JP6855835B2 - Battery full charge capacity estimation device - Google Patents

Description

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

As an existing battery full charge capacity estimation device, the charge rate difference value which is the result of subtracting the charge rate of the battery at the start of charging from the charge rate of the battery at the end of charging, and the integrated value of the current flowing through the battery being charged. The integrated current value is calculated, and the result of dividing the integrated current value by the difference in charge rate is estimated as the full charge capacity of the battery.

As a related technique, for example, there is Patent Document 1.

Japanese Unexamined Patent Publication No. 2009-591701

However, in the existing battery full charge capacity estimation device, when estimating the full charge capacity of a battery having a large polarization and requiring a long time to eliminate the polarization (for example, a lithium ion battery using a SiO negative electrode), the battery is charged. The SOC-OCV curve that shows the correspondence between the battery charge rate and the battery open circuit voltage, which is obtained later, and the SOC-OCV curve that is obtained after the battery is discharged are not the same, and the charge corresponding to the open circuit voltage is not the same. Since the rate cannot be uniquely determined, the charge rate difference value cannot be calculated accurately, and the estimation accuracy of the full charge capacity may decrease.

An object of the present invention is to provide a battery full charge capacity estimation device capable of improving the estimation accuracy of the full charge capacity of a battery having a large polarization and taking a long time to eliminate the polarization. ..

The battery full charge capacity estimation device, which is one embodiment of the present invention, includes a storage unit, an estimation unit, and a determination unit.

The storage unit includes a charging SOC-OCV curve showing the correspondence between the battery charge rate obtained after charging the battery and the battery open circuit voltage, and the battery charge rate and open circuit voltage obtained after the battery is discharged. The SOC-OCV curve for discharge showing the correspondence between the above is stored.

The estimation unit calculates the charge rate difference value, which is the result of subtracting the charge rate of the battery at the start of charging from the charge rate of the battery at the end of charging, and the current integrated value, which is the integrated value of the current flowing through the battery being charged. The calculated result of dividing the integrated current value by the difference in charge rate is estimated as the full charge capacity of the battery.

The determination unit determines whether or not a point corresponding to the current battery charge rate and the current battery open circuit voltage exists on the discharge SOC-OCV curve or the charge SOC-OCV curve.
At the start of estimating the full charge capacity, the estimation unit determines that a point corresponding to the current battery charge rate and the current battery open circuit voltage exists on the discharge SOC-OCV curve. Then, the SOC-OCV curve for discharging is referred to, and the charging rate corresponding to the open circuit voltage of the battery before charging is set as the charging rate of the battery at the start of charging, and the SOC-OCV curve for charging is referred to. The charge rate corresponding to the open circuit voltage of the battery after charging is defined as the charge rate of the battery at the end of charging.

At the start of estimating the full charge capacity, the estimation unit determines that a point corresponding to the current battery charge rate and the current battery open circuit voltage exists on the charging SOC-OCV curve. Then, the charging SOC-OCV curve is referred to, and the charging rate corresponding to the open circuit voltage of the battery before charging is set as the charging rate of the battery at the start of charging, and the charging SOC-OCV curve is referred to. The charging rate corresponding to the open circuit voltage of the battery after charging is defined as the charging rate of the battery at the end of charging.

According to the present invention, it is possible to improve the estimation accuracy of the full charge capacity of a battery having a large polarization and requiring a long time to eliminate the polarization.

It is a figure which shows an example of the battery full charge capacity estimation apparatus of embodiment. It is a figure which shows an example of the SOC-OCV curve for charging, the SOC-OCV curve for discharging, and the internal division ratio information. It is a flowchart which shows an example of the operation of the determination part. It is a flowchart which shows an example of the operation of the estimation part. It is a flowchart which shows another example of the operation of the estimation part. It is a figure which shows the fluctuation example of the voltage of a battery in an EV mode period, an HV mode period, and a charger charging period. It is a figure which shows an example of the internal fraction ratio information for charge and the internal fraction ratio information for discharge.

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

The battery full charge capacity estimation device shown in FIG. 1 estimates the charge rate of the battery B, and estimates the full charge capacity of the switch SW, the current detection unit 1, the voltage detection unit 2, the storage unit 3, and the storage unit 3. It includes a part 4.

The battery B may be composed of, for example, one secondary battery (for example, a lithium ion battery, a nickel hydrogen battery, or an electric double layer capacitor), or may be composed of two or more secondary batteries. .. Further, when the switch SW is conducting, when power is supplied from the charger Ch to the battery B, or the vehicle Ve (for example, a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle, etc.) on which the battery B is mounted, etc. ) Load Lo (for example, a motor) supplies the regenerative power to the battery B, the battery B is charged. Further, when power is supplied from the battery B to the load Lo when the switch SW is conducting, the battery B is discharged. Further, the battery B has a large polarization and takes a long time to eliminate the polarization, and as shown in FIGS. 2A and 2B, the charge rate SOC of the battery B obtained after charging is obtained. Shows the correspondence between the charging SOC-OCV curve showing the correspondence between (State Of Charge) and the open circuit voltage OCV (Open Circuit Voltage), and the correspondence between the charge rate SOC of the battery B obtained after discharging and the open circuit voltage OCV. It is assumed that the SOC-OCV curves for discharge are not the same as each other. The charge rate SOC indicates the ratio [%] of the current capacity of the battery B to the full charge capacity of the battery B. Further, the charging SOC-OCV curve and the discharging SOC-OCV curve are acquired by, for example, an experiment or a simulation, and are acquired after a lapse of a predetermined time after the charging or discharging of the battery B is completed. To do.

