JP5980458B1 - Power supply apparatus, transport apparatus having the power supply apparatus, estimation method for estimating correlation information between charging rate of storage unit and open-circuit voltage, and program for estimating correlation information - Google Patents

Abstract

To efficiently estimate more accurate correlation information between SOC and OCV of a power storage unit. A power supply device includes: a first power storage unit; a second power storage unit; a charge / discharge circuit that performs charge / discharge between the first power storage unit and the second power storage unit; and a control unit that controls the charge / discharge circuit; The control unit acquires at least one of the first power storage unit and the second power storage unit as a target power storage unit, obtains the charge rate of the target power storage unit, the target SOC and the target OCV that are open-circuit voltages, and the first power storage unit Using the charge transfer between the first power storage unit and the second power storage unit, the data including the target SOC and the target OCV is derived from an evaluation function based on the discrete state of the collected data, which is a set of data, with respect to the SOC and the target SOC. Collected and based on a plurality of data, the correlation information of the SOC and OCV of the target power storage unit is estimated. [Selection] Figure 8

Description

  The present invention relates to a power supply device, a transport device having the power supply device, an estimation method for estimating correlation information between a charging rate of an electricity storage unit and an open-circuit voltage, and a program for estimating the correlation information.

In a system including a plurality of storage batteries, a technology for grasping a relation of SOC (State Of Charge, charging rate) to OCV (Open Circuit Voltage) by performing charging / discharging between the storage batteries is known. .
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2008-220080

  There existed a subject that the more exact correlation information of SOC of an electrical storage part and OCV could not be estimated efficiently.

  A power supply apparatus according to a first aspect of the present invention controls a first power storage unit, a second power storage unit, a charge / discharge circuit responsible for charge / discharge between the first power storage unit and the second power storage unit, and the charge / discharge circuit. A control unit that acquires at least one of the first power storage unit and the second power storage unit as a target power storage unit, obtains a target SOC and target OCV that are a charging rate and an open-end voltage of the target power storage unit, Using charge transfer between the first power storage unit and the second power storage unit, data including the target SOC and the target OCV is derived from an evaluation function based on a discrete state with respect to the SOC of the collected data that is a set of data and the target SOC. The correlation information between the SOC and OCV of the target power storage unit is estimated based on a plurality of data.

  A transportation device according to a second aspect of the present invention includes the power supply device described above.

  The method according to the third aspect of the present invention includes a charge rate of a power supply device including a first power storage unit, a second power storage unit, and a charge / discharge circuit responsible for charge / discharge between the first power storage unit and the second power storage unit. And an open circuit voltage SOC and OCV correlation information, wherein at least one of the first power storage unit and the second power storage unit is a target power storage unit, and the SOC and OCV of the target power storage unit Using the step of obtaining a certain target SOC and target OCV, and charge transfer between the first power storage unit and the second power storage unit, the data including the target SOC and the target OCV is converted into the SOC of collected data that is a set of data. Collecting in the order derived from the evaluation function based on the discrete state and the target SOC, and estimating the SOC and OCV correlation information of the target power storage unit based on a plurality of data.

  A program according to a fourth aspect of the present invention is a charge rate of a power supply device including a first power storage unit, a second power storage unit, and a charge / discharge circuit responsible for charge / discharge between the first power storage unit and the second power storage unit. Is a program for estimating correlation information between SOC and OCV that are open-circuit voltages, and at least one of the first power storage unit and the second power storage unit is a target power storage unit, and the SOC and OCV of the target power storage unit The target SOC and the target OCV are obtained, and the charge transfer between the first power storage unit and the second power storage unit is used to convert the data including the target SOC and the target OCV into the collected data that is a set of data. The steps of collecting in an order derived from the discrete state for the SOC and the evaluation function based on the target SOC, and estimating the correlation information between the SOC and the OCV of the target power storage unit based on a plurality of data are implemented in the computer. Make.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is a block diagram of the transportation equipment concerning this embodiment. It is a figure for comparing the electric power output by the case where a single storage battery is used, and the electric power output by the case where two storage batteries are used. It is a figure explaining the SOC-OCV curve of a storage battery. It is a figure explaining the procedure until it determines a SOC-OCV curve. It is a figure explaining the calculation for determining a coordinate on plane space. It is an internal block diagram of battery ECU. It is a figure for demonstrating the relationship between the (SOC, OCV) data and the accuracy of an SOC-OCV curve. An example of calculating the discreteness of the SOC will be shown. Is a diagram illustrating the information for calculating the time T _M required for charge transfer. An example of the discreteness calculated for every SOC, operation time, and an evaluation value is shown. It is a flowchart until it determines a SOC-OCV curve. It is a flowchart until it determines SOC which becomes the next acquisition object.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a block diagram of a transportation device 10 according to the present embodiment. The transportation device according to the present embodiment is an electric vehicle, for example. In the following description, it is assumed that the power storage device 100 according to the present embodiment is mounted and used in an electric vehicle. The power storage device 100 is an example of a power supply device.

  The transport device 10 travels when the PDU 141 which is a power drive unit receives the driving power supplied from the mounted power storage device 100 and the PDU 141 rotates the motor generator MG.

  PDU 141 is connected to power storage device 100 via main positive bus MPL and main negative bus MNL. The smoothing capacitor C is connected between the main positive bus MPL and the main negative bus MNL, and reduces the high frequency component of the conducting power. The third voltage sensor 142 detects a voltage Vh between the main positive bus MPL and the main negative bus MNL, and the detected voltage Vh is used for controlling the PDU 141.

  PDU 141 converts drive power (DC power) supplied from main positive bus MPL and main negative bus MNL into AC power and outputs the AC power to motor generator MG. Motor generator MG includes, for example, a three-phase AC rotating electric machine. Motor generator MG rotates the wheels via the power transmission mechanism and the drive shaft. In addition, PDU 141 converts AC power generated by motor generator MG during wheel deceleration to DC power, and outputs it as regenerative power to main positive bus MPL and main negative bus MNL.

  First storage battery 111 and second storage battery 121 included in power storage device 100 are charged with regenerative power generated by the motor generator and external power from external power supply 153.

  Charging converter 151 is provided between main positive bus MPL and main negative bus MNL and power receiving unit 152. Charging converter 151 converts AC power supplied from external power supply 153 (for example, a household AC power supply) via power receiving unit 152 into DC power, and outputs the DC power to main positive bus MPL and main negative bus MNL. The power receiving unit 152 is an input terminal for inputting AC power supplied from the external power source 153. Charging converter 151 may be connected to positive line PL1 and negative line NL1 instead of or in addition to main positive line MPL and main negative line MNL, and is connected to positive line PL2 and negative line NL2. May be.

  The power storage device 100 includes a first power storage module 101, a second power storage module 102, and a charge / discharge circuit module 103. The first power storage module 101 includes a first storage battery 111, a first voltage sensor 112, a first current sensor 113, and a first switch 114. The second power storage module 102 has the same configuration as the first power storage module 101, and includes a second storage battery 121, a second voltage sensor 122, a second current sensor 123, and a second switch 124. The charge / discharge circuit module 103 is responsible for charge / discharge between the first storage battery 111 and the second storage battery 121. The charge / discharge circuit module 103 includes a battery ECU 130 as a control unit, and a first VCU 131, a second VCU 132, and a third switch 133 that can function as a charge / discharge circuit.

  In the present embodiment, the first storage battery 111 functioning as the first power storage unit and the second storage battery 121 functioning as the second power storage unit are chargeable / dischargeable DC power sources, for example, lithium ion batteries, nickel hydrogen batteries, sodium Includes secondary batteries such as ion batteries and lithium-sulfur batteries. In addition, a chargeable / dischargeable element such as a capacitor or a capacitor may be used. However, the first storage battery 111 and the second storage battery 121 are batteries having different characteristics. Specifically, the first storage battery 111 is a so-called high output battery having a mass output density that is output power per unit mass larger than that of the second storage battery 121. On the other hand, the second storage battery 121 is a so-called high capacity battery in which the mass energy density, which is the stored power per unit mass, is larger than that of the first storage battery 111. The first storage battery 111 may have a larger volume output density that is output power per unit volume than the second storage battery 121, and the second storage battery 121 may have a larger volume energy density that is stored power per unit volume than the first storage battery 111. good. Thus, the power that can be extracted from the first storage battery 111 per unit mass or unit volume is greater than the power that can be extracted from the second storage battery 121 per unit mass or unit volume. On the other hand, the power stored in the first storage battery 111 per unit mass or unit volume is smaller than the power stored in the second storage battery 121 per unit mass or unit volume. Thus, the 1st storage battery 111 is inferior to an energy density compared with the 2nd storage battery 121, and is excellent in an output density.

