JP6647839B2 - Energy storage system - Google Patents

Description

  The present invention relates to a power storage system including a plurality of cells connected in series.

  In recent years, hybrid vehicles (HV), plug-in hybrid vehicles (PHV), and electric vehicles (EV) have become widespread. Lithium-ion batteries with high energy density have become widespread as power sources mounted on these vehicles. Lithium-ion batteries require more strict voltage management than other types of batteries because the normal use area and the use prohibited area are close to each other. When using an assembled battery (pack battery) in which a plurality of lithium ion battery cells are connected in series, a voltage detection circuit for detecting the voltage of each cell is provided (for example, see Patent Document 1). Each node between the plurality of cells and the voltage detection circuit are connected by a voltage detection line, and the voltage detection circuit detects the voltage between two adjacent nodes to detect the voltage of each cell.

  In this configuration, when a certain voltage detection line is broken, the voltage of the cell immediately above the node connected to the voltage detection line sticks to the upper limit, and the voltage of the cell immediately below the node sticks to the lower limit. become. Thus, when a certain voltage detection line is disconnected, the voltages of the two cells above and below the node connected to the voltage detection line cannot be detected, and the voltages of the two cells become indefinite. Conventionally, when a cell whose voltage cannot be detected occurs, a measure is taken to stop supplying power to the traveling motor.

JP 2010-127722 A

  In the case of a pure electric vehicle without an engine, stopping the power supply to the traveling motor means stopping the traveling of the vehicle. If the vehicle suddenly stops, there is a danger of a rear-end collision. Also, if the vehicle becomes unable to run on its own, it will be necessary to transport it to a car dealer or repair shop by towing or towing.

  Unlike the failure of the cell itself, the disconnection of the voltage detection line is a state in which the state of the cell cannot be confirmed, and the urgency is relatively low as compared with the case where a failure occurs in the cell itself.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a power storage system that performs a measure considering safety and convenience when a voltage detection line for detecting a voltage of a cell is disconnected. It is in.

  In order to solve the above problem, an energy storage system according to one embodiment of the present invention is connected to each node between a plurality of cells connected in series and a plurality of voltage detection lines, and detects a voltage between adjacent voltage detection lines. A voltage detecting unit for detecting the voltage of each cell, and when any one of the plurality of voltage detection lines becomes abnormal, the voltage is connected above and below the abnormal state voltage detection line from the voltage across the plurality of cells. The sum of the voltages of the remaining cells except for the two cells is subtracted, and the voltage obtained by the subtraction is halved to estimate each voltage of the two cells connected to the abnormal state voltage detection line. A control unit.

  It is to be noted that any combination of the above-described components and any conversion of the expression of the present invention between a method, an apparatus, a system, and the like are also effective as embodiments of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, when the voltage detection line for detecting the voltage of a cell is disconnected, the electric storage system which performs the treatment which considered safety and convenience can be implement | achieved.

1 is a diagram for describing a power storage system according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of an SOC-control table. FIG. 7 is a diagram illustrating a voltage behavior of the second cell and the third cell when the voltage detection line between the node between the second cell and the third cell and the voltage detection unit is disconnected according to the embodiment. FIG. 9 is a diagram illustrating a first configuration example of a second embodiment. FIG. 11 is a diagram illustrating a second configuration example of the second embodiment. FIG. 13 is a diagram illustrating a circuit configuration example of a power storage system according to a modification. It is a figure which shows the voltage behavior of a 2nd cell and a 3rd cell when the voltage detection line between the node between a 2nd cell and a 3rd cell and a voltage detection part is disconnected based on a modification.

  FIG. 1 is a diagram illustrating a power storage system 2 according to an embodiment of the present invention. In the present embodiment, an electric vehicle (EV) is assumed as the vehicle 1. The vehicle 1 includes a power storage system 2, a contactor RY, an inverter 3, a traveling motor 4, an ECU 5, an ignition switch 6, and a meter panel 7.

  Generally, a three-phase AC synchronous motor is used as the traveling motor 4. Inverter 3 is provided between traveling motor 4 and power storage system 2. During power running, the inverter 3 converts DC power supplied from the power storage system 2 into AC power and supplies the AC power to the traveling motor 4. The traveling motor 4 rotates based on the electric power supplied from the inverter 3 during power running, and causes the vehicle 1 to travel. At the time of regeneration, the traveling motor 4 generates power by rotation based on the deceleration energy of the vehicle 1 and supplies the generated power to the inverter 3. During regeneration, inverter 3 converts AC power supplied from traveling motor 4 into DC power and supplies it to power storage system 2.