The current detection unit 1 shown in FIG. 1 is composed of, for example, a Hall element or a shunt resistor, and detects the current I flowing through the battery B.

The voltage detection unit 2 is composed of, for example, an IC (Integrated Circuit), and detects the voltage V of the battery B.

The storage unit 3 is composed of, for example, a ROM (Read Only Memory) or a RAM (Random Access Memory), and has a charging SOC-OCV curve and a discharging SOC-OCV curve shown in FIGS. 2 (a) and 2 (b). , And the internal division ratio information showing the correspondence between the capacity difference and the internal division ratio shown in FIG. 2C is stored. The capacity difference is the difference between the capacity of the battery B after charging and the capacity of the battery B before charging, or the difference between the capacity of the battery B before discharging and the capacity of the battery B after discharging. The internal division ratio is the line segment in the open circuit voltage axis direction or the line segment in the charge rate axis direction between the charging SOC-OCV curve and the discharging SOC-OCV curve, and is used for charging SOC-OCV curve or discharging. It is a ratio at the time of internal division at a predetermined internal division point corresponding to the current charge rate of the battery B and the open circuit voltage with reference to the SOC-OCV curve.

When the capacity difference between the capacity of the battery B after charging and the capacity of the battery B before charging is equal to or greater than the threshold value Cth shown in FIG. 2 (c), the battery after charging corresponds to the open circuit voltage of the battery B after charging. The charge rate of B is consistent with the charge rate SOC shown in the charging SOC-OCV curve shown in FIGS. 2 (a) and 2 (b). That is, when the capacity difference between the capacity of the battery B after charging and the capacity of the battery B before charging is equal to or greater than the threshold value Cth shown in FIG. Corresponding points exist on the charging SOC-OCV curve shown in FIGS. 2 (a) and 2 (b). In other words, the threshold Cth is necessary to shift from the state where the point corresponding to the charge rate of the battery B and the open circuit voltage exists on the discharge SOC-OCV curve to the state where it exists on the charge SOC-OCV curve. Shows a large capacity difference. In this way, when a point corresponding to the charge rate of the battery B after charging and the open circuit voltage exists on the SOC-OCV curve for charging, the charge rate is uniquely derived from the open circuit voltage of the battery B after charging. Can be estimated.

When the capacity difference between the capacity of the battery B before discharge and the capacity of the battery B after discharge is equal to or greater than the threshold Cth shown in FIG. 2 (c), the capacity after discharge corresponds to the open circuit voltage OCV of the battery B after discharge. The charge rate of the battery B is consistent with the charge rate SOC shown in the discharge SOC-OCV curves shown in FIGS. 2 (a) and 2 (b). That is, when the capacity difference between the capacity of the battery B before discharge and the capacity of the battery B after discharge is equal to or greater than the threshold value Cth shown in FIG. Corresponding points exist on the discharge SOC-OCV curves shown in FIGS. 2 (a) and 2 (b). In other words, the threshold Cth is necessary to shift from the state where the point corresponding to the charge rate of the battery B and the open circuit voltage exists on the charging SOC-OCV curve to the state where it exists on the discharging SOC-OCV curve. Shows a large capacity difference. In this way, when a point corresponding to the charge rate of the battery B after discharge and the open circuit voltage exists on the SOC-OCV curve for discharge, the charge rate is uniquely derived from the open circuit voltage of the battery B after discharge. Can be estimated. The threshold value Cth may be a different value between charging and discharging.

When the battery B is charged from the state where the point corresponding to the charge rate of the battery B after discharge and the open circuit voltage exists on the SOC-OCV curve for discharge, and the capacity of the battery B after charging When the capacity difference between the battery B and the capacity of the battery B before charging is less than the threshold Cth, the internal division ratio of the internal division ratio information corresponding to the capacity difference is the SOC-OCV curve for charging and the SOC-OCV curve for discharging. How far is the point where the charge rate of the battery B after charging and the open circuit voltage correspond to the discharge SOC-OCV curve in the line line in the direction of the open circuit voltage axis or the line in the direction of the charge rate axis? Is shown.

When the battery B is discharged from the state where the point corresponding to the charge rate of the battery B after charging and the open circuit voltage exists on the SOC-OCV curve for charging, and the capacity of the battery B before discharging. When the capacity difference between the battery B and the capacity of the battery B after discharging is less than the threshold Cth, the internal division ratio of the internal division ratio information corresponding to the capacity difference is the SOC-OCV curve for charging and the SOC-OCV curve for discharging. How far is the point where the charge rate of the battery B after discharge and the open circuit voltage correspond to the charging SOC-OCV curve in the line line in the direction of the open circuit voltage axis or the line line in the direction of the charge rate axis? Is shown.

