JP2021048746A - Remaining capacity setting device - Google Patents

Abstract

To provide a remaining capacity setting device that can properly set the remaining capacity of a battery during constant voltage charging.SOLUTION: A remaining capacity setting device that detects a charging current of a battery during constant voltage charging of a battery and sets the remaining capacity of the battery includes a storage state determination unit that determines whether the battery is in a predetermined low storage state at the start of constant voltage charging, a first setting unit that calculates the charging power required until the charging current reaches a predetermined convergence value on the basis of change data of the charging current before the charging current reaches the predetermined convergence value after the start of constant voltage charging, and sets the initial value of the remaining capacity on the basis of the charging power when it is determined that the battery is not in the storage state, and a second setting unit that sets a predetermined value as the initial value of the remaining capacity when the charging current reaches the predetermined convergence value after the start of constant voltage charging when it is determined that the battery is in the low storage state.SELECTED DRAWING: Figure 2

Description

The present invention relates to a remaining capacity setting device for setting the remaining capacity of a battery.

As a device of this type, for example, as seen in Patent Document 1 below, a device that detects the charging current of a battery and sets the remaining capacity of the battery is known. This device detects the charging current of the battery during constant voltage charging of the battery, and based on a plurality of charging current data obtained at a predetermined time, it is based on the integrated charging current value until the charging current value reaches the convergence value. And set the initial value of the remaining capacity. In this method, since the initial value of the remaining capacity is set based on the integrated charging current value, the remaining capacity can be set at an early stage.

Japanese Unexamined Patent Publication No. 2009-126277

However, in the above method, when the battery is in a low storage state, the charging current gradually decreases with charging in the constant voltage charging of the battery, and the time until the convergent value is reached is prolonged. Therefore, the error generated in the initial value of the remaining capacity increases due to the accumulation of the detection error of the charging current value and the like. As a result, the remaining capacity cannot be set appropriately, the capacity range of the usable battery is narrowed, and the deterioration of the battery is promoted.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a residual capacity setting device capable of appropriately setting the remaining capacity of a battery at the time of constant voltage charging.

The first means for solving the above-mentioned problems is a residual capacity setting device that detects the charging current of the battery during constant voltage charging of the battery and sets the remaining capacity of the battery, and starts constant voltage charging. At times, a storage state determination unit that determines whether or not the battery is in a predetermined low storage state, and a charging current after the start of the constant voltage charging when it is determined that the battery is not in the low storage state. Calculates the charging power required for the charging current to reach the converged value based on the change data of the charging current before reaching a predetermined convergence value, and the remaining capacity is calculated based on the charging power. A predetermined value when the charging current reaches a predetermined convergent value after the start of the constant voltage charging when the first setting unit for setting the initial value and the battery are determined to be in the low storage state. Is provided as a second setting unit for setting the initial value of the remaining capacity.

As a method of setting the initial value of the remaining capacity of the battery during constant voltage charging of the battery, the charging current of the battery is detected during constant voltage charging of the battery, and the change of the charging current before the charging current reaches the convergence value. A method of setting the initial value of the remaining capacity is known based on the charging power required for the charging current to reach the convergence value. In this method, since the initial value of the remaining capacity is set before the charging current reaches the convergence value, the remaining capacity can be set early.

However, in the above setting method, an error occurs in the charging power due to the influence of the detection error of the charging current and the efficiency, which causes an error in the initial value of the remaining capacity. In particular, when the battery is in a low storage state, the charging current gradually decreases with charging in the constant voltage charging of the battery, and the time until the convergent value is reached is prolonged. Therefore, as the error in the charging power increases, the error that occurs in the initial value of the remaining capacity increases. As a result, the remaining capacity cannot be set appropriately, the capacity range of the usable battery is narrowed, and the deterioration of the battery is promoted.

In the above configuration, in addition to the first setting method which is the above setting method, a second setting method in which a predetermined value is set as an initial value of the remaining capacity when the charging current reaches the convergence value after the start of constant voltage charging is provided. It can be carried out, and the first setting method and the second setting method are selectively carried out based on the state of charge of the battery at the start of constant voltage charging. Specifically, when the battery is not in the low storage state at the start of constant voltage charging, the first setting method is performed by the first setting unit, and when the battery is in the low storage state, the second setting is performed. The second setting method is carried out by the unit. In the second setting method, since the charging power is not calculated, an error of the charging power does not occur. Further, in the first setting method, although an error in charging power occurs, the implementation is limited to the case where the battery is not in a low charging state, and an increase in the error in charging power is suppressed. That is, regardless of the state of charge of the battery at the start of constant voltage charging, an increase in the error of the charging power can be suppressed, and the remaining capacity of the battery can be set appropriately.

In the second means, the remaining capacity setting device is a device for setting the remaining capacity of the battery mounted on the vehicle, and is an operation determination for determining whether or not an operation for starting the vehicle has been performed. The second setting unit includes a unit, and even when the battery storage state determination unit determines that the battery is not in the low storage state, the operation determination unit determines that the operation is not performed. , The initial value of the remaining capacity is set according to the predetermined value.

In the above configuration, even if the battery is not in a low storage state at the start of constant voltage charging, the second setting method is performed if there is no operation for starting the vehicle. Since there is no operation for starting the vehicle, a relatively long setting period for setting the initial value of the remaining capacity can be secured by the second setting method. Then, by implementing the second setting method, the occurrence of an error in the charging power can be suppressed, and the remaining capacity of the battery can be set appropriately.

