JP2017138241A - Power storage device, transportation apparatus having power storage device, failure determination method, and failure determination program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly recognize a failure in a power storage battery since influence, such that a fail-safe action is needed, is given to the whole device when the power storage battery is failed and, for example, the power storage battery is utilized in a transportation apparatus.SOLUTION: When a plurality of coordinates on the two-dimensional plane composed of SOC and OCV of a first power storage part are specified, using OCV of the first power storage part before and after power movement between power storage parts, which is charge and discharge between the first power storage part and a second power storage part, and the charge and discharge amount of power movement, and in a stage where a first correlation information being a relationship of SOC and OCV of the first power storage part is confirmed, the specified coordinates are separated from an approximate curve or an approximate straight line formed by the other coordinates specified until then while exceeding a predetermined amount, a control part diagnoses that the first power storage part is in a failure state.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a power storage device, transport equipment having the power storage device, a failure diagnosis method, and a failure diagnosis program.

In a system including a plurality of storage batteries, a technique for grasping the relationship between the remaining capacity and the open-circuit voltage by charging and discharging between the storage batteries is known.
[Prior art documents]
[Patent Literature]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2008-220080

  When the storage battery fails, for example, when the storage battery is used for transportation equipment, the entire apparatus is affected by the need for fail-safe action. Therefore, the failure of the storage battery needs to be recognized promptly.

  A power storage device according to a first aspect of the present invention includes a first power storage unit, a first current sensor that detects a current flowing into and out of the first power storage unit, and a first voltage sensor that detects a voltage of the first power storage unit. A first power storage module, a second power storage module including 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 a charge control unit that controls the charge / discharge circuit The controller includes the OCV of the first power storage unit before and after the power transfer between the power storage units due to the charge / discharge between the first power storage unit and the second power storage unit, and the charge / discharge amount of the power transfer. And identifying a plurality of first coordinates in a two-dimensional plane composed of the SOC and OCV of the first power storage unit, and identifying the first correlation information that is the relationship between the SOC and OCV of the first power storage unit. The first coordinate is the other first specified so far If deviate beyond a predetermined amount from an approximate curve or an approximate straight line is formed by a target, and wherein the diagnosing faults state of the first power storage unit.

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

  A failure diagnosis method according to a third aspect of the present invention includes a first power storage unit, a first current sensor that detects a current flowing into and out of the first power storage unit, and a first voltage sensor that detects a voltage of the first power storage unit. A first power storage module provided; a second power storage module provided with 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. A failure diagnosis method for a power storage device having a charge / discharge circuit module, comprising: a power transfer step of charging / discharging between a first power storage unit and a second power storage unit; an OCV of the first power storage unit; Based on the discharge amount, a plot step for specifying the first coordinate in the two-dimensional plane composed of the SOC and OCV of the first power storage unit, and a plurality of first coordinates specified by repeating the power transfer step and the plot step a plurality of times Then, a confirmation step for confirming the first correlation information, which is the relationship between the SOC and the OCV of the first power storage unit, and the first coordinate specified during the processing of the confirmation step are the other first specified so far. And a diagnostic step of diagnosing a failure state of the first power storage unit when it is detected that the deviation exceeds a predetermined amount from the approximate curve or approximate line formed by the coordinates.

  A failure diagnosis program according to a fourth aspect of the present invention includes a first power storage unit, a first current sensor that detects a current flowing into and out of the first power storage unit, and a first voltage sensor that detects a voltage of the first power storage unit. A first power storage module provided; a second power storage module provided with 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. A failure diagnosis program for a power storage device having a charge / discharge circuit module, comprising: a power transfer step of charging / discharging between a first power storage unit and a second power storage unit; an OCV of the first power storage unit; A plurality of plot steps that specify the first coordinates in the two-dimensional plane composed of the SOC and OCV of the first power storage unit based on the discharge amount, and a plurality of times that are identified by repeating the power transfer step and the plot step a plurality of times. Based on the first coordinate, a confirmation step for confirming the first correlation information that is the relationship between the SOC and the OCV of the first power storage unit, and the first coordinate specified during the processing of the confirmation step has been identified so far When it is detected that a deviation from an approximate curve or approximate straight line formed by other first coordinates exceeds a predetermined amount, the computer is caused to execute a diagnosis step of diagnosing a failure state of the first power storage unit.

