WO2022009670A1 - Battery control device - Google Patents

Abstract

A battery control device (70) carries out charge control on the basis of a current detected by a current sensor (22) when a battery (21) is charged with power supplied from an external charging device (100). The battery control device is provided with: an acquisition unit that acquires, as output current information, an output current detected by the external charging device when charging the battery by the external charging device; a reliability determination unit that determines the reliability of the output current information; an anomaly determination unit that determines whether or not an anomaly is occurred in the current sensor; and a charge control unit that, when it is determined that an anomaly has occurred in the current sensor and if the reliability determination unit has determined that the output current information is reliable, carries out charge control using the output current information instead of the current detected by the current sensor.

Description

Storage battery control device Cross-reference of related applications

This application is based on Japanese Application No. 2020-119245 filed on July 10, 2020, and the contents of the description are incorporated herein by reference.

The disclosure in this specification relates to a storage battery control device.

Conventionally, as a power supply system having a storage battery, a power system including a current sensor that detects the charging current and the discharging current of the storage battery and a control device that controls charging / discharging of the storage battery based on the detected current detected by the current sensor is known. ing. For example, in the technique described in Patent Document 1, a failure detection unit that detects a failure of a voltage detection device that detects the voltage of a storage battery and a contactor that controls opening and closing of a contactor provided on a power supply line through which a discharge current and a charge current flow. A control unit is provided, and when a failure of the voltage detection device is detected, the actual charge current amount obtained by integrating the charge current and the discharge current and subtracting the integrated value of the discharge current from the integrated value of the charge current is a predetermined value. When the above is reached, the contactor is controlled to be open and charging / discharging from the storage battery is prohibited.

Japanese Unexamined Patent Publication No. 2017-73892

By the way, in an electric vehicle or a hybrid vehicle, the vehicle and the external charging device are connected by a charging cable or the like, and the storage battery is charged from the power supplied from the external charging device. In this case, in the power supply system on the vehicle side, charging control of the storage battery is performed while detecting the current flowing from the external charging device side to the storage battery by the current sensor. However, if an abnormality occurs in the current sensor, it becomes impossible to detect the current flowing through the storage battery from the external charging device side, so that it is considered difficult to properly charge the storage battery.

The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a storage battery control device capable of appropriately performing charge control even when an abnormality of the current sensor occurs.

Means 1
The storage battery is provided with a storage battery and a current sensor for detecting the current flowing through the storage battery, and is applied to a power supply system capable of charging the storage battery by supplying power from an external charging device. It is a storage battery control device that performs charge control based on the detection current of the current sensor at the time of charging.
An acquisition unit that acquires the output current detected by the external charging device as output current information when the storage battery is charged by the external charging device.
A reliability determination unit that determines the reliability of the output current information,
An abnormality determination unit that determines whether or not an abnormality has occurred in the current sensor,
When it is determined that an abnormality has occurred in the current sensor, the reliability determination unit determines that the output current information is reliable, and the current is replaced with the current detected by the current sensor. A charge control unit that performs charge control using output current information,
To prepare for.

When charging the storage battery by supplying power from the external charging device, a current flows from the external charging device side to the storage battery via a charging cable or the like, and at that time, charging control is performed based on the detection current of the current sensor. Will be done. In this case, if an abnormality occurs in the current sensor, charge control based on the detected current of the current sensor cannot be performed.

In this regard, in the above configuration, when the storage battery is charged by the external charging device, the output current detected by the external charging device is acquired as the output current information, and the reliability of the output current information is determined. Then, when it is determined that an abnormality has occurred in the current sensor, charge control is performed using the output current information instead of the detected current of the current sensor, provided that the output current information is determined to be reliable. I tried to carry out. In this case, even if the reliability of the output current information transmitted from the external charging device is unknown, it is properly determined whether or not the output current information can be used for charging control instead of the detected current of the current sensor. It is possible to make a judgment, and it is possible to carry out charge control using output current information. From the vehicle side, it is possible that the specifications and accuracy of the current detector provided on the external charging device side are unknown, but according to the above configuration, the output current information from the external charging device should be used appropriately. Can be done. As a result, the charge control can be properly performed even when the current sensor is abnormal.

In the means 2, in the means 1, the reliability determination unit acquires the terminal voltage and the internal resistance of the storage battery when the storage battery is charged by the external charging device, and is obtained from the terminal voltage and the internal resistance. The reliability of the output current information is determined by comparing the current estimated value of the storage battery with the output current information.

When the storage battery is energized, the current estimated value of the storage battery can be calculated based on the terminal voltage of the storage battery and the internal resistance, and the output current information is reliable by comparing the current estimated value with the output current information. It is possible to determine whether or not it is. As a result, it is possible to suitably perform reliability determination of the output current information received from the external charging device, and to appropriately perform charging control in the event of an abnormality of the current sensor.

A power supply system including a storage battery generally has a voltage sensor in addition to the current sensor, and the terminal voltage of the storage battery can be detected by the voltage sensor. For example, the value of the internal resistance of the storage battery must be acquired in advance. Therefore, using Ohm's law, it is possible to calculate the current estimated value of the storage battery from the terminal voltage and internal resistance of the storage battery.

In the means 3, in the means 1 or 2, the reliability determination unit acquires the calorific value and the internal resistance of the storage battery when the storage battery is charged by the external charging device, and obtains the calorific value and the internal resistance from the calorific value and the internal resistance. The reliability of the output current information is determined by comparing the current estimated value of the storage battery and the output current information.

