JP2010252566A - Charge/discharge control circuit and power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge/discharge control circuit for reducing a rush current generated when a secondary battery once separated from a parallel circuit of the secondary battery is connected in parallel again. <P>SOLUTION: The charge/discharge control circuit includes: a cut-off release part 54 for turning on a switching part connected in series to a curt-off target battery of which the abnormality is solved when a difference voltage Vd between a cut-off battery voltage Verr which is a terminal voltage of the cut-off target battery of which the abnormality is solved, and a connection battery voltage Vn which is the terminal voltage of the secondary battery except the cut-off target battery is less than a voltage difference threshold Von; and a cut-off release preparation part 55 for executing preparation treatment by which the switching part connected in series to the cut-off target battery of which the abnormality is solved is tuned on/off in a pulse shape when the abnormality of the cut-off target battery is solved and the difference between the cut-off battery voltage Verr and the connection battery voltage Vn exceeds the voltage difference threshold Von. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charge / discharge control circuit for controlling charge / discharge of a secondary battery, and a power supply device using the same.

  In recent years, power storage devices using secondary batteries have been widely used as power supply systems in combination with solar cells and power generation devices. The power generation device is driven by natural energy such as wind power or hydraulic power or artificial power such as an internal combustion engine. A power supply system that combines such power storage devices is designed to improve energy efficiency by storing surplus power in the power storage device and supplying power from the power storage device when a load device is required.

  An example of such a system is a solar power generation system. The solar power generation system charges the power storage device with surplus power when the amount of power generated by sunlight is larger than the power consumption of the load device. On the contrary, when the power generation amount is smaller than the power consumption of the load device, the load device is driven by outputting from the power storage device in order to compensate for the insufficient power.

  Thus, in the photovoltaic power generation system, surplus power that has not been used in the past can be stored in the power storage device, so that energy efficiency can be improved compared to a power supply system that does not use the power storage device.

  In such a power supply system, when the power storage device is fully charged, surplus power cannot be charged and a loss occurs. Therefore, in order to efficiently charge the power storage device with surplus power, charge control is performed so that the state of charge of the secondary battery (hereinafter referred to as SOC: State Of Charge) does not become 100%. In addition, charging control is performed so that the SOC does not become 0 (zero)% so that the load device can be driven when necessary. Specifically, in the power storage device, charging control is normally performed so that the SOC changes in the range of 20% to 80%.

  A hybrid electric vehicle (HEV) using an engine and a motor also uses such a principle. When the output from the engine is large relative to the power required for traveling, the HEV drives the generator with the surplus engine output and charges the power storage device. In addition, the HEV charges the power storage device by using the motor as a generator during braking or deceleration of the vehicle.

  In addition, load leveling power sources and plug-in hybrid vehicles that are used to effectively use nighttime power have recently attracted attention.

  The load leveling power source is a system that stores power in a power storage device at night when the power consumption is low and the power rate is low, and uses the stored power during the day when the power consumption peaks. The purpose is to make the power generation amount constant by smoothing the power consumption, and to contribute to the efficient operation of power facilities and the reduction of capital investment.

Plug-in hybrid vehicles use electric power at night, mainly EV driving to supply power from the power storage device when driving in urban areas with poor fuel efficiency, and by HEV driving using the engine and motor during long distance driving, The aim is to reduce the total CO ₂ emissions.

  By the way, a power storage device mounted on a power supply device is configured by connecting a plurality of secondary batteries (single cells or the like) in series or in parallel in order to obtain a predetermined output voltage and capacity. Thus, in a power storage device in which a plurality of secondary batteries are connected in parallel, when abnormality or deterioration of the secondary battery is detected, it is necessary to disconnect the secondary battery in which the abnormality or deterioration has occurred from the power storage device.

  In addition, in a power storage device in which a plurality of secondary batteries are connected in parallel, there are variations in the state of abnormality or deterioration of the secondary battery among the elements, so that deterioration is progressing or abnormal. When the abnormality is resolved, the control is performed so that the disconnected secondary battery is connected again (see, for example, Patent Document 1).

  However, when a secondary battery once disconnected is connected in parallel to another secondary battery again, if the difference in terminal voltage between the secondary battery and the other secondary battery is large, the secondary battery will be instantly connected in parallel. There is an inconvenience that an inrush current flows through the secondary battery to deteriorate the secondary battery, or the voltage supplied from these secondary batteries to the load fluctuates.

  Therefore, in Patent Document 1, before the secondary battery once disconnected is connected in parallel with another secondary battery again, it is connected to the other secondary battery via a current limiting resistor to thereby reduce the inrush current. While limiting, the terminal voltage difference with other secondary batteries is eliminated, and then the disconnected secondary battery is connected in parallel with other secondary batteries to reduce inrush current. .

JP 2007-259612 A

  However, in the configuration described in Patent Document 1, in order to reduce the inrush current that may occur when the secondary battery that has been once disconnected is connected in parallel with another secondary battery, Therefore, a switching element or the like for opening and closing the connection of the resistor is required, which causes inconveniences that increase the cost and increase the size of the apparatus.

  An object of the present invention is to provide a current limiting resistor in order to reduce an inrush current that may occur when a secondary battery that has been once disconnected is connected in parallel again from a parallel circuit in which a plurality of secondary batteries are connected in parallel. It is an object of the present invention to provide a charge / discharge control circuit and a power supply device that can reduce such an inrush current without using a power source.

  A charge / discharge control circuit according to the present invention includes a plurality of secondary batteries connected in parallel and a plurality of switching units each connected in series, a terminal voltage detection unit that detects a terminal voltage of each of the secondary batteries, An abnormality determination unit that determines whether or not each secondary battery is abnormal, and a secondary battery that is determined to be abnormal when any of the secondary batteries is determined to be abnormal by the abnormality determination unit. A separation control unit that turns off a switching unit connected in series with the separation target battery, an abnormality elimination determination unit that determines whether or not the abnormality of the separation target battery has been eliminated, and the abnormality elimination It is determined that the abnormality of the separation target battery has been resolved by the determination unit, and is the terminal voltage detected by the terminal voltage detection unit in the separation target battery in which the abnormality has been resolved. If the difference between the disconnected battery voltage and the connected battery voltage, which is the terminal voltage detected by the terminal voltage detection unit in the secondary battery other than the separation target battery, is less than the preset voltage difference threshold, the abnormality The disconnection release unit that turns on the switching unit connected in series with the separation target battery that has been resolved, and the abnormality elimination determination unit determines that the abnormality of the separation target battery has been resolved, and the separation battery voltage and the connection battery voltage A separation release preparation unit that executes a preparation process for turning on and off the switching unit connected in series with the separation target battery in which the abnormality has been eliminated when the difference exceeds the voltage difference threshold value.