Further, the full charge capacity estimation unit 4 shown in FIG. 1 is composed of, for example, a CPU (Central Processing Unit), a multi-core CPU, or a programmable device (FPGA (Field Programmable Gate Array), PLD (Programmable Logic Device), etc.). A determination unit 41, an estimation unit 42, and a control unit 43 are provided. For example, the determination unit 41, the estimation unit 42, and the control unit 43 are realized by executing a program in which a CPU, a multi-core CPU, or a programmable device is stored in a storage unit 3 or the like.

The determination unit 41 determines whether or not a point corresponding to the current charge rate of the battery B and the open circuit voltage of the current battery B exists on the discharge SOC-OCV curve or the charging SOC-OCV curve. judge.

When the switch SW is shut off, the estimation unit 42 acquires the voltage V detected by the voltage detection unit 2 as the current open circuit voltage of the battery B. The estimation unit 42 acquires the voltage V detected by the voltage detection unit 2 as the current open circuit voltage of the battery B when the switch SW is conducting and no current is flowing through the battery B. You may.

Further, the estimation unit 42 indicates that the current charging rate of the battery B and the current open circuit voltage of the battery B correspond to each other on the discharge SOC-OCV curve or the charging SOC-OCV at the start and end of charging. The full charge capacity of the battery B is estimated only when it exists on the curve.

That is, the estimation unit 42 has a point on the discharge SOC-OCV curve where the current charge rate of the battery B and the current open circuit voltage of the battery B correspond to each other at the start of estimating the full charge capacity of the battery B. When the determination unit 41 determines that the voltage is correct, the discharge SOC-OCV curve is referred to, and the charge rate corresponding to the open circuit voltage of the battery B before charging is set as the charge rate of the battery B at the start of charging. When the determination unit 41 determines that a point corresponding to the charge rate of the battery B after charging and the open circuit voltage of the battery B after charging exists on the charging SOC-OCV curve, the charging SOC With reference to the −OCV curve, the charge rate corresponding to the open circuit voltage of the battery B after charging is defined as the charge rate of the battery B at the end of charging.

Further, the estimation unit 42 has a point on the charging SOC-OCV curve where the current charge rate of the battery B and the current open circuit voltage of the battery B correspond to each other at the start of estimating the full charge capacity of the battery B. When the determination unit 41 determines that the battery B is charging, the charging SOC-OCV curve is referred to, and the charging rate corresponding to the open circuit voltage of the battery B before charging is set as the charging rate of the battery B at the start of charging. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery B after charging is defined as the charging rate of the battery B at the end of charging.

Further, the estimation unit 42 has a charge rate difference value which is the result of subtracting the charge rate of the battery B at the start of charging from the charge rate of the battery B at the end of charging, and an integrated value of the current flowing through the battery B being charged. The integrated current value is calculated, and the result of dividing the integrated current value by the difference in charge rate is estimated as the full charge capacity of the battery B.

The control unit 43 controls the charging / discharging of the battery B.
That is, the control unit 43 has a point on the discharge SOC-OCV curve where the current charge rate of the battery B and the current open circuit voltage of the battery B correspond to each other at the start of estimating the full charge capacity of the battery B. If it is determined by the determination unit 41 that the battery B is charged, the battery B is charged after obtaining the charge rate of the battery B at the start of charging.

Further, the control unit 43 has a point on the charging SOC-OCV curve where the current charge rate of the battery B and the current open circuit voltage of the battery B correspond to each other at the start of estimating the full charge capacity of the battery B. If it is determined by the determination unit 41 that the battery B is charged, the battery B is charged after obtaining the charge rate of the battery B at the start of charging.

FIG. 3 is a flowchart showing an example of the operation of the determination unit 41.
First, the determination unit 41 obtains the discharge capacity difference between the capacity of the battery B before discharge and the capacity of the battery B after discharge, and determines whether or not the discharge capacity difference is equal to or greater than the threshold value Cth (S31). For example, the determination unit 41 obtains the integrated value ΔI [Ah] of the current I detected by the current detection unit 1 at each detection timing from the start of discharge to the end of discharge of the battery B, and the calculated integration value ΔI [Ah]. Let the value ΔI be the discharge capacity difference. Alternatively, for example, the determination unit 41 determines ΔSOC [%] = ((capacity of battery B before discharge [Ah] -capacity of battery B after discharge [Ah]) / fully charged capacity of battery B [Ah]) ×. 100 is calculated, and ΔSOC, which is the calculation result, is used as the discharge capacity difference. Alternatively, for example, the determination unit 41 calculates ΔV = (voltage V of the battery B before discharge-voltage V of the battery B after discharge), and ΔV, which is the calculation result, is used as the discharge capacity difference. Further, the discharge capacity difference may be the sum of the discharge capacity differences when the discharge is repeated intermittently.

