WO2014060810A1 - Système de stockage et procédé de détermination d'anomalie - Google Patents

Système de stockage et procédé de détermination d'anomalie Download PDF

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Publication number
WO2014060810A1
WO2014060810A1 PCT/IB2013/002222 IB2013002222W WO2014060810A1 WO 2014060810 A1 WO2014060810 A1 WO 2014060810A1 IB 2013002222 W IB2013002222 W IB 2013002222W WO 2014060810 A1 WO2014060810 A1 WO 2014060810A1
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WO
WIPO (PCT)
Prior art keywords
storage unit
value
voltage value
current
controller
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Application number
PCT/IB2013/002222
Other languages
English (en)
Inventor
Junichi Hatano
Original Assignee
Toyota Jidosha Kabushiki Kaisha
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Application filed by Toyota Jidosha Kabushiki Kaisha filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2014060810A1 publication Critical patent/WO2014060810A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/392—Determining battery ageing or deterioration, e.g. state of health
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC

Definitions

  • the invention relates to a technique of determining an abnormality condition in a storage unit on the basis of a resistance value of the storage unit.
  • JP-2012-021931 A describes a method of detecting an abnormality in an internal resistance of a battery. More specifically, a relationship between a current value and a voltage value during charging and discharging of a battery is plotted on a coordinate system having the current value and the voltage value as coordinate axes. An approximate straight line (an I-V straight line) is then calculated from a plurality of plot points, whereupon an abnormality in the internal resistance of the battery is detected on the basis of a slope of the approximate straight line.
  • the slope of the approximate straight line becomes sharper as the internal resistance value of the battery increases.
  • a storage system includes: a storage unit configured to be charged and discharged; a voltage sensor configured to detect a voltage value of the storage unit; and a controller configured to determine the storage unit to be in an abnormal condition when a resistance value of the storage unit is higher than a threshold.
  • the controller is configured to specify, when the storage unit is charged or discharged at a constant current, a polarization voltage value corresponding to an energization time on the basis of a correspondence relationship between the energization time and the polarization voltage value.
  • the controller is configured to calculate the resistance value of the storage unit following energization on the basis of the voltage value detected by the voltage sensor, the specified polarization voltage value, an open circuit voltage value of the storage unit following energization, and a current value during energization.
  • the resistance value of the storage unit following energization can be calculated even when the storage unit is charged or discharged under a constant current. More specifically, the resistance value of the storage unit following energization can be calculated using a following Equation (1) ⁇
  • Rc is the resistance value of the storage unit following energization
  • CCV is the voltage value of the storage unit detected by the voltage sensor following energization
  • OCV is the open circuit voltage value of the storage unit following energization
  • Vdyn is a polarization voltage value accompanying energization
  • Ich is the current value during energization (which is a constant value).
  • the polarization voltage value varies in accordance with variation in the current value during energization, but when the storage unit is charged or discharged under a constant current, variation in the current value does not have to be taken into consideration, and therefore the polarization voltage value can be specified more easily.
  • the polarization voltage value corresponding to the energization time can be specified.
  • the polarization voltage value can be estimated more easily than in a case where the polarization voltage value is estimated while the current value varies, and as a result, an estimation precision of the polarization voltage value can be improved.
  • the resistance value of the storage unit following energization is calculated from the polarization voltage value, and therefore, by improving the estimation precision of the polarization voltage value, an estimation precision of the resistance value of the storage unit following energization can also be improved.
  • the above storage system may further include a current sensor configured to detect a current flowing through the storage unit.
  • the above controller may be configured to calculate the open circuit voltage value of the storage unit following energization on the basis of an open circuit voltage value of the storage unit at the start of energization, and an integrated value of the current value detected by the current sensor during energization.
  • the open circuit voltage value of the storage unit following energization can be calculated from the open circuit voltage value of the storage unit at the start of energization and an integrated value of the current value detected by the current sensor during energization.
  • the open circuit voltage value and a state of charge (SOC) of the storage unit have a correspondence relationship, and therefore, by obtaining the open circuit voltage value at the start of energization, the SOC corresponding to the open circuit voltage value can be specified.
  • the SOC of the storage unit following energization can be calculated from the SOC at the start of energization and the integrated current value.
  • the open circuit voltage value corresponding to the SOC following energization can be specified using the correspondence relationship between the open circuit voltage value and the SOC.
