WO2014156041A1

WO2014156041A1 - Power supply system and charging and discharging control method for power supply system

Info

Publication number: WO2014156041A1
Application number: PCT/JP2014/001503
Authority: WO
Inventors: 山口　昌男; 貴功原田; 和宏瀬尾
Original assignee: 三洋電機株式会社
Priority date: 2013-03-29
Filing date: 2014-03-17
Publication date: 2014-10-02
Also published as: CN104247198A; JP5615995B1; CN104247198B; JPWO2014156041A1

Abstract

A power supply system is provided with an external power supply (3), a plurality of battery units (2), and a connection unit (1). The power supply system provides power from the external power supply (3) to each of the battery units (2) so as to charge the battery units, and in a state where the output from the external power supply (3) is reduced, the battery units (2) provide power to a device to be driven (40). The connection unit (1) is provided with a parallel line (8) that connects the battery units (2) in parallel, connectors (9) that connect each battery unit (2) to the parallel line (8), and a control unit (10) that controls the connection states of the connectors (9). The connection unit (1) is connected to the power supply line (5) of the external power supply (3) via an external connection switch (7). The control unit (10) charges and discharges the plurality of battery units (2) while switching between an equalization charging mode in which precharging is performed while each of the battery units (2) is equalized, a normal charging mode, a fully charged mode, a normal discharging mode in which power is supplied from each of the battery units (2) to the power supply line (5), a discharge stopping mode, and a drive stopping mode.

Description

Power supply system and charge / discharge control method for power supply system

The present invention relates to a power supply system that charges a battery unit including a plurality of battery cells with power supplied from a commercial power source and outputs the power of the charged battery unit when the power supplied from the commercial power source is reduced. In particular, the present invention relates to a power supply system in which the power of a commercial power supply is stored in a plurality of battery units to increase the output, and a charge / discharge control method for the power supply system.

A backup power supply device that is connected to a mobile phone base station or a traffic light and supplies power in the event of a commercial power failure is known. Such a backup power source is connected to the drive target device, and is configured to supply predetermined power to the drive target device when it is detected that an abnormality has occurred in the commercial power source.

International Publication No. 2012/043723

In such a backup power supply device, it is conceivable to connect a plurality of battery units in parallel in order to increase the capacity and enable long-time power supply. However, in this case, if the output voltages of the plurality of battery units do not match, there is a problem in that a part of the output is not supplied to the drive target device and a problem such as being supplied to another battery unit occurs. there were.

The present invention has been made to solve such conventional problems, and its main purpose is to charge a plurality of battery units equally while connecting a plurality of battery units in parallel to increase the capacity. Another object of the present invention is to provide a power supply system that can be stably used and a charge / discharge control method for the power supply system.

In order to solve the above-described problem, according to the power supply system of the present invention, the external power supply 3 connected to the external commercial power supply 30, converts the power supplied from the commercial power supply 30, and supplies the converted power to the drive target device 40. A plurality of battery units 2 including a plurality of battery cells 21 connected in series; and a connection unit 1 that connects the plurality of battery units 2 in parallel and connects to the external power source 3. Power is supplied to each battery unit 2 to charge the battery cell 21, and the voltage output from the external power supply 3 to the drive target device 40 is reduced from the battery unit 2 to the drive target device 40. To supply power. The external power supply 3 is connected to the power supply circuit 4 for converting alternating current supplied from the commercial power supply 30 into direct current of a predetermined output voltage that drives the drive target device 40, and to the output side of the power supply circuit 4, The power supply line 5 that supplies power to the drive target device 40, the connection line 6 that is connected to the power supply line 5 and connects the connection unit 1, and the power supply line 5 provided on the connection line 6 An external connection switch 7 is provided which is turned off when the voltage of the line 5 becomes a predetermined value or less. The connection unit 1 includes a parallel line 8 that connects the plurality of battery units 2 in parallel, a connection unit 9 that connects each battery unit 2 to the parallel line 8, and a control that controls the connection state of the connection unit 9. And the parallel line 8 is connected to the connection line 6 of the external power source 3, and the connection part 9 is connected in series between the parallel line 8 and each battery unit 2. A series circuit of the first switch 11 and the second switch 12, a sub-connection circuit 15 connected in parallel with the second switch 12, and comprising a series circuit of the current limiting resistor 14 and the third switch 13, and the first switch A first rectifying element 16 connected in parallel to the switch 11 and having a rectifying action in a direction of energizing the battery unit 2 from the parallel line 8; and connected in parallel to the second switch 12; The unit 2 and a second rectifier element 17 having a rectification action in a direction to energize the said parallel line 8. In the power supply system, the control unit 10 precharges each battery unit 2 with the first switch 11 of each connection unit 9 turned off, the second switch 12 turned off, and the third switch 13 turned on. After the balance charging mode and the balance charging mode, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, turns off the third switch 13, and The normal charging mode for fully charging the battery unit 2 and when each battery unit 2 is fully charged, the control unit 10 turns on the first switch 11 of each connection unit 9 and turns off the second switch 12. In the full charge mode in which the charging of the battery unit 2 is stopped by turning off the third switch 13 and in the full charge mode, the output power of the external power source 3 is When the control unit 10 decreases, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, and turns off the third switch 13. In the normal discharge mode for supplying power to the power supply line 5 and in the normal discharge mode, when the voltage of the power supply line 5 becomes equal to or lower than the predetermined value, the external connection switch 7 is controlled to be OFF, and each battery unit When the cell voltage of the battery unit 2 falls below a predetermined value in the discharge stop mode in which the discharge from 2 is stopped and the discharge stop mode, the control unit 10 turns off the first switch 11 of each connection unit 9. The plurality of battery units 2 are charged and discharged by switching between the drive stop mode in which the second switch 12 is turned off and the third switch 13 is turned off. .

With the above configuration, a plurality of battery units connected in parallel can be charged while being equalized. In particular, in the balance charge mode, after precharging while equalizing the battery units with a voltage difference, it is fully charged in the normal charge mode, so that the battery is fully charged while suppressing variations in the state of charge, and the power is discharged when the battery is discharged. You can avoid situations that are exchanged between units. In addition, since each battery unit is precharged in the balance charge mode and then fully charged by switching to the normal charge mode, power supply to the drive target device becomes unstable by allocating a large amount of power to charge the battery unit. The situation can also be avoided, and hot standby is also possible in which the battery units are charged in parallel while the operation of the drive target device is continued.

Further, according to the power supply system of the present invention, in the full charge mode, the remaining capacity of any battery cell 21 of the battery unit 2 decreases by a predetermined rate from the fully charged state, or any battery cell 21 When the cell voltage becomes equal to or lower than the charging restart voltage, the control unit 10 turns on the first switch 11 of each connection unit 9, turns off the second switch 12, and turns on the third switch 13. The battery unit can be recharged by shifting to a recharge mode in which 2 is precharged.

According to the above configuration, when the full charge mode is continued for a long time and the remaining capacity of one of the battery cells decreases, the charging of the battery unit is resumed. Therefore, the remaining capacity of the plurality of battery units is always set to a sufficient remaining capacity. It can be maintained and can be supplied for a long time in an emergency such as a power failure. Moreover, in the recharge mode, a large inrush current can be prevented by precharging the battery unit.

Furthermore, according to the power supply system of the present invention, when the output voltage of the external power supply 3 decreases in the full charge mode or the recharge mode, the power of each battery unit 2 is turned on with the second rectifying element 17. Is supplied to the parallel line 8 via the first switch 11 and the power of the parallel line 8 is supplied to the power supply line 5 of the external power supply 3 via the external connection switch 7 in the ON state. A plurality of battery units 2 can be discharged in the preliminary discharge mode.

According to the above configuration, when the output voltage of the external power supply decreases in the full charge mode or the recharge mode, the power of each battery unit is supplied to the second rectifying element, the first switch in the ON state, and the external in the ON state. Since a plurality of battery units are discharged by the preliminary discharge mode supplied to the power supply line via the connection switch, a connection unit is not provided in the control unit without providing a mechanism for detecting a voltage drop of the commercial power source or the external power source. Without switching the power, it is possible to quickly supply power to the power supply line while the output voltage of the external power supply decreases.

Furthermore, according to the power supply system of the present invention, the connection unit 1 includes the current detection unit 25 that detects the energization state of the connection line 6 of the external power supply 3, and the current detection unit in the preliminary discharge mode. When 25 detects a discharge current to the connection line 25, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, and turns off the third switch 13. The electric power of each battery unit 2 is supplied to the parallel line 8 via the second switch 12 in the ON state and the first switch 11 in the ON state, and the external connection switch in which the power of the parallel line 8 is in the ON state. 7 to the normal discharge mode supplied to the power supply line 5 of the external power source 3 through the battery 7, and the battery units 2 can be discharged.

According to the above configuration, in the state where the current detection unit detects the discharge current, the first switch of each connection unit is turned on, the second switch is turned on, and the third switch is turned off to switch from the preliminary discharge mode to the normal discharge mode. The normal discharge mode can be switched while confirming the discharge state to the connection line. Further, in the normal discharge mode, each battery unit is discharged through the second switch in the ON state and the first switch in the ON state, so that stable discharge can be performed in a low resistance state.

Further, according to the power supply system of the present invention, in the normal charging mode, when the output voltage of the external power supply 3 decreases, the power of each battery unit 2 is switched between the second switch 12 in the ON state and the second switch 12 in the ON state. A normal discharge mode in which power is supplied to the parallel line 8 via one switch 11 and power is supplied to the power supply line 5 of the external power supply 3 via the external connection switch 7 in the ON state. It is possible to discharge from a plurality of battery units 2.

According to the above configuration, when the output voltage of the external power supply decreases in the normal charging mode, the power of each battery unit is supplied via the second switch in the ON state, the first switch in the ON state, and the external connection switch in the ON state. Since the mode is shifted to the normal discharge mode supplied to the line, the output voltage of the external power supply is reduced without providing a mechanism for detecting a voltage drop of the commercial power supply or the external power supply, and without switching the connection part in the control part. It is possible to quickly supply power to the power supply line in the state.

Furthermore, according to the power supply system of the present invention, when the output voltage of the external power supply 3 is restored in the normal discharge mode, the external connection switch in which the power supplied from the power supply line 5 of the external power supply 3 is in the ON state. 7 is supplied to the parallel line 8 through the power supply line 7 and the power of the parallel line 8 is supplied to each battery unit 2 through the first switch 11 in the ON state and the second switch 12 in the ON state. The battery mode 2 can be charged by shifting to the charging mode.

According to the above configuration, when the output voltage of the external power supply is restored in the normal discharge mode, each battery is connected to the power supply line through the external connection switch in the ON state, the first switch in the ON state, and the second switch in the ON state. Since the mode is changed to the normal charging mode supplied to the unit, the output voltage of the external power supply is restored without providing a mechanism for detecting the voltage restoration of the commercial power supply or the external power supply, and without switching the connection part at the control part. The battery unit can be charged by supplying power quickly in the state.

Furthermore, according to the power supply system of the present invention, in the balance charging mode, when the voltage difference between the battery units 2 is greater than or equal to a predetermined second voltage difference, the external connection switch 7 sends a signal from the control unit 10. And the control unit 10 turns on the first switch 11 of each connection unit 9, turns off the second switch 12, and turns on the third switch 13, and the voltage difference between the battery units 2. It is possible to equalize the plurality of battery units 2 by shifting to an equalization mode for reducing the battery level.

With the above configuration, it is possible to eliminate voltage variations among a plurality of battery units connected in parallel. In particular, battery units having a large voltage difference can be quickly equalized. Thus, by providing the equalization mode and equalizing the voltage difference between the battery units in advance, it is possible to suppress variations in the state of charge.

Furthermore, according to the power supply system of the present invention, in the balance charging mode, when the difference between the voltage of the power supply line 5 and the voltage of each battery block 20 is equal to or less than a predetermined voltage difference, the external connection switch 7 is It is switched to OFF by a signal from the control unit 10, and the control unit 10 switches the first switch 11 of each connection unit 9 from OFF to ON, and the second switch 12 of each connection unit 9 from OFF to ON, After the third switch 13 of each connection unit 9 is switched from ON to OFF, the external connection switch 7 can be switched ON by a signal from the control unit 10 to shift to the normal charging mode.

With the above configuration, in the control to switch from the balance charge mode to the normal charge mode, the first switch of each connection part is turned from OFF to ON, the second switch is turned from OFF to ON, and the third switch is turned on when the external connection switch is turned off. Since switching from ON to OFF, in the step of sequentially switching a plurality of switches, only a part of the battery units is connected to the power supply line, and it is possible to reliably prevent a situation in which an overcurrent flows through the battery units. .

Further, according to the power supply system of the present invention, when the output voltage of the external power supply 3 is restored in the drive stop mode, the external connection switch 7 is controlled to be ON, and the control unit 10 is connected to each connection unit 9. The first switch 11 is turned off, the second switch 12 is turned off, and the third switch 13 is turned on to shift to the balance charging mode and charge each battery unit 2.

With the above configuration, the battery unit can be charged via the first rectifying element, and even if a voltage drop of the external power source occurs, discharge is prevented by turning off the first switch. Can be prevented, and a situation in which the voltage difference between the battery units increases due to the discharge can be avoided, and the battery units can be charged with the same voltage.

Furthermore, according to the power supply system of the present invention, the external power supply 3 can charge the battery unit 2 while switching the output voltage of the power supply circuit 4.

With the configuration described above, a plurality of battery units can be ideally charged by controlling the output voltage of the power supply circuit so that the charging voltage of the battery unit becomes the optimum voltage in the charged state of the battery unit.

Furthermore, according to the power supply system of the present invention, the first rectifying element 16 and / or the second rectifying element 17 can be diodes.

Furthermore, according to the power supply system of the present invention, the first switch 11 and / or the second switch 12 can be transistors.

Furthermore, according to the power supply system of the present invention, the first switch 11 and / or the second switch 12 are FETs, and the first rectifier 16 and / or the second rectifier 17 are parasitic elements built in the FET. It can be a diode.

With the above configuration, a rectifying action using a parasitic diode provided in advance in the FET can be achieved, and the system configuration can be simplified.

According to another power supply system of the present invention, a plurality of battery units 2 formed by connecting a plurality of battery cells 21 in series, and a connection unit 1 that connects the plurality of battery units 2 in parallel and outputs them to the outside. The connection unit 1 is connected to the power supply line 5 of the external power supply 3 that converts the power supplied from the commercial power supply 30 into a direct current and outputs it to the drive target device 40, and is supplied from the power supply line 5. The battery cell 21 of the battery unit 2 is charged with the generated power, and power is supplied from the battery unit 2 to the power supply line 5 in a state where the voltage output from the external power source 3 to the drive target device 40 is reduced. Like to do. The connection unit 1 includes a parallel line 8 that connects the plurality of battery units 2 in parallel, a connection unit 9 that connects each battery unit 2 to the parallel line 8, and a control that controls the connection state of the connection unit 9. The parallel line 8 is connected to the power supply line 5 of the external power source 3 via the external connection switch 7 that is turned off when the voltage of the power supply line 5 becomes a predetermined value or less. The connection portion 9 includes a series circuit of a first switch 11 and a second switch 12 connected in series between the parallel line 8 and the battery unit 2, and a current connected in parallel to the second switch 12. A sub-connection circuit 15 composed of a series circuit of a limiting resistor 14 and a third switch 13, and connected in parallel to the first switch 11, and arranged in a direction to energize the battery unit 2 from the parallel line 8. A first rectifying element 16 having an action, and a second rectifying element 17 connected in parallel with the second switch 12 and having a rectifying action in a direction of energizing the parallel line 8 from the battery unit 2. . In the power supply system, the control unit 10 precharges each battery unit 2 with the first switch 11 of each connection unit 9 turned off, the second switch 12 turned off, and the third switch 13 turned on. After the balance charging mode and the balance charging mode, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, turns off the third switch 13, and The normal charging mode for fully charging the battery unit 2 and when each battery unit 2 is fully charged, the control unit 10 turns on the first switch 11 of each connection unit 9 and turns off the second switch 12. In the full charge mode in which the charging of the battery unit 2 is stopped by turning off the third switch 13 and the full charge mode, the output voltage of the external power source 3 is Then, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, and turns off the third switch 13, and supplies power from each battery unit 2 to the external power supply 3. In the normal discharge mode for supplying power to the line 5 and in the normal discharge mode, when the voltage of the power supply line 5 becomes equal to or lower than the predetermined value, the external connection switch 7 is controlled to be OFF, In the discharge stop mode for stopping discharge and the discharge stop mode, when the cell voltage of the battery unit 2 becomes a predetermined value or less, the control unit 10 turns off the first switch 11 of each connection unit 9, A plurality of battery units are charged and discharged by switching between a driving stop mode in which the second switch 12 is turned off and the third switch 13 is turned off.

With the above configuration, a plurality of battery units connected in parallel can be charged while being equalized. In particular, in the balance charge mode, after precharging while equalizing the battery units with voltage difference, the full charge is performed in the normal charge mode. You can avoid situations that are exchanged between units. In addition, since each battery unit is precharged in the balance charge mode and then switched to the normal charge mode to fully charge, power supply to the drive target device becomes unstable by allocating a large amount of power to charge the battery unit. The situation can also be avoided, and hot standby is also possible in which the battery units are charged in parallel while the operation of the drive target device is continued.

Furthermore, according to another power supply system of the present invention, a plurality of battery units 2 formed by connecting a plurality of battery cells 21 in series, and a connection unit that connects the plurality of battery units 2 in parallel and outputs them to the outside. The connection unit 1 is connected to a power supply line 5 of an external power supply 3 that converts the power supplied from the commercial power supply 30 into a direct current and outputs it to the drive target device 40, and this power supply line 5 The battery cell 21 of the battery unit 2 is charged with the power supplied from the battery unit 2 and the power output from the battery unit 2 to the power supply line 5 is reduced while the voltage output from the external power supply 3 to the drive target device 40 is reduced. To supply. The connection unit 1 includes a parallel line 8 that connects the plurality of battery units 2 in parallel, a connection unit 9 that connects each battery unit 2 to the parallel line 8, and a control that controls the connection state of the connection unit 9. And the parallel line 8 is connected to the power supply line 5 of the external power source 3, and the connecting part 9 is connected in series between the parallel line 8 and the battery unit 2. A series circuit of the first switch 11 and the second switch 12, a sub-connection circuit 15 connected in parallel with the second switch 12, and comprising a series circuit of the current limiting resistor 14 and the third switch 13, and the first switch A first rectifying element 16 connected in parallel to the switch 11 and having a rectifying action in a direction of energizing the battery unit 2 from the parallel line 8; and connected in parallel to the second switch 12; and And a second rectifier element 17 having a rectification action from the pond unit 2 in the direction of energizing the parallel lines 8. In the power supply system, the control unit 10 precharges each battery unit 2 with the first switch 11 of each connection unit 9 turned off, the second switch 12 turned off, and the third switch 13 turned on. After the balance charging mode and the balance charging mode, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, turns off the third switch 13, and The normal charging mode for fully charging the battery unit 2 and when each battery unit 2 is fully charged, the control unit 10 turns on the first switch 11 of each connection unit 9 and turns off the second switch 12. In the full charge mode in which the charging of the battery unit 2 is stopped by turning off the third switch 13 and the full charge mode, the output voltage of the external power source 3 is Then, the control unit 10 turns on the first switch 11 of each connection unit 9, turns on the second switch 12, and turns off the third switch 13, and supplies power from each battery unit 2 to the external power supply 3. When the normal discharge mode for supplying power to the line 5 and the cell voltage of the battery unit 2 become a predetermined value or less, the control unit 10 turns off the first switch 11 of each connection unit 9 and the second switch 12. Is switched off and the third switch 13 is switched off to charge / discharge a plurality of battery units.

Furthermore, the charge / discharge control method of the power supply system of the present invention is connected to an external commercial power supply 30, converts the power supplied from the commercial power supply 30 and supplies it to the drive target device 40, and a plurality of A plurality of battery units 2 formed by connecting battery cells 21 in series; and a connection unit 1 for connecting the plurality of battery units 2 in parallel to connect to the external power source 3. Power is supplied to the unit 2 to charge the battery cell 21, and power is supplied from the battery unit 2 to the drive target device 40 while the voltage output from the external power source 3 to the drive target device 40 is reduced. Is a method for controlling charging / discharging of a power supply system configured to supply power. The external power supply 3 is connected to the power supply circuit 4 for converting alternating current supplied from the commercial power supply 30 into direct current of a predetermined output voltage that drives the drive target device 40, and to the output side of the power supply circuit 4, The power supply line 5 that supplies power to the drive target device 40, the connection line 6 that is connected to the power supply line 5 and connects the connection unit 1, and the power supply line 5 provided on the connection line 6 An external connection switch 7 is provided which is turned off when the voltage of the line 5 becomes a predetermined value or less. The connection unit 1 includes a parallel line 8 that connects the plurality of battery units 2 in parallel, a connection unit 9 that connects each battery unit 2 to the parallel line 8, and a control that controls the connection state of the connection unit 9. And the parallel line 8 is connected to the connection line 6 of the external power source 3, and the connection part 9 is connected in series between the parallel line 8 and the battery unit 2. A series circuit of the first switch 11 and the second switch 12, a sub-connection circuit 15 connected in parallel with the second switch 12, and comprising a series circuit of the current limiting resistor 14 and the third switch 13, and the first switch A first rectifying element 16 connected in parallel to the switch 11 and having a rectifying action in a direction of energizing the battery unit 2 from the parallel line 8; and connected in parallel to the second switch 12; and And a second rectifier element 17 having a rectification action from the pond unit 2 in the direction of energizing the parallel lines 8. Further, according to the charge / discharge control method of the power supply system, the control unit 10 turns off the first switch 11 of each connection unit 9, turns off the second switch 12, and turns on the third switch 13. 2 and precharging while equalizing each battery unit 2, the control unit 10 turns on the first switch 11 of each connection unit 9, and the second switch 12. ON, the third switch 13 is turned OFF, the battery unit 2 is fully charged, and when each battery unit 2 is fully charged, the control unit 10 causes the first switch 11 of each connection unit 9 to ON, the second switch 12 OFF, the third switch 13 OFF, and the charging of the battery unit 2 is stopped, and the output voltage of the external power supply 3 is Then, the control unit 10 turns on the first switch 11, turns on the second switch 12, and turns off the third switch 13 of each connection unit 9, and power from each battery unit 2 to the external power supply 3. In the state of supplying power to the supply line 5 and supplying power from each battery unit 2 to the power supply line 5, the external connection switch is turned off when the voltage of the power supply line 5 falls below the predetermined value. When the cell voltage of the battery unit 2 becomes a predetermined value or less in the state where the discharge from each battery unit 2 is stopped and the discharge from each battery unit 2 is stopped, the control unit 10 And charging / discharging a plurality of battery units 2 by turning off the first switch 11, turning off the second switch 12, and turning off the third switch 13 of each connection portion 9. That.

This makes it possible to charge a plurality of battery units connected in parallel while equalizing them. In particular, by precharging while equalizing battery units with voltage differences and then fully charging them, they can be fully charged while suppressing variations in the state of charge, avoiding the situation where power is transferred between battery units during discharge. it can. Also, in the process of precharging while equalizing, each battery unit is precharged and then switched to the normal charging process to fully charge the battery unit. A situation where the supply becomes unstable can be avoided, and a hot standby in which the battery units are charged in parallel while the operation of the drive target device is continued is also possible.

FIG. 1 is a block diagram showing a power supply system according to an embodiment of the present invention. FIG. 2 is a flowchart showing a charge / discharge process in the power supply system shown in FIG. FIG. 3 is a block diagram showing a control state in the balance charge mode of the power supply system shown in FIG. FIG. 4 is a block diagram showing a control state in the equalization mode of the power supply system shown in FIG. FIG. 5 is a diagram illustrating equalization in a state where a battery unit having a high voltage is connected to the connection unit. FIG. 6 is a diagram illustrating equalization in a state where a battery unit having a low voltage is connected to the connection unit. FIG. 7 is a block diagram showing a control state in the normal charge mode (normal discharge mode) of the power supply system shown in FIG. FIG. 8 is a block diagram showing a control state in the full charge mode (preliminary discharge mode) of the power supply system shown in FIG. FIG. 9 is a block diagram showing a control state in the recharge mode (preliminary discharge mode) of the power supply system shown in FIG. FIG. 10 is a block diagram showing a control state in the discharge stop mode of the power supply system shown in FIG. FIG. 11 is a flowchart showing a process in which the power supply system shown in FIG. 1 charges and discharges a plurality of battery units. FIG. 12 is a flowchart showing a process in which the power supply system shown in FIG. 1 charges and discharges a plurality of battery units.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a power supply system and a charge / discharge control method of the power supply system for embodying the technical idea of the present invention, and the present invention is a charge / discharge of the power supply system and the power supply system. The control method is not specified as follows. In addition, the member shown by the claim is not what specifies the member of embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

The power supply system of the present invention is a backup power supply having a large number of secondary batteries, and is installed in, for example, a mobile phone base station or a traffic light, and used as a power supply in an emergency such as a power failure. In a state where power is normally supplied from a commercial power supply, this power supply system converts AC power supplied from the commercial power supply into DC power of a predetermined voltage and supplies it to a load that is a drive target device. In addition, when the built-in secondary battery is charged and the output of the commercial power supply decreases in the event of an emergency such as a power failure, power is supplied from the built-in secondary battery to the load that is to be driven. Drive the target device.

The power supply system shown in FIG. 1 is connected to an external commercial power supply 30, converts the power supplied from the commercial power supply 30 and supplies it to the drive target device 40, and a plurality of batteries connected in series A plurality of battery units 2 having cells 21 and a connection unit 1 for connecting the plurality of battery units 2 in parallel and connecting to an external power source 3 are provided. This power supply system supplies the power output from the external power supply 3 to the drive target device 40 so that the drive target device 40 is in an operating state, and the battery cell 21 is supplied with power supplied from the external power supply 3 to each battery unit 2. Charge. Further, the power supply system drives the drive target device 40 by supplying power from the battery unit 2 to the drive target device 40 in a state where the voltage output from the external power supply 3 to the drive target device 40 falls below a predetermined value. .

In the illustrated power supply system, six battery units 2 are connected to a connection unit 1. Thus, the power supply system that connects the plurality of battery units 2 in parallel can increase the capacity of the entire power supply system and extend the time during which power can be supplied to the drive target device 40. Furthermore, the power supply system can replace the battery unit 2 connected to the connection unit 1 due to maintenance or failure, or increase or decrease the number according to the application. Therefore, the number of the plurality of battery units connected to the connection unit is not limited to 6 sets in the power supply system, and can be 2 to 5 sets or 7 sets or more.
(External power supply 3)
The external power supply 3 converts the alternating current supplied from the commercial power supply 30 into a direct current and outputs it, and supplies this direct-current power to the drive target device 40. An external power supply 3 shown in FIG. 1 is connected to a power supply circuit 4 that converts an alternating current supplied from a commercial power supply 30 into a direct current of a predetermined output voltage that drives the drive target device 40, and an output side of the power supply circuit 4. The power supply line 5 that supplies power to the external device to be driven 40, the connection line 6 connected to the power supply line 5 on the output side of the power supply circuit 4, and the external connection provided on the connection line 6 And a switch 7.

The power supply circuit 4 is a circuit that converts the alternating current of the commercial power supply 30 into a direct current of a predetermined voltage and outputs it. For example, an AC / DC converter can be used. The power supply circuit 4 that is an AC / DC converter converts, for example, the alternating current of the commercial power supply 30 of 100V to 250V into the direct current of 40V to 56V and outputs it. The output of the power supply circuit 4 is specified in consideration of the power for operating the drive target device 40. The power supply circuit 4 shown in the figure has an output voltage of 50 to 53 V and an output that can operate the drive target device 40. The power supply circuit 4 supplies power to the drive target device 40 via the power supply line 5 in a state where the commercial power supply 30 does not fail. Furthermore, the external power supply 3 shown in the figure includes a controller 31 that controls the output voltage of the power supply circuit 4. The controller 31 is connected to the connection unit 1 via the communication line 32 and controls the output voltage of the power supply circuit 4 according to a request signal input from the connection unit 1. This power supply system can ideally charge a plurality of battery units 2 by controlling the output voltage of the power supply circuit 4 so that the charging voltage of the battery unit 2 becomes an optimum voltage when the battery unit 2 is charged. However, the external power supply does not necessarily have to have a structure in which the output voltage of the external power supply can be adjusted by the controller. This external power supply outputs a constant voltage from the power supply circuit. As such a power supply circuit, a constant current (MAX current of about 0.5 to 1 C) / constant voltage (MAX 4.2 V / cell or so) that regulates a maximum current and a maximum voltage used for charging a lithium ion battery. ) Power supply circuit can be used.

The external power supply 3 in FIG. 1 is connected to the power supply line 5 connected to the drive target device 40 on the output side of the power supply circuit 4. Further, the external power source 3 branches the power supply line 5 and connects a connection line 6 on the output side of the power circuit 4, and the connection unit 1 is connected to the connection line 6. Further, the external power source 3 is provided with an external connection switch 7 on the connection line 6 in order to control the connection state between the power supply line 5 and the connection unit 1. As the external connection switch 7, a semiconductor switching element such as an FET or a transistor, a contactor, a relay, or the like can be used. The external connection switch 7 connects the power supply line 5 and the connection unit 1 in the ON state to allow charging current and discharge current, and disconnects the power supply line 5 and the connection unit 1 in the OFF state. Cut off charge and discharge currents.

The external connection switch 7 provided in the connection line 6 is controlled ON / OFF by a controller 31 built in the external power source 3. Although not shown, the controller 31 is supplied with operating power from the power supply line 5. For example, the controller 31 steps down the power supplied from the power supply line 5 using a DC / DC converter and is supplied with operating power. The controller 31 stops when the voltage of the power supply line 5 becomes a predetermined value or less and the operating power is not supplied. When the voltage of the power supply line 5 becomes equal to or less than a predetermined value (for example, 42 V) corresponding to the minimum operating voltage of the drive target device 40, the controller 31 stops and the external connection switch 7 is turned off. The controller 31 is driven by the power output from the power supply circuit 4 to the power supply line 5 in the operating state of the external power source 3, that is, in the state where the commercial power source 30 does not fail, and In a state in which the commercial power supply 30 fails, etc., the commercial power supply 30 is driven by power supplied from the connection unit 1 to the power supply line 5 via the connection line 6 and the external connection switch 7 in the ON state. Furthermore, the controller 31 controls ON / OFF of the external connection switch 7 based on various voltage data input from the connection unit 1 via the communication line 32.

The controller 31 holds the external connection switch 7 in the ON state when the voltage of each battery unit 2 input from the connection unit 1 is within a predetermined range and is normally charged / discharged. When the voltage becomes lower than the minimum voltage, the external connection switch 7 is turned off, and the connection unit 1 is disconnected from the power supply line 5 to prevent overdischarge of the battery unit 2. Furthermore, the controller 31 detects an abnormality from the battery information or the like of each battery unit 2 input from the connection unit 1, or when an abnormality signal is input from the connection unit 1, switches the external connection switch 7 to OFF. The connection unit 1 can also be disconnected from the power supply line 5. However, the controller can also switch on / off of the external connection switch based on a control signal input from the connection unit via the communication line. This controller is controlled by the connection unit to switch the external connection switch ON / OFF.

Here, in a non-operating state of the external power source 3, for example, a state in which the commercial power source 30 fails, etc., power is supplied from the connection unit 1 to the power supply line 5. The controller 31 is driven and the external connection switch 7 is kept ON. For this reason, the external connection switch 7 is not switched on until the operating state of the external power supply 3 is reached, that is, until the power failure of the commercial power supply 30 is restored. When the external power supply 3 is in an operating state and power is output to the power supply line 5, the controller 31 is driven, and the external connection switch 7 is switched on. However, the controller can also be driven by supplying operating power from the connection unit via the communication line in a state where power is not supplied from the power supply line. In addition, although not shown in the figure, the external power supply can be connected to a controller power supply line by connecting a spare power supply such as a capacitor, and the controller can be stopped by temporarily supplying power from the standby power supply even when the power supply line voltage drops. Can also be delayed.

The power supply line 5 is connected to both the output side of the power supply circuit 4 and the output side of the connection unit 1 when the external connection switch 7 is ON. Therefore, the output voltage of the power supply circuit 4 and the output voltage of the connection unit 1 are set substantially equal. In the power supply system having this structure, when the output voltage of the power supply circuit 4 is reduced due to a power failure, the power is supplied from the connection unit 1 to the power supply line 5 via the external connection switch 7 in the ON state, When power is supplied to 40 and the output voltage of the connection unit 1 decreases, power is supplied from the power supply line 5 to the connection unit 1 via the external connection switch 7 in the ON state. The plurality of battery units 2 connected to are charged. Therefore, this power supply system detects the voltage drop of the commercial power supply 30 or the external power supply 3 by turning on the external connection switch 7 and always connecting the output side of the connection unit 1 to the power supply line 5. Without providing a mechanism, in a state where the output voltage of the power supply circuit 4 decreases from the output side of the connection unit 1 or a state where the output voltage decreases below a predetermined value (for example, the minimum operating voltage of the device to be driven), power is quickly supplied. Electric power can be supplied to the supply line 5.

However, the power supply system can also include a mechanism for detecting that the output voltage of the power supply circuit has dropped due to a power failure of the commercial power supply or a failure of the power supply circuit. In this power supply system, the external connection switch was turned off during normal times except when the battery unit was charged, and the output voltage of the power supply circuit fell below the specified value due to a power failure of the commercial power supply or failure of the power supply circuit. Is detected, the external connection switch is turned on, and power can be supplied from the connection unit to the power supply line.
(Battery unit 2)
The battery unit 2 includes a battery block 20 formed by connecting a plurality of battery cells 21 in series, and a detection circuit 22 that detects the state of the battery cells 21 constituting the battery block 20. The battery block 20 preferably has a plurality of battery cells 21 connected in series and in parallel. A battery block 20 formed by connecting a plurality of battery cells 21 in series and in parallel can increase the charge / discharge current while increasing the output voltage. The battery block 20 has a plurality of battery cells 21 connected in series so that the output voltage of the battery unit 2 is substantially equal to the output voltage of the power supply circuit 4 of the external power supply 3. Since the output of the power supply circuit 4 is set to a voltage at which the drive target device 40 connected to the power supply line 5 can be operated, the output of the battery unit 2 is also set to this voltage. The output voltage of the battery unit 2 is 40V to 56V, for example, and is set to about 52V.

The battery cell 21 is a lithium ion battery or a nickel metal hydride battery. However, all the batteries which can be charged like a polymer battery and a nickel cadmium battery can be used for a battery cell. In the battery block 20 in which the battery cell 21 is a lithium ion battery, 13 battery cells 21 are connected in series so that the output voltage can be about 52V. In the battery block 20 in which the battery cell 21 is a nickel metal hydride battery, 43 to 45 battery cells 21 are connected in series, and the output voltage can be set to 51V to 54V. Furthermore, the battery block 20 can increase the current capacity by increasing the number of battery cells 21 connected in parallel. The battery block 20 adjusts the number of battery cells 21 connected in series and in parallel so that, for example, 2.5 kW of power can be output to the power supply line 5 continuously for 2 to 6 hours.

The detection circuit 22 detects the state of each battery cell 21 constituting the battery block 20 and transmits the detected battery information to the connection unit 1. The detection circuit 22 detects battery information such as the cell voltage of the battery cell 21, the output voltage of the battery block 20, the charge / discharge current flowing through the battery block 20, and the battery temperature at a predetermined sampling period, and digitally detects the detected battery information. The signal is converted into a signal and output to the connection unit 1.
(Connection unit 1)
The connection unit 1 connects a plurality of battery units 2 in parallel, controls charging and discharging of these battery units 2, and equalizes the plurality of battery units 2 connected in parallel. The connection unit 1 shown in FIG. 1 controls a parallel line 8 that connects a plurality of battery units 2 in parallel, a connection unit 9 that connects each battery unit 2 to the parallel line 8, and a connection state of each connection unit 9. And a control unit 10. The connection unit 1 controls the connection state of each connection unit 9 by the control unit 10 to control charging / discharging of the plurality of battery units 2 and equalizes the plurality of battery units 2 connected to the parallel line 8. To do.
(Parallel line 8)
The parallel line 8 is connected to the outputs of the plurality of battery units 2 and connects the plurality of battery units 2 in parallel. Furthermore, the parallel line 8 is connected to the connection line 6 of the external power supply 3. The parallel line 8 connected to the connection line 6 is connected to the power supply line 5 of the external power source 3 via the external connection switch 7 controlled to be turned ON / OFF by the controller 31. Therefore, the parallel line 8 is connected to the power supply line 5 when the external connection switch 7 is ON, and is disconnected from the power supply line 5 when the external connection switch 7 is OFF. The parallel line 8 connected to the power supply line 5 supplies the power output from the battery unit 2 to the power supply line 5, and supplies the power supplied from the power supply line 5 to the battery unit 2. The battery unit 2 is charged.

Furthermore, it is possible to equalize the plurality of battery units 2 connected in parallel, with the external connection switch 7 turned off and the parallel line 8 disconnected from the power supply line 5. The plurality of battery units 2 connected in parallel via the parallel line 8 while being disconnected from the power supply line 5 are charged and discharged by the voltage difference to be equalized. That is, in the battery unit 2 having a high voltage with respect to the parallel line 8, the parallel line 8 is discharged, and in the battery unit 2 having a low voltage with respect to the parallel line 8, the electric power supplied from the parallel line 8 is used. Charged and equalized.
(Connection 9)
The connection part 9 is arrange | positioned between each battery unit 2 and the parallel line 8, and is controlled by the control part 10, and specifies the connection state of each battery unit 2 and the parallel line 8. FIG. 1 is connected in parallel to the series circuit of the first switch 11 and the second switch 12 connected in series between the parallel line 8 and each battery unit 2, and the second switch 12. The first rectification which is connected in parallel with the first switch 11 and has a rectifying action in the direction in which the battery unit 2 is energized is connected in parallel with the first switch 11 and the sub-connection circuit 15 including a series circuit of the current limiting resistor 14 and the third switch 13. An element 16 and a second rectifying element 17 connected in parallel with the second switch 12 and having a rectifying action in a direction of energizing the parallel line 8 from the battery unit 2 are provided.

The first switch 11 and the second switch 12 are switches that connect the battery unit 2 to the parallel line 8 when the battery unit 2 is charged or discharged. The first switch 11 and the second switch 12 shown in the figure are connected in series with each other, and are connected between each battery unit 2 and the parallel line 8. The first switch 11 and the second switch 12 are switches that are controlled to be turned ON / OFF by the controller 10, and can be semiconductor switching elements, for example. The first switch 11 and the second switch 12 that are semiconductor switching elements may be FETs or transistors, for example. However, contactors and relays can also be used for the first switch and the second switch.

The sub-connection circuit 15 is connected in parallel to the second switch 12 and is configured by a series circuit of a current limiting resistor 14 and a third switch 13. The sub-connection circuit 15 allows a current that is passed from the parallel line 8 to the battery unit 2 in a state where the second switch 12 is turned off and the third switch 13 is turned on, that is, charging current, The charging current to be energized is limited by the current limiting resistor 14.

In a state where a plurality of battery units 2 connected to the parallel line 8 are charged, the current limiting resistor 14 charges while limiting an excessive current flowing from the parallel line 8 to the battery unit 2 to a small value. The power supply system that connects a plurality of battery units 2 in parallel needs to connect another new battery unit 2 to the parallel line 8 when replacing the battery unit 2 or increasing the number of battery units 2. . At this time, the voltage of the newly connected battery unit 2 is not necessarily the same as the voltage of the parallel line 8. The difference between the voltage of the battery unit 2 and the voltage of the parallel line 8 may cause a large current to flow through the battery unit 2 to be connected. The current limiting resistor 14 limits this current and suppresses an inrush current to the battery unit 2.

Furthermore, in a state where a plurality of battery units 2 are charged with power supplied from the external power supply 3, if the power supplied from the power supply line 5 to each battery unit 2 increases, the power supply line 5 supplies the drive target device 40. There is a possibility that the power to be supplied decreases and the drive target device 40 cannot be driven. Therefore, in a state in which the battery unit 2 is charged with the output of the external power source 3, each battery unit 2 is charged to a predetermined remaining capacity and the voltage of each battery unit 2 rises to a predetermined voltage. It is desirable to limit the charging current of 2 to suppress charging. Also in this case, by charging each battery unit 2 via the sub-connection circuit 15, a plurality of battery units 2 are charged while limiting the charging current flowing through each battery unit 2. The power supplied to the drive target device 40 is prevented from decreasing.

The current limiting resistor 14 can increase the electric resistance and reduce the current flowing through the battery unit 2. However, if the electric resistance of the current limiting resistor 14 is increased, the amount of heat generated by Joule heat increases, and the time for charging the battery unit 2 to a predetermined voltage or equalizing a plurality of battery units becomes longer. Therefore, the electric resistance of the current limiting resistor 14 is an electricity that can quickly equalize each battery unit 2 while quickly charging the voltages of the plurality of battery units 2 to a predetermined voltage, and can further reduce the amount of heat generated by energization. Set to resistance. The optimum value of the electric resistance of the current limiting resistor 14 varies depending on the voltage of the battery unit 2, but the voltage of the battery unit 2 is set to 52 V, for example, 1Ω to 10Ω, preferably 1Ω to 5Ω, more preferably 1Ω to 3Ω. The

The third switch 13 is a switch that is controlled ON / OFF by the control unit 10 and is a semiconductor switching element such as an FET or a transistor. However, relays and contactors can also be used for the third switch.

The first rectifying element 16 is connected in parallel with the first switch 11 and has a rectifying action in a direction in which the battery unit 2 is energized from the parallel line 8. The first rectifying element 16 shown in the drawing is a diode, and is connected in a direction allowing energization from the parallel line 8 to the battery unit 2, and allows a current to flow in the direction in which the battery unit 2 is charged.

Further, the second rectifying element 17 is connected in parallel with the second switch 12 and has a rectifying action in the direction of energizing the parallel line 8 from the battery unit 2. The second rectifying element 17 shown in the figure is a diode, and is connected in a direction allowing energization from the battery unit 2 to the parallel line 8, and allows a current discharged from the battery unit 2.

Here, in a structure in which the first switch 11 and the second switch 12 are FETs, such a rectifying element can be a parasitic diode built in the FET. This structure can simplify the system configuration by realizing a rectifying action using a parasitic diode provided in advance in the FET. When the third switch is an FET having a parasitic diode, the parasitic diode of the third switch and the second rectifying element are connected in the same direction.
(Control unit 10)
The control unit 10 controls ON / OFF of the first switch 11, the second switch 12, and the third switch 13 provided in each connection unit 9 to optimize the charging state and discharging state of the plurality of battery units 2. Control to the correct state. In particular, in the charged state, the plurality of battery units 2 are charged while being equalized. The control unit 10 controls each switch by outputting a control signal for controlling the semiconductor switching element to be turned on / off for the switch made of the semiconductor switching element. Also, for the switch made of the relay or the contactor, the energizing coil is energized. To switch each switch on and off.

The control unit 10 controls charging and discharging of each battery unit 2 to an optimal state based on the battery information input from the detection circuit 22 incorporated in each battery unit 2, and also controls the plurality of battery units 2. Equalize. The control unit 10 in the figure controls equalization and charging / discharging of the battery unit 2 based on the cell voltage of the battery cell 21 and the output voltage of the battery block 20 input from the detection circuit 22. For example, the battery cell 21 made of a lithium ion battery or a nickel metal hydride battery can determine the remaining battery capacity from the battery voltage. For this reason, equalization and charging / discharging of the battery unit 2 can be controlled while determining the remaining capacity of the battery from the cell battery and the output voltage. This method can equalize and charge / discharge a plurality of battery units 2 while determining the battery state in the simplest manner. However, the power supply system calculates the remaining capacity of each battery cell or battery block by the detection circuit from the integrated value of the charge / discharge current, and calculates the remaining capacity input from the detection circuit and a predetermined threshold value stored in the control unit. It is also possible to control equalization and charge / discharge of each battery unit while making comparisons with the control unit.

Further, the connection unit 1 shown in FIG. 1 includes a current detection unit 25, and the current detection unit 25 detects the current flowing from the parallel line 8 to the connection line 6 while charging / discharging a plurality of battery units 2. Is controlled to the optimum state. The current detection unit 25 shown in the figure detects a current detection resistor 26 connected in series between the parallel line 8 and the connection line 6 and a voltage across the current detection resistor 26 to detect the voltage across the parallel line 8 and the connection line. 6 and a detection circuit 27 for detecting a charging current and a discharging current flowing between the two. The current detection unit 25 detects a charge / discharge current value flowing between the parallel line 8 and the connection line 6 and inputs the current value to the control unit 10.

Furthermore, the control unit 10 is connected to the controller 31 of the external power supply 3 via the communication line 32 and transmits various data such as voltage data, battery information, and charge / discharge current values of each battery unit 2 to the controller 31. is doing. The controller 31 controls the external connection switch 7 to ON / OFF based on various data signals input from the control unit 10. Furthermore, the control part 10 can also control to transmit the abnormality signal to the controller 31 and to switch the external connection switch 7 to OFF when the abnormality of the battery unit 2 or the battery cell 21 is detected. Further, the control unit 10 can output a control signal for switching the external connection switch 7 ON / OFF, and can control the controller 31 with this control signal to control ON / OFF of the external connection switch 7. Further, in the state where the external power supply 3 that has been in the non-operating state due to a power failure or the like of the commercial power supply 30 is restored to the operating state, the control unit 10 puts the external power source 3 into the operating state by the return signal transmitted from the controller 31. It can detect that it has returned.

As shown in FIG. 2 below, the control unit 10 charges and discharges the plurality of battery units 2 while switching between the plurality of modes. 3 to 10, in each mode shown in FIG. 2, the controller 31 of the external power source 3 switches the external connection switch 7 to ON / OFF, and the control unit 10 includes the first switch 11 provided in each connection unit 9, The state which controls the 2nd switch 12 and the 3rd switch 13 to ON / OFF is shown. The control unit 10 determines the battery state of the plurality of battery units 2 from the battery information of each battery unit 2 input from the detection circuit 22 incorporated in each battery unit 2, for example, the output voltage or cell voltage, and externally. Various signals are transmitted to the controller 31 of the power supply 3 to control ON / OFF of the external connection switch 7, and ON / OFF of the first switch 11, the second switch 12, and the third switch 13 provided in each connection portion 9. By controlling OFF, the charge / discharge states of the plurality of battery units 2 are switched to the optimum mode.
[Battery unit detection mode]
In this step, the control unit 10 detects the connection state of the plurality of battery units 2. The control unit 10 recognizes the battery unit 2 connected to the connection unit 1 from the identification signal. The identification signal of each battery unit 2 is input from a detection circuit 22 built in each battery unit 2. From the identification signal input from the battery unit 2, the control unit 10 determines whether the number of connected battery units 2, a part of the battery units 2 is removed, or another battery unit 2 is newly connected. The connection state such as whether or not is determined.
[Balance charge mode]
In this step, the power supply system precharges the battery cells 21 of each battery unit 2 with power supplied from the power supply line 5 of the external power supply 3.

Furthermore, in this balanced charging mode, the external power supply 3 can suppress a large inrush current to the battery unit 2 by adjusting the output of the power supply circuit 4. The power supply circuit 4 is controlled by the controller 31 so that the output voltage that is the charging voltage of the battery unit 2 can be set to an optimum voltage. Here, the output voltage of the external power source 3 in the balance charging mode, that is, the first charging voltage for precharging the battery unit 2 is, for example, 48 V, or from the voltage of the battery block 20 of the battery unit 2 having the maximum output voltage. Also, the voltage can be increased by 0.5V.

As will be described later, when the power failure state continues after the discharge is stopped, the voltage of one of the battery cells 21 is less than a predetermined value (about 3 V / cell) due to power consumption in the internal circuit, self-discharge of the cell, and the like. Then, a signal is output from the detection circuit 22 of the battery cell 21 and input to the control unit 10. In this state, the control unit 10 turns off all of the first switch 11, the second switch 12, and the third switch 13, and between the control circuit 10 and the detection circuit 22 including the microcomputers of all the battery units 2. By stopping the drive power (drive voltage) 12V on the communication line 28, all the detection circuits 22 are shut down (stop driving). Thereby, each battery block 20 will be in the state isolate | separated from the parallel line 8, and a difference will arise in the voltage of each battery block 20 by the difference of the self discharge of the battery cell 21, etc.

In this balance charging mode, the power failure is resolved and the commercial power supply 30 is restored, and this is detected by the controller 31, and as shown in FIG. 3, the controller 31 turns on the external connection switch 7 to turn on the power supply line 5 The control unit 10 to which charging power can be supplied from the power supply line 5 to the connection unit 1 from the power supply line 5, the first switch 11 of each connection unit 9 is turned off, the second switch 12 is turned off, the third The switch 13 is turned on to precharge the battery cells 21 of each battery unit 2 with the power supplied from the power supply line 5 of the external power source 3. The drive circuit (drive voltage) 12V on the communication line 28 between the detection circuit 22 and the control unit 10 is supplied to drive the detection circuit 22.

Here, the voltage of the power supply circuit 4 is set to a predetermined voltage of about 48V and charged. When the difference between the predetermined voltage of about 48 V on the power supply line 5 and the voltage of each battery block 20 is all equal to or less than the predetermined voltage difference (for example, about 1.2 V), the balance charging mode is terminated. One switch 11 is turned ON, the second switch 12 is turned ON, the third switch 13 is turned OFF, the voltage of the power supply circuit 4 is set to a predetermined voltage (for example, about 52.6 V), and charging is performed as a normal charging mode. .

In the balance charging mode, as shown in FIG. 3, the first switch 11 and the second switch 12 of each connection portion 9 are turned OFF, but the power supplied from the external power supply 3 is the first rectifying element 16. The battery cell 21 is charged by being supplied to each battery unit 2 through the sub-connection circuit 15, that is, the series circuit of the third switch 13 and the current limiting resistor 14 in the ON state. Thereby, since each battery unit 2 is charged via the current limiting resistor 14 in a state of being connected in parallel, it is charged in a state where the voltages of the battery units 2 are equal.

As another example, the output voltages of all the battery units 2 are equal to or higher than the predetermined first set voltage while equalizing the voltage difference between the battery units 2 to be smaller than the predetermined first voltage difference. It can also be precharged. In this balanced charging mode, the voltage difference between all the battery units 2 is less than the first voltage difference, that is, the voltage difference between the battery unit 2 with the maximum output voltage and the battery unit 2 with the minimum output voltage is the first. Equalize until less than one voltage difference. Here, when the output voltage of the battery unit 2 is set to 52V, the control part 10 equalizes so that the voltage difference (Vd) between the battery units 2 may be less than 1.2V, for example.

In the above state, each battery unit 2 is charged in a state where the charging current is suppressed by the current limiting resistor 14. This avoids unstable power supply from the external power source 3 to the drive target device 40 without allocating a lot of power for charging each battery unit 2, and continues the operation of the drive target device 40. However, the battery unit 2 can be charged in parallel. Therefore, the first set voltage is a voltage that can stably supply the operating power from the external power source 3 to the drive target device 40 even when the battery unit 2 is charged without going through the sub-connection circuit 15, and preferably 40V to 50V, for example 42.5V. In the connection state shown in FIG. 3, even if the voltage of the power supply line 5 of the external power supply 3 decreases, the first switch 11 is turned off, so that the discharge from the battery unit 2 is prevented, and the battery It is possible to prevent the unit 2 from being overdischarged or from expanding the voltage difference between the battery units 2 due to the discharge.

As described above, since all the battery units 2 are charged with the same voltage in the balance charging mode, the battery unit 2 with a low output voltage is preferentially charged in a state where the battery unit 2 having a voltage difference is charged. The For this reason, it can charge, reducing the voltage difference of the some battery unit 2, ie, equalizing the battery unit 2 with a voltage difference. In addition, since the power supplied from the power supply line 5 of the external power supply 3 is supplied to each battery unit 2 via the first rectifying element 16, the third switch 13 in the ON state, and the current limiting resistor 14, the battery The unit 2 is precharged while the charging current is limited by the current limiting resistor 14. For this reason, even in the battery unit 2 having a low voltage, it is safely and stably charged and equalized while effectively preventing a large inrush current from flowing.

The balance charging mode described above is a step of precharging the battery units 2 while equalizing them when there is a predetermined voltage difference among the plurality of battery units 2 connected to the connection unit 1. When the battery is started, when some battery units are removed, when a new battery unit is connected, when charging starts after the battery unit is discharged, or when the battery unit 2 is charged for the first time, etc. Pre-charge while equalizing the battery units.
[Equalization mode]
Furthermore, in the balance charging mode, when the voltage difference between the battery units 2 is equal to or larger than the second voltage difference larger than the first voltage difference, the equalization mode is set as shown by the chain line arrow in FIG. It is also possible to equalize in a state where the connection unit 1 is disconnected from the power supply line 5 without shifting and precharging each battery unit 2.

In this step, the power supply system performs equalization to reduce the voltage difference between the battery units 2 so that the voltage difference between the battery units 2 is smaller than the second voltage difference. In this equalization mode, the battery units 2 can be equalized until the voltage difference between all the battery units 2 becomes less than the second voltage difference. Here, when the output voltage of the battery unit 2 is 52V and the first voltage difference is 1.2V, the second voltage difference is 1.2V or more, for example, 2.0V.

In this equalization mode, as shown in FIG. 4, the controller 31 turns off the external connection switch 7 with a signal from the control unit 10 to disconnect the connection unit 1 from the power supply line 5, and the control unit 10 The first switch 11 is turned on, the second switch 12 is turned off, and the third switch 13 is turned on to reduce the voltage difference between the battery units 2. In the connection state shown in FIG. 4, the first switch 11 of each connection portion 9 is turned on, the second switch 12 is turned off, and the third switch 13 is turned on, so that the battery unit has a higher output voltage than the other battery units 2. 4 is output to the parallel line 8 via the second rectifying element 17 and the first switch 11 in the ON state, as shown by a chain line arrow in FIG. Supplied. Moreover, in the battery unit 2 whose output voltage is lower than the other battery units 2, as shown by the arrows in FIG. 4, the power supplied from the battery unit 2 with the high output voltage is supplied to the first switch 11 in the ON state. The charging is performed while the charging current is limited by the current limiting resistor 14 by being supplied via the sub-connection circuit 15, that is, the series circuit of the third switch 13 in the ON state and the current limiting resistor 14. For this reason, even between the battery units 2 having a large voltage difference, while being effectively prevented from flowing a large inrush current, it is charged and discharged safely and stably and equalized.

In the above equalization mode, when there is a predetermined voltage difference among the plurality of battery units 2 connected to the connection unit 1, for example, at the time of starting the power system, When a part of the battery units is removed, when a new battery unit is connected, when charging is started after the battery unit is discharged, etc., the mode can be changed to equalize the plurality of battery units.

Here, FIG. 5 and FIG. 6 are examples in which a plurality of battery units 2 are equalized in the equalization mode, and show a state in which another battery unit 2 ′ is newly connected to the connection unit 1. . FIG. 5 shows equalization in a state where the battery unit 2 ′ whose output voltage is higher than that of the parallel line 8 of the connection unit 1 is connected. In this case, as indicated by an arrow in FIG. 5, the current output from the newly connected battery unit 2 ′ passes through the second rectifying element 17 and the first switch 11 in the ON state to the parallel line 8. It is energized and supplied to another battery unit 2 with a low output voltage. That is, the output of the newly connected battery unit 2 ′ is energized via the second rectifying element 17 without being energized to the current limiting resistor 14 of the connection portion 9 ′ to which the battery unit 2 ′ is connected. . For this reason, it is possible to reliably prevent the current output from the new battery unit 2 ′ from being supplied to the current limiting resistor 14 of the connection portion 9 ′ and generating heat due to Joule heat. As a result, the power of the newly connected battery unit 2 ′ is effectively used for another battery unit 2 without being wasted by the current limiting resistor 14 of the connection portion 9 ′. In particular, if there is a large voltage difference between the newly connected battery unit 2 ′ and the parallel line 8, a large current may flow from the battery unit 2 ′. As shown by, since the current is diverted to the plurality of other battery units 2, the amount of heat generated in each current limiting resistor 14 can be reduced by reducing the current flowing through each connection portion 9.

FIG. 6 shows equalization in a state where the battery unit 2 ′ whose output voltage is lower than that of the parallel line 8 of the connection unit 1 is connected. In this case, as shown by an arrow in FIG. 6, power is supplied from the other battery units 2 to the newly connected battery unit 2 ′ via the parallel line 8. The current output from the other battery unit 2 is energized to the parallel line 8 via the second rectifying element 17 of each connection portion 9 and the first switch 11 in the ON state, and the battery unit 2 having a low output voltage. Supplied to '. That is, the output of the other battery unit 2 is energized via the second rectifying element 17 without being energized to the current limiting resistor 14 of each connection part 9. For this reason, the current output from the other battery unit 2 is reliably prevented from being energized by the current limiting resistor 14 of each connecting portion 9 and generating heat due to Joule heat. Thereby, the electric power of the other battery unit 2 is effectively used for the newly connected battery unit 2 ′ without being wasted by the current limiting resistor 14 of the connection portion 9. In addition, since there is a voltage difference between the new battery unit 2 ′ and the parallel line 8, there is a possibility that a large current flows through the battery unit 2 ′. This current is caused by the current limiting resistor 14 of the connection portion 9 ′. As a result, a large inrush current to the battery unit 2 ′ is prevented. In particular, since the newly connected battery unit 2 'is normally charged to a certain remaining capacity, the voltage difference from other battery units 2 already connected to the connection unit 1 becomes abnormally large. The amount of heat generated by the current limiting resistor 14 can also be reduced.
[Normal charging mode]
When the balance charging mode is finished, in this process, the power supply system turns on the second switch 12 and turns off the third switch 13 of each connection section 9 and limits the power supplied from the external power supply 3 by the current limiting resistor 14. Without being performed, the battery cells 21 are fully charged by being supplied to each battery unit 2.

In this normal charging mode, as shown in FIG. 7, the controller 31 turns on the external connection switch 7 so that charging power can be supplied from the power supply line 5 to the connection unit 1. The first switch 11 is turned on, the second switch 12 is turned on, the third switch 13 is turned off, and the battery cells 21 of each battery unit 2 are charged with power supplied from the power supply line 5 of the external power supply 3. . In the connection state shown in FIG. 7, since the first switch 11 of each connection part 9 is turned on, the second switch 12 is turned on, and the third switch 13 is turned off, the power supplied from the external power source 3 is as shown in FIG. As indicated by the arrows, the battery cells 21 are charged by being supplied to each battery unit 2 in a low resistance state via the first switch 11 in the ON state and the second switch 12 in the ON state. For this reason, the battery unit 2 is ideally charged with the electric power supplied from the external power source 3 without suppressing the charging current. Moreover, since each battery unit 2 is charged by the balance charge mode which is a previous process, even in a state where a plurality of battery units 2 are charged, the voltage of the power supply line 5 is not reduced, that is, the external power source The battery unit 2 can be charged in parallel while avoiding unstable power supply from 3 to the drive target device 40 and continuing the operation of the drive target device 40.

In particular, in this normal charging mode, the external power supply 3 can adjust the output of the power supply circuit 4 in order to efficiently charge the plurality of battery units 2. The power supply circuit 4 is controlled by the controller 31 so that the output voltage that is the charging voltage of the battery unit 2 is an optimum voltage. Here, the output voltage of the external power source 3 in the normal charging mode, that is, the second charging voltage for charging the battery unit 2 can be set to, for example, 52.6V.

In the transition from the balance charge mode to the normal charge mode, preferably, the controller 31 switches off the external connection switch 7 once in response to a signal from the control unit 10, and the control unit 10 After the switch 11 is switched from OFF to ON, the second switch 12 of each connection section 9 is switched from OFF to ON, and the third switch 13 of each connection section 9 is switched from ON to OFF, the controller 31 switches the external connection switch 7. Can be switched on again. According to this control, the first switch 11 and the second switch 12 of each connection section 9 are sequentially switched from OFF to ON while the external connection switch 7 is OFF, so that only some battery units 2 are ON. Thus, it is possible to reliably prevent the overcurrent from flowing through the battery unit 2 by being connected to the power supply line 5 via the first switch 11 and the second switch 12.

Furthermore, in the normal charging mode, the control unit 10 can also perform overcharge protection of the battery unit 2 and the battery cell 21. For example, when the voltage of any one of the plurality of battery units 2 in the charged state becomes equal to or higher than the maximum unit voltage (for example, 53.3 V), the control unit 10 determines that the battery is overcharged, and Protect unit 2 by stopping charging. Moreover, when the voltage of any battery cell 21 exceeds the maximum cell voltage among the battery cells 21 configuring the battery unit 2 in the charged state, the control unit 10 determines that the battery cell 21 is overcharged. The battery unit 2 provided with is stopped and protected. For example, in the battery unit 2 formed by directly connecting 13 battery cells 21 composed of a plurality of lithium ion batteries, when the voltage of any one of the battery cells 21 is equal to or higher than the maximum cell voltage of 4.1 V, overcharge and Determination is made to stop and protect the battery unit 2 including the battery cell 21.

The normal charging mode is continued until the battery unit 2 is fully charged. The full charging of the battery unit 2 is determined as follows. For example, when the battery cell 21 constituting the battery unit 2 is a lithium ion battery, the charging current is reduced when the lithium ion battery is fully charged. Therefore, it is detected that the charging current is lower than a predetermined current value. Then, it is detected that each battery cell 21 is fully charged. In this power supply system, for example, the cell voltage (Vs) of one of the battery cells 21 is equal to or higher than a full charge determination voltage (for example, 3.9 V), and the charge current (Ic) is a full charge determination current (for example, 300 mA). ), It can be determined that the battery cell 21 is fully charged. That is, the control unit 10 for any one of the battery cells 21
Cell voltage (Vs) ≧ 3.9 V and 0 mA <charging current (Ic) <300 mA
Then, it can be determined that the battery cell 21 is fully charged. When any one of the battery cells 21 is determined to be fully charged, the battery unit 2 including the battery cell 21 is determined to be fully charged and charging is stopped. However, a battery unit including a battery cell that is prohibited from being charged or discharged for some reason is not subject to full charge, and any battery cell has a full charge determination voltage of 3.9 V or higher. Charging can be continued without determining that the battery unit that does not satisfy the condition is fully charged. And if each battery unit 2 satisfy | fills said full charge condition, the charge of the battery unit 2 will be stopped. That is, the second switch 12 is turned off to stop charging.
[Full charge mode]
In the normal charging mode, when the battery cells 21 of all the battery units 2 are fully charged, the power supply system switches the second switches 12 of all the connection portions 9 to OFF in this step to enter a standby state.

In this full charge mode, as shown in FIG. 8, the controller 31 turns on the external connection switch 7 to connect the power supply line 5 and the parallel line 8 of the connection unit 1. The first switch 11 of each connection part 9 is turned on, the second switch 12 is turned off, and the third switch 13 is turned off, so that the battery unit 2 can be discharged to the power supply line 5 in a standby state. This full charge mode is a standby state in which the external connection switch 7 that connects the parallel line 8 to the power supply line 5 of the external power supply 3 is kept in an ON state, and therefore a voltage drop of the commercial power supply 30 or the external power supply 3 is detected. Without providing a mechanism, power can be quickly supplied from the battery unit 2 to the power supply line 5 in a state where the output voltage of the power supply circuit 4 drops below a predetermined value.

Further, in the power supply system, when the full charge mode is continued for a long time, the remaining capacity of each battery cell 21 decreases due to self-discharge, circuit power consumption, and the like. Accordingly, in this full charge mode, the remaining capacity of one of the battery cells 21 is reduced by a predetermined rate (for example, 10%) from the fully charged state, or the cell voltage of any one of the battery cells 21 is reduced to the charge resumption voltage (for example, for example). In a lithium ion battery, charging can be resumed when it becomes 3.85 V or less.
[Recharge mode]
When it is determined that any battery unit 2 needs to be recharged in the full charge mode, the power supply system switches the third switch 13 of each connection unit 9 from OFF to ON in this step and starts recharging. To do.

In this recharge mode, as shown in FIG. 9, the controller 31 turns on the external connection switch 7 to connect the power supply line 5 and the parallel line 8 of the connection unit 1. The first switch 11 of each connection part 9 is turned on, the second switch 12 is turned off, the third switch 13 is turned on, and the power supplied from the external power source 3 is supplied to each battery unit 2 while being limited by the current limiting resistor 14. Then, the battery cell 21 is precharged. Thereby, it is effectively prevented that a large inrush current flows through the battery unit 2 to be recharged.

Further, in this recharge mode, the external power supply 3 can adjust the output of the power supply circuit 4 in order to precharge while suppressing the charging current to the battery unit 2. The power supply circuit 4 is controlled by the controller 31 so that the output voltage that is the charging voltage of the battery unit 2 is an optimum voltage. Here, the output voltage of the external power supply 3 in the recharging mode, that is, the third charging voltage for precharging the battery unit 2 can be set to 52.1 V, for example.

In the recharge mode, the control unit 10 determines whether or not the precharge of the battery unit 2 to be recharged is completed. The end of the precharge is determined, for example, by whether or not the cell voltages of all the battery cells 21 have become equal to or higher than a predetermined voltage (for example, 3.9 V), or whether the precharge time has passed a predetermined time Can be determined. When the precharge of the battery unit 2 is completed, the battery cell 21 of each battery unit 2 is fully charged by shifting to the normal charge mode.

Note that the above recharge mode can be omitted. In this case, if it is determined that any of the battery units needs to be recharged in the full charge mode, the battery can be recharged by shifting to the normal charge mode.
[Preliminary discharge mode]
When the output voltage of the power supply circuit 4 of the external power supply 3 drops due to a power failure or the like of the commercial power supply 30 in the full charge mode or the recharge mode, for example, the power supply system is below a predetermined value or below the output voltage of the connection unit 1 When the voltage drops to the preliminary discharge mode, power is supplied from the plurality of battery units 2 to the power supply line 5 of the external power source 3. In this preliminary discharge mode, as indicated by the chain line arrows in FIGS. 8 and 9, the electric power discharged from each battery unit 2 is supplied to the parallel line via the second rectifying element 17 and the first switch 11 in the ON state. 8 and the power of the parallel line 8 is supplied to the power supply line 5 of the external power supply 3 via the external connection switch 7 in the ON state.

Here, in the full charge mode, as shown in FIG. 8, the external connection switch 7 is turned on, the first switch 11 of each connection section 9 is turned on, the second switch 12 is turned off, and the third switch 13 is turned off. . In the recharge mode, as shown in FIG. 9, the external connection switch 7 is turned on, the first switch 11 of each connection part 9 is turned on, the second switch 12 is turned off, and the third switch 13 is turned off. For this reason, in these full charge mode or recharge mode, if the output voltage of the power supply circuit 4 falls below a predetermined value, the electric power of each battery unit 2 causes the second rectifying element 17 and the first switch 11 in the ON state to flow. To the parallel line 8 and to the power supply line 5 of the external power supply 3 via the external connection switch 7 in the ON state. Therefore, in a state where the output voltage of the power supply circuit 4 is lowered to a predetermined value or less without providing a mechanism for detecting a voltage drop of the commercial power supply 30 or the external power supply 3 and without switching the connection unit 9 by the control unit 10. Power can be supplied to the power supply line 5 promptly.

In the preliminary discharge mode, when the power supply from the battery unit 2 to the power supply line 5 is started, the current detection unit 25 detects the discharge current. As shown in FIG. 1, the current detection unit 25 detects a current flowing from the parallel line 8 to the connection line 6 and inputs the detected current value to the control unit 10. The control unit 10 detects that the power supply from the battery unit 2 to the power supply line 5 is started by receiving a signal indicating the current value of the discharge current from the current detection unit 25, and detects the second switch 12 is turned on to shift from the preliminary discharge mode to the normal discharge mode so that a large current flows. In this control, since the current detection unit 25 detects the discharge current, the control unit 10 switches the switch of each connection unit 9 to switch from the preliminary discharge mode to the normal discharge mode, so the discharge state of the battery unit 2 is confirmed. The normal discharge mode can be switched.

However, when the power supply system includes a mechanism for detecting a decrease in the output voltage of the power supply circuit, the preliminary discharge mode can be omitted. When the power supply system detects that the output voltage of the power supply circuit has dropped below a predetermined voltage due to a power failure of the commercial power supply or a failure of the power supply circuit in the full charge mode or recharge mode, the power supply system shifts to the normal discharge mode. Power can be supplied to the power supply line.
[Normal discharge mode]
In this step, the power supply system supplies power from the plurality of battery units 2 to the power supply line 5 by the control circuit 10 switching the second switch 12 of each connection unit 9 ON and the third switch 13 OFF. In this normal discharge mode, as indicated by the chain line arrow in FIG. 7, the power of each battery unit 2 is supplied to the parallel line 8 via the second switch 12 in the ON state and the first switch 11 in the ON state. At the same time, the power of the parallel line 8 is supplied to the power supply line 5 of the external power source 3 via the external connection switch 7 in the ON state, and discharged from the plurality of battery units 2. In the above normal discharge mode, each battery unit 2 is discharged through the second switch 12 in the ON state and the first switch 11 in the ON state, so that stable discharge can be performed in a low resistance state.

Furthermore, in the normal discharge mode, the control unit 10 can also perform overdischarge protection of the battery unit 2 and the battery cell 21. For example, when the voltage of any one of the plurality of battery units 2 in the discharged state becomes equal to or lower than the minimum unit voltage (for example, 39.0 V), the control unit 10 determines that the battery is overdischarged, and The discharge of the unit 2 is stopped and protected. In addition, when the voltage of any one of the battery cells 21 constituting the battery unit 2 in the discharged state becomes equal to or lower than the minimum cell voltage, the control unit 10 determines that the battery cell 21 is overdischarged. The discharge of the battery unit 2 comprising is stopped and protected. For example, in the battery unit 2 formed by directly connecting the battery cells 21 made of a plurality of lithium ion batteries, if the voltage of any one of the battery cells 21 is equal to or lower than the minimum cell voltage of 3.0 V, overdischarge occurs. It judges and stops discharge of battery unit 2 provided with this battery cell 21, and protects it.

Further, in the normal discharge mode, when the power failure of the commercial power supply 30 is restored, the output voltage of the power supply circuit 4 of the external power supply 3 becomes equal to or higher than a predetermined value, To charge as normal charging mode. The power supply system shifts to the normal charging mode, and the plurality of battery units 2 are charged with the power supplied from the power supply line 5. Here, in the normal discharge mode, as shown in FIG. 7, the external connection switch 7 is in the ON state, the first switch 11 of each connection section 9 is turned on, the second switch 12 is turned on, and the third switch 13 is turned off. It is said. Therefore, in this normal discharge mode, when the output voltage of the power supply circuit 4 returns to a predetermined value or more, the power supplied from the power supply line 5 of the external power supply 3 is in the ON state as shown by the arrow in FIG. While being supplied to the parallel line 8 via the external connection switch 7, it is supplied to each battery unit 2 via the first switch 11 in the ON state and the second switch 12 in the ON state. Therefore, without providing a mechanism for detecting a voltage increase of the commercial power supply 30 or the external power supply 3 and without switching the connection unit 9 by the control unit 10, the power supply circuit 4 can be quickly restored in the state where the output voltage is restored. Electric power can be supplied from the supply line 5 to the battery unit 2.

Furthermore, when the output voltage of the power supply circuit 4 of the external power supply 3 decreases due to a power failure or the like of the commercial power supply 30 in the normal charging mode described above, the power supply system shifts to the normal discharge mode and the plurality of battery units 2 receive external power supplies. 3 is supplied to the power supply line 5. Here, in the normal charging mode, as shown in FIG. 7, the external connection switch 7 is in the ON state, the first switch 11 of each connection section 9 is turned on, the second switch 12 is turned on, and the third switch 13 is turned off. It is said. Therefore, in this normal charging mode, when the output voltage of the power supply circuit 4 of the external power supply 3 decreases, the power of each battery unit 2 is switched to the ON state of the second switch 12 as shown by the chain line arrow in FIG. And supplied to the parallel line 8 through the first switch 11 in the ON state and supplied to the power supply line 5 of the external power source 3 through the external connection switch 7 in the ON state. Therefore, without providing a mechanism for detecting a voltage drop of the commercial power supply 30 or the external power supply 3, and without switching the connection unit 9 by the control unit 10, the battery unit can be quickly operated in a state where the output voltage of the power supply circuit 4 is lowered. 2 can supply power to the power supply line 5.
[Discharge stop mode]
In the normal discharge mode, when the battery unit 2 is discharged and becomes equal to or lower than the discharge stop voltage, the power supply system shifts to the discharge stop mode and stops the discharge of the battery unit 2 in this step. In this discharge stop mode, when the voltage of the power supply line 5 becomes a discharge stop voltage of a predetermined value (for example, 42 V) corresponding to the lowest operating voltage of the drive target device 40, the controller 31 is externally connected as shown in FIG. The connection switch 7 is turned off to stop the discharge from the battery unit 2. If the power failure is resolved before the voltage of any battery cell 21 drops to a predetermined value (about 3 V / cell), the controller 31 switches the external connection switch 7 to ON and enters the normal charging mode. Transition.

Further, in the discharge stop mode, the controller 31 can switch the external connection switch 7 to OFF based on a signal from the control unit 10. In this state, the parallel line 8 of the connection unit 1 is disconnected from the power supply line 5 and the power supply from the battery unit 2 to the power supply line 5 is stopped.
[Drive stop mode]
After the discharge from the battery unit 2 is stopped in the discharge stop mode, if the power failure state continues further, the voltage of any one of the battery cells 21 becomes a predetermined value due to power consumption in the internal circuit, cell self-discharge, etc. When the voltage is less than (approximately 3 V / cell), a signal is output from the detection circuit 22 of the battery cell 21 and input to the control unit 10. In this state, as shown in FIG. 1, the control unit 10 turns off the first switch 11, the second switch 12, and the third switch 13, and further includes a detection circuit including microcomputers and the like of all the battery units 2. All the detection circuits 22 are shut down (driving stopped) by stopping the driving power (driving voltage) 12 V on the communication line 28 between the control unit 10 and the control unit 10. Thereby, each battery block 20 will be in the state isolate | separated from the parallel line 8, and a difference will arise in the voltage of each battery block 20 by the difference of the self discharge of the battery cell 21, etc.

Further, in the drive stop mode, when the power failure of the commercial power supply 30 is restored and the output voltage of the power supply circuit of the external power supply 3 returns to a predetermined value or more, the power supply system shifts to the balance charge mode and charges the battery unit 2. Start. When the output voltage of the power supply circuit 4 of the external power supply 3 returns to a predetermined value or higher, power is supplied from the power supply line 5 to the control unit 10, the control unit 10 is activated, and the first switch 11, the second switch 12, And the 3rd switch 13 operate | moves and it transfers to balance charge mode.

In the balance charge mode, as described above, the plurality of battery units 2 are precharged while being equalized. Here, when the drive stop mode is continued and time elapses, the voltage of each battery unit 2 is lowered, and the voltage of each battery unit 2 may vary. Even in this case, the dispersion is eliminated by shifting to the balance charge mode and precharging while equalizing.

Furthermore, the control unit 10 of the connection unit 1 can also detect and protect the overcurrent of the current flowing through each battery unit 2. The control unit 10 detects a detection value of a charging current and a discharging current flowing through each battery unit 2 from a signal input from a detection circuit 22 built in each battery unit 2 when the battery unit 2 is charged or discharged. To do. When the charge / discharge current value input from each battery unit 2 exceeds a predetermined upper limit current value over a predetermined detection time, the control unit 10 determines that the current is overcurrent and stops charging / discharging the battery unit 2. Protect. Here, the upper limit current value at which the control unit 10 determines each battery unit 2 as an overcurrent can be, for example, 27 A to 33 A, and the detection time can be 0.5 seconds to 1.5 seconds. The control unit 10 turns off all the switches of the connection unit 9 connected to the battery unit 2 in which the overcurrent is detected, and stops charging / discharging of the battery unit 2.

Furthermore, the control unit 10 of the connection unit 1 can detect and protect the overcurrent of the current flowing through the parallel line 8. The connection unit 1 detects a charging current and a discharging current flowing in the parallel line 8 with the current detection unit 25 in the charging state and discharging state of the battery unit 2. When the current value detected by the current detection unit 25 exceeds a predetermined upper limit current value over a predetermined detection time, the control unit 10 determines that it is an overcurrent and stops charging and discharging all the battery units 2 to protect them. . Here, the upper limit current value for determining the overcurrent of the current flowing through the parallel line 8 by the control unit 10 may be, for example, 108A to 132A, and the detection time may be 0.25 seconds to 0.75 seconds. When the control unit 10 detects an overcurrent in the parallel line 8, it transmits an abnormal signal to the controller 31 via the communication line 32, and the controller 31 switches the external connection switch 7 to OFF to charge / discharge all the battery units 2. To stop.

Furthermore, the control unit 10 of the connection unit 1 can also control the charge / discharge state of the battery unit 2 based on the battery temperature detected by the detection circuit 22 of the battery unit 2. For example, when the battery temperature of any one of the battery units 2 is in an abnormal temperature range, the control unit 10 cuts off the connection unit 9 connected to the battery unit 2 and stops charging / discharging of the battery unit 2. .

The above power supply system charges the plurality of battery units 2 with the power supplied from the external power supply 3 and the output voltage of the external power supply 3 drops below a predetermined value in the following flowcharts shown in FIGS. 11 and 12. In the state, electric power is supplied to the power supply line 5 by discharging from the plurality of battery units 2.
[Step of n = 1]
In this step, the control unit 10 detects the connection state of the plurality of battery units 2 from the identification signal input from the detection circuit 22 of each battery unit 2. The control unit 10 removes the number of connected battery units 2, a part of the battery units 2 from the identification signal input from each battery unit 2, or newly connects another battery unit 2. The connection state such as whether or not has been determined. Furthermore, the control unit 10 determines an allowable maximum current value and the like based on the connection state of the plurality of battery units 2.
[Step n = 2] (Balanced charging mode)
In this step, the controller 31 and the control unit 10 precharge the plurality of battery units 2 while equalizing the plurality of battery units 2 by controlling ON / OFF of each switch as follows. (See Figure 3)
Furthermore, in this balance charge mode, the controller 31 controls the output voltage of the power supply circuit 4 to the first charge voltage. Here, the first charging voltage can be set to 48V, for example, or can be set to a voltage (Vmax + 0.5V) larger by 0.5V than the maximum voltage Vmax of the battery unit having the highest output voltage.

External connection switch ON
First switch ………… OFF
Second switch ………… OFF
3rd switch ………… ON
[Step n = 3]
In this step, the control unit 10 determines whether or not the difference between the voltage of the power supply line 5 and the voltage of each battery block 20 is smaller than a predetermined voltage difference (for example, about 1.2 V). When the difference between the voltage of the power supply line 5 and the voltage of each battery block 20 is 1.2 V or more, the process returns to the step of n = 2 and the balance charge mode is continued. When the difference between the voltage of the power supply line 5 and the voltage of each battery block 20 is less than 1.2 V, the process proceeds to the step of n = 4 and shifts to the normal charge mode.
[Step n = 4] (Normal charge mode)
In this step, the controller 31 and the control unit 10 fully turn on the plurality of battery units 2 by controlling ON / OFF of each switch as follows. (See Figure 7)
Further, in this normal charging mode, the controller 31 controls the output voltage of the power supply circuit 4 to the second charging voltage. Here, the second charging voltage can be set to, for example, 52.6V.

External connection switch ON
First switch ………… ON
Second switch ………… ON
Third switch ………… OFF
[Step n = 5]
In the normal charging mode, when the output voltage of the external power supply 3 falls below the set value due to a power failure or the like of the commercial power supply 30, the process proceeds to the step of n = 15 and shifts to the normal discharge mode. 3 is supplied to the power supply line 5.
[Step n = 6]
In this step, the control unit 10 determines whether any battery unit 2 is fully charged. Until the battery unit 2 is fully charged, the normal charge mode is continued by returning to the step of n = 4. When any one of the battery units 2 is fully charged, the process proceeds to step n = 7 and shifts to the full charge mode.
[Step n = 7] (Full charge mode)
In this step, the controller 31 and the control unit 10 control the ON / OFF of each switch as follows to enter a standby state. (See Figure 8)
External connection switch ON
First switch ………… ON
Second switch ………… OFF
Third switch ………… OFF
[Step n = 8]
In the full charge mode, when the output voltage of the external power supply 3 falls below the set value due to a power failure or the like of the commercial power supply 30, the process proceeds to step n = 13 to enter the preliminary discharge mode, and the plurality of battery units 2 are connected to the external power supply. 3 is supplied to the power supply line 5.
[Step n = 9]
In this step, the control unit 10 determines whether or not the remaining capacity of the battery unit 2 in the standby state is reduced and recharging is necessary. When the remaining capacity of any one of the battery cells 21 decreases by a predetermined rate (for example, 10%) from the fully charged state, or when the cell voltage of any one of the battery cells 21 becomes equal to or lower than the charge restart voltage (for example, 3.85 V). , N = 10 and recharge is started.
[Step n = 10] (Recharge mode)
In this step, the controller 31 and the control unit 10 precharge a plurality of battery units 2 by controlling ON / OFF of each switch as follows. (See Figure 9)
Further, in this recharging mode, the controller 31 controls the output voltage of the power supply circuit 4 to the third charging voltage. Here, the third charging voltage is set lower than the second charging voltage, and can be set to, for example, 52.1V.

External connection switch ON
First switch ………… ON
Second switch ………… OFF
3rd switch ………… ON
Note that the recharge mode can be omitted. In this case, when it is determined that recharging is necessary, the recharging can be performed by shifting to the normal charging mode.
[Step n = 11]
In the recharge mode, when the output voltage of the external power supply 3 drops below the set value due to a power failure or the like of the commercial power supply 30, the process proceeds to step n = 13 to enter the preliminary discharge mode, and the plurality of battery units 2 3 is supplied to the power supply line 5.
[Step n = 12]
In this step, the control unit 10 determines whether or not the precharge in the recharge mode is finished. Here, the end of the precharge is determined based on whether or not the cell voltages of all the battery cells 21 have become equal to or higher than a predetermined voltage (for example, 3.9 V), or whether the precharge time has passed a predetermined time It can be judged by how. Until the precharge is completed, the process returns to the step of n = 10 and the recharge mode is continued. When the precharge is completed, the process proceeds to the step of n = 4 and shifts to the normal charge mode.
[Step n = 13] (Preliminary discharge mode)
In this step, each switch is maintained ON / OFF as follows, and supplies power from the plurality of battery units 2 to the power supply line 5 of the external power supply 3. (See Figs. 8 and 9)
External connection switch ON
First switch ………… ON
Second switch ………… OFF
Third switch …… ON / OFF
In the preliminary discharge mode, as indicated by the chain arrows in FIGS. 8 and 9, the electric power discharged from each battery unit 2 is supplied to the parallel line 8 via the second rectifying element 17 and the first switch 11 in the ON state. And the power of the parallel line 8 is supplied to the power supply line 5 of the external power supply 3 through the external connection switch 7 in the ON state. Thereby, when the output voltage of the power supply circuit 4 decreases due to a power failure or the like, power supply from the battery unit 2 to the power supply line 5 is started immediately.

However, when the power supply system includes a mechanism for detecting a decrease in the output voltage of the power supply circuit, the preliminary discharge mode can be omitted. When this power supply system detects that the output voltage of the power supply circuit has dropped below a predetermined value due to a power failure of the commercial power supply or a failure of the power supply circuit in the full charge mode or the recharge mode, the following control of n = 15 , The power can be supplied to the power supply line by shifting to the normal discharge mode.
[Step n = 14]
In this step, it is determined whether or not the discharge current flowing from the parallel line 8 to the connection line 6 is detected by the current detection unit 25. When the discharge current to the connection line 6 is detected, the process proceeds to the step of n = 15 and the normal discharge mode is entered.
[Step n = 15] (Normal discharge mode)
In this step, the controller 31 and the control unit 10 continue the discharge state by controlling ON / OFF of each switch as follows. (See Figure 7)
External connection switch ON
First switch ………… ON
Second switch ………… ON
Third switch ………… OFF
In the normal discharge mode, the electric power discharged from each battery unit 2 is supplied to the parallel line 8 via the second switch 12 in the ON state and the first switch 11 in the ON state, as shown by the chain arrows in FIG. And the power of the parallel line 8 is supplied to the power supply line 5 of the external power supply 3 through the external connection switch 7 in the ON state.
[Step n = 16]
In the normal discharge mode, when the power failure of the commercial power supply 30 is restored and the output voltage of the external power supply 3 returns to a predetermined value or more, the process jumps to the step of n = 4, shifts to the normal charge mode, and charges the battery unit 2 To start.
[Step n = 17]
In this step, the control unit 10 determines whether or not the output voltages (Vy) of all the battery units 2 have become equal to or lower than the discharge stop voltage. This discharge stop voltage is a voltage corresponding to the minimum operating voltage of the drive target device 40 and is set to 42 V, for example. When the output voltages of all the battery units 2 are larger than the discharge stop voltage, the process returns to the step of n = 15 and the normal charge mode is continued. When the output voltage of any one of the battery units 2 becomes equal to or lower than the discharge stop voltage, the process proceeds to step n = 18 and shifts to the discharge stop mode.
[Step n = 18] (Discharge stop mode)
When the voltage of the power supply line 5 becomes equal to or lower than a discharge stop voltage (for example, 42 V), which is a predetermined value corresponding to the lowest operating voltage of the drive target device 40, the controller 31 switches the external connection switch 7 to OFF. In this state, the parallel line 8 is disconnected from the power supply line 5 and the power supply from the battery unit 2 to the power supply line 5 is stopped. (See Figure 10)
[Step n = 19]
In the discharge stop mode, when the power failure of the commercial power supply 30 is restored and the output voltage of the external power supply 3 returns to a predetermined value or more, the process jumps to the step of n = 4, shifts to the normal charge mode, and charges the battery unit 2 To start.
[Step n = 20]
In this step, the control unit 10 determines whether or not the voltage of any battery cell 21 has decreased to a predetermined value (about 3 V / cell). When the voltage of all the battery cells 21 is larger than a predetermined value (about 3V / cell), it returns to the step of n = 18 and continues discharge stop mode. When the voltage of any one of the battery cells 21 becomes a predetermined value (about 3 V / cell) or less, the process proceeds to a step of n = 21 and shifts to the drive stop mode.
[Step n = 21] (Drive stop mode)
In this step, the control unit 10 turns off all the switches so that all the battery units 2 are disconnected from the parallel line 8. (See Figure 1)
First switch ………… OFF
Second switch ………… OFF
Third switch ………… OFF
Further, the control circuit 10 stops the driving power (driving voltage) 12V put on the communication line 28 between the battery unit 2 and the detection circuit 22 composed of a microcomputer or the like, and shuts down (drives) all the detection circuits 22. Stop).
[Step n = 22]
In the drive stop mode, when the power failure of the commercial power supply 30 is restored and the output voltage of the external power supply 3 returns to a predetermined value or more, the operation jumps to the step of n = 2, shifts to the balance charge mode, and charges the battery unit 2 To start. In the state where the voltage of the power supply line 5 of the external power supply 3 does not return to the set value or more, the process returns to the step of n = 21 and the drive stop mode is continued.

Although not described in the above flowchart, in each mode, when it is detected that one of the battery units 2 is removed from the connection unit 1 or a new battery unit 2 is connected to the connection unit 1, Returning to the step of n = 1, it can restart from recognition of the connection state of the battery unit 2. Thereby, the reliability at the time of detachment | attachment of a battery unit can be improved, enabling the removal | desorption of the battery unit in a hot standby state.

The power supply system according to the present invention can be suitably used as a backup power supply for supplying power to mobile phone base stations, traffic lights, etc., when a commercial power supply fails. In particular, it is suitable for use as a power supply system that can connect multiple battery units with a large number of battery cells in parallel to increase the output while charging with the power supplied from the commercial power supply, and discharge when the output of the commercial power supply decreases. it can.

DESCRIPTION OF SYMBOLS 1 ... Connection unit 2 ... Battery unit 2 '... Battery unit 3 ... External power supply 4 ... Power supply circuit 5 ... Power supply line 6 ... Connection line 7 ... External connection switch 8 ... Parallel line 9 ... Connection part 9' ... Connection part 10 ... Control unit 11 ... first switch 12 ... second switch 13 ... third switch 14 ... current limiting resistor 15 ... sub-connection circuit 16 ... first rectifier 17 ... second rectifier 20 ... battery block 21 ... battery cell 22 ... detection Circuit 25 ... Current detection unit 26 ... Current detection resistor 27 ... Detection circuit 28 ... Communication line 30 ... Commercial power supply 31 ... Controller 32 ... Communication line 40 ... Drive target device

Claims

An external power source connected to an external commercial power source and converting the power supplied from the commercial power source to supply to the drive target device;
A plurality of battery units comprising a plurality of battery cells connected in series;
A connection unit for connecting the plurality of battery units in parallel and connecting to the external power source,
Power is supplied from the external power source to each battery unit to charge the battery cell, and power is supplied from the battery unit to the drive target device in a state where the voltage output from the external power source to the drive target device is reduced. A power supply system configured to supply,
The external power source is
A power supply circuit that converts alternating current supplied from a commercial power source into direct current of a predetermined output voltage that drives the drive target device;
A power supply line connected to the output side of the power supply circuit for supplying power to an external drive target device;
A connection line connected to the power supply line and connecting the connection unit;
An external connection switch provided on the connection line and turned off when the voltage of the power supply line is a predetermined value or less;
With
The connection unit is
A parallel line connecting the plurality of battery units in parallel;
A connecting portion for connecting each battery unit to the parallel line;
A control unit for controlling a connection state of the connection unit;
With
The parallel line is connected to a connection line of the external power source,
The connecting portion is
A series circuit of a first switch and a second switch connected in series between the parallel line and each battery unit;
A sub-connection circuit composed of a series circuit of a current limiting resistor and a third switch connected in parallel with the second switch;
A first rectifying element connected in parallel with the first switch and having a rectifying action in a direction of energizing the battery unit from the parallel line;
A second rectifying element connected in parallel with the second switch and having a rectifying action in a direction of energizing the parallel line from the battery unit;
The control unit turns off the first switch of each connection unit, turns off the second switch, and turns on the third switch, and precharges the battery units while equalizing each battery unit. Thereafter, the control unit turns on the first switch of each connection unit, turns on the second switch, turns off the third switch, and makes the battery unit fully charged, and
When each battery unit is fully charged, the control unit turns on the first switch, turns off the second switch, and turns off the third switch of each connection unit to stop charging the battery unit. Charging mode,
In the full charge mode, when the output voltage of the external power supply decreases, the control unit turns on the first switch, turns on the second switch, and turns off the third switch in each connection unit. A normal discharge mode for supplying power to the power supply line of the external power source from
In the normal discharge mode, when the voltage of the power supply line becomes equal to or lower than the predetermined value, the external connection switch is controlled to be OFF, and in the discharge stop mode in which the discharge from each battery unit is stopped, and in the discharge stop mode, When the cell voltage of the battery unit falls below a predetermined value, the control unit switches between a drive stop mode in which the first switch of each connection unit is turned off, the second switch is turned off, and the third switch is turned off. And charging / discharging a plurality of battery units.
The power supply system according to claim 1,
In the full charge mode, when the remaining capacity of any battery cell of the battery unit is decreased by a predetermined rate from the fully charged state, or when the cell voltage of any battery cell becomes equal to or lower than the charge restart voltage, the control unit However, when the first switch of each connection part is turned on, the second switch is turned off, and the third switch is turned on, the battery unit is recharged by entering a recharge mode in which each battery unit is precharged. Power supply system characterized by
The power supply system according to claim 1 or 2,
In the full charge mode or the recharge mode, when the output voltage of the external power supply decreases,
The power of each battery unit is supplied to the parallel line via the second switch and the first switch in the ON state, and the power of the parallel line is supplied to the external via the external connection switch in the ON state. A power supply system that discharges from a plurality of battery units in a preliminary discharge mode supplied to a power supply line of a power supply.
The power supply system according to claim 3,
The connection unit includes a current detection unit that detects an energization state to the connection line of the external power source,
In the preliminary discharge mode, when the current detection unit detects a discharge current to the connection line,
The control unit turns on the first switch of each connection unit, turns on the second switch, turns off the third switch, and the power of each battery unit is the second switch in the ON state and the first switch in the ON state. A plurality of batteries that are supplied to the parallel line through a switch and that are shifted to a normal discharge mode in which the power of the parallel line is supplied to the power supply line of the external power source through the external connection switch in an ON state A power supply system that discharges from a unit.
The power supply system according to any one of claims 1 to 4,
In the normal charging mode, when the output voltage of the external power supply decreases,
The power of each battery unit is supplied to the parallel line through the second switch in the ON state and the first switch in the ON state, and the power of the parallel line is supplied through the external connection switch in the ON state. A power supply system that shifts to a normal discharge mode supplied to a power supply line of the external power supply and discharges from a plurality of battery units.
The power supply system according to any one of claims 1 to 5,
In the normal discharge mode, when the output voltage of the external power supply returns,
The power supplied from the power supply line of the external power supply is supplied to the parallel line via the external connection switch in the ON state, and the power of the parallel line is in the ON state and the first switch in the ON state. A power supply system that shifts to a normal charge mode supplied to each battery unit via a second switch and charges a plurality of battery units.
The power supply system according to any one of claims 1 to 6,
In the balance charging mode, when the voltage difference between the battery units is equal to or greater than a predetermined second voltage difference,
The external connection switch is controlled to be turned off by a signal from the control unit, and the control unit turns on the first switch, turns off the second switch, and turns on the third switch in each connection unit. A power supply system that shifts to an equalization mode for reducing a voltage difference between units to equalize a plurality of battery units.
The power supply system according to any one of claims 1 to 7,
In the balance charging mode, when the difference between the voltage of the power supply line and the voltage of each battery block is equal to or less than a predetermined voltage difference, the external connection switch is turned OFF by a signal from the control unit, and the control unit The first connection switch of each connection unit is switched from OFF to ON, the second switch of each connection unit is switched from OFF to ON, the third switch of each connection unit is switched from ON to OFF, and then the external connection switch Is switched to ON by a signal from the control unit and shifts to the normal charging mode.
The power supply system according to any one of claims 1 to 8,
In the drive stop mode, when the output voltage of the external power supply returns,
The external connection switch is controlled to be ON, and the control unit turns off the first switch of each connection unit, turns off the second switch, and turns on the third switch, and shifts to the balance charging mode. A power supply system characterized by charging a unit.
The power supply system according to any one of claims 1 to 9,
The power supply system, wherein the external power supply charges the battery unit while switching an output voltage of the power supply circuit.
The power supply system according to any one of claims 1 to 10,
The first rectifying element and / or the second rectifying element is a diode.
The power supply system according to any one of claims 1 to 11,
The power supply system, wherein the first switch and / or the second switch is a transistor.
The power supply system according to any one of claims 1 to 12,
The first switch and / or the second switch is a FET;
The power supply system, wherein the first rectifier element and / or the second rectifier element is a parasitic diode built in the FET.
A plurality of battery units comprising a plurality of battery cells connected in series;
A connection unit for connecting the plurality of battery units in parallel and outputting to the outside,
The connection unit is connected to a power supply line of an external power source that converts power supplied from a commercial power source into direct current and outputs it to a drive target device. A power supply system configured to charge a battery cell and supply power from the battery unit to a power supply line in a state where a voltage output from an external power source to a drive target device decreases.
The connection unit is
A parallel line connecting the plurality of battery units in parallel;
A connecting portion for connecting each battery unit to the parallel line;
A control unit for controlling a connection state of the connection unit;
With
The parallel line is connected to the power supply line of the external power supply via an external connection switch that is turned off when the voltage of the power supply line becomes a predetermined value or less.
The connecting portion is
A series circuit of a first switch and a second switch connected in series between the parallel line and the battery unit;
A sub-connection circuit composed of a series circuit of a current limiting resistor and a third switch connected in parallel with the second switch;
A first rectifying element connected in parallel with the first switch and having a rectifying action in a direction of energizing the battery unit from the parallel line;
A second rectifying element connected in parallel with the second switch and having a rectifying action in a direction of energizing the parallel line from the battery unit;
The control unit turns off the first switch of each connection part, turns off the second switch, and turns on the third switch, and precharges each battery unit while equalizing each battery unit. Thereafter, the control unit turns on the first switch of each connection unit, turns on the second switch, turns off the third switch, and makes the battery unit fully charged, and
When each battery unit is fully charged, the control unit turns on the first switch, turns off the second switch, and turns off the third switch of each connection unit, and stops charging the battery unit. Charging mode,
In the full charge mode, when the output voltage of the external power supply decreases, the control unit turns on the first switch, turns on the second switch, and turns off the third switch in each connection unit. A normal discharge mode for supplying power to the power supply line of the external power source from
In the normal discharge mode, when the voltage of the power supply line becomes equal to or lower than the predetermined value, the external connection switch is controlled to be OFF, and the discharge stop mode for stopping the discharge from each battery unit;
In the discharge stop mode, when the cell voltage of the battery unit falls below a predetermined value, the control unit turns off the first switch, turns off the second switch, and turns off the third switch of each connection unit. A power supply system that switches between a drive stop mode and charges / discharges a plurality of battery units.
A plurality of battery units comprising a plurality of battery cells connected in series;
A connection unit for connecting the plurality of battery units in parallel and outputting to the outside,
The connection unit is connected to a power supply line of an external power source that converts power supplied from a commercial power source into direct current and outputs it to a drive target device. A power supply system configured to charge a battery cell and supply power from the battery unit to a power supply line in a state where a voltage output from an external power source to a drive target device decreases.
The connection unit is
A parallel line connecting the plurality of battery units in parallel;
A connecting portion for connecting each battery unit to the parallel line;
A control unit for controlling a connection state of the connection unit;
With
The parallel line is connected to a power supply line of an external power source,
The connecting portion is
A series circuit of a first switch and a second switch connected in series between the parallel line and the battery unit;
A sub-connection circuit composed of a series circuit of a current limiting resistor and a third switch connected in parallel with the second switch;
A first rectifying element connected in parallel with the first switch and having a rectifying action in a direction of energizing the battery unit from the parallel line;
A second rectifying element connected in parallel with the second switch and having a rectifying action in a direction of energizing the parallel line from the battery unit;
The control unit turns off the first switch of each connection unit, turns off the second switch, and turns on the third switch, and precharges the battery units while equalizing each battery unit. Thereafter, the control unit turns on the first switch of each connection unit, turns on the second switch, turns off the third switch, and makes the battery unit fully charged, and
When each battery unit is fully charged, the control unit turns on the first switch, turns off the second switch, and turns off the third switch of each connection unit to stop charging the battery unit. Charging mode,
In the full charge mode, when the output voltage of the external power supply decreases, the control unit turns on the first switch, turns on the second switch, and turns off the third switch in each connection unit. A normal discharge mode for supplying power to the power supply line of the external power source from
When the cell voltage of the battery unit falls below a predetermined value, the control unit switches between a drive stop mode in which the first switch of each connection unit is turned off, the second switch is turned off, and the third switch is turned off. And charging / discharging a plurality of battery units.
An external power source connected to an external commercial power source and converting the power supplied from the commercial power source to supply to the drive target device;
A plurality of battery units comprising a plurality of battery cells connected in series;
A connection unit for connecting the plurality of battery units in parallel and connecting to the external power source,
Power is supplied from the external power supply to each battery unit to charge the battery cell, and power is supplied from the battery unit to the drive target device in a state where the voltage output from the external power supply to the drive target device is reduced. To supply
The external power supply is
A power supply circuit that converts alternating current supplied from a commercial power source into direct current of a predetermined output voltage that drives the drive target device;
A power supply line connected to the output side of the power supply circuit for supplying power to an external drive target device;
A connection line connected to the power supply line and connecting the connection unit;
An external connection switch provided on the connection line and turned off when the voltage of the power supply line is a predetermined value or less;
With
The connection unit is
A parallel line connecting the plurality of battery units in parallel;
A connecting portion for connecting each battery unit to the parallel line;
A control unit for controlling a connection state of the connection unit;
With
The parallel line is connected to a connection line of the external power source,
The connecting portion is
A series circuit of a first switch and a second switch connected in series between the parallel line and the battery unit;
A sub-connection circuit composed of a series circuit of a current limiting resistor and a third switch connected in parallel with the second switch;
A first rectifying element connected in parallel with the first switch and having a rectifying action in a direction of energizing the battery unit from the parallel line;
A charge / discharge control method for a power supply system, comprising: a second rectifier element connected in parallel with the second switch and having a rectifying action in a direction of energizing the parallel line from the battery unit;
The controller turns off the first switch, turns off the second switch, turns on the third switch, and precharges each battery unit while equalizing each battery unit. After the precharging step, the control unit turns on the first switch of each connection unit, turns on the second switch, turns off the third switch, and fully charges the battery unit;
When each battery unit is fully charged, the control unit stops charging the battery unit by turning on the first switch, turning off the second switch, and turning off the third switch of each connection unit. When,
When the output voltage of the external power supply decreases, the control unit turns on the first switch, turns on the second switch, and turns off the third switch of each connection unit. Supplying power to the supply line;
When power is supplied from each battery unit to the power supply line, when the voltage of the power supply line becomes equal to or lower than the predetermined value, the external connection switch is controlled to be turned off to stop discharging from each battery unit. When the cell voltage of the battery unit becomes a predetermined value or less in a state where the discharge from each battery unit is stopped, the control unit turns off the first switch of each connection unit, and turns off the second switch. A charging / discharging control method for a power supply system, wherein a plurality of battery units are charged / discharged in the step of turning off the third switch.