When the storage battery is energized, the current estimated value of the storage battery can be calculated based on the calorific value of the storage battery and the internal resistance, and the output current information is reliable by comparing the current estimated value with the output current information. It is possible to determine whether or not it is. As a result, it is possible to suitably perform reliability determination of the output current information received from the external charging device, and to appropriately perform charging control in the event of an abnormality of the current sensor.

A power supply system including a storage battery generally has a temperature sensor that detects the temperature of the storage battery in addition to the current sensor, and the temperature sensor obtains the amount of temperature change that occurs when the storage battery is energized, and the temperature change amount and the storage battery. The calorific value of the storage battery can be obtained from the heat capacity of. Further, using Joule's law, it is possible to calculate the current estimated value of the storage battery from the calorific value of the storage battery and the internal resistance.

In the means 4, in any of the means 1 to 3, the reliability determination unit acquires the open circuit voltage of the storage battery before and after the predetermined energization time when the storage battery is charged by the external charging device, and the open circuit voltage thereof. The reliability of the output current information is determined by comparing the current estimated value of the storage battery obtained from the SOC change amount of the storage battery corresponding to the change of the above with the output current information.

While there is a correlation between the amount of change in the open circuit voltage of the storage battery that occurs before and after the predetermined energization time and the amount of change in the SOC of the storage battery when the storage battery is energized, the amount of SOC change is obtained by integrating the charge / discharge current in the storage battery. Can be done. Therefore, the SOC change amount can be obtained from the open circuit voltage of the storage battery before and after the predetermined energization time, and the current estimated value of the storage battery can be calculated from the SOC change amount. Then, by comparing the current estimated value with the output current information, it is possible to determine whether or not the output current information has reliability. As a result, it is possible to suitably perform reliability determination of the output current information received from the external charging device, and to appropriately perform charging control in the event of an abnormality of the current sensor.

In the means 5, when it is determined in any of the means 2 to 4 that no abnormality has occurred in the current sensor, the difference between the detected current of the current sensor and the estimated current value is stored as a learning value. The reliability determination unit corrects the current estimated value by the learned value, and determines the reliability of the output current information using the corrected current estimated value.

Due to deterioration of the storage battery and individual differences, the accuracy of the current estimation value calculated based on the terminal voltage and internal resistance of the storage battery, the calorific value of the storage battery, the internal resistance, etc. may be affected, and the current estimation value may be affected. If the accuracy of the output current is lowered, there is a concern that the reliability determination of the output current information may be affected. In this regard, in the above configuration, when the current sensor is normal, the difference between the detected current of the current sensor and the estimated current value is stored as a learning value, and the estimated current value is learned when determining the reliability of the output current information. It was corrected by the value, and the reliability of the output current information was judged using the corrected current estimated value. This makes it possible to improve the accuracy of the reliability determination of the output current information.

In the means 6, in any of the means 1 to 5, the storage battery control device determines that the charging is completed based on the fact that the current flowing through the storage battery drops to a predetermined value when the storage battery is charged by the external charging device. Therefore, when the charge control unit executes the charge control based on the output current information, the charge control is executed so that the end of charging is accelerated as compared with the case where the charge control is executed based on the current sensor. Change the aspect.

As mentioned above, from the vehicle side, it is considered that the specifications and accuracy of the current detection unit provided on the external charging device side are unknown, and the accuracy of the current detection unit is assumed to be higher than the accuracy of the current sensor on the power supply system side. If it is low, there is a concern that the storage battery will be overcharged. In this respect, when the charge control is performed based on the output current information, the embodiment of the charge control is changed so that the charge end is accelerated as compared with the case where the charge control is performed based on the current sensor. As a result, charge control based on output current information can be properly performed.

In the means 7, in any of the means 1 to 6, the reliability determination unit calculates the degree of reliability when it is determined that the output current information is reliable, and the charging The control unit changes the embodiment of the charge control performed based on the output current information according to the degree of reliability of the output current information.

It is conceivable that the degree of reliability of the output current information transmitted from the external charging device varies even if it is determined to be reliable. Further, it is considered that the degree of error included in the output current information changes depending on the degree of reliability. In this regard, by changing the mode of charge control performed based on the output current information according to the degree of reliability of the output current information, appropriate charge control according to the degree of error included in the output current information is performed. Can be carried out.

In the means 8, in any of the means 1 to 7, the reliability determination unit has a plurality of determination processes as reliability determination processes for determining the reliability of the output current information, and each of these determination processes is performed. When the storage battery is charged by the external charging device, different parameters are acquired and the reliability of the output current information is determined using the parameters, and the charge control unit is based on the output current information. The embodiment of the charge control to be performed is changed depending on which of the plurality of determination processes determines that the output current information is reliable.

When determining the reliability of the output current information from the external charging device, for example, the reliability may be determined using the terminal voltage and internal resistance of the storage battery as parameters, or the calorific value and internal resistance may be used as parameters. It is possible to judge the reliability by using the open circuit voltage before and after the energization of the storage battery as a parameter. In this case, it is considered that the degree of reliability of the output current information, in other words, the degree of error included in the output current information, changes depending on which of these plurality of determination processes determines that the reliability is present. In this regard, by changing the embodiment of the charge control performed based on the output current information according to which of the plurality of determination processes it is determined that the output current information is reliable, the output current information can be obtained. Appropriate charge control can be performed according to the degree of error included.