  • the controller may be configured to, when the storage unit is charged under a constant current, calculate the resistance value of the storage unit following charging on the basis of power supplied from an external power supply.
  • the storage unit can be charged by supplying power from an external power supply to the storage unit. At this time, the storage unit can be charged at a constant current, and therefore the resistance value of the storage unit can be calculated as described above.
  • the external power supply is a power supply provided separately to the storage system.
  • noise is less likely to be included in the current value flowing through the storage unit.
  • the likelihood of noise being included in the current value of the storage unit may increase in response to driving of the load.
  • the power of the external power supply is supplied to the storage unit, the load is not driven, and therefore the inclusion of noise in the current value of the storage unit can be suppressed.
  • a motor for example, may be used as the load.
  • the above storage system may further include; an inverter configured to convert direct current power output from the storage unit into alternating current power; and a motor configured to convert the alternating current power output from the inverter into kinetic energy for causing a vehicle to travel. More specifically, direct current power output from the storage unit may be converted into alternating current power by an inverter, and the alternating current power may be supplied to the motor. Kinetic energy generated by the motor can then be used as energy for causing a vehicle to travel.
  • the controller may be configured to, when power is supplied to the motor from the storage unit, calculate the resistance value of the storage unit from behavior of the current value and the voltage value of the storage unit.
  • the current value of the storage unit is more likely to vary in accordance with a driving condition of the motor. Therefore, the resistance value of the storage unit can be calculated from behavior of the current value and the voltage value of the storage unit. More specifically, by plotting a relationship between the current value and the voltage value on a coordinate system having the current value and the voltage value as coordinate axes, and specifying a straight line that approximates a plurality of plot points, a slope of the approximate straight line can be set as the resistance value of the storage unit.
  • the controller may be configured to, when the resistance value of the storage unit calculated during charging or discharging of the storage unit at a constant current is higher than a first threshold, determine that the storage unit is in the abnormal condition.
  • the controller may be configured to, when the resistance value of the storage unit calculated while power is supplied from the storage unit to the motor is higher than a second threshold, determine that the storage unit is in the abnormal condition.
  • the first threshold may be lower than the second threshold.
  • the first threshold and the second threshold are set in consideration of an estimation error.
  • the first threshold and the second threshold can be set by adding respective estimation errors to the theoretical threshold.
  • the estimation errors in the resistance value are different from each other, and therefore the estimation error corresponding to the first threshold can be set to be smaller than the estimation error corresponding to the second threshold.
  • the first threshold can be set to be smaller than the second threshold.
  • a second aspect of the invention relates to an abnormality determination method.
  • the abnormality determination method includes; specifying, when a storage unit is charged or discharged at a constant current, a polarization voltage value corresponding to an energization time on the basis of a correspondence relationship between the energization time and the polarization voltage value; calculating a resistance value of the storage unit following energization on the basis of a voltage value of the storage unit detected by a voltage sensor, the specified polarization voltage value, an open circuit voltage value of the storage unit following energization, and a current value during energization; and determining that the storage unit is in an abnormal condition when the calculated resistance value is higher than a threshold.
  • FIG. 1 is a view showing a configuration of a battery system
  • FIG. 2 is a view showing a configuration of a part of the battery system
  • FIG. 3 is a flowchart illustrating processing for determining an abnormality condition of a single cell
  • FIG. 4 is a view showing a relationship between a polarization voltage value and a duration of external charging
  • FIG. 5 is a view illustrating a voltage component included in a voltage detected by a monitoring unit
  • FIG. 6 is a view showing a correspondence relationship between a SOC and an OCV.
  • FIG. 7 is a view showing a relationship between a first threshold and a second threshold.
  • FIG. 1 is a view showing a configuration of a battery system (corresponding to a storage system) according to this embodiment.
  • the battery system shown in FIG. 1 can be installed in a vehicle, for example.
  • the vehicle may be a plug-in hybrid vehicle (PHV) or an electric vehicle (EV). Note that the invention may be applied to an object other than a vehicle.
  • PGV plug-in hybrid vehicle
  • EV electric vehicle
  • a power source such as an internal combustion engine or a fuel cell is provided as a power source for causing the vehicle to travel in addition to a battery pack to be described below.
  • the battery pack can be charged using power from an external power supply.
  • An EV includes only the battery pack as the power source of the vehicle, and the battery pack can be charged by receiving a supply of power from an external power supply.
