JP2021027750A - Charging rate estimation device - Google Patents

Abstract

To estimate a charging rate of a battery with improved accuracy.SOLUTION: A charging rate estimation device 1 has: a determination unit 121 that determines whether an amount of use of a vehicle Ve per unit time is equal to or higher than a threshold A, and an estimation unit 122. When the determination unit 121 determines that the amount of use of the vehicle Ve per unit time is lower than a threshold Cth, the estimation unit 122 estimates a charging rate of a battery B using a voltage of the battery B by a first estimation method, or when the determination unit 121 determines that the amount of use of the vehicle Ve per unit time is equal to or higher than the threshold A, the estimation unit 122 estimates a charging rate of the battery B using a voltage of the battery B by a second estimation method at a higher frequency than by the first estimation method.SELECTED DRAWING: Figure 1

Description

The present invention relates to a charge rate estimation device that estimates the charge rate of a battery.

As a charge rate estimation device, the charge rate of the battery is estimated sequentially using the integrated value of the current flowing through the battery, and after the required time has elapsed since the ignition of the vehicle on which the battery is mounted is turned off at the start of use of the battery. By estimating the charge rate based on the open circuit voltage of the battery, there is a method of correcting the charge rate including the measurement error of the current sensor. For example, see Patent Document 1. The required time is the time from when the ignition is turned off and no current flows through the battery until the polarization of the battery disappears.

By the way, depending on the usage pattern of the vehicle, the vehicle may be used intermittently so that the ignition off state is short-time. In this case, the charge rate estimation device often estimates the charge rate using the integrated value of the current including the measurement error of the current sensor, rather than estimating the charge rate using the open circuit voltage. There is a risk that the estimation accuracy of

International Publication No. 2013/0544414

An object of one aspect of the present invention is to provide a charge rate estimation device capable of improving the estimation accuracy of the battery charge rate.

The charge rate estimation device according to the present invention is a charge rate estimation device that estimates the charge rate of a battery mounted on a vehicle, and includes a determination unit and an estimation unit.

The determination unit determines whether or not the usage amount of the vehicle per unit time is equal to or greater than the threshold value.
When the determination unit determines that the usage amount of the vehicle per unit time is less than the threshold value, the estimation unit estimates the battery charge rate using the battery voltage by the first estimation method, and the determination unit determines the vehicle unit. When it is determined that the amount used per hour is equal to or higher than the threshold value, the charge rate of the battery is estimated using the voltage of the battery by the second estimation method with a higher frequency than the first estimation method.

Further, the charge rate estimation device according to the present invention is a charge rate estimation device that estimates the charge rate of a battery mounted on a vehicle, and includes a determination unit and an estimation unit.

The determination unit determines whether or not the vehicle is used as a ride-sharing vehicle or a taxi.

When the determination unit determines that the vehicle is not used as a ride-sharing vehicle or taxi, the estimation unit estimates the battery charge rate using the battery voltage by the first estimation method, and the determination unit determines the battery charge rate. When it is determined that the vehicle is being used as a ride-sharing vehicle or taxi, the battery charge rate is estimated using the battery voltage by the second estimation method at a higher frequency than the first estimation method.

In general, the battery charge rate corresponding to the battery voltage can be uniquely obtained. Therefore, estimating the battery charge rate using the battery voltage means charging the battery using the integrated value of the current flowing through the battery. Compared to estimating the rate, the accuracy of estimating the charge rate can be improved because the measurement error of the current meter is not included.

In addition, the open circuit voltage of a battery in a state where no current is flowing after charging or discharging fluctuates so as to approach the true open circuit voltage due to elimination of polarization, so that after a certain period of time has passed after charging or discharging is completed. Estimating the battery charge rate using the battery open circuit voltage is true compared to estimating the battery charge rate using the battery open circuit voltage immediately after charging or discharging is complete. Since the charge rate can be estimated using a voltage close to the open circuit voltage, the charge rate estimation accuracy can be improved.

Also, if the vehicle usage per unit time is above the threshold, or if the vehicle Ve is used as a ride-sharing vehicle or taxi, the vehicle is likely to be used frequently and is charged. Alternatively, charging or discharging is likely to be started again within a certain period of time after the end of discharging.

Therefore, when the usage amount of the vehicle per unit time is equal to or more than the threshold value, or when the vehicle Ve is used as a vehicle or taxi for ride sharing, the usage amount of the vehicle per unit time is less than the threshold value. Compared with the case, it becomes difficult to estimate the charge rate of the battery using the voltage of the battery after a certain period of time has elapsed from the end of charging or discharging, and the estimation accuracy of the charge rate may be lowered.

Therefore, in the charge rate estimation device which is one embodiment of the present invention, when the usage amount per unit time of the vehicle is equal to or more than the threshold value, or when the vehicle Ve is used as a vehicle or a taxi for ride sharing. Uses the battery voltage to determine the battery charge rate compared to when the vehicle usage per unit time is below the threshold or when the vehicle Ve is not used as a ride-sharing vehicle or taxi. The frequency of estimation is high. As a result, when the usage amount of the vehicle per unit time is equal to or higher than the threshold value, or when the vehicle Ve is used as a vehicle for ride sharing or a taxi, the charge rate of the battery is estimated using the voltage of the battery. Since it is possible to reduce the difficulty in performing this, it is possible to suppress a decrease in the estimation accuracy of the charge rate.