Next, when the determination unit 41 determines that the discharge capacity difference is equal to or greater than the threshold value Cth (S31: Yes), the point corresponding to the current charge rate of the battery B and the open circuit voltage is on the discharge SOC-OCV curve. It is determined that the battery exists in (S32).

On the other hand, when the determination unit 41 determines that the discharge capacity difference is less than the threshold value Cth (S31: No), the determination unit 41 obtains the charge capacity difference between the capacity of the battery B after charging and the capacity of the battery B before charging, and charges the battery B. It is determined whether or not the capacity difference is equal to or greater than the threshold value Cth (S33). For example, the determination unit 41 obtains the integrated value ΔI [Ah] of the current I detected by the current detection unit 1 at each detection timing from the start of charging to the end of charging of the battery B, and the calculated integrated value ΔI Is the difference in charging capacity. Alternatively, for example, the determination unit 41 determines ΔSOC [%] = ((capacity of battery B after charging [Ah] -capacity of battery B before charging [Ah]) / fully charged capacity of battery B [Ah]) ×. 100 is calculated, and ΔSOC, which is the calculation result, is used as the charge capacity difference. Alternatively, for example, the determination unit 41 calculates ΔV = (voltage V of the battery B after charging-voltage V of the battery B before charging), and ΔV, which is the calculation result, is used as the charge capacity difference. Further, the above charge capacity difference may be the sum of the charge capacity differences when charging is repeated intermittently.

Next, when the determination unit 41 determines that the charge capacity difference is equal to or greater than the threshold value Cth (S33: Yes), the point corresponding to the current charge rate of the battery B and the open circuit voltage is on the charging SOC-OCV curve. It is determined that the battery exists in (S34).

On the other hand, when the determination unit 41 determines that the charge capacity difference is less than the threshold value Cth (S33: No), the point that the current charge rate of the battery B after discharge or charge corresponds to the open circuit voltage is discharged. It is determined that it is not known whether or not the battery exists on the SOC-OCV curve for charging or the SOC-OCV curve for charging (S35).

FIG. 4 is a flowchart showing an example of the operation of the estimation unit 42.
First, the estimation unit 42 determines by the determination unit 41 that a point corresponding to the current charge rate of the battery B and the open circuit voltage exists on the discharge SOC-OCV curve at the start of full charge capacity estimation. Then (when the point corresponding to the charge rate of the battery B and the open circuit voltage exists on the discharge SOC-OCV curve at the start of charging) (S41: Yes), refer to the discharge SOC-OCV curve. Then, the charging rate corresponding to the open circuit voltage of the battery B before charging is defined as the charging rate of the battery B at the start of charging (S42). For example, the estimation unit 42 determines that at the start of full charge capacity estimation, a point corresponding to the current charge rate of the battery B and the current open circuit voltage of the battery B exists on the discharge SOC-OCV curve. When determined by the unit 41, referring to the discharge SOC-OCV curve shown in FIG. 2A, the charge rate SOC11 corresponding to the open circuit voltage OCV11 before charging is set as the charge rate of the battery B at the start of charging. To do.

Next, in FIG. 4, the estimation unit 42 charges the battery B by the control unit 43 (S43).

Next, when the estimation unit 42 determines that the difference in charge capacity obtained in the charging operation of S43 is equal to or greater than the threshold value Cth (at the end of charging, the point where the charge rate of the battery B and the open circuit voltage correspond to each other is charged. (When present on the SOC-OCV curve for charging) (S44: Yes), refer to the SOC-OCV curve for charging, and set the charging rate corresponding to the open circuit voltage of the battery B after charging to the battery at the end of charging. Let the charge rate be B (S45). For example, when the estimation unit 42 determines that the charge capacity difference is equal to or greater than the threshold value Cth after charging the battery B, the estimation unit 42 refers to the charging SOC-OCV curve shown in FIG. 2A and refers to the charged SOC-OCV curve of the charged battery. The charge rate SOC12 corresponding to the open circuit voltage OCV12 of B is defined as the charge rate of the battery B at the end of charging.

Next, in FIG. 4, the estimation unit 42 sets the charge rate difference value, which is the result of subtracting the charge rate of the battery B at the start of charging from the charge rate of the battery B at the end of charging, and the battery B being charged. The integrated current value, which is the integrated value of the flowing current, is calculated, and the result of dividing the integrated current value by the charge rate difference value is estimated as the full charge capacity of the battery B (S46). For example, the estimation unit 42 uses the result of subtracting the charge rate SOC11 of the battery B at the start of charging from the charge rate SOC12 of the battery B at the end of charging shown in FIG. 2A as the charge rate difference value. Further, for example, the estimation unit 42 obtains the integrated value ΔI [Ah] of the current I detected by the current detection unit 1 at each detection timing from the start of charging to the end of charging of the battery B, and obtains the total value ΔI [Ah]. Let the integrated value ΔI be the integrated current value.

On the other hand, in FIG. 4, when the estimation unit 42 determines that the charge capacity difference obtained in the charging operation of S43 is less than the threshold value Cth (S44: No), the estimation unit 42 does not estimate the full charge capacity (S47).