  • the external power supply is a power supply (a commercial power supply, for example) provided separately to the vehicle on the outward of the vehicle.
  • a battery pack 100 includes a plurality of single cells (corresponding to storage units) 1 connected in series.
  • a secondary battery such as a nickel hydrogen battery or a lithium ion battery may be used as the single cell 1. Further, instead of a secondary battery, an electric double layer capacitor may be used.
  • the number of single cells 1 may be set appropriately on the basis of a required output and so on of the battery pack 100.
  • the battery pack 100 may also include a plurality of single cells 1 connected in parallel.
  • a monitoring unit 201 detects an inter-terminal voltage (closed circuit voltage (CCV)) of the battery pack 100 and a voltage (CCV) of each single cell 1, and outputs detection results to a controller 300.
  • CCV closed circuit voltage
  • the monitoring unit 201 includes voltage monitoring integrated circuits (ICs) 201a in a number corresponding to the number of single cells 1 constituting the battery pack 100, and the voltage monitoring ICs (corresponding to voltage sensors) 201a are connected to the respective single cells 1 in parallel.
  • Each voltage monitoring IC 201a detects the voltage of the corresponding single cell 1, and outputs a detection result to the controller 300.
  • the voltage monitoring IC 201a is provided for each single cell 1, but the invention is not limited thereto.
  • the plurality of single cells 1 constituting the battery pack 100 may be divided into a plurality of battery blocks (corresponding to the storage units), and the voltage monitoring IC 201a may be provided for each battery block.
  • the voltage monitoring ICs 201a may be connected to the respective battery blocks in parallel.
  • the voltage monitoring IC 201a detects a voltage of the corresponding battery block, and outputs a detection result to the controller 300.
  • each battery block is constituted by a plurality of single cells 1 connected in series, and the battery pack 100 is constructed by connecting the plurality of battery blocks in series. Note that a plurality of single cells 1 connected in parallel may be included in each battery block.
  • a current sensor 202 detects a current flowing through the battery pack 100, and outputs a detection result to the controller 300.
  • a positive value may be used as a current value detected by the current sensor 202.
  • a negative value may be used as the current value detected by the current sensor 202.
  • the current sensor 202 is provided on a positive electrode line PL connected to a positive electrode terminal of the battery pack 100, but as long as the current sensor 202 is capable of detecting the current flowing through the battery pack 100, a position in which the current sensor 202 is provided may be set as desired. Note that a plurality of current sensors 202 may be used.
  • the controller 300 includes a memory 301, and the memory 301 stores various information required for the controller 300 to perform predetermined processing (processing described in this embodiment, for example).
  • the controller 300 also includes a timer 302, and the timer 302 is used to measure time.
  • the memory 301 and the timer 302 are built into the controller 300, but at least one of the memory 301 and the timer 302 may be provided on the outward of the controller 300.
  • a system main relay SMR-B is provided on the positive electrode line PL connected to the positive electrode terminal of the battery pack 100.
  • the system main relay SMR-B is switched ON and OFF upon reception of a control signal from the controller 300.
  • a system main relay SMR-G is provided on a negative electrode line NL connected to a negative electrode terminal of the battery pack 100.
  • the system main relay SMR-G is switched ON and OFF upon reception of a control signal from the controller 300.
  • a system main relay SMR-P and a current limiting resistor 203 are connected in parallel to the system main relay SMR-G.
  • the system main relay SMR-P and the current limiting resistor 203 are connected in series.
  • the system main relay SMR-P is switched ON and OFF upon reception of a control signal from the controller 300.
  • the current limiting resistor 203 is used to suppress a flow of an inrush current when the battery pack 100 is connected to a load (more specifically, an inverter 204 to be described below).
  • the battery pack 100 is connected to the inverter 204 via the positive electrode line PL and the negative electrode line NL.
  • the controller 300 first switches the system main relay SMR-B from OFF to ON and switches the system main relay SMR-P from OFF to ON. As a result, a current flows through the current limiting resistor 203.
  • the controller 300 switches the system main relay SMR-G from OFF to ON, and then switches the system main relay SMR-P from ON to OFF.
  • a connection between the battery pack 100 and the inverter 204 is completed, whereby the battery system shown in FIG. 1 enters an activated condition (Ready-On).
  • Information relating to an ON/OFF condition of an ignition switch of the vehicle is input into the controller 300, and when the ignition switch is switched from OFF to ON, the controller 300 activates the battery system.