  A power storage device according to a fifth aspect of the present invention includes a first power storage module including a first power storage unit, a second power storage module including a second power storage unit, and charge / discharge between the first power storage unit and the second power storage unit. A charge / discharge circuit module that performs power transfer between power storage units by means of the charge / discharge circuit module, which obtains a plurality of first data representing sets of OCV values and SOC values in the first power storage unit by repeating power transfer In the step of determining the first correlation information representing the relationship between the SOC and the OCV of the first power storage unit based on the plurality of acquired first data, the identified first data has been identified so far When it is determined that the correlation deviates from the correlation obtained from the other first data, the failure of the first power storage unit is estimated.

  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 principal part block diagram of the transport 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 a figure for demonstrating the plotting order of a coordinate. It is an internal block diagram of battery ECU. It is a flowchart until it determines a SOC-OCV curve. It is a figure explaining the concept of failure detection. It is a flowchart of a failure detection.

  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 principal 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 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 is made of, 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 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 It consists of 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-power battery that has a higher output weight density, which is output power per unit weight, than the second storage battery 121. On the other hand, the second storage battery 121 is a so-called high capacity battery in which the energy weight density, which is stored power per unit weight, is larger than that of the first storage battery 111.

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 BATT 111 and the second BATT 121 and the converter type, the battery can be used as a single battery 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 capacity maintenance rate is the amount of power that can be stored when new (100%) at full charge. This is a percentage of the amount of electricity that can be stored. For example, a storage battery that can store only 80% of the initial stored power 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. In addition, SOC here is a charging rate when the stored electric energy of full charge in the state in which deterioration 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, the SOC when the capacity maintenance rate is 80% is 80%, while the SOC when the capacity maintenance rate is 60% is 70%. Many accumulator batteries are generally known to exhibit this tendency.

  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. However, 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. In this case, for example, when SOC-OCV curve is not desired side of the battery confirm is the first battery 111 by monitoring the voltage _{V 1} of the first voltage sensor 112, a current _{I 1} of the first current sensor 113 Thus, the increase or decrease of the SOC of the first storage battery 111 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 charge / discharge between the storage battery parts 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 / discharging between the storage battery units, the battery ECU 130 obtains the SOC-OCV curve having the highest degree of coincidence with respect to these coordinates (the smallest deviation of each coordinate) from the reference data. Select and confirm by matching process. The SOC-OCV curve selected and determined at this time becomes the most probable SOC-OCV curve at that time. 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, the SOC-OCV curve can be specified 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 from the current sensor from time t _n to time t _{n + 1} , and ΔAh represents the amount of power that has changed during this time. Further, C _full is the amount of power at the time of full charge at the previous specific time. Each time C _full is specified, its value is stored in the storage unit.

  FIG. 6 is a diagram for explaining the coordinate plotting order. There are roughly two procedures for repeating charging and discharging between the storage battery units. First, as shown in FIG. 6A, the first storage battery 111 → the second storage battery 121 → the first storage battery 111 → the second storage battery →... It is a procedure to move. By controlling in this way, charge and discharge can be repeated in the SOC band (about 30% to about 70%) with little damage to the storage battery, so that the progress of deterioration can be suppressed. The second is a procedure for limiting the movement of power in one direction, as shown in FIG. Controlling in this way makes it easy to control charging / discharging between storage battery parts.

  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. 7 is an internal block diagram of battery ECU 130.

