JP2019052900A - Battery pack - Google Patents

Abstract

To estimate, with a high degree of accuracy, the charging rate of a battery even when the current flowing to a battery is so small as to be undetectable by a current detection unit when a vehicle stops running.SOLUTION: When a vehicle Ve stops running, at least one of the self-discharge current value of a battery B and a dark current value flowing from the battery B to an auxiliary machine is integrated by the stopping time of the vehicle Ve and accordingly a current capacity difference is obtained. When the current capacity difference is greater than or equal to a threshold Cth, an SOC (State Of Charge)-OCV (Open Circuit Voltage) curve for charging or an SOC-OCV curve for discharging is referred to and a charging rate that corresponds to the current open-circuit voltage is estimated as a current charging rate; when the current capacity difference is less than the threshold Cth, internal ratio information is referred to, an internal ratio that corresponds to the current capacity difference is obtained, and a current charging rate is estimated using the found internal ratio, the current open-circuit voltage, the SOC-OCV curve for charging and the SOC-OCV curve for discharging.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery pack mounted on a vehicle.

  As a battery pack mounted on a vehicle, when the capacity difference determined by the current flowing through the battery during charging / discharging is less than a threshold value, the SOC for charging indicating the correspondence between the charging rate of the battery after charging and the open circuit voltage With reference to the OCV curve, a first charging rate corresponding to the current open circuit voltage of the battery is obtained, and a discharging SOC-OCV curve indicating a correspondence relationship between the charging rate of the battery after discharge and the open circuit voltage is obtained. Reference is made to the second charge rate corresponding to the current open circuit voltage of the battery, and the intersection of the first and second charge rates and the open circuit voltage and the charge rate of battery B is the SOC- Some estimate the current battery charge rate using an internal ratio indicating how far away from the OCV curve or the discharging SOC-OCV curve. For example, see Patent Document 1. For related technology, see Patent Document 2, for example. Note that the battery is a battery having a large polarization and requiring a long time for depolarization, such as a lithium ion battery employing a SiO negative electrode.

Japanese Patent Application No. 2017-032779 Special table 2009-519701

  However, in the battery pack, when the vehicle is stopped, if the current flowing through the battery is so small that it cannot be detected by the current detector, the capacity difference cannot be grasped. There is a concern that it cannot be determined whether or not there is, and the estimation accuracy of the charging rate is lowered.

  An object of one aspect of the present invention is to accurately estimate the battery charging rate even when the current flowing through the battery is too small to be detected by the current detection unit when the vehicle is stopped. It is to provide a battery pack that can.

The battery pack which is one form which concerns on this invention is provided with a memory | storage part and a charge rate estimation part.
The storage unit is a SOC-OCV curve for charging indicating the correspondence between the battery charging rate obtained after charging the battery and the open circuit voltage of the battery, and the correspondence between the charging rate obtained after battery discharging and the open circuit voltage. The discharge SOC-OCV curve shown, the internal ratio when dividing the line segment between the charge SOC-OCV curve and the discharge SOC-OCV curve at a predetermined internal dividing point, and at the start of charge / discharge The internal ratio information indicating the correspondence between the capacity of the battery and the capacity difference between the capacity of the battery at the end of charging and discharging is stored.

  When the current capacity difference is equal to or greater than the threshold, the charge rate estimation unit refers to the charge SOC-OCV curve or the discharge SOC-OCV curve, and calculates the charge rate corresponding to the current open circuit voltage as the current charge. Estimate as a rate.

  In addition, when the current capacity difference is less than the threshold, the charging rate estimation unit obtains an internal ratio corresponding to the current capacity difference with reference to the internal ratio information, and the calculated internal ratio and the current The current charging rate is estimated using the open circuit voltage, the SOC-OCV curve for charging, and the SOC-OCV curve for discharging.

  In addition, when the vehicle equipped with the battery is stopped traveling, the charging rate estimation unit determines at least one of the battery self-discharge current value and the dark current value flowing from the battery to the auxiliary device as the vehicle stop time. The current capacity difference is obtained by integration.

  According to the present invention, in the battery pack mounted on the vehicle, even when the current flowing through the battery is too small to be detected by the current detection unit when the vehicle is stopped, the charging rate of the battery Can be estimated with high accuracy.

It is a figure which shows an example of the battery pack of embodiment. It is a figure which shows an example of the SOC-OCV curve for charge, and the SOC-OCV curve for discharge. It is a figure which shows an example of internal ratio information. It is a flowchart which shows an example of a 1st charge rate estimation process. It is a figure for demonstrating an example of the estimation method of a charging rate. It is a figure for demonstrating the other example of the estimation method of a charging rate. It is a flowchart which shows an example of a 2nd charge rate estimation process. It is a figure which shows an example of the change of the charging rate of a battery.

Hereinafter, embodiments will be described in detail with reference to the drawings.
Drawing 1 is a figure showing an example of a battery pack of an embodiment.
A battery pack 1 shown in FIG. 1 is mounted on a vehicle Ve (for example, an engine vehicle or a hybrid vehicle), and includes a battery B, a relay Re, a current detection unit 2, a voltage detection unit 3, a storage unit 4, And a charging rate estimation unit 5.

The voltage detection unit 3 and the charging rate estimation unit 5 are auxiliary devices provided inside the battery pack 1 and are driven by electric power supplied from the battery B.
In addition to the battery pack 1, the vehicle Ve includes a travel control unit 6, a first load control unit 7, and a second load control unit 8.

The travel control unit 6, the first load control unit 7, and the second load control unit 8 are auxiliary devices provided outside the battery pack 1, and are driven by electric power supplied from the battery B.
The traveling control unit 6 is, for example, an ECU (Electronic Control Unit) that controls the operation of the entire vehicle Ve. When the vehicle Ve is an engine vehicle, the traveling vehicle is an EFI (Electrical Fuel Injection) -ECU, and the vehicle Ve is a hybrid vehicle. In some cases, HV (Hybrid Vehicle) -ECU is used.

  The first load control unit 7 is an ECU that performs operation control of a load that needs to continue to operate when the vehicle Ve is stopped traveling, such as an immobilizer, for example. The case where the vehicle Ve is stopped running is, for example, a case where the ignition key is off.

The second load control unit 8 is an ECU, such as an air conditioner, that performs operation control of a load that does not need to continue to operate when the vehicle Ve is stopped running.
The battery B includes, for example, one or more secondary batteries (such as a lithium ion battery, a nickel metal hydride battery, or an electric double layer capacitor).

  The relay Re is constituted by, for example, an electromagnetic relay, and is an auxiliary machine (for example, the travel control unit 6, the first load control unit 7, and the second load control unit 8) provided outside the battery B and the battery pack 1. ) Is connected between.