In addition, as a first estimation method, the estimation unit estimates the charge rate of the battery using the voltage of the battery when the time when no current is flowing through the battery is longer than the first time, and the second estimation method. As a result, when the time when no current is flowing through the battery is the second time or more, which is shorter than the first time, the charge rate of the battery may be estimated using the voltage of the battery.

As a result, when it is determined that the usage amount of the vehicle per unit time is equal to or higher than the threshold value, the battery charge rate is estimated by using the battery voltage by the second estimation method at a higher frequency than the first estimation method. Can be done.

In addition, as a second estimation method, the estimation unit estimates the charge rate of the battery using the open circuit voltage estimated by the closed circuit voltage of the battery when a current flows through the battery and the vehicle is stopped. It may be configured to do so.

As a result, when it is determined that the usage amount per unit time of the vehicle is equal to or higher than the threshold value, even if a current is flowing through the battery, the closed circuit voltage is used when the vehicle is relatively stable while the vehicle is stopped. Since the circuit voltage can be estimated, it is possible to suppress a decrease in the estimation accuracy of the charge rate by estimating the charge rate of the battery using the estimated open circuit voltage.

In addition, as a second estimation method, the estimation unit uses a case where a current flows through the battery and the vehicle is stopped for a predetermined time or longer, and the fluctuation amount of the current flowing through the battery is equal to or less than a predetermined amount. If the battery temperature is equal to or higher than a predetermined temperature, the battery charge rate may be estimated using the open circuit voltage estimated by the closed circuit voltage of the battery.

As a result, when it is determined that the usage amount per unit time of the vehicle is equal to or higher than the threshold value, the charge rate of the battery can be estimated using a more stable closed circuit voltage, so that the estimation accuracy of the charge rate is lowered. That can be further suppressed.

According to the present invention, the accuracy of estimating the charge rate of the battery can be improved.

It is a figure which shows an example of the battery pack which comprises the charge rate estimation device of embodiment. It is a figure which shows an example of the information stored in the storage part. It is a flowchart which shows the estimation method. It is a flowchart which shows the estimation method in Example 1. FIG. It is a flowchart which shows the estimation method in Example 2. It is a flowchart which shows the estimation method in Example 3. FIG.

Hereinafter, embodiments will be described in detail based on the drawings.
FIG. 1 is a diagram showing an example of a battery pack including the charge rate estimation device of the embodiment.

The battery pack BP shown in FIG. 1 is mounted on a vehicle Ve such as a plug-in hybrid vehicle or an electric vehicle, and includes a battery B and a current meter 2 in addition to the charge rate estimation device 1 (battery ECU (Electronic Control Unit)). , A thermometer 3, switches SW1 and SW2, and a monitoring ECU 4. The vehicle Ve is not limited to a plug-in hybrid vehicle or an electric vehicle, and may be an industrial vehicle such as an electric forklift.

In addition to the battery pack BP, the vehicle Ve controls the operation of the motor M for traveling of the vehicle Ve, the inverter circuit Inv for driving the motor M, and the inverter circuit Inv, and the charger Ch provided outside the vehicle Ve. It is provided with a vehicle ECU 5 that communicates with.

The inverter circuit Inv includes a switch, and when the switch is repeatedly turned on and off, the DC power supplied from the battery B is converted into AC power and supplied to the motor M. Further, the inverter circuit Inv converts the AC power (regenerated power) supplied from the motor M into DC power and supplies it to the battery B by repeatedly turning the switch on and off.

The vehicle ECU 5 changes the duty ratio of the control signal that controls the on / off of the switch of the inverter circuit Inv, so that the electric power supplied from the battery B to the inverter circuit Inv or the electric power supplied from the inverter circuit Inv to the battery B. To control. The function of the vehicle ECU 5 may be included in the function of the charge rate estimation device 1 to integrate the charge rate estimation device 1 and the vehicle ECU 5, and the charge rate estimation device 1 after the integration may be provided in the vehicle Ve.

The battery B is composed of one or more secondary batteries such as a lithium ion battery or a nickel metal hydride battery.

The ammeter 2 is composed of a shunt resistor or the like, detects a current flowing through the battery B, and sends the detected current to the monitoring ECU 4.

The thermometer 3 is composed of a thermistor or the like, detects the temperature of the battery B, and sends the detected temperature to the monitoring ECU 4.

The monitoring ECU 4 is configured to include a processor, a storage unit, and the like, and detects the voltage of the battery B. Further, the monitoring ECU 4 transmits the detected voltage, the current detected by the ammeter 2, and the temperature detected by the thermometer 3 to the full charge capacity estimation device 1 by using CAN (Controller Area Network) communication or the like. ..