  As shown in the figure, the battery ECU 130 has a ΔSOC calculation unit 231, a time measurement unit 232, a BATT information storage unit 233, and a confirmed line holding unit 234, with a control calculation unit 230 responsible for the entire control and calculation as a center. Processing is performed until the SOC-OCV curve is determined by these functional blocks. In addition to this, an SOC response unit 235 and a failure determination unit 236 are mainly included.

The control calculation unit 230 is configured by, for example, an MPU, and controls the entire power storage device 100 according to a program stored in the storage unit. The control calculation unit 230 transmits the 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 are transmitted to the first VCU 131 and the second VCU 132 in order to adjust the converted voltages. The ΔSOC calculation unit 231 obtains V ₁ as OCV from the first voltage sensor 112 and plots I ₁ from the first current sensor 113 to calculate ΔSOC when plotting coordinates in the first storage battery 111. Similarly, the time plot of coordinates in the second battery 121 acquires _{V 2} as the OCV from the second voltage sensor 122, a second current sensor 123 to obtain the _{I 2,} and calculates the [Delta] SOC. 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 coordinate Sp is acquired, and excludes it from the target of the matching process when the coordinate has passed a predetermined elapsed time.

  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 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.

  The failure determination unit 236 verifies the abnormality of the acquired coordinates Sp and determines whether or not a failure has occurred in the power storage device 100. If it is determined that there is a failure, a failure signal is transmitted to the outside. At this time, the transport device 10 executes an emergency treatment according to the failure signal. The failure determination will be described in detail later.

  FIG. 8 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 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 Ot ₀ is the initial OCV. In step S103, the control calculation unit 230 determines whether or not the acquired Ot 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 or not the relationship of O _min ≦ Ot ₀ <O _max is satisfied.

If it is determined that the acquired Ot 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 energy moves from the 2nd storage battery 121 to the 1st storage battery 111. The control calculation unit 230 can change the amount of power to be moved by adjusting the opening / closing time of each switch or adjusting the conversion voltage value of each VCU. Further, the control calculation unit 230 may determine the amount of power to be moved according to the difference between the acquired Ot 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 plots SP ₀ on the SO plane as described with reference to FIG. In step S106, 1 is substituted into the increment variable n.

From step S107, a process of acquiring the coordinates Sp _n repeat battery unit mesenchymal discharge. 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 acquisition of OCV is possible, it will progress to step S108 and the control calculating part 230 will perform charging / discharging between storage battery parts. In step S109, the first switch 114 is opened, and Ot ₁ that is OCV is acquired from the output of the first voltage sensor 112. Subsequently, in step S110, the control calculation unit 230 causes the ΔSOC calculation unit 231 to calculate ΔSOC, and calculates St ₁ as the SOC according to the procedure described with reference to FIG. In step S111, the control calculation unit 230 plots Sp ₁ on the SO plane. At this time, the time at which the coordinate Sp ₁ is acquired is acquired from the time measuring unit 232 and stored in association with the coordinate Sp ₁ . When this one plotting process is completed, the increment variable n is incremented by 1 in step S112.

Control calculation unit 230 proceeds to step S113, repeating number n of the plotted coordinates it is determined whether reaches the predetermined number n ₀ determined in advance. If it is determined that it has not yet reached, the process proceeds to step S114.

Step S114 is performed at the time of starting the process of acquiring the next coordinate Sp _n. In step S114, the control calculation unit 230 determines whether or not a predetermined time has elapsed from the acquisition time of the coordinate Sp _n−1 that is the previous plot. 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. Control calculation unit 230, if it is determined not to have elapsed predetermined time, returns to step _S107, Sp 2, _Sp 3, acquires Sp 4 _... sequentially coordinates. If it is determined that the specified time has elapsed, the process returns to step S101. In this case, all the coordinates Sp on the SO plane acquired so far are discarded. By discarding the old coordinates Sp in this way, the SOC-OCV curve is not fixed at the coordinates Sp acquired in different deterioration states, so that the accuracy of the determined SOC-OCV curve is improved.