  An ECU (Electronic Control Unit) 5 electronically controls the entire vehicle 1. The ECU 5 is a generic name of various ECUs in the vehicle 1 (excluding the ECU of the power storage system 2), and a plurality of ECUs operate in cooperation. The ECU 5 controls the inverter 3 based on various signals input from the accelerator pedal, the power storage system 2, various auxiliary devices, and various sensors. As a basic operation, when an accelerator pedal (not shown) is depressed, the ECU 5 controls the inverter 3 so as to supply electric power corresponding to the accelerator opening to the traveling motor 4. When the accelerator pedal is released, the ECU 5 controls the power storage system 2 to supply electric power generated by the traveling motor 4 using the deceleration energy as an energy source.

  Contactor RY is inserted between inverter 3 and power storage system 2. For example, a large relay can be used for the contactor RY. Contactor RY is an element for electrically separating power storage system 2 from the load in vehicle 1, and is controlled by control unit 40 of power storage system 2.

  The power storage system 2 includes a power storage module 10 and a management device 20. The management device 20 includes a voltage detection unit 30, a control unit 40, and a storage unit 50. Power storage module 10 includes a plurality of cells S1-Sn connected in series. The cell is configured by connecting one or more unit cells in parallel. As the cell, a lithium ion cell, a nickel hydride cell, an electric double layer capacitor cell, or the like can be used. Hereinafter, in this specification, an example in which a lithium ion cell (nominal voltage: 3.6 to 3.7 V) is used is assumed. Although one power storage module 10 (in this embodiment, a lithium-ion battery pack (also referred to as a lithium-ion battery)) is illustrated for simplicity in FIG. Thus, a plurality of power storage modules 10 are used by being connected in series.

  The voltage detection unit 30 is connected to each node between a plurality of cells S1-Sn connected in series by a plurality of voltage detection lines, detects a voltage between adjacent voltage detection lines, and detects a voltage of each cell S1-Sn. To detect. The voltage detection unit 30 is configured by, for example, an ASIC (Application Specific Integrated Circuit) that is a dedicated custom IC. The voltage detection unit 30 outputs the detected voltage of each of the cells S <b> 1 to Sn to the control unit 40.

  The control unit 40 includes an SOC estimation unit 41, a contactor control unit 42, a disconnection cell voltage estimation unit 43, and an abnormality notification unit 44. The control unit 40 is configured by, for example, a microprocessor. The storage unit 50 stores a program executed by the control unit 40 and data used in the program. The storage unit 50 includes an SOC-OCV table 51 and an SOC-control table 52.

The SOC estimating unit 41 estimates the SOC (State Of Charge) of each cell based on the detected voltage of each cell. The SOC is estimated by, for example, an OCV (Open Circuit Voltage) method. The OCV of the cell is calculated based on the voltage value V of the cell detected by the voltage detecting unit 30, the current value I of the cell detected by the current detecting unit (not shown), and the internal resistance value R of the cell (Equation 1) ).
OCV = VI-R (Equation 1)

  The SOC-OCV table 51 is a table that describes the relationship between the SOC of a cell and the OCV. There is a stable relationship between the SOC and the OCV, and the SOC can be estimated from the OCV. The SOC estimating unit 41 specifies the SOC with reference to the SOC-OCV table 51 based on the calculated OCV. The method of estimating the SOC is not limited to the above-described method. For example, a Coulomb count method may be used.

  The contactor control unit 42 controls the contactor RY based on a control signal from the ECU 5 or the SOC of the cell estimated by the SOC estimation unit 41. When the driver turns on the ignition switch 6, the ECU 5 notifies a start signal to the control unit 40, and the contactor control unit 42 closes (turns on) the contactor RY when receiving the start signal. When the driver turns off the ignition switch 6, a stop signal is notified to the control unit 40, and the contactor control unit 42 opens (turns off) the contactor RY when receiving the stop signal. Further, the contactor control unit 42 controls the contactor RY with reference to the SOC-control table 52 based on the SOC of the cell estimated by the SOC estimation unit 41.