In the third means, the remaining capacity setting device is a device for setting the remaining capacity of the battery mounted on the vehicle, the storage state determination unit is the first storage state determination unit, and the low storage capacity is low. The state is the first low storage state, and the first setting unit includes a second storage state determination unit that determines whether or not the battery is in the second low storage state after the start of constant voltage charging. Even when the first storage state determination unit determines that the battery is in the first low storage state, the second storage state determination unit determines that the battery is not in the second low storage state. Sets the initial value of the remaining capacity by the charging power.

In the above configuration, even if the battery is in the first low storage state at the start of constant voltage charging, the first setting method is performed if the battery is no longer in the second low storage state due to constant voltage charging. Since the battery is no longer in the second low storage state, even if the first setting method is performed, an increase in the error of the charging power can be suppressed, and the remaining capacity of the battery can be set appropriately. Then, by implementing the first setting method, the remaining capacity of the battery can be set at an early stage.

In the fourth means, the remaining capacity setting device is a device for setting the remaining capacity of the battery mounted on the vehicle, constant voltage charging is performed when the vehicle is started, and the electricity storage state determination unit is used. , The discharge information of the battery in the parked state of the vehicle is acquired, and based on the discharge information, it is determined whether or not the battery is in the low storage state.

When the vehicle is parked, the remaining capacity of the battery decreases due to the natural discharge of the battery or the like. Therefore, over-discharging of the battery can be suppressed by charging the battery at a constant voltage when the vehicle is started. In the above configuration, when the battery is charged at a constant voltage when the vehicle is started, the discharge information of the battery in the parked state of the vehicle is acquired, and it is determined whether or not the battery is in the low storage state based on the discharge information. Therefore, it is possible to appropriately determine whether or not the battery is in a low storage state, and it is possible to appropriately set the remaining capacity of the battery.

In the fifth means, the storage state determination unit determines that the battery is in the low storage state when the storage amount of the battery at the start of constant voltage charging is smaller than the threshold value, and the battery When the battery is at a low temperature, the storage state determination unit sets the threshold value smaller than when the battery is at a high temperature, and based on the threshold value, the battery makes the battery. Determine whether or not the battery is in a low storage state.

The error in charging power depends on the temperature of the battery, and when the battery is cold, the error is smaller than when the battery is hot. Therefore, in the above configuration, when the battery is at a low temperature, the threshold value is set smaller than when the battery is at a high temperature. That is, when the battery is at a low temperature, the error in the charging power is small, so the threshold value is set small to facilitate the implementation of the first setting method. As a result, the remaining capacity of the battery can be set at an early stage while suppressing an increase in the error of the charging power.

Overall configuration diagram of the power supply system 100. The flowchart of the control process which concerns on 1st Embodiment. The flowchart of the first setting process. The flowchart of the second setting process. A graph showing the relationship between battery temperature and calculation error. A time chart showing the transition of the SOC of the battery in the parked state of the vehicle. A time chart showing control processing when the storage capacity is not low. A time chart showing control processing in a low storage state. A time chart of control processing according to the second embodiment. The flowchart which shows the control process when the accelerator operation is not performed during constant voltage charging. The flowchart of the control process which concerns on 3rd Embodiment. The flowchart which shows the control process when the accelerator operation is performed during constant voltage charging.

(First Embodiment)
Hereinafter, the first embodiment in which the remaining capacity setting device according to the present invention is applied to the in-vehicle power supply system 100 will be described with reference to the drawings.

As shown in FIG. 1, the power supply system 100 according to the present embodiment is a device applied to an in-vehicle battery 10 and controlling SOC (State Of Charge) indicating the state of charge of the battery 10 and charging / discharging. The battery 10 is a rechargeable / dischargeable storage battery, specifically, an assembled battery in which a plurality of lead storage batteries 11 are connected in series. The battery 10 may be another type of storage battery.

The power supply system 100 includes a generator 20, a load 30, and a control device 40 as a remaining capacity setting device. The generator 20 and the load 30 are connected to the battery 10. The generator 20 is a rotary electric machine that is driven by an in-vehicle engine to charge the battery 10, and is, for example, a synchronous machine. The load 30 has a constant voltage required load that requires the voltage of the supplied power to be substantially constant, or at least stable so as to fluctuate within a predetermined range, and a general load other than the constant voltage load.

The power supply system 100 includes a current sensor 51 that detects the charge / discharge current IB of the battery 10 and a voltage sensor 52 that detects the power supply voltage of the battery 10. Each sensor is connected to the control device 40, and the detection value of each sensor is input to the control device 40.

Further, the control device 40 is connected to the IG switch 61, the accelerator sensor 62, and the temperature sensor 63. The IG switch 61 is a vehicle start switch. The control device 40 monitors the on / off state of the IG switch 61. The accelerator sensor 62 is a sensor that detects the accelerator opening degree, that is, the accelerator operation of the vehicle-mounted engine. The temperature sensor 63 is a sensor that detects the temperature YB of the battery 10.

The control device 40 controls the charging / discharging of the battery 10 in order to control the SOC of the battery 10 based on the acquired detection value and the like. For example, when charging the battery 10, the control device 40 determines the amount of power generated by the generator 20 based on the SOC of the battery 10 and the running state of the vehicle, and charges the battery 10.