In step S113, if it is determined to have reached the prescribed number _{n 0} of the number n of the coordinates are predetermined plotted repeatedly, the process proceeds to step S115, the control arithmetic unit 230, SOC-OCV curve from a plurality of coordinates Sp obtained Confirm. 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 coordinates Sp from the SOC-OCV curves for the respective capacity maintenance rates. Choose the one with the highest degree. 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.

  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 determining the SOC-OCV curve of the second storage battery 121 is the same. If the SOC-OCV curves of the respective storage batteries are determined, the determined line holding unit 234 stores the two SOC-OCV curves. Moreover, after confirming the SOC-OCV curve of one storage battery, you may confirm the SOC-OCV curve of the other storage battery, and if coordinate Sp is acquired with each storage battery at every charge / discharge between storage battery parts. 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, Sp ₀ is acquired by adjusting the OCV to be included in the reference OCV. However, Sp ₀ may be acquired by adjusting the SOC to be included in the reference SOC. In this case, so that SOC falls within the range of _{S R (S min ~S max)} , it may be determined based on the amount of power to move the storage battery unit mesenchymal discharge _{C full.}

In the above embodiment, the reference region is adjusted so that at least one coordinate (Sp ₀ ) is included, but a plurality of coordinates Sp are collected without performing such adjustment, and the coordinate group is collected. The SOC-OCV curve having the highest degree of coincidence may be selected from the reference data and determined. In this case, the accuracy is reduced compared to the case where Sp ₀ is included in the reference region, 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 coordinates Sp without referring to the reference data, and the approximate curve or approximate line may be determined as an SOC-OCV curve. 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 line is calculated from the actually measured coordinates Sp, it can be said that it is a raw SOC-OCV curve that has absorbed even individual variations. Therefore, there is a possibility that it can be used as a more accurate SOC-OCV curve. Further, depending on the type of storage battery, there may be a case where the reference region does not exist. In such a case, the approximate curve or the approximate straight line calculated from the actually measured coordinates Sp and the reference data are used together. An 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 the shape closest to the approximate curve or the approximate straight line calculated from the actually measured coordinates Sp are obtained as the SOC-OCV curve. Confirm as

  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 line is calculated from the actually measured coordinates Sp, the degree of deterioration cannot be grasped although there is an expectation that the 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 coordinates Sp, both may be used together.

  Further, in the above-described embodiment, when the predetermined number of coordinates cannot be acquired within a predetermined time, the procedure for discarding all the coordinates Sp and performing the process from the beginning has been described. However, the old coordinates Sp may be individually excluded, and the plurality of coordinates Sp used for the matching process may be limited to those acquired within a certain time. Moreover, the reference | standard which selects the coordinate Sp utilized for a matching process is not restricted to the time when the coordinate Sp was acquired. For example, in charging / discharging between storage battery units, when the amount of power to be moved exceeds a predetermined amount of power, the old coordinates Sp 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 coordinate Sp is acquired. The reference electric energy may be changed according to the travel distance, the environmental temperature, the accuracy required for the SOC-OCV curve, and the like.

  Next, a method for detecting a failure of the storage battery using the processing until the above SOC-OCV curve is determined will be described. FIG. 9 is a diagram for explaining the concept of failure detection. In FIG. 9, as in FIG. 3, the horizontal axis represents SOC in percent (%), and the vertical axis represents OCV in volts (V).

A plurality of coordinates Sp _n obtained by repeating the storage battery unit mesenchyme discharge, if the normal object storage battery, it should be plotted along approximately the SOC-OCV curve in either the capacity retention rate. However, a fault in the battery as a battery or charging and discharging of the other object in the process of repeating the battery unit mesenchyme discharge occurs, the coordinate values of the subsequently acquired coordinates Sp _x, the abnormality deviating significantly from SOC-OCV curve Can be a value.