First storage battery 111 is connected to first VCU 131 via positive line PL1 and negative line NL1. First voltage sensor 112 detects a voltage between positive line PL1 and negative line NL1, that is, voltage V1 of _first storage battery 111, and outputs the detected value to battery ECU 130. First current sensor 113 detects current I ₁ input / output to / from first storage battery 111 and outputs the detected value to battery ECU 130.

The first switch 114 is a switch for opening and closing the circuit of the positive electrode line PL1 and negative electrode line NL1, receives a switching instruction signal CW ₁ from the battery ECU 130, switches the open and closed states. V ₁ detected by the first voltage sensor 112 when the first switch 114 is in the open state is OCV ₁ that is the OCV in the first storage battery 111.

Second storage battery 121 is connected to second VCU 132 via positive electrode line PL2 and negative electrode line NL2. Second voltage sensor 122 detects the voltage _{V 2} of the voltage or the second battery 121 between the positive electrode line PL2 and negative electrode line NL2, and outputs the detected value to battery ECU 130. Second current sensor 123 detects current I ₂ input / output to / from second storage battery 121 and outputs the detected value to battery ECU 130.

The second switch 124 is a switch for opening and closing the circuit of the positive electrode line PL2 and negative electrode line NL2, receives a switching instruction signal CW ₂ from the battery ECU 130, switches the open and closed states. V ₂ detected by the second voltage sensor 122 when the second switch 124 is in the open state is OCV ₂ that is the OCV in the second storage battery 121.

  The first current sensor 113 and the second current sensor 123 detect the current (discharge current) output from the corresponding storage battery as a positive value and the input current (charge current and regenerative current) as a negative value. To detect. Although FIG. 1 shows a configuration in which the current of the positive electrode line is detected, it may be configured to detect the current of the negative electrode line.

The 1VCU131 includes a positive line PL1 and negative line NL1, provided between the connection positive line BPL and connected negative polar BNL, receives a control signal CV ₁ from the battery ECU 130, a positive line PL1 and negative line NL1, Voltage conversion is performed between the connection positive line BPL and the connection negative line BNL. The 2VCU132 includes a positive line PL2 and negative electrode line NL2, provided between the connection positive line BPL and connected negative polar BNL, receives a control signal CV ₂ from the battery ECU 130, a positive electrode line PL2 and negative electrode line NL2, Voltage conversion is performed between the connection positive line BPL and the connection negative line BNL.

Connection positive line BPL is connected to main positive bus MPL, and connection negative line BNL is connected to main negative bus MNL. A third switch 133 is provided at the connection portion. The third switch 133 is a switch for opening and closing the connection positive line BPL and main positive bus MPL, and connecting a negative polar BNL and main negative bus MNL in path, receiving the switching instruction signal CW ₃ from the battery ECU 130, the open state And switch between closed states.

  In the above configuration, when the first switch 114 and the third switch 133 are closed and the second switch 124 is opened, the power of the first storage battery 111 is supplied to the PDU 141. When the second switch 124 and the third switch 133 are closed and the first switch 114 is opened, the power of the second storage battery 121 is supplied to the PDU 141. Further, when the first switch 114, the second switch 124, and the third switch 133 are closed, both the power of the first storage battery 111 and the power of the second storage battery 121 are supplied to the PDU 141. However, when both the power of the first storage battery 111 and the power of the second storage battery 121 are supplied to the PDU 141, voltage conversion is performed by the first VCU 131 and the second VCU 132 so that the supply voltages are the same. When regenerative power is supplied from the PDU 141 or when external power is supplied from the external power source 153, the power flow is reversed in each of the above cases.

  Further, in this embodiment, a so-called 2VCU method is employed in which each storage battery is provided with a VCU that is a voltage conversion unit. From the viewpoint of adjusting the output voltage of the other storage battery with respect to the output voltage of one storage battery, A so-called 1VCU system in which one VCU is provided in any of them may be adopted. If it is 1VCU system, it will contribute to the reduction of the space which installs VCU. It also contributes to cost reduction and weight reduction. In this case, the voltage supplied to the PDU 141 is the output voltage of the storage battery in which no VCU is provided. If this restriction is inconvenient, the 2VCU method may be adopted.

  The converters are roughly classified into a step-up type, a step-down type, and a step-up / step-down type, but the first VCU 131 and the second VCU 132 can employ any type of converter. Further, the type of converter employed in the first VCU 131 and the second VCU 132 may be different. By appropriately combining the first storage battery 111 and the second storage battery 121 and the type of the converter, it can be used as a single battery as a whole that satisfies the required specifications.

When the first switch 114 and the second switch 124 are closed and the third switch 133 is opened, charging / discharging is performed between the first storage battery 111 and the second storage battery 121. The charge / discharge between the storage battery units is performed according to the difference between the converted voltage value of the first VCU 131 determined by the control signal CV ₁ from the battery ECU 130 and the converted voltage value of the second VCU 132 determined by the control signal CV ₂ . The flow of is determined. Therefore, battery ECU 130 transmits control signals CV ₁ and CV ₂ instructing the converted voltage value to each VCU, thereby determining which storage battery is the power supply side and which storage battery is the power reception side. Can be controlled. In addition, the voltage conversion is stopped by fixing one high side switch of the first VCU 131 and the second VCU 132 to “closed” and the low side switch to “open”, and the output voltage of the storage battery is output as it is. The other conversion voltage value may be controlled to change. At this time, the battery ECU 130 can grasp the charge / discharge amount in the first storage battery 111 by monitoring V ₁ and I _1, and the charge / discharge amount in the second storage battery 121 by monitoring V ₂ and I _2. Can be grasped.

  As described above, the power storage device 100 according to this embodiment includes two storage batteries having different characteristics. In a system using a plurality of storage batteries having different characteristics, it is necessary to finely control how to respond to the required power supply in accordance with the characteristics and state of each storage battery. First, the difference between the power output when a single storage battery is used and the power output when a plurality of storage batteries having different characteristics is used will be described.

  FIG. 2 is a diagram for comparing the power output when a single storage battery is used with the power output when two storage batteries having different characteristics are used. The horizontal axis represents the passage of time, and the vertical axis represents the power output. A region where the power output is negative indicates that power is accepted by regenerative power, for example.

  SB indicated by a solid line represents a change in output power when the power storage device is configured by one storage battery. When the power storage device includes only one storage battery, the power required from the load side is output as required within the capacity range, and the input power is accepted as it is. Therefore, there is a case where large input / output is performed in a short time, and there is a problem that the storage battery is rapidly deteriorated.

  When the power storage device is constituted by two storage batteries having different characteristics, the input / output can be shared according to the respective characteristics. OB represented by a dotted line represents a change in the output power of the high-power battery, and VB represented by a double line represents a change in the output power of the high-capacity battery. At each time, when the value of OB and the value of VB are added together, the value becomes SB. That is, it shows a state where power required from the load side is shared between the high capacity battery and the high capacity battery.

  In general, a high-capacity battery deteriorates with respect to a high input / output and instantaneous fluctuations of the input / output. Therefore, the battery is controlled so that the input / output is performed within a range in which the progress of deterioration is suppressed. preferable. Therefore, as can be seen from the changes in OB and VB, when a large input / output is required from the load side, in principle, a high-power battery (OB) takes charge, and even if a high-power battery cannot respond, Control assisted by the capacity type battery (VB) is performed. Further, the high capacity battery is suitable for continuous output at a value that is not so high. In this case, the output of the high output battery can be suppressed. In addition, since the high-capacity battery has a characteristic that it easily deteriorates when regenerative power corresponding to charging at a high rate is accepted, control is performed so that the regenerative power is received by the high-power battery as much as possible. In addition, when regenerative electric power exceeds the capacity | capacitance accepted with a high output type battery, you may operate | release a brake and reduce generation | occurrence | production of regenerative electric power besides accepting with a high capacity | capacitance type battery. In this case, deterioration of the high capacity battery can be suppressed.