The switches SW1 and SW2 are each composed of a semiconductor relay (for example, MOSFET (Metal Oxide Semiconductor Field Effect Transistor)) or an electromagnetic relay. One end of the switch SW1 is connected to the negative terminal of the battery B via the ammeter 2, and the other end of the switch SW1 is connected to the negative input terminal of the inverter circuit Inv. One end of the switch SW2 is connected to the negative terminal of the battery B via the switch SW1 and the ammeter 2, and the other end of the switch SW2 is connected to the negative output terminal of the charging device Ch. One end of the switch SW1 is connected to the positive terminal of the battery B, the other end of the switch SW1 is connected to the positive input terminal of the inverter circuit Inv, and one end of the switch SW2 is connected to the positive terminal of the battery B via the switch SW1. The other end of the switch SW2 may be connected to the positive output terminal of the charging device Ch.

When the switch SW1 becomes conductive and the switch SW2 is cut off, the battery B can supply electric power to the inverter circuit Inv, and the inverter circuit Inv can supply electric power to the battery B1. .. Further, when the switches SW1 and SW2 are electrically connected, the charging device Ch can supply electric power to the battery B. At this time, it is assumed that power is not supplied from the charging device Ch to the inverter circuit Inv. When power is supplied to the battery B from the inverter circuit Inv or the charging device Ch, the battery B is charged and the voltage of the battery B rises, and when the power is supplied from the battery B to the inverter circuit Inv, the battery B is discharged. The voltage of the battery B drops.

The charge rate estimation device 1 includes a storage unit 11 and a processor 12.
The storage unit 11 is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), or the like. Further, the storage unit 11 stores SOC (State Of Charge) -OCV (Open Circuit Voltage) characteristic information D indicating a correspondence relationship between the charge rate of the battery B and the open circuit voltage of the battery B.

FIG. 2 is a diagram showing an example of SOC-OCV characteristic information D. The horizontal axis of the two-dimensional coordinates shown in FIG. 2 indicates the charge rate [%] of the battery B, and the vertical axis indicates the open circuit voltage [V] of the battery B. Further, the solid line shown in FIG. 2 indicates SOC-OCV characteristic information D indicating the correspondence relationship between the charge rate of the battery B and the open circuit voltage, and is assumed to be obtained by experiments, simulations, and the like. The open circuit voltage is the voltage of the battery B detected by the monitoring ECU 4 when the current detected by the ammeter 2 is zero.

In the SOC-OCV characteristic information D shown in FIG. 2, the higher the open circuit voltage of the battery B, the higher the charge rate of the battery B. In other words, when the open circuit voltage of the battery B becomes equal to or higher than the threshold value Ath, the charge rate of the battery B becomes equal to or higher than the threshold value Bth, and when the open circuit voltage of the battery B becomes lower than the threshold value Ath, the charge rate of the battery B becomes lower than the threshold value Bth. It gets lower.

By referring to the SOC-OCV characteristic information D, the charge rate of the battery B corresponding to the open circuit voltage of the battery B can be uniquely obtained.

Further, the processor 12 shown in FIG. 1 controls the operations of the switches SW1 and SW2, and communicates with the monitoring ECU 4 and the vehicle ECU 5 by CAN (Controller Area Network) communication or the like. In the present embodiment, an example in which the processor 12 controls the operation of the switches SW1 and SW2 is given, but the present invention is not limited to this. For example, the vehicle ECU 5 may control the operation of the switches SW1 and SW2.

That is, when the processor 12 receives from the vehicle ECU 5 that the ignition has been switched from the ignition off to the ignition on by the operation of the ignition switch by the user, and then receives from the vehicle ECU 5 that the switch has been switched from the ready-off to the ready-on, the processor 12 shuts off the switch SW1. The charge rate of the battery B is estimated using the voltage, current, temperature, etc. transmitted from the monitoring ECU 4 while switching to the conductive state and the switch SW2 is left in the cutoff state, and the output power command according to the estimated charge rate. The value Wout or the input power command value Win is transmitted to the vehicle ECU 5.

Further, when the processor 12 receives from the vehicle ECU 5 that the ignition is switched from the ignition on to the ignition off by the operation of the ignition switch by the user, the processor 12 stores the last estimated charging rate during the ignition on in the storage unit 11, and then the ready-on. Upon receiving from the vehicle ECU 5 that the switch is switched from to ready-off, the switch SW1 is switched from the conductive state to the cutoff state, and the switch SW2 is left in the cutoff state.

Further, the processor 12 transmits the limited output power command value Wout to the vehicle ECU 5 when the charging rate becomes equal to or less than the first lower limit threshold value, and when the charging rate becomes equal to or higher than the first upper limit threshold value, the limited input power. The command value Win is transmitted to the vehicle ECU 5. The vehicle ECU 5 controls the operation of the inverter circuit Inv so that the power corresponding to the output power command value Wout is supplied from the battery B to the inverter circuit Inv, and the power corresponding to the input power command value Win is supplied from the inverter circuit Inv. The operation of the inverter circuit Inv is controlled so as to be supplied to the battery B. When the output power command value Wout or the input power command value Win is limited, the vehicle ECU 5 reduces the duty ratio of the control signal for controlling the on / off of the switch of the inverter circuit Inv, thereby reducing the duty ratio of the control signal from the battery B to the inverter circuit Inv. The power supplied to the battery B or the power supplied from the inverter circuit Inv to the battery B is limited.

