JP2011019329A - Secondary battery device and vehicle - Google Patents

Abstract

It is an object of the present invention to avoid a state in which voltage detection accuracy is not lowered and energy equalization is not insufficient because there is no time during operation of a management function.
In the present invention, a plurality of modules or a plurality of modules each having a plurality of cells formed into blocks, an execution block 100 for equalizing energy variation, and a management block 200 for providing control information are controlled, In the execution block, an energy state detection signal including information corresponding to each voltage information and each temperature of each cell is generated, and in the management block, cell designation information and control for controlling variation based on the energy state detection signal The execution block determines the energy equalization process of the cell when the management block is stopped using the cell designation information and the control time information sent.
[Selection] Figure 1

Description

  The present invention relates to a secondary battery device and a vehicle.

  In general, in an assembled battery pack that uses secondary batteries (cells) combined in series, the internal state of the combined secondary batteries becomes non-uniform due to charge / discharge of the secondary batteries and temperature variations. It is known to come. When the energy stored in the secondary battery becomes uneven, it becomes impossible to perform efficient charge and discharge so that the function as the battery pack can be utilized to the maximum. A resistance discharge system (Patent Document 1, Patent Document 2, Patent Document 3) is known as a circuit for performing such energy equalization.

Japanese Patent Laid-Open No. 11-150877, “Voltage Correction Circuit for Secondary Battery” Registration No. 3312001 “Battery voltage correction device for battery pack” JP 2007-244142 “Battery Group Control Device and Battery Power Supply System”

  Patent Document 1: In this voltage correction circuit for a secondary battery, a variation in battery voltage or capacity is determined, and a high energy battery is connected to a resistor and discharged. However, in spite of the combined use of the voltage detection circuit and the balance circuit, it is not considered that the detection value of the battery voltage fluctuates due to the operation of the balance circuit, and the voltage is accurately detected. I can't say that.

  Patent Document 2: This battery voltage correction device for an assembled battery performs a discharge process for level adjustment before charging. The battery pack has a discharge end timing and discharges toward that voltage. Since the battery energy needs to be emptied, it can only be used in a limited way.

  Patent Document 3: In this battery group control device and battery power supply system, the energy between each unit cell is measured with no-load voltage, the remaining capacity between each unit cell is calculated, and the average remaining capacity between unit cells is calculated. A method for bypassing charge / discharge current has been proposed for a cell having a deviation of a set value or more. The calculation of the remaining capacity is already known, but the balance control operates only when the charging / discharging current is flowing, so a long balance time is required. Then, when the management function is operating, time is insufficient, and balance control becomes insufficient.

  In the present invention, it is high when the battery management function is stopped for the purpose of preventing voltage detection accuracy from being lowered and avoiding a situation where there is no time and energy equalization is not insufficient during operation of the management function. An object of the present invention is to provide a secondary battery device capable of equalizing energy between cells by discharging energy cells. Another object of the present invention is to provide a vehicle equipped with the secondary battery device. It is another object of the present invention to provide an apparatus for performing a good energy equalization process when a main switch of a vehicle equipped with the secondary battery is turned off and the battery management function is stopped.

  In order to solve the above problems, the present invention estimates the remaining energy capacity of each unit cell while the battery management function is operating, and determines the remaining energy capacity of the minimum unit cell and the remaining energy between the unit cells. Calculate the difference in energy capacity. A discharge time corresponding to the difference in the remaining energy capacity is calculated, and information on the discharge operation cell and the discharge time is transmitted to the energy equalizing unit in advance. Next, when the battery management function is stopped, the equalization unit has a function for recognizing that the battery management function is stopped. When the battery management function is stopped, the energy equalization unit performs control for energy equalization. carry out.

  In the present invention, during the energy equalization operation, the battery management function is stopped, the voltage detection accuracy is not lowered, and there is no time during the operation of the management function so that the energy equalization of the cell is not insufficient. Can be avoided.

It is a configuration explanatory view according to an embodiment of the present invention. It is structure explanatory drawing which concerns on the other Example of this invention. It is structure explanatory drawing which concerns on the further another Example of this invention. It is composition explanatory drawing concerning the further another Example of this invention. It is structure explanatory drawing which concerns on the further another Example of this invention. It is operation | movement explanatory drawing shown in order to demonstrate operation | movement of the apparatus of FIG. It is a figure which shows an example of the use condition of the apparatus of this invention.

