JP2015070653A - Battery voltage equalization control device and method - Google Patents

Abstract

When equalizing the voltage of each battery cell of a battery module, control is performed so that the voltage is equalized more appropriately in accordance with the operating state of a vehicle. A voltage equalization control unit (10) equalizes the voltage of each battery cell by passing a current between the battery cells to battery cells connected in series in a battery module (40). The charge / discharge state determination unit 101 determines whether the battery module 40 is being charged / discharged or is not being charged / discharged, and the voltage equalization control unit 102 determines whether each battery cell has When the current is passed between the battery cells so that the observed voltage reaches the overall average voltage of the battery cells, and the battery module 40 is in a charge / discharge stop state, the observed voltage of each battery cell is the average of the entire battery cells. After reaching the voltage, the equalization operation is further switched so that a current flows between the battery cells until the voltage reaches a voltage separated from the average voltage by a voltage fluctuation due to the internal resistance or polarization action of each battery cell. [Selection] Figure 1

Description

  The present invention relates to a battery voltage equalization control apparatus and method for controlling a battery voltage equalization operation for equalizing voltages of a plurality of rechargeable battery cells connected in series.

  A battery module in which a plurality of rechargeable battery cells such as lithium ion batteries are connected in series to obtain a high voltage output is used for vehicles such as forklifts, electric vehicles, and hybrid vehicles. A battery module mounted on a vehicle or the like is frequently repeatedly charged with a regenerative current when discharging a load circuit such as a motor during vehicle operation and when the vehicle decelerates.

  Battery cells have different characteristics such as remaining capacity and charging efficiency due to variations in manufacturing and aging deterioration, etc., and the remaining capacity and voltage of each battery cell vary due to repeated charging and discharging, and each battery cell has different characteristics. The voltage is uneven.

  In a battery module in which battery cells are connected in series, if the voltage of each battery cell becomes non-uniform, when charging / discharging the battery module, the upper limit voltage at which some of the battery cells can be charged or the lower limit voltage at which discharge can be performed. As a result, deterioration of some battery cells is accelerated.

  Further, when the voltage of one battery cell falls below the threshold value of the dischargeable voltage, it is necessary to stop or suppress the power supply of the entire battery module in order to avoid overdischarge of the battery cell. Will fall. Therefore, battery voltage equalization is performed to equalize the voltage of each battery cell of the battery module.

  As a battery voltage equalization circuit, a voltage equalization circuit called an active cell balance is known in which a current flows from a battery cell having a high voltage to a battery cell having a low voltage to equalize the voltage of each battery cell.

  FIG. 4 shows a basic configuration example of an active cell balance voltage equalization circuit. As shown in FIG. 4, the active cell balance voltage equalization circuit connects the switch elements HS and LS connected in series to the battery cells B1 and B2 connected in series. Then, one end of the inductor L is connected to the connection point of the battery cells B1 and B2, and the other end of the inductor L is connected to the connection point of the switch elements HS and LS.

  The diodes HD and LD are built-in diodes formed between the source and drain of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) used for the switch elements HS and LS, and are called body diodes or parasitic diodes.

  In such a voltage equalization circuit, when the voltage of the battery cell B1 is higher than the voltage of the battery cell B2, a gate signal HG for turning on the switch element HS is given, and a gate signal LG for turning off the switch element LS is given. Then, a closed loop current path of battery cell B1 → switch element HS → inductor L → battery cell B1 is formed, and a predetermined amount of current flows from battery cell B1 to inductor L.

  Thereafter, when the switch element HS is turned off and the switch element LS is turned on, a closed loop current path of inductor L → battery cell B2 → switch element LS → inductor L is formed, and a predetermined amount of current flowing through the inductor L is supplied to the battery cell. It flows to B2. By repeating such an operation, the voltage of the battery cell B1 and the voltage of the battery cell B2 are equalized.

  Conversely, when the voltage of the battery cell B2 is higher than the voltage of the battery cell B1, a gate signal LG for turning on the switch element LS is given, and a gate signal HG for turning off the switch element HS is given. Then, a closed loop current path of battery cell B 2 → inductor L → switch element LS → battery cell B 2 is formed, and a predetermined amount of current flows from battery cell B 2 to inductor L.