  In addition, the high-capacity battery and the high-power battery have greatly different deterioration influence levels based on the SOC. In the high capacity battery, even if the SOC changes, the deterioration influence level does not change greatly. In other words, any value of SOC does not greatly affect the progress of deterioration. On the other hand, when the SOC of the high-power battery changes, the degree of deterioration influences greatly according to the value. More specifically, in the central region where the SOC is 30 to 70%, the deterioration influence degree of the high-power battery is small, but the deterioration influence degree increases as the distance from the central region increases. That is, the deterioration progresses as the distance from the central area increases. Therefore, it is preferable to adjust the charge / discharge amounts of the high-capacity battery and the high-power battery so that the SOC of the high-capacity battery does not belong to the low range of 0 to 30% or the high range of 70 to 100%. .

  By using a plurality of storage batteries having different characteristics as described above, it is possible to meet various output requests from the load side while suppressing deterioration of each storage battery. However, how to properly use each storage battery and what ratio to mix the input and output is important to accurately grasp the current state of the storage battery, and change or modify it appropriately according to the state. is there. In particular, accurate grasp of the SOC that changes every moment is very important for drive control of transportation equipment.

  Therefore, the correlation between SOC and OCV in the storage battery will be described. FIG. 3 is a graph showing an SOC-OCV curve of a certain battery. The SOC-OCV curve is an example of correlation information that is the relationship between SOC and OCV. The horizontal axis represents SOC in percent (%), and the vertical axis represents OCV in volts (V).

  The plurality of curves drawn on the graph represent SOC-OCV curves for different capacity maintenance rates. The capacity maintenance rate indicates the degree of deterioration due to repeated use and deterioration over time. Specifically, the amount of electricity that can be stored when new (100%), how much is fully charged This is the percentage of electricity that can be stored. For example, a storage battery that can store only 80% of the initial stored electricity when the battery is fully charged at a certain point of repeated use is a storage battery with a capacity maintenance rate of 80%. In other words, it can be said that the capacity maintenance rate indicates the degree of deterioration of the storage battery.

  In FIG. 3, the solid line represents the SOC-OCV curve with a capacity retention rate of 100%, the dotted line is 90%, the alternate long and short dash line is 80%, the alternate long and two short dashes line is 70%, and the broken line is the 60% SOC-OCV curve. Note that the SOC when the capacity maintenance rate is not 100% is the charging rate when the stored electricity amount of full charge in a state where deterioration has progressed is 100%. As the deterioration progresses, it can be seen that the curve transitions in the upper left direction as a whole. For example, when the OCV is 3.90 V, it can be read that the SOC when the capacity maintenance ratio is 90% is 70%, whereas the SOC when the capacity maintenance ratio is 70% is 60%. Many accumulators generally exhibit this trending nature.

  That is, the SOC estimated from the same OCV varies greatly depending on how much the storage battery mounted in the power storage device is currently deteriorated. That is, even if the OCV is measured, the SOC cannot be accurately grasped without considering the deterioration state of the storage battery.

  Therefore, the power storage device 100 according to the present embodiment charges and discharges for determining the SOC-OCV curve for each of the first storage battery 111 and the second storage battery 121 to be mounted at each time point that satisfies a predetermined condition. Execute control.

  FIG. 4 is a diagram for explaining a procedure until the SOC-OCV curve is determined at a certain time point. As in FIG. 3, the horizontal axis represents SOC in percent (%), and the vertical axis represents OCV in volts (V). Each of the plurality of curves shown represents an SOC-OCV curve for each capacity retention rate of the modeled storage battery according to the line type used in FIG.

As a result of repeated studies on various storage batteries, the applicant has found that many storage batteries have a range in which the variation of SOC with respect to a certain OCV falls within a certain range even if the SOC-OCV curves have different capacity maintenance rates. Found to exist. Such a region is referred to as a “reference region”. The reference region can be found, for example, in a range where the SOC is close to 100%. This is because the SOC at the full charge voltage of the storage battery is defined as 100%. Therefore, if the storage battery voltage is in the vicinity of the full charge voltage, the SOC will be in the vicinity of 100% regardless of the capacity maintenance rate. . In the example of FIG. 4, the extent OCV of _{V R (O min ≦ V 0} <O max), be any capacity retention rate, the remaining capacity is _{S R (S min ≦ S 0} <S max) of Indicates that it is within the range. The OCV of the range of V _R is referred to as a "reference OCV", the SOC of the range of _{S R} will be referred to as a "reference SOC".

The range of the reference region is preferably 0.1 V (the difference between O _max and O _min ) as the range of the reference OCV, and 3% (the difference between S _max and S _min ) as the range of the reference SOC. The range of the reference OCV here may be a voltage range in a single cell. The range of the reference OCV may be 3% of the nominal voltage of the storage battery. The range of the reference region may be optimized as appropriate according to the characteristics of the target storage battery, the required accuracy, and the like.

As described above, the power storage device 100 according to the present embodiment can charge and discharge between the storage battery units between the first storage battery 111 and the second storage battery 121. That is, the power of one storage battery can be transferred to the other. Then, by performing charging / discharging between the storage battery parts, the OCV of the storage battery on the side where the SOC-OCV curve is to be determined can be moved to the range of the reference OCV in the storage battery. Since the SOC corresponding to the reference OCV is the reference SOC regardless of the capacity maintenance ratio, if the value is an average value of, for example, _Smin and _Smax , the SOC-OCV two-dimensional plane (here, “SO plane”). The coordinates Sp ₀ (St ₀ , Ot ₀ ) can be plotted in the reference area above.

Then, charging / discharging between storage battery parts is repeated according to a predetermined condition and the number of times. At this time, for example, when the storage battery on the side on which the SOC-OCV curve is to be determined is the first storage battery 111, the increase / decrease in the SOC of the first storage battery 111 is monitored by monitoring the current I ₁ of the first current sensor 113. Can be calculated. Moreover, if the 1st switch 114 is made into an open state, OCV of the 1st storage battery 111 at that time can also be detected. Then, each time charging / discharging between storage battery parts is performed, one coordinate Sp can be plotted on the SO plane. In the example of FIG. 4, after obtaining the coordinate Sp ₀ in the reference region, the charging / discharging between the storage battery units is repeated three times to obtain the coordinates Sp ₁ , Sp ₂ , Sp ₃ .

  For example, an SOC-OCV curve for each capacity maintenance rate is prepared in advance as reference data for each model number of a storage battery by a battery manufacturer. In FIG. 4, SOC-OCV curves at 100%, 90%, 80%, 70%, and 60% are reference data. The reference data is preferably prepared at a finer ratio such as 5% or 1%. Alternatively, in the range where the SOC-OCV curve variation with respect to the capacity maintenance rate is large, the reference data may be provided at a smaller ratio than in the small range, and the amount of data and the effort required for preparing the reference data can be reduced. Although specifically described later, the power storage device 100 stores this reference data in the storage unit, and the battery ECU 130 can refer to it appropriately.

  When the plurality of coordinates Sp are obtained by repeating charging and discharging between the storage battery units, the battery ECU 130 selects the SOC-OCV curve having the highest degree of coincidence with respect to these coordinates from the reference data by matching processing. For example, an SOC-OCV curve having the smallest deviation from a plurality of coordinates Sp is selected. The SOC-OCV curve selected at this time is the most probable SOC-OCV curve at that time. In this way, the SOC-OCV curve of the storage battery at that time is estimated. In the example of FIG. 4, it is an SOC-OCV curve with a capacity maintenance rate of 90%. By storing this SOC-OCV curve, if the OCV is measured in response to the confirmation of the SOC required from the outside, the highly accurate SOC at that time can be returned immediately. The SOC-OCV curve that is appropriately determined by performing charging / discharging between the storage battery parts in this way is a more faithful representation of the actual SOC-OCV curve at that time, and is very close to the actual SOC. The SOC can be returned in response to a confirmation request from the outside.

In the above description, first, although the coordinates Sp ₀ in the reference region is subjected to the storage battery unit mesenchyme discharge so as to obtain the order to obtain the coordinates Sp is not limited thereto. If at least one coordinate Sp is included in the reference region as a result of performing charge / discharge between the storage battery parts a plurality of times, the reference data and matching processing can be performed. When excessive charging / discharging between power storage units is required to set the SOC and OCV of one storage battery as the reference region, an SOC-OCV curve is generated while obtaining a plurality of coordinates by multiple charging / discharging between power storage units. It is preferable to move the voltage and SOC of the storage battery to the reference region. And by correcting the coordinates obtained by charging / discharging between power storage units a plurality of times based on the reference region, the voltage and SOC of the power storage unit that generates the SOC-OCV curve in the reference region belong only to the reference region. An accurate SOC-OCV curve that does not require excessive charging / discharging between power storage units can be generated.