  FIG. 2 is a diagram illustrating an example of the SOC-control table 52. In the example shown in FIG. 2, when the SOC of the cell is 80% or more, the contactor control unit 42 opens the contactor RY. When the cell is overcharged, the deterioration of the cell is accelerated, so that the contactor RY is opened so as to avoid the overcharged state. When the vehicle 1 is a pure EV, opening the contactor RY disables the vehicle 1 from traveling. In the case of a hybrid vehicle, engine running is possible.

  When the SOC of the cell is higher than 70% and lower than 80%, the control unit 40 notifies the ECU 5 of a charging prohibition signal, and the ECU 5 controls to allow powering (discharging) of the inverter 3 and prohibit regeneration (charging). . When the SOC of the cell is high, the battery is not charged even when going downhill. If the ignition is on, the contactor RY maintains the closed state.

  When the SOC of the cell is 30% or more and 70% or less, normal operation is performed. The ECU 5 controls the inverter 3 to allow both powering (discharging) and regeneration (charging). If the ignition is on, the contactor RY maintains the closed state.

  When the SOC of the cell is higher than 20% and lower than 30%, the control unit 40 notifies the ECU 5 of a discharge prohibition signal, and the ECU 5 prohibits powering (discharging) of the inverter 3 and performs control to allow regeneration (charging). . If the ignition is on, the contactor RY maintains the closed state. When the vehicle 1 is a pure EV, traveling becomes impossible. In the case of a hybrid vehicle, engine running is possible.

  When the SOC of the cell is 20% or less, the contactor control unit 42 opens the contactor RY. When the cell is over-discharged, the deterioration of the cell is accelerated, so that the contactor RY is opened so as to avoid the over-discharged state. When the vehicle 1 is a pure EV, opening the contactor RY disables the vehicle 1 from traveling. In the case of a hybrid vehicle, engine running is possible.

  The numerical values shown in the table of FIG. 2 are examples, and are not limited to the numerical examples. As the use range of the SOC is set narrower, the cell can be protected, but the traveling distance by the traveling motor 4 becomes shorter. In the case of a hybrid vehicle, since the engine can run, it is possible to set a narrow SOC use range and give priority to cell protection. In the case of a pure EV, it is required to set a wide use range of the SOC to secure a traveling distance.

  The contactor control unit 42 controls the contactor RY with reference to the SOC-control table 52 based on the SOC of each cell estimated by the SOC estimation unit 41. If at least one of the cells S1-Sn has an SOC of 20% or less or 80% or more, the contactor RY is opened.

  In the above circuit configuration, a case where one of the plurality of voltage detection lines is disconnected will be considered. Hereinafter, the case where the voltage detection line between the node between the second cell S2 and the third cell S3 and the voltage detection unit 30 is disconnected will be considered.

  FIG. 3 shows the second cell S2 and the third cell S3 when the voltage detection line between the node between the second cell S2 and the third cell S3 and the voltage detection unit 30 is broken according to the embodiment. It is a figure showing a voltage behavior. When the voltage detection line is disconnected as shown in FIG. 3, the voltage of the second cell S2 sticks to the upper limit (5 V in FIG. 3), and the voltage of the third cell S3 sticks to the lower limit (0 V in FIG. 3). As a result, the voltage of the second cell S2 and the voltage of the third cell S3 become unstable.

  Conventionally, when such a voltage behavior occurs, the contactor control unit 42 has opened the contactor RY. As a result, pure EV was stopped. However, in the case of a pure EV, sudden stoppage is dangerous, and there is a demand to continue running under certain conditions even when a failure occurs in the power storage system 2. Hereinafter, two methods for realizing this request will be described.

(Example 1)
First, a first embodiment will be described. In the first embodiment, when any of the plurality of voltage detection lines becomes abnormal in the ignition on state, the contactor control unit 42 connects the positive electrode to the cell whose negative electrode is connected to the abnormal voltage detection line. When each voltage or each SOC of the remaining cells except the two cells is within a normal range, the contactor RY is kept closed until a predetermined event occurs.

  The predetermined event corresponds to, for example, turning off the ignition switch 6. Further, the predetermined event may be a lapse of a predetermined time (for example, 24 hours) from the time of detecting the abnormality of the voltage detection line. The abnormality may be detected when the voltage detection unit 30 detects the potential loss of the voltage detection line, or the upper cell voltage of two adjacent cell voltages may stick to the upper limit and the lower cell voltage. May be at the time of sticking to the lower limit. The contactor control unit 42 opens (turns off) the contactor RY when a predetermined event occurs.