The above objectives and other objectives, features and advantages of the present disclosure will be further clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a configuration diagram showing a vehicle power supply system. FIG. 2 is a time chart for explaining CC charging and CV charging. FIG. 3 is a flowchart showing the processing procedure of charge control. FIG. 4 is a flowchart showing the reliability determination process of the output current information. FIG. 5 is a flowchart showing the reliability determination process of the output current information. FIG. 6 is a flowchart showing the reliability determination process of the output current information. FIG. 7 is a diagram showing the relationship between the OCV and SOC of the battery. 8A and 8B are diagrams showing the relationship between the current difference and the reliability degree, and FIG. 8B is a diagram showing the relationship between the reliability degree and the current threshold value. FIG. 9 is a flowchart showing a charge control processing procedure according to the third embodiment. FIG. 10 is a flowchart showing a learning process for learning the difference between the estimated current values. FIG. 11 is a diagram showing the relationship between the output current of the external charging device and the estimated current value.

(First Embodiment)
Hereinafter, embodiments will be described with reference to the drawings. This embodiment is applied to an electric vehicle having a motor as a traveling power source, and first, an outline of a power supply system for the electric vehicle will be described with reference to FIG.

In FIG. 1, the vehicle 10 includes a main battery 21, an inverter 30 that converts DC power of the main battery 21 into AC power, and a motor 40 as an electric load driven by AC power output from the inverter 30. ing. When the vehicle 10 is running, electric power is supplied from the main battery 21 to the motor 40 via the inverter 30 in response to the accelerator operation by the driver, and the running power is given to the vehicle 10 by the power running drive of the motor 40 accompanying the power supply. Will be done. The motor 40 is a rotary electric machine (motor generator) having a power generation function in addition to the power running function. For example, when the vehicle 10 is decelerated, the generated power generated by the regenerative power generation is supplied to the main battery 21 via the inverter 30. In this case, the motor 40 functions as a generator, and the main battery 21 is charged by the generated power. In this embodiment, the main battery 21 corresponds to a "storage battery".

The main battery 21 is a storage battery that can be charged and discharged, and is an assembled battery in which a plurality of battery cells are connected in series. The main battery 21 is, for example, a lithium ion storage battery having an output voltage of about several hundred V. The main battery 21 is provided as a battery unit 20 together with various sensors, and the battery unit 20 includes current sensors 22 and 23 for detecting the current input to / from the main battery 21 and a voltage for detecting the terminal voltage of the main battery 21. It includes a sensor 24 and a temperature sensor 25 that detects the temperature of the main battery 21.

Further, the auxiliary battery 60 is connected to the main battery 21 via a DCDC converter 50 as a power converter. The auxiliary battery 60 is a battery having a lower rated voltage than the main battery 21, and is, for example, a lead storage battery having an output voltage of about 12 V. The DCDC converter 50 steps down the high voltage of the main battery 21 to the voltage level of the auxiliary battery 60 to supply electric power to the auxiliary battery 60.

Further, the main battery 21 can be charged by the electric power supplied from the external charging device 100. The external charging device 100 is, for example, a charger installed in a charging stand or the like, and by being connected to the vehicle 10 by a charging cable, the external charging device 100 can charge the main battery 21. The external charging device 100 is configured to be capable of outputting electric power at a constant current, outputting electric power at a constant voltage, and outputting electric power at a constant voltage and constant current.

Further, the vehicle 10 includes a battery control device 70 mainly composed of a microcomputer having a CPU and various memories, and a motor control device 80. The battery control device 70 and the motor control device 80 are connected by a communication network such as CAN so that they can communicate with each other. Further, the battery control device 70 and the external charging device 100 can communicate with each other through a charging cable at the time of external charging or via a communication means such as a wireless LAN.

Each of these control devices 70 and 80 appropriately uses the detection information detected by various sensors of the battery unit 20 to control the charging / discharging of the main battery 21 and the driving of the motor 40. Here, among the various sensors of the battery unit 20, the current sensors 22 and 23 have different detection ranges, one of the current sensors 22 has a current detection range defined as the first range, and the other current sensor 23 has a first range. , The current detection range is defined as a second range wider than the first range. In this case, the battery control device 70 implements charge control at the time of battery charging by the external charging device 100 based on the detected current of the current sensor 22. Further, the motor control device 80 performs traveling control by driving the motor 40 based on the detected current of the current sensor 23. In the following description, the current sensor 22 will be referred to as a first current sensor 22, and the current sensor 23 will be referred to as a second current sensor 23.

Supplement for each current sensor 22 and 23. Since the first current sensor 22 has a narrower current detection range than the second current sensor 23, the detection resolution is high and the error is small. To put it the other way around, the second current sensor 23 has a wider current detection range than the first current sensor 22, so that the detection resolution is low and the error is large.

The battery control device 70 charges the main battery 21 by the CC-CV charging method at the time of external charging by the external charging device 100. CC charging is constant current charging that charges the main battery 21 with the output current of the external charging device 100 set to a constant value, and CV charging is charging the main battery 21 with the charging voltage of the external charging device 100 set to a constant value. It is a constant voltage charge. The CC-CV charging method will be described with reference to FIG. FIG. 2 shows the transition of the terminal voltage of the main battery 21 and the transition of the charging current flowing through the main battery 21 after the start of external charging.