  The first embodiment will be described below with reference to FIG. The secondary battery pack includes an assembled battery unit in which x unit cells are connected in series, a secondary battery state detection unit 30 that detects the state of the secondary battery, and an energy equalization unit 31 that equalizes the energy of each cell. Reciprocal communication between the secondary battery management unit 40 for managing the state of the secondary battery, the energy variation detection / operation cell determination unit 41, the secondary battery state detection unit 30 and the secondary battery management unit 40. Basically, a bidirectional communication unit 50 is provided.

  Here, from the functional classification, the block including the secondary battery state detection unit 30 and the energy equalization unit 31 that equalizes the energy of each cell is referred to as an execution block 100, and the state of the secondary battery is managed. A block including the secondary battery management unit 40 and the energy variation detection / operation cell determination unit 41 will be referred to as a management block 200. The execution block 100 and the management block 200 are similarly classified in other embodiments.

  A positive electrode terminal 21 and a negative electrode terminal 22 are provided at both ends of the x cells 11-1 to 11-x.

  Both ends of each cell are connected to an energy equalization unit 31. The energy equalization unit 31 charges and discharges each cell, and equalizes the energy of each cell based on energy equalization information described later. can do. The energy equalization unit 31 includes a charge / discharge switch for short-circuiting between the positive and negative electrodes of each cell via a charge / discharge resistor. For example, one end of a resistor 31-rx and a resistor 31-r (x-1) is connected to the plus terminal and the minus terminal of the cell 11-x, and these resistor 31-rx and resistor 31-r (x- The other terminal of 1) can be short-circuited or opened by the charge / discharge switch 31-sx. Similar charge / discharge switches are associated with other cells. The switch includes a semiconductor element such as an FET (Field Effect Transistor).

  In the configuration in which the resistance is provided on the positive electrode and negative electrode sides of the cell as described above, the connection line can be used as a cell voltage detection line. Resistance discharge can be performed by closing the charge / discharge switch for a high-energy cell. The resistor can have the effect of preventing a short circuit of the voltage detection line and the effect of cell equalization discharge use. This discharge time is set according to an energy difference described later, and may require a relatively long time (for example, about 2 hours).

  The energy equalization unit 31 includes an equalization control unit 31-1 for storing control information for performing equalization. Based on the equalization control information stored in the equalization control unit 31-1, the charge / discharge switch is controlled and equalization is performed. The equalization control information is sent from the secondary battery management unit 40 described later.

  Said secondary battery state detection part 30 can detect the energy state of a cell. As a result, a cell energy state detection signal is generated. The energy state detection signal includes voltage information of all cells and information corresponding to the temperatures of all cells or information corresponding to the temperature of a module in which two or more cells are grouped into ten or less. When acquiring each voltage information of a cell, the connection line of the both terminals of each cell is connected to the energy state detection control unit 30-1 via a detection switch.

  Further, the detection of the energy state is performed by controlling the detection switch based on the control information stored in the energy state detection control unit 30-1. The energy state detection control unit 30-1 may be a microprocessor integrated with the previous equalization control unit 31-1.

  The cell energy state detection signal is sent to the energy variation detection / operation cell determination unit 41 in the secondary battery management unit 40 via the bidirectional communication unit 50. The energy variation detection / operation cell determination unit 41 detects an energy variation for each cell of the secondary battery based on the energy state detection signal, and determines an operation cell for controlling the variation. For this purpose, for example, the energy remaining capacity of all the cells is estimated using the cell voltage information of all the cells as the energy state detection signal and the cell temperature information corresponding to the temperatures of all the cells. The information corresponding to the cell temperature means the temperature information of all cells or the temperature information of a module in which a plurality of unit cells are collected.

  Next, based on the energy remaining capacity of all the cells, a cell determined to be equalized, that is, an operation cell whose variation is to be controlled is determined. In determining the operation cell, a cell having a difference equal to or larger than a predetermined threshold with respect to the minimum remaining energy is selected.

  Then, the secondary battery management unit 40 generates equalization control information for equalizing the variation. In addition, a shutdown signal described later can be generated. The equalization control information includes operation cell designation information that identifies cells to be adjusted for equalization, and equalization control time information. The equalization control time information is calculated from the difference between the energy remaining capacity and the minimum energy remaining capacity of the specified cell. This equalization control information corresponds to the discharge time of the corresponding cell described above.