For example, when the relay Re is in the closed state and the vehicle Ve is running, the battery B is charged when power is supplied from the alternator (not shown) to the battery B.
Further, when the relay Re is in the closed state and the vehicle Ve is stopped running, the battery B is charged when power is supplied to the battery B from a battery or charger of a rescue vehicle (not shown). The

  Further, when the relay Re is in a closed state and the vehicle Ve is traveling, the voltage detection unit 3, the charging rate estimation unit 5, the traveling control unit 6, the first load control unit 7, from the battery B, And electric power is supplied to the 2nd load control part 8, and the battery B is discharged.

  Further, when the relay Re is in the closed state and the vehicle Ve is stopped traveling, the voltage detection unit 3, the charging rate estimation unit 5, the traveling control unit 6, and the first load control unit from the battery B are stopped. 7 is supplied with electric power, and the battery B is discharged.

Further, when the relay Re is in the open state and the vehicle Ve is stopped, power is supplied from the battery B to the voltage detection unit 3 and the charge rate estimation unit 5, and the battery B is discharged.
When the vehicle Ve is stopped running, the current flowing through the battery B due to the self-discharge of the battery B is so small that it cannot be detected by the current detection unit 2, and is hereinafter referred to as a self-discharge current value. .

  Further, when the vehicle Ve is stopped traveling, and the battery B is used to maintain the sleep state from the battery B to the voltage detection unit 3, the charging rate estimation unit 5, the traveling control unit 6, and the first load control unit 7. When electric power is supplied, the current flowing through the battery B is so small that it cannot be detected by the current detection unit 2, and is hereinafter referred to as a dark current value.

The current detection unit 2 is configured by, for example, a shunt resistor or a Hall element, and detects the current I flowing through the battery B.
The voltage detection unit 3 is a monitoring ECU that detects the voltage V of the battery B. For example, the CPU (Central Processing Unit), a multi-core CPU, or a programmable device (FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device)) Etc.).

  The storage unit 4 is configured by, for example, a ROM (Read Only Memory) or a RAM (Random Access Memory), and has a SOC-OCV curve for charging, a SOC-OCV curve for discharging, and a correspondence relationship between a capacity difference and an internal ratio. The internal ratio information shown is stored.

FIG. 2 is a diagram illustrating an example of a charging SOC-OCV curve and a discharging SOC-OCV curve stored in the storage unit 4. 2, the vertical axis represents the open circuit voltage of the battery B, and the horizontal axis represents the charging rate of the battery B.

  Battery B has a large polarization and requires a long time for depolarization. Correspondence between charge rate SOC (State Of Charge) and open circuit voltage OCV (Open Circuit Voltage) of battery B obtained after charging The SOC-OCV curve for charging indicating the relationship and the SOC-OCV curve for discharging indicating the corresponding relationship between the charging rate SOC of the battery B obtained after discharging and the open circuit voltage OCV have different characteristics from each other To do. The charge rate SOC indicates the ratio [%] of the current capacity of the battery B to the full charge capacity of the battery B. In addition, the SOC-OCV curve for charging and the SOC-OCV curve for discharging are acquired by, for example, experiments or simulations, and are acquired after a predetermined time T1 has elapsed since the charging or discharging of the battery B is completed. And

  FIG. 3A is a diagram illustrating an example of internal division information stored in the storage unit 4. In addition, the vertical axis | shaft of the graph shown to Fig.3 (a) shows an internal ratio, and the horizontal axis has shown the capacity | capacitance difference. Further, the curve shown in FIG. 3A shows internal ratio information. FIG. 3B and FIG. 3C are diagrams showing the relationship between the SOC-OCV curve for charging, the SOC-OCV curve for discharging, and the internal ratio p. In the graphs shown in FIGS. 3B and 3C, the vertical axis represents the open circuit voltage, and the horizontal axis represents the charging rate. Moreover, the true charge rate after charge shown in FIG. 3B is a value acquired by, for example, experiment or simulation, and the intersection d1 between the open circuit voltage of the battery B after discharge and the charge rate is for discharge. The charging rate is obtained when charging for a predetermined capacity from a state on the SOC-OCV curve. The open circuit voltage after the elapse of the predetermined time T1 shown in FIG. 3B is a value acquired by, for example, experiment or simulation, and is acquired after the elapse of the predetermined time T1 after charging a predetermined capacity. Open circuit voltage. Further, the true charge rate after discharge shown in FIG. 3C is a value obtained by, for example, experiment or simulation, and the intersection c1 between the open circuit voltage of the battery B after charge and the charge rate is for charging. The charging rate is obtained when discharging a predetermined capacity from the state on the SOC-OCV curve. The open circuit voltage after the elapse of the predetermined time T1 shown in FIG. 3C is a value acquired by, for example, experiment or simulation, and is acquired after the elapse of the predetermined time T1 after discharging a predetermined capacity. Open circuit voltage.

  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 Cth shown in FIG. 3A, the battery after charging corresponding to the open circuit voltage of the battery B after charging. The charging rate of B matches the charging rate SOC shown in the charging SOC-OCV curve shown in FIG. That is, when battery B is sufficiently charged, the intersection of the open circuit voltage of battery B after charging and the charging rate is on the SOC-OCV curve for charging shown in FIG.

  Further, when the capacity difference between the capacity of the battery B before discharging and the capacity of the battery B after discharging is equal to or greater than the threshold Cth shown in FIG. 3A, the discharge corresponding to the open circuit voltage OCV of the battery B after discharging. The charging rate of the later battery B matches the charging rate SOC shown in the discharging SOC-OCV curve shown in FIG. That is, when the battery B is sufficiently discharged, the intersection between the open circuit voltage and the charging rate of the battery B after discharging is on the discharging SOC-OCV curve shown in FIG.

  Thus, in the case where the battery B is sufficiently charged / discharged, no matter what value the capacity of the battery B before charging / discharging or the capacity of the battery B after charging / discharging is, Since the intersection of the open circuit voltage and the charging rate is on one of the charging SOC-OCV curve and the discharging SOC-OCV curve shown in FIG. 2, the charging SOC-OCV curve and the discharging SOC- shown in FIG. Using either one of the OCV curves, the current charging rate can be accurately estimated.

  Further, the internal ratio shown in the internal ratio information shown in FIG. 3A is, for example, as shown in FIG. 3B, where the intersection d1 between the open circuit voltage of the battery B after discharge and the charging rate is A predetermined time T1 after charging for a predetermined capacity (a value smaller than the threshold Cth, for example, the capacity difference a shown in FIG. 3A) from a state on the SOC-OCV curve for discharge. With the open circuit voltage after the lapse of time as a predetermined internal dividing point, the true charge rate and discharge for battery B after being charged by a predetermined charge rate from the state where the intersection d1 is on the discharge SOC-OCV curve The first open circuit voltage corresponding to the intersection with the SOC-OCV curve and the true charging of the battery B after being charged by a predetermined charging rate from the state where the intersection d1 is on the discharging SOC-OCV curve Between the rate and the second open circuit voltage corresponding to the intersection of the SOC-OCV curve for charging Line segments, the first open-circuit voltage p as a reference: the internal ratio p when internally divides the (1-p).