  According to this configuration, a plurality of series circuits of the switching unit and the secondary battery are connected in parallel, and each secondary battery can be individually disconnected from or connected to another secondary battery by each switching unit. . If any of the secondary batteries has an abnormality, the separation control unit turns the abnormality secondary battery into a separation target battery, and turns off the switching unit connected in series with the separation target battery. Disconnected.

  Then, when the abnormality of the separation target battery is resolved, the difference between the separation battery voltage that is the terminal voltage of the separation target battery in which the abnormality is resolved and the connection battery voltage that is the terminal voltage of the secondary battery other than the separation target battery. However, when it is considered that a large inrush current does not flow even when the separation target battery is connected to another secondary battery because it is a small value that does not satisfy the preset voltage difference threshold, the separation release unit Since the switching unit connected in series with the separation target battery is turned on, inrush current due to the voltage difference can be reduced without using a current limiting resistor.

  Further, when the abnormality of the separation target battery is resolved, the voltage difference between the separation battery voltage and the terminal voltage of the other secondary battery is a large value that exceeds the voltage difference threshold value. If there is a possibility that a large inrush current will flow and inconvenience may occur if the secondary battery is connected as it is, the switching unit connected in series with the separation target battery whose abnormality has been resolved is turned on and off in pulses by the separation release preparation unit Is done. Thereby, the time average amount of the current flowing through the separation target battery due to the voltage difference is reduced, and the discharge current or the charging current of the separation target battery flows little by little in the direction of decreasing the voltage difference. And, when this voltage difference falls below the voltage difference threshold, the switching unit connected in series with the separation target battery is turned on by the separation release unit and the separation is released, so without using a current limiting resistor, Inrush current due to the voltage difference can be reduced.

  A storage charge amount detection unit that detects a storage charge amount of the plurality of secondary batteries; and a remaining charge that excludes the separation target battery based on the storage charge amount of each secondary battery detected by the storage charge amount detection unit. A remaining storage amount acquisition unit that acquires the total amount of stored charge of the secondary battery as a remaining storage amount, and the abnormality elimination determination unit determines that the abnormality of the separation target battery has been resolved, and the separation battery voltage and the In the case where the difference from the connected battery voltage exceeds the voltage difference threshold, when the remaining power storage amount acquired by the remaining power storage amount acquisition unit exceeds a preset power storage amount threshold, the preparation by the disconnection release preparation unit Permitting processing, and when the remaining power storage amount acquired by the remaining power storage amount acquisition unit is less than the power storage amount threshold, the preparation processing by the disconnection release preparation unit is prohibited and the abnormality It is preferable to further comprising a residual electricity quantity management unit to turn off the disconnecting target cell connected in series with a switching unit which solves.

  According to this configuration, the remaining storage amount acquisition unit acquires the total stored charge amount of the remaining secondary batteries excluding the separation target battery, that is, the stored charge amount that can be discharged to the outside as the remaining storage amount. . Further, when the remaining power storage amount exceeds a preset power storage amount threshold value, that is, when there is a margin in the remaining power storage amount, the remaining power storage amount management unit permits the preparation processing by the disconnection release preparation unit. On the other hand, when the remaining power storage amount is less than the power storage amount threshold value, the remaining power storage amount management unit prohibits the preparation process by the disconnection release preparation unit and turns off the switching unit connected in series with the separation target battery in which the abnormality has been resolved. Is done.

  Here, when the preparatory process by the separation release preparation unit is executed, there is a possibility that the amount of stored charge that can be discharged to the outside further decreases due to the current flowing from the secondary battery other than the separation target battery to the separation target battery. . Therefore, if the remaining power storage amount is less than the power storage amount threshold and the preparatory process is performed by the disconnection release preparation unit, there is a risk that the amount of stored charge that can be discharged to the outside is insufficient with respect to the required amount. is there. However, when the remaining power storage amount is less than the power storage amount threshold, the remaining power storage amount management unit prohibits the preparatory processing by the disconnection release preparation unit, and current flows from the secondary battery other than the separation target battery to the separation target battery. Therefore, the possibility that the amount of stored charge that can be discharged to the outside is insufficient can be reduced.

  Each of the switching units is a series of a charging switching element that prohibits charging of each of the secondary batteries and a discharging switching element that prohibits discharging, and the disconnection release preparation unit includes: When the separation battery voltage is higher than the connection battery voltage as the preparation process, the discharge switching element connected in series with the separation target battery is turned on and off in a pulsed manner, and the separation battery voltage is lower than the connection battery voltage It is preferable that the charging switching element connected in series with the separation target battery is turned on and off in a pulsed manner.

  According to this configuration, the charging current and the discharging current of each secondary battery can be individually prohibited by the charging switching element and the discharging switching element. When the separation battery voltage is higher than the connection battery voltage and the separation target battery is discharged when the separation target battery is connected to another secondary battery, the separation release preparation unit performs serial connection with the separation target battery as a preparation process. The discharged switching element is turned on and off in pulses, and the time average amount of the discharge current of the battery to be disconnected is reduced. As a result, the voltage difference between the separation target battery and the other secondary battery can be reduced while reducing the inrush current.

  When the separation battery voltage is lower than the connection battery voltage and the separation target battery is charged when the separation target battery is connected to another secondary battery, the separation release preparation unit performs serial processing with the separation target battery as a preparation process. Since the connected charging switching element is turned on and off in a pulsed manner, the time average amount of charging current of the separation target battery is reduced, so that the voltage between the separation target battery and another secondary battery is reduced while reducing the inrush current. The difference can be reduced.

  In addition, in the preparation process, when the separation battery voltage is higher than the connection battery voltage, the separation release preparation unit turns off the charging switching element connected in series with the separation target battery in which the abnormality is resolved, When the separation battery voltage is lower than the connection battery voltage, it is preferable to turn off the discharge switching element connected in series with the separation target battery.