  • the controller 300 switches the system main relays SMR-B, SMR-G from ON to OFF.
  • the connection between the battery pack 100 and the inverter 204 is interrupted, whereby the battery system enters a stopped condition (Ready-Off).
  • the inverter 204 converts direct current power output by the battery pack 100 into alternating current power, and outputs the alternating current power to a motor/generator 205.
  • a three-phase alternating current motor for example, may be used as the motor/generator 205.
  • the motor/generator 205 receives the alternating current power output by the inverter 204, and generates kinetic energy for causing the vehicle to travel. The kinetic energy generated by the motor/generator 205 is transmitted to a vehicle wheel, enabling the vehicle to travel.
  • the motor/generator 205 converts kinetic energy generated during braking of the vehicle into electric energy (alternating current power).
  • the inverter 204 converts the alternating current power generated by the motor/generator 205 into direct current power, and outputs the direct current power to the battery pack 100.
  • the battery pack 100 can store regenerative power.
  • the battery pack 100 is connected to the inverter 204, but the invention is not limited thereto. More specifically, the battery pack 100 may be connected to a booster circuit, and the booster circuit may be connected to the inverter 204. By employing a booster circuit, an output voltage of the battery pack 100 can be boosted. Further, the booster circuit can reduce the output voltage output from the inverter 204 to the battery pack 100.
  • a charger 206 is connected to the positive electrode line PL and the negative electrode line NL. More specifically, the charger 206 is connected to the positive electrode line PL connecting the system main relay SMR-B to the inverter 204, and the negative electrode line NL connecting the system main relay SMR-G to the inverter 204.
  • An inlet (a connector) 207 is connected to the charger 206.
  • Charging relays Rchl, Rch2 are provided on lines respectively connecting the lines PL, NL to the charger 206.
  • the charging relays Rchl, Rch2 are switched ON and OFF upon reception of a control signal from the controller 300.
  • a plug (a connector) connected to an external power supply is connected to the inlet 207.
  • power from the external power supply can be supplied to the battery pack 100 via the charger 206.
  • the battery pack 100 can be charged using an external power supply. Charging of the battery pack 100 using the external power supply will be referred to as external charging.
  • the charger 206 converts the alternating current power from the external power supply into direct current power, and supplies the direct current power to the battery pack 100.
  • the controller 300 is capable of controlling an operation of the charger 206.
  • the charger 206 is also capable of converting a voltage during external charging.
  • a system for supplying power from the external power supply to the battery pack 100 is not limited to the system shown in FIG. 1.
  • the charger 206 may be connected to the battery pack 100 without passing through the system main relays SMR-B, SMR-P, SMR-G. More specifically, the charger 206 may be connected to the positive electrode line PL connecting the battery pack 100 to the system main relay SMR-B and the negative electrode line NL connecting the battery pack 100 to the system main relay SMR-G via the charging relays Rchl, Rch2.
  • external charging can be performed by switching the charging relays Rchl, Rch2 from OFF to ON.
  • external charging is performed by connecting the plug to the inlet 207, but the invention is not limited thereto. More specifically, the power of the external power supply can be supplied to the battery pack 100 using a so-called non-contact charging system.
  • a non-contact charging system power can be supplied without passing through a cable using electromagnetic induction or a resonance phenomenon.
  • a conventional configuration may be employed appropriately as the non-contact charging system.
  • the charger 206 is installed in the vehicle, but the invention is not limited thereto, and the charger 206 may be provided separately to the vehicle on the outward of the vehicle. In this case, direct current power is supplied to the battery system shown in FIG. 1 from the outward of the vehicle. Further, the controller 300 may control the operation of the charger 206 through communication between the controller 300 and the charger 206.
  • the single cell 1 As deterioration of the single cell 1 advances, a resistance value of the single cell 1 increases, and therefore a deterioration condition of the single cell 1 can be learned by calculating (estimating) the resistance value of the single cell 1. Further, the single cell 1 can be determined to be in an abnormal condition according to the deterioration condition of the single cell 1.
  • the resistance value of the single cell 1 is calculated, and the abnormality condition of the single cell 1 (the battery pack 100) is determined on the basis of the calculated resistance value.
  • the invention is not limited thereto. More specifically, the resistance value of the battery pack 100 or the aforementioned battery block may be calculated, and the abnormality condition of the battery pack 100 or the battery block may be determined on the basis of the calculated resistance value.