  Alternatively, the internal ratio shown in the internal ratio information shown in FIG. 3A is, for example, an intersection c1 between the open circuit voltage of the battery B after charging and the charging rate, as shown in FIG. 3C. A predetermined time T1 after discharging for a predetermined capacity (a value smaller than the threshold Cth, for example, the capacity difference a shown in FIG. 3A) from the state on the SOC-OCV curve for charging. With the open circuit voltage after the elapse of time as a predetermined internal dividing point, the true charging rate and charging for the battery B after being discharged by a predetermined charging rate from the state where the intersection c1 is on the charging SOC-OCV curve The third open circuit voltage corresponding to the intersection with the SOC-OCV curve and the true charging of battery B after the intersection c1 is discharged by a predetermined charging rate from the state where the intersection c1 is on the charging SOC-OCV curve The fourth open circuit voltage corresponding to the intersection of the rate and the SOC-OCV curve for discharge The line segment, p is based on the third open circuit voltage: an internal ratio p when internally divides the (1-p).

  When the battery B is charged from a state in which the point corresponding to the charge rate of the battery B after discharge and the open circuit voltage exists on the discharge SOC-OCV curve, and the capacity of the battery B after charge 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 ratio obtained from the internal ratio information is the SOC-OCV curve for charging and the discharge as shown in FIG. In the line segment in the open circuit voltage axis direction between the SOC-OCV curve for the battery and the distance d2 between the open circuit voltage and the charging rate of the battery B after charging, how far away from the discharge SOC-OCV curve is shown. Yes.

  When the battery B is discharged from a state in which the charging rate of the battery B after charging corresponds to the open circuit voltage on the SOC-OCV curve for charging, and the capacity of the battery B before discharging When the capacity difference between the capacity of the battery B after discharge and the capacity of the battery B is less than the threshold value Cth, the internal ratio obtained from the internal ratio information is as shown in FIG. In the line segment in the open circuit voltage axis direction between the SOC-OCV curve for the battery and the distance c2 between the open circuit voltage and the charge rate of the battery B after the discharge, how far away from the SOC-OCV curve for the charge is shown Yes.

  Thus, when the capacity difference before and after charging or before and after discharging is less than the threshold Cth, the internal ratio is determined from the capacity difference before and after charging or before and after discharging, and the SOC-OCV curve for charging is calculated from the determined internal ratio. It is possible to uniquely determine the intersection of the open circuit voltage and the charging rate existing between the discharging SOC-OCV curve.

  The charge rate estimation unit 5 illustrated in FIG. 1 is a control ECU that controls the charging or discharging of the battery B, and includes, for example, a CPU, a multi-core CPU, or a programmable device (FPGA, PLD, or the like).

In addition, the charging rate estimation unit 5 performs a first charging rate estimation process at the end of charging of the battery B or at the end of discharging of the battery B.
Moreover, the charging rate estimation part 5 performs a 2nd charging rate estimation process for every predetermined time T3 progress, when the vehicle Ve has stopped driving | running | working. For example, when the charging rate estimation unit 5 receives information indicating that the vehicle Ve has stopped running from the driving control unit 6, the charging rate estimation unit 5 determines that the driving stop of the vehicle Ve has started, and indicates that the vehicle Ve has started to run. Is received from the traveling control unit 6, it is determined that the traveling stop of the vehicle Ve has ended.

  In addition, when the vehicle Ve is stopped traveling, the charging rate estimation unit 5 switches the relay Re from the closed state to the open state when the voltage V detected by the voltage detection unit 3 or the charging rate of the battery B becomes equal to or less than the threshold value. To do. Thereby, when the vehicle Ve is stopped running, the battery B can be prevented from being overdischarged due to the self-discharge current value or the dark current value. The charging rate estimation unit 5 keeps the relay Re closed when the voltage V of the battery B or the charging rate of the battery B is larger than the threshold value.

  FIG. 4 is a flowchart illustrating an example of the first charging rate estimation process. FIG. 4 shows the charge rate estimation unit 5 after the discharge of the battery B is started from the state where the intersection of the open circuit voltage and the charge rate of the battery B after charging is on the charging SOC-OCV curve. Of the battery B after the start of charging of the battery B from the state where the intersection of the open circuit voltage and the charging rate of the battery B after discharging is on the discharging SOC-OCV curve 5 shows an example of the operation.

  First, when the charging or discharging ends (S41: Yes) and the predetermined time T2 has elapsed (S42: Yes), the charging rate estimation unit 5 determines whether or not the current capacity difference is greater than or equal to the threshold Cth (S43). ). The predetermined time T2 may be the same time as the predetermined time T1 or may be a different time. Further, for example, the charging rate estimation unit 5 is detected by the current detection unit 2 at each detection timing from the start of charging of the battery B to the end of charging or from the start of discharging of the battery B to the end of discharging. The integrated value ΔI [Ah] of the current I is obtained, and the obtained integrated value ΔI is set as the current capacity difference. Alternatively, for example, the charging rate estimation unit 5 calculates ΔV = | voltage of the battery B before charging / discharging−voltage of the battery B after charging / discharging |, and ΔV that is the calculation result is set as the current capacity difference. . Alternatively, for example, the charging rate estimation unit 5 calculates ΔSOC [%] = (| capacity [Ah] of the battery B before charging / discharging−capacity [Ah] of the battery B after charging / discharging | / full charging capacity of the battery B [ Ah]) × 100 and ΔSOC, which is the calculation result, is set as the current capacity difference.

  Next, when the current capacity difference is greater than or equal to the threshold Cth (S43: Yes), the charging rate estimation unit 5 acquires the current open circuit voltage (S44), and the charging SOC stored in the storage unit 4 The charging rate SOC corresponding to the current open circuit voltage is obtained with reference to the -OCV curve or the discharging SOC-OCV curve, and the obtained charging rate SOC is estimated as the current charging rate (S45).

  For example, the charging rate estimation unit 5 is detected by the voltage detection unit 3 when the relay Re is in the closed state and the current I detected by the current detection unit 2 is zero or substantially zero. The voltage V is acquired as the current open circuit voltage of the battery B.