  According to this configuration, in the preparation process, when the separation battery voltage is higher than the connection battery voltage and it is desired to reduce the voltage difference between the separation target battery and another secondary battery by discharging the separation target battery, the separation battery is disconnected. The release preparation unit turns off the charging switching element connected in series with the separation target battery, and prevents the increase in the potential difference due to the separation target battery being charged.

  And, in the preparation process, when the separation battery voltage is lower than the connection battery voltage and it is desired to reduce the voltage difference between the separation target battery and the other secondary battery by charging the separation target battery, the separation release preparation unit Then, the discharge switching element connected in series with the separation target battery is turned off, and the increase in the potential difference due to the discharge of the separation target battery is prevented.

  A storage charge amount detection unit that detects a storage charge amount of the plurality of secondary batteries; and a remaining charge that excludes the separation target battery based on the storage charge amount of each secondary battery detected by the storage charge amount detection unit. A remaining storage amount acquisition unit that acquires the total amount of stored charge of the secondary battery as a remaining storage amount, and the abnormality elimination determination unit determines that the abnormality of the separation target battery has been resolved, and the separation battery voltage and the When the difference from the connected battery voltage exceeds the voltage difference threshold, the disconnected battery voltage is lower than the connected battery voltage, and the remaining storage amount acquired by the remaining storage amount acquisition unit is set in advance. When the threshold value is exceeded, the preparation process by the separation release preparation unit is permitted, and the separation battery voltage is lower than the connection battery voltage and is acquired by the remaining storage amount acquisition unit. When the remaining charged amount is less than the charged amount threshold, the charging switching element and the discharging switching element connected in series with the separation target battery in which the abnormality is resolved by prohibiting the preparation process by the separation release preparation unit It is preferable to further include a remaining power storage amount management unit that turns off the power.

  According to this configuration, the remaining storage amount acquisition unit acquires the total stored charge amount of the remaining secondary batteries excluding the separation target battery, that is, the stored charge amount that can be discharged to the outside as the remaining storage amount. . Here, when the separation battery voltage is lower than the connection battery voltage, when the preparation process by the separation release preparation unit is executed, the secondary battery other than the separation target battery is discharged and the separation target battery is charged to the outside. On the other hand, the amount of stored charge that can be discharged is reduced. Therefore, in such a case, when the remaining power storage amount exceeds a preset power storage amount threshold, the preparation process by the separation release preparation unit is permitted by the remaining power storage amount management unit. In this case, even if a secondary battery other than the separation target battery is discharged by the preparation process, there is little possibility that the remaining power storage amount immediately falls below the power storage amount threshold value. Can be reduced.

  When the separation battery voltage is lower than the connection battery voltage and the remaining storage amount is less than the storage amount threshold value, the remaining storage amount management unit prohibits the preparation process by the disconnection release preparation unit, and the separation target battery in which the abnormality has been resolved The charging switching element connected in series with the battery is turned off, and the charging current of the separation target battery is prevented from being discharged from the secondary battery other than the separation target battery. As a result, the possibility that the remaining power storage amount will further decrease below the power storage amount threshold is reduced, so that the possibility that the amount of stored charge that can be discharged to the outside will be insufficient can be reduced. At this time, since the discharge switching element is also turned off by the remaining power storage amount management unit, the possibility that the separation battery voltage further decreases and the difference between the separation battery voltage and the connection battery voltage increases is reduced.

  Further, the abnormality determination unit uses at least one of a terminal voltage of each secondary battery, a current flowing through each secondary battery, and a temperature of each secondary battery as a parameter for abnormality determination, When the parameter is in an abnormality determination range set in advance to indicate an abnormal state, it is determined that there is an abnormality in the secondary battery that is in the abnormality determination range, and the abnormality elimination determination unit When the parameter used for abnormality determination by the abnormality determination unit falls within a normal determination range set in advance to indicate a normal state, it may be determined that the abnormality of the separation target battery that has become the normal determination range has been resolved. preferable.

  According to this configuration, the terminal voltage of each secondary battery, the current flowing through each secondary battery, and the temperature of each secondary battery are the main parameters that reflect the state of the secondary battery. By using at least one of them as an abnormality determination parameter, it is easy to determine the presence or absence of abnormality in each secondary battery.

  Moreover, the power supply device according to the present invention includes the above-described charge / discharge control circuit and the plurality of secondary batteries.

  According to this configuration, in a power supply device including a plurality of secondary batteries, there is a possibility that a secondary battery once disconnected from a parallel circuit in which the plurality of secondary batteries are connected in parallel may be connected again in parallel. Such an inrush current can be reduced without using a current limiting resistor to reduce the inrush current.

  According to the charge / discharge control circuit and the power supply device having such a configuration, a rush that may occur when a secondary battery once disconnected from a parallel circuit in which a plurality of secondary batteries are connected in parallel is connected again in parallel. Such an inrush current can be reduced without using a current limiting resistor to reduce the current.

It is a block diagram which shows an example of a structure of the power supply device which concerns on one Embodiment of this invention. 3 is a flowchart illustrating an example of an operation of the power supply device illustrated in FIG. 1. 3 is a flowchart illustrating an example of an operation of the power supply device illustrated in FIG. 1. It is explanatory drawing for demonstrating an example of the pulse drive operation | movement of the switching element by the isolation | separation cancellation | release preparation part shown in FIG. It is explanatory drawing for demonstrating the control method of the switching element for charge of the isolation | separation object battery block based on the isolation | separation battery voltage, a connection battery voltage, and the remaining electrical storage amount, and a discharge.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a block diagram illustrating an example of a configuration of a power supply device according to an embodiment of the present invention.

  1 includes battery blocks 2, 3, 4 (secondary batteries), voltage detection units 21, 31, 41, current detection units 22, 32, 42, temperature detection units 23, 33, 43, and discharge. Switching elements 24, 34, 44, charging switching elements 25, 35, 45, a control unit 5, and connection terminals 6, 7. And the part remove | excluding battery block 2,3,4 from the power supply device 1 is equivalent to an example of a charging / discharging control circuit.

  The power generation device 100 and the load device 200 are connected to the connection terminals 6 and 7. The surplus power generated by the power generation device 100 is charged to the battery blocks 2, 3, 4 via the connection terminals 6, 7, or the load device is connected from the battery blocks 2, 3, 4 via the connection terminals 6, 7. 200 load currents are supplied.