  In the above description, the SOC-OCV curve having the highest degree of coincidence is selected from the reference data. However, first, a plurality of SOC-OCV curves whose respective coordinate deviations are equal to or less than the threshold are selected, and other criteria are selected from the selected SOC-OCV curves. One SOC-OCV curve may be determined based on the above. Another criterion is that the newly acquired coordinates have a smaller deviation. With such a configuration, it is possible to specify the SOC-OCV curve even in a state where charging / discharging between power storage units must be stopped halfway due to some circumstances.

Here, a procedure for charging / discharging between the storage battery parts to determine the next coordinate Sp will be described. FIG. 5 is a diagram for explaining calculation for determining coordinates in a plane space. Sp _n represented by the first x mark is plotted on the SO plane as the _n-th coordinate, and is represented by coordinate values (St _n , Ot _n ). After that, the n + 1-th coordinate plotted by performing one charge / discharge between the storage battery parts is Sp _{n + 1} represented by the second x mark.

The difference between the coordinate values is represented by OCV as ΔOCV and SOC as ΔSOC, which may be positive values or negative values. That is,
(St _{n + 1} , Ot _{n + 1} ) = (St _n + ΔSOC, Ot _n + ΔOCV)
It is. Here, since both Ot _n and Ot _{n + 1} are OCV, these values are obtained directly by actual measurement. On the other hand, ΔSOC is ΔSOC = St _{n + 1} −St _n ,
ΔSOC = ΣI / C _full
Or
ΔSOC = ΔAh / C _full
Is calculated by Here, ΣI is the sum of the values output by the current sensor from time t _n to time t _{n + 1} , and ΔAh represents the amount of electricity that has changed during this time. C _full is the amount of electricity at the time of full charge when the previous SOC-OCV curve is determined. The value of C _full is stored in the storage unit every time the SOC-OCV curve is determined. For example, when the SOC-OCV curve is determined, C _full is determined from the capacity maintenance rate and the initial capacity corresponding to the determined SOC-OCV curve.

  In the above description, the description has been given mainly using the coordinates SP on the two-dimensional plane for the purpose of easily explaining the SOC-OCV curve determination process. Plotting the coordinate SP or specifying the coordinate SP corresponds to acquiring and storing (SOC, OCV) data as internal processing. In the above description, the case where one OCV is acquired for each SOC has been mainly described for the purpose of easily explaining the SOC-OCV curve determination process. However, one or more OCVs may be acquired for each SOC.

  How the battery ECU 130 performs the determination of the SOC-OCV curve described above will be described with the battery ECU 130 represented by functional blocks. FIG. 6 shows an internal block diagram of battery ECU 130 together with a recording medium 290 that stores a program for battery ECU 130.

  As shown in the figure, the battery ECU 130 includes a control calculation unit 230 that performs overall control and calculation, a ΔSOC calculation unit 231, a time measurement unit 232, a BATT information storage unit 233, and a confirmed line holding unit 234. Processing is performed until the SOC-OCV curve is determined by these functional blocks. In addition to this, battery ECU 130 mainly includes an SOC response unit 235.

  The control calculation unit 230 sets at least one of the first storage battery 111 and the second storage battery 121 as the target storage battery. The target storage battery is, for example, a storage battery that is an estimation target of the SOC-OCV curve. The control calculation unit 230 may select at least one of the first storage battery 111 and the second storage battery 121 as a target storage battery according to a predetermined selection condition. When the first storage battery 111 and the second storage battery 121 are selected as the storage batteries to be estimated for the SOC-OCV curve, the control calculation unit 230 may select the first storage battery 111 with higher output density as the target storage battery. . The control calculation unit 230 acquires the target SOC and the target OCV, which are the charging rate and voltage of the target storage battery, and uses the charge transfer between the first storage battery 111 and the second storage battery 121, and includes the target SOC and the target OCV. Are collected in the order derived from the evaluation function based on the discrete state of the collected data that is a set of data and the SOC and the target SOC, and based on the plurality of data, the correlation information between the SOC and the OCV of the target power storage unit is estimated To do. Note that data including the target SOC and the target OCV may be referred to as (SOC, OCV) data.

  The control calculation unit 230 derives uncollected data that is a set of data not collected based on the collected data. The evaluation function may be a function based on a discrete state when an uncollected SOC that is an SOC included in uncollected data is collected. The evaluation function may be a function based on the amount of change in the discrete state when uncollected SOC is collected. The evaluation function may be a function that evaluates higher as data including uncollected SOC that increases the discrete state when collected. The evaluation function may be a function further based on the operation time including the time required for the charge transfer calculated from the difference between the uncollected SOC and the target SOC. The operation time may include a time required for the time change of the voltage of the target power storage unit to stabilize after the charge transfer. The evaluation function may be a function that evaluates higher as data including uncollected SOC with shorter operation time. The evaluation function may be a function that strongly evaluates the change amount of the discrete state from the operation time.

  In addition, the control arithmetic unit 230 applies the target storage battery to the target storage battery when the SOC of the target storage battery is included in the range of the reference SOC that is the SOC in which the difference in OCV with respect to the same SOC is equal to or less than the threshold value in a plurality of deterioration states of the target storage battery The target SOC may be acquired based on the charge transfer amount. Further, the control calculation unit 230 may acquire the target SOC based on the amount of charge transfer to the target storage battery from when the SOC of the target storage battery is included in the range of the reference OCV that is the OCV corresponding to the reference SOC. The control calculation unit 230 may collect (SOC, OCV) data so that the reference SOC and the reference OCV are included as the target SOC and the target OCV.

  When the SOC of the target storage battery before the charge transfer is not included in the range of the reference SOC, the control calculation unit 230 is configured so that the SOC of the target storage battery is included in the range of the reference SOC before the charge transfer. Charging / discharging between 111 and the second storage battery 121 may be performed. When the OCV of the target storage battery before charge transfer is not included in the range of the reference OCV, the control calculation unit 230 includes the first storage battery 111 and the second storage battery so that the OCV of the target storage battery is included in the range of the reference OCV. Charging / discharging to / from 121 may be performed.

  At least one of first storage battery 111 and second storage battery 121 supplies electric power to motor generator MG. Motor generator MG is an example of a drive unit. The charge / discharge circuit module 103 may be responsible for charge / discharge between the first storage battery 111, the second storage battery 121, and the motor generator MG. The control calculation unit 230 may control the charge / discharge circuit module 103 so that the first storage battery 111 and the second storage battery 121 do not perform charge / discharge with the drive unit while performing the charge transfer. Note that the control calculation unit 230 may preferentially select the first storage battery 111 that has lower energy density and higher output density than the second storage battery 121 as the target storage unit.

  Battery ECU 130 is a kind of computer. The control arithmetic unit 230 is configured by, for example, an MPU, executes a program stored in, for example, an internal storage unit of the MPU, and controls the entire power storage device 100 according to the program. A program executed by the battery ECU 130 is supplied from the recording medium 290 to the battery ECU 130. The recording medium 290 is an example of a medium that can be read by a computer. Any medium in which a program or computer instruction is stored in battery ECU 130 can be regarded as a medium for storing a program for battery ECU 130.

The control calculation unit 230 controls the charge / discharge circuit module 103. In addition, the control calculation unit 230 transmits opening / closing instruction signals CW ₁ , CW ₂ , and CW ₃ to open and close the first switch 114, the second switch 124, and the third switch 133 according to the situation. In addition, control signals CV ₁ and CV ₂ that are PWM signals are transmitted to the respective _first VCU 131 and second VCU 132 in order to adjust the converted voltages. The ΔSOC calculation unit 231 acquires I ₁ from the first current sensor 113 and calculates ΔSOC when acquiring (SOC, OCV) data of the first storage battery 111. Similarly, when (SOC, OCV) data of the second storage battery 121 is acquired, I ₂ is acquired from the second current sensor 123 to calculate ΔSOC. The ΔSOC calculation unit 231 delivers the calculated ΔSOC to the control calculation unit 230.

  The timekeeping unit 232 delivers the time when charging / discharging between the storage battery units is performed to the control calculation unit 230. The control calculation unit 230 stores the time when the (SOC, OCV) data is acquired in the internal storage unit, and a predetermined elapsed time has passed from the time when the (SOC, OCV) data is acquired. In addition, it is excluded from the target of the matching process.