  For example, the charging rate estimation unit 5 opens the battery B when the capacity difference (current capacity difference) between the capacity of the battery B at the end of charging and the capacity of the battery B at the start of charging is equal to or greater than a threshold Cth. It is determined that an intersection between the circuit voltage and the charging rate exists on the charging SOC-OCV curve, and the charging corresponding to the current open circuit voltage is referred to with reference to the charging SOC-OCV curve shown in FIG. The rate SOC is obtained, and the obtained charge rate SOC is estimated as the current charge rate. As described above, when the capacity difference between the capacity of the battery B at the end of charging and the capacity of the battery B at the start of charging is equal to or greater than the threshold Cth, the current charging rate corresponding to the current open circuit voltage is all SOC for charging. Since it matches the charging rate SOC shown in the -OCV curve, the current charging rate can be estimated uniquely from the current open circuit voltage.

  For example, the charging rate estimation unit 5 opens the battery B when the capacity difference (current capacity difference) between the capacity of the battery B at the start of discharge and the capacity of the battery B at the end of discharge is equal to or greater than the threshold Cth. It is determined that the intersection of the circuit voltage and the charging rate exists on the discharging SOC-OCV curve, and the charging corresponding to the current open circuit voltage is performed with reference to the discharging SOC-OCV curve shown in FIG. The rate SOC is obtained, and the obtained charge rate SOC is estimated as the current charge rate. Thus, when the capacity difference between the capacity of the battery B at the start of discharge and the capacity of the battery B at the end of discharge is equal to or greater than the threshold value Cth, the current charging rate corresponding to the current open circuit voltage is all SOC for discharging. Since it matches the charging rate SOC shown in the -OCV curve, the current charging rate can be estimated uniquely from the current open circuit voltage.

  On the other hand, when the charge rate estimation unit 5 determines that the current capacity difference is less than the threshold value Cth (S43: No), the intersection of the open circuit voltage of the battery B and the charge rate is the SOC-OCV curve for charging and the discharge. The internal ratio is determined using the current capacity difference (S46). For example, the charging rate estimation unit 5 refers to the internal ratio information shown in FIG. 3A and obtains an internal ratio corresponding to the current capacity difference.

Next, the charging rate estimation unit 5 acquires the current open circuit voltage OCV after the predetermined time T2 has elapsed in S42 (S47).
Then, the charging rate estimation unit 5 estimates the current charging rate by using the internal ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve (S48). .

  For example, after the battery B is charged, when the current capacity difference is less than the threshold value Cth, the charging rate estimation unit 5 performs the charging SOC-OCV curve and the discharging SOC-OCV curve as shown in FIG. Of the line segment in the open circuit voltage axis direction between the internal dividing point obtained by the internal division ratio p on the basis of the SOC-OCV curve for charging and the current open circuit voltage. The corresponding charging rate SOC1 is estimated as the current charging rate.

  Alternatively, for example, when the current capacity difference is less than the threshold value Cth after the battery B is discharged, the charging rate estimation unit 5 may charge the SOC-OCV curve for charging and the SOC- for discharging as shown in FIG. Of the line segments in the open circuit voltage axis direction between the OCV curve, the line when the internal dividing point determined by the internal division ratio p on the basis of the discharge SOC-OCV curve and the current open circuit voltage coincide with each other The charging rate SOC2 corresponding to the minute is estimated as the current charging rate.

  Alternatively, for example, when the current capacity difference is less than the threshold value Cth after the battery B is charged, the charging rate estimation unit 5 may charge the SOC-OCV curve for charging and the SOC- for discharging as shown in FIG. The charge rate SOC1 corresponding to the internal dividing point determined by the internal division ratio p with respect to the SOC-OCV curve for charging in the line segment in the charge rate axis direction corresponding to the current open circuit voltage between the OCV curve, Estimate the current charging rate. In other words, in FIG. 6A, the length of the point on the charge SOC-OCV curve corresponding to the current open circuit voltage and the internal dividing point, and the discharge SOC-OCV curve corresponding to the current open circuit voltage. The charging rate SOC1 corresponding to the inner dividing point where the length ratio between the upper point and the inner dividing point becomes equal to the inner dividing ratio p is estimated as the current charging rate.

  Alternatively, for example, when the current capacity difference is less than the threshold value Cth after the battery B is discharged, the charging rate estimation unit 5 may charge the SOC-OCV curve for charging and the SOC- for discharging as shown in FIG. The charge rate SOC2 corresponding to the internal dividing point determined by the internal division ratio p with reference to the SOC-OCV curve for discharge in the line segment in the charge rate axis direction corresponding to the current open circuit voltage between the OCV curve, Estimate the current charging rate. In other words, in FIG. 6B, the length of the point on the discharging SOC-OCV curve corresponding to the current open circuit voltage and the internal dividing point, and the charging SOC-OCV curve corresponding to the current open circuit voltage. The charging rate SOC2 corresponding to the inner dividing point where the length ratio between the upper point and the inner dividing point becomes equal to the inner dividing ratio p is estimated as the current charging rate.

  Thus, in the battery pack 1 of the embodiment, the intersection of the open circuit voltage and the charging rate of the battery B after charging / discharging (= the point where the charging rate and the open circuit voltage of the battery B correspond) is the SOC for charging. When it exists between the OCV curve and the discharging SOC-OCV curve, the internal ratio is obtained from the capacity difference before and after charging or before and after discharging, and the intersection of the open circuit voltage and the charging rate is uniquely determined from the obtained internal ratio. Therefore, the charging rate can be accurately estimated from the intersection of the obtained open circuit voltage and the charging rate. Therefore, the estimation accuracy of the charging rate can be improved in the battery B in which the polarization is large and it takes a long time to eliminate the polarization.

  Further, in the battery pack 1 of the embodiment, when the charging or discharging of the battery B is completed when the vehicle Ve is stopped, the intersection of the open circuit voltage and the charging rate of the battery B is on the charging SOC-OCV curve. Therefore, it can be determined that it exists on any one of the SOC-OCV curve for discharging and between the SOC-OCV curve for charging and the SOC-OCV curve for discharging.

FIG. 7 is a flowchart illustrating an example of the second charging rate estimation process.
First, the charging rate estimation unit 5 has an intersection between the open circuit voltage of the battery B and the charging rate on the discharging SOC-OCV curve when the discharging of the battery B is completed when the vehicle Ve is stopped. If it is determined (S71: Yes), the current open circuit voltage is acquired (S72), and the charge corresponding to the current open circuit voltage is referenced with reference to the discharging SOC-OCV curve stored in the storage unit 4 The rate SOC is obtained, and the obtained charge rate SOC is estimated as the current charge rate (S73). As described above, when the discharge of the battery B is completed when the vehicle Ve is stopped, when the intersection of the open circuit voltage of the battery B and the charging rate exists on the discharging SOC-OCV curve, Even if the battery B is discharged until the capacity difference becomes equal to or greater than the threshold value Cth when the vehicle Ve is stopped, the intersection of the open circuit voltage and the charging rate of the battery B is on the discharging SOC-OCV curve. Since it continues to exist, the charging rate corresponding to the open circuit voltage can be uniquely obtained with reference to the discharging SOC-OCV curve.