  In addition, a series circuit 20 in which the discharging switching element 24, the charging switching element 25, the battery block 2, and the current detection unit 22 are connected in series, the discharging switching element 34, the charging switching element 35, the battery block 3, And the series circuit 30 in which the current detection unit 32 is connected in series, and the series circuit 40 in which the discharge switching element 44, the charging switching element 45, the battery block 4, and the current detection unit 42 are connected in series are connected. The terminals 6 and 7 are connected in parallel.

  Each of the battery blocks 2, 3, and 4 is configured by connecting a plurality of secondary batteries B in series, for example. Each secondary battery B may be, for example, a plurality of unit cells in parallel, series, or a combination battery in which parallel and series are combined, or may be a unit cell. A secondary battery B may be used instead of the battery blocks 2, 3, 4.

  As the single battery constituting each secondary battery B, various secondary batteries such as a lithium ion secondary battery and a nickel hydride secondary battery can be used.

  A plurality of voltage detectors 21 that detect the terminal voltage of each secondary battery B in the battery block 2, a plurality of voltage detectors 31 that detect the terminal voltage of each secondary battery B in the battery block 3, and the battery block 4. Are provided with a plurality of voltage detectors 41 for detecting the terminal voltage of each secondary battery B. In addition, the voltage detection parts 21, 31, and 41 are not restricted to the example which detects the terminal voltage of each secondary battery B, The structure which detects each terminal voltage of the battery blocks 2, 3, and 4 may be sufficient.

  The temperature detectors 23, 33, and 43 are configured using, for example, a temperature sensor such as a thermistor or a thermocouple, an analog-digital converter, and the like. The temperature detectors 23, 33, and 43 are provided in the vicinity of the battery blocks 2, 3, and 4 to detect the temperatures of the battery blocks 2, 3, and 4.

  Each of the temperature detection units 23, 33, and 43 may include a plurality of temperature sensors and detect the temperatures of the plurality of secondary batteries B included in the battery blocks 2, 3, and 4, or each battery. One temperature sensor may be provided for two secondary batteries B adjacent in the block, and the temperature may be detected for each of the two secondary batteries B. If a temperature sensor is arranged between adjacent secondary batteries B so that the temperature is detected for every two secondary batteries B, the number of temperature sensors is reduced while ensuring the accuracy of temperature detection. Thus, the cost can be reduced.

  When each of the temperature detection units 23, 33, and 43 includes a plurality of sensors, for example, the highest temperature among the temperatures of the secondary batteries B detected in the battery blocks 2, 3, and 4 is set to the battery blocks 2 and 3. , 4 can be used as each temperature.

  The current detection units 22, 32, and 42 are configured using, for example, a shunt resistor, a current transformer, an analog digital converter, or the like. Then, the current detection units 22, 32, 42 output, for example, a signal that represents the charging current of the battery blocks 2, 3, 4 with a positive current value and the discharge current with a negative current value to the control unit 5.

  As the discharge switching elements 24, 34, 44 and the charge switching elements 25, 35, 45, for example, p-channel FETs (Field Effect Transistors) and n-channel FETs are used. The discharging switching elements 24, 34, 44 are connected in a direction in which the charging current of the battery blocks 2, 3, 4 is in the forward direction of the parasitic diode, and the charging switching elements 25, 35, 45 are connected to the battery block 2. , 3 and 4 are connected in such a direction that the forward direction of the parasitic diodes.

  As a result, the discharging switching elements 24, 34, and 44 are designed to turn on and off only in the discharging direction while constantly flowing in the charging direction. Further, the charging switching elements 25, 35, and 45 are designed to turn on and off only the current in the charging direction while the current in the discharging direction always flows.

  In addition, although the example where the three series circuits 20, 30, and 40 are connected in parallel is shown, the series circuit is not limited to three as long as a plurality of series circuits are connected in parallel.

  The control unit 5 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a nonvolatile ROM (Read Only Memory) that stores a predetermined control program, and a RAM (Random) that temporarily stores data. Access Memory) and its peripheral circuits and the like. Then, the control unit 5 executes, for example, a control program stored in the ROM, so that the abnormality determination unit 51, the separation control unit 52, the abnormality elimination determination unit 53, the separation release unit 54, the separation release preparation unit 55, the stored charge It functions as an amount detection unit 56, a remaining storage amount acquisition unit 57, and a remaining storage amount management unit 58.

  The abnormality determination unit 51 determines whether or not each battery block 2, 3, 4 is abnormal. Specifically, the abnormality determination unit 51 uses, for example, the terminal voltage of each secondary battery B detected by the voltage detection units 21, 31, 41 as a parameter, and any one of the terminal voltages is excessive. When the abnormality determination range is set to the voltage range indicating charging or the voltage range indicating overdischarge, it is determined that there is an abnormality in the battery block including the secondary battery B in the abnormality determination range.

  In addition, the abnormality determination part 51 is the overcharge of each battery block, for example, either of the total value for each battery block of the terminal voltage of each secondary battery B detected by the voltage detection part 21,31,41. Or an abnormal determination range set in a voltage range indicating overdischarge, it may be determined that there is an abnormality in the battery block in the abnormal determination range.

  In addition, the abnormality determination unit 51 uses, for example, a current value flowing through each battery block detected by the current detection units 22, 32, and 42 as a parameter, and any one of the current values indicates a current indicating an overcurrent. When the abnormality determination range set in the range is reached, it is determined that there is an abnormality in the battery block in the abnormality determination range.

  In addition, the abnormality determination unit 51 uses, for example, the temperature of each battery block detected by the temperature detection units 23, 33, and 43 as a parameter, and any one of the temperatures indicates an excessively high temperature state. When the abnormality determination range is set to, it is determined that there is an abnormality in the battery block that is in the abnormality determination range.

  In addition, although the abnormality determination part 51 showed the example which determines the abnormality of a battery block based on the parameter of a voltage, an electric current, and temperature, using only any one among a voltage, an electric current, and temperature, The abnormality may be determined, and the abnormality may be detected based on conditions other than voltage, current, and temperature.

  When the abnormality determination unit 51 determines that any of the battery blocks is abnormal, the disconnection control unit 52 sets the battery block determined to be abnormal as a separation target battery block (detachment target battery), The discharging switching element and the charging switching element connected in series with the separation target battery block are turned off, and the separation target battery block is separated from the other battery blocks.