  The shutdown signal indicates that the operation of the secondary battery management unit 40 has been stopped, and is transmitted to the energy equalization unit 31. The shutdown signal may not be a special signal, and for example, the fact that the clock of I2C communication used in the secondary battery management unit 40 is stopped may be determined as the output of the shutdown signal. Further, in the case of a secondary battery device mounted on a vehicle, a signal generated when the main key of the vehicle is turned off may be used.

  According to the above-described apparatus, equalization control is performed when the secondary battery management unit 40 is stopped. Therefore, when the time during which the secondary battery management unit 40 is stopped is long, equalization is effectively performed even if the control time for equalization is long. The equalization control may require a very long time. For example, a time of 2 to 3 hours to several tens of hours may be required. This is because the current required for equalization cannot be increased due to the influence of heat generation or the like. In addition, there are many cells.

  Therefore, the energy consumed by the secondary battery management unit 40 during the time when the equalization control is performed can be suppressed during the equalization control. In addition, the operation of the secondary battery management unit 40 does not affect the operation of the equalization control, and the equalization control with high accuracy can be performed. In other words, when the secondary battery management unit 40 operates even when equalization control is being performed, the power consumption progresses at the same time, so the secondary battery state detection accuracy deteriorates. There is nothing.

  FIG. 2 shows another embodiment of the present invention. The present invention is not limited to the configuration described above, and a plurality of series connected cell rows may be connected in parallel. In other words, a column of x cells 21-1 to 21-x is connected in parallel to a column of x cells 11-1 to 11-x. The secondary battery state detection unit 30 and the energy equalization unit 31 correspond to the columns of the cells 11-1 to 11-x, and the secondary battery state detection unit 30B corresponds to the columns of the cells 12-1 to 12-x. And the energy equalization part 31B respond | corresponds. The secondary battery state detection units 30 and 30B and the energy equalization units 31 and 31B are connected to the secondary battery management unit 40 via the bidirectional communication unit 50. The control units 30-1 and 31-1 are also provided in the secondary battery state detection unit 30B and the energy equalization unit 31B, respectively. Also in this embodiment, the cell equalization process is performed when the secondary battery management unit 40 is stopped. As described above, a plurality of execution blocks 100 are connected in parallel, and each execution block executes a cell energy equalization process. In addition, the same code | symbol is attached | subjected to the component corresponding to a previous Example, and description is abbreviate | omitted.

  FIG. 3 shows still another embodiment of the present invention. In the case of this embodiment, for example, 2 to 10 cells are used as one module. In this embodiment, N cells from the cell 11-1 to the cell 11- (N) are handled as one module. In this example, three modules M1, M2, and M3 are illustrated. Each module includes a plurality of cells, a secondary battery state detection unit, and an energy equalization unit. And each secondary battery state detection part 30a, 30b, 30c and energy equalization part 31a, 31b, 31c are provided with control part 30-1, 31-1, respectively.

  Here, between the modules M1 and M2 and between the modules M2 and M3, inter-module bidirectional communication units 50a and 50b are provided. The bidirectional communication unit 50 is a final communication unit, and is provided between the secondary battery management unit 40 and the module M1 at the end.

  The energy state detection signal of the cell of the module M3 is transmitted to the secondary battery management unit 40 via the bidirectional communication units 50b, 50a, 50, and the energy state detection signal of the cell of the module M2 is transmitted to the bidirectional communication unit 50a, 50, the energy state detection signal of the cell of the module M1 is transmitted to the secondary battery management unit 40 via the bidirectional communication unit 50. The equalization control information for the module M3 is transmitted from the secondary battery management unit 40 via the bidirectional communication units 50, 50a, and 50b, and the equalization control information for the module M2 is transmitted from the secondary battery management unit 40 to both sides. The equalization control information for the module M1 is transmitted from the secondary battery management unit 40 via the bidirectional communication unit 50. The equalization process in each module is executed in the same manner as in the previous embodiment. That is, when the shutdown signal is received, the equalization process starts when the clock stops.