  Thereafter, when the switch element LS is turned off and the switch element HS is turned on, a closed loop current path of inductor L → switch element HS → battery cell B1 → inductor L is formed, and the current flowing through the inductor L flows into the battery cell B1. Flowing. By repeating such an operation, the voltage of the battery cell B1 and the voltage of the battery cell B2 are equalized.

  However, each battery cell has an internal resistance or polarization effect that causes a voltage fluctuation in the output voltage due to the current when the current flows. Here, “internal resistance or polarization action” means “both internal resistance and polarization action” or “any one of internal resistance or polarization action”, and in the following, in order to simplify the explanation, It is described as “internal resistance or polarization action”.

  When voltage equalization of each battery cell is performed for each battery cell using the average voltage of each battery cell as a target voltage, the voltage observed as the voltage of each battery cell is the closed circuit voltage (CCV: Closed Circuit Voltage).

  The closed circuit voltage (CCV) of each battery cell observed in the battery voltage equalization is the original output of each battery cell by the amount of voltage fluctuation due to internal resistance or polarization caused by the charge / discharge current between the battery cells. The voltage is shifted from the open circuit voltage (OCV) which is a voltage.

  FIG. 5 shows an example of the battery voltage equalization operation in which the voltage is shifted by the amount of voltage fluctuation due to internal resistance or polarization. The operation example shown in FIG. 5 is an operation example in which the voltage of the battery cell B1 is higher than the voltage of the battery cell B2, the current is passed from the battery cell B1 to the battery cell B2, and the voltages of the battery cell B1 and the battery cell B2 are equalized. Show.

  When the battery voltage equalization operation is started, the closed circuit voltage CCV1 of the battery cell B1 that is discharged to the battery cell B2 is a voltage that is reduced from the open circuit voltage OCV1 by a voltage variation ΔV1 due to the influence of internal resistance or polarization action. . On the other hand, the closed circuit voltage CCV1 of the battery cell B2 charged from the battery cell B1 is a voltage increased from the open circuit voltage OCV2 by a voltage variation ΔV2 due to the influence of internal resistance or polarization action.

  While observing the closed circuit voltage CCV1 of the battery cell B1 and the closed circuit voltage CCV2 of the battery cell B2, the voltage equalization is performed until the time t1 when both reach the vicinity of the average voltage that is the target voltage. When the voltage equalization operation ends, the charging / discharging current for voltage equalization stops flowing after time t1, so that the voltage fluctuation due to the internal resistance or polarization caused by the charging / discharging current is eliminated, and time t1 Thereafter, the open circuit voltages OCV1a and OCV2a of the battery cells B1 and B2 approach the original open circuit voltages OCV1 and OCV2, respectively. The voltage deviates from the average voltage which is the target voltage.

  When the voltage variation is caused only by the internal resistance and there is no voltage variation due to the polarization action, the open circuit voltages OCV1a and OCV2a of the battery cells B1 and B2 are respectively the original open circuit voltage OCV1 at time t1. , OCV2.

  Therefore, for a battery cell that equalizes the voltage, an offset voltage, which is a voltage fluctuation due to the internal resistance or polarization action of the battery cell, is calculated, and the target voltage for voltage equalization is corrected by the offset voltage. A voltage equalization that performs voltage equalization until the voltage of the battery cell reaches the corrected target voltage while observing the voltage of the cell is known from, for example, Patent Document 1 below.

  FIG. 6 shows an operation example of battery voltage equalization in which the target voltage is corrected by the offset voltage. In the operation example shown in FIG. 6, the voltage of the battery cell B1 is higher than the voltage of the battery cell B2, and the current flows from the battery cell B1 to the battery cell B2, as in the operation example of FIG. The operation example which equalizes the voltage of is shown.

  In the operation example of FIG. 6, the operation up to the time point t1 is the same as the operation example shown in FIG. In the operation example shown in FIG. 5, the voltage equalization operation is terminated at time t1, but in the operation example of FIG. 6, the voltage equalization operation is not terminated at time t1 until the time t1a described later. Continue the equalization operation.