Further, the estimation unit 42 determines by the determination unit 41 that a point corresponding to the current charge rate of the battery B and the open circuit voltage exists on the charging SOC-OCV curve at the start of full charge capacity estimation. Then (when the point corresponding to the charge rate of the battery B and the open circuit voltage exists on the charging SOC-OCV curve at the start of charging) (S41: No, S48: Yes), the charging SOC- With reference to the OCV curve, the charge rate corresponding to the open circuit voltage of the battery B before charging is defined as the charge rate of the battery B at the start of charging (S49). For example, the estimation unit 42 determines that at the start of full charge capacity estimation, a point corresponding to the current charge rate of the battery B and the current open circuit voltage of the battery B exists on the charging SOC-OCV curve. When determined by the unit 41, the charging rate SOC21 corresponding to the open circuit voltage OCV21 of the battery B before charging is determined by referring to the charging SOC-OCV curve shown in FIG. 2B, and the charging rate SOC21 of the battery B at the start of charging is determined. Let it be the charge rate.

Next, in FIG. 4, the estimation unit 42 charges the battery B by the control unit 43 (S50).

Next, the estimation unit 42 refers to the charging SOC-OCV curve, and sets the charging rate corresponding to the open circuit voltage of the battery B after charging as the charging rate of the battery B at the end of charging (S45). For example, after charging the battery B, the estimation unit 42 refers to the charging SOC-OCV curve shown in FIG. 2B, and determines the charging rate SOC22 corresponding to the open circuit voltage OCV22 of the battery B after charging. Let it be the charge rate of battery B at the end of charging. If there is a point on the charging SOC-OCV curve where the charge rate of the battery B and the open circuit voltage correspond to each other at the start of charging, the charge rate of the battery B and the open circuit voltage will be the same even at the end of charging. Corresponding points are on the charging SOC-OCV curve.

Next, in FIG. 4, the estimation unit 42 sets the charge rate difference value, which is the result of subtracting the charge rate of the battery B at the start of charging from the charge rate of the battery B at the end of charging, and the battery B being charged. The integrated current value, which is the integrated value of the flowing current, is calculated, and the result of dividing the integrated current value by the charge rate difference value is estimated as the full charge capacity of the battery B (S46). For example, the estimation unit 42 uses the result of subtracting the charge rate SOC21 of the battery B at the start of charging from the charge rate SOC22 of the battery B at the end of charging shown in FIG. 2B as the charge rate difference value. Further, for example, the estimation unit 42 obtains the integrated value ΔI [Ah] of the current I detected by the current detection unit 1 at each detection timing from the start of charging to the end of charging of the battery B, and obtains the total value ΔI [Ah]. Let the integrated value ΔI be the integrated current value.

Further, in FIG. 4, the estimation unit 42 indicates that the current charge rate of the battery B at the start of full charge capacity estimation and the open circuit voltage correspond to each other on the discharge SOC-OCV curve or the charging SOC-OCV curve. If it is determined by the determination unit 41 that it is not known whether or not the battery B exists (S41: No, S48: No), the full charge capacity of the battery B is not estimated (S47).

As described above, in the battery full charge capacity estimation device of the embodiment, the point that the current charge rate of the battery B and the current open circuit voltage of the battery B correspond to each other at the start and end of charging is the SOC-OCV for discharge. The configuration is such that the full charge capacity of the battery B is estimated only when it exists on the curve or the SOC-OCV curve for charging. As a result, the charge rate of the battery B at the start of charging can be uniquely obtained by using the SOC-OCV curve for discharging or the SOC-OCV curve for charging, and the charge rate of the battery B at the end of charging can be obtained by the SOC for charging. It can be uniquely obtained using the −OCV curve. Therefore, even if the battery B has a large polarization and takes a long time to eliminate the polarization, the charge rate difference value can be calculated accurately, and the full charge capacity of the battery B can be estimated accurately. Can be done.

Further, 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.
FIG. 5 is a flowchart showing another example of the operation of the estimation unit 42. Since S41 to S50 shown in FIG. 5 are the same as S41 to S50 shown in FIG. 4, the description thereof will be omitted.

The estimation unit 42 determines whether or not a point corresponding to the current charge rate of the battery B at the start of full charge capacity estimation and the open circuit voltage exists on the discharge SOC-OCV curve or the charging SOC-OCV curve. When the determination unit 41 determines that the battery B is not known (S41: No, S48: No), the charging SOC-OCV curve indicates that the current charge rate of the battery B and the open circuit voltage correspond to each other by the control unit 43. After charging the battery B until it is present on the top (S51), the charging of the battery B is stopped (S52). For example, the estimation unit 42 charges the charge capacity difference battery B having a threshold value Cth or more in S51. Alternatively, in the above S51, the estimation unit 42 comes to have a point on the charging SOC-OCV curve where the current charge rate of the battery B and the open circuit voltage correspond to each other based on the current internal division ratio. The remaining charge capacity difference required by the above is obtained, and the battery B is charged by the remaining charge capacity difference. It should be noted that the charging amount may be larger than the charging amount required for the point corresponding to the charging rate of the battery B and the open circuit voltage to exist on the charging SOC-OCV curve. Further, for example, the estimation unit 42 suspends the charging of the battery B in S52 by setting the current command value sent from the control unit 43 to the charger Ch to zero.