  The abnormality elimination determination unit 53 determines whether or not the abnormality of the separation target battery block has been eliminated. Specifically, when the parameter used for abnormality determination by the abnormality determination unit 51 is in a normal determination range indicating a normal state with respect to the separation target battery block, the abnormality elimination determination unit 53 enters the normal determination range. It is determined that the abnormality of the separation target battery has been resolved.

  The disconnection release unit 54 determines that the abnormality of the separation target battery block has been resolved by the abnormality elimination determination unit 53, and the separation battery voltage Verr that is the terminal voltage of the separation target battery block in which the abnormality has been resolved, and the separation target battery block When the difference voltage Vd, which is the absolute value of the difference from the connected battery voltage Vn, which is the terminal voltage of the battery block other than the battery block, is less than the preset voltage difference threshold Von, the battery block is connected in series with the separation target battery block in which the abnormality has been resolved. The connected discharging switching element and charging switching element are turned on.

  As the separation battery voltage Verr, the total value in the block of the terminal voltage of each secondary battery B detected by the voltage detection unit is used as the terminal voltage of the separation target battery block in which the abnormality has been resolved. Further, as the connection battery voltage Vn, the total value for each battery block of the terminal voltage of each secondary battery B detected by the voltage detection unit is used as the terminal voltage of the battery blocks other than the separation target battery block.

  Here, since the battery blocks other than the separation target battery block are connected in parallel, the terminal voltages of the battery blocks (the total value of the terminal voltages of the secondary battery B for each battery block) are equal. Therefore, any one of the terminal voltages of the battery blocks other than the separation target battery block may be used as the connection battery voltage Vn. In addition, you may make it use the average value of the terminal voltage of each battery block other than the separation object battery block as the connection battery voltage Vn.

  In addition, when the separation target battery block that is separated from the other battery block is connected to the other battery block, the current flowing between the separation target battery block and the other battery block due to the differential voltage Vd is A differential voltage Vd that causes a large current that may cause deterioration of the secondary battery B or a voltage fluctuation between the connection terminals 6 and 7 is set in advance as the voltage difference threshold Von. Has been.

  The separation release preparation unit 55 determines that the abnormality of the separation target battery block has been resolved by the abnormality elimination determination unit 53, and the difference between the separation battery voltage Verr and the connection battery voltage Vn is equal to or greater than the voltage difference threshold Von. In order to reduce the possibility of the above-described large current flowing when the separation target battery block is connected to another battery block, the following preparation process is executed.

  When the detachment battery voltage Verr is higher than the connection battery voltage Vn, the detachment release preparation unit 55 turns off the charging switching element connected in series with the detachable battery block in which the abnormality is eliminated as a preparation process, and the detachment target battery block By periodically turning on and off the discharge switching element connected in series in a pulsed manner, the current value output from the battery block to be disconnected is limited to a low level that does not adversely affect the target to be disconnected. The battery block is discharged to reduce the differential voltage Vd.

  Note that when the separation battery voltage Verr is higher than the connection battery voltage Vn, the separation release preparation unit 55 does not necessarily flow in the direction in which the separation target battery block is charged from the battery blocks other than the separation target battery block. It is not necessary to turn off the charging switching element connected in series with the separation target battery block in which the abnormality is eliminated. However, by turning off the charging switching element, for example, the charging current from the power generation device 100 connected to the connection terminals 6 and 7 is also cut off, and the battery block to be separated is more reliably charged. It is possible to prevent the differential voltage Vd from increasing.

  On the other hand, when the separation battery voltage Verr is lower than the connection battery voltage Vn, the separation release preparation unit 55 turns off the discharge switching element connected in series with the separation target battery block in which the abnormality has been eliminated as a preparation process, By periodically turning on and off the charging switching elements connected in series with the battery block, the current flowing into the battery block to be disconnected is limited to a low level that does not adversely affect the object to be disconnected. The battery block is charged and the differential voltage Vd is decreased.

  In addition, when the separation battery voltage Verr is lower than the connection battery voltage Vn, the separation release preparation unit 55 does not cause a current to flow in the direction in which the separation target battery block is discharged to another battery block even if the discharge switching element is turned on. Therefore, it is not always necessary to turn off the discharge switching element connected in series with the separation target battery block in which the abnormality is resolved. However, by turning off the discharge switching element, for example, the current flowing to the load device 200 connected to the connection terminals 6 and 7 is also cut off, and the separation target battery block is discharged more reliably and more reliably. It is possible to prevent the voltage Vd from increasing.

  Note that it is not always necessary to form a switching unit by the discharging switching element and the charging switching element. For example, a relay switch or a parasitic diode is not provided in place of the series circuit of the discharging switching element and the charging switching element. A single switching element that can control the current in both directions, such as an FET, may be used as the switching unit.

  When a single switching element capable of controlling the current in both directions is used as the switching unit, the disconnection release preparation unit 55 performs the preparation process regardless of the magnitude relationship between the disconnection battery voltage Verr and the connection battery voltage Vn. The switching element may be configured to periodically turn on and off in a pulsed manner.

  The stored charge amount detection unit 56 detects the stored charge amount of the battery blocks 2, 3, and 4. Specifically, the stored charge amount detection unit 56, for example, continuously accumulates each current value detected by the current detection units 22, 32, and 42, for example, every unit time, whereby the battery block 2 , 3 and 4 are respectively calculated.

  The stored charge amount detection unit 56 is detected by the voltage detection units 21, 31, 41 using, for example, the correlation between the terminal voltage of the battery blocks 2, 3, 4 and the stored charge amount. The terminal voltage of the battery blocks 2, 3, 4 (the total value of the terminal voltages of the secondary battery B in each battery block) may be converted into the stored charge amount of the battery blocks 2, 3, 4.

  Further, the stored charge amount detection unit 56 may be configured to correct the stored charge amount of each battery block thus obtained based on the temperatures detected by the temperature detection units 23, 33, and 43.

