resistance corresponding to the battery temperature TB and the change due to polarization to the voltage VB detected by the voltage sensor 160. The correction amount calculation unit 204 calculates the estimated SOC value SOC_e based on the OCV using the estimated OCV and a predetermined map.

  When the estimated value SOC_e is large, the correction amount calculating unit 204 calculates the basic value Ba so that the basic value Ba is larger than when the estimated value SOC_e is small. Further, the correction amount calculation unit 204 calculates the basic value Ba such that the basic value Ba is smaller when the battery temperature TB is high than when the battery temperature TB is low.

  Therefore, for example, a map as shown in FIG. 6 is used as the predetermined first map. In the map shown in FIG. 6, when the estimated value SOC_e is between 0% and SOC (0), the basic value Ba is a negative value, and the basic value Ba increases as the estimated value SOC_e increases. It is defined that the basic value Ba decreases as the estimated value SOC_e decreases. In the map shown in FIG. 6, the basic value Ba is zero when the estimated value SOC_e is between SOC (0) and SOC (1).

  Further, in the map shown in FIG. 6, between the estimated value SOC (1) and 100%, the basic value Ba is a positive value, and the basic value Ba is defined to increase as the estimated value SOC_e increases. The basic value Ba is defined to be smaller as the estimated value SOC_e is smaller.

  Further, in the map shown in FIG. 6, when the estimated value SOC_e is between 0% and SOC (0) and between SOC (1) and 100%, the basic value Ba is the basic value as the battery temperature TB increases. Ba is specified to increase, and the basic value Ba is specified to decrease as the battery temperature TB decreases.

  In the present embodiment, as shown in the map of FIG. 6, it is assumed that the estimated value SOC_e is zero regardless of the value of the battery temperature TB between SOC (0) and SOC (1). However, the basic value Ba may be defined such that the basic value Ba increases as the battery temperature TB increases even when the estimated value SOC_e is between SOC (0) and SOC (1). Alternatively, it may be defined that the basic value Ba increases as the estimated value SOC_e increases during the period from the estimated value SOC_e to SOC (0) SOC (1).

  By defining the basic value Ba as shown in the map of FIG. 6, the actual SOC does not exceed the upper limit value or the lower limit value when the use state of the battery 26 is a use state that increases the estimation error. The SOC can be controlled. The usage state of the battery 26 in which the estimation error is enlarged refers to, for example, a state where continuous charging / discharging of a large current is performed or a state where the battery 26 is deteriorated.

  The correction amount calculation unit 204 calculates the first gain Ga based on the integrated value IBs and the battery temperature TB. The first gain Ga is a coefficient that takes into account the amount of increase in internal resistance caused by the deviation of the salt concentration of the electrolytic solution between the electrode plates and at least one of the electrode plate surfaces in the lithium ion battery.

  In the present embodiment, correction amount calculation unit 204 calculates first gain Ga based on integrated value IBs, battery temperature TB, and a predetermined second map. The predetermined second map is a map for calculating the first gain Ga using the integrated value IBs and the battery temperature TB as arguments.

  The correction amount calculation unit 204 calculates the first gain Ga so that the value of the first gain Ga is larger when the integrated value IBs is larger than when the accumulated value IBs is small. Furthermore, the correction amount calculation unit 204 calculates the first gain Ga such that the value of the first gain Ga is smaller when the battery temperature TB is high than when the battery temperature TB is low.

  Therefore, for example, a map as shown in FIG. 7 is used as the predetermined second map. In the map shown in FIG. 7, the first gain Ga is defined such that the value of the first gain Ga decreases as the battery temperature TB increases. Further, in the map shown in FIG. 7, the first gain Ga is defined such that the value of the first gain Ga increases as the integrated value IBs of the current IB increases.

  For example, the first gain Ga is set to zero when the integrated value IBs is smaller than the predetermined integrated value IBs (0), and the first gain Ga is set to zero when the integrated value IBs is equal to or greater than the predetermined integrated value IBs (0). A larger value may be set. In this way, it is possible to correct the estimated value SOC_e only when charging / discharging with a large current is continued. Further, as the integrated value IBs increases, the value of the first gain Ga is increased to appropriately suppress the deterioration in estimation accuracy due to the increase in internal resistance caused by the salt concentration deviation of the electrolyte in the battery 26. be able to.

  The correction amount calculation unit 204 calculates the second gain Gb based on the full charge capacity FCC of the battery 26. The second gain Gb is a coefficient that considers the deterioration state of the battery 26.

  The correction amount calculation unit 204 calculates the second gain Gb based on the full charge capacity FCC of the battery 26 and a predetermined third map. The predetermined third map is a map for calculating the second gain Gb using the full charge capacity FCC as an argument.