  The BATT information storage unit 233 is a storage unit that stores the reference data. Specifically, it is configured by a non-volatile flash memory or the like. The BATT information storage unit 233 acquires reference data from an external device. The BATT information storage unit 233 stores not only the reference data but also various information related to the storage battery, and provides it to the control calculation unit 230 as necessary. The BATT information storage unit 233 stores the correlation information between the SOC and the OCV in the plurality of deterioration states of the first storage battery 111 in advance. The BATT information storage unit 233 stores the correlation information between the SOC and the OCV in the plurality of deterioration states of the second storage battery 121 in advance. For example, when the power storage device 100 is manufactured, the correlation information between the SOC and the OCV in the plurality of deterioration states of the first storage battery 111 and the correlation information between the SOC and the OCV in the plurality of deterioration states of the second storage battery 121 are stored in the BATT information storage unit. 233. Of the first storage battery 111 and the second storage battery 121, the correlation information may not be stored in the BATT information storage unit 233 for storage batteries that are not subject to estimation of the SOC-OCV curve. The control calculation unit 230 conforms to a plurality of (SOC, OCV) data including the target SOC and the target OCV among the correlation information of the SOC and the OCV in the plurality of deterioration states of the target storage battery stored in the BATT information storage unit 233. The correlation information having a higher degree may be selected with higher priority as the correlation information to be estimated. The control calculation unit 230 may estimate the correlation information based on an approximate curve or an approximate line for a plurality of data including the target SOC and the target OCV.

  The confirmed line holding unit 234 is a storage unit that stores the SOC-OCV curve confirmed by the control calculation unit 230. Specifically, it is configured by a non-volatile flash memory or the like. The storage unit may be configured integrally with the BATT information storage unit 233.

The SOC response unit 235 is connected to the confirmed line holding unit 234. When the SOC response unit 235 receives an SOC inquiry from the outside, the SOC response unit 235 acquires V ₁ and V ₂ as the OCV, refers to the SOC-OCV curve stored in the confirmed line holding unit 234, and returns the SOC. When the correlation information of the first storage battery 111 is estimated by the control calculation unit 230, the SOC response unit 235 receives the OCV of the first storage battery 111 and the control calculation unit 230 when receiving an inquiry about the SOC of the first storage battery 111. The SOC of the first storage battery 111 is calculated and responded based on the correlation information estimated by. When the correlation information of the second storage battery 121 is estimated by the control calculation unit 230, the SOC response unit 235 receives the OCV of the second storage battery 121 and the control calculation unit 230 when receiving an inquiry about the SOC of the second storage battery 121. Based on the correlation information estimated by the above, the SOC of the second storage battery 121 is calculated and responded.

  FIG. 7 is a diagram for explaining the relationship between (SOC, OCV) data and the accuracy of the SOC-OCV curve. In FIG. 7, an SOC-OCV curve 780 shows an SOC-OCV curve when the capacity maintenance rate is 80%. The SOC-OCV curve 770 shows the SOC-OCV curve when the capacity maintenance rate is 70%. As shown in the figure, it is assumed that (SOC, OCV) data has already been acquired for each of SOCs of 50%, 60%, 90%, and 100%. The current SOC is assumed to be 60%.

  Assume that it is predetermined to acquire (SOC, OCV) data at 10% increments in the range from 10% to 100% in order to select the SOC-OCV definite line. Specifically, the SOCs from which (SOC, OCV) data is acquired are 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%. .

  As shown in the drawing, the four (SOC, OCV) data already acquired are in the vicinity of the SOC-OCV curve 780 and the SOC-OCV curve 770. For this reason, it is not possible to select a confirmed line with high accuracy from the currently collected (SOC, OCV) data.

  In this case, assume that the SOC is 80% (SOC, OCV) and data is acquired. It is assumed that the capacity maintenance rate is 70% and (SOC, OCV) data indicated by reference numeral 703 is acquired. The point indicated by reference numeral 703 is also located in the vicinity of the SOC-OCV curve 780. Therefore, the current SOC-OCV curve cannot be selected with high accuracy from the collected five (SOC, OCV) data.

  On the other hand, assuming that the capacity maintenance rate is 80%, it is assumed that (SOC, OCV) data indicated by reference numeral 704 is acquired. Even in this case, the point indicated by reference numeral 703 is also located in the vicinity of the SOC-OCV curve 770. Therefore, even in this case, the current SOC-OCV curve cannot be selected with high accuracy from the collected five (SOC, OCV) data. That is, even if (SOC, OCV) data is acquired when the SOC is 80%, there is a high possibility that the current SOC-OCV curve cannot be selected with high accuracy.

  On the other hand, the case where (SOC, OCV) data is acquired with the SOC set to 40% will be described. Assume that the capacity maintenance rate is 70%, and (SOC, OCV) data indicated by reference numeral 701 is acquired. A point indicated by reference numeral 701 is located in the vicinity of the SOC-OCV curve 770 and is separated from the SOC-OCV curve 780. Therefore, the SOC-OCV curve 770 can be selected with high accuracy from the collected five (SOC, OCV) data as the current SOC-OCV curve.

  Further, it is assumed that the capacity maintenance rate is 80% and (SOC, OCV) data indicated by reference numeral 702 is acquired. A point indicated by reference numeral 702 is located in the vicinity of the SOC-OCV curve 780 and is separated from the SOC-OCV curve 770. Therefore, even in this case, the SOC-OCV curve 780 can be selected with high accuracy as the current SOC-OCV curve from the collected five (SOC, OCV) data. That is, by acquiring (SOC, OCV) data when the SOC is 40%, the current SOC-OCV curve is higher than when acquiring (SOC, OCV) data when the SOC is 80%. The possibility of selecting with accuracy increases.

  Therefore, by acquiring the SOC at 40% (SOC, OCV) data, the possibility of acquiring data useful for determining the SOC-OCV curve increases. Therefore, there is a case where the SOC-OCV curve can be determined with sufficient accuracy without acquiring (SOC, OCV) data with all SOCs from 10% to 100%. As described above, by setting the acquisition target SOC, which is the SOC that is the acquisition target of the next data, to 40%, the SOC-OCV curve may be determined more efficiently than when the acquisition target SOC is set to 80%. .

  As a result of repeated studies by the inventors, the (SOC, OCV) data acquired in many power storage units is made more discrete with respect to the SOC, so that a more accurate SOC-OCV curve can be efficiently obtained. It can be expected to be able to be determined. Therefore, the control calculation unit 230 determines the SOC from which (SOC, OCV) data is to be acquired next, based on the discreteness of the SOC.

  FIG. 8 shows an example of calculating the discreteness of the SOC. The control calculation unit 230 calculates the discrete degree by dividing the SOC range of the collected data by the number of SOCs from which the data has been acquired. The control calculation unit 230 calculates the SOC range of the collected data by (maximum SOC value in the collected data−minimum SOC value of the collected data + 10%). In addition, the discrete degree calculated by this indicates that the smaller the value, the larger the discrete degree of the data.

  For example, in the state shown in FIG. 8, when (SOC, OCV) data at an SOC of 80% is acquired, the discrete degree is calculated as 8.33. Similarly, when the (SOC, OCV) data at an SOC of 40% is acquired, the discrete degree is calculated as 7.14. When (SOC, OCV) data is obtained at an SOC of 30%, the discrete degree is calculated as 6.25. Further, when (SOC, OCV) data is acquired at an SOC of 10%, the discrete degree is calculated as 5.00.

  From the viewpoint of the degree of discreteness of data, it is most desirable to acquire data at an SOC of 10%. However, in order to acquire data when the SOC is 10%, it is necessary to perform charging / discharging between the storage battery units until the SOC becomes 10% from the current 60%. Therefore, it takes a longer time to acquire data as compared to the case of acquiring other SOC data. Moreover, it may not be preferable to repeat a large amount of charge transfer between storage batteries. Therefore, the control calculation unit 230 selects the next acquisition target SOC in consideration of the operation time including the time required for the charge transfer in addition to the discrete degree.

Figure 9 is a diagram showing the information for calculating the time T _M required for charge transfer. The horizontal axis represents the SOC in percent (%), and the vertical axis represents the time _{T M.} The mapping line 700 indicates the time required for the SOC to reach the value indicated by the horizontal axis due to charging / discharging between the storage battery units from the state where the SOC is 60%. As shown, T _M is substantially proportional to the magnitude of ΔSOC of the difference before and after the SOC of charge transfer. As an example, the time T _M when the magnitude of the ΔSOC is 10%, at least several minutes or more, may be 10 minutes or more in many cases. BATT information storage unit 233, as information indicating the mapping line 700 may store a mapping table M that maps to the ΔSOC time _{T M.}

The control calculation unit 230 refers to the mapping table stored in the BATT information storage unit 233 and calculates the time T _M from ΔSOC. For example, the control calculation unit 230 calculates the time T _MΔ20 required until the SOC becomes 40% due to charge / discharge between the storage battery units from the current SOC of 60%, the 20% ΔSOC, and the mapping table M Use to calculate.