  In the operation example of FIG. 6, offset voltages OFS1 and OFS2, which are voltage fluctuations due to the internal resistance or polarization action of the battery cells B1 and B2, are calculated, and the target voltage for voltage equalization is corrected by the offset voltages OFS1 and OFS2. .

  That is, for the battery cell B1, the target voltage is corrected to a voltage lower than the average voltage by the offset voltage OFS1 as the target voltage for ending the voltage equalization. For the battery cell B2, the target voltage is corrected to a voltage higher than the average voltage by the offset voltage OFS2 as the target voltage for ending the voltage equalization.

  While observing both or one of the closed circuit voltages CCV1 and CCV2 of the battery cells B1 and B2, voltage equalization is performed until a time point t1a that reaches the vicinity of the target voltage corrected by the offset voltages OFS1 and OFS2. The voltage equalization operation ends at time t1a.

  When the charging / discharging current for equalizing voltage stops flowing after time t1a, the voltage fluctuation due to internal resistance or polarization caused by the charging / discharging current is eliminated, and the battery cells B1, B2 after time t1a are opened. The circuit voltages OCV1a and OCV2a become voltages close to the average voltage, which is the target voltage before correction, at time t2 after the elimination of polarization.

  When the voltage fluctuation is caused only by the internal resistance and there is no voltage fluctuation due to the polarization action, the open circuit voltages OCV1a and OCV2a of the battery cells B1 and B2 are the target voltages before correction at time t1a. It becomes a certain average voltage.

  The operation example of the battery voltage equalization of the battery cell shown in FIG. 5 and FIG. 6 described above is performed when each battery is charged and discharged when no charge / discharge current flows between the battery cell and an external device that is a load circuit such as a vehicle. An operation example of battery voltage equalization when voltage equalization between cells is performed is shown.

  On the other hand, when the charging / discharging current does not flow between the battery module and the external device, the discharge circuit is operated, the voltage of the battery cell is equalized in the first equalization mode, and the external device is A control device for a power storage device that operates a discharge circuit and performs voltage equalization of battery cells in the second equalization mode when the charge / discharge current flows and the voltage difference between the battery cells is larger than a threshold value is described below. Known from document 2.

JP 2013-102592 A JP 2012-165580 A

  When voltage equalization of each battery cell is performed with an active cell balance voltage equalization circuit, a large current charge / discharge current is passed between the battery cells to equalize the voltage. Even if voltage fluctuation due to resistance or polarization occurs, as shown in FIG. 6, the target voltage is corrected as an offset voltage by the voltage fluctuation due to internal resistance or polarization, and the battery voltage is equalized. The accuracy of battery voltage equalization can be improved.

  However, when performing the battery voltage equalization by correcting the target voltage as the offset voltage by the amount of voltage fluctuation due to the internal resistance or polarization action, the load circuit such as the motor of the vehicle or the external device such as the charger and the battery cell When the charge / discharge current is flowing between the two, the voltage fluctuation due to internal resistance or polarization action is the voltage fluctuation due to the charge / discharge current for equalizing the voltage between the battery cells. Since a voltage fluctuation due to current is added, it is difficult to calculate an offset voltage for correcting the target voltage.

  Furthermore, the transition of the operating state of the vehicle varies depending on the usage method of the user, and the fluctuation of the charging / discharging current of each battery cell due to the operation of the vehicle is not uniform, so the offset voltage when the vehicle is operating is not uniform. It is difficult to calculate the offset voltage when the vehicle is in operation.

  When a charge / discharge current is flowing between the battery module and the external device, if the target voltage is corrected with the offset voltage calculated incorrectly and the battery voltage equalization is performed, the offset voltage will be the actual internal resistance or polarization. Since it is different from the voltage fluctuation due to the action, the battery cell voltage variation may spread before the battery voltage equalization.

  In view of the above problems, the present invention can control the voltage of each battery cell to be more appropriately equalized according to the operating state of the vehicle even when the user uses the vehicle in various ways. A battery voltage equalization control device and method are provided.