For example, the load current is supplied from the battery 10 to the control device 40 in the system hibernation state of the power supply system 100 such as when the vehicle is parked. Therefore, the SOC of the battery 10 when the system of the power supply system 100 is started, such as when the vehicle is started, is lower than the SOC of the battery 10 when the system is stopped, such as when the vehicle is parked. Therefore, the control device 40 charges the battery 10 at a constant voltage when the system is started, and suppresses over-discharging of the battery 10.

Then, the control device 40 detects the charge / discharge current IB of the battery 10 and sets the SOC of the battery 10 during the constant voltage charging of the battery 10 at the time of system startup. In this SOC setting, it is determined whether or not the charge / discharge current IB has reached a predetermined convergence value IK (see FIG. 6) after the start of constant voltage charging, and when the convergence value IK is reached, the battery 10 It is determined that the SOC has reached the target value SM (see FIG. 6) as a predetermined value. Here, the convergent value IK is a current value at which constant voltage charging is completed, and the target value SM is a preset storage state corresponding to the convergent value IK.

As a method of setting SOC during constant voltage charging, SOC is set based on the relationship between the elapsed time from the start of constant voltage charging and the charge / discharge current IB, that is, the current approximation formula DB which is the change data of the charge / discharge current IB. There are known ways to do this. In this setting method, a current approximation formula DB is calculated based on a plurality of charge / discharge current IBs detected in the current acquisition period HA (see FIG. 7), which is a predetermined period after the start of constant voltage charging, and this current approximation formula DB is calculated. The initial value of SOC of the battery 10 is set based on the DB. Here, the initial value means the SOC that is set for the first time after the system of the power supply system 100 is started.

Specifically, based on the calculated current approximation formula DB, the power charged in the battery 10 by the time the charge / discharge current IB reaches the convergence value IK, that is, until the charge / discharge current IB reaches the convergence value IK. Calculate the charging power CA required for. Then, the value obtained by subtracting the increase amount ΔSU of SOC due to the charging power CA from the target value SM is set as the initial value of SOC of the battery 10. In this setting method, by using the current approximation formula DB, the initial value of SOC can be set after the start of constant voltage charging and before the charge / discharge current IB reaches the convergence value IK, and the SOC of the battery 10 can be set. Can be set early. In this embodiment, SOC corresponds to "residual capacity".

By the way, in the above setting method, an error P is generated in the charging power CA due to the influence of the detection error of the charge / discharge current IB and the charging efficiency in the calculation of the current approximation formula DB. The error P is the sum of the current error ΔP obtained by subtracting the charge / discharge current IB in the current approximation formula DB from the actually detected charge / discharge current IB at each elapsed time over the constant voltage charging period HC (). (See FIG. 7). In the present embodiment, since the influence of the charging efficiency is not taken into consideration in the calculation of the current approximation formula DB, the charge / discharge current IB in the current approximation formula DB is smaller than the actually detected charge / discharge current IB, and the current error ΔP is It will be a positive value.

Therefore, when the battery 10 is in a predetermined low storage state, for example, the charging start capacity SF, which is the SOC of the battery 10 at the start of constant voltage charging, is smaller than the threshold value Sth, the constant voltage charging of the battery 10 is performed. , The charge / discharge current IB gradually decreases with charging, and the time until the convergence value IK is reached is prolonged. Therefore, the error P of the charging power CA increases due to the accumulation of the current error ΔP, and the error generated in the initial value of the SOC of the battery 10 increases. As a result, the SOC cannot be set properly, the capacity range of the usable battery 10 is narrowed, and the deterioration of the battery 10 is promoted.

Therefore, in addition to the first setting method which is the above setting method, the control device 40 of the present embodiment sets the target value SM as a battery when the charge / discharge current IB reaches the convergence value IK after the start of constant voltage charging. The second setting method of setting the initial value of the SOC of 10 can be implemented, and the first setting method and the second setting method are selectively implemented based on the charge state of the battery 10 at the start of constant voltage charging. To do. Specifically, the control device 40 implements the first setting method when the battery 10 is not in the low storage state at the start of constant voltage charging, and the second setting when the battery 10 is in the low storage state. Implement the control process that implements the method.

Next, the control process according to the present embodiment will be described with reference to FIG. This control process is performed during constant voltage charging when the vehicle is started. This control process is repeatedly executed by the control device 40 at a predetermined cycle.

First, in step S10, it is determined whether or not the charging start capacity SF has already been calculated. In this case, for example, if the charging start capacity SF calculated by the previously executed control process is stored in the storage unit 41, an affirmative determination is made in step S10. In this case, the process proceeds to step S14.

On the other hand, if the charging start capacity SF is not stored in the storage unit 41, a negative determination is made in step S10. In this case, in step S12, the charging start capacity SF is calculated. For example, the storage unit 41 stores the parking start capacity SP, which is the SOC of the battery 10 at the start of parking of the vehicle. Further, the storage unit 41 stores the charge / discharge current IB acquired in the reference cycle in the parked state of the vehicle. Hereinafter, the charge / discharge current IB acquired in the parked state of the vehicle and the parking start capacity SP are referred to as discharge information.

In step S12, these discharge information is acquired from the storage unit 41, and the charge start capacity SF is calculated based on the discharge information. Specifically, the discharge power CB, which is the power discharged from the battery 10 in the parked state of the vehicle, is calculated based on the charge / discharge current IB acquired in the parked state of the vehicle, and the SOC is reduced by this discharge power CB. The amount ΔSD (see FIG. 6) subtracted from the parking start capacity SP is calculated as the charge start capacity SF.