The operation time includes time T _d required to acquire (SOC, OCV) data after reaching the acquisition target SOC in addition to the time required to move the charge. _Td is the time required to acquire one OCV measurement value from the timing when the SOC reaches the acquisition target SOCt, which is the SOC from which data is acquired. _Td includes the time to wait for the time change of the terminal voltage of the storage battery to stabilize. In many cases, the terminal voltage in the open circuit state after charging and discharging of the storage battery changes relatively slowly with time, and a certain time is required until the time change of the terminal voltage becomes substantially negligible. Therefore, the control calculation unit 230 waits for the time when the time change of the terminal voltage of the storage battery is stabilized, and acquires the measured value of the terminal voltage.

Therefore, at least the time _Td is required from the timing when the SOC reaches the acquisition target SOCt until the measurement value of one OCV is acquired. Therefore, the control calculation unit 230 calculates the operation time T _t by T _t = T _M + T _d . The control calculation unit 230 calculates an operation time T _t for each SOC for which (SOC, OCV) data is not acquired.

  As described above, the control calculation unit 230 calculates the discreteness and the operation time for each SOC. And control operation part 230 computes an evaluation value for every SOC using an evaluation function from discreteness and operation time for every SOC. The evaluation value is used to select the next SOC to be acquired.

  FIG. 10 shows an example of the discreteness, operation time, and evaluation value calculated for each SOC. The control calculation unit 230 normalizes the discrete degree and the operation time by dividing by the respective maximum values. Then, the control calculation unit 230 inputs the standardized discrete degree and the standardized operation time into an evaluation function having the discrete degree and the operation time as parameters, and calculates an evaluation value.

  As an example, the evaluation function may be a function that performs weighted addition. For example, when the standardized discrete degree is <w> and the standardized operation time is <Tt>, the evaluation function is a function that outputs an evaluation value by α × <Tt> + β × <w> good.

  FIG. 10 shows the evaluation values obtained by the evaluation function when α = 0.4 and β = 0.6. The control calculation unit 230 selects the next acquisition target SOC from the calculated evaluation value. The degree of discreteness described with reference to FIG. 8 indicates that the smaller the value, the greater the degree of discreteness of data. In addition, the operation time described with reference to FIG. 9 indicates that the smaller the value, the faster the data can be acquired. Therefore, the control calculation unit 230 selects the SOC for which the smaller evaluation value is calculated as the next acquisition target SOC with higher priority. In the example of FIG. 10, 40% for which the smallest evaluation value is calculated is selected as the next acquisition target SOC.

  Note that β is preferably larger than α. In other words, it is desirable to make the weight of discreteness in the evaluation value larger than the weight of operation time. Accordingly, it can be expected that data capable of selecting a SOC-OCV curve with higher accuracy can be acquired promptly and sufficiently while suppressing loss caused by frequent charge transfer between power storage units.

  FIG. 11 is a flowchart for determining the SOC-OCV curve. The flow starts when the battery ECU 130 receives an instruction for determining the SOC-OCV curve from the control unit of the transport device 10. Here, a case where the first storage battery 111 is selected as the target power storage unit and the SOC-OCV curve of the first storage battery 111 is determined will be described.

  In step S101, the control calculation unit 230 determines whether or not the OCV of the first storage battery 111 can be acquired. For example, when the PDU 141 requests power supply, the request is prioritized and the first switch 114 and the third switch 133 are closed, so it is determined that the OCV cannot be acquired. In this case, it waits until it can be acquired.

If it is determined that can be acquired OCV, control calculation unit 230 proceeds to step S102, and transmits a switching instruction signal CW ₁ to the first switch 114 is opened. Then, to get the _{V 1} from the first voltage sensor 112, to the voltage value and _{O 0} the initial OCV. In step S103, the control calculation unit 230 determines whether the acquired O ₀ is included in the range of the reference OCV. Specifically, the control calculation unit 230 acquires the reference information of the first storage battery 111 from the BATT information storage unit 233, and refers to the range O _{min to} O _max of the standard OCV. _Then, it is determined whether satisfies the relation _{O min ≦ O 0 <O max} .

If it is determined that the acquired O ₀ is not included in the range of the reference open circuit voltage, the process proceeds to step S104, and the control calculation unit 230 performs charge / discharge between the storage battery units. Specifically, the control calculation unit 230 transmits the opening / closing instruction signals CW ₁ , CW ₂ , and CW ₃ to the respective switches, the first switch 114 and the second switch 124 are closed, and the third switch 133 is closed. Is opened. Then, control signals CV ₁ and CV ₂ are transmitted to the respective VCUs, and the converted voltage value of the second VCU 132 is set higher than the converted voltage value of the first VCU 131. Then, since the 2nd storage battery 121 will be in a discharge state and the 1st storage battery 111 will be in a charging state, a fixed electric charge will move from the 2nd storage battery 121 to the 1st storage battery 111. The control calculation unit 230 can change the amount of electric charge to be moved by adjusting the open / close time of each switch or adjusting the conversion voltage value of each VCU. Further, the control calculation unit 230 may determine the amount of electric charge to be moved according to the difference between the acquired O ₀ and the reference OCV range O _{min to} O _max .

In addition, when performing charging / discharging between storage battery parts using two VCUs, only one VCU may perform PWM control and the other VCU may perform direct connection control. The direct connection control is a control in which only the high-side switch of the DC / DC converter is closed and current is allowed to pass without being stepped up or down. When direct control is performed, the control signals CV ₁ and CV ₂ are designated “0” as the command value for the conversion voltage.

  When the charging / discharging between the storage battery units is completed in step S104, the process returns to step S101 again, and this loop is repeated until the condition of step S103 is satisfied. If the condition of step S103 is satisfied, the process proceeds to step S105.

In step S105, the control calculation unit 230 stores (SOC _full , OCV) data in the internal storage unit. Here, SOC _full is a value corresponding to 100% SOC. The SOC _full may be 100%. Also, SOC _full may be a value not less than S _{min and not} more than S _max . For example, SOC _full = (S _min + S _max ) / 2 may be set.

  From step S107, it is the process which repeats charging / discharging between storage battery parts, and acquires (SOC, OCV) data. In step S107, the control calculation unit 230 determines whether the OCV can be acquired. This determination is the same as the determination in step S101. If the OCV cannot be obtained, the process waits until it becomes possible. If the OCV can be acquired, the process proceeds to step S108, the SOC to be acquired next is determined, and the data of (SOC, OCV) is acquired in step S109. The process in step S108 will be described later.

  The control calculation unit 230 proceeds to step S110, and determines whether or not OCV data has been acquired in all the SOCs to be acquired. If it is determined that it has not yet been acquired, the process proceeds to step S111.

  Step S111 is executed at the time of starting the process of acquiring the next (SOC, OCV) data. In step S111, it is determined whether or not data for all SOCs to be acquired has been acquired within a predetermined time. For example, the control calculation unit 230 determines whether or not a predetermined time has elapsed from the acquisition time of the data stored in step S105. For example, 7 days is set as the specified time. The specified time can be changed according to the travel distance, environmental temperature, accuracy required for the SOC-OCV curve, and the like. If it is determined that the specified time has not elapsed, the control calculation unit 230 returns to step S107 and sequentially acquires data in the acquisition target SOC. If it is determined that the specified time has elapsed, the process returns to step S101. In this case, the previously acquired (SOC, OCV) data is discarded. By discarding the old data in this way, the SOC-OCV curve is not determined with data acquired in different deterioration states, so that the accuracy of the determined SOC-OCV curve is improved.

  If it is determined in step S110 that data has been acquired for all the SOCs to be acquired, the process proceeds to step S112, and the control calculation unit 230 determines the SOC-OCV curve from the acquired plurality of data. Specifically, the control calculation unit 230 reads the reference data of the first storage battery 111 from the BATT information storage unit 233, and most closely matches the acquired plurality of data from the SOC-OCV curve for each capacity maintenance rate. Choose the one that increases. Then, the SOC-OCV curve thus selected is stored in the confirmed line holding unit 234 as a confirmed SOC-OCV curve. When the determined SOC-OCV curve is stored in the confirmed line holding unit 234, the control calculation unit 230 ends the series of processes.