  A battery voltage equalization control device as one embodiment according to the present invention constitutes a battery module, observes the voltage of each battery cell with respect to battery cells connected in series, and supplies a current between the battery cells. A battery voltage equalization control device for equalizing the voltage of each battery cell, wherein the battery module is being charged or discharged from an external device or discharged to the external device, or Charging / discharging state determination means for determining whether charging / discharging is stopped between, and the battery module according to the charging / discharging state of the battery module determined by the charging / discharging state determination means Voltage equalization control means for switching the operation of equalizing the voltage of the cells, and the voltage equalization control means is configured such that when the battery module is in the charge / discharge state, the observed voltage of each battery cell is ,Previous Each battery cell is controlled so that a current is passed between the battery cells to equalize the voltage until the overall average voltage of the battery cells is reached, and when the battery module is in the charge / discharge stop state. Between the battery cells until the observed voltage of the battery cell reaches an average voltage of the whole battery cell, and further reaches a voltage separated from the average voltage by a voltage fluctuation due to an internal resistance or polarization action of each battery cell. The control is performed so as to equalize the voltage by supplying a current.

  According to the present invention, according to the charging / discharging state of the battery module, by switching the operation of equalizing the voltage of each battery cell of the battery module, in accordance with the operating state of the vehicle or the like in which the battery module is used, more It is possible to appropriately equalize the voltage of each battery cell and improve the accuracy of equalizing the voltage of each battery cell.

It is a figure which shows the example of arrangement structure of a battery pack provided with the battery voltage equalization control apparatus, and a vehicle monitoring unit. It is a figure which shows the specific structural example of a voltage equalization unit and battery monitoring ECU. It is a figure which shows the example of an operation | movement flow of battery voltage equalization control. It is a figure which shows the basic structural example of the voltage equalization circuit of an active cell balance. It is a figure which shows the operation example of the battery voltage equalization shifted | deviated by the voltage fluctuation | variation by internal resistance or a polarization effect. It is a figure which shows the operation example of the battery voltage equalization which correct | amended the target voltage with the offset voltage.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an arrangement configuration example of a battery pack equipped with a battery voltage equalization control device of the present invention and an electronic control unit (ECU) for vehicle monitoring. Hereinafter, the electronic control unit is simply referred to as an ECU, and the vehicle monitoring ECU is referred to as a vehicle monitoring ECU.

  The battery pack 50 includes a battery module 40 having battery cells connected in series, a voltage equalization unit 10 that equalizes the voltages of the battery cells of the battery module 40, an ECU 20 for battery monitoring, and an ECU 30 for battery control.

  Hereinafter, the battery monitoring ECU 20 is referred to as a battery monitoring ECU 20, the battery control ECU 30 is referred to as a battery control ECU 30, and the battery monitoring ECU, the battery control ECU, and the vehicle monitoring ECU are referred to as a battery monitoring unit, a battery control unit, and a battery monitoring ECU, respectively. Also called vehicle monitoring unit.

  The voltage equalization unit 10 includes a charge / discharge state determination unit 101 and a voltage equalization control unit 102, and is connected to the battery monitoring ECU 20 via a communication line C1 such as CAN (Controller Area Network) communication. Is obtained, and the voltage between the battery cells is equalized.

  The battery monitoring ECU 20 includes a microcontroller, observes the voltage of each battery cell, and transmits the voltage of each battery cell to the voltage equalization unit 10 via the communication line C1. The battery monitoring ECU 20 is connected to a battery control ECU 30 that is a host control unit via a communication line C2 such as CAN communication.

  The battery control ECU 30 is connected to a vehicle monitoring ECU 60 that monitors the operation state of the vehicle via a communication line C4 such as CAN communication, and receives vehicle operation state information from the vehicle monitoring ECU 60. The battery monitoring ECU 20 acquires vehicle operating state information from the battery control ECU 30 via a communication line C2 such as CAN communication.

  Further, the voltage equalization unit 10 is connected to the battery control ECU 30 via a communication line C3 such as CAN communication, and obtains vehicle operating state information from the battery control ECU 30 via the communication line C3 such as CAN communication. Alternatively, the voltage equalization unit 10 may be configured to acquire the vehicle operating state information from the battery monitoring ECU 20 via the communication line C1.