  • the battery pack 100 or the battery block may be regarded as the storage unit according to the invention.
  • step S101 the controller 300 determines whether or not external charging is underway.
  • external charging can be started by connecting the plug to the inlet 207, and therefore the controller 300 determines whether or not external charging is underway by determining whether or not the plug is connected to the inlet 207.
  • the controller 300 determines whether or not external charging is underway by communicating with a power supply side system.
  • the battery pack 100 can be set in a fully charged condition, for example.
  • a voltage value of the battery pack 100 increases.
  • the battery pack 100 the single cell 1 enters the fully charged condition.
  • step S102 the controller 300 estimates a polarization voltage value of the single cell 1 upon completion of the external charging.
  • the polarization voltage value is a voltage variation amount accompanying polarization during charging of the single cell 1.
  • the polarization voltage value can be estimated.
  • the ordinate shows the polarization voltage value
  • the abscissa shows a duration of the external charging (an energization time).
  • a relationship between the polarization voltage value and the duration of the external charging may be determined using the current value during external charging (which is a constant value) as a reference.
  • the polarization voltage value also varies according to the current value flowing through the battery pack 100, but when external charging is performed, a specific current value alone flows continuously, and therefore the map shown in FIG. 4 may be created using the current value at this time as a reference.
  • Variation in the current value need not be taken into account when estimating the polarization voltage value following external charging, and therefore the polarization voltage value can be estimated precisely simply by taking into account the duration of the external charging.
  • the polarization voltage value must be estimated while also taking into consideration the variation in the current value, and as a result, it becomes more difficult to estimate the polarization voltage value.
  • the variation in the current value does not have to be taken into account, and therefore the polarization voltage value can be estimated easily.
  • an estimation precision of the polarization voltage value can be improved in comparison with a case where the polarization voltage value is estimated while also taking into account the variation in the current value.
  • the map shown in FIG. 4 can be stored in the memory 301 in advance.
  • the controller 300 by measuring a time (a duration) following the start of external charging, can specify a polarization voltage value corresponding to the measured time from the map shown in FIG. 4.
  • the time following the start of external charging can be measured using the timer 302.
  • the controller 300 estimates a resistance value Rc of the single cell 1. More specifically, the controller 300 can calculate the resistance value Rc of the single cell 1 on the basis of a following Equation (1). In this embodiment, the resistance value Rc of the single cell 1 is calculated, but a resistance value of the battery pack 100 or a resistance value of the aforementioned battery block may be calculated instead. In these cases, the resistance value of the battery pack 100 or the battery block can be calculated using a similar method to the method of calculating the resistance value Rc of the single cell 1.
  • Equation (1) the CCV is the voltage value of the single cell 1 detected by the monitoring unit 201, and open circuit voltage (OCV) is an open circuit voltage value of the single cell 1.
  • CCV and OCV denote the CCV and the OCV of the single cell 1 following the completion of external charging.
  • Vdyn is the polarization voltage value estimated in the processing of step S102.
  • Ich is the current value during charging of the battery pack 100 (the single cell 1). During external charging, the current value Ich is substantially constant.
  • the voltage value (CCV) of the single cell 1 detected by the monitoring unit 201 includes the OCV of the single cell 1, a voltage increase corresponding to the internal resistance (the resistance value Rc) of the single cell 1, and the polarization voltage value. Equation (1) can be derived from the relationship shown in FIG. 5.
  • the OCV of the single cell 1 following the completion of external charging can be calculated on the basis of the voltage (OCV) of the single cell 1 at the start of external charging and an integrated current value obtained during external charging.
  • OCV voltage
  • a method of calculating the OCV of the single cell 1 following the completion of external charging will be described below.
  • the OCV of the single cell 1 can be measured using the monitoring unit 201.
  • the OCV of the single cell 1 can be measured by passing a weak current through the single cell 1 in a condition where the battery pack 100 is not connected to the load (the inverter 204).
  • the inverter 204 By passing a weak current through the single cell 1, voltage variation corresponding to the internal resistance of the single cell 1 can be ignored, and the voltage of the single cell 1 detected by the monitoring unit 201 may be considered as the OCV of the single cell 1.
  • a SOC corresponding to the OCV can be specified.
  • the SOC is a ratio between a current charged capacity and a fully charged capacity.
  • the OCV and the SOC have a correspondence relationship, and therefore, by determining this correspondence relationship in advance through experiment or the like, the SOC corresponding to the OCV can be specified.