  In addition, when the charging of the battery B is finished when the vehicle Ve is stopped, the charging rate estimation unit 5 has an intersection between the open circuit voltage of the battery B and the charging rate on the charging SOC-OCV curve. (S71: No, S74: Yes), the current capacity difference is calculated by integrating (multiplying) at least one of the self-discharge current value and the dark current value of the battery B with the stop time of the vehicle Ve. Obtain (S75). That is, the charging rate estimation unit 5 sets the current capacity difference to the current capacity difference = the self-discharge current value × the stop time of the vehicle Ve. Or the charging rate estimation part 5 makes the present capacity difference the calculation result of the present capacity difference = dark current value x stop time of the vehicle Ve. Or the charging rate estimation part 5 makes the present capacity | capacitance difference the calculation result of the present capacity | capacitance difference = (self-discharge current value + dark current value) x stop time of the vehicle Ve. It is assumed that the self-discharge current value is stored in the storage unit 4.

  On the other hand, when the charging or discharging of the battery B is completed when the vehicle Ve is stopped, the charging rate estimation unit 5 determines that the intersection between the open circuit voltage of the battery B and the charging rate is the charging SOC-OCV curve and the charging. (S71: No, S74: No), if at least one of the self-discharge current value and the dark current value of the battery B is integrated with the stop time of the vehicle Ve (S71: No, S74: No) The current capacity difference is obtained by adding the value obtained by multiplication) and the capacity difference (= the integrated value ΔI of the current I detected from the start of charge / discharge until the end of charge / discharge) obtained when the vehicle Ve stops traveling. Is obtained (S76).

Here, a dark current calculation example will be described.
<Example of calculation of dark current value (1)>
The charging rate estimation unit 5 receives a current value necessary for the operation of an auxiliary device provided outside the battery pack 1 when the vehicle Ve is stopped from traveling from the traveling control unit 6, and uses the received current value. The dark current value.

  For example, the first current value necessary for the voltage detection unit 3 to operate when the vehicle Ve is stopped traveling is set to 0.25 [mA], and the charging rate estimation unit 5 when the vehicle Ve is stopped traveling. Is set to 0.75 [mA], and the third current value required for the travel controller 6 to operate when the vehicle Ve is stopped is set to 0.75. [MA], and a fourth current value required for the first load control unit 7 to operate when the vehicle Ve is stopped running is 0.25 [mA].

  In this case, the charging rate estimation unit 5 receives the third current value 0.75 [mA] and the fourth current value 0.25 [mA] from the travel control unit 6, and the dark current value = (first 1. Calculation result of current value 0.25 [mA] + second current value 0.75 [mA] + third current value 0.75 [mA] + fourth current value 0.25 [mA]) 00 [mA] is a dark current value.

  Alternatively, the charging rate estimation unit 5 receives the total value 1.00 [mA] of the third current value 0.75 [mA] and the fourth current value 0.25 [mA] from the travel control unit 6, Dark current value = (first current value 0.25 [mA] + second current value 0.75 [mA] + total value 1.00 [mA]) calculation result 2.00 [mA] The current value.

  In this way, the travel control unit 6 outside the battery pack 1 performs the total processing of the current values necessary for the operation of the auxiliary equipment provided outside the battery pack 1 when the vehicle Ve is stopped traveling. Therefore, the calculation processing load of the charging rate estimation unit 5 inside the battery pack 1 can be reduced. In addition, the charging rate estimation unit 5 includes auxiliary devices (travel control unit 6, first load control unit 7, and second load control unit 8 provided outside the battery pack 1 when the vehicle Ve is stopped traveling. ), It is possible to accurately know which of the auxiliary devices (the travel control unit 6 and the first load control unit 7) through which the current flows.

<Dark current value calculation example (2)>
The storage unit 4 stores a reference value of a current flowing from the battery B to an auxiliary device provided outside the battery pack 1.

  The charging rate estimation unit 5 receives a coefficient set for each auxiliary device through which a current flows when the vehicle Ve is stopped from traveling from the traveling control unit 6, and darkens the multiplication result of the received coefficient and the reference value. The current value.

  For example, the storage unit 4 is a reference value of the current that flows from the battery B to the voltage detection unit 3, the charge rate estimation unit 5, the travel control unit 6, and the first load control unit 7 when the vehicle Ve is stopped traveling. It is assumed that 0.5 [mA] is stored. Further, the first coefficient corresponding to the voltage detection unit 3 is 0.5, the second coefficient corresponding to the charging rate estimation unit 5 is 1.5, and the third coefficient corresponding to the travel control unit 6 is 1.5. The fourth coefficient corresponding to the first load control unit 7 is set to 0.5.

  In this case, the charging rate estimation unit 5 receives the third coefficient 1.5 and the fourth coefficient 0.5 from the travel control unit 6, and the dark current value = (first coefficient 0.5 + second coefficient). The calculation result 2.0 [mA] of 1.5 + the third coefficient 1.5 + the fourth coefficient 0.5) × the reference value 0.5 is the dark current.

  Alternatively, the charging rate estimation unit 5 receives the total value 2.0 of the third coefficient 1.5 and the third coefficient 0.5 from the travel control unit 6, and dark current value = (first coefficient 0 0.5 + second coefficient 1.5 + total value 2.0) × calculation result 2.0 [mA] of reference value 0.5 is defined as dark current.

  As described above, since the total processing of the coefficient corresponding to the auxiliary device through which the current flows when the vehicle Ve is stopped traveling can be performed by the traveling control unit 6 outside the battery pack 1, It is possible to reduce the calculation processing load of the charging rate estimation unit 5. In addition, the charging rate estimation unit 5 includes auxiliary devices (travel control unit 6, first load control unit 7, and second load control unit 8 provided outside the battery pack 1 when the vehicle Ve is stopped traveling. ), It is possible to accurately know which of the auxiliary devices (the travel control unit 6 and the first load control unit 7) through which the current flows.

<Example of calculation of dark current value (3)>
The storage unit 4 associates the type of auxiliary equipment provided in the battery pack 1 with the current value flowing through the auxiliary equipment provided in the battery pack 1 when the vehicle Ve is stopped traveling. Is stored.

  The charging rate estimation unit 5 acquires the current value corresponding to the type of the auxiliary device through which the current is flowing when the vehicle Ve is stopped traveling with reference to the first correspondence information, and the acquired current value is The dark current value.