  The battery module 40 is connected to a load circuit such as a motor of a vehicle (not shown) driven by the battery pack 50 or an external device such as a charger, and is discharged or charged. The charge / discharge state determination unit 101 of the voltage equalization unit 10 is performing charging / discharging in which the battery module 40 is charged from the external device or discharged to the external device, or stops charging / discharging with the external device. Whether charging / discharging is stopped is determined based on the vehicle operating state information from the vehicle monitoring ECU 60.

  The voltage equalization control unit 102 of the voltage equalization unit 10 changes the battery cell voltage equalization operation mode as follows according to the charge / discharge state of the battery module 40 determined by the charge / discharge state determination unit 101. Switch automatically.

  When the battery module 40 is in a state of being charged / discharged, the voltage equalization control unit 102 supplies current between the battery cells until the observation voltage of each battery cell reaches the overall average voltage (target voltage) of the battery cells. In the first operation mode in which the equalization of the battery voltage is terminated when the voltage of each battery cell reaches the average voltage (target voltage) of the entire battery cell. Control to perform equalization.

  On the other hand, when the battery module 40 is in a charge / discharge stop state, the voltage equalization control unit 102 further increases the average after the observation voltage of each battery cell reaches the average voltage (target voltage) of the entire battery cell. Until the voltage reaches a voltage (target voltage corrected by the offset voltage) that is separated from the voltage by the voltage fluctuation (offset voltage) due to the internal resistance or polarization action of each battery cell, current flows between the battery cells and the voltage of each battery cell. And the battery voltage equalization is controlled in the second operation mode in which the equalization of the battery voltage is terminated when the voltage of the battery cell reaches the target voltage corrected by the offset voltage.

  That is, when the vehicle is in operation and a discharge current flows from the battery module 40 to the load circuit or the battery module 40 is charged from an external charger, the voltage equalization control unit 102 observes each battery cell. The battery voltage is equalized in the first operation mode while charging / discharging between the battery cells so that the closed circuit voltage (CCV) as the voltage reaches the target voltage (average voltage of the battery cells). However, in this case, the average voltage (target voltage) of the entire battery cell is not flat as shown in FIG. 5, and varies with time according to the operating state of the vehicle.

  On the other hand, when the vehicle is stopped and there is no discharge from the battery module 40 to the load circuit and the battery module 40 is not charged from an external charger, the voltage equalization control unit 102 is shown in FIG. As described above, the battery voltage is equalized in the second operation mode so that the voltage equalization is performed by correcting the target voltage for voltage equalization by the offset voltage separated by the voltage fluctuation due to the internal resistance or polarization action of each battery cell. Turn into.

  FIG. 2 shows a specific configuration example of the voltage equalization unit and the battery monitoring ECU. The voltage equalization unit 10 includes a power unit 11, a digital control unit 12, and an analog control unit 13. The power unit 11 includes, for example, 13 voltage equalization circuits that allow current to flow between two adjacent battery cells with respect to the battery module 40 including 14 battery cells.

  Each voltage equalization circuit includes two switch elements and an inductor L as described with reference to FIG. Gate signals HG and LG are applied to the two switch elements, respectively, and current is passed between two adjacent battery cells via the inductor L by turning on / off the switch elements to equalize the voltages. In FIG. 2, suffixes A to M are attached to the elements such as the gate signals HG and LG and the inductor L in the 13 voltage equalizing circuits, corresponding to the respective voltage equalizing circuits.

  The voltage of each battery cell is input to the battery monitoring IC 21 of the battery monitoring ECU 20, converted into a digital signal by the analog-digital converter 211, and the voltage of the digital control unit 12 in the voltage equalization unit 10 from the battery monitoring microcontroller 22. The voltage information is sent to the equalization microcontroller 121.