  The correction amount calculation unit 204 calculates the second gain Gb so that the value of the second gain Gb is smaller when the full charge capacity FCC is large than when the full charge capacity FCC is small.

  Therefore, for example, a map as shown in FIG. 8 is used as the predetermined third map. In the map shown in FIG. 8, the second gain Gb is defined such that the value of the second gain Gb increases as the full charge capacity FCC decreases (as the battery 26 deteriorates).

  The full charge capacity FCC is calculated based on the integrated value IBs of the current IB and the SOC change ΔSOC based on the OCV during the integrated period of the integrated value IBs. The full charge capacity FCC is calculated using, for example, the formula FCC = IBs / ΔSOC × 100. The calculation method of the full charge capacity FCC is not particularly limited to the calculation method using the above formula. The full charge capacity FCC is calculated when the battery 26 is discharged or when the battery 26 is charged (for example, when the battery 26 is charged using the external power supply 302).

  For example, the second gain Gb is set to 1 when the full charge capacity FCC is larger than the predetermined full charge capacity FCC (0), and the second gain Gb is equal to or less than the predetermined full charge capacity FCC (0). The gain Gb may be set to a value larger than 1. In this way, it is possible to correct the estimated value SOC_e only when the battery 26 is in a deteriorated state.

In the present embodiment, the correction amount calculation unit 204 has been described as calculating the correction amount SOC_c based on the basic value Ba, the first gain Ga, and the second gain Gb. by the 1 gain G a may calculate the correction amount SOC_c.

  The SOC determination unit 206 calculates the corrected estimated value SOC_e ′ by adding the correction amount SOC_c to the estimated value SCO_e. The SOC determination unit 206 may determine the calculated estimated value SOC_e ′ as the SOC of the battery 26.

  Alternatively, the SOC determination unit 206 uses a known technique (for example, described in the above-mentioned publication) based on the calculated estimated value SOC_e ′ and the estimated value of the SOC of the battery 26 based on the separately calculated integrated value IBs of the current IB. The SOC of the battery 26 may be determined using the above technique.

  Alternatively, the SOC determination unit 206 uses either the estimated value SOC_e ′ or the estimated SOC value based on the separately calculated integrated value IBs of the current IB as the SOC of the battery 26 according to the state of the vehicle 1. It may be determined as

  For example, when it is known that only charging or discharging is performed, SOC determination unit 206 may determine the estimated value of SOC of battery 26 based on integrated value IBs as the SOC of battery 26. Alternatively, the SOC determination unit 206 may determine the estimated value SOC_e ′ as the SOC of the battery 26 when there is a possibility that the charging and discharging cycles are frequently repeated, for example, during traveling.

  The estimated value of the SOC of the battery 26 based on the integrated value IBs is estimated by, for example, the charge amount based on the charge current of the battery 26 in the integration period, the discharge amount based on the discharge current of the battery 26, and the initial value of the SOC. . The initial value of the SOC is, for example, the SOC at the time of the previous system stop.

  In the present embodiment, integrated value calculation unit 202, correction amount calculation unit 204, and SOC determination unit 206 are all realized by the CPU of ECU 200 executing a program stored in memory 201. However, it may be realized by hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  Referring to FIG. 9, a control structure of a program executed by ECU 200 that is the vehicle control apparatus according to the present embodiment will be described.

  In step (hereinafter referred to as “S”) 100, ECU 200 acquires battery temperature TB from battery temperature sensor 156, acquires current IB from current sensor 158, and acquires voltage VB from voltage sensor 160.

  In S102, ECU 200 calculates integrated value IBs of current IB. In S104, ECU 200 calculates correction amount SOC_c. Since the calculation method of correction amount SOC_c is as described above, detailed description thereof will not be repeated.

  In S106, ECU 200 calculates an estimated SOC value SOC_e '. Since the method for calculating estimated value SOC_e ′ is as described above, detailed description thereof will not be repeated.

  In S108, ECU 200 determines the SOC of battery 26 in accordance with the state of vehicle 1. Since the SOC determination method is as described above, detailed description thereof will not be repeated.

  The operation of ECU 200 that is the vehicle control apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  For example, the current IB, voltage VB, and battery temperature TB are acquired when the system of the vehicle 1 is activated by an IG-on operation or charging of the battery 26 using the external power supply 302 is started by the charging device 78. Is started (S100), and the integration of the current IB is started to calculate the integrated value IBs (S102).