In FIG. 2, CC charging is performed so that the charging current is a constant value from the start of charging to the timing t11. During the CC charging period, the terminal voltage of the main battery 21 gradually increases with the passage of time. During the CC charging period, a predetermined target current is set in the battery control device 70, and the output current of the external charging device 100 is set so that the actual current flowing through the main battery 21 (detected current of the first current sensor 22) matches the target current. Control should be implemented.

Then, at the timing t11, when the switching condition from CC charging to CV charging is satisfied, switching from CC charging to CV charging is performed. For example, it is preferable to use the terminal voltage of the main battery 21 as a parameter for charge switching, and switch from CC charging to CV charging based on the terminal voltage reaching a predetermined voltage Vth. After the timing t11, the external charging device 100 is instructed by the battery control device 70 to charge the target voltage. It should be noted that the configuration may be such that switching from CC charging to CV charging is performed after a predetermined time has elapsed after the start of CC charging.

After timing t11, CV charging is performed to keep the charging voltage at a constant value. During the CV charging period, the charging current of the main battery 21 gradually decreases with the passage of time. Then, at the timing t12, when the charging current of the main battery 21 drops to a predetermined current threshold value Is (cutoff current), charging is terminated. At this time, the battery control device 70 determines that charging is completed based on the fact that the detected current of the first current sensor 22 drops to the current threshold value Is.

At the time of external charging, the output current detected by the external charging device 100 may be transmitted to the battery control device 70 as output current information. For example, the external charging device 100 detects the output current output from the external charging device 100 by a current detecting means such as a current sensor included in the external charging device 100 itself, and transmits the current information to the battery control device 70. .. The battery control device 70 compares the output current information from the external charging device 100 with the detected current of the first current sensor 22 at the time of external charging, and if there is a difference between them, corrects the output current to the external charging device 100. Give instructions. For example, if the output current is 100 amps and the detection current of the first current sensor 22 is 95 amps according to the external information transmitted from the external charging device 100, the battery control device 70 makes a difference to the external charging device 100. Instruct to increase the output current by 5 amperes.

By the way, if an abnormality occurs in the first current sensor 22 during external charging in which the main battery 21 is charged by supplying power from the external charging device 100, charging control by the detected current of the first current sensor 22 cannot be performed.

Therefore, in the present embodiment, the battery control device 70 acquires the output current detected by the external charging device 100 as output current information when the main battery 21 is charged by the external charging device 100, and the output current information thereof. When it is determined that an abnormality has occurred in the first current sensor 22, the reliability determination unit for determining the reliability of the first current sensor 22, and the abnormality determination unit for determining whether or not an abnormality has occurred in the first current sensor 22. On the condition that the reliability determination unit determines that the output current information is reliable, the charge control unit performs charge control using the output current information instead of the detection current of the first current sensor 22. It is configured to be equipped with.

FIG. 3 is a flowchart showing a processing procedure of charge control at the time of battery charging by the external charging device 100, and this processing is performed under the condition that the IG switch is off and the external charging request of the main battery 21 is generated. It is carried out by the battery control device 70 at a predetermined cycle.

In FIG. 3, in step S11, it is determined whether or not the main battery 21 is being charged by the external charging device 100. At this time, for example, it is determined whether or not the battery control device 70 can communicate with the external charging device 100 while the charging cable is connected. Then, when step S11 is affirmed, the process proceeds to the subsequent step S12. In step S12, the output current information transmitted from the external charging device 100 is acquired after the start of external charging.

After that, in step S13, it is determined whether or not the first current sensor 22 is normal. The abnormality determination method of the first current sensor 22 may be arbitrary. For example, when the detection current of the first current sensor 22 remains zero or remains at the maximum detection value, it means that an abnormality has occurred. It is judged. The abnormality determination process of the first current sensor 22 is performed while the IG switch is on and during external charging, and the abnormality determination result is stored and held in a backup memory such as a backup RAM or EEPROM.

If the first current sensor 22 is normal, the process proceeds to step S14. In step S14, charge control is performed using the detected current of the first current sensor 22. In this case, the battery control device 70 charges the main battery 21 by the CC-CV charging method as described above. That is, the battery control device 70 tells the external charging device 100 that CC charging that makes the output current a constant value is performed during the period from the start of charging until the terminal voltage of the main battery 21 reaches a predetermined voltage Vth. Command. Further, when the terminal voltage of the main battery 21 reaches a predetermined voltage Vth, the external charging device 100 is instructed to perform CV charging to keep the charging voltage at a constant value thereafter. Then, when the charging current of the main battery 21 drops to the current threshold value Is1, charging ends. In the CC charging period, the output current information from the external charging device 100 and the detected current of the first current sensor 22 are compared, and the output current of the external charging device 100 may be corrected according to the difference between them.

If the first current sensor 22 is abnormal, the process proceeds to step S15. In step S15, the reliability determination process is performed to determine the reliability of the output current information. FIG. 4 shows the reliability determination process.

In FIG. 4, in step S21, the terminal voltage and the internal resistance of the main battery 21 are acquired. At this time, the detected voltage detected by the voltage sensor 24 is acquired as the terminal voltage of the main battery 21. Further, the internal resistance of the main battery 21 calculated before the external charging this time is acquired as the internal resistance of the current main battery 21. The internal resistance of the main battery 21 may be the internal resistance calculated under the IG on state before the current external charge, or the internal resistance calculated at the time of the external charge before the current external charge. It may be resistance. Alternatively, the internal resistance of the main battery 21 may be a conforming value.