Further, when the charge rate of the battery B becomes equal to or less than the second lower limit threshold value smaller than the first lower limit threshold value, or the charge rate of the battery B becomes larger than the first upper limit threshold value to the second upper limit threshold value or more. Then, by shutting off the switches SW1 and SW2, power is supplied from the battery B to the inverter circuit Inv, power is supplied from the inverter circuit Inv to the battery B, and power is supplied from the charging device Ch to the battery B. Prohibit being supplied. The second lower threshold value is the charge rate of the battery B immediately before the battery B is in the overcharged state, and the second upper limit threshold value is the charge rate of the battery B immediately before the battery B is in the overcharged state. .. As a result, it is possible to prevent the battery B from being in an overcharged state or an overdischarged state.

Further, when the processor 12 conducts the switch SW1 and shuts off the switch SW2, if the voltage transmitted from the monitoring ECU 4 becomes equal to or higher than the overvoltage threshold value, or the current transmitted from the monitoring ECU 4 becomes the overcurrent threshold value. When the above is reached, or when the temperature transmitted from the monitoring ECU 4 exceeds the overtemperature threshold value, it is determined that an abnormality has occurred in the battery B, and that fact is transmitted to the vehicle ECU 5. When the vehicle ECU 5 receives that the battery B has an abnormality, the vehicle ECU 5 stops the inverter circuit Inv and prohibits charging and discharging of the battery B.

Further, the processor 12 includes a determination unit 121 and an estimation unit 122. The determination unit 121 and the estimation unit 122 are realized by the processor 12 executing the program stored in the storage unit 11. The determination unit 121 and the estimation unit 122 execute a method of estimating the charge rate of the battery B.

FIG. 3 is a flowchart showing an estimation method.
First, the determination unit 121 determines whether or not the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth at an arbitrary timing (step S101). The amount of vehicle Ve used per unit time is, for example, the activation period or the number of activations per unit time of vehicle Ve (several hours, days, weeks, months, etc.). Further, the threshold value Cth is, for example, the minimum value of the usage amount of the vehicle Ve per unit time when the vehicle Ve is used as a vehicle for ride sharing or a taxi.

Next, when the determination unit 121 determines that the usage amount of the vehicle Ve per unit time is less than the threshold value Cth (step S101: No), the estimation unit 122 determines the voltage of the battery B by the first estimation method. The charge rate of the battery B is estimated using this (step S102).

On the other hand, when the determination unit 121 determines that the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth (step S101: Yes), the estimation unit 122 has a second frequency higher than that of the first estimation method. The charge rate of the battery B is estimated using the voltage of the battery B by the estimation method of (step S103). For example, the estimation unit 122 refers to the SOC-OCV characteristic information D stored in the storage unit 11, and corresponds to the open circuit voltage detected by the monitoring ECU 4 when the current detected by the ammeter 2 is zero. The charging rate to be performed is estimated as the charging rate of the battery B. Alternatively, the estimation unit 122 calculates the integrated value of the current detected by the current meter 2 and the internal resistance of the battery B from the closed circuit voltage detected by the monitoring ECU 4 when the current detected by the current meter 2 is not zero. The result of addition or subtraction is used as the estimated open circuit voltage of the battery B, the SOC-OCV characteristic information D stored in the storage unit 11 is referred to, and the charging rate corresponding to the estimated open circuit voltage is the charging rate of the battery B. Estimate as. Alternatively, the estimation unit 122 uses two voltages corresponding to each open circuit voltage detected by the monitoring ECU 4 at two different timings after the battery B is discharged or charged and before the polarization of the battery B is eliminated. , Estimate the voltage of the battery B after the polarization of the battery B is eliminated. For example, the estimation unit 122 sets the result of adding one voltage to the multiplication value of the difference between the two voltages and the coefficient as the voltage of the battery B after the polarization of the battery B is eliminated. Then, with reference to the SOC-OCV characteristic information D stored in the storage unit 11, the charge rate corresponding to the voltage of the battery B after the estimated polarization is eliminated is estimated as the charge rate of the battery B.

When the determination unit 121 determines that the vehicle Ve is not used as a vehicle or taxi for ride sharing, the estimation unit 122 uses the voltage of the battery B by the first estimation method to charge the battery B. When the determination unit 121 determines that the vehicle Ve is being used as a vehicle or taxi for ride sharing, the voltage of the battery B is determined by the second estimation method more frequently than the first estimation method. It may be configured to be used to estimate the charge rate of the battery B.