  FIG. 12 is a flowchart until determining the SOC to be acquired next. The flow shown in FIG. 12 is applied to step S108 in the flow of FIG.

In step S _< b _> 301, the control calculation unit 230 acquires SOC _n that is the current SOC of the first storage battery 111. The processes from S311 to S319 are processes for calculating the time T _i required to acquire (SOC, OCV) data for each SOC to be acquired by performing the iterative process for _i . In order to simplify the explanation, i in this flowchart shows the SOC to be acquired. For the purpose of showing the meaning of i in an easy-to-understand manner, i (SOC) may be indicated. The repetitive processing from S311 to S319 indicates a case where data in the SOC determined in increments of 10% is obtained for SOC in the range of 10% to 100%.

In step S313, control operation unit 230 calculates ΔSOC, which is the difference between current SOC _n and i (SOC). Specifically, control arithmetic unit 230 calculates ΔSOC by ΔSOC = i (SOC) −SOC _n . In step S315, the control calculation unit 230 calculates an operation time T _ti . Specifically, as described with reference to FIG. 9 and the like, the control calculation unit 230 acquires the charge transfer time M (ΔSOC) calculated with reference to the mapping table M and the time required to acquire the data. The operation time T _ti is calculated by the sum with T _d .

  In step S317, the control calculation unit 230 calculates the discreteness of the measured SOC obtained when it is determined that the OCV measurement at i (SOC) has been performed. For example, as described with reference to FIG. 8 and the like, the control calculation unit 230 divides the number of (SOC, OCV) data obtained when the OCV measurement is performed by the range of the measured SOC. To calculate the discreteness of the SOC.

  When the iterative process from step S311 to step S319 is completed, in step S331, the control calculation unit 230 normalizes the calculated operation times. For example, the control calculation unit 230 normalizes each calculated operation time with the maximum value of the operation time.

  In step S333, the control calculation unit 230 normalizes the calculated discrete degrees. For example, the control calculation unit 230 normalizes each calculated discrete degree with the maximum value of the discrete degree.

  In step S335, the control calculation unit 230 calculates an evaluation value for the unacquired SOC using the normalized operation time and the normalized discrete degree. For example, as described with reference to FIG. 10 and the like, the control calculation unit 230 calculates an evaluation value by applying an evaluation function to the normalized operation time and the normalized discrete degree.

  In step S331, the control calculation unit 230 determines the SOC to be acquired next. Specifically, the control calculation unit 230 determines the SOC to be acquired next based on the evaluation value calculated in S335. More specifically, the control calculation unit 230 determines the SOC for which the minimum evaluation value has been calculated as the SOC to be acquired next. After S337, the process proceeds to step S109 in the flow of FIG.

  As described with reference to FIGS. 10, 12, etc., the control calculation unit 230 determines the SOC having the smallest evaluation value among the plurality of SOCs to be acquired as the next SOC to be acquired. Thereby, the accuracy of the SOC-OCV curve can be increased (SOC, OCV) data can be acquired quickly.

  In connection with FIG. 8 and the like, as an example of the degree of discreteness of the SOC, a case where the SOC range of collected data is divided by the number of SOCs for which data has been acquired has been described. The discreteness of the SOC is not limited to this. Various values representing the degree of discreteness of the SOC, such as the variance of the SOC from which data has been acquired, the density of the SOC from which data has been acquired, and the difference between adjacent SOCs in the coordinates of the SOC from which data has been acquired It may be calculated using various parameters.

  In addition, when selecting the next acquisition target SOC, it has been described that the SOC to be acquired next is selected from all the SOCs for which data has not been acquired among the SOCs predetermined as acquisition targets. . However, the SOC to be acquired next may be selected from some SOCs for which data has not been acquired from among SOCs determined in advance as acquisition targets. For example, the SOC range to be acquired next may be limited to a specific range. For example, the SOC range to be acquired next may be limited to less than a predetermined value. As an example, in the situation shown in FIG. 8, the SOC to be acquired next may be selected from SOCs less than 40% out of the SOCs predetermined as acquisition targets. In this case, for example, 30% may be selected as the next acquisition target SOC based on the evaluation value shown in FIG.

  In the above flow, the procedure for determining the SOC-OCV curve of the first storage battery 111 has been described, but the procedure for selecting the second storage battery 121 as the target storage battery and determining the SOC-OCV curve of the second storage battery 121 is the same. It is. If the SOC-OCV curves of the respective storage batteries are determined, the determined line holding unit 234 stores the two SOC-OCV curves. Further, after determining the SOC-OCV curve of one storage battery, the SOC-OCV curve of the other storage battery may be determined, or (SOC, OCV) data for each storage battery at each charge / discharge between the storage battery units. , Two SOC-OCV curves can be determined in parallel. In addition, when determining in order, it is good to determine the SOC-OCV curve of a high output type battery with priority over a high capacity type battery. Also, the SOC-OCV curve update frequency is preferably increased for the high-power battery. As described above, since the fluctuation of the degree of deterioration influence of the high-power battery on the SOC is larger than that of the high-capacity battery, it is more accurate to charge and discharge while suppressing the deterioration of the high-power battery. This is because it is necessary to always have a high SOC-OCV curve. In addition, because of its characteristics, the SOC of a high-capacity battery that charges and discharges constant power continuously can be estimated by a current integration method, but a high-power battery that instantaneously charges and discharges large power is This is because the SOC can be estimated with higher accuracy by using the SOC-OCV curve than by the current integration method.

In the above embodiment, the (SOC, OCV) data is acquired by adjusting the OCV to be included in the reference OCV, but the (SOC, OCV) data is acquired by adjusting the SOC to be included in the reference SOC. You may do it. In this case, so that SOC falls within a range _(S min _{~S max)} of _{S R,} it may be determined based on the electric quantity of charge to move the storage battery unit mesenchymal discharge _{C full.}

  Further, in the above embodiment, the reference area is adjusted so that at least one (SOC, OCV) data is included, but without such adjustment, a plurality of (SOCs) not included in the reference area are included. , OCV) data may be collected and the SOC-OCV curve having the highest degree of coincidence in the data group may be selected from the reference data and determined. In this case, the accuracy is lower than when the reference area includes (SOC, OCV) data, but the SOC-OCV curve can be determined more easily.

  In the above embodiment, the BATT information storage unit 233 stores the reference data of each storage battery, and performs matching processing with each SOC-OCV curve of the reference data, thereby determining the current SOC-OCV curve. I am letting. However, an approximate curve or approximate line may be calculated from a plurality of (SOC, OCV) data without referring to the reference data, and the approximate curve or approximate line may be determined as the SOC-OCV curve. The approximate curve or the approximate line may be calculated by fitting based on the least square method or the like. Note that an average value of OCV may be calculated for each SOC, and an approximate curve or an approximate line may be calculated based on the calculated average value of OCV. An approximate straight line of each section may be calculated by connecting adjacent SOCs with a straight line with respect to coordinates (average value of SOC, OCV) on the SOC-OCV plane. When the coordinates (average values of SOC and OCV) are 3 or more, a polygonal line as a set of approximate straight lines is calculated. Since the SOC-OCV curve of each capacity maintenance rate in the reference data is representative data of the storage battery of that type prepared by, for example, a battery manufacturer, the reliability is high. However, since the variation of individual products is not supported, the variation is an error. However, if an approximate curve or an approximate straight line is calculated from actually measured (SOC, OCV) data, it can be said that it is a raw SOC-OCV curve absorbed up to individual variations. Therefore, there is a possibility that it can be used as a more accurate SOC-OCV curve. In addition, depending on the type of storage battery, there may be a case where the reference region does not exist. In such a case, an approximate curve or approximate straight line calculated from actually measured (SOC, OCV) data and reference data are used. In combination, the SOC-OCV curve can be determined. Specifically, among the SOC-OCV curves of the respective capacity maintenance ratios included in the reference data, those having a shape closest to the approximate curve or the approximate straight line calculated from the actually measured (SOC, OCV) data, Confirm as SOC-OCV curve.

  When selecting and confirming the SOC-OCV curve from the reference data, it is associated with the capacity maintenance rate, so that the degree of deterioration of the storage battery at that time can also be grasped. On the other hand, when an approximate curve or approximate straight line is calculated from actually measured (SOC, OCV) data, the degree of deterioration cannot be grasped although there is an expectation that accuracy will increase. Therefore, the SOC-OCV curve determination method may be selected in accordance with the circumstances required by the system. Further, for example, in order to perform an error check of the acquired (SOC, OCV) data, both may be used together.