  In this embodiment, in a battery pack with a large number of series / parallel, it is possible to increase the simultaneity of the timing of state detection by providing a detection function for each module individually and by providing a communication function. The accuracy of control can be improved. Although not specifically described, the address information of each cell indicating which cell is located where is managed as table data by the control units 31-1, 30-1 and the secondary battery management unit 40. Yes. Cell address management is the same in other embodiments. For example, the operation cell designation information includes a cell address.

  FIG. 4 shows still another embodiment of the present invention. In the case of this embodiment, the type of information transmitted by the bidirectional communication unit 50 is clarified. That is, the types of detection information output from the secondary voltage detection unit 30 to the secondary battery management unit 40 include cell voltage information 61 of all unit cells, temperature information of all unit cells, or unit cells. Cell temperature information 62 of modules in which 2 to 10 are collected. As types of control information output from the secondary battery management unit 40 to the secondary voltage detection unit 30, there are operating cell designation information 52 and equalization control time information 53.

  The secondary battery management unit 40 uses the voltage information 61 of all unit cells transmitted from the secondary battery detection unit 30 and the information 62 corresponding to the temperature of the unit cells, and the remaining energy of all unit cells. Is estimated. The information corresponding to the temperature of the unit cell means the temperature information of all the unit cells or the temperature information of the module in which the unit cells are collected.

  Based on the remaining energy of all unit cells, a cell to be equalized, that is, an operation designated cell is determined. The operation designated cell is a cell having a difference of a predetermined threshold value or more with respect to the minimum remaining energy. For the energy difference with respect to the minimum remaining energy, for example, the equalization control time of the operation designated cell is calculated based on the resistance value of the equalization unit and the time during which the equalization switch can be turned on. For example, the resistance value of the unit cell 11-1 in FIG.

  The time during which the equalization switch can be turned on is the voltage detection line and the circuit that doubles as the equalization circuit. If the equalization switch is turned on while the voltage is being detected, the voltage detection accuracy will be reduced. It means time other than voltage detection time.

  By transmitting the cell designation information and the control time information to the equalization unit, the equalization unit 31 performs equalization control based on the transmitted cell designation information and control time information even when the management unit 40 is stopped. Can be implemented. Performing equalization control without driving the management unit 40 is effective in suppressing energy consumed by the management unit.

  FIG. 5 shows still another embodiment of the present invention. In this embodiment, the inside of the energy variation detection / operation cell determination unit 41 in the secondary battery management unit 40 is shown in detail. Here, a current detection unit 80 that flows in, for example, the whole cell connected in series (may be for each unit) is provided, and this detection information is transmitted to the energy variation detection / operation cell determination unit 41 via the communication unit 70. Sent.

  The energy variation detection / operation cell determination unit 41 includes a current determination unit 211, each unit cell remaining energy capacity estimation unit 212, a database 213, and an operation cell determination and control time calculation unit 214.

  In this apparatus, the degree of variation in energy between unit cells of the secondary battery pack is detected, and an operation cell for equalizing the variation between unit cells is determined.

  The no-current state is determined by the no-current determination unit 211. The database 213 is a database having a correlation between the cell voltage, temperature, and remaining energy capacity. Using this database, each unit cell remaining energy capacity estimation unit 212 estimates the remaining energy capacity of the unit cell from the cell voltage and the cell temperature or the temperature of the module in which two or more unit cells are grouped.

  Next, the operation cell determination and control time calculation unit 214 calculates the deviation of the remaining energy capacity of each unit cell with respect to the cell of the minimum remaining energy capacity in the secondary battery pack, and the deviation of the capacity is determined in advance. Those exceeding the set value are determined as operation cells, and the equalization control time is calculated from the residual energy capacity deviation of the operation cells.

  FIG. 6 is a flowchart showing the above operation. The current determination unit 211 determines whether there is no current using the current data of the battery pack (step SA0). When it is determined that there is no current state, the remaining energy capacity of each unit cell is estimated from each unit cell voltage and temperature using the database 213 having a correlation between the cell voltage, temperature and remaining energy capacity in the no current state. (Step SA1-SA6). The minimum remaining energy capacity is calculated from the remaining energy capacity of each unit cell, and a cell having a difference between the remaining energy capacity of each unit cell and the minimum remaining energy capacity of ΔSOC or more is determined as an operating cell (steps SA7 to SA12). .

  By using the database, the remaining energy capacity of each unit cell can be calculated from the unit cell and temperature. The equalization unit can perform equalization control based on the transmitted operation cell designation information and control time information.