FIG. 9 shows a case where the coordinates Sp ₀ are acquired and the coordinates Sp ₁ → Sp ₂ → Sp ₃ → Sp ₄ are acquired in order. To the coordinates Sp3, although are acquired along a curved CL, coordinates Sp ₄ is largely deviated from the curve CL. That is, during the period from the acquisition of the coordinates Sp ₃ to obtain the coordinates Sp _4, suggesting the possibility of failure in the storage battery has occurred. As described above, since the acquired time is associated with each coordinate by the time measuring unit 232, the range of the time when the failure occurs can be limited. Then, it becomes easy to estimate what fault event has occurred by checking the output of another sensor in the limited time range.

More specifically, the determination of the failure is performed by first generating the approximate curve CL by using the coordinates Sp ₀ , Sp ₁ , Sp ₂ , Sp ₃ acquired by the control calculation unit 230 so as to verify the failure. And If the SOC-OCV curve that has already been determined is stored in the determined line holding unit 234, the SOC-OCV curve may be used as the verification curve. Then, the control calculation unit 230 calculates an approximate curve is determined as a verification curve, the distance d between the coordinate Sp ₄ newly acquired. If the distance is greater than a predetermined threshold value d ₀ , control calculation unit 230 determines that coordinate Sp ₄ is an abnormal value and determines that a failure has occurred in the storage battery.

Incidentally, already verification curve generated from a plurality of coordinates Sp _n acquired is not limited to the approximate curve generated using statistical techniques may be simply approximated linearly. The approximate straight line may be a polygonal line connecting the coordinates acquired so far with line segments. The distance d is a deviation with respect to the verification curve, and can be defined by various statistical methods. In the example of FIG. 9, the distance along the OCV axis is d, but the distance from the coordinate Sp ₄ to the foot lowered perpendicularly to the verification curve may be d.

  Next, a failure detection processing flow will be described. FIG. 10 is a flowchart of failure detection. The failure detection processing flow is executed as a sub-function of the processing flow until the SOC-OCV curve described with reference to FIG. 8 is determined. Specifically, the failure detection process S201 is inserted between step S111 and step S112 in FIG.

  When starting the failure detection process S201, the control calculation unit 230 checks in step S212 whether or not the determined SOC-OCV curve of the target storage battery is already stored in the determined line holding unit 234. If stored, the SOC-OCV curve is read from the confirmed line holding unit 234, and is determined as a verification curve in step S213. When the verification curve is determined, the process proceeds to step S215. In the main flow shown in FIG. 8, processing is performed to determine the SOC-OCV curve of the target storage battery, but here it is used for failure detection, so there is some error at the present time. Even past SOC-OCV curves that may be used are used.

Control calculation unit 230, confirm that it is not stored in step S212, the process proceeds to step S214, the generating the verification curve from a plurality of coordinates Sp _n already acquired. When the verification curve is generated, the process proceeds to step S215.

Control calculation unit 230, at step S215, the newly calculates the distance d obtained with Sp _n and the verification curve, the distance d determines whether less than a threshold value d ₀ determined in advance. If it is determined that the battery is small, it is assumed that no failure has occurred in the storage battery and the process returns to the main flow.

On the other hand, if the distance d threshold d ₀ above, the control arithmetic unit 230 determines that a failure to the battery has occurred, at step S216, it transmits a fault signal to the system side. When receiving a failure signal, the control unit on the system side performs failure response promptly by interrupt processing. In this case, the process of determining the SOC-OCV curve in power storage device 100 is interrupted to prioritize failure handling.