  For example, the storage unit 4 has “A” as information for identifying the voltage detection unit 3 and 0.25 [mA] as a current flowing from the battery B to the voltage detection unit 3 when the vehicle Ve is stopped running. And “B” as information for identifying the charging rate estimation unit 5 and 0.75 [mA] as a current flowing from the battery B to the charging rate estimation unit 5 when the vehicle Ve is stopped traveling Is stored in the first correspondence information.

  In this case, the charging rate estimation unit 5 acquires 0.25 [mA] corresponding to “A” with reference to the first correspondence information, and obtains 0.75 [mA] corresponding to “B” to the first. And the total value 1.00 [mA] of the acquired 0.25 [mA] and 0.75 [mA] is set as a dark current.

<Example of calculation of dark current value (4)>
The storage unit 4 associates a type of an auxiliary machine provided outside the battery pack 1 with a current value flowing through an auxiliary machine provided outside the battery pack 1 when the vehicle Ve is stopped traveling. Is stored.

  The charging rate estimation unit 5 receives the type of the auxiliary device through which the current flows when the vehicle Ve is stopped from traveling from the traveling control unit 6, and receives the current value corresponding to the received type of the auxiliary device as the second value. The current value obtained by referring to the correspondence information is set as the dark current value.

  For example, the storage unit 4 has “C” as information for identifying the travel control unit 6 and 0.75 [mA] as a current flowing from the battery B to the travel control unit 6 when the vehicle Ve is stopped traveling. And “D” as information for identifying the first load control unit 7 and 0.25 as the current flowing from the battery B to the first load control unit 7 when the vehicle Ve is stopped traveling Assume that second correspondence information associated with [mA] is stored.

  In this case, the charging rate estimation unit 5 receives “C” and “D” from the travel control unit 6 and acquires 0.75 [mA] corresponding to “C” with reference to the second correspondence information. , 0.25 [mA] corresponding to “D” is obtained by referring to the second correspondence information, and the total value 1.00 [mA] of the obtained 0.75 [mA] and 0.25 [mA]. ] Is a dark current.

  As described above, since only the identification information corresponding to the auxiliary device through which the current flows when the vehicle Ve is stopped traveling is transmitted from the traveling control unit 6 to the charging rate estimating unit 5, the vehicle Ve is stopped traveling. The amount of data transmitted from the traveling control unit 6 to the charging rate estimation unit 5 can be reduced compared to the configuration in which the current value flowing through the auxiliary machine is transmitted from the traveling control unit 6 to the charging rate estimation unit 5 when In addition, the charging rate estimation unit 5 includes auxiliary devices (travel control unit 6, first load control unit 7, and second load control unit 8 provided outside the battery pack 1 when the vehicle Ve is stopped traveling. ), It is possible to accurately know which of the auxiliary devices (the travel control unit 6 and the first load control unit 7) through which the current flows.

<Example of calculation of dark current value (5)>
The storage unit 4 associates the type of auxiliary equipment provided in the battery pack 1 with the current value flowing through the auxiliary equipment provided in the battery pack 1 when the vehicle Ve is stopped traveling. The second correspondence in which the correspondence information, the type of auxiliary equipment provided outside the battery pack, and the current value flowing through the auxiliary equipment provided outside the battery pack when the vehicle Ve is stopped traveling are associated with each other Store information.

  When the relay Re is in the open state, the charging rate estimation unit 5 acquires a current value corresponding to the type of the auxiliary machine through which the current is flowing when the vehicle Ve is stopped with reference to the first correspondence information. The obtained current value is set as a dark current value.

  In addition, when the relay Re is in the closed state, the charging rate estimation unit 5 receives the type of auxiliary equipment outside the battery pack 1 through which current flows when the vehicle Ve is stopped from traveling from the traveling control unit 6, and the vehicle Ve. The current value corresponding to the type of auxiliary machine in the battery pack 1 through which current flows when the vehicle stops traveling is obtained with reference to the first correspondence information, and the current value corresponding to the received type of auxiliary machine is obtained. It acquires with reference to 2nd correspondence information, and let the total value of those acquired current values be a dark current value.

For example, it is assumed that the storage unit 4 stores the first correspondence information and the second correspondence information.
In this case, the charging rate estimation unit 5 receives “C” and “D” from the travel control unit 6, and acquires 0.25 [mA] corresponding to “A” with reference to the first correspondence information. , 0.75 [mA] corresponding to “B” is acquired with reference to the first correspondence information, and 0.75 [mA] corresponding to “C” is acquired with reference to the second correspondence information. , 0.25 [mA] corresponding to “D” is acquired with reference to the second correspondence information, and the acquired 0.25 [mA], 0.75 [mA], 0.75 [mA], And a total value of 2.00 [mA] of 0.25 [mA] is a dark current.

  Thus, since only the identification information corresponding to the auxiliary device through which current flows when the vehicle Ve is stopped traveling is transmitted from the traveling control unit 6 to the charging rate estimating unit 5, an example of calculating a dark current value ( Similarly to 4), the amount of data transmitted from the traveling control unit 6 to the charging rate estimation unit 5 can be reduced. The charging rate estimation unit 5 can be used when the vehicle Ve is stopped traveling. Among the auxiliary machines (running control unit 6, first load control unit 7, and second load control unit 8) provided outside 1, auxiliary devices through which current flows (running control unit 6 and first load control) It is possible to know exactly which part 7) is. In addition, the charging rate estimation unit 5 can accurately know which auxiliary device through which a current flows when the vehicle Ve is stopped traveling according to the state of the relay Re.

  Next, when the current capacity difference is greater than or equal to the threshold Cth (S77: Yes), the charging rate estimation unit 5 acquires the current open circuit voltage (S72), and the discharging SOC stored in the storage unit 4 The charging rate SOC corresponding to the current open circuit voltage is obtained with reference to the -OCV curve, and the obtained charging rate SOC is estimated as the current charging rate (S73). As described above, when the charging of the battery B is completed when the vehicle Ve is stopped, if the intersection of the open circuit voltage of the battery B and the charging rate exists on the charging SOC-OCV curve, When the vehicle Ve is stopped, when the battery B is discharged until the capacity difference becomes equal to or greater than the threshold value Cth, the intersection of the open circuit voltage and the charging rate of the battery B is on the discharging SOC-OCV curve. Therefore, the charging rate corresponding to the open circuit voltage can be uniquely obtained with reference to the discharging SOC-OCV curve.