Next, the estimation unit 42 refers to the charging SOC-OCV curve, and sets the charging rate corresponding to the open circuit voltage of the battery B during charging suspension as the charging rate of the battery B at the start of charging (S53). Note that the estimation unit 42 has a voltage V detected by the voltage detection unit 2 while the battery B is not charging (when no current is flowing from the charger Ch to the battery B) and the switch SW is conducting. The closed circuit voltage) may be acquired as the “open circuit voltage of the battery B during charging suspension”. Further, the subsequent operations of the estimation unit 42 (S50, S45, S46) are the same as the operations of S50, S45, and S46 shown in FIG.

As described above, in the operation example of the estimation unit 42 shown in FIG. 5, the point corresponding to the current charge rate of the battery B and the open circuit voltage at the start of estimation of the full charge capacity is on the discharge SOC-OCV curve or charging. When the determination unit 41 determines that it is not known whether or not the battery exists on the SOC-OCV curve for charging, the point corresponding to the current charging rate of the battery B and the open circuit voltage is on the SOC-OCV curve for charging. In the charging suspension of the battery B after charging the battery B until it becomes present, the charging SOC-OCV curve is referred to, and the charging rate corresponding to the open circuit voltage of the battery B during the charging suspension is started to be charged. It corresponds to the open circuit voltage of the battery B after charging by referring to the SOC-OCV curve for charging after charging the battery B after resuming the charging of the battery B, as well as the charging rate of the battery B at the time. The charging rate is defined as the charging rate of the battery B at the end of charging. As a result, even if it is not known whether or not the corresponding point between the charge rate of the battery B and the open circuit voltage exists on the SOC-OCV curve for discharge or the SOC-OCV curve for charging, charging starts. Since the charge rate of the battery B at the time and the charge rate of the battery B at the end of charging can be calculated accurately, the charge rate difference value can be calculated accurately, and the full charge capacity of the battery B can be estimated accurately. can do.

Further, for example, when the control unit 43 starts charging the battery B by the charger Ch, when the point corresponding to the current charge rate of the battery B and the open circuit voltage does not exist on the discharge SOC-OCV curve. , The current internal division ratio is obtained from the running history of the vehicle Ve on which the battery B is mounted, and the charge rate of the battery B and the open circuit voltage correspond to each other by using the obtained internal division ratio and the internal division ratio information for charging. The charging capacity difference required until the point to be charged exists on the SOC-OCV curve for charging is obtained, the obtained charging capacity difference battery B is charged, and then the charging of the battery B is stopped. You may.

For example, assume that the vehicle Ve is a plug-in hybrid vehicle.
FIG. 6 shows a period in which the vehicle Ve travels by the electric power supplied from the battery B (EV mode period), a period in which the vehicle Ve travels by the electric power supplied from the battery B or the driving force of the gasoline engine (HV mode period). It is a figure which shows the example of the fluctuation of the voltage of the battery B in the period (charger charging period) that the battery B is charged by the charger Ch.

First, the control unit 43 periodically obtains the current internal division ratio during the EV mode period and the HV mode period shown in FIG. 6, and stores the internal division ratio in the storage unit 3 as a “vehicle running history”.
Next, the control unit 43 corresponds to the current charge rate of the battery B and the open circuit voltage when the HV mode period shown in FIG. 6 is switched to the charger charging period, that is, when charging by the charger Ch is started. When the determination unit 41 determines that is not present on the discharge SOC-OCV curve, the latest internal division ratio pa of the internal division ratios stored in the storage unit 3 is referred to as the "current internal division ratio". Ask as.

Next, the control unit 43 obtains the charging capacity difference a corresponding to the current internal division ratio pa with reference to the charging internal division ratio information shown in FIG. 7A.

Next, the control unit 43 sets the value obtained by subtracting the charge capacity difference a from the threshold value Cth1 until a point corresponding to the charge rate of the battery B and the open circuit voltage exists on the charging SOC-OCV curve. The charge capacity difference b required for

Then, after charging the battery B by the charge capacity difference b, the control unit 43 suspends the charging of the battery B in order to obtain the charging rate at the start of charging used for estimating the full charge capacity.
The charge capacity difference b may be a value larger than the value obtained by subtracting the charge capacity difference a from the threshold value Cth1.

For example, it is assumed that the end of the HV mode period ends with discharging and the charging is performed during the charging period of the charger, and the charging is switched from discharging to charging.