Further, the determination unit 121 may determine that the vehicle Ve is used as a vehicle for ride sharing or a taxi according to the following determination conditions (a) to (f).
(A) When the charging frequency of the battery B is the threshold value Jth or more and the increase amount of the charging rate of the battery B per charge is the threshold value Dth or more, the determination unit 121 indicates that the vehicle Ve is a vehicle for ride sharing or Judge that it is used as a taxi.
(B) The determination unit 121 determines that the vehicle Ve is being used as a vehicle for ride sharing or a taxi when the waiting time after the start of the vehicle Ve is equal to or greater than the threshold value Eth.
(C) The determination unit 121 determines that the vehicle Ve is used for a ride-sharing vehicle or a taxi when the daily mileage of the vehicle Ve is equal to or greater than the threshold value Fth.
(D) The determination unit 121 determines that the vehicle Ve is used for a ride-sharing vehicle or a taxi when the number of working days per week of the vehicle Ve is equal to or greater than the threshold value Gth.
(E) The determination unit 121 determines that the vehicle Ve is used for a ride-sharing vehicle or a taxi when the temperature at the highest frequency of the temperature frequency distribution of the vehicle Ve is equal to or higher than the threshold value Hth.
(F) The determination unit 121 determines that the vehicle Ve is a vehicle for ride sharing when the standby location after the start of the vehicle Ve detected by using the GPS (Global Positioning System) mounted on the vehicle Ve is the same every time. Or it is judged that it is used for a taxi.

In general, the charge rate of the battery B corresponding to the voltage of the battery B can be uniquely obtained. Therefore, estimating the charge rate of the battery B using the voltage of the battery B is an integrated value of the current flowing through the battery B. Compared with estimating the charge rate of the battery B using the battery B, the estimation accuracy of the charge rate can be improved because the measurement error of the current meter 2 is not included.

Further, since the open circuit voltage of the battery B in a state where no current is flowing after charging or discharging fluctuates so as to approach the true opening circuit voltage due to the elimination of polarization, a certain period of time has elapsed since the charging or discharging was completed. Later, estimating the charge rate of battery B using the open circuit voltage of battery B means estimating the charge rate of battery B using the open circuit voltage of battery B immediately after charging or discharging is completed. In comparison, the charge rate can be estimated by using a voltage close to the true open circuit voltage, so that the charge rate estimation accuracy can be improved.

In addition, if the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold value Cth, or if the vehicle Ve is used as a vehicle for ride sharing or a taxi, the vehicle Ve may be frequently used. It is expensive, and charging or discharging is likely to be started again within a certain period of time after charging or discharging is completed.

Therefore, when the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold Cth, or when the vehicle Ve is used as a vehicle or taxi for ride sharing, the usage amount of the vehicle Ve per unit time is the threshold value. Compared to the case where the voltage is less than Cth or the vehicle Ve is not used as a vehicle or taxi for ride sharing, the voltage of the battery B is used after a certain period of time has passed since the charging or discharging is completed. It becomes difficult to estimate the charge rate of the battery, and the estimation accuracy of the charge rate may be lowered.

Therefore, in the charge rate estimation device 1 of the embodiment, when the usage amount of the vehicle Ve per unit time is equal to or more than the threshold Cth, or when the vehicle Ve is used as a vehicle for ride sharing or a taxi, the vehicle Ve Battery B charge rate using battery B voltage compared to when the usage per unit time of is less than the threshold Cth, or when the vehicle Ve is not used as a ride-sharing vehicle or taxi. The frequency of estimation is high. As a result, when the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold Cth, or when the vehicle Ve is used as a vehicle or taxi for ride sharing, that is, the vehicle Ve is frequently used. As a result, when the elapsed time after charging or discharging the battery B is relatively short, it is possible to reduce the difficulty in estimating the charge rate of the battery B using the voltage of the battery B. , It is possible to suppress a decrease in the estimation accuracy of the charge rate.

<Example 1>
FIG. 4 is a flowchart showing the estimation method in the first embodiment.

First, when the determination unit 121 receives from the vehicle ECU 5 that the ignition has been switched from the ignition off to the ignition on (step S201: Yes), the determination unit 121 determines whether or not the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth. (Step S202).

Next, the estimation unit 122 determines that the usage amount of the vehicle Ve per unit time is less than the threshold value Cth by the determination unit 121 (step S202: No), and no current is flowing through the battery B. When the time (the time from the switching of the switch SW1 from the conductive state to the cutoff state after the previous running of the vehicle Ve to the present) is equal to or longer than the first time (step S203: Yes), the voltage of the battery B (open). The charge rate of the battery B is estimated using the circuit voltage) (step S205). In the first time, the polarization is eliminated after the switch SW1 is switched from the conductive state to the cutoff state and no current flows through the battery B, and the open circuit voltage of the battery B is the same as or substantially the same as the true open circuit voltage. It is the time until it becomes. Further, the estimation unit 122 refers to the SOC-OCV characteristic information D stored in the storage unit 11 and estimates the charge rate corresponding to the open circuit voltage detected by the monitoring unit ECU 4 as the charge rate of the battery B. ..

Further, the estimation unit 122 determines that the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth by the determination unit 121 (step S202: Yes), and the time when no current is flowing through the battery B. When is the second time or more (step S204: Yes), the charge rate of the battery B is estimated using the voltage of the battery B (open circuit voltage) (step S205).