  On the other hand, when determining that the current capacity difference is less than the threshold value Cth (S77: No), the charging rate estimation unit 5 obtains an internal ratio using the current capacity difference (S78), and the current open circuit voltage OCV. (S79), and the current charging rate is estimated using the internal ratio, the current open circuit voltage, the SOC-OCV curve for charging, and the SOC-OCV curve for discharging (S80). As described above, when the charging of the battery B is completed when the vehicle Ve is stopped, if the intersection of the open circuit voltage of the battery B and the charging rate exists on the charging SOC-OCV curve, When the vehicle Ve is stopped running, if the capacity difference is less than the threshold value Cth, the intersection of the open circuit voltage of the battery B and the charging rate is the difference between the charging SOC-OCV curve and the discharging SOC-OCV curve. Therefore, the charging rate can be uniquely determined using the internal ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve.

  FIG. 8A is a diagram illustrating an example of a change in the charging rate of the battery B after the vehicle Ve has stopped traveling. In addition, the vertical axis | shaft of the graph shown to Fig.8 (a) shows the charging rate of the battery B, and the horizontal axis has shown time.

  First, when the vehicle Ve stops traveling, the charging rate estimation unit 5 finishes discharging the battery B (time t1), and the capacity difference between the capacity of the battery B before discharging and the capacity of the battery B after discharging is a threshold value. If it is equal to or higher than Cth, the charging rate SOC corresponding to the current open circuit voltage OCV is estimated as the current charging rate with reference to the discharging SOC-OCV curve. Moreover, the charging rate estimation part 5 judges that the intersection of the open circuit voltage of the battery B and a charging rate exists on the SOC-OCV curve for discharge at the time t1.

  After that, when the vehicle Ve is stopped, the discharge of the battery B continues due to the self-discharge current value and the dark current value. Therefore, the intersection of the open circuit voltage of the battery B and the charge rate is the SOC-OCV for discharge. Continuing on the curve.

  Next, when the vehicle Ve is stopped traveling, when the predetermined time T3 has elapsed (time t2), the charging rate estimation unit 5 refers to the discharging SOC-OCV curve and corresponds to the current open circuit voltage. The charging rate is estimated as the current charging rate.

  That is, the charging rate estimation unit 5 is the case where the capacity difference between the capacity of the battery B at the start of discharging and the capacity of the battery B at the end of discharging is equal to or greater than the threshold Cth when the vehicle Ve is stopped running, and When Ve is stopped, the charging rate corresponding to the current open circuit voltage is estimated as the current charging rate with reference to the discharging SOC-OCV curve.

  FIG. 8B is a diagram illustrating another example of the change in the charging rate of the battery B after the vehicle Ve has stopped traveling. In addition, the vertical axis | shaft of the graph shown in FIG.8 (b) shows the charging rate of the battery B, and the horizontal axis has shown time.

  First, when the vehicle Ve stops traveling, the charging rate estimation unit 5 finishes discharging the battery B (time t1), and the capacity difference between the capacity of the battery B before discharging and the capacity of the battery B after discharging is a threshold value. If it is less than Cth, the internal ratio information is referred to determine the internal ratio corresponding to the current capacity difference, the determined internal ratio, the current open circuit voltage OCV, and the SOC-OCV curve for charging. And the present charging rate is estimated using the SOC-OCV curve for discharge. Further, the charging rate estimation unit 5 determines that the intersection of the open circuit voltage of the battery B and the charging rate exists between the charging SOC-OCV curve and the discharging SOC-OCV curve at time t1. To do.

  After that, when the vehicle Ve is stopped, the battery B is discharged by the self-discharge current value and the dark current value. Therefore, the intersection of the open circuit voltage of the battery B and the charging rate is the charging SOC-OCV curve. It exists between the SOC-OCV curve for discharge or on the SOC-OCV curve for discharge.

  Then, when the vehicle Ve is stopped traveling, the charging rate estimation unit 5 passes the predetermined time T3 (time t2), and at least one of the self-discharge current value and the dark current value is determined by the stop time of the vehicle Ve. The current capacity difference is obtained by adding the integrated value and the capacity difference obtained at time t1, and if the capacity difference is less than the threshold Cth, the current capacity difference is referred to by referring to the internal ratio information. The current charging rate is estimated using the determined internal ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve. .

  The charging rate estimation unit 5 obtains the current capacity difference by integrating at least one of the self-discharge current value and the dark current value with the stop time of the vehicle Ve at time t2, and the capacity difference is a threshold value. If it is less than Cth, the internal ratio information is referred to determine the internal ratio corresponding to the current capacity difference, the determined internal ratio, the current open circuit voltage, the SOC-OCV curve for charging, The present charging rate may be estimated using the discharging SOC-OCV curve.

  That is, when the vehicle Ve is stopped traveling, the charging rate estimation unit 5 is when the capacity difference between the capacity of the battery B at the start of discharging and the capacity of the battery B at the end of discharging is less than the threshold Cth, and the vehicle When Ve is stopped, the current capacity difference is obtained by integrating at least one of the self-discharge current value and the dark current value by the stop time, and the current capacity is referred to by referring to the internal ratio information. The internal ratio corresponding to the difference is obtained, and the current charging rate is estimated using the obtained internal ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve. To do.

  FIG. 8C is a diagram showing still another example of the change in the charging rate of the battery B after the battery B is charged. In addition, the vertical axis | shaft of the graph shown in FIG.8 (c) shows the charging rate of the battery B, and the horizontal axis has shown time.

  First, the charging rate estimation unit 5 finishes charging the battery B with a battery or a charger mounted on the rescue vehicle (time t1), and calculates the capacity of the battery B before charging and the capacity of the battery B after charging. When the capacity difference is equal to or greater than the threshold value Cth, the charging rate SOC corresponding to the current open circuit voltage OCV is estimated as the current charging rate with reference to the charging SOC-OCV curve. Moreover, the charge rate estimation part 5 judges that the intersection of the open circuit voltage of the battery B and a charge rate exists on the SOC-OCV curve for charge at the time t1.

  After that, when the vehicle Ve is stopped, the battery B is discharged by the self-discharge current value and the dark current value. Therefore, the intersection of the open circuit voltage of the battery B and the charging rate is the charging SOC-OCV curve. It exists between the SOC-OCV curve for discharge or on the SOC-OCV curve for discharge.

  Then, when the vehicle Ve is stopped traveling, the charging rate estimation unit 5 passes the predetermined time T3 (time t2), and at least one of the self-discharge current value and the dark current value is determined by the stop time of the vehicle Ve. By integrating, the current capacity difference is obtained, and if the capacity difference is less than the threshold Cth, the internal ratio information corresponding to the current capacity difference is obtained by referring to the internal ratio information. The current charging rate is estimated using the ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve.