Since the calculation accuracy of the charge start capacity SF is low, this charge start capacity SF cannot be set as the initial value of the SOC of the battery 10.

In step S14, the temperature sensor 63 is used to acquire the temperature YB of the battery 10. In the following step S16, the threshold value Sth is set based on the temperature YB acquired in step S14. In this embodiment, the process of step S14 corresponds to the “temperature acquisition unit”.

In step S16, when the battery 10 is at a low temperature, the threshold value Sth is set smaller than when the battery 10 is at a high temperature. Here, the low temperature is a state in which the temperature YB is lower than the predetermined threshold temperature Yth, and the high temperature is a state in which the temperature YB is higher than the threshold temperature Yth. As shown in FIG. 5, when the battery 10 is at a low temperature, the current error ΔP is smaller than when the battery 10 is at a high temperature, and the error P is unlikely to increase. In this case, the threshold value Sth is set small.

In the following step S18, it is determined whether or not the battery 10 is in a low storage state at the start of constant voltage charging. Specifically, it is determined whether or not the charging start capacity SF calculated in step S12 is smaller than the threshold value Sth set in step S16. In the present embodiment, the charge start capacity SF corresponds to the "battery charge amount", and the process in step S18 corresponds to the "charge state determination unit, the first charge state determination unit".

When the charging start capacity SF is larger than the threshold value Sth, it is determined that the battery 10 is not in a low storage state, and a negative determination is made in step S18. In this case, in step S20, the first setting method is performed and the control process is terminated. In this embodiment, the process of step S20 corresponds to the "first setting unit".

The first setting process for carrying out the first setting method will be described with reference to FIG. In the first setting process, first, in step S30, the charge / discharge current IB is acquired. In the following step S32, it is determined whether or not the current acquisition period HA has elapsed from the start of the constant voltage charging.

If a negative determination is made in step S32, the first setting process ends. On the other hand, if an affirmative determination is made in step S32, the current approximation formula DB is calculated in step S34 based on the plurality of charge / discharge currents IB acquired during the current acquisition period HA. For the calculation of the current approximation formula DB, a well-known approximation method such as the least squares method can be used.

In step S36, the charging power CA is calculated based on the current approximation formula DB calculated in step S34. In the following step S38, the initial value of SOC is set by the charging power CA calculated in step S36, and the first setting process is completed.

On the other hand, when the charging start capacity SF is smaller than the threshold value Sth, it is determined that the battery 10 is in a low storage state, and an affirmative determination is made in step S18. In this case, in step S20, the second setting method is performed and the control process is terminated. In this embodiment, the process of step S22 corresponds to the "second setting unit".

The second setting process for carrying out the second setting method will be described with reference to FIG. In the second setting process, first, in step S40, the charge / discharge current IB is acquired. In the following step S42, it is determined whether or not the charge / discharge current IB acquired in step S40 has reached the convergence value IK. Specifically, it is determined whether or not the acquired charge / discharge current IB is smaller than the convergence value IK.

If a negative determination is made in step S42, the second setting process ends. On the other hand, if an affirmative determination is made in step S42, the initial value of SOC is set by the target value SM in step S44, and the second setting process is terminated.

FIG. 6 is a time chart showing the transition of the SOC of the battery 10 in the parked state of the vehicle. In FIG. 6, (A) shows the transition of the state of the power supply system 100, (B) shows the transition of the charge / discharge current IB, (C) shows the transition of the discharge power CB, and (D) shows the transition of the discharge power CB. , The transition of the SOC of the battery 10 is shown.

When the IG switch 61 is switched to the off state by the driver at the timing t1, the power supply system 100 is switched from the system operating state to the system hibernation state. In the power supply system 100, the load current flows from the battery 10 to the control device 40 even after the system is switched to the hibernation state, and the discharge power CB increases. The SOC of the battery 10 at the timing t1 is the parking start capacity SP.

In the present embodiment, the load current flows during the period from the timing t1 to the timing t2 in the system hibernation state, the discharge power CB increases, and the SOC of the battery 10 decreases. Then, when the load current is stopped at the timing t2, the battery 10 is freely discharged during the period from the timing t2 to the timing t3 in the system hibernation state, and a dark current flows. As a result, the discharge power CB increases and the SOC of the battery 10 decreases. That is, in the system hibernation state, the battery 10 continues to discharge, and the SOC of the battery 10 continues to decrease.

Then, when the IG switch 61 is switched to the on state by the driver at the timing t3, the power supply system 100 is switched from the system hibernation state to the system operating state. As a result, the discharge of the battery 10 is stopped, and the decrease of the SOC is stopped. The SOC of the battery 10 at the timing t3 is the charge start capacity SF.

Further, the constant voltage charging of the battery 10 is started at the timing t3. As a result, the charge / discharge current IB rises sharply and then gradually falls with charging to reach the convergence value IK. Further, the SOC of the battery 10 increases toward the target value SM. Then, at this timing t3, the control process is started.

7 and 8 are time charts specifically showing the control process of the present embodiment. FIG. 7 is a time chart of control processing when the battery 10 is not in a low storage state, and FIG. 8 is a time chart of control processing when the battery 10 is not in a low storage state.