  As described above, the present invention does not decrease the voltage detection accuracy, and can avoid a state where there is no time during the operation of the management function and cell energy equalization is not insufficient.

  Various settings can be made for the timing for generating the energy state detection signal and the timing for obtaining the operation cell designation information and the control time information. For example, the operation timing setting data for the execution block 100 and the management block 200 may be input or adjusted from the outside in accordance with the usage mode of the electric vehicle apparatus to which the present invention is applied. Alternatively, the operation timing application may be stored in the ROM so that the ROM can be exchanged. The execution block 100 operates while the management block 200 is stopped, but it is also assumed that the management block 200 is activated during the equalization process. In such a case, the equalization process may be interrupted and the equalization process may be continuously performed on the remaining cells at the next timing (when the management block 200 is stopped), or newly You may perform based on the acquired operation | movement cell designation | designated information and control time information.

  FIG. 7 shows a system example when the secondary battery device of the present invention is mounted on an electric vehicle or a hybrid vehicle. Reference numeral 1000 denotes an automobile chassis. An execution block 100 and a management block 200 according to the present invention are mounted on the battery management board 300. A plurality of cells or a plurality of modules are incorporated in the assembled battery pack 400. The positive and negative electrodes of the battery pack 400 are connected to a voltage conversion and operation control unit 500 that includes an inverter and converts a voltage and receives an operation command and performs level control and phase control of output current and voltage. . The output of the voltage conversion and operation control unit 500 is supplied to the motor 600 as drive power. The rotation of the motor 600 is transmitted to the drive wheels WR and WL via, for example, a differential gear unit.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Various embodiments may be combined and implemented, or a part of the embodiments may be omitted as long as they are within the scope of the present invention.

11-1 to 11-x ... cell, 21,22 ... electrode terminal, 30 ... secondary battery state detection unit, 31 ... energy equalization unit, 31-s1-31-sx Switch, 31-r1-31-rx ... resistor, 40 ... secondary battery management unit, 41 ... energy variation detection / operation cell determination unit, 50 ... bidirectional communication unit.

Claims (6)

A plurality of cells connected in series, or a plurality of modules each having a plurality of cells formed into blocks; an execution block for equalizing energy variation among the plurality of cells; and a management block for providing control information to the execution blocks. And
The execution block stores cell designation information and control time information sent from the management block. When the management block is stopped, a switch group is set based on the cell designation information and control time information. A secondary battery device that controls and executes an energy equalization process of a cell. The management block is
Based on the energy state detection signal, the energy variation between the cells is detected, a cell to be short-circuited to control the variation is determined, and the determination unit obtains the cell designation information and the control time information,
The execution block is
A group of switches that are individually provided in the plurality of cells and switch between both terminals of the same cell to an open state and a short circuit state via a charge / discharge resistor,
A secondary battery device comprising: a battery state detection unit that generates an energy state detection signal including information on each voltage of each cell or each module and information corresponding to each temperature. 3. The secondary battery device according to claim 2, wherein the execution block detects either a shutdown signal of the management block or a stop of a communication clock signal, and the management block stops operating. The charge / discharge resistance is:
Between the first resistor installed between the positive electrode of each unit cell battery and one end of the corresponding switch, and the other end of the switch corresponding to the negative electrode of each unit cell battery The secondary battery device according to claim 2, further comprising a second resistor installed. Furthermore, a current detection unit for detecting a current in the system path of the plurality of cells is provided,
The determination unit for obtaining the operation cell designation information and the control time information is
A database that correlates cell voltage, temperature, and remaining energy capacity in a no-current state;
Estimating a remaining current capacity of a unit cell by determining a no-current state detected by the current detection unit and using the database to estimate a remaining energy capacity of a unit cell from a cell voltage and a cell temperature or a temperature of a plurality of modules having the plurality of cells blocked And
Calculate the deviation of the remaining energy capacity of each unit cell with respect to the cell with the minimum remaining energy capacity, determine that the deviation of the capacity exceeds a preset value, and determine the remaining energy capacity of the operating cell. The secondary battery device according to claim 2, further comprising an operation cell determination and control time calculation unit that calculates a balance control time from the deviation.   A vehicle equipped with any one of the secondary battery devices according to claim 1.

Images