JP2010272218A - Device and method for controlling lithium ion battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To safely carry, remove and scrap a lithium ion secondary battery. <P>SOLUTION: A device for controlling a lithium ion battery pack includes a balance circuit 3 provided in each lithium ion cell 2 to lower a voltage by individually discharging the lithium ion cell 2, and a controller 6 to operate a corresponding balance circuit 3 when the charge voltage of the lithium ion cell 2 is higher than a prescribed voltage, and to operate all balance circuits 3 when the lithium ion battery pack 20 is separated from a charging circuit. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lithium ion assembled battery management apparatus and management method for discharging a lithium ion assembled battery to which a plurality of lithium ion secondary batteries are connected as necessary.

  Lithium ion secondary batteries have advantages such as high energy density and low self-discharge, and are widely used as storage batteries for automobiles, storage batteries for electric / electronic devices, and the like. In addition, in order to obtain a voltage and capacity according to the purpose of use, a battery pack may be configured and used by connecting a plurality of single-cell lithium ion cells.

  On the other hand, in lithium ion secondary batteries, abnormal heat generation occurs due to overcharge, high temperature environment, and the like, and furthermore, there is a risk of ignition accidents because the electrolyte is an organic solvent. For this reason, when left in a high temperature environment, a technique is known in which safety is ensured by discharging a lithium ion secondary battery to release energy (see, for example, Patent Document 1). ).

JP 2007-128818 A

  By the way, the lithium ion secondary battery has a high energy density, so if an impact is given during transportation of the lithium ion secondary battery, a fire accident may occur, and an external short circuit may occur during removal or installation. There is a risk of causing. For this reason, it is desirable to ensure safety by discharging the lithium ion secondary battery during transportation and construction. Further, according to the technique described in Patent Document 1, it is possible to discharge a lithium ion secondary battery, but a discharge resistor is required separately only to ensure safety in a high temperature environment. Equipment costs will be high.

  Accordingly, the present invention provides a lithium ion assembled battery management apparatus and management method capable of ensuring safety by discharging a lithium ion secondary battery before transportation, removal, disposal, etc. and reducing the equipment cost. The purpose is to provide.

  In order to achieve the above object, the invention described in claim 1 is a management apparatus for a lithium ion assembled battery that manages a lithium ion assembled battery in which a plurality of lithium ion secondary batteries are connected in series. A balance circuit that is provided in a secondary battery and lowers the voltage by discharging the lithium ion secondary battery individually, and the corresponding balance circuit is activated when the charging voltage of the lithium ion secondary battery is higher than a predetermined voltage. And control means for operating all the balance circuits when the lithium ion battery pack is disconnected from the charging circuit.

  According to the present invention, when the charging voltage of some of the lithium ion secondary batteries becomes higher than a predetermined voltage during charging, the corresponding balance circuit is operated by the control means, and the lithium ion secondary battery is discharged. Thereby, the charging voltage of a lithium ion secondary battery falls and a voltage is adjusted. When the lithium ion assembled battery is disconnected from the charging circuit, all the balance circuits are operated by the control means, and all the lithium ion secondary batteries are discharged.

  According to a second aspect of the present invention, in the lithium ion assembled battery management device according to the first aspect, the lithium ion assembled battery includes a detection unit that detects that the lithium ion assembled battery has been disconnected from the charging circuit, and the detection by the detection unit. The control means operates all the balance circuits based on the above.

  According to this invention, when the lithium ion assembled battery is disconnected from the charging circuit, this is detected by the detecting means, and all the balance circuits are activated by this detection, and all the lithium ion secondary batteries are discharged.

  According to a third aspect of the present invention, in the lithium ion assembled battery management device according to the first aspect, the control unit includes a monitoring unit that inputs a discharge command to the control unit, and receives the discharge command from the monitoring unit and performs the control. Means actuate all the balancing circuits.

  According to the present invention, when a discharge command is input from the monitoring means to the control means when the lithium ion assembled battery is disconnected from the charging circuit, all the balance circuits are activated and all the lithium ion secondary batteries are discharged.

  According to a fourth aspect of the present invention, in the lithium ion assembled battery management apparatus according to the third aspect, the monitoring means sends a stop voltage command for instructing a discharge stop voltage, which is a voltage for stopping the discharge, to the control means. The control means is operated to receive the stop voltage command from the monitoring means and operate each balance circuit until the voltage of each lithium ion secondary battery reaches the discharge stop voltage.

  According to the present invention, when the stop voltage command is input from the monitoring means to the control means when the lithium ion assembled battery is disconnected from the charging circuit, all the balance circuits are operated and the voltage of each lithium ion secondary battery is discharged. Discharging occurs until the stop voltage is reached.

  According to a fifth aspect of the present invention, a plurality of lithium ion secondary batteries are connected in series, and each lithium ion secondary battery is provided with a balance circuit that individually discharges the lithium ion secondary battery to lower the voltage. A lithium ion battery management method for managing a lithium ion battery, wherein when the charging voltage of the lithium ion secondary battery is higher than a predetermined voltage, the corresponding balance circuit is operated to operate the lithium ion battery. The charging voltage of the secondary battery is adjusted, and when the lithium ion battery is disconnected from the charging circuit, all the lithium ion secondary batteries are discharged by operating all the balance circuits. To do.

  According to the first and fifth aspects of the invention, when the lithium ion assembled battery is disconnected from the charging circuit, that is, when the lithium ion assembled battery is transported (moved) or removed, all the lithium Since the ion secondary battery is discharged, safety such as transportation and removal can be ensured. In addition, the balance circuit is used not only for voltage adjustment of each lithium ion secondary battery but also for discharging when disconnected from the charging circuit, so there is no need to provide a separate resistor for discharging, reducing equipment costs. It becomes possible to do.

  According to the invention described in claim 2, since the balance circuit is activated by detecting that the lithium ion assembled battery has been disconnected from the charging circuit, it is possible to reliably discharge all the lithium ion secondary batteries. .

  According to the invention described in claim 3, since the balance circuit is operated by inputting a discharge command from the monitoring means, all lithium ions can be flexibly and arbitrarily selected according to the installation / operation status of the lithium ion battery pack. The ion secondary battery can be discharged.

  According to the invention described in claim 4, all the lithium ion batteries are input by inputting the discharge stop voltage from the monitoring means in accordance with the purpose of disconnecting the lithium ion assembled battery from the charging circuit, that is, the purpose of transportation, removal, or disposal. The ion secondary battery can be discharged to a discharge stop voltage according to the purpose. As a result, it is possible to carry out transportation, removal and disposal appropriately while ensuring safety.

It is a schematic block diagram which shows the state which applied the lithium ion assembled battery system which concerns on Embodiment 1 of this invention to the uninterruptible power supply device. It is a schematic block diagram which shows the state which applied the lithium ion assembled battery system provided with the management apparatus which concerns on Embodiment 2 of this invention to the uninterruptible power supply device. It is a schematic block diagram which shows the modification of the management apparatus of FIG.

  The present invention will be described below based on the illustrated embodiments.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram showing a state in which a lithium ion assembled battery system 1 according to this embodiment is applied to an uninterruptible power supply (UPS). In this lithium ion assembled battery system 1, a plurality of lithium ion cells (lithium ion secondary batteries) 2 that are unit cells are connected in series to form a lithium ion assembled battery 20, and such a lithium ion assembled battery 20 is managed. The management apparatus which performs is provided.

  This management apparatus mainly includes a balance circuit 3 and a voltmeter 4 provided in each lithium ion cell 2, a single main switch 5, a controller (control means) 6 and a monitoring device (monitoring means) 7. Yes. Each balance circuit 3, each voltmeter 4, and the main switch 5 are connected to the controller 6 so as to be able to communicate (data transmission), and the controller 6 and the monitoring device 7 are also connected so as to be able to communicate. In this embodiment, the monitoring device 7 is installed at a location away from the installation location of the lithium ion assembled battery 20, and a plurality of controllers 6 can be connected to one monitoring device 7. 7, a plurality of controllers 6 can be monitored and controlled.

  The balance circuit 3 is a circuit that discharges the corresponding lithium ion cell 2 to lower the voltage. Specifically, the discharge resistor 31 and the discharge switch 32 are connected in series, and are connected in parallel with the lithium ion cell 2. As will be described later, in a normal state, the discharge switch 32 is turned off (closed) in response to a closing command from the controller 6 while the discharge switch 32 is turned off (opened). Thereby, the lithium ion cell 2 is discharged by the discharge resistor 31 as a load, and the voltage is lowered.

  The voltmeter 4 is connected in parallel to the corresponding lithium ion cell 2, measures the voltage of the lithium ion cell 2 during charging and discharging, and transmits the measurement result to the controller 6 in real time.

  The main switch 5 is a switch that controls a charging current to the lithium ion assembled battery 20, and is provided in a charging circuit that supplies power to the lithium ion assembled battery 20. That is, it is connected between the AC / DC converter 101 and the lithium ion assembled battery 20 (charging circuit), the electric power from the commercial power source 100 is converted into DC by the AC / DC converter 101, and the lithium ion is supplied via the main switch 5. It is supplied to the assembled battery 20. As will be described later, the main switch 5 is normally turned on (closed), and is turned off (opened) in response to an opening command from the controller 6.

  A bypass diode 8 is connected in parallel with the main switch 5. The bypass diode 8 has a function of allowing only a current flow from the lithium ion assembled battery 20 and prevents a current from flowing to the lithium ion assembled battery 20. Thereby, discharge from the lithium ion assembled battery 20 is always possible, and power is supplied from the lithium ion assembled battery 20 to the load facility 103 via the bypass diode 8. Here, the commercial power source 100 and the load facility 103 are connected via an AC / DC converter 101 and a DC / AC converter 102, and in normal times, the power from the commercial power source 100 is converted to both the converter 101 and the converter. It is converted at 102 and supplied to the load facility 103.

  The controller 6 is a device that controls each balance circuit 3 and the main switch 5 based on the measurement result from each voltmeter 4 and the control command from the monitoring device 7. Specifically, when the charging voltage of any lithium ion cell 2 is higher than a predetermined voltage during the float charging, a close command is transmitted to the balance circuit 3 of the lithium ion cell 2. As a result, the discharge switch 32 of the balance circuit 3 is closed, the lithium ion cell 2 is discharged, and the charging voltage is lowered.

  Further, when the charging voltage of the lithium ion cell 2 discharged as described above falls below a predetermined voltage, an open command is transmitted from the controller 6 to the corresponding balance circuit 3. Thereby, the discharge switch 32 is opened and the discharge of the lithium ion cell 2 is stopped. In this way, the charging voltage of each lithium ion cell 2 is adjusted (variation is eliminated).

  Further, when a discharge command as will be described later is received from the monitoring device 7, an open command is transmitted from the controller 6 to the main switch 5 and a close command is transmitted to all the balance circuits 3. Thereby, the main switch 5 is turned off and the charging current to the lithium ion assembled battery 20 is cut off, that is, the lithium ion assembled battery 20 is disconnected from the charging circuit, and all the discharge switches 32 are closed, The ion cell 2 starts discharge (all cell discharge).

  Further, when a stop voltage command as described later is received from the monitoring device 7 and the voltage of each lithium ion cell 2 reaches the discharge stop voltage in the above-described all-cell discharge state, the lithium ion cell 2 An open command is transmitted to the balance circuit 3. Thereby, the discharge switch 32 of the balance circuit 3 is opened, and the discharge of the lithium ion cell 2 is stopped. In this way, discharge is performed until each lithium ion cell 2 reaches the discharge stop voltage. Further, when the purpose is to remove or dispose of the lithium ion assembled battery 20, that is, when the discharge stop voltage in the stop voltage command is zero volts as will be described later, the main switch 5 is maintained in the OFF state and recharged. I can't do it.

  Such a controller 6 has a function of transmitting monitoring data such as a measurement result from each voltmeter 4 and an opening / closing state of each discharge switch 32 to the monitoring device 7 in real time. Furthermore, a display unit such as an LED is provided to display the state of each lithium ion cell 2, for example, the state of charging, discharging of all cells, or the end of discharging.

  The monitoring device 7 is composed of a personal computer or the like, receives the above monitoring data from the controller 6 and monitors the lithium ion assembled battery 20, and transmits and inputs a control command to the controller 6. . That is, an input unit such as a keypad and a display such as an LCD are provided, and the controller 6 is controlled by inputting a discharge command, a stop voltage command, or the like from the input unit to the controller 6. Here, the discharge command is a command for discharging all the lithium ion cells 2 as described above, and the stop voltage command is a command for designating and instructing a discharge stop voltage that is a voltage for stopping the discharge in all cell discharges. is there.

  Furthermore, the discharge stop voltage is set according to the purpose of discharging all the lithium ion cells 2, that is, the purpose of disconnecting the lithium ion assembled battery 20 from the charging circuit. For example, the discharge stop voltage is set to the discharge end voltage on the specification of the lithium ion cell 2 (the voltage on which the discharge is ended on the specification) by inputting and selecting the transportation as an object in the input unit. Thereby, it becomes possible to carry safely without affecting the performance of the lithium ion cell 2. Moreover, the discharge stop voltage is set to zero volts by inputting and selecting removal / discarding as a purpose. As a result, the lithium ion cell 2 can be safely removed and discarded.

  Next, the operation of the management apparatus having such a configuration and a method for managing a lithium ion assembled battery using the management apparatus will be described.

  First, during normal float charging, the main switch 5 is in an on state, and the discharge switches 32 of all the balance circuits 3 are in an off state. Then, power from the commercial power source 100 is supplied to the load facility 103 via the converters 101 and 102 and also supplied to the lithium ion assembled battery 20 via the AC / DC converter 101 and the main switch 5.

  In such a charged state, the voltage of the lithium ion cell 2 is always measured by each voltmeter 4 and the measurement result is transmitted to the controller 6 in real time. When the charging voltage of any lithium ion cell 2 is higher than a predetermined voltage, a closing command is transmitted from the controller 6 to the balance circuit 3 of the lithium ion cell 2. As a result, the lithium ion cell 2 is discharged as described above, and the charging voltage is lowered. Further, when the charging voltage of the lithium ion cell 2 falls below a predetermined voltage, an open command is transmitted from the controller 6 to the corresponding balance circuit 3. Thereby, the discharge of the lithium ion cell 2 is stopped, and the charging voltage of each lithium ion cell 2 is adjusted in this way.

  When the power supply from the commercial power supply 100 is stopped (power failure) in such a charged state, the lithium ion assembled battery 20 starts discharging instantaneously (without instantaneous interruption) via the bypass diode 8, and the lithium ion assembled battery 20 Is supplied to the load facility 103 via the DC / AC converter 102. Even in this discharge state, the voltage of each lithium ion cell 2 is transmitted to the controller 6 in real time.

  Further, when the lithium ion assembled battery 20 is moved (transported), removed or discarded, the lithium ion assembled battery 20 is disconnected from the charging circuit. That is, when a discharge command including the purpose of disconnection is input from the input unit of the monitoring device 7, a discharge command and a stop voltage command for instructing a discharge stop voltage suitable for the purpose are input and transmitted to the controller 6. For example, as described above, a stop voltage command with the discharge stop voltage as the discharge end voltage is transmitted for the purpose of transportation, and the discharge stop voltage is set to zero volts for the purpose of removal and disposal. A stop voltage command is transmitted. As a result, an open command is transmitted from the controller 6 to the main switch 5 to stop the charging of the lithium ion assembled battery 20, and a close command is transmitted to all the balance circuits 3, so that all the lithium ion cells 2 Is started to discharge.

  Thereafter, when the voltage of each lithium ion cell 2 reaches the discharge stop voltage, an open command is sequentially transmitted to the balance circuit 3 of each lithium ion cell 2. Thereby, the discharge of each lithium ion cell 2 is stopped sequentially, and all the lithium ion cells 2 are discharged to the discharge stop voltage. At this time, the display indicating the end of the discharge of each lithium ion cell 2 is sequentially displayed on the display unit of the controller 6, and when the discharge of all the lithium ion cells 2 is completed, this is displayed on the display of the monitoring device 7. The And according to the objective, the lithium ion assembled battery 20 is conveyed, removed, or discarded.

  As described above, according to the management device and the management method, when the lithium ion battery pack 20 is transported or removed, all the lithium ion cells 2 are discharged. Can be secured. Moreover, since each lithium ion cell 2 is discharged to a discharge stop voltage according to the purpose of transportation, removal, disposal, etc., it is possible to carry out transportation, removal, disposal, etc. properly while ensuring safety. .

  In addition, by inputting a discharge command or the like from the monitoring device 7 to the controller 6, all lithium ion secondary batteries can be discharged flexibly and arbitrarily according to the installation / operation status of the lithium ion assembled battery 20. Can do. Furthermore, since the balance circuit 3 is used not only for adjusting the voltage of each lithium ion cell 2 but also for discharging all cells when disconnected from the charging circuit, the balance circuit 3 is effectively utilized and equipment costs are reduced. Is possible.

(Embodiment 2)
FIG. 2 is a schematic configuration diagram illustrating a state in which the lithium ion assembled battery system 1 including the management device according to this embodiment is applied to an uninterruptible power supply device. Here, about the structure equivalent to Embodiment 1, the description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  The management device includes a detection unit that detects that the lithium ion assembled battery 20 is disconnected from the charging circuit, and the controller 6 operates all the balance circuits 3 based on the detection by the detection unit. The configuration is different from that of Form 1. That is, an ammeter 9 for measuring charging current and discharging current is connected between the main switch 5 (bypass diode 8) and the lithium ion assembled battery 20 (charging circuit), and the measurement result by the ammeter 9 is obtained in real time. The data is transmitted to the controller 6. When the charging current measured by the ammeter 9 is zero, the controller 6 determines (detects) that the lithium ion assembled battery 20 has been disconnected from the charging circuit, and the main switch 5 is the same as in the first embodiment. Is turned off and all the lithium ion cells 2 are discharged. Here, in normal float charging, when there is an event that the charging current is balanced and becomes zero temporarily or intermittently by reaching full charge, it continues for a predetermined time to distinguish this event. When the charging current is zero, it is determined that the lithium ion assembled battery 20 has been disconnected from the charging circuit.

  Thus, according to this embodiment, it is detected reliably that the lithium ion assembled battery 20 has been disconnected from the charging circuit, and all the balance circuits 3 are operated. All the lithium ion cells 2 can be discharged. Here, when the charging current is zero, it is determined that the lithium ion assembled battery 20 is disconnected from the charging circuit, but as shown in FIG. 3, by detecting that the main switch 5 is turned off, It may be determined that the lithium ion assembled battery 20 has been disconnected from the charging circuit. In this case, the main switch 5 is not controlled to be opened and closed by the controller 6, but is controlled by another control unit or manually.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the first embodiment, the controller 6 and the monitoring device 7 are separated from each other. However, the controller 6 may be integrated and a discharge command, a stop voltage command, or the like may be input in the controller 6. In the first embodiment, the purpose of disconnection is input from the input unit of the monitoring device 7. However, depending on the usage period or the degree of deterioration of the lithium ion battery pack 20, the purpose of disposal, relocation, transport, etc. May be automatically determined, and the discharge stop voltage may be set. Furthermore, a plan such as relocation or disposal may be input to the monitoring device 7 in advance, and a control command may be transmitted from the monitoring device 7 to the controller 6 based on this plan.

  Further, although one controller 6 is provided for one set of lithium ion battery pack 20, a plurality of controllers 6 may be provided according to the number of connected lithium ion cells 2. For example, six to twelve lithium ion cells 2 may be used as one module, and a controller 6 may be provided for each module to perform discharge. At this time, the state in which the main switch 5 and the bypass diode 8 are further provided may be regarded as one unit, and each unit may be monitored and controlled by the monitoring device 7. In this case, in the second embodiment, it may be mechanically detected that the module (unit) is removed from the charging circuit, and all the balance circuits 3 may be operated by the detection.

  Moreover, although the system which has one set of lithium ion assembled batteries 20 was demonstrated, it is applicable also to the system which connected multiple lithium ion assembled batteries 20. Furthermore, although the case where the lithium ion assembled battery system 1 was applied to an uninterruptible power supply device has been described, the present invention can also be applied to a rectifier, an automobile storage battery, and the like.

1 Lithium ion battery system 2 Lithium ion cell (lithium ion secondary battery)
20 Lithium-ion battery 3 Balance circuit 31 Discharge resistor 32 Discharge switch 4 Voltmeter 5 Main switch 6 Controller (part of control means and detection means)
7 Monitoring device (monitoring means)
8 Bypass diode 9 Ammeter (part of detection means)

Claims (5)

A lithium-ion battery management device that manages a plurality of lithium-ion secondary batteries connected in series,
A balance circuit that is provided in each of the lithium ion secondary batteries and discharges the lithium ion secondary batteries individually to lower the voltage;
When the charging voltage of the lithium ion secondary battery is higher than a predetermined voltage, the corresponding balance circuit is activated, and all the balance circuits are activated when the lithium ion assembled battery is disconnected from the charging circuit. Control means;
A lithium-ion battery management apparatus comprising:   2. The apparatus according to claim 1, further comprising detection means for detecting that the lithium ion assembled battery is disconnected from the charging circuit, wherein the control means operates all the balance circuits based on detection by the detection means. The management apparatus of the lithium ion assembled battery as described in.   2. The lithium ion according to claim 1, further comprising a monitoring unit that inputs a discharge command to the control unit, wherein the control unit operates all the balance circuits in response to the discharge command from the monitoring unit. Battery management device. The monitoring means inputs a stop voltage command for instructing a discharge stop voltage, which is a voltage for stopping discharge, to the control means,
4. The control circuit according to claim 3, wherein the control circuit operates each balance circuit until the voltage of each lithium ion secondary battery reaches the discharge stop voltage in response to a stop voltage command from the monitoring means. The management apparatus of lithium ion assembled battery of description. A plurality of lithium ion secondary batteries connected in series, and a balance circuit that individually discharges the lithium ion secondary batteries to lower the voltage manages lithium ion assembled batteries provided in each lithium ion secondary battery. A method for managing an ion battery,
When the charging voltage of the lithium ion secondary battery is higher than a predetermined voltage, by adjusting the corresponding balance circuit, the charging voltage of the lithium ion secondary battery is adjusted,
A method for managing a lithium ion assembled battery, wherein when the lithium ion assembled battery is disconnected from a charging circuit, all the lithium ion secondary batteries are discharged by operating all the balance circuits.

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