In FIGS. 7 and 8, (A) shows the transition of the charge / discharge current IB, (B) shows the transition of the current error occurrence flag, and (C) shows the transition of the error P. The current error generation flag is turned on when the current error ΔP has occurred, and turned off when the current error ΔP has not occurred. The error P is the sum of the current error ΔP over the constant voltage charging period HC, and in the present embodiment, the constant voltage charging period HC was actually detected after the constant voltage charging was started. The period until the charge / discharge current IB reaches the convergence value IK is shown.

Further, in FIG. 7, (D) shows the transition of the electricity storage state setting flag. The charge state setting flag is turned on when the initial value of the SOC of the battery 10 can be set in each setting method, and is turned off when the above setting is not possible.

In (A) of FIGS. 7 and 8, the charge / discharge current IB actually detected by the current sensor 51 is shown by a solid line, and the charge / discharge current IB in the current approximation formula DB is shown by a broken line. .. Further, in FIGS. 8B and 8C, the transition of each value when the second setting method is implemented is shown by a solid line, and the transition of each value when the first setting method is implemented. Is indicated by a broken line.

As shown in FIG. 7, when the battery 10 is not in the low storage state, the charge start capacity SF is larger than the threshold value Sth, and the charge / discharge current IB at the start of constant voltage charging is smaller than the threshold current Is. In this case, the first setting method is implemented.

In the first setting method, the acquisition of the charge / discharge current IB is started at the timing t3. The charge / discharge current IB is acquired for each control process, that is, at a predetermined cycle. Then, when the acquisition of the charge / discharge current IB required for the calculation of the current approximation formula DB is completed at the timing t11, the acquisition of the charge / discharge current IB is completed. At the same time, the storage state setting flag is turned on, and the current approximation formula DB is calculated based on the plurality of charge / discharge current IBs acquired during the current acquisition period HA from the timing t3 to the timing t11.

As shown by the broken line in FIG. 7A, the charge / discharge current IB in the current approximation formula DB decreases with the elapsed time and reaches the convergence value IK at the timing t12. Then, the SOC of the battery 10 becomes the target value SM. In the first setting method, the charging power CA for charging the battery 10 from the timing t11 to the timing t12 is calculated. Then, by subtracting the increase amount ΔSU of the SOC due to the charging power CA from the target value SM, the SOC of the battery 10 at the timing t11 is calculated, and this SOC is set as the initial value of the SOC of the battery 10. Therefore, in the first setting method, the initial value of the SOC of the battery 10 can be set before the timing 13 when the actually detected charge / discharge current IB reaches the convergence value IK, and the SOC can be set at an early stage.

As shown in FIG. 7A, a current error ΔP occurs between the actually detected charge / discharge current IB and the charge / discharge current IB in the current approximation formula DB. That is, the current error generation flag is turned on during the current integration period HE from the timing t11 to the timing t12. Therefore, the error P increases in this current integration period HE, and the error P becomes the maximum value at the timing t12. The maximum error PX, which is the maximum value of the error P, is expressed as in (Equation 1) by using the current error ΔP and the current integration period HE.

PX = ΔP × HE ... (Equation 1)
When the maximum error PX becomes larger than the error threshold value Pth, the SOC of the battery 10 cannot be set properly.

In the present embodiment, the implementation of the first setting method is limited to the case where the battery 10 is not in a low storage state. That is, the constant voltage charging period HC is limited, and in detail, the current integration period HE is limited. Therefore, the maximum error PX calculated using the current integration period HE is also limited, it is possible to prevent the maximum error PX from becoming larger than the error threshold value Pth, and the SOC of the battery 10 can be set appropriately.

Further, as shown in FIG. 8, when the battery 10 is in a low storage state, the charge start capacity SF is smaller than the threshold value Sth, and the charge / discharge current IB at the start of constant voltage charging is larger than the threshold current Is. In this case, the second setting method is implemented.

In the second setting method, the acquisition of the charge / discharge current IB is started at the timing t3. Then, when the actually detected charge / discharge current IB reaches the convergence value IK at the timing t13, the acquisition of the charge / discharge current IB is completed, the storage state setting flag is turned on, and the target value SM is the battery 10. It is set as the initial value of SOC.

Here, as shown by the broken lines in FIGS. 8A to 8C, it is assumed that the first setting method is performed when the battery 10 is in a low storage state. In this case, similarly to FIG. 7, a current error ΔP occurs in the current integration period HE from the timing t11 to the timing t12. Then, at the timing t12, the error P becomes the maximum error PX.

In this case, since the battery 10 is in a low storage state, the constant voltage charging period HC is not limited, and the current integration period HE is not limited. Therefore, the maximum error PX calculated using the current integration period HE is not limited, and the maximum error PX may be larger than the error threshold Pth. As a result, the SOC of the battery 10 cannot be set properly.

In the present embodiment, when the charge start capacity SF is smaller than the threshold value Sth, the second setting method is implemented. As shown by the solid line in FIG. 8 (A), in the second setting method, the current approximation formula DB is not calculated, so that the current error ΔP does not occur. Therefore, the occurrence of the error P can be suppressed, and the maximum error PX can be suppressed to be larger than the error threshold value Pth, so that the SOC of the battery 10 can be set appropriately.

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

-As a method of setting the initial value of SOC of the battery 10 during constant voltage charging of the battery 10, the charge / discharge current IB of the battery 10 is detected during the constant voltage charging of the battery 10, and the charge / discharge current IB becomes the convergence value IK. A first setting method is known in which an initial value of SOC is set based on a change in the charge / discharge current IB and a charging power CA required for the charge / discharge current IB to reach the convergence value IK before reaching. In this method, since the initial value of the SOC is set before the charge / discharge current IB reaches the convergence value IK, the SOC can be set at an early stage.