  • the SOC following the completion of external charging can be calculated by integrating the current value detected by the current sensor 202 while external charging is underway.
  • the SOC following the completion of external charging can be calculated on the basis of the SOC at the start of external charging and the integrated current value obtained while external charging is underway.
  • the OCV corresponding to the calculated SOC can be specified on the basis of the correspondence relationship between the SOC and the OCV, shown in FIG. 6. As a result, the OCV of the single cell 1 following the completion of external charging can be calculated.
  • the resistance value Rc of the single cell 1 following the completion of external charging is calculated, but the invention is not limited thereto, and the resistance value Rc of the single cell 1 may also be calculated while external charging is underway using Equation (1).
  • the CCV and the OCV at a specific timing during external charging can be used as the CCV and the OCV of Equation (1).
  • a polarization voltage value corresponding to a duration up to the specific timing can be used as Vdyn.
  • step S104 the controller 300 determines whether or not the resistance value Rc calculated in the processing of step S103 is higher than a first threshold Rthl.
  • the first threshold Rthl is a threshold for determining whether or not the single cell 1 is in an abnormal condition, and may be set as desired. Information relating to the first threshold Rthl can be stored in the memory 301 in advance.
  • the highest resistance value Rc can be compared with the first threshold Rthl. In so doing, a determination as to whether or not the resistance value Rc is lower than the first threshold Rthl can be made in relation to all of the single cells 1 constituting the battery pack 100.
  • the first threshold Rthl should be set in accordance with this resistance value.
  • the highest resistance value can be compared to the first threshold Rthl. In so doing, the determination as to whether or not the resistance value is lower than the first threshold Rthl can be made in relation to all of the battery blocks.
  • step S105 the controller 300 determines that the single cell 1 is in an abnormal condition.
  • the single cell 1 is determined to be in an abnormal condition
  • the battery block is determined to be in an abnormal condition on the basis of the resistance value of the battery block, this means that the battery pack 100 includes the battery block in an abnormal condition, and therefore the controller 300 determines that the battery pack 100 is in an abnormal condition.
  • the controller 300 can provide a user or the like with information relating to the abnormal condition.
  • a sound or a display may be used as notifying means.
  • the controller 300 can output information indicating that the battery pack 100 is in an abnormal condition.
  • the controller 300 can display information indicating that the battery pack 100 is in an abnormal condition.
  • the controller 300 can limit input/output (charging/discharging) to and from the battery pack 100.
  • upper limit values at which input/output to and from the battery pack 100 is permitted can be reduced.
  • Upper limit values are set respectively for input into (charging of) and output from (discharging of) the battery pack 100.
  • charging/discharging of the battery pack 100 is controlled such that power used during charging/discharging of the battery pack 100 does not exceed an upper limit value, and therefore, by reducing the upper limit values, charging/discharging of the battery pack 100 can be limited.
  • reducing the upper limit values includes setting the upper limit values at 0 [kW]. By setting the upper limit value corresponding to input at 0 [kW], charging of the battery pack 100 can be stopped. Further, by setting the upper limit value corresponding to output at 0 [kW], discharging of the battery pack 100 can be stopped.
  • step S106 the controller 300 determines whether or not an SN ratio is smaller than a threshold.
  • the threshold is a threshold for determining whether or not noise included in the current value flowing through the battery pack 100, when such noise is included in the current value, is allowable. Information relating to the threshold may be stored in the memory 301.
  • the controller 300 can calculate the resistance value of the single cell 1 on the basis of the current value and the voltage value of the single cell 1. More specifically, a relationship between the detected current and voltage values is plotted on a coordinate system having the current value and the voltage value as respective coordinate axes. A straight line approximating a plurality of plot points is then calculated, and a slope of the approximate straight line indicates the resistance value of the single cell 1. When the vehicle is traveling, the current value varies is more likely to vary, and therefore the approximate straight line can be obtained.
  • the current value of the single cell 1 when noise is included in the current value of the single cell 1, the current value varies in accordance with a magnitude of the noise. As the noise increases, the detected current value becomes steadily more likely to deviate from a true current value.
  • the resistance value of the single cell 1 is calculated in this condition, the calculated resistance value deviates from a true resistance value, making it difficult to grasp the deterioration condition of the single cell 1.
  • the threshold is set, and the resistance value of the single cell 1 is calculated only when the SN ratio is smaller than the threshold.