FIG. 7A is a diagram showing an example of charging internal division ratio information showing a correspondence relationship between the internal division ratio and the capacity difference between the capacity of the battery B after charging and the capacity of the battery B before charging. 7 (b) is a diagram showing an example of the internal division ratio information for discharge showing the correspondence relationship between the internal division ratio and the capacity difference between the capacity of the battery B before discharge and the capacity of the battery B after discharge. is there. The internal division ratio information for charging and the internal division ratio information for discharging are stored in the storage unit 3. The internal division ratio shown in the charging internal ratio information shown in FIG. 7A and the internal division ratio shown in the discharging internal division information shown in FIG. 7B both have a discharge SOC-OCV curve. It is the standard. Further, the threshold value Ch1 shown in FIG. 7A and the threshold value Ch2 shown in FIG. 7B may be the same value or may be different values.

First, as shown in FIGS. 7 (b) and 7 (c), when the state of the battery B switches from the discharge in the HV mode period to the charge in the charger charging period, the estimation unit 42 sets the threshold value of the capacity difference of the discharge immediately before the switch. If it is less than, the internal division ratio pa is obtained by referring to the traveling history of the vehicle up to that point and the internal division ratio information for discharge. Then, with reference to the charging internal division ratio information shown in FIG. 7A, the charging capacity difference a corresponding to the internal division ratio pa is obtained. After that, since the contents are the same as those described above, they are omitted.

In this way, at the start of charging by the charger Ch, the current internal division ratio pa is obtained from the traveling history of the vehicle Ve, and the charging rate of the battery B is obtained by using the obtained internal division ratio pa and the internal division ratio information for charging. The charging capacity difference b required for the point corresponding to the open circuit voltage to exist on the charging SOC-OCV curve is obtained, and after charging the battery B for the obtained charging capacity difference b, the battery B is charged. Since the charging of the battery B is suspended, the charging rate at the start of charging can be accurately obtained during the charging suspension, and the estimation accuracy of the full charge capacity can be improved.

1 Current detection unit 2 Voltage detection unit 3 Storage unit 4 Full charge capacity estimation unit B Battery SW switch

Claims (4)