Further, in step S22, using Ohm's law, the energization current flowing through the main battery 21 during external charging is calculated as a current estimated value based on the terminal voltage and the internal resistance of the main battery 21.

After that, in step S23, the reliability of the output current information is determined by comparing the current estimated value of the main battery 21 calculated in step S22 with the output current information (output current information acquired in step S12 of FIG. 3). .. The output current information may be the detected current in the external charging device 100 during CC charging. At this time, the battery control device 70 calculates the difference between the current estimated value of the main battery 21 and the current detection value of the external charging device 100 as the output current information, and if the difference is less than a predetermined value, the output is output. It is assumed that the current information is reliable, and if the difference is equal to or greater than a predetermined value, the output current information is not reliable.

Returning to the description of FIG. 3, in step S16, it is determined whether or not the result of the reliability determination of the output current information performed in step S15 is reliable. Then, if there is reliability, the process proceeds to step S17, and if there is no reliability, the process proceeds to step S19.

In step S17, when the charge control is executed based on the output current information, the embodiment of the charge control is changed so that the end of charging is earlier than the case where the charge control is executed based on the first current sensor 22. .. Specifically, the current threshold value Is (see FIG. 2) used for determining the completion of charging is changed to the current threshold value Is2, which is larger than the current threshold value Is1 used in step S14.

In the following step S18, charge control is performed based on the output current information. In this case, since the current threshold value Is2 is used instead of the current threshold value Is1 in the charge completion determination, charging is completed earlier than the normal charge control using the detected current of the first current sensor 22.

If it is determined in step S16 that there is no reliability, the process proceeds to step S19. In step S19, it is determined to stop the implementation of the external charge. In this case, it is advisable to notify the user that external charging cannot be performed.

As the reliability determination process in step S15, the reliability determination process shown in FIGS. 5 and 6 can be performed instead of the reliability determination process shown in FIG.

In the reliability determination process of FIG. 5, in step S31, the calorific value and the internal resistance of the main battery 21 are acquired. At this time, the temperature sensor 25 calculates the amount of temperature change caused by energization of the main battery 21, and the calorific value of the main battery 21 is calculated from the amount of the temperature change and the heat capacity of the main battery 21. Further, the internal resistance of the main battery 21 may be acquired by the same method as in step S21 of FIG.

Further, in step S32, Joule's law is used to calculate the energization current flowing through the main battery 21 at the time of external charging as a current estimated value based on the calorific value of the main battery 21 and the internal resistance. Specifically, the current I is calculated from the calorific value Q and the internal resistance R using the relationship of "Q = I ^ 2 · R · t".

After that, in step S33, the reliability of the output current information is determined by comparing the current estimated value of the main battery 21 calculated in step S32 with the output current information. This process is the same as step S23 in FIG. When calculating the estimated current value of the main battery 21 from the calorific value of the main battery 21, the external charging device 100 is instructed to set the output current to a constant value, and the constant current output is used. The reliability of the output current information may be determined by comparing the current estimated value of the main battery 21 with the output current information.

Further, in the reliability determination process of FIG. 6, in step S41, the open circuit voltage OCV of the main battery 21 before and after the predetermined energization time is acquired, and the voltage change amount is used by using the correlation between the open circuit voltage OCV and the SOC. The SOC change amount ΔSOC corresponding to the change of ΔOCV is calculated. At this time, the detection voltages V1 and V2 of the voltage sensor 24 are acquired before and after the predetermined energization time, and the SOC change amount ΔSOC is calculated from the detected voltages V1 and V2, respectively. More specifically, for example, using the correlation of FIG. 7, X1 and X2 may be calculated as SOC from the detected voltages V1 and V2, and further, the SOC change amount ΔSOC may be calculated from these X1 and X2.

Further, in step S42, since the SOC change amount ΔSOC can be calculated by integrating the charge / discharge current in the main battery 21, the energization current flowing through the main battery 21 during external charging is calculated as the current estimated value based on the SOC change amount ΔSOC. .. Specifically, the current I is calculated using the relationship of "ΔSOC = ΣI".

After that, in step S43, the reliability of the output current information is determined by comparing the current estimated value of the main battery 21 calculated in step S42 with the output current information. This process is the same as step S23 in FIG. When calculating the current estimated value of the main battery 21 from the open circuit voltage OCV of the main battery 21 before and after the predetermined energization time, the external charging device 100 is instructed to set the output current to a constant value. In the state of constant current output, the reliability of the output current information may be determined by comparing the current estimated value of the main battery 21 with the output current information.

In addition, although three reliability determination processes are exemplified in this embodiment, it is possible to carry out any two or three of them together, in addition to being able to carry out only one of them. Is. When a plurality of reliability determination processes are performed, it is finally determined that the output current information is reliable based on the fact that all of the reliability determination processes determine that the output current information is reliable. It is advisable to configure it in such a way.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

When it is determined that an abnormality has occurred in the first current sensor 22 when the main battery 21 is being charged by the external charging device 100, it is determined that the output current information transmitted from the external charging device 100 is reliable. On the condition that this is the case, the charge control is performed by using the output current information instead of the detected current of the first current sensor 22. In this case, even if the reliability of the output current information transmitted from the external charging device 100 is unknown, whether or not the output current information can be used for charging control instead of the detected current of the first current sensor 22. It is possible to properly determine whether or not the charge is controlled using the output current information. From the vehicle 10 side, it is possible that the specifications and accuracy of the current detection unit provided on the external charging device 100 side are unknown, but according to the above configuration, the output current information from the external charging device 100 is appropriate. Can be used for. As a result, the charge control can be properly performed even when the first current sensor 22 is abnormal.