  • the controller 300 terminates the processing shown in FIG. 3. In other words, when the SN ratio is larger than the threshold, the controller 300 does not calculate the resistance value Rc of the single cell 1. When the SN ratio is smaller than the threshold, on the other hand, the controller 300 performs processing of step S107.
  • step S107 the controller 300 estimates the resistance value Rc of the single cell 1. More specifically, as described above, the controller 300 can specify the resistance value Rc of the single cell 1 by plotting the relationship between the detected current and voltage values and calculating the slope of the approximate straight line.
  • the current value of the single cell 1 can be detected using the current sensor 202, and the voltage value of the single cell I can be detected using the monitoring unit 201.
  • step S108 the controller 300 determines whether or not the resistance value Rc calculated in the processing of step S107 is higher than a second threshold Rth2.
  • the second threshold Rth2 is a threshold for determining whether or not the single cell 1 is in an abnormal condition, and takes a value corresponding to the first threshold Rthl described above.
  • Information relating to the second threshold Rth2 can be stored in the memory 301 in advance.
  • the first threshold Rthl is lower than the second threshold Rth2.
  • a threshold Rlim for determining whether or not the single cell 1 is in an abnormal condition is set.
  • the threshold Rlim is a theoretical value.
  • the first threshold Rthl and the second threshold Rth2 are then set using the threshold Rlim as a reference.
  • the second threshold Rth2 is set in consideration of an estimation error AR2 in the resistance value. In other words, a value obtained by adding the estimation error AR2 to the threshold Rlim is set as the second threshold Rth2. Further, the first threshold Rthl is set in consideration of an estimation error ARl in the resistance value. In other words, a value obtained by adding the estimation error ARl to the threshold Rlim is set as the first threshold Rthl.
  • noise is more likely to be included in the current value detected by the current sensor 202.
  • noise generated by switching the inverter 204 may be included in the current value, and a ripple current may be generated when the motor/generator 205 is driven. Noise is particularly likely to affect the current value when the motor/generator 205 is driven.
  • the estimation precision of the resistance value Rc calculated when external charging is underway is higher than the estimation precision of the resistance value Rc calculated when external charging is not underway, or in other words when the vehicle is traveling.
  • the estimation error ARl can be set to be smaller than the estimation error AR2.
  • estimation error AR2 If the estimation error AR2 is reduced in a situation where noise is likely to be included in the current value, the likelihood of determining erroneously that the single cell 1 is in an abnormal condition increases. When the vehicle is traveling, therefore, it is necessary to increase the estimation error AR2 by an amount corresponding to the likelihood that noise is included in the current value.
  • the estimation precision of the resistance value Rc can be improved, and therefore the estimation error ARl can be set to be smaller than the estimation error AR2.
  • the estimation error ARl can be set to be smaller than the estimation error AR2
  • the abnormality condition of the single cell 1 can be determined earlier.
  • the single cell 1 When the resistance value Rc is higher than the second threshold Rth2 during vehicle travel, the single cell 1 is determined to be in an abnormal condition.
  • the single cell 1 can also be determined to be in an abnormal condition when the resistance value Rc estimated during external charging is higher than the first threshold Rthl but has not yet reached the second threshold Rth2. It is therefore possible to determine the abnormality condition of the single cell 1 earlier when external charging is underway than when the vehicle is traveling.
  • the resistance value Rc of the single cell 1 can be estimated not only when the vehicle is traveling, but also when external charging is underway. As a result, opportunities for estimating the resistance value Rc of the single cell 1 can be increased, and therefore the current resistance value Rc of the single cell 1 can be grasped more easily.
  • the resistance value Rc is not estimated, and therefore an opportunity for calculating the resistance value Rc is lost.
  • a frequency with which the resistance value Rc is calculated can be increased.
  • the resistance value Rc is calculated when external charging is underway, or in other words when the battery pack 100 is charged under a constant current, but the invention is not limited thereto. More specifically, the resistance value Rc may be calculated likewise when the battery pack 100 is discharged under a constant current.
  • the battery pack 100 can be connected to a device (an external device) provided on the outward of the vehicle so that the power of the battery pack 100 is supplied to the external device.
  • a device an external device
  • the power of the battery pack 100 may be supplied to an accessory installed in the vehicle under a constant current. In such cases, the battery pack 100 is discharged under a constant current.