  Based on the stored charge amount of the battery blocks 2, 3, and 4 detected by the stored charge amount detection unit 56, the remaining stored charge amount acquisition unit 57 calculates the remaining stored charge amount of the remaining battery blocks excluding the separation target battery. Obtained as quantity Qr. For example, when the total charge capacity of the battery blocks 2, 3, 4, that is, the full charge capacity of the entire power supply device 1 is set to Qfull, the remaining power storage amount acquisition unit 57 stores the remaining power storage amount with respect to the full charge capacity Qfull. By expressing the ratio of Qr as a percentage, PSOC in which the remaining power storage amount Qr is expressed in SOC (State Of Charge) may be calculated.

  Hereinafter, an example in which the remaining power storage amount Qr is expressed as PSOC will be described.

  The remaining storage amount management unit 58 disconnects when the separation battery voltage Verr is lower than the connection battery voltage Vn and the remaining storage amount PSOC calculated by the remaining storage amount acquisition unit 57 exceeds a preset storage amount threshold SOCt. The preparation process by the release preparation unit 55 is permitted. On the other hand, when the separated battery voltage Verr is lower than the connected battery voltage Vn and the remaining storage amount PSOC calculated by the remaining storage amount acquisition unit 57 is less than the storage amount threshold SOCt, the remaining storage amount management unit 58 releases the separation. The charging switching element and the discharging switching element connected in series with the separation target battery whose abnormality has been eliminated by prohibiting the preparation process by the preparation unit 55 are turned off.

  As the power storage amount threshold SOCt, for example, an SOC (charge amount) that needs to be constantly secured in order to stably operate the load device 200 is set in advance, for example, 40%.

  As a result, when the remaining storage amount PSOC is less than the storage amount threshold SOCt, and therefore the SOC (charge amount) that needs to be secured at all times in a state where the power supply device 1 can be discharged is insufficient, switching for charging is performed. When the element is turned on, the charging current flows from the battery block other than the separation target battery, that is, the battery block capable of supplying power to the load device 200, to the separation target battery, and the remaining storage amount PSOC is further reduced. Is to be prevented.

  Next, the operation of the power supply device 1 configured as described above will be described. 2 and 3 are flowcharts showing an example of the operation of the power supply device 1 shown in FIG. First, the voltage, current, and temperature of the battery blocks 2, 3, and 4 are detected as battery information by the voltage detectors 21, 31, and 41, the current detectors 22, 32, and 42, and the temperature detectors 23, 33, and 43. (Step S1).

  Next, the stored charge amount detection unit 56 calculates the stored charge amounts charged in the battery blocks 2, 3, and 4 based on the battery information obtained in step S1. Then, the remaining power storage amount PSOC is calculated by the remaining power storage amount acquisition unit 57 (step S2).

  Specifically, for example, if there is no battery block that is set as a separation target battery block in step S4 described below, the battery blocks 2, 3, and 4 calculated by the remaining charge amount detection unit 56 by the remaining charge amount acquisition unit 57 Is calculated as the remaining storage amount Qr, and the remaining storage amount PSOC is calculated from the remaining storage amount Qr and the full charge capacity Qfull.

  For example, when the battery block 2 is a separation target battery block, the remaining storage amount acquisition unit 57 calculates the remaining storage amount of the battery blocks 3 and 4 calculated by the stored charge amount detection unit 56 as the remaining storage amount. The remaining amount of charge PSOC is calculated from the remaining amount of charge Qr and the full charge capacity Qfull.

  Next, the abnormality determination unit 51 determines whether or not the battery blocks 2, 3, and 4 are abnormal using the battery information detected in step 1 (step S3). (NO in step S3), steps S1 to S3 are repeated again. On the other hand, if any of them is abnormal (YES in step S3), the disconnection control unit 52 sets the abnormal battery block as the target battery block to be disconnected, and the switching element for discharging and charging of the target battery block to be disconnected. The battery block to be disconnected is disconnected from the other battery blocks (step S4).

  For example, when it is determined in step S3 that the battery block 2 is abnormal, the discharging switching element 24 and the charging switching element 25 are turned off. Thereby, for example, the battery block 2 in which some abnormality such as an overcharged state, an overdischarged state, or a high temperature state is further charged / discharged can reduce a possibility that safety is lowered.

  Next, it is determined by the abnormality elimination determination unit 53 whether or not the abnormality of the separation target battery block has been eliminated (step S5).

  If the abnormality has not been resolved (NO in step S5), steps S1 to S5 are repeated again while the separation target battery block is disconnected from the other battery blocks. On the other hand, if the abnormality has been resolved (YES in step S5), the separation release unit 54 acquires the terminal voltage of the separation target battery block whose abnormality has been resolved as the separation battery voltage Verr (step S6), and the separation target battery block The average value of the terminal voltages of the other battery blocks is acquired as the connection battery voltage Vn (step S7).

  Further, the absolute value of the difference between the separated battery voltage Verr and the connected battery voltage Vn is calculated as the differential voltage Vd by the separation release unit 54 (step S8).

  Next, the separation release unit 54 compares the difference voltage Vd with the voltage difference threshold value Von (step S11). As a result, when the differential voltage Vd is smaller than the voltage difference threshold Von (YES in step S11), even if the separation of the separation target battery block whose abnormality has been resolved is released, the separation target battery block and another battery block are not separated. Therefore, it is possible to determine that there is no possibility that a large current that would cause inconvenience flows through the disconnection release unit 54, the switching element for discharging and charging of the battery to be disconnected is turned on, and the disconnection is released (step S12). The process proceeds to step S1 again.

  The battery block set as the separation target battery block is handled as a normal battery block (battery block other than the separation target battery block) after the separation is released.

  For example, when the battery block 2 is set as the separation target battery block and the differential voltage Vd is smaller than the voltage difference threshold Von, the discharging switching element 24 and the charging switching element 25 are turned on in step S12, and the separation is released. Thereafter, the battery block 2 is no longer the battery block to be disconnected.

  On the other hand, if the differential voltage Vd is equal to or greater than the voltage difference threshold Von (NO in step S11), if the disconnection is temporarily cancelled, an inconvenience may occur between the target battery block to be disconnected and another battery block. Since it can be determined that a large current may flow, the process proceeds to step S13 to execute a preparation process for reducing the differential voltage Vd so that the separation can be released.

  Next, in step S13, the disconnection release preparation unit 55 compares the disconnection battery voltage Verr and the connection battery voltage Vn (step S13). As a result, when the detachable battery voltage Verr is equal to or higher than the connected battery voltage Vn (YES in step S13), the process proceeds to step S14, and the detachment release preparation unit 55 determines the switching element for charging the detachable battery block whose abnormality has been eliminated. Off, the discharge switching element is pulse-driven (step S14).