However, in the first setting method, an error P is generated in the charging power CA due to the influence of the detection error of the charge / discharge current IB and the efficiency, and an error is generated in the initial value of the SOC. In particular, when the battery 10 is in a low storage state, in the constant voltage charging of the battery 10, the charge / discharge current IB gradually decreases with charging, and the time until the convergence value IK is reached is prolonged. Therefore, as the error P of the charging power CA increases, the error that occurs in the initial value of the SOC increases. As a result, the SOC cannot be set properly, the capacity range of the usable battery 10 is narrowed, and the deterioration of the battery 10 is promoted.

In the present embodiment, in addition to the first setting method, a second setting method in which the target value SM is set as the initial value of the SOC when the charge / discharge current IB reaches the convergence value IK can be implemented, and a constant voltage can be implemented. The first setting method and the second setting method are selectively implemented based on the charge state of the battery 10 at the start of charging. Specifically, when the battery 10 is not in the low storage state at the start of constant voltage charging, the first setting method is performed, and when the battery 10 is in the low storage state at the start of constant voltage charging, the first setting method is performed. The second setting method is carried out. In the second setting method, since the charging power CA is not calculated, the error P of the charging power CA does not occur. Further, in the first setting method, although an error P occurs, the implementation is limited to the case where the battery 10 is not in the low charge state, and the increase of the error P is suppressed. That is, regardless of the state of charge of the battery 10 at the start of constant voltage charging, an increase in the error P of the charging power CA can be suppressed, and the SOC of the battery 10 can be set appropriately.

-In the parked state of the vehicle, the SOC of the battery 10 decreases due to the load current of the battery 10 and the like. Therefore, over-discharging of the battery 10 can be suppressed by charging the battery 10 at a constant voltage when the vehicle is started. In the present embodiment, when the battery 10 is charged at a constant voltage when the vehicle is started, the discharge information of the battery 10 in the parked state of the vehicle is acquired, and based on the discharge information, whether or not the battery 10 is in a low storage state is determined. judge. Therefore, it is possible to appropriately determine whether or not the battery 10 is in a low storage state, and it is possible to appropriately set the SOC of the battery 10.

The error P of the charging power CA depends on the temperature YB of the battery 10, and when the battery 10 is at a low temperature, the error P becomes smaller than when the battery 10 is at a high temperature. Therefore, in the present embodiment, when the battery 10 is at a low temperature, the threshold value Sth is set smaller than when the battery 10 is at a high temperature. That is, when the battery 10 is at a low temperature, the error P of the charging power CA is smaller than when the battery 10 is at a high temperature, so the threshold value Sth is set small. This makes it easier to implement the first setting method, and the SOC of the battery 10 can be set at an early stage.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to FIGS. 9 and 10, focusing on the differences from the first embodiment. The present embodiment is different from the first embodiment in that it is determined whether or not the accelerator operation is performed by the driver during constant voltage charging. In this embodiment, the accelerator operation corresponds to the "operation for starting".

The control process according to the present embodiment will be described with reference to FIG. In FIG. 9, the same processes as those shown in FIG. 2 above are given the same step numbers for convenience, and the description thereof will be omitted.

In the control process of the present embodiment, if a negative determination is made in step S18, it is determined in step S50 whether or not the accelerator operation has been performed by using the accelerator sensor 62. If an affirmative determination is made in step S50, the process proceeds to step S20. On the other hand, if a negative determination is made in step S50, the process proceeds to step S22. That is, even if it is determined in step S18 that the battery 10 is not in a low storage state, if it is determined in step S50 that the accelerator operation has not been performed, the second setting method is carried out. In this embodiment, the process of step S50 corresponds to the "operation determination unit".

FIG. 10 is a time chart of control processing when the accelerator operation is not performed during constant voltage charging. In FIG. 10, (D) shows the transition of the accelerator operation. Note that FIGS. 10A to 10C are the same as FIGS. 7 and 8A to 8C, and description thereof will be omitted.

As shown in FIG. 10, when the battery 10 is not in the low storage state, the first setting method is first implemented, and the acquisition of the charge / discharge current IB is started at the timing t3. Then, if the accelerator operation is not performed by the driver by the timing t11, the setting method is switched from the first setting method to the second setting method.

Then, as shown by the solid line in FIG. 10A, when the actually detected charge / discharge current IB reaches the convergence value IK at the timing t13, the acquisition of the charge / discharge current IB is completed and the target value SM is completed. Is set as the initial value of the SOC of the battery 10.

-According to the present embodiment described above, even if the battery 10 is not in a low storage state at the start of constant voltage charging, the second setting method is carried out if there is no accelerator operation by the driver. When there is no accelerator operation by the driver, the period until the vehicle starts is long, and a relatively long setting period for setting the initial value of SOC can be secured by the second setting method. Then, by implementing the second setting method, the occurrence of the error P of the charging power CA can be suppressed, and the SOC of the battery 10 can be set appropriately.

(Third Embodiment)
Hereinafter, the third embodiment will be described with reference to FIGS. 11 and 12, focusing on the differences from the first embodiment. This embodiment is different from the first embodiment in that the charging medium capacity SC, which is the SOC of the battery 10 during constant voltage charging, is calculated after the start of constant voltage charging.