A charging SOC-OCV curve showing the correspondence between the battery charge rate obtained after charging the battery and the open circuit voltage of the battery, and the charge rate obtained after the battery is discharged and the open circuit voltage. A storage unit that stores the SOC-OCV curve for discharge showing the correspondence relationship,
Calculates the charge rate difference value, which is the result of subtracting the charge rate of the battery at the start of charging from the charge rate of the battery at the end of charging, and the current integrated value, which is the integrated value of the current flowing through the battery during charging. Then, the estimation unit that estimates the result of dividing the current integrated value by the charge rate difference value as the full charge capacity of the battery, and
When the discharge capacity difference of capacity of the battery before discharge and capacity of the battery after discharge is at least the threshold value, before Symbol charge rate before Symbol for the discharge point where the open circuit voltage corresponding battery cell determined to be present on the SOC-OCV curve, the charging capacity difference between the capacitance of the battery before charging and capacity of the battery after charging is equal to or greater than the threshold value, the charging rate of the previous SL cells before A determination unit that determines that a point corresponding to the open circuit voltage of the battery exists on the charging SOC-OCV curve, and
With
The estimation unit
It is said that there is a point on the discharge SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the charging rate of the battery is set with reference to the SOC-OCV curve for discharging. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery at the end of charging is defined as the charging rate of the battery at the end of charging.
It is said that there is a point on the charging SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging SOC-OCV curve for charging is referred to, and the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the above. A battery full charge capacity estimation device , wherein the charge rate corresponding to the open circuit voltage of the battery at the end of charging is set as the charge rate of the battery at the end of charging with reference to the SOC-OCV curve for charging. A charging SOC-OCV curve showing the correspondence between the battery charge rate obtained after charging the battery and the open circuit voltage of the battery, and the charge rate obtained after the battery is discharged and the open circuit voltage. A storage unit that stores the SOC-OCV curve for discharge showing the correspondence relationship,
Calculates the charge rate difference value, which is the result of subtracting the charge rate of the battery at the start of charging from the charge rate of the battery at the end of charging, and the current integrated value, which is the integrated value of the current flowing through the battery during charging. Then, the estimation unit that estimates the result of dividing the current integrated value by the charge rate difference value as the full charge capacity of the battery, and
A determination unit for determining whether or not a point corresponding to the charge rate of the battery and the open circuit voltage of the battery exists on the SOC-OCV curve for discharge or the SOC-OCV curve for charging.
With
The determination unit is that the difference in charge capacity between the capacity of the battery after charging and the capacity of the battery before charging corresponds to the charge rate of the battery and the open circuit voltage of the battery. If it is a capacity difference than necessary to transition from the state present on OCV curve state present in the charging SOC-OCV on the curve, and the open circuit voltage of the charging rate and the previous SL cells before SL cells It is determined that the corresponding point exists on the charging SOC-OCV curve, and it is determined that the corresponding point exists on the charging SOC-OCV curve.
The estimation unit
It is said that there is a point on the discharge SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the charging rate of the battery is set with reference to the SOC-OCV curve for discharging. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery at the end of charging is defined as the charging rate of the battery at the end of charging.
It is said that there is a point on the charging SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging SOC-OCV curve for charging is referred to, and the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the above. A battery full charge capacity estimation device , wherein the charge rate corresponding to the open circuit voltage of the battery at the end of charging is set as the charge rate of the battery at the end of charging with reference to the SOC-OCV curve for charging. A charging SOC-OCV curve showing the correspondence between the battery charge rate obtained after charging the battery and the open circuit voltage of the battery, and the charge rate obtained after the battery is discharged and the open circuit voltage. A storage unit that stores the SOC-OCV curve for discharge showing the correspondence relationship,
Calculates the charge rate difference value, which is the result of subtracting the charge rate of the battery at the start of charging from the charge rate of the battery at the end of charging, and the current integrated value, which is the integrated value of the current flowing through the battery during charging. Then, the estimation unit that estimates the result of dividing the current integrated value by the charge rate difference value as the full charge capacity of the battery, and
A determination unit for determining whether or not a point corresponding to the charge rate of the battery and the open circuit voltage of the battery exists on the SOC-OCV curve for discharge or the SOC-OCV curve for charging.
With
The estimation unit
It is said that there is a point on the discharge SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the charging rate of the battery is set with reference to the SOC-OCV curve for discharging. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery at the end of charging is defined as the charging rate of the battery at the end of charging.
It is said that there is a point on the charging SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging SOC-OCV curve for charging is referred to, and the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the above. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery at the end of charging is defined as the charging rate of the battery at the end of charging.
The point corresponding to the charge rate of the battery at the start of estimation and the start of charging and the open circuit voltage of the battery at the start of charging is on the discharge SOC-OCV curve or the charging SOC-OCV. If it is determined that whether present on the curve is not known by the determining unit, before Symbol battery charging rate and the previous SL open circuit voltage and is on the charging SOC-OCV curve points corresponding battery In the charging suspension of the battery after charging the battery until it becomes present, the charging SOC-OCV curve for charging is referred to, and the charging rate corresponding to the open circuit voltage of the battery during the charging suspension is charged. The charge rate of the battery at the start is used, and after charging the battery after resuming charging of the battery, the SOC-OCV curve for charging is referred to, and the open circuit voltage of the battery after charging is used. A battery full charge capacity estimation device, characterized in that the corresponding charge rate is the charge rate of the battery at the end of charging. A charging SOC-OCV curve showing the correspondence between the battery charge rate obtained after charging the battery and the open circuit voltage of the battery, and the charge rate obtained after the battery is discharged and the open circuit voltage. A storage unit that stores the SOC-OCV curve for discharge showing the correspondence relationship,
Calculates the charge rate difference value, which is the result of subtracting the charge rate of the battery at the start of charging from the charge rate of the battery at the end of charging, and the current integrated value, which is the integrated value of the current flowing through the battery during charging. Then, the estimation unit that estimates the result of dividing the current integrated value by the charge rate difference value as the full charge capacity of the battery, and
A determination unit for determining whether or not a point corresponding to the charge rate of the battery and the open circuit voltage of the battery exists on the SOC-OCV curve for discharge or the SOC-OCV curve for charging.
A control unit for controlling the charging and discharging of the battery,
With
The estimation unit
It is said that there is a point on the discharge SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the charging rate of the battery is set with reference to the SOC-OCV curve for discharging. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery at the end of charging is defined as the charging rate of the battery at the end of charging.
It is said that there is a point on the charging SOC-OCV curve where the charge rate of the battery at the start of estimation of the full charge capacity and the open circuit voltage of the battery at the start of charging correspond to each other. When determined by the determination unit, the charging SOC-OCV curve for charging is referred to, and the charging rate corresponding to the open circuit voltage of the battery at the start of charging is set as the charging rate of the battery at the start of charging, and the above. With reference to the charging SOC-OCV curve, the charging rate corresponding to the open circuit voltage of the battery at the end of charging is defined as the charging rate of the battery at the end of charging.
The storage unit internally divides the line segment between the charging SOC-OCV curve and the discharging SOC-OCV curve at a predetermined internal dividing point, and the internal division ratio and the capacity of the battery after charging. Charging internal division ratio information indicating the correspondence relationship between the battery and the capacity of the battery before charging, and the internal division ratio, the capacity of the battery before discharging, and the capacity of the battery after discharging. Stores the internal division ratio information for discharge, which indicates the correspondence with the difference in discharge capacity of
Wherein, at the start of charging the battery by the charger, on the said SOC-OCV curve and the open circuit voltage that corresponds for the discharge of the battery during charging rate and the charging start of the battery during charging start When it does not exist, the internal division ratio at the start of charging is obtained from the traveling history of the vehicle on which the battery is mounted, and the battery is charged using the obtained internal division ratio and the internal division ratio information for charging. The difference in charging capacity required until the point corresponding to the rate and the open circuit voltage of the battery exists on the SOC-OCV curve for charging is obtained, and the obtained difference in charging capacity is charged. , A battery full charge capacity estimation device, characterized in that charging of the battery is suspended.

Images