  • the resistance value Rc of the single cell 1 can be calculated using Equation (1).
  • the battery pack 100 is discharged under a constant current, and therefore, by determining a relationship (a relationship corresponding to FIG. 4) between the polarization voltage value and a discharge duration (the energization time) in advance through experiment or the like, a polarization voltage value corresponding to the discharge duration can be specified.
  • Noise inclusion in the current value can be suppressed likewise when the battery pack 100 is discharged under a constant current, and therefore the estimation precision of the resistance value Rc can be improved in a similar manner to this embodiment.
  • the resistance value Rc By calculating the resistance value Rc during discharge at a constant current as well as during vehicle travel and external charging, opportunities for calculating the resistance value Rc can be increased, and as a result, the current resistance value Rc of the single cell 1 can be grasped more easily.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Secondary Cells (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Tests Of Electric Status Of Batteries (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

La présente invention se rapporte à un système de stockage qui comprend : une unité de stockage (1, 100) qui est chargée et déchargée ; un capteur de tension (201) qui détecte une valeur de tension de l'unité de stockage ; et un dispositif de commande (300) qui détermine si l'unité de stockage est dans une condition anormale lorsqu'une valeur de résistance de l'unité de stockage est supérieure à un seuil. Lorsque l'unité de stockage est chargée ou déchargée à un courant constant, le dispositif de commande spécifie d'abord une valeur de tension de polarisation qui correspond à un temps d'excitation à l'aide d'une relation de correspondance entre le temps d'excitation et la valeur de tension de polarisation. Le dispositif de commande calcule ensuite la valeur de résistance de l'unité de stockage après l'excitation à l'aide de la valeur de tension détectée par le capteur de tension, la valeur de tension de polarisation spécifiée et une valeur de tension de circuit ouvert de l'unité de stockage après excitation, et une valeur de courant pendant l'excitation.
PCT/IB2013/002222 2012-10-19 2013-10-08 Système de stockage et procédé de détermination d'anomalie WO2014060810A1 (fr)

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JP2012231454A JP2014085118A (ja) 2012-10-19 2012-10-19 蓄電システムおよび異常判別方法

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5672951A (en) * 1994-11-04 1997-09-30 Mitsubishi Denki Kabushiki Kaisha Determination and control of battery state
US20060273763A1 (en) * 2003-03-31 2006-12-07 Yazaki Corporation Battery status monitoring apparatus and method
US20080157777A1 (en) * 2006-12-27 2008-07-03 Panasonic Ev Energy Co., Ltd. Electromotive force computing device and state of charge estimating device
GB2461350A (en) * 2007-12-27 2010-01-06 Hitachi Ltd Battery deterioration determination based on internal resistances per temperature range
US20110156713A1 (en) * 2009-12-25 2011-06-30 Primearth Ev Energy Co., Ltd. Apparatus for calculating polarization voltage of secondary battery and apparatus for estimating state of charge of the same
JP2012021931A (ja) 2010-07-16 2012-02-02 Toyota Motor Corp 組電池の異常検出装置

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5092218B2 (ja) * 2005-09-06 2012-12-05 富士通株式会社 電池パックの異常検出方法、電池パック及び電子機器
JP5393182B2 (ja) * 2009-01-31 2014-01-22 カルソニックカンセイ株式会社 バッテリの内部抵抗成分推定方法及び充電容量推定方法
JP5566926B2 (ja) * 2011-02-25 2014-08-06 古河電気工業株式会社 二次電池状態検出装置および二次電池状態検出方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5672951A (en) * 1994-11-04 1997-09-30 Mitsubishi Denki Kabushiki Kaisha Determination and control of battery state
US20060273763A1 (en) * 2003-03-31 2006-12-07 Yazaki Corporation Battery status monitoring apparatus and method
US20080157777A1 (en) * 2006-12-27 2008-07-03 Panasonic Ev Energy Co., Ltd. Electromotive force computing device and state of charge estimating device
GB2461350A (en) * 2007-12-27 2010-01-06 Hitachi Ltd Battery deterioration determination based on internal resistances per temperature range
US20110156713A1 (en) * 2009-12-25 2011-06-30 Primearth Ev Energy Co., Ltd. Apparatus for calculating polarization voltage of secondary battery and apparatus for estimating state of charge of the same
JP2012021931A (ja) 2010-07-16 2012-02-02 Toyota Motor Corp 組電池の異常検出装置

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