  In the above example, if all the SOCs of the first cell S1, the fourth cell S4, and the nth cell Sn except the second cell S2 and the third cell S3 are higher than 20% and lower than 80%, the contactor control unit 42 The closed state of the contactor RY is maintained. Note that the second cell S2 and the third cell S3 are treated as if they were the same as the voltage before disconnection. Accordingly, when the SOC derived from the voltage of the second cell S2 is 75%, in the example of FIG.

  The condition that the contactor control unit 42 keeps the contactor RY in the closed state includes the condition that each voltage or each SOC of the remaining cells is in a normal range, and that the SOC of the voltage (pack voltage) across the plurality of cells S1 to Sn. May be added within the normal range.

  When any one of the plurality of voltage detection lines becomes abnormal, abnormality notification unit 44 notifies ECU 5 of a signal indicating an abnormality of power storage system 2. When receiving the abnormality notification signal, ECU 5 causes meter panel 7 to display a message indicating an abnormality of power storage system 2. For example, an icon or a lamp for notifying an abnormality of the power storage system 2 is turned on. In addition, you may display on HUD (Head-Up Display) instead of the meter panel 7. FIG. The ECU 5 may output a message indicating an abnormality of the power storage system 2 from a voice output unit (not shown). At that time, when the ignition is turned off next time, a message indicating that the vehicle cannot be driven may be output together with a sound. If the time is managed, a message to the effect that the vehicle cannot be driven after the lapse of the time is output by voice.

  As described above, according to the first embodiment, even if an abnormality occurs in the voltage detection line, if the voltage or the SOC of the cells other than the two cells connected to the voltage detection line is normal, the voltage is constant. Continue running within the range. If the voltage or SOC of the other cell is normal, it is unlikely that an abnormality has occurred in the cell itself or in a path connecting the cells, and the possibility of disconnection of the voltage detection line is high. In the case of the disconnection of the voltage detection line, since the plurality of cells S1 to Sn themselves are normal, if the normal state can be maintained, there is no problem even if the traveling is continued. However, if the voltage detection line is broken, when a new abnormality occurs in the cell, there is a problem that the abnormality cannot be immediately detected.

  Therefore, in the first embodiment, the next ignition-off or traveling until a predetermined time has elapsed is permitted, and subsequent traveling is prohibited. Thereby, both safety and convenience can be achieved. In addition, when an abnormality occurs in the voltage detection line, a message indicating the occurrence of an abnormality in the power storage system 2 is displayed on the meter panel 7 so that the driver can recognize the abnormality in the power storage system 2. As a result, the driver can bring the vehicle 1 by himself / herself to a car dealer or the like before the next ignition is turned off or a predetermined time has elapsed.

(Example 2)
Next, a second embodiment will be described. In the second embodiment, when any one of the plurality of voltage detection lines becomes abnormal, the disconnected cell voltage estimating unit 43 connects the negative electrode to the abnormal voltage detection line from the voltage across the plurality of cells S1 to Sn. The sum of the voltages of the remaining cells is subtracted except for the two cells to which the cell and the positive electrode are connected. The disconnection cell voltage estimating unit 43 estimates the voltages of the two cells connected to the abnormal voltage detection line by halving the voltage obtained by the subtraction. The contactor control unit 42 controls the contactor RY using the voltage estimated by the disconnected cell voltage estimation unit 43 as the voltage of the two cells connected to the abnormal voltage detection line.

  FIG. 4 is a diagram illustrating a first configuration example of the second embodiment. The first configuration example is an example in which the voltage detection unit 30 detects the voltage between both ends (battery pack voltage VBAT-GND) of a plurality of cells S1 to Sn. The voltage detector 30 detects the battery pack voltage VBAT-GND, the voltage of the first cell S1, and the voltages of the fourth cell S4 to the nth cell Sn. The voltages of the second cell S2 and the third cell S3 are undefined. An AD converter (not shown) in the voltage detection unit 30 converts the detected value of each detected analog into a digital value.