  Further, in the above embodiment, as described with reference to FIG. 11 in particular, when a predetermined number of coordinates cannot be acquired within a predetermined time, all (SOC, OCV) data are discarded. The procedure for re-processing from the beginning was explained. However, the old (SOC, OCV) data may be individually excluded, and a plurality of (SOC, OCV) data used for the matching process may be limited to those acquired within a predetermined time. Further, the criterion for selecting (SOC, OCV) data used for the matching process is not limited to the time when the (SOC, OCV) data is acquired. For example, in charge / discharge between storage battery units, when the accumulated amount of electric charge to be moved exceeds a predetermined amount of electricity, the old (SOC, OCV) data may be excluded in order. In this case, the next integrated amount is updated to the integrated amount from the time when the second oldest (SOC, OCV) data is acquired. In addition, you may change the electric quantity used as a reference | standard according to the precision etc. which are required for a travel distance, environmental temperature, a SOC-OCV curve.

  In addition, a transport apparatus is not restricted to an electric vehicle. The transportation device may be a vehicle such as a hybrid vehicle or a train including a power supply device and an internal combustion engine. The transportation device is not limited to a vehicle, and includes various devices that move objects on land, in the air, on water, or in water, such as an aircraft or a ship equipped with a power supply device. The transportation equipment is a concept including various transportation equipment provided with a power supply device.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Transportation apparatus, 100 Electrical storage apparatus, 101 1st electrical storage module, 102 2nd electrical storage module, 103 Charging / discharging circuit module, 111 1st storage battery, 112 1st voltage sensor, 113 1st current sensor, 114 1st switch, 121 1st 2 storage batteries, 122 second voltage sensor, 123 second current sensor, 124 second switch, 130 battery ECU, 131 first VCU, 132 second VCU, 133 third switch, 142 third voltage sensor, 141 PDU, 151 charge converter, 152 Power receiving unit, 153 External power supply, 230 Control operation unit, 231 ΔSOC calculation unit, 232 Timekeeping unit, 233 BATT information storage unit, 234 Confirmed line holding unit, 235 SOC response unit, 290 Recording medium, 700 Mapping line, 701, 702 , 703, 704 Code, 770, 780 SOC-OCV curve

Claims (20)

A first power storage unit;
A second power storage unit;
A charge / discharge circuit responsible for charge / discharge between the first power storage unit and the second power storage unit;
A control unit for controlling the charge / discharge circuit,
The controller is
At least one of the first power storage unit and the second power storage unit is a target power storage unit,
Obtain the target SOC and target OCV, which are the charging rate and open circuit voltage of the target power storage unit,
Using the charge transfer between the first power storage unit and the second power storage unit, the data including the target SOC and the target OCV is converted into a discrete state with respect to the SOC of the collected data that is a set of the data and the target SOC. Collected in the order derived from the evaluation function based on
The power supply apparatus characterized by estimating the correlation information of SOC and OCV of the said object electrical storage part based on the said some data. The control unit derives uncollected data that is a set of the data not collected based on the collected data,
The power supply apparatus according to claim 1, wherein the evaluation function is based on the discrete state when an uncollected SOC that is an SOC included in the uncollected data is collected. The power supply apparatus according to claim 2, wherein the evaluation function is based on a change amount of the discrete state when the uncollected SOC is collected. The power supply apparatus according to claim 2, wherein the evaluation function evaluates higher the data including the uncollected SOC that increases the discrete state when collected. 5. The power supply device according to claim 2, wherein the evaluation function is further based on an operation time including a time required for the charge transfer calculated from a difference between the uncollected SOC and the target SOC. The power supply device according to claim 5, wherein the operation time includes a time required for the time change of the voltage of the target power storage unit to be stabilized after the charge transfer. The power supply apparatus according to claim 5, wherein the evaluation function evaluates higher as data including the uncollected SOC with a shorter operation time. The power supply apparatus according to claim 5, wherein the evaluation function evaluates the discrete state more strongly than the operation time. The control unit includes the SOC of the target power storage unit within a range of a reference SOC that is an SOC in which a difference in OCV with respect to the same SOC is equal to or less than a threshold value in a plurality of deterioration states of the target power storage unit, or the reference SOC The target SOC is acquired based on a charge transfer amount to the target power storage unit from when the SOC of the target power storage unit is included in a range of a reference OCV that is an OCV corresponding to The power supply device according to item 1. The control unit includes a reference SOC that is an SOC in which a difference between OCVs for the same SOC is equal to or less than a threshold value in a plurality of deterioration states of the target power storage unit, and a reference OCV that is an OCV corresponding to the reference SOC. The power supply device according to claim 1, wherein the data is collected so as to be included as the target OCV. When the SOC of the target power storage unit before performing the charge transfer is not included in the range of the reference SOC, or when the OCV of the target power storage unit before performing the charge transfer is equal to the reference OCV When not included in the range, prior to the charge transfer, the SOC of the target power storage unit is included in the range of the reference SOC, or the OCV of the target power storage unit is included in the range of the reference OCV. The power supply device according to claim 9 or 10, wherein charge / discharge is performed between one power storage unit and the second power storage unit. The control unit includes a storage unit that stores in advance correlation information between SOC and OCV in a plurality of deterioration states of at least one of the first power storage unit and the second power storage unit,
The control unit has a degree of fitness for the plurality of data including the target SOC and the target OCV among the correlation information of the SOC and the OCV in the plurality of deterioration states of the target power storage unit stored in the storage unit. The power supply device according to any one of claims 1 to 11, wherein higher correlation information is selected with higher priority as the estimated correlation information. The power supply device according to any one of claims 1 to 11, wherein the control unit estimates the correlation information based on an approximate curve or an approximate line for the plurality of data including the target SOC and the target OCV. At least one of the first power storage unit and the second power storage unit supplies power to the drive unit,
The charge / discharge circuit is responsible for charge / discharge between the first power storage unit, the second power storage unit, and the drive unit,
The control unit controls the charge / discharge circuit so that the first power storage unit and the second power storage unit do not perform charge / discharge between the drive unit and the first power storage unit while performing the charge transfer. The power supply device according to any one of the above. When the control unit receives an SOC inquiry of the power storage unit for which the correlation information has already been estimated among the first power storage unit and the second power storage unit, the control unit The power supply device according to any one of claims 1 to 14, wherein, based on the estimated correlation information, the SOC of the power storage unit in which the correlation information is estimated is calculated and responded. The power supply device according to any one of claims 1 to 15, wherein the first power storage unit is inferior in energy density and output density compared to the second power storage unit. The power supply device according to claim 16, wherein the control unit preferentially selects the first power storage unit as the target power storage unit over the second power storage unit.   The transport equipment which has a power supply device of any one of Claims 1-17. A first power storage unit;
A second power storage unit;
An estimation method for estimating correlation information between SOC and OCV, which are a charge rate and an open-circuit voltage of a power supply device including a charge / discharge circuit responsible for charge / discharge between the first power storage unit and the second power storage unit,
Setting at least one of the first power storage unit and the second power storage unit as a target power storage unit;
Obtaining a target SOC and a target OCV that are SOC and OCV of the target power storage unit;
Using the charge transfer between the first power storage unit and the second power storage unit, the data including the target SOC and the target OCV is converted into a discrete state with respect to the SOC of the collected data that is a set of the data and the target SOC. Collecting in an order derived from an evaluation function based on
Estimating the correlation information between the SOC and the OCV of the target power storage unit based on a plurality of the data. A first power storage unit;
A second power storage unit;
A program for estimating correlation information between SOC and OCV which are a charge rate and an open circuit voltage of a power supply device including a charge / discharge circuit responsible for charge / discharge between the first power storage unit and the second power storage unit. ,
Setting at least one of the first power storage unit and the second power storage unit as a target power storage unit;
Obtaining a target SOC and a target OCV that are SOC and OCV of the target power storage unit;
Using the charge transfer between the first power storage unit and the second power storage unit, the data including the target SOC and the target OCV is converted into a discrete state with respect to the SOC of the collected data that is a set of the data and the target SOC. Collecting in an order derived from an evaluation function based on
The program for making a computer perform the step which estimates the correlation information of SOC of the said object electrical storage part and OCV based on the said some data.

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