JP2009017733A - Battery charge-and-discharge controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently remove a memory effect of a battery by performing proper charge refreshing and discharge refreshing. <P>SOLUTION: The charge-and-discharge controller is constituted by a battery device 26, a power distributing portion 24 and a charge-and-discharge control portion 30 to perform charge-and-discharge operations. The battery device is divided into a plurality of blocks 27a, 27b, and charges and discharges independently for every 27a, 27b. The power distributing portion is connected with the battery device 26, and charges and discharges each battery block 27a, 27b changing arbitrarily current distribution. The charge-and-discharge control portion controls the power distributing portion 24 so that total output and input of the whole battery device 26 may become constant, charges the battery block at a charge side, and synchronizing with this, discharges the battery block at a discharge side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery charge / discharge control device, for example, a control system for controlling charge / discharge of a battery system mounted on a hybrid vehicle.

In recent years, hybrid vehicles driven by a vehicle drive motor in combination with a gasoline engine have attracted attention. Further, as the capacity and density of the battery mounted on the hybrid vehicle are rapidly increasing, the battery charge / discharge control technology has become important.
Charging / discharging of the battery mounted on this type of hybrid vehicle is controlled using a state of charge (SOC), which is a ratio of the remaining current amount to the full charge current amount, as an index. During traveling of the hybrid vehicle, charging and discharging are generally repeated in the range of SOC of 20 to 80%.

  FIG. 4 is a graph showing changes in battery charge / discharge in a hybrid vehicle. When the SOC is discharged to drive the motor during traveling and the SOC approaches 20%, the cycle is switched to charging, and the engine is charged by rotating the generator to the vicinity of 80%.

  By the way, in a hybrid vehicle, when the battery charge / discharge cycle is repeated, a memory effect is produced in the battery, as is well known. That is, as a result of repeated charge and discharge when the SOC is 20 to 80%, the original full charge state is not obtained. Therefore, in order to remove the memory effect, charging refresh for charging to SOC 100% and discharge refresh for discharging to SOC 0% are periodically performed.

Conventionally, various improvements have been proposed as a memory effect countermeasure. For example, in Patent Document 1, a battery effect system for a hybrid vehicle may be provided with a memory effect detecting means for detecting the occurrence of a battery effect, and a means for changing the level of the target charged amount when a memory effect is detected. Proposed.
JP 2003-47108 A

  In a hybrid vehicle, when charging refresh and discharge refresh are periodically performed on the battery, the fuel consumption differs between when running in the charge refresh mode and when running in the discharge refresh mode. Therefore, it may be misunderstood that an abnormality has occurred somewhere in the car.

  Further, there is a problem that the acceleration / deceleration feeling felt by the driver changes between when traveling in the discharge refresh mode and when traveling in the charge refresh mode. In order to prevent the acceleration / deceleration feeling from changing, it is necessary to finely adjust the motor output, the engine output, and the mechanical brake, and the adjustment becomes very complicated.

  Furthermore, depending on the type of hybrid vehicle, when the discharge refresh mode is set, the remaining battery level may be insufficient, and driving may not be possible.

  Therefore, an object of the present invention is to solve the problems of the prior art, perform appropriate charge refresh and discharge refresh, efficiently remove the memory effect of the battery, and perform when refresh is being performed. An object of the present invention is to provide a battery charge / discharge control device that maintains efficient charge / discharge performance without changing the acceleration / deceleration feeling while keeping the total input / output of the battery system constant.

  In order to achieve the above object, the present invention is divided into a plurality of blocks, a battery device capable of charging and discharging independently for each battery block, and connected to the battery device, and current distribution to each battery block. The power distribution unit for charging / discharging the battery unit arbitrarily and controlling the power distribution unit so that the total input / output of the entire battery device is constant, charging the battery block on the charging side, and synchronizing with this The battery block on the discharge side includes a charge / discharge control unit that performs a charge / discharge operation for discharging.

  According to the present invention, the battery device is divided into blocks, and appropriate charge refresh and discharge refresh are performed on each block, so that the memory effect of the battery can be efficiently removed and when the refresh is performed. When the battery system is not installed, the total input / output of the battery system is kept constant, and particularly when mounted on a hybrid vehicle, fuel efficiency and acceleration / deceleration feeling do not change, and efficient charge / discharge performance can be ensured.

Hereinafter, an embodiment of a battery charge / discharge control device according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a system configuration in which the battery charge / discharge control device of the present invention is applied to a battery control system of a hybrid vehicle.

  In FIG. 1, reference numeral 10 indicates an engine. The engine 10 is connected to a motor 14 and a generator 16 via a torque distributor 12, and the output of the engine 10 is distributed to the motor 14 and the generator 16. Drive wheels 20 are connected to the output shaft of the motor 14 via gears 18. On the other hand, the motor 14 and the generator 16 are connected to the power distribution unit 24 via the inverter 22. Reference numeral 26 indicates a battery device.

  In this embodiment, the battery device 26 is divided into two blocks, a first battery block 27a and a second battery block 27b. The 1st battery block 27a and the 2nd battery block 27b are comprised from the assembