JP2018133949A - Storage battery control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery control device capable of preventing destruction of a diode by limiting current flowing when a hot line is connected.SOLUTION: An element for limiting an inrush current at a time of hot line connection and a switch for short-circuiting a current limiting element after the hot line connection is completed are provided not at a bypass capacitor of a cell controller IC but at an input signal line of the cell controller IC to protect the cell controller IC.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a storage battery control device.

Electric vehicles and hybrid vehicles use battery modules in which a plurality of assembled batteries connected in series or series-parallel with secondary battery cells (single batteries) such as lithium cells are connected in series or series-parallel. doing. A plurality of battery modules connected in series or in series and parallel are used as a power storage device together with a battery control device for controlling these battery modules.

  When connecting a secondary battery cell connected in series with a control device for detecting the voltage of these batteries (hot-wire connection), a device that prevents a large current from flowing through the integrated circuit is necessary.

  For example, in Patent Document 1, when connecting a battery pack (assembled battery) in which a plurality of secondary batteries are connected in series and parallel to a control device, pins having the same potential are connected between the connectors so that no current flows across the connectors. It is divided.

Patent Document 2 discloses a cell controller IC for limiting a current flowing through a capacitor inserted in parallel to a power source of a cell controller IC when a live connection is made to connect an assembled battery and a cell controller IC (integrated circuit). A circuit is provided in which a current limiting element is inserted into a bypass capacitor that is inserted in parallel with the power supply pin, a switch provided in parallel with the current limiting element is closed after the live connection is completed, and the current limiting element is short-circuited. Yes.

JP2011-253777A International Patent Publication WO2013 / 140605

  The method described in Patent Document 1 has the problem that two pins are assigned to one voltage detection line, which increases the number of pins of the connector and increases the cost.

  The method described in Patent Document 2 has a problem in that a switch is inserted into a bypass capacitor, the external noise absorption capability is reduced, and the external noise is weakened.

  In order to solve the above-described problems, the present invention provides a cell controller IC, not a bypass capacitor of a cell controller IC, but an element that limits an inrush current at the time of hot line connection and a switch that short-circuits the current limit element after the hot line connection is completed. Are provided on the input signal line to protect the cell controller IC.

  According to the present invention, the cell controller IC can be protected from external noise while protecting the cell controller IC when the live line is connected to the storage battery control device, and the number of pins of the connector can be increased. There is.

It is a block diagram which shows the outline | summary of the structural example at the time of applying this invention to the drive device of the rotary electric machine for hybrid vehicles. It is a figure which shows the structural example of the battery control apparatus which is 1st Embodiment by this invention. It is a figure which shows one example of the internal structure of the cell controller contained in the battery control apparatus of FIG. It is a figure for demonstrating the inrush current at the time of hot line connection of an assembled battery and cell controller IC. It is a figure for demonstrating the inrush current limiting circuit at the time of the assembled battery and cell controller IC hot wire connection of a prior art document. It is a figure which shows 1st Embodiment of the storage battery control apparatus of this invention.

  Hereinafter, examples will be described with reference to the drawings.

<Overall configuration of motor drive device including battery control device>
First, an overall configuration of a drive system that can be applied to a rotating electrical machine (motor generator) used in an electric vehicle such as an electric vehicle and a hybrid vehicle including the battery control device according to the present invention will be described with reference to FIG. .
FIG. 1 is a block diagram showing a drive system for a vehicular rotating electrical machine. The drive system shown in FIG. 1 includes a battery module 20, a battery control device 1 that monitors the battery module 20, an inverter device 220 that converts DC power from the battery module 20 into three-phase AC power, and a motor generator for driving a vehicle. 230 is provided. The motor generator 230 is driven by the three-phase AC power from the inverter device 220. The inverter device 220 and the battery control device 1 are connected by CAN communication, and the inverter device 220 functions as a host controller for the battery control device 1. Further, the inverter device 220 operates based on command information from the vehicle controller 6 (see FIG. 1), which is a higher-level control device.
A battery module 20 shown in FIG. 1 is configured by connecting two cell groups 2 each having a plurality of secondary battery cells (single cells) such as lithium battery cells connected in series. Each cell group is monitored and controlled by a cell controller 11 provided corresponding to each cell group. These cell controllers 11 are incorporated in the battery control device 1.
The two cell groups 2 are connected in series via a maintenance / inspection service disconnect (SD) 3 in which a switch and a fuse are connected in series. By opening this service disconnect SD-SW, the series circuit of the electric circuit is cut off, and even if a connection circuit is formed at one place between the battery module block 20 and the vehicle, no current flows. With such a configuration, high safety can be maintained. Even if an operator touches between HV + and HV− during inspection, it is safe because a high voltage is not applied to the human body.
The power module 226 of the inverter device 220 conducts and cuts off at high speed and performs power conversion between DC power and AC power. At this time, since a large current is interrupted at a high speed, a large voltage fluctuation occurs due to the inductance of the DC circuit. In order to suppress this voltage fluctuation, a large-capacity smoothing capacitor (not shown) of about 700 μF to about 2000 μF is provided between the high voltage lines HV + and HV− connected to the power module 226. Thereby, the voltage noise added to the integrated circuit provided in the battery control apparatus 1 is reduced.
A high-voltage line HV + between the battery module 20 and the inverter device 220 is provided with a battery disconnect unit BDU including a relay RL, a resistor Rp, and a precharge relay RLp. A series circuit of the resistor RP and the precharge relay RLp is connected in parallel with the relay RL. On the other hand, a relay Rr is connected to the high voltage line HV−, and a battery disconnect switch SD is arranged. The battery disconnect switch SD and the battery disconnect unit BUD allow the battery module 20 to be completely disconnected from the inverter device 220 side.

When the inverter device 220 starts operating, the charge of the smoothing capacitor is substantially zero, and when the relay RL is closed, a large initial current flows into the smoothing capacitor. The relay RL may be fused and damaged due to the large current. In order to solve this problem, the motor control microcomputer (MCU) 222 further switches the relay Rr and the precharge relay RLp from the open state to the closed state at the start of driving of the motor generator 230 in accordance with a command from the vehicle controller 6. The smoothing capacitor is charged, and then the relay RL is changed from the open state to the closed state, and supply of power from the battery module 20 to the inverter device 220 is started. When charging the smoothing capacitor, charging is performed while limiting the maximum current via the resistor Rp. By performing such an operation, the relay circuit can be protected, and the maximum current flowing through the battery cell and the inverter device 220 can be reduced to a predetermined value or less, and high safety can be maintained.
The inverter device 220 controls the phase of AC power generated by the power module 226 with respect to the rotor of the motor generator 230, and operates the motor generator 230 as a generator during vehicle braking. That is, regenerative braking control is performed, and the battery module 20 is charged by regenerating the power generated by the generator operation to the battery module 20. When the state of charge of the battery module 20 is lower than the reference state, the inverter device 220 operates using the motor generator 230 as a generator. The three-phase AC power generated by the motor generator 230 is converted into DC power by the power module 226 and supplied to the battery module 20. As a result, the battery module unit 20 is charged.
On the other hand, when the motor generator 230 is used as a motor for power running, the MCU 222 controls the driver circuit 224 to generate a rotating magnetic field in the forward direction with respect to the rotation of the rotor of the motor generator 230 in accordance with a command from the vehicle controller 6. Then, the switching operation of the power module 226 is controlled. In this case, DC power is supplied from the battery module 20 to the power module 226. Further, when the battery module 20 is charged by regenerative braking control, the MCU 222 controls the driver circuit 224 so as to generate a rotating magnetic field in a delay direction with respect to the rotation of the rotor of the motor generator 230, and the power module. The switching operation of H.226 is controlled. In this case, electric power is supplied from the motor generator 230 to the power module 226, and DC power of the power module 226 is supplied to the battery module 20. As a result, the motor generator 230 acts as a generator.
The battery control device 1 mainly performs cell voltage measurement, total voltage measurement, current measurement, cell temperature, cell capacity adjustment, and the like of each single battery cell constituting the cell group 2. For this purpose, a plurality of battery control ICs (integrated circuits) are provided as the cell controller 11 as described above.
In addition, the case where the battery module 20 of FIG. 1 is comprised by two cell groups as an example is shown. The battery module 20 is configured by connecting a plurality of cell groups as described above in series or series-parallel in order to obtain a voltage and current required for an electric vehicle and a hybrid vehicle. Further, a plurality of such battery modules may be connected in series or series-parallel. The cell controller 11 is provided corresponding to each of these cell groups.

FIG. 2 is a diagram showing a configuration example of the battery control device 1 of the assembled battery (battery module 20) according to the first embodiment of the present invention. In the first embodiment, four cell groups 2 in which 12 lithium ion batteries are connected in series are connected in series. The DC power of the battery module 20 is supplied to the inverter device 220 (see FIG. 1) from the positive electrode bus bar terminal 7 connected to the positive electrode of the battery module 20 and the negative electrode bus bar terminal 8 connected to the negative electrode.
The battery control device 1 of the assembled battery includes a total voltage of the cell group 2, a cell voltage of the single battery cells constituting the cell group 2, a current value input / output from the assembled battery input from a current sensor (not shown), and not shown. The temperature of the cell group 2 input from the temperature sensor is detected and transmitted via the communication line 61 to the vehicle controller 6 corresponding to the host controller.
Further, when the voltage of the single cells constituting the cell group 2 varies from a predetermined value, the battery control device 1 performs a capacity adjustment process that reduces variation.
The battery control device 1 of the cell group 2 includes a battery control microcomputer (MPU) 10, a cell controller IC 11, a total voltage measurement circuit 14, a temperature sensor input circuit 15, a current sensor input circuit 16, an activation circuit unit 52, an insulation pulse transformer 13, The power supply circuit 16 and the communication circuit 17 are included. The MPU 10 collects battery information measured by the measurement circuit in the battery control device 1 and transmits it to the vehicle controller 6 from the communication circuit 17 via the communication line 61. Further, the MPU 10 transmits a capacity adjustment instruction from the vehicle controller 6 to adjust the capacity of each of the plurality of unit cells constituting the cell group to the cell controller 11 via the insulating pulse transformer 13.

The cell controller ICs 11 are daisy chain connected via a differential signal communication line 602, and a signal is input from the battery control microcomputer (MPU) 10 to the communication interface IC 51 through the insulating pulse transformer 13.
The power supply circuit 16 starts to operate in response to a start signal 62 from the vehicle controller 6 and inputs a battery voltage supplied from the battery 5. The MPU 10 and the communication circuit 17 in the battery control device 1 are used as power sources for these operations. Supply voltage.

  The cell controller IC 11 is supplied with power from the cell group 2 and starts operation in response to an activation signal input through the insulation pulse transformer 13. Further, the cell controller IC 11 uses the negative potential line 29 of the cell group 2 as a GND reference, and is electrically insulated from the vehicle chassis 30.

Next, the internal configuration of the cell controller IC 11 will be described with reference to FIG.
The cell controller IC 11 includes a discharge circuit unit 21, a multiplexer 22, an AD converter 23, a discharge control unit 24, a communication circuit unit 25, an internal power supply circuit unit 26, and a startup circuit 27.
When an activation signal is input from the activation circuit 27 to the internal power supply circuit 26, the internal power supply circuit unit 26 is connected to the discharge circuit unit 21, the multiplexer 22, the AD converter 23, the discharge control unit 24, and the communication circuit unit 25 in the IC. These operating power supplies VDD are supplied.
The cell controller IC 11 is connected to a plurality of unit cells constituting the cell group 2 by voltage detection lines 213 provided corresponding to each unit cell, and the cell voltage of each unit cell is input to the multiplexer 22. Is done. The voltage of the single battery cell selected by the multiplexer is input to the AD converter 23 by the control signal from the control block 24, and AD sampling measurement is performed to measure the cell voltage of the single battery cell. The voltage measurement value sampled and measured by the AD converter 23 is sent to the communication circuit 25 via the control block 24. And the communication circuit 25 transmits the battery information of the some single battery cell which comprises the cell group 2 collected by differential signal Tx-H and Tx-L to the IC exterior.
The discharge circuit unit 21 includes a balancing resistor RB and a balancing switch QB that are provided corresponding to each of the plurality of single cells constituting the cell group 2. The balancing switch QB is connected between the voltage detection line connected to the positive electrode and the voltage detection line connected to the negative electrode of each unit cell, and is selected by the control signal from the discharge control unit 24. By turning ON, the single battery cell, the balancing resistor RB, and the balancing switch QB constitute a discharge circuit for each single battery cell. With the discharge circuit for each single battery cell, the single battery cell that needs capacity adjustment is discharged, and balancing discharge is performed to make the capacity of the single battery cells in the entire cell group uniform.