  The voltage equalization microcontroller 121 determines whether each voltage is equalized based on the voltage information of each battery cell depending on whether the operation mode for equalizing the battery voltage is the first operation mode or the second operation mode. The control signals C1A, C2A to C1M, C2M for controlling on / off of the two switch elements of the conversion circuit are sent to each analog IC corresponding to each voltage equalization circuit of the analog control unit 13. Each analog IC generates gate signals HGA, LGA to HGM, and LGM for turning on / off the two switch elements of each voltage equalization circuit in accordance with the control signals C1A, C2A to C1M, and C2M.

  Each voltage equalization circuit includes current detection units DA to DM that detect currents flowing through the voltage equalization circuits, and detection signals from the current detection units DA to DM are sent to the voltage equalization microcontroller 121. The voltage equalization microcontroller 121 receives the detection signals of the current detection units DA to DM and the voltage information of each battery cell detected by the battery monitoring IC 21 of the battery monitoring ECU 20 and notified by the battery monitoring microcontroller 22.

  The stop signals SA to SM are applied to analog ICs (gate signal generation units) corresponding to the voltage equalization circuits of the analog control unit 13, and the analog ICs (gate signal generation units) receive stop signals SA to SM. Then, gate signals HGA, LGA to HGM, LGM for turning off the two switch elements of the voltage equalization circuit are output to stop the operation of the voltage equalization circuit.

  FIG. 3 shows an example of an operation flow of battery voltage equalization control. The charging / discharging state determination unit 101 is performing charging / discharging in which the battery module 40 is charged from an external device or discharged to the external device, or charging / discharging is stopped with the external device. Information on the vehicle operating state indicating whether the vehicle is inside is acquired from the vehicle monitoring ECU 60 via the battery control ECU 30 (step S1).

  The charge / discharge state determination unit 101 determines the charge / discharge state of the battery module 40 based on the vehicle operating state information (step S2). Based on the determination result, when the battery module 40 is performing charging / discharging, the voltage equalization control unit 102 determines whether the observation voltage of each battery cell reaches the average voltage (target voltage) of the entire battery cell. Control is performed so as to equalize the voltage of each battery cell by passing a current between the cells (step S3).

  On the other hand, when the battery module 40 is in a charge / discharge stop state, the voltage equalization control unit 102 further increases the average voltage (target voltage) after the observation voltage of each battery cell reaches the overall average voltage (target voltage) of the battery cells. Control is performed so as to equalize the voltage of each battery cell by passing a current between the battery cells until reaching a voltage that is separated from the target voltage by a voltage variation due to the internal resistance or polarization action of each battery cell (step S4). ).

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment described above, In the range which does not deviate from the summary of this invention, various structures or embodiment can be taken. it can.

  For example, regarding the charge / discharge state determination unit 101 of the voltage equalization unit 10, the battery monitor ECU 20 observes the charge / discharge state of the battery module 40 instead of the configuration for determining the vehicle operation state information from the vehicle monitor ECU 60. Based on the charging / discharging current of each battery cell, the battery module 40 is being charged / discharged from the external device or discharged to the external device, or charging / discharging is stopped with the external device. It is good also as a structure which determines whether it is charging / discharging stopping.

  Further, the voltage equalization control unit 102 of the voltage equalization unit 10 determines whether or not the voltage equalization of each battery cell of the battery module 40 is necessary based on the voltage information of each battery cell acquired from the battery monitoring ECU 20. Instead of the configuration to be performed, the battery monitoring ECU 20 may determine the configuration.

  Further, whether or not voltage equalization of each battery cell of the battery module 40 is necessary is determined by both the voltage equalization unit 10 and the battery monitoring ECU 20, and based on the determination result of both voltage equalization necessity, A determination may be made as to whether or not voltage equalization of the battery cell is necessary, and when voltage equalization of the battery cell is required, the voltage equalization control unit 102 may control the voltage equalization of the battery cell.

  Here, whether or not the battery voltage equalization is necessary is determined when the voltage equalization unit 10 and the battery monitoring ECU 20 both determine that the voltage equalization is necessary. When either one of the control unit 10 or the battery monitoring ECU 20 determines that voltage equalization is necessary, it can be determined that voltage equalization is necessary.