  Based on the calculated integrated value IBs of the current IB, the correction amount SOC_c is calculated. Specifically, basic value Ba is calculated based on SOC estimated value SOC_e based on OCV and battery temperature TB. Further, the first gain Ga is calculated based on the battery temperature TB and the integrated value IBs. Further, the second gain Gb is calculated based on the full charge capacity FCC of the battery 26. Then, the correction value SOC_c is calculated by multiplying the calculated basic value Ba by the first gain Ga and the second gain Gb.

  An estimated value SOC_e 'is calculated by adding the calculated correction amount SOC_c to the estimated value SOC_e (S106), and the SOC of the battery 26 is determined according to the state of the vehicle 1 (S108).

  The relationship between the estimated value SOC_e ′ after correction and the estimated value SOC_e before correction is corrected by correcting the estimated value SOC_e with the correction amount SOC_c calculated according to the map shown in FIGS. The relationship is as shown by the solid line.

  In addition, the vertical axis | shaft of FIG. 10 shows estimated value SOC_e 'after correction | amendment. The horizontal axis in FIG. 10 indicates the estimated value SOC_e before correction. The broken line in FIG. 10 indicates the relationship between the estimated value SOC_e before correction and the estimated value SOC_e ′ after correction when the correction amount SOC_c is zero (that is, estimated value SOC_e = SOC_e ′).

  As shown in FIG. 6, when the estimated value SOC_e before correction is between SOC (0) and SOC (1), the basic value Ba is zero, so the correction amount SOC_c is also zero. Therefore, as shown in FIG. 10, when the estimated value SOC_e before correction is between SOC (0) and SOC (1), the estimated value SOC_e before correction and the estimated value SOC_e ′ after correction are the same value. Become.

  On the other hand, in the region where estimated value SOC_e before correction is smaller than SOC (0), estimated value SOC_e 'after correction is smaller than estimated value SOC_e before correction. Further, as the estimated value SOC_e before correction becomes smaller than SOC (0), the estimated value SOC_e ′ after correction is larger than the SOC_e before correction so that the difference (offset amount) from the estimated value SOC_e before correction increases. Is also a small value.

  As a result, since the deterioration of the estimation accuracy is suppressed by the correction in the region close to the lower limit value of the SOC where the estimation accuracy is deteriorated, the actual SOC is suppressed from being lower than the lower limit value.

  Further, in a region where estimated SOC value SOC_e before correction is larger than SOC (1), estimated value SOC_e ′ after correction is larger than estimated value SOC_e before correction. Further, as the estimated value SOC_e before correction becomes larger than the SOC (1), the estimated value SOC_e ′ after correction increases so that the difference (offset amount) from the estimated value SOC_e before correction increases. It becomes a value larger than SOC_e.

  As a result, in the region close to the upper limit value of the SOC where the estimation accuracy deteriorates, the deterioration of the estimation accuracy is suppressed by the correction, so that the actual SOC is suppressed from exceeding the upper limit value.

  As described above, according to vehicle 1 according to the present embodiment, the SOC estimation accuracy based on OCV affects the internal resistance estimation accuracy. Also, the increase in internal resistance caused by the uneven salt concentration of the electrolyte in the electrode plate of the lithium ion battery depends on the integrated value IBs of the current to the lithium ion battery. That is, the correction amount SOC_c is calculated based on the integrated value IBs of the current IB, and the estimated SOC value SOC_e based on the OCV is corrected, thereby suppressing deterioration in the SOC estimation accuracy based on the OCV. Therefore, even when charging / discharging of a large current is continued, and the internal resistance is increased due to deviation in the salt concentration of the electrolytic solution in the electrode plate of the lithium ion battery, the SOC can be estimated with high accuracy. Therefore, it is possible to provide a vehicle control device and a remaining capacity estimation method that suppress deterioration in the estimation accuracy of the remaining capacity of a lithium ion battery when charging and discharging with a large current is continued.

  Furthermore, since the deterioration of the estimation accuracy is suppressed by the correction even in the vicinity of the upper limit value or the lower limit value of the SOC where the estimation accuracy deteriorates, it is possible to suppress the actual SOC from exceeding the upper limit value or the lower limit value. As a result, it is possible to suppress a reduction in the travel distance of the vehicle 1 due to a deterioration in the estimation accuracy of the SOC, completion of charging before full charging, and the like.

  In the present embodiment, the basic value Ba, the first gain Ga, and the second gain Gb are calculated using tables such as those shown in FIGS. 6 to 8. However, for example, a predetermined value is used instead of the table. The basic value Ba, the first gain Ga, and the second gain Gb may be calculated using a function.