  The voltage detector 30 adds up the voltages of the fourth cell S4 to the n-th cell Sn converted into digital values, and further adds up the voltage of the first cell S1. The voltage detector 30 subtracts the total voltage of the first cell S1, the fourth cell S4, and the n-th cell Sn from the battery pack voltage VBAT-GND. The voltage detection unit 30 estimates each voltage of the second cell S2 and the third cell S3 by halving the voltage obtained by the subtraction. The voltage detection unit 30 outputs the respective voltages of the first cell S1 to the n-th cell Sn including the estimated voltages of the second cell S2 and the third cell S3 to the control unit 40.

  Note that the battery pack voltage VBAT-GND, the voltage of the first cell S1, and the voltages of the fourth cell S4 to the nth cell Sn are output as they are from the voltage detection unit 30 to the control unit 40. May be performed.

  FIG. 5 is a diagram illustrating a second configuration example of the second embodiment. In the second configuration example, the control unit 40 detects the battery pack voltage VBAT-GND. The potential of the positive electrode of the battery pack is divided by the first voltage dividing resistor R11 and the second voltage dividing resistor R12, and is input to the AD port of the control unit 40. An AD converter (not shown) in the control unit 40 converts an analog detection value input from the AD port into a digital value.

  The voltage detector 30 detects the voltage of the first cell S1 and the voltages of the fourth cell S4 to the nth cell Sn. The voltages of the second cell S2 and the third cell S3 are undefined. The voltage detector 30 adds up the voltages of the fourth cell S4 to the n-th cell Sn, and further adds up the voltage of the first cell S1. The voltage detection unit 30 outputs the sum total voltage of the first cell S1 and the fourth cell S4 to the n-th cell Sn to the control unit 40.

  The control unit 40 subtracts the total voltage of the input first cell S1 and fourth cell S4−nth cell Sn from the detected battery pack voltage VBAT-GND, and halves the obtained voltage. The respective voltages of the second cell S2 and the third cell S3 are estimated.

  The voltage detection unit 30 detects the battery pack voltage VBAT-GND and outputs it to the control unit 40. The control unit 40 receives the battery pack voltage VBAT-GND input from the voltage detection unit 30 and inputs the battery pack voltage VBAT-GND to its own AD port. The battery pack voltage VBAT-GND may be compared. If the two do not substantially match, there is a possibility that an abnormality has occurred in the voltage detection unit 30 and / or the control unit 40.

  The contactor control unit 42 controls the contactor RY with reference to the SOC-control table 52 based on the estimated SOC of each of the cells S1 to Sn. When any one of the plurality of voltage detection lines becomes abnormal, abnormality notification unit 44 notifies ECU 5 of a signal indicating an abnormality of power storage system 2. When receiving the abnormality notification signal, ECU 5 causes meter panel 7 to display a message indicating an abnormality of power storage system 2.

  As described above, according to the second embodiment, when an abnormality occurs in the voltage detection line, the abnormality is determined based on the voltage of the cell other than the two cells connected to the voltage detection line and the battery pack voltage. The voltage of two cells connected to the voltage detection line is estimated. If the voltages or SOCs of the two cells are normal, it is unlikely that an abnormality has occurred in the cell itself or in a path connecting the cells, and there is a high possibility that the voltage detection line is disconnected. In the case of the disconnection of the voltage detection line, since the plurality of cells S1 to Sn themselves are normal, if the normal state can be maintained, there is no problem even if the traveling is continued.

  In the second embodiment, instead of using the previous values as the voltages of the two cells as in the first embodiment, estimation is performed based on the voltages of the other cells and the pack voltage. Therefore, it can be said that the monitoring level of the two cells is higher than that of the first embodiment. Therefore, there is no need to restrict the vehicle from running when the ignition is turned off or after a certain period of time as in the first embodiment.

  In addition, when an abnormality occurs in the voltage detection line, a message indicating the occurrence of an abnormality in the power storage system 2 is displayed on the meter panel 7 so that the driver can recognize the abnormality in the power storage system 2. Thus, the driver can bring the vehicle 1 by himself / herself.

  The present invention has been described based on the embodiments. These embodiments are exemplifications, and it is understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and that such modifications are also within the scope of the present invention. is there.