When the main battery 21 is energized, the current estimated value of the main battery 21 can be calculated based on the terminal voltage of the main battery 21 and the internal resistance, and the output current information is compared with the current estimated value and the output current information. It is possible to determine whether or not the battery has reliability. This makes it possible to preferably determine the reliability of the output current information received from the external charging device 100.

When the main battery 21 is energized, the current estimated value of the main battery 21 can be calculated based on the calorific value of the main battery 21 and the internal resistance, and the output current information is compared with the current estimated value and the output current information. It is possible to determine whether or not the battery has reliability. This makes it possible to preferably determine the reliability of the output current information received from the external charging device 100.

While there is a correlation between the amount of change in the open circuit voltage of the main battery 21 that occurs before and after the predetermined energization time and the amount of change in the SOC of the main battery 21 when the main battery 21 is energized, the charge / discharge current of the main battery 21 The amount of SOC change can be obtained by integration. Therefore, the SOC change amount can be obtained from the open circuit voltage of the main battery 21 before and after the predetermined energization time, and the current estimated value of the main battery 21 can be calculated from the SOC change amount. Then, by comparing the current estimated value with the output current information, it is possible to determine whether or not the output current information has reliability. This makes it possible to preferably determine the reliability of the output current information received from the external charging device 100.

From the vehicle 10 side, it is considered that the specifications and accuracy of the current detection unit provided on the external charging device 100 side are unknown, and if the accuracy of the current detection unit is lower than the accuracy of the current sensor on the power supply system side. For example, there is a concern that the main battery 21 may be overcharged. In this regard, when the charge control is performed based on the output current information, the embodiment of the charge control is changed so that the charge end is accelerated as compared with the case where the charge control is performed based on the first current sensor 22. I made it. As a result, charge control based on output current information can be properly performed.

Next, another embodiment in which a part of the first embodiment is modified will be described. In the following description, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

(Second Embodiment)
In the second embodiment, when it is determined that the output current information transmitted from the external charging device 100 is reliable, the degree of reliability is calculated, and the degree of reliability is calculated according to the degree of reliability of the output current information. The embodiment of the charge control performed based on the output current information will be changed.

Specifically, for example, in step S23 of FIG. 4, the current difference ΔI between the current estimated value of the main battery 21 calculated in step S22 and the current detected by the external charging device 100 as output current information is calculated. Further, for example, using the relationship shown in FIG. 8A, the reliability of the output current information is calculated based on the current difference ΔI. Here, a large current difference ΔI means that an error included in the output current information is large, and it is said that the larger the current difference ΔI, the smaller the degree of reliability. Incidentally, in FIG. 8A, if the current difference ΔI is Y or more, it is determined that the output current information is unreliable.

The reliability may be calculated in multiple steps. For example, if the current difference ΔI is larger than the predetermined value (predetermined value <Y), the reliability is low, and if the current difference ΔI is smaller than the predetermined value, the reliability is reduced. It may be configured to have a high degree of sex.

Further, in step S17 of FIG. 3, for example, using the relationship of FIG. 8B, the current threshold value Is2 used for the charge completion determination is set based on the reliability of the output current information. In this case, the current threshold value Is2 is set as a value larger than the current threshold value Isth1 used when the sensor is normal, and is set as a smaller value as the reliability of the output current information is larger.

It is conceivable that the degree of reliability of the output current information transmitted from the external charging device 100 varies even if it is determined to be reliable. Further, it is considered that the degree of error included in the output current information changes depending on the degree of reliability. In this regard, since the embodiment of the charge control performed based on the output current information is changed according to the reliability of the output current information, the appropriate charge control according to the degree of error included in the output current information is changed. Can be carried out.

Note that the current target value at the time of CC charging may be changed according to the reliability of the output current information. For example, when the reliability of the output current information is low, the current target value may be set to a lower value than when the reliability of the output current information is high.

(Third Embodiment)
In the third embodiment, a plurality of determination processes are included as reliability determination processes for determining the reliability of the output current information, and each of these determination processes sets different parameters during external charging by the external charging device 100. The reliability of the output current information is judged by acquiring and using the parameters. Then, the embodiment of the charge control performed based on the output current information is changed depending on which of the plurality of determination processes determines that the output current information is reliable.

FIG. 9 is a flowchart showing the processing procedure of charge control in the present embodiment, and this processing is carried out in place of the processing of FIG. 3 described above. In FIG. 9, the same process as in FIG. 3 is assigned the same step number, and the description thereof will be omitted.

In FIG. 9, when it is determined in step S13 that the first current sensor 22 is abnormal, the process proceeds to step S51. In step S51, as the reliability determination process, the first determination process with the terminal voltage of the main battery 21 and the internal resistance as parameters is performed. This first determination process is the reliability determination process described with reference to FIG. 4, in which the terminal voltage and internal resistance of the main battery 21 are acquired, and the current estimated value of the main battery 21 obtained from the terminal voltage and the internal resistance is obtained. And the output current information are compared to determine the reliability of the output current information.