  That is, the charging rate estimation unit 5 is the case where the difference in capacity between the capacity of the battery B at the end of charging and the capacity of the battery B at the start of charging is equal to or greater than the threshold Cth at the end of charging of the battery B When Ve is stopped, the current capacity difference is obtained by integrating at least one of the self-discharge current value and the dark current value by the stop time, and the current capacity is referred to by referring to the internal ratio information. The internal ratio corresponding to the difference is obtained, and the current charging rate is estimated using the obtained internal ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve. To do.

  As described above, in the battery pack 1 according to the embodiment, the estimation is performed when the vehicle Ve stops traveling in consideration of the change in the charging rate due to the self-discharge current value and the dark current value of the battery B when the vehicle Ve stops traveling. Therefore, the charging rate of the battery B when the vehicle Ve is stopped traveling can be estimated with high accuracy. That is, according to the battery pack 1 of the embodiment, even when the vehicle Ve is stopped running, the battery B is charged even if the current flowing through the battery B is so small that the current detection unit 2 cannot detect it. The rate can be estimated with high accuracy.

The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention.
For example, the auxiliary machine provided in the battery pack 1 is not limited to the voltage detection unit 3 and the charging rate estimation unit 5, and may include other control units and peripheral devices in the battery pack 1, or voltage Only the detection unit 3 or only the charge rate estimation unit 5 may be used. Further, the auxiliary machine provided outside the battery pack is not limited to the travel control 6, the first load control unit 7 and the second load control unit 8, but may include other load control units, or the travel control. Only the unit 6 or only the first load control unit 7 may be used.

DESCRIPTION OF SYMBOLS 1 Battery pack 2 Current detection part 3 Voltage detection part 4 Memory | storage part 5 Charging rate estimation part 6 Travel control part 7 1st load control part 8 2nd load control part B Battery Re Relay Ve Vehicle

Claims (7)

SOC-OCV curve for charging indicating the correspondence between the charging rate of the battery obtained after charging the battery and the open circuit voltage of the battery, the correspondence between the charging rate obtained after discharging the battery and the open circuit voltage A discharge SOC-OCV curve, and an internal ratio when a line segment between the charge SOC-OCV curve and the discharge SOC-OCV curve is internally divided at a predetermined internal dividing point, A storage unit for storing internal ratio information indicating a correspondence relationship between the capacity of the battery at the start of discharge and the capacity difference between the capacity of the battery at the end of charge and discharge;
When the current difference in capacity is equal to or greater than a threshold value, the charging rate corresponding to the current open circuit voltage is determined by referring to the charging SOC-OCV curve or the discharging SOC-OCV curve. And when the current capacity difference is less than the threshold, the internal ratio information is referred to determine an internal ratio corresponding to the current capacity difference, and the obtained internal ratio and the current A charge rate estimator that estimates the current charge rate using the open circuit voltage, the charge SOC-OCV curve, and the discharge SOC-OCV curve;
With
When the vehicle equipped with the battery is stopped traveling, the charging rate estimation unit calculates at least one of a self-discharge current value of the battery and a dark current value flowing from the battery to the auxiliary device of the vehicle. A battery pack characterized in that the current capacity difference is obtained by integrating with a stop time. The battery pack according to claim 1,
The charging rate estimation unit receives a current value necessary for operation of the auxiliary device provided outside the battery pack when the vehicle is stopped from traveling from a travel control unit provided outside the battery pack. Then, the received current value is set as the dark current value. The battery pack according to claim 1,
The storage unit stores a reference value of a current flowing from the battery to the auxiliary device provided outside the battery pack,
The charging rate estimation unit receives a coefficient set for each auxiliary device through which current flows when the vehicle is stopped traveling from a travel control unit provided outside the battery pack, and the received coefficient and the A battery pack, wherein the result of multiplication with a reference value is the dark current value. The battery pack according to claim 1,
In the storage unit, the type of the auxiliary machine provided in the battery pack is associated with the current value flowing through the auxiliary machine provided in the battery pack when the vehicle is stopped traveling. Memorize correspondence information,
The charging rate estimation unit acquires a current value corresponding to the type of the auxiliary device through which a current flows when the vehicle is stopped traveling with reference to the correspondence information, and the acquired current value is the dark current. A battery pack characterized by its value. The battery pack according to claim 1,
In the storage unit, the type of the auxiliary machine provided outside the battery pack is associated with the current value flowing through the auxiliary machine provided outside the battery pack when the vehicle is stopped traveling. Memorize correspondence information,
The charging rate estimation unit receives a type of the auxiliary device through which a current flows when the vehicle is stopped traveling from a traveling control unit provided outside the battery pack, and corresponds to the received type of auxiliary device. A battery pack, wherein a current value is acquired with reference to the correspondence information, and the acquired current value is set as the dark current value. The battery pack according to claim 1,
A relay connected between the battery and the auxiliary device provided outside the battery pack;
The storage unit associates a type of the auxiliary machine provided in the battery pack with a current value flowing through the auxiliary machine provided in the battery pack when the vehicle is stopped traveling. 1 correspondence information, the type of the auxiliary device provided outside the battery pack, and the current value flowing through the auxiliary device provided outside the battery pack when the vehicle is stopped traveling. Storing the second correspondence information,
The charging rate estimation unit
When the relay is in an open state, a current value corresponding to the type of the auxiliary device through which a current flows when the vehicle is stopped is referred to the first correspondence information, and the acquired current value Is the dark current value,
When the relay is in a closed state, the type of the auxiliary device outside the battery pack through which current flows when the vehicle is stopped traveling is received from a travel control unit provided outside the battery pack, and the vehicle travels The current value corresponding to the type of auxiliary machine in the battery pack through which current flows when stopped is referred to the first correspondence information, and the current value corresponding to the received type of auxiliary machine is A battery pack obtained by referring to the second correspondence information, and using the total value of the obtained current values as the dark current value. The battery pack according to claim 1,
The charging rate estimation unit
When the capacity difference between the capacity of the battery at the start of discharge and the capacity of the battery at the end of discharge is greater than or equal to the threshold value, and the vehicle is stopped, the SOC-OCV curve for discharge To estimate a current charging rate corresponding to the open circuit voltage as the current charging rate,
When the capacity difference between the capacity of the battery at the start of discharge and the capacity of the battery at the end of discharge is less than the threshold, and when the vehicle is stopped running, or when the charging of the battery is completed When the capacity difference between the capacity of the battery at the end of charging and the capacity of the battery at the start of charging is greater than or equal to the threshold value, and the vehicle is stopped running, the self-discharge current value And at least one of the dark current values is integrated with the stop time to obtain the current capacity difference, and referring to the internal ratio information, the internal ratio corresponding to the current capacity difference is obtained. The present charging rate is estimated using the determined internal ratio, the current open circuit voltage, the charging SOC-OCV curve, and the discharging SOC-OCV curve. Battery pack.

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