  FIG. 4 is an explanatory diagram for explaining an example of the pulse driving operation of the switching element by the separation release preparation unit 55. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the on / off operation of the switching element to be controlled among the switching element for discharging and the switching element for charging.

  The switch-on period Ton is a period for turning on the switching element, and the switch-off period Toff is a period for turning off the switching element. The switch-on period Ton and the switch-off period Toff are repeated with a cycle Tcyc.

  The switch-on period Ton is set to an appropriate time such that the battery blocks 2, 3, 4 are not deteriorated and the series circuits 20, 30, 40 are not thermally destroyed. The switch-off period Toff is set so that the average value of the current flowing between the battery blocks according to the differential voltage Vd during the period Tcyc is a low-level current value that does not adversely affect the switch-off period Toff. Yes.

  As the switch-on period Ton, for example, 100 ms can be used, and as the switch-off period Toff, for example, 900 ms can be used.

  Specifically, for example, the battery block 2 is set as a separation target battery block, and the separation battery voltage Verr of the battery block 2 is a connection battery voltage that is an average value of the terminal voltages of the battery blocks 3 and 4 that are not separated. When it is Vn or higher, in step S14, the separation release preparation unit 55 drives the discharge switching element 24 in a pulse manner.

  As a result, since current gradually flows from the battery block 2 to the battery blocks 3 and 4, the battery block 2 and the battery blocks 3 and 4 are prevented while preventing deterioration of the battery blocks 3 and 4 and thermal destruction of the series circuits 30 and 40. The differential voltage Vd, which is the terminal voltage difference between, can be reduced. Further, the power supply device 1 always needs to ensure a certain amount of the stored charge amount that can be output that is equal to or greater than the charge amount threshold SOCt, but if the disconnected battery voltage Verr is equal to or greater than the connected battery voltage Vn (in step S13). YES), the battery blocks 3 and 4 are charged with the current flowing from the battery block 2, or the current does not flow, so the amount of output stored charge that must be secured as the power supply device 1 is increased or maintained. There is no problem.

  On the other hand, if the disconnecting battery voltage Verr is smaller than the connected battery voltage Vn in step S13 (NO in step S13), the process proceeds to step S15.

  Next, in step 15, the remaining power storage amount management unit 58 compares the remaining power storage amount PSOC with the power storage amount threshold SOCt (step S15). As a result, when the remaining storage amount PSOC is larger than the storage amount threshold SOCt (YES in step S15), the preparation processing by the separation release preparation unit 55 is permitted, and the separation target battery block whose abnormality has been eliminated by the separation release preparation unit 55 The charging switching element is pulse-driven, and the discharging switching element is turned off (step S16).

  Specifically, for example, when the battery block 2 is set as a separation target battery block, and the remaining power storage amount PSOC of the power supply device 1 secured by the battery blocks 3 and 4 is larger than the power storage amount threshold SOCt (in step S15) YES), the switching element 25 for charging is pulse-driven by the separation release preparation unit 55 (step S16).

  As a result, current flows little by little from the battery blocks 3 and 4 to the battery block 2, so that the terminal block voltage difference between the battery block 2 and the battery blocks 3 and 4 is prevented while preventing deterioration of the battery block 2 and thermal destruction of the series circuit 20. A certain differential voltage Vd can be reduced. In addition, the power supply device 1 must always secure a certain amount of the stored charge amount that can be output that is equal to or greater than the charge amount threshold SOCt, but the remaining charge amount PSOC of the power supply device 1 secured by the battery blocks 3 and 4 is Since it is larger than the charged amount threshold SOCt, there is no problem even if the remaining charged amount PSOC decreases.

  Then, when the differential voltage Vd is decreased and falls below the voltage difference threshold Von in step S14 or step S16 (YES in step S11), the disconnection release unit 54 causes the switching element for discharging and charging of the battery to be disconnected to be disconnected. It is turned on and the separation is released (step S12).

  On the other hand, in step S15, when the remaining storage amount PSOC is equal to or less than the storage amount threshold SOCt (NO in step S15), the remaining storage amount management unit 58 prohibits the preparation process by the disconnection release preparation unit 55, and the disconnection in which the abnormality has been resolved. The switching element for charging and discharging the target battery block is turned off (step S17).

  Specifically, for example, when the battery block 2 is set as the separation target battery block, and the remaining power storage amount PSOC of the power supply device 1 secured by the battery blocks 3 and 4 is equal to or less than the power storage amount threshold SOCt (NO in step S15) ) The remaining storage amount management unit 58 turns off both the discharging switching element 24 and the charging switching element 25.

  As a result, when the chargeable switching element 25 of the battery block 2 is turned on in a state where the stored charge amount exceeding the stored charge amount threshold SOCt that needs to be secured at all times is not secured in the dischargeable battery blocks 3 and 4 In addition, it is possible to prevent the remaining remaining charge amount PSOC from being further reduced due to the current flowing from the battery blocks 3 and 4 to the battery block 2. In such a case, it is necessary to wait until the remaining power storage amount PSOC becomes larger than the power storage amount threshold SOCt by charging the battery blocks 3 and 4 with the power generation device 100.

  According to steps S13 to S17, as shown in the explanatory diagram of FIG. 5, the control method of the switching element for charging and discharging of the battery block to be disconnected based on the disconnected battery voltage Verr, the connected battery voltage Vn, and the remaining storage amount PSOC. Is determined.

  Note that it is not always necessary to include the stored charge amount detection unit 56, the remaining stored charge amount acquisition unit 57, and the remaining stored charge amount management unit 58. Steps S2, S15, and S17 are not executed, and in step S13, the disconnected battery voltage Verr is When the voltage is smaller than the connected battery voltage Vn (NO in step S13), the configuration may be shifted to step S16.

  As mentioned above, according to the process of step S1-S17, in order to reduce the inrush current which may arise when the secondary battery once disconnected from the parallel circuit where the several secondary battery was connected in parallel is connected in parallel again. The risk of such inrush current can be reduced without using any current limiting resistor. This makes it possible to reduce the size and cost of the power supply device.