  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, 236 Failure Determination Unit

Claims (19)

A first power storage module comprising: a first power storage unit; a first current sensor that detects a current flowing into and out of the first power storage unit; and a first voltage sensor that detects a voltage of the first power storage unit;
A second power storage module comprising a second power storage unit;
A charge / discharge circuit module for charge / discharge between the first power storage unit and the second power storage unit, and a charge / discharge circuit module including a control unit for controlling the charge / discharge circuit;
The controller is
Using the OCV of the first power storage unit before and after the power transfer between the power storage units by charging / discharging between the first power storage unit and the second power storage unit, and the charge / discharge amount of the power transfer, the first power storage A plurality of first coordinates in a two-dimensional plane composed of the SOC and OCV of the first portion, and the first coordinates identified in the step of determining the first correlation information that is the relationship between the SOC and the OCV of the first power storage unit Is characterized by diagnosing a failure state of the first power storage unit when it deviates beyond a predetermined amount from an approximate curve or an approximate line formed by the other first coordinates specified so far. Power storage device.   When the determined first correlation information of the first power storage unit exists, the identified first coordinate deviates beyond a predetermined amount from a straight line or a curve represented by the first correlation information. In this case, the power storage device according to claim 1, wherein the power storage device determines that the first power storage unit has failed. The control unit includes a storage unit that stores in advance the first correlation information in a plurality of deterioration states,
The control unit has at least one coordinate composed 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 in the plurality of deterioration states, and a reference OCV that is an OCV corresponding to the reference SOC. The power storage device according to claim 1 or 2, wherein a plurality of the first coordinates are specified so as to be included.   If the SOC of the first power storage unit before performing the power transfer is not included in the range of the reference SOC, the control unit determines that the SOC of the first power storage unit is equal to the reference SOC before the power transfer. The power storage device according to claim 3, wherein charging and discharging are performed between the first power storage unit and the second power storage unit so as to be included in the range.   When the OCV of the first power storage unit before performing the power transfer is not included in the range of the reference OCV, the control unit determines that the OCV of the first power storage unit is equal to the reference OCV before the power transfer. The power storage device according to claim 3, wherein charging and discharging are performed between the first power storage unit and the second power storage unit so as to be included in the range. The control unit includes a storage unit that stores in advance the first correlation information in a plurality of deterioration states,
The said control part selects the said 1st correlation information memorize | stored in the said memory | storage part from which the deviation with several said 1st coordinate is below a threshold value, and confirms the said 1st correlation information. The power storage device according to any one of claims.   The power storage device according to claim 6, wherein the control unit determines the first correlation information stored in the storage unit having a minimum deviation from a plurality of the first coordinates as the first correlation information.   6. The power storage device according to claim 1, wherein the control unit determines the first correlation information based on an approximate curve or an approximate line formed from a plurality of the first coordinates.   The control unit stores at least one of a charge amount of the first power storage unit when the first coordinates are specified or a time when the first coordinates are specified, and newly sets the first coordinates. When the accumulated amount of the charged amount in the case of specifying exceeds a predetermined threshold value, or the time when the first coordinate is newly specified is a predetermined time from the time of the first coordinate specified previously. The power storage device according to any one of claims 1 to 8, wherein, when exceeding, the first coordinate specified previously is excluded.   The control unit performs the power transfer a plurality of times by switching between discharging from the first power storage unit to the second power storage unit and discharging from the second power storage unit to the first power storage unit. The power storage device according to any one of 1 to 9.   The power storage device according to claim 10, wherein the control unit alternately switches between discharging from the first power storage unit to the second power storage unit and discharging from the second power storage unit to the first power storage unit. 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 said control part controls the said charging / discharging circuit so that a said 1st electrical storage part and a said 2nd electrical storage part may not charge / discharge between the said drive parts, while performing the said electric power transfer. The power storage device according to any one of 11 to 11.   When the control unit receives an inquiry about the SOC of the first power storage unit, the control unit calculates the SOC of the first power storage unit based on the OCV of the first power storage unit and the determined first correlation information. The power storage device according to claim 1, which responds as follows.   The first power storage unit has a larger output weight density that is output power per unit weight than the second power storage unit, and the second power storage unit has an energy weight density that is stored power per unit weight than the first power storage unit. The power storage device according to claim 1, wherein the power storage device is large. The second power storage module includes a second current sensor that detects a current flowing into and out of the second power storage unit, and a second voltage sensor that detects a voltage of the second power storage unit,