After that, in step S52, it is determined whether or not the determination result of the first determination process performed in step S51 is reliable. Then, if there is reliability, the process proceeds to step S53, and the control mode of the charge control is changed based on the reliability determination result in the first determination process. At this time, the current threshold value Is used for determining the completion of charging is changed to the current threshold value Is11 larger than the current threshold value Is1 (current threshold value at the normal time) used in step S14. After that, the process proceeds to step S18, and charge control is performed based on the output current information.

Further, if it is determined in step S52 that there is no reliability, the process proceeds to step S54. In step S54, as the reliability determination process, a second determination process using the calorific value of the main battery 21 and the internal resistance as parameters is performed. This second determination process is the reliability determination process described with reference to FIG. 5, in which the calorific value and internal resistance of the main battery 21 are acquired, and the current estimated value of the main battery 21 obtained from the calorific value and the internal resistance is obtained. And the output current information are compared to determine the reliability of the output current information.

After that, in step S55, it is determined whether or not the determination result of the second determination process performed in step S54 is reliable. Then, if there is reliability, the process proceeds to step S56, and the control mode of the charge control is changed based on the reliability determination result in the second determination process. At this time, the current threshold value Is used for determining the completion of charging is changed to the current threshold value Is12 larger than the current threshold value Is1 (current threshold value at the normal time) used in step S14. After that, the process proceeds to step S18, and charge control is performed based on the output current information. If it is determined in steps S52 and S55 that there is no reliability, the process proceeds to step S19, and it is determined to stop the execution of external charging.

Here, the current thresholds Is11 and It12 set in steps S53 and S56 are different values from each other, for example, Is11 <Its12. The difference between the current threshold values Is11 and Is12 depends on which reliability determination process determines that the output current information is reliable, and the certainty of the reliability determination in each reliability determination process. It is good if it corresponds. In the present embodiment, when it is determined to be reliable in the first determination process, the reliability of the output current information is higher than in the case where it is determined to be reliable in the second determination process, and the output current information is used. The degree of error included is small. Therefore, the higher the reliability of the output current information, the smaller the current threshold value is set.

In the present embodiment, the embodiment of the charge control performed based on the output current information is changed according to which of the plurality of determination processes determines that the output current information is reliable, thereby changing the output current. Appropriate charge control can be performed according to the degree of error included in the information.

The reliability determination process includes a first determination process (see FIG. 4) in which the terminal voltage and internal resistance of the main battery 21 are used as parameters, and a second determination process in which the calorific value and internal resistance of the main battery 21 are used as parameters. In addition to the determination process (see FIG. 5), there is a determination process (see FIG. 6) in which the open circuit voltage of the main battery 21 before and after the predetermined energization time is used as a parameter, and the reliability of the output current information is obtained by combining at least two of these. It may be configured to carry out the determination. In this case, if the current threshold value Is13 when it is determined that the output current information is reliable by the determination process using the open circuit voltage of the main battery 21 as a parameter before and after the predetermined energization time, each current threshold value Is11 to It is preferable that Is13 has a relationship of, for example, Is11 <Its12 <Its13.

(Other embodiments)
The above embodiment may be changed as follows, for example.

-In the above embodiment, the output current information from the external charging device 100 is reliable, and when charging control is performed using the output current information instead of the detection current of the first current sensor 22, the output current information is used. Although the charge completion determination was performed based on the above, another process may be performed as charge control using the output current information. For example, when CC charging is performed during external charging by the external charging device 100, charging control is performed so that the charging current to the main battery 21 becomes a constant value based on the output current information.

When the charge completion determination is performed based on the output current information, the detection current on the external charging device 100 side, which is the output current information, is equal to or less than the current threshold Is2, and the predetermined time after starting the CV charging. It may be determined that charging is completed based on the earlier of the elapses. Also in this configuration, it is possible to properly perform the charge completion determination based on the output current information.

Further, when the charge control is performed based on the output current information, the external charging by the external charging device 100 may be terminated when the CC charging is completed.

-In the above embodiment, for example, in FIG. 3, when the first current sensor 22 is determined to be abnormal, the reliability of the output current information is determined. Instead of this, for example, external charging is performed. The reliability of the output current information may be determined before the start of external charging by the device 100. For example, the battery control device 70 transmits a command to the external charging device 100 to perform pre-energization with the output current set to a predetermined value, and acquires output current information at the time of pre-energization. Then, it is determined whether or not the output current information is reliable.

-Due to deterioration and individual differences of the main battery 21, the accuracy of the current estimation value calculated based on the terminal voltage and internal resistance of the main battery 21, the calorific value of the main battery 21, the internal resistance, etc. is affected. If the accuracy of the current estimation value is lowered, there is a concern that the reliability determination of the output current information may be affected. Therefore, when the first current sensor 22 is normal, the difference between the detected current of the first current sensor 22 and the estimated current value of the main battery 21 is calculated, and the difference is stored in the backup memory as a learning value. It may be configured.

FIG. 10 is a flowchart showing a learning process for learning the difference between the estimated current values. In this process, the battery is charged at a predetermined cycle under the condition that the IG switch is off and the external charge request of the main battery 21 is generated. It is carried out by the control device 70.

In FIG. 10, in step S61, it is determined whether or not the first current sensor 22 is normal. Then, when the first current sensor 22 is normal, the process proceeds to the subsequent step S62 to acquire the detected current of the first current sensor 22.