  The battery device according to the present invention is equipped with a battery such as a portable personal computer, a digital camera, an electronic device such as a mobile phone, a vehicle such as an electric vehicle or a hybrid car, a power source system combining a solar cell, a power generator and a secondary battery. It can be suitably used in devices, systems, and the like.

DESCRIPTION OF SYMBOLS 1 Power supply device 2,3,4 Battery block 5 Control part 6,7 Connection terminal 20,30,40 Series circuit 21,31,41 Voltage detection part 22,32,42 Current detection part 23,33,43 Temperature detection part 24 , 34, 44 Switching element for discharging 25, 35, 45 Switching element for charging 51 Abnormality determining unit 52 Detaching control unit 53 Abnormality canceling determining unit 54 Detaching release unit 55 Detaching release preparation unit 56 Accumulated charge amount detection unit 57 Acquisition of remaining electric charge amount Unit 58 Remaining storage amount management unit 100 Power generation device 200 Load device B Secondary battery PSOC Remaining storage amount Qfull Fully charged capacity Qr Remaining storage amount SOCt Storage amount threshold Tcyc cycle Toff Switch-off period Ton Switch-on period Vd Differential voltage Verr Disconnected battery voltage Vn Connection battery voltage Von Voltage difference threshold

Claims (7)

A plurality of secondary batteries connected in parallel and a plurality of switching units each connected in series;
A terminal voltage detector for detecting a terminal voltage of each of the secondary batteries;
An abnormality determination unit that determines whether or not each of the secondary batteries is abnormal;
When one of the secondary batteries is determined to be abnormal by the abnormality determination unit, the secondary battery determined to be abnormal is set as a separation target battery, and switching connected in series with the separation target battery A separation control unit for turning off the unit,
An abnormality elimination determination unit for judging whether or not the abnormality of the separation target battery has been eliminated;
The disconnection battery voltage, which is the terminal voltage detected by the terminal voltage detection unit in the disconnection target battery in which the abnormality is determined to be resolved by the abnormality elimination determination unit and the abnormality is resolved, and the separation target If the difference between the secondary battery other than the battery and the connected battery voltage, which is the terminal voltage detected by the terminal voltage detector, is less than the preset voltage difference threshold, it is in series with the battery to be disconnected in which the abnormality has been resolved. A disconnection release unit for turning on the connected switching unit;
When the abnormality elimination determination unit determines that the abnormality of the separation target battery has been resolved, and the difference between the separation battery voltage and the connection battery voltage exceeds the voltage difference threshold, the separation target battery in which the abnormality is resolved And a disconnection release preparation unit that executes a preparation process for turning on and off the switching unit connected in series in a pulsed manner. A stored charge amount detection unit for detecting a stored charge amount of the plurality of secondary batteries;
Based on the stored charge amount of each secondary battery detected by the stored charge amount detection unit, the remaining stored charge amount acquisition unit acquires the total stored charge amount of the remaining secondary batteries excluding the separation target battery as the remaining stored charge amount. When,
When the abnormality elimination determination unit determines that the abnormality of the separation target battery has been resolved and the difference between the separation battery voltage and the connected battery voltage exceeds the voltage difference threshold, the remaining power storage amount acquisition unit When the acquired remaining storage amount exceeds a preset storage amount threshold, the preparation processing by the disconnection release preparation unit is permitted, and the remaining storage amount acquired by the remaining storage amount acquisition unit becomes the storage amount threshold. And a remaining storage amount management unit that turns off the switching unit connected in series with the separation target battery in which the abnormality has been resolved by prohibiting the preparation process by the separation release preparation unit when not satisfied. Item 2. The charge / discharge control circuit according to Item 1. Each of the switching units is
Each of the secondary batteries, a charging switching element that prohibits charging and a discharging switching element that prohibits discharging are connected in series,
The detachment release preparation unit, as the preparation process,
When the disconnection battery voltage is higher than the connection battery voltage, the discharge switching element connected in series with the disconnection target battery is turned on and off in pulses,
The charge / discharge control circuit according to claim 1, wherein when the separation battery voltage is lower than the connection battery voltage, the charging switching element connected in series with the separation target battery is turned on and off in a pulsed manner. In the preparation process, the separation release preparation unit further includes:
When the disconnection battery voltage is higher than the connection battery voltage, the switching element for charging connected in series with the disconnection target battery in which the abnormality has been resolved is turned off,
The charge / discharge control circuit according to claim 3, wherein when the separation battery voltage is lower than the connection battery voltage, the switching element for discharge connected in series with the separation target battery is turned off. A stored charge amount detection unit for detecting a stored charge amount of the plurality of secondary batteries;
Based on the stored charge amount of each secondary battery detected by the stored charge amount detection unit, the remaining stored charge amount acquisition unit acquires the total stored charge amount of the remaining secondary batteries excluding the separation target battery as the remaining stored charge amount. When,
When it is determined that the abnormality of the separation target battery has been eliminated by the abnormality elimination determination unit, and the difference between the separation battery voltage and the connection battery voltage exceeds the voltage difference threshold, the separation battery voltage is the connection When the remaining storage amount acquired by the remaining storage amount acquisition unit is lower than the battery voltage and exceeds a preset storage amount threshold, the preparation processing by the disconnection release preparation unit is permitted, and the disconnected battery voltage is When the remaining storage amount acquired by the remaining storage amount acquisition unit is lower than the connected battery voltage and less than the storage amount threshold, the preparation target by the disconnection release preparation unit is prohibited and the abnormality is resolved And a remaining power storage amount management unit that turns off the charging switching element and the discharging switching element connected in series with the battery. Charge and discharge control circuit according to claim 3 or 4, wherein the door. The abnormality determination unit uses at least one of a terminal voltage of each secondary battery, a current flowing through each secondary battery, and a temperature of each secondary battery as a parameter for abnormality determination, and the parameter is When the abnormality determination range is set in advance to indicate an abnormal state, it is determined that there is an abnormality in the secondary battery that is in the abnormality determination range,
The abnormality elimination determination unit
When the parameter used for abnormality determination by the abnormality determination unit is in a normal determination range that is set in advance to indicate a normal state, the abnormality of the separation target battery that has become the normal determination range is detected. The charge / discharge control circuit according to claim 1, wherein the charge / discharge control circuit is determined to be eliminated. The charge / discharge control circuit according to any one of claims 1 to 6,
A power supply device comprising the plurality of secondary batteries.

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