  Alternatively, in the present embodiment, ECU 200 has been described as directly calculating correction amount SOC_c from OCV, integrated value IBs, battery temperature TB, or full charge capacity FCC. The amount of increase in internal resistance caused by the deviation of the salt concentration of the electrolyte in the electrode plate of the lithium ion battery may be estimated from the integrated value IBs, the battery temperature TB, or the full charge capacity FCC. ECU 200 may estimate the amount of increase in internal resistance based on at least integrated value IBs. ECU 200 may calculate the OCV from voltage VB in consideration of the estimated increase in internal resistance, and may estimate the SOC from the calculated OCV. Thus, by calculating the estimated value of OCV in consideration of the amount of increase in internal resistance, the estimated value of OCV indicated by the broken line in FIG. 4 can be made closer to the actual OCV indicated by the one-dot chain line in FIG. As a result, the SOC can be estimated with high accuracy.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 vehicle, 2 wheels, 8 speed reducer, 10 transmission, 12 resolver, 16 drive shaft, 22 wheel speed sensor, 24 PCU, 26 battery, 72 battery cell, 78 charging device, 150 start switch, 156 battery temperature sensor, 158 current Sensor, 160 Voltage sensor, 200 ECU, 201 Memory, 202 Integrated value calculation unit, 204 Correction amount calculation unit, 206 SOC determination unit, 300 Charging plug, 302 External power supply, 304 Charging cable.

Claims (11)

A vehicle control device mounted on a vehicle including a drive motor and a lithium ion battery for supplying power to the drive motor,
A detector for detecting the current and voltage of the lithium ion battery;
A correction amount of the remaining capacity of the lithium ion battery is calculated based on the integrated value of the current, and the remaining capacity is estimated based on the calculated correction amount and the estimated value of the remaining capacity based on the voltage And a control unit for
The correction amount is a correction amount of the remaining capacity according to the distribution state of the salt concentration of the electrolytic solution in at least one of the electrode plates and the electrode plate surface in the lithium ion battery,
The control unit multiplies a basic value calculated based on an open circuit voltage of the lithium ion battery and a battery temperature of the lithium ion battery by a first coefficient calculated based on the integrated value and the battery temperature. And calculating the correction amount,
The said control part is a vehicle control apparatus which calculates a said 1st coefficient so that a said 1st coefficient may become large compared with the time when the said integrated value is small when the said integrated value is small.   2. The vehicle control device according to claim 1, wherein the control unit calculates the basic value so that the basic value is larger when the open voltage is large than when the open voltage is small.   2. The vehicle control device according to claim 1, wherein the control unit calculates the basic value so that the basic value is smaller when the battery temperature is high than when the battery temperature is low.   The said control part calculates the said basic value based on the 1st map for calculating the said basic value by using the said open voltage, the said battery temperature, and the said open voltage and the said battery temperature as an argument. The vehicle control device described in 1.   2. The vehicle control device according to claim 1, wherein the control unit calculates the first coefficient when the battery temperature is high so that the first coefficient is smaller than when the battery temperature is low.   The control unit calculates the first coefficient based on a second map for calculating the first coefficient using the integrated value, the battery temperature, and the integrated value and the battery temperature as arguments. Or the vehicle control device according to 5.   The control unit calculates the correction amount by multiplying the basic value by a second coefficient calculated based on an estimated value of a full charge capacity of the lithium ion battery in addition to the first coefficient. The vehicle control device according to claim 1.   The vehicle control according to claim 7, wherein when the full charge capacity is large, the control unit calculates the second coefficient so that the second coefficient is smaller than when the full charge capacity is small. apparatus.   The vehicle control device according to claim 8, wherein the control unit calculates the second coefficient based on a third map for calculating the second coefficient using the full charge capacity and the full charge capacity as arguments. . The lithium ion battery includes a battery cell prismatic, vehicle control device according to any one of claims 1-9. A method for estimating a remaining capacity of a lithium ion battery for supplying power to a drive motor mounted on a vehicle,
Calculating a correction amount of the remaining capacity of the lithium ion battery based on an integrated value of the current of the lithium ion battery;
Estimating the remaining capacity based on the calculated correction amount and an estimated value of the remaining capacity based on the voltage of the lithium ion battery,
The correction amount is a correction amount of the remaining capacity according to the distribution state of the salt concentration of the electrolytic solution in at least one of the electrode plates and the electrode plate surface in the lithium ion battery,
The step of calculating the correction amount includes:
The basic value calculated based on the open voltage of the lithium ion battery and the battery temperature of the lithium ion battery is multiplied by a first coefficient calculated based on the integrated value and the battery temperature, and the correction is performed. Calculating a quantity;
And calculating the first coefficient so that the first coefficient is larger when the integrated value is larger than when the integrated value is small.

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