After that, in step S63, the current estimated value of the main battery 21 is calculated. At this time, for example, the terminal voltage and the internal resistance of the main battery 21 are acquired as calculation parameters, and the current estimated value is calculated based on the calculation parameters. Alternatively, the current estimated value is calculated based on the calorific value and internal resistance of the main battery 21 and the open circuit voltage of the main battery 21 before and after the predetermined energization time.

After that, in step S64, the difference between the detected current of the first current sensor 22 and the estimated current value of the main battery 21 is calculated, and in the following step S65, the difference is used as a learning value and used as a backup memory such as a backup RAM or EEPROM. Remember.

This learning value is used, for example, in the reliability determination in step S23 of FIG. That is, in step S23 of FIG. 4, the current estimated value of the main battery 21 is corrected by the learning value, and the reliability of the output current information is determined by comparing the corrected current estimated value with the output current information. According to this embodiment, the accuracy of reliability determination of output current information can be improved.

-In the reliability determination process of the output current information, the output current is instructed from the battery control device 70 to the external charging device 100 with a plurality of currents, and the output current information is acquired for each of the plurality of currents, and each of them is obtained. The configuration may be such that the presence or absence of reliability of the output current information is determined based on the output current information. In this case, the accuracy of reliability determination of the output current information can be improved.

More specifically, as shown in FIG. 11, the battery control device 70 calculates current estimates corresponding to a plurality of (for example, three) output current information. The method for calculating the estimated current value is as described above, and it is preferable that the estimated current value is calculated based on the terminal voltage and internal resistance of the main battery 21, the calorific value and internal resistance of the main battery 21, and the like. .. Then, the approximate straight line L1 is calculated from the plurality of output current information and the estimated current value, and the reliability of the output current information is determined based on the deviation between the approximate straight line L1 and the reference straight line L2. In addition, in the comparison between the approximate straight line L1 and the reference straight line L2, the offset deviation and the gain deviation may be determined respectively.

-In the above embodiment, the present disclosure is applied to the power supply system of the vehicle, but it can also be applied to the power supply system other than the vehicle.

The controls and methods thereof described in the present disclosure are realized by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. May be done. Alternatively, the control unit and method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. It may be realized by one or more dedicated computers configured. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

Although the present disclosure has been described in accordance with the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various variations and variations within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are within the scope and scope of the present disclosure.

Claims (8)

It is applied to a power supply system having a storage battery (21) and a current sensor (22) for detecting the current flowing through the storage battery, and capable of charging the storage battery by supplying power from an external charging device (100). A storage battery control device (70) that performs charge control based on the detection current of the current sensor when the storage battery is charged by power supply from the charging device.
An acquisition unit that acquires the output current detected by the external charging device as output current information when the storage battery is charged by the external charging device.
A reliability determination unit that determines the reliability of the output current information,
An abnormality determination unit that determines whether or not an abnormality has occurred in the current sensor,
When it is determined that an abnormality has occurred in the current sensor, the reliability determination unit determines that the output current information is reliable, and the current is replaced with the current detected by the current sensor. A charge control unit that performs charge control using output current information,
A storage battery control device equipped with. The reliability determination unit acquires the terminal voltage and the internal resistance of the storage battery when the storage battery is charged by the external charging device, and obtains the current estimated value and the output of the storage battery obtained from the terminal voltage and the internal resistance. The storage battery control device according to claim 1, wherein the reliability of the output current information is determined by comparison with the current information. The reliability determination unit acquires the calorific value and the internal resistance of the storage battery when the storage battery is charged by the external charging device, and obtains the current estimated value and the output of the storage battery obtained from the calorific value and the internal resistance. The storage battery control device according to claim 1 or 2, wherein the reliability of the output current information is determined by comparison with the current information. The reliability determination unit acquires the open circuit voltage of the storage battery before and after the predetermined energization time when the storage battery is charged by the external charging device, and obtains it from the SOC change amount of the storage battery corresponding to the change of the open circuit voltage. The storage battery control device according to any one of claims 1 to 3, wherein the reliability of the output current information is determined by comparing the current estimated value of the storage battery with the output current information. A storage unit for storing the difference between the detected current of the current sensor and the estimated current value as a learning value when it is determined that no abnormality has occurred in the current sensor is provided.
The reliability determination unit corrects the current estimated value by the learning value, and uses the corrected current estimated value to determine the reliability of the output current information. Any one of claims 2 to 4. The storage battery control device described in. A storage battery control device that determines that charging is completed based on the fact that the current flowing through the storage battery drops to a predetermined value when the storage battery is charged by the external charging device.
The charge control unit changes the embodiment of the charge control so that when the charge control is performed based on the output current information, the charge end is accelerated as compared with the case where the charge control is performed based on the current sensor. The storage battery control device according to any one of claims 1 to 5. The reliability determination unit calculates the degree of reliability when it is determined that the output current information is reliable.
The storage battery according to any one of claims 1 to 6, wherein the charge control unit changes an embodiment of charge control carried out based on the output current information according to the degree of reliability of the output current information. Control device. The reliability determination unit has a plurality of determination processes as reliability determination processes for determining the reliability of the output current information, and each of these determination processes is different when the storage battery is charged by the external charging device. A parameter is acquired and the parameter is used to judge the reliability of the output current information.
The charge control unit changes the embodiment of the charge control performed based on the output current information according to which of the plurality of determination processes determines that the output current information is reliable. Item 6. The storage battery control device according to any one of Items 1 to 7.

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