  As described above, the determination of whether or not the battery voltage needs to be equalized is performed by both the voltage equalizing unit 10 and the battery monitoring ECU 20, whereby the operation for determining whether or not the battery voltage is equalized is duplicated. The reliability of operation can be improved.

  Furthermore, while determining the charging / discharging state of the battery module 40 based on the vehicle operating state information from the vehicle monitoring ECU 60, charging / discharging is being performed based on the charging / discharging current of each battery cell observed by the battery monitoring ECU 20. By determining whether or not charging / discharging is stopped, the determination operation of the charge / discharge state of the battery module 40 is duplicated, and the reliability of the determination of the operation mode of battery voltage equalization can be improved.

DESCRIPTION OF SYMBOLS 10 Voltage equalization unit 101 Charging / discharging state determination part 102 Voltage equalization control part 20 Battery monitoring ECU
30 Battery control ECU
40 battery module 50 battery pack 60 vehicle monitoring ECU
Communication lines such as C1, C2, C3, C4 CAN communication

Claims (5)

A battery voltage equalization control device that configures a battery module, observes the voltage of each battery cell with respect to battery cells connected in series, flows current between the battery cells, and equalizes the voltage of each battery cell Because
Charging to determine whether the battery module is being charged / discharged from an external device or discharged to the external device, or whether charging / discharging is being stopped with an external device. Discharge state determination means;
Voltage equalization control means for switching the voltage equalization operation of the battery cells in accordance with the charge / discharge state of the battery module determined by the charge / discharge state determination means;
With
When the battery module is in a state of being charged / discharged, the voltage equalization control unit is configured to supply a current between the battery cells until an observation voltage of each battery cell reaches an average voltage of the battery cells. When the battery module is in the charge / discharge stop state, the observed voltage of each battery cell reaches the average voltage of the entire battery cell, Further, control is performed so as to equalize the voltage by passing a current between the battery cells until reaching a voltage separated from the average voltage by a voltage fluctuation due to an internal resistance or polarization action of each battery cell. Battery voltage equalization control device.   Whether the battery module is performing the charge / discharge based on the vehicle operating state information acquired from a vehicle monitoring unit that monitors an operating state of a vehicle driven by the battery module. 2. The battery voltage equalization control device according to claim 1, wherein whether or not charging / discharging is stopped is determined.   The charging / discharging state determination means determines whether the battery module is performing the charging / discharging or stopping charging / discharging based on a charging / discharging current of each battery cell observed by the battery monitoring unit. The battery voltage equalization control device according to claim 2. A battery monitoring unit for observing the voltage of each battery cell;
A voltage equalization unit that receives the voltage of each battery cell from the battery monitoring unit and flows current between the battery cells to equalize the voltage of each battery cell;
With
Both the voltage equalization unit and the battery monitoring unit determine whether or not the voltage equalization is necessary, and based on the result of the determination of whether or not the voltage equalization is necessary, the voltage equalization of the battery cell The voltage equalization control means controls the voltage equalization of the battery cell when the voltage equalization of the battery cell is necessary, and the voltage equalization control means controls the voltage equalization of the battery cell. A battery voltage equalization control device according to claim 1. Battery voltage equalization control method for configuring battery modules and observing the voltage of each battery cell with respect to battery cells connected in series, flowing current between the battery cells, and equalizing the voltage of each battery cell Because
Charging to determine whether the battery module is being charged / discharged from an external device or discharged to the external device, or whether charging / discharging is being stopped with an external device. Discharge state determination process;
A voltage equalization control process for switching the voltage equalization operation of the battery cell according to the charge / discharge state of the battery module determined by the charge / discharge state determination process;
Including
In the voltage equalization control process, when the battery module is in the charging / discharging state, the current between the battery cells is changed until the observation voltage of each battery cell reaches the average voltage of the entire battery cell. When the battery module is in the charge / discharge stop state, the observed voltage of each battery cell reaches the average voltage of the entire battery cell, Further, control is performed so as to equalize the voltage by passing a current between the battery cells until reaching a voltage separated from the average voltage by a voltage fluctuation due to an internal resistance or polarization action of each battery cell. Battery voltage equalization control method.

Images