The controller is
Using the OCV of the second power storage unit before and after the power transfer and the charge / discharge amount of the power transfer, specifying a plurality of second coordinates in a two-dimensional plane consisting of the SOC and OCV of the second power storage unit, In the step of determining the second correlation information that is the relationship between the SOC and the OCV of the second power storage unit, the specified second coordinate is an approximated curve formed by the other second coordinates specified so far. The power storage device according to claim 14, wherein a failure state of the second power storage unit is diagnosed when deviating from an approximate straight line exceeding a predetermined amount.   A transportation device comprising the power storage device according to claim 1. A first power storage module comprising: a first power storage unit; a first current sensor that detects a current flowing into and out of the first power storage unit; and a first voltage sensor that detects a voltage of the first power storage unit;
A second power storage module comprising a second power storage unit;
A fault diagnosis method in a power storage device comprising: a charge / discharge circuit that performs charge / discharge between the first power storage unit and the second power storage unit; and a charge / discharge circuit module that includes a control unit that controls the charge / discharge circuit. ,
A power transfer step of charging / discharging between the first power storage unit and the second power storage unit;
A plotting step for identifying first coordinates in a two-dimensional plane composed of the SOC and OCV of the first power storage unit based on the OCV of the first power storage unit and the charge / discharge amount in the charge / discharge;
A determination step for determining first correlation information, which is a relationship between the SOC and the OCV of the first power storage unit, based on a plurality of the first coordinates specified by repeating the power transfer step and the plot step a plurality of times;
During the process of the determination step, the identified first coordinate deviates by more than a predetermined amount from the approximate curve or approximate line formed by the other first coordinates identified so far. A failure diagnosis method including a diagnosis step of diagnosing a failure state of the first power storage unit when detected. A first power storage module comprising: a first power storage unit; a first current sensor that detects a current flowing into and out of the first power storage unit; and a first voltage sensor that detects a voltage of the first power storage unit;
A second power storage module comprising a second power storage unit;
A failure diagnosis program for a power storage device, comprising: a charge / discharge circuit that charges and discharges between the first power storage unit and the second power storage unit; and a charge / discharge circuit module that includes a control unit that controls the charge / discharge circuit. ,
A power transfer step of charging / discharging between the first power storage unit and the second power storage unit;
A plotting step for identifying first coordinates in a two-dimensional plane composed of the SOC and OCV of the first power storage unit based on the OCV of the first power storage unit and the charge / discharge amount in the charge / discharge;
A determination step for determining first correlation information, which is a relationship between the SOC and the OCV of the first power storage unit, based on a plurality of the first coordinates specified by repeating the power transfer step and the plot step a plurality of times;
During the process of the determination step, the identified first coordinate deviates by more than a predetermined amount from the approximate curve or approximate line formed by the other first coordinates identified so far. A failure diagnosis program that, when detected, causes a computer to execute a diagnosis step of diagnosing a failure state of the first power storage unit. A first power storage module comprising a first power storage unit;
A second power storage module comprising a second power storage unit;
A charge / discharge circuit module that performs power transfer between power storage units by charging / discharging between the first power storage unit and the second power storage unit,
The charge / discharge circuit module obtains a plurality of first data representing a set of an OCV value and an SOC value in the first power storage unit by repeating the power movement, and based on the obtained plurality of the first data. In the step of determining the first correlation information representing the relationship between the SOC and the OCV of the first power storage unit, the specified first data is a correlation obtained from the other first data specified so far When it is judged that it deviates from, the electrical storage apparatus which estimates the failure of the said 1st electrical storage part.

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