The charging medium capacity SC is calculated using the charging start capacity SF. For example, as shown in FIG. 12, when calculating the charging capacity SC at the timing t22 after the start of constant voltage charging, the charging power CA, which is the power charged to the battery 10 during the period from the timing t3 to the timing t22. Is calculated. Then, the charging middle capacity SC is calculated by adding the increase amount ΔSU of the SOC due to the charging power CA to the charging start capacity SF. Hereinafter, the charging power CA and the increase amount ΔSU calculated for setting the initial value of the SOC of the battery 10 in the first setting method are referred to as the first charging power CA1 and the first increase amount ΔSU1. Further, the charging power CA and the increase amount ΔSU calculated for calculating the charging middle capacity SC are referred to as a second charging power CA2 and a second increase amount ΔSU2.

Next, the control process according to the present embodiment will be described with reference to FIG. In FIG. 11, the same processes as those shown in FIG. 2 above are given the same step numbers for convenience, and the description thereof will be omitted.

In the control process of the present embodiment, if an affirmative determination is made in step S18, it is determined in step S60 whether or not the accelerator operation has been performed by using the accelerator sensor 62. In this embodiment, the process of step S60 corresponds to the "operation determination unit". If a negative determination is made in step S60, the process proceeds to step S22.

On the other hand, if an affirmative determination is made in step S60, the charging capacity SC is calculated in step S62. Since the charging medium capacity SC is calculated using the charging start capacity SF, the calculation accuracy of the charging medium capacity SC is low. Therefore, this charging capacity SC cannot be set as the initial value of the SOC of the battery 10.

In the following step S64, it is determined whether or not the battery 10 is in a low storage state after the start of constant voltage charging. Specifically, it is determined whether or not the charging capacity SC estimated in step S62 is larger than the threshold value Sth set in step S16. In the present embodiment, the low storage state corresponds to the "first low storage state, the second low storage state", and the process in step S64 corresponds to the "second storage state determination unit".

When the charging capacity SC is smaller than the threshold value Sth, it is determined that the battery 10 is in a low storage state, and an affirmative determination is made in step S64. In this case, the process proceeds to step S22. On the other hand, when the charging capacity SC is larger than the threshold value Sth, it is determined that the battery 10 is not in the low storage state, and a negative determination is made in step S64. In this case, the process proceeds to step S20. That is, even if it is determined in step S18 that the battery 10 is in a low storage state, the first setting method is carried out when it is determined in step S64 that the battery 10 is not in a low storage state.

FIG. 12 is a time chart of control processing when the accelerator operation is performed during constant voltage charging. Note that (A) to (E) in FIG. 12 are the same as (A) to (E) in FIG. 10, and the description thereof will be omitted.

As shown in FIG. 12, when the battery 10 is in a low storage state, the second setting method is first implemented, and the acquisition of the charge / discharge current IB is started at the timing t3. Then, at the timing t21, the driver operates the accelerator, and at the subsequent timing t32, when the charging capacity SC becomes smaller than the threshold value Sth, the setting method is switched from the second setting method to the first setting method.

Then, as shown by the broken line in FIG. 12A, the current approximation formula DB is calculated based on the plurality of charge / discharge currents IB acquired during the current acquisition period HA from the timing t22 to the timing t23. Then, using the current approximation formula DB, the first charging power CA1 to be charged in the battery 10 during the current integration period HE from the timing t23 to the timing t24 is calculated. Then, by subtracting the first increase amount ΔSU1 of the SOC due to the first charging power CA1 from the target value SM, the SOC of the battery 10 at the timing t23 is calculated, and this SOC is set as the initial value of the SOC of the battery 10. To. That is, the initial value of the SOC of the battery 10 is set based on the charge / discharge current IB acquired from the timing t22 to the timing t23, not the charge / discharge current IB acquired from the timing t3 to the timing t22.

In the present embodiment, when the battery 10 is no longer in a low storage state, the setting method is switched from the second setting method to the first setting method. That is, the current integration period HE in the first setting method is limited. Therefore, the maximum error PX calculated using the current integration period HE is also limited, it is possible to prevent the maximum error PX from becoming larger than the error threshold value Pth, and the SOC of the battery 10 can be set appropriately.

-According to the present embodiment described above, even if the battery 10 is in a low storage state at the start of constant voltage charging, if the battery 10 is no longer in a low storage state due to constant voltage charging, the first setting method is performed. carry out. Since the battery 10 is no longer in a low storage state, even if the first setting method is performed, an increase in the error P of the first charging power CA1 can be suppressed, and the SOC of the battery 10 can be set appropriately. Then, by implementing the first setting method, the SOC of the battery 10 can be set at an early stage.

In particular, in the present embodiment, if there is an accelerator operation by the driver and the battery 10 is no longer in a low storage state due to constant voltage charging, the first setting method is implemented. Therefore, by implementing the first setting method, the period from the accelerator operation by the driver to the setting of the SOC of the battery 10 can be shortened.

(Other embodiments)
The present invention is not limited to the contents described in the above-described embodiment, and may be implemented as follows.

The set remaining capacity of the battery 10 is not limited to the SOC, and may be the remaining power of the battery 10.

-The determination as to whether or not the battery 10 is in a low storage state is not limited to the determination using the charge start capacity SF. For example, it may be determined whether or not the battery 10 is in a low storage state depending on the parking period of the vehicle, and if the vehicle is parked for a long period of time, it is determined that the battery 10 is in a low storage state. You may. In this case, the parking period of the vehicle corresponds to "discharge information".