<Connection structure of conventional battery pack and storage battery control device>
Next, with reference to FIG. 4, the problem in the hot-wire connection of an assembled battery (cell group) and a storage battery control apparatus is demonstrated.

  In FIG. 4, battery module blocks 2A, 2B and 2C are shown. In the battery module block 2A, BC48 to BC36 are single cell batteries (battery cells) VS48 to VS36 such as lithium single batteries, VS48 to VS36 are voltage detection lines for detecting terminal voltages of the respective batteries, and CN1 is a voltage detection line connected to the storage battery control device 1. It is a connector to do. The connector CN1 is a connector connected to the battery module blocks 2A, 2B, and 2C and cell controllers IC1, IC2, and IC3 that control these cell groups, respectively.

    The power input DCIN of each cell controller IC is connected to the highest potential voltage detection line of the cell module connected to each cell controller IC, and the GND side wiring of the cell controller IC is the lowest potential voltage of the cell group. Connected to the detection line. For example, the DCIN wiring of the cell controller IC1 is connected to the voltage detection line VS48, and the GND side wiring is connected to the voltage detection line VS36.

  Each of these cell controller ICs includes a power supply terminal indicated by DCIN and GNDL, a GND terminal, a high voltage HV terminal in the cell controller IC generated from DCIN by a charge pump, and a discharge circuit output terminals SW0 to SW12. It incorporates a diode for ESD (electrostatic discharge) protection.

  C1A, C1B to C3A, C3B are bypass capacitors for voltage stabilization of each cell controller IC.

The connection structure shown in FIG. 4 that connects the assembled battery and the storage battery control device has the following problems.
For example, when the charged battery and the storage battery control device 1 are hot-wired, the order in which the terminals are connected cannot be controlled with a general connector, so depending on the order in which the voltage detection lines are connected, the cell controller in the storage battery control device 100 The ESD protection diode in the IC 11 may have a current that exceeds the withstand capability of the diode and may destroy the ESD protection diode.

  A mechanism by which an overcurrent flows through the ESD protection diode in the cell controller IC 11 will be described.

  As an example, it is assumed that the voltage detection lines VS47 and VS12 are connected first, and the other voltage detection lines are not connected. In this case, as indicated by the thick broken line arrow in FIG. 4, the inrush current at the time of live connection is the voltage detection line VS36 from the voltage detection line VS47 via the ESD diode D1 and the bypass capacitor C1B in the cell controller IC1. To flow. From there, the current path is divided into two, one path flows from the discharge resistance R2B to the voltage detection line VS24 through the ESD protection diode D2 inside the IC2, and the other path from the reverse connection protection diode D2A through the power supply series resistance R2A. , Flows to the voltage detection line VS24 through the bypass capacitor C2A, merges there, and then splits into two paths. One path passes through the discharge resistor R4B, passes through the ESD protection diode D3 in the IC3, and passes through the bypass capacitor C4B. The other path to VS12 flows through the power supply series resistor R3A, from the reverse connection protection diode D3A to the voltage detection line VS12 through the bypass capacitor C3A.

The inrush current decreases exponentially as the bypass capacitors C1A, C1B to C3A, C3B are charged.
The inrush current varies depending on the discharge resistance, the resistance value of the power supply series resistance, the capacitance of the bypass capacitor, and the voltage of the connected battery. The discharge resistance value depends on the cell capacity adjustment requirements. The maximum resistance value is determined, and the resistance value of the power supply series resistor is determined by the power supply current value of the cell controller IC, and the resistance value cannot be increased to reduce the inrush current.
In addition, the capacitance of the bypass capacitor is determined to be stable for the power supply voltage of the cell controller IC, and the capacitance cannot be reduced to reduce the inrush current.

From the above, when the storage battery control device 100 equipped with the cell controllers IC1 to IC4 is hot-connected to the battery module 20, that is, the cell groups 20A1, 20A2, 20B1, and 20B2, it is necessary to protect the cell controller IC against inrush current outside the IC. become.

<Connection structure of battery pack and storage battery control device of Prior Art Document 2>
In prior art document 2, in order to solve the above-mentioned problem, in order to limit the current flowing through the ESD diode in the cell controller IC 11 when the live line is connected, a current limiting element for limiting the current is inserted into the bypass capacitor through which the current flows. After the live connection, a circuit for short-circuiting the current limiting element is added to protect the components during the live connection and perform normal operation after startup.