When the time when no current is flowing through the battery B is longer than the first time, the first estimation method is to estimate the charge rate of the battery B using the voltage of the battery B. Further, when the time when no current is flowing through the battery B is longer than the second time, the second estimation method is to estimate the charge rate of the battery B using the voltage of the battery B. That is, when it is determined that the usage amount of the vehicle Ve per unit time is less than the threshold value Cth, the estimation unit 122 estimates the charge rate of the battery B by using the voltage of the battery B by the first estimation method. When it is determined that the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth, the charge rate of the battery B is estimated by using the voltage of the battery B by the second estimation method.

Further, the second time is shorter than the first time. Therefore, when the estimation unit 122 determines that the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth, the estimation unit 122 uses the voltage of the battery B by the second estimation method at a higher frequency than the first estimation method. Estimate the charge rate of B.

Further, the estimation unit 122 indicates that the time when no current is flowing through the battery B is less than the first time (step S203: No), or the time when no current is flowing through the battery B is less than the second time. In a certain case (step S204: No), the charge rate stored in the storage unit 11 (the charge rate last estimated during the previous ignition on) is read out (step S206).

Next, when the estimation unit 122 receives from the vehicle ECU 5 that the ready-off has been switched to the ready-on (step S207: Yes), the estimation unit 122 switches the switch SW1 from the cutoff state to the conductive state, and indicates that the ignition is switched to the ignition off. The charge rate of the battery B is repeatedly estimated using the integrated value of the current detected by the ammeter 2 until it is received from the ECU 5 (step S209, step S210: No). For example, the estimation unit 122 calculates the charge rate at the time of this estimation = the charge rate at the time of the previous estimation + (the integrated value of the current detected by the ammeter 2 / the full charge capacity of the battery B) × 100 to obtain the battery. Estimate the charge rate of B. The charge rate at the time of the previous estimation is the charge rate acquired in step S205, step S206, or step S209.

Next, when the estimation unit 122 receives from the vehicle ECU 5 that the ignition is switched from the ignition on to the ignition off (step S212: Yes), the estimation unit 122 stores the last estimated charging rate during the ignition on in the storage unit 11 (step S211). ).

Then, when the estimation unit 122 receives from the vehicle ECU 5 that it has switched from ready-on to ready-off (step S212: Yes), the estimation unit 122 switches the switch SW1 from the conduction state to the cutoff state and keeps the switch SW2 in the cutoff state (step). S213).

As described above, in the charge rate estimation device 1 of the first embodiment, since the second time is set to a time shorter than the first time, it is determined that the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold value Cth. In this case, the charge rate of the battery B can be estimated by using the voltage of the battery B by the second estimation method at a higher frequency than the first estimation method.

<Example 2>
FIG. 5 is a flowchart showing the estimation method in the second embodiment.

First, when the determination unit 121 receives from the vehicle ECU 5 that the ignition has been switched from the ignition off to the ignition on (step S301: Yes), the determination unit 121 determines whether or not the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth. (Step S302).

Next, the estimation unit 122 tells from the vehicle ECU 5 that the ready-off is switched to the ready-on after the determination unit 121 determines that the usage amount of the vehicle Ve per unit time is less than the threshold value Cth (step S302: No). Upon reception (step S303: Yes), the switch SW1 is switched from the cutoff state to the conductive state, the switch SW2 is left in the cutoff state (step S304), and the charge rate stored in the storage unit 11 is read out (step S305).

Next, the estimation unit 122 repeatedly estimates the charge rate of the battery B using the integrated value of the current detected by the ammeter 2 until it receives the fact that the ignition is switched from the ignition on to the ignition off (step S306, step). S307: No). For example, the estimation unit 122 calculates the charge rate at the time of this estimation = the charge rate at the time of the previous estimation + (the integrated value of the current detected by the ammeter 2 / the full charge capacity of the battery B) × 100 to obtain the battery. Estimate the charge rate of B. The charge rate at the time of the previous estimation is the charge rate acquired in step S305 or step S306.

On the other hand, the estimation unit 122 receives from the vehicle ECU 5 that the ready-off has been switched to the ready-on after the determination unit 121 determines that the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold value Cth (step S302: Yes). Then (step S308: Yes), the switch SW1 is switched from the cutoff state to the conduction state, and the switch SW2 is left in the cutoff state (step S309).

Next, when the estimation unit 122 determines that the vehicle Ve is stopped (step S310: Yes), the estimation unit 122 estimates the open circuit voltage of the battery B using the voltage (closed circuit voltage) detected by the monitoring ECU 4. , The estimated open circuit voltage is used to estimate the charge rate of the battery B (step S311). For example, the estimation unit 122 stops the vehicle Ve when the traveling speed of the vehicle Ve transmitted from the vehicle ECU 5 is zero, or when the vehicle ECU 5 receives that the vehicle Ve is stopped. Judge that there is. Further, the estimation unit 122 obtains the estimated open circuit voltage by calculating the estimated open circuit voltage = the closed circuit voltage detected by the monitoring ECU 4- (current detected by the ammeter 2 × internal resistance of the battery B). .. Further, the estimation unit 122 refers to the SOC-OCV characteristic information D stored in the storage unit 11 and estimates the charge rate corresponding to the estimated open circuit voltage as the charge rate of the battery B.