  FIG. 6 is a diagram illustrating a circuit configuration example of a power storage system 2 according to a modification. In the modified example, the resistors R1 to Rn (high resistance) are respectively connected between the plurality of voltage detection lines. As shown in FIG. 6, when the voltage detection line between the node between the second cell S2 and the third cell S3 and the voltage detection unit 30 is disconnected, the second resistor R2 connected to the voltage detection line The voltage between the voltage detection line one immediately above and the voltage detection line one below is divided by the three resistors R3. Therefore, the potential of the disconnected voltage detection line is maintained at the midpoint potential of the voltage between the upper and lower voltage detection lines.

  The resistors R1 to Rn are examples of the impedance element, and another impedance element may be used. For example, transistors may be connected instead of the resistors R1 to Rn, and the on-resistance of the transistors may be used.

  FIG. 7 shows the voltages of the second cell S2 and the third cell S3 when the voltage detection line between the node between the second cell S2 and the third cell S3 and the voltage detection unit 30 is broken, according to the modification. It is a figure showing a behavior. As shown in FIG. 7, even when the voltage detection line is disconnected, the voltage of the second cell S2 and the voltage of the third cell S3 are maintained at substantially the same voltage as the voltage before disconnection (3.7 V). The contactor control unit 42 controls the contactor RY with reference to the SOC-control table 52 based on the detected SOC of each of the cells S <b> 1 to Sn as before the disconnection.

  In the circuit configuration shown in FIG. 6, the abnormality of the voltage detection line cannot be detected immediately. In order to immediately detect the abnormality of the voltage detection line, for example, a phase may be provided in which a switch is connected in series to each of the resistors R1 to Rn, and all of the plurality of switches are turned off. When all the switches are off, the circuit configuration is the same as in FIGS. 1, 4 and 5, and the disconnection of the voltage detection line can be detected immediately.

  In the above-described second embodiment and the modified example, the restriction that the driving is disabled due to the ignition-off or the fixed time elapse as in the first embodiment after the abnormality detection of the voltage detection line is not imposed. Such restrictions may be imposed. In this case, the driver can be reliably encouraged to repair the power storage system 2.

  The embodiment may be specified by the following items.

[Item 1]
Each node between a plurality of cells (S1-Sn) connected in series is connected to a plurality of voltage detection lines, and a voltage between adjacent voltage detection lines is detected to detect a voltage of each cell (S1-Sn). A voltage detector (30);
When one of the plurality of voltage detection lines becomes abnormal, two cells (S2, S3) connected above and below the abnormal voltage detection line from the voltage across the plurality of cells (S1-Sn). Are subtracted from each other, and the voltage obtained by the subtraction is reduced to half, and the two cells (S2) connected to the abnormal state voltage detection line are reduced. , S3) a control unit (40) for estimating each voltage;
A power storage system (2), comprising:
According to this, the voltage of the cell connected to the voltage detection line in the abnormal state can be estimated with relatively high accuracy.
[Item 2]
The power storage system (2) is mounted on a vehicle (1), and is connected to a traveling motor (4) via a contactor (RY) in the vehicle (1).
The control section (40) controls the contactor (RY) to be in a closed state when each voltage or each SOC (State Of Charge) of the plurality of cells (S1-Sn) is within a normal range in an ignition on state. And controlling the contactor (RY) to be open when the voltage or the SOC of at least one of the cells (S2, S3) is abnormal;
When one of the plurality of voltage detection lines becomes abnormal, the control unit (40) determines the estimated voltage as the voltage of two cells (S2, S3) connected to the abnormal voltage detection line. The power storage system (2) according to item 1, wherein the contactor (RY) is controlled using a power supply.
According to this, even if the voltage detection line is broken, the state in which the vehicle (1) can travel can be maintained as much as possible.
[Item 3]
A power storage system (2) mounted on a vehicle (1) and connected to a traveling motor (4) via a contactor (RY) in the vehicle (1),
Each node between a plurality of cells (S1-Sn) connected in series is connected to a plurality of voltage detection lines, and a voltage between adjacent voltage detection lines is detected to detect a voltage of each cell (S1-Sn). A voltage detector (30);
In the ignition on state, when each voltage or each SOC (State Of Charge) of the plurality of cells (S1-Sn) is within a normal range, the contactor (RY) is controlled to a closed state, and at least one cell (S2) is controlled. , S3) a control unit that controls the contactor (RY) to be in an open state when the voltage or the SOC is abnormal.
When one of the plurality of voltage detection lines becomes abnormal in the ignition-on state, the control unit (40) connects two cells (S2, S3) to be connected above and below the abnormal state voltage detection line. When each voltage or each SOC of the remaining cells (S1, S4-Sn) is within a normal range, the contactor (RY) is kept closed until a predetermined event occurs. System (2).
According to this, even if the voltage detection line is disconnected, the state in which the vehicle (1) can travel can be maintained as much as possible.
[Item 4]
The power storage system (2) according to item 3, wherein the predetermined event is ignition off.
According to this, both safety and convenience can be achieved.
[Item 5]
When any one of the plurality of voltage detection lines becomes abnormal, the control unit (40) sends a signal indicating abnormality of the voltage detection lines of the power storage system (2) to an ECU (ECU) in the vehicle (1). The power storage system (2) according to any one of items 2 to 4, wherein the power storage system (2) is notified to an electronic control unit (5).
According to this, the abnormality of the power storage system (2) can be notified to the vehicle side and the driver.
[Item 6]
A power storage system (2) mounted on a vehicle (1) and connected to a traveling motor (4) via a contactor (RY) in the vehicle (1),
Each node between a plurality of cells (S1-Sn) connected in series is connected to a plurality of voltage detection lines, and a voltage between adjacent voltage detection lines is detected to detect a voltage of each cell (S1-Sn). A voltage detector (30);
An impedance element (R1-Rs) connected between each of the plurality of voltage detection lines;
In the ignition on state, when each voltage or each SOC (State Of Charge) of the plurality of cells (S1-Sn) is within a normal range, the contactor (RY) is controlled to a closed state, and at least one cell (S2) is controlled. , S3) a control unit that controls the contactor (RY) to open when the voltage or SOC is abnormal;
A power storage system (2), comprising:
According to this, even if the voltage detection line is broken, the state in which the vehicle (1) can travel can be maintained as much as possible.