  In the method described in Prior Art Document 2, an element having a switch function is inserted in series with a bypass capacitor for the purpose of noise absorption, which may reduce the noise absorption capability.

  A method for protecting the cell controller IC during live line connection without impairing the noise absorption capability of the bypass capacitor will be described below with reference to the first embodiment.

<First Embodiment>
FIG. 6 is an example showing the first embodiment of the present invention. Hereinafter, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, the cell controller IC described above is compared with the comparative example shown in FIG.
The current limiting element R2F and the switch SW1 for short-circuiting the limiting element are connected to a current path in which an overcurrent may flow through the ESD diode, that is, the uppermost discharge circuit of the cell controller IC1.

This switch SW1 is off, that is, is open when the cell controller IC1 is not in an on state, that is, not activated, and an inrush current at the time of hot line connection flows through the current limiting element R2F. With this configuration, the current that flows when the ESD protection diode D1 described with reference to FIG. 4 is connected to the live line is limited, and the diode can be prevented from being destroyed.

  The switch SW1 is turned on by the voltage VAA output from the internal power supply of the cell controller IC after the cell controller IC 11 is activated by an activation signal from the outside after the live line connection is completed, thereby short-circuiting the current limiting element R2F. After the switch SW1 is short-circuited, the current flowing through the discharge circuit is normal, and the discharge operation is not affected.

  The features of the present invention will be briefly summarized below. The storage battery control device according to the present invention controls an assembled battery in which a plurality of secondary battery cells are connected, and is electrically detachably connected to the assembled battery via a connector, and uses the voltage of the assembled battery. At least one integrated circuit having a power supply for supplying power and monitoring and controlling charging / discharging of each secondary battery cell of the assembled battery, and connected in series to an input signal terminal of the integrated circuit, the assembled battery and the integrated circuit At least one current limiting element for limiting the current flowing through the path when electrically connected to the current path, and the current limiting element, and is turned on by the supply of the internal power supply of the integrated circuit and the first current limiting element When at least one switch for short-circuiting an element and the battery pack and the integrated circuit are electrically connected, when the integrated circuit is not activated and the internal power is not supplied from the power source, The When the switch is turned off, the charging current flows to the first current limiting element. After the assembled battery and the integrated circuit are electrically connected to start the integrated circuit, the internal power is supplied from the power source. When the switch is turned on, the current limiting element is short-circuited. By adopting such a configuration, after the switch SW1 is short-circuited, the current flowing through the discharge circuit becomes normal and does not affect the discharge operation.

  Further, in the storage battery control device according to the present invention, the current limiting element is inserted into the discharge circuit that is connected to the uppermost cell of the assembled battery connected to the integrated circuit.

  The storage battery control device of the present invention is characterized in that the resistance value of the discharge current setting set in the discharge circuit into which the current limiting element is inserted is set to a value obtained by subtracting the impedance component of the switch circuit. With such a structure, a more accurate circuit configuration can be obtained and the diode can be prevented from being destroyed.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

Claims (3)

A storage battery control device for controlling an assembled battery in which a plurality of secondary battery cells are connected,
The battery pack is electrically connected to the battery pack via a connector and has a power supply for supplying an internal power supply using the voltage of the battery pack, and monitoring charge / discharge of each secondary battery cell of the battery pack And at least one integrated circuit for controlling;
At least one current limiting element that is connected in series to an input signal terminal of the integrated circuit and limits a current flowing through the path when the assembled battery and the integrated circuit are electrically connected;
At least one switch that is provided in parallel with the current limiting element and that is turned on by the supply of internal power of the integrated circuit to short-circuit the first current limiting element;
When the battery pack and the integrated circuit are electrically connected, if the integrated circuit is not activated and the internal power is not supplied from the power source, the switch is turned off to turn off the switch. Charging current flows through the first current limiting element;
After the assembled battery and the integrated circuit are electrically connected and the integrated circuit is activated, when the internal power is supplied from the power source, the switch is turned on to short-circuit the current limiting element. Storage battery control device.   2. The storage battery control apparatus according to claim 1, wherein the current limiting element is inserted into a discharge circuit that is connected to the uppermost cell of the battery pack connected to the integrated circuit. 3. The storage battery control device according to claim 1, wherein a resistance value of the discharge current setting set in the discharge circuit in which the current limiting element is inserted is set to a value obtained by subtracting an impedance component of the switch circuit. A storage battery control device.

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