For example, the control device 40 has a function of stopping the load current supply from the battery 10 to the control device 40 when the SOC of the battery 10 becomes smaller than the threshold value Sth in the parked state of the vehicle. is there. In this case, if the load current supply from the battery 10 to the control device 40 is stopped when the vehicle is started, it may be determined that the battery 10 is in a low storage state. In this case, stopping the load current supply corresponds to "discharge information".

Further, the control device 40 has a function of stopping the load current supply from the battery 10 to the control device 40 when the charge / discharge current IB of the battery 10 becomes smaller than a constant value in the parked state of the vehicle. There may be. In this case, if the load current supply from the battery 10 to the control device 40 is stopped when the vehicle is started, it may be determined that the battery 10 is in a low storage state.

When the parking start capacity SP is not stored in the storage unit 41, the discharge power CB, which is the power discharged from the battery 10 in the parked state of the vehicle, is calculated, and the battery 10 is calculated based on the discharge power CB. May be determined whether or not is in a low storage state. For example, when the load current supply from the battery 10 to the control device 40 is stopped, the parking start capacity SP stored in the storage unit 41 is reset.

-The method of calculating the charge start capacity SF is not limited to the above embodiment. For example, when the charge / discharge current IB of the battery 10 is smaller than a certain value in the parked state of the vehicle, the detection accuracy of the charge / discharge current IB is lowered, so that charging starts based on the elapsed time from the start of parking of the vehicle. The capacitance SF may be calculated.

The change in the charging current used in the first setting method is not limited to the current approximation formula DB, and may be any correlation data showing the relationship between the elapsed time from the start of constant voltage charging and the charge / discharge current IB. In addition to the current approximation formula DB, the correlation data includes a current approximation map in which data showing the relationship between the elapsed time from the start of constant voltage charging and the charge / discharge current IB is stored.

-The operation for starting the vehicle is not limited to the accelerator operation by the driver, but may be the brake release operation or the shift lever operation by the driver. Then, when at least one of these operations is performed, it may be determined that the operation for starting the vehicle has been performed.

-Although the example in which constant voltage charging is carried out at the start of the vehicle is shown, it is not limited to this. For example, when the vehicle is temporarily stopped while the vehicle is running, constant voltage charging may be performed at the time of starting after the suspension.

-As the setting parameter of the threshold value Sth, the temperature YB of the battery 10 has been illustrated, but the present invention is not limited to this. For example, the degree of deterioration of the battery 10 may be used as a setting parameter.

-In the second embodiment, an example is shown in which the first low storage state and the second low storage state are set to the same low storage state, but different low storage states may be set. In this case, for example, the threshold value Sth used in step S18 and the threshold value Sth used in step S64 may be set separately.

10 ... Battery, 40 ... Control device, IB ... Charge / discharge current.

Claims (5)

A remaining capacity setting device (40) that detects the charging current (IB) of the battery during constant voltage charging of the battery (10) and sets the remaining capacity of the battery.
A storage state determination unit that determines whether or not the battery is in a predetermined low storage state at the start of constant voltage charging,
When it is determined that the battery is not in the low storage state, the charging current is increased based on the change data of the charging current after the start of the constant voltage charging and before the charging current reaches a predetermined convergence value. A first setting unit that calculates the charging power required to reach the convergence value and sets the initial value of the remaining capacity based on the charging power.
When the battery is determined to be in the low storage state and the charging current reaches a predetermined convergence value after the start of the constant voltage charging, a predetermined value is set as the initial value of the remaining capacity. A remaining capacity setting device including two setting units. The remaining capacity setting device is a device for setting the remaining capacity of the battery mounted on the vehicle.
It is provided with an operation determination unit for determining whether or not the operation for starting the vehicle has been performed.
The second setting unit has the predetermined value when the operation determination unit determines that the operation has not been performed even when the battery storage state determination unit determines that the battery is not in the low storage state. The remaining capacity setting device according to claim 1, wherein the initial value of the remaining capacity is set according to the above. The remaining capacity setting device is a device for setting the remaining capacity of the battery mounted on the vehicle.
The power storage state determination unit is a first power storage state determination unit.
The low storage state is the first low storage state.
A second storage state determination unit for determining whether or not the battery is in the second low storage state after the start of constant voltage charging is provided.
In the first setting unit, even when the first storage state determination unit determines that the battery is in the first low storage state, the second storage state determination unit keeps the battery in the second low storage state. The remaining capacity setting device according to claim 1 or 2, wherein if it is determined that the value is not the same, the initial value of the remaining capacity is set by the charging power. The remaining capacity setting device is a device for setting the remaining capacity of the battery mounted on the vehicle.
Constant voltage charging is carried out at the start of the vehicle.
Claims 1 to 3 that the storage state determination unit acquires the discharge information of the battery in the parked state of the vehicle, and determines whether or not the battery is in the low storage state based on the discharge information. The remaining capacity setting device according to any one of the above items. The storage state determination unit determines that the battery is in the low storage state when the storage amount of the battery at the start of constant voltage charging is smaller than the threshold value (Sth).
A temperature acquisition unit for acquiring the temperature of the battery is provided.
When the battery is at a low temperature, the storage state determination unit sets the threshold value smaller than when the battery is at a high temperature, and determines whether or not the battery is in the low storage state based on the threshold value. The remaining capacity setting device according to any one of claims 1 to 4.

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