  Reference Signs List 1 vehicle, 2 power storage system, 3 inverter, 4 traveling motor, 5 ECU, 6 ignition switch, 7 meter panel, 10 power storage module, 20 management device, S1 first cell, S2 second cell, S3 third cell, S4 4th cell, Sn nth cell, 30 voltage detection unit, 40 control unit, 41 SOC estimation unit, 42 contactor control unit, 43 disconnection cell voltage estimation unit, 44 abnormality notification unit, 50 storage unit, 51 SOC-OCV table, 52 SOC-control table, RY contactor, R1 first resistor, R2 second resistor, R3 third resistor, Rn nth resistor, R11 first voltage dividing resistor, R12 second voltage dividing resistor.

Claims (2)

A power storage system mounted on a vehicle and connected to a traveling motor via a contactor in the vehicle,
Each node between a plurality of cells connected in series and a plurality of voltage detection lines are connected, a voltage between adjacent voltage detection lines is detected to detect a voltage of each cell, and the plurality of voltage detection lines are connected. A voltage detection unit connected to a node located at both ends of the plurality of cells among a plurality of nodes by a pair of detection lines, and detects a voltage between the pair of detection lines to detect a voltage between both ends of the plurality of cells;
In the ignition-on state, each voltage or each SOC (State Of
And a control unit that controls the contactor to be in a closed state when Charge is within a normal range, and controls the contactor to be in an open state when the voltage or SOC of at least one cell is abnormal.
The control unit is configured to receive a potential of the positive electrode of the plurality of cells divided by the first voltage dividing resistor and the second voltage dividing resistor, and to detect a voltage between both ends of the plurality of cells detected from the inputted potential and the voltage. The voltage detection circuit compares the voltage across the plurality of cells detected by the voltage detection circuit to determine the abnormality of the voltage detection unit and / or the control unit,
The control unit is configured such that, when any one of the plurality of voltage detection lines becomes abnormal, the remaining cells excluding two cells connected above and below the abnormal state voltage detection line from the voltage across the plurality of cells. each voltage sum is subtracted, and then the voltage obtained by subtracting the half estimates the respective voltages of the two cells connected to the voltage detection lines of the abnormal state, each cell by the voltage detection unit of And controlling the contactor using the estimated voltage as the voltage of two cells connected to a voltage detection line in an abnormal state. system. The control unit, when any one of the plurality of voltage detection lines becomes abnormal, notifies a signal indicating abnormality of the voltage detection lines of the power storage system to an ECU (Electronic Control Unit) in the vehicle. The power storage system according to claim 1 , wherein:

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