Next, the estimation unit 122 repeatedly estimates the charge rate of the battery B using the integrated value of the current detected by the ammeter 2 until it receives the fact that the ignition is switched from the ignition on to the ignition off (step S312, step). S313: No). For example, the estimation unit 122 calculates the charge rate at the time of this estimation = the charge rate at the time of the previous estimation + (the integrated value of the current detected by the ammeter 2 / the full charge capacity of the battery B) × 100 to obtain the battery. Estimate the charge rate of B. The charge rate at the time of the previous estimation is the charge rate acquired in step S311 or step S312.

On the other hand, when the estimation unit 122 determines that the vehicle Ve is not stopped (the vehicle Ve is running) (step S310: No), the estimation unit 122 does not estimate the charge rate using the voltage of the battery B and starts from the ignition on. The charge rate of the battery B is repeatedly estimated using the integrated value of the current detected by the ammeter 2 until the notification that the ignition is turned off is received (step S312, step S313: No). For example, when the traveling speed of the vehicle Ve transmitted from the vehicle ECU 5 is greater than zero, or when the estimation unit 122 receives from the vehicle ECU 5 that the vehicle Ve is traveling, the vehicle Ve is stopped. It is judged that there is no vehicle (Ve is running).

Further, a series of processes in steps S303 to S307 is used as the first estimation method. Further, a series of processes in steps S308 to S313 is used as the second estimation method. That is, when the switch SW1 is switched from the cutoff state to the conductive state, a current flows through the battery B, and the vehicle Ve is stopped, the battery B uses the open circuit voltage estimated from the closed circuit voltage of the battery B. The second estimation method is to estimate the charge rate of the battery. When the estimation unit 122 receives from the vehicle ECU 5 that the ignition has been switched from the ignition off to the ignition on (step S301: Yes), the estimation unit 122 refers to the SOC-OCV characteristic information D stored in the storage unit 11 and refers to the ammeter. The charge rate corresponding to the open circuit voltage detected by the monitoring ECU 4 when the current detected by 2 is zero is estimated as the charge rate of the battery B, and the estimated charge rate is calculated in step S306 or step described later. It may be used as the charge rate at the time of the previous estimation in S312. In the case of such a configuration, the method of estimating the charge rate using the open circuit voltage after the ignition is turned on is included in the first estimation method.

Next, when the estimation unit 122 receives from the vehicle ECU 5 that the ignition has been switched from the ignition on to the ignition off (step S307: Yes or step S313: Yes), the estimation unit 122 stores the last estimated charge rate during the ignition on in the storage unit 11. Store (step S314).

Then, when the estimation unit 122 receives from the vehicle ECU 5 that it has switched from ready-on to ready-off (step S315: Yes), the estimation unit 122 switches the switch SW1 from the conduction state to the cutoff state and keeps the switch SW2 in the cutoff state (step). S316).

As described above, in the charge rate estimation device 1 of the second embodiment, when it is determined that the usage amount of the vehicle Ve per unit time is less than the threshold Cth, the charge rate of the battery B is estimated by the first estimation method. When it is determined that the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold Cth, the charge rate of the battery B is estimated by using the open circuit voltage of the battery B by the second estimation method. When it is determined that the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold Cth, the battery B is charged by the second estimation method using the open circuit voltage of the battery B more frequently than the first estimation method. The rate can be estimated.

Further, in the charge rate estimation device 1 of the second embodiment, when it is determined that the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold value Cth, even if a current is flowing through the battery B, the comparison is made while the vehicle Ve is stopped. Since the open circuit voltage is estimated using the closed circuit voltage when the target is stable, the estimation accuracy of the charge rate is lowered by estimating the charge rate of the battery B using the estimated open circuit voltage. It can be suppressed.

<Example 3>
FIG. 6 is a flowchart showing the estimation method in the third embodiment. Note that steps S301 to S316 shown in FIG. 6 are the same as steps S301 to S316 shown in FIG. 5, and the description thereof will be omitted.

The difference from the flowchart shown in FIG. 5 in the flowchart shown in FIG. 6 is that after the estimation unit 122 determines that the vehicle Ve is stopped (step S310: Yes), the stop time is less than a predetermined time. Or, when the fluctuation amount of the current flowing through the battery B (the amount of current detected by the current meter 2) is larger than the predetermined amount, or when the temperature of the battery B (the temperature detected by the thermometer 3) is less than the predetermined temperature. In a certain case (step S310': No), the charge rate of the battery B is not estimated using the voltage of the battery B, but the charge rate of the battery B is estimated using the integrated value of the current detected by the current meter 2 (step S312). It is a point.

Further, in the flowchart shown in FIG. 6, another point different from the flowchart shown in FIG. 5 is that after the estimation unit 122 determines that the vehicle Ve is stopped (step S310: Yes), the stop time is a predetermined time. When the above is the case, the fluctuation amount of the current flowing through the battery B is not more than a predetermined amount, and the temperature of the battery B is not more than the predetermined temperature (step S310': Yes), the estimated open circuit voltage. Is used to estimate the charge rate (step S311), and the charge rate of the battery B is estimated using the integrated value of the current detected by the ammeter 2 (step S312).

The series of processes in steps S303 to S307 is used as the first estimation method. Further, a series of processes of steps S308 to S313 including step S310'is used as the second estimation method. That is, when the switch SW1 is switched from the cutoff state to the conductive state, a current flows through the battery B, the stop time of the vehicle Ve is longer than a predetermined time, and the fluctuation amount of the current flowing through the battery B is a predetermined amount. In the following cases and when the temperature of the battery B is equal to or higher than the predetermined temperature, the second method is to estimate the charge rate of the battery B using the open circuit voltage estimated by the closed circuit voltage of the battery B. Use the estimation method.

Further, the predetermined time is the time required from when the switch SW1 is switched from the cutoff state to the conductive state until the fluctuation amount of the closed circuit voltage detected by the monitoring ECU 4 becomes equal to or less than the threshold value Is. Further, the predetermined amount is a fluctuation amount of the current detected by the ammeter 2 when the fluctuation amount of the closed circuit voltage detected by the monitoring ECU 4 becomes equal to or less than the threshold value Is. Further, the predetermined temperature is a temperature detected by the thermometer 3 when the fluctuation amount of the closed circuit voltage detected by the monitoring ECU 4 becomes equal to or less than the threshold value Is. In this way, when the predetermined time, the predetermined amount, and the predetermined temperature are set, a relatively stable closed circuit voltage can be detected. Therefore, the closed circuit voltage can be used to detect the open circuit voltage of the battery B. Can be estimated accurately.

As described above, in the charge rate estimation device 1 of the third embodiment, when it is determined that the usage amount of the vehicle Ve per unit time is less than the threshold Cth, as in the charge rate estimation device 1 of the second embodiment, the first When the charge rate of the battery B is estimated by the estimation method 1 and it is determined that the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold Cth, the estimated open circuit voltage of the battery B is used by the second estimation method. Since the configuration is such that the charge rate of the battery B is estimated, when it is determined that the usage amount of the vehicle Ve per unit time is equal to or greater than the threshold Cth, the second estimation method has a higher frequency than the first estimation method. Therefore, the charge rate of the battery B can be estimated using the open circuit voltage of the battery B.

Further, according to the charge rate estimation device 1 of the third embodiment, when it is determined that the usage amount of the vehicle Ve per unit time is equal to or higher than the threshold value Cth, the charge rate is estimated by using a more stable closed circuit voltage. Therefore, it is possible to further suppress a decrease in the estimation accuracy of the charge rate.

The present invention is not limited to the above embodiments, and various improvements and changes can be made without departing from the gist of the present invention.

1 Charge rate estimation device 2 Ammeter 3 Thermometer 4 Monitoring ECU
5 Vehicle ECU
11 Storage unit 12 Processor 121 Judgment unit 122 Estimating unit

Claims (5)

It is a charge rate estimation device that estimates the charge rate of batteries mounted on vehicles.
A determination unit that determines whether or not the usage amount of the vehicle per unit time is equal to or greater than the threshold value.
When the determination unit determines that the usage amount of the vehicle per unit time is less than the threshold value, the charge rate of the battery is estimated using the voltage of the battery by the first estimation method, and the determination unit determines the charge rate of the battery. When it is determined that the usage amount of the vehicle per unit time is equal to or higher than the threshold value, the charge rate of the battery is estimated by the second estimation method at a higher frequency than the first estimation method using the voltage of the battery. Estimator and
A charge rate estimation device equipped with. It is a charge rate estimation device that estimates the charge rate of batteries mounted on vehicles.
A determination unit that determines whether or not the vehicle is used as a vehicle for ride sharing or a taxi,
When the determination unit determines that the vehicle is not used as a vehicle for ride sharing or a taxi, the charge rate of the battery is estimated using the voltage of the battery by the first estimation method, and the determination unit When it is determined that the vehicle is being used as a vehicle for ride sharing or a taxi, the battery is charged using the voltage of the battery by the second estimation method more frequently than the first estimation method. An estimation unit that estimates the rate and
A charge rate estimation device equipped with. The charge rate estimation device according to claim 1 or 2.
The estimation unit
As the first estimation method, when the time when no current is flowing through the battery is longer than the first time, the charge rate of the battery is estimated using the voltage of the battery.
As the second estimation method, when the time during which no current is flowing through the battery is equal to or longer than the second time shorter than the first time, the charge rate of the battery is estimated using the voltage of the battery. A charging rate estimation device characterized by. The charge rate estimation device according to claim 1 or 2.
As the second estimation method, the estimation unit uses the open circuit voltage estimated by the closed circuit voltage of the battery when the current flows through the battery and the vehicle is stopped. A charge rate estimator characterized by estimating the charge rate. The charge rate estimation device according to claim 4.
In the estimation unit, as the second estimation method, when a current flows through the battery and the vehicle is stopped for a predetermined time or longer, and the amount of fluctuation of the current flowing through the battery is When the amount is equal to or less than a predetermined amount and the temperature of the battery is equal to or higher than a predetermined temperature, the charge rate of the battery is estimated using the open circuit voltage estimated by the closed circuit voltage of the battery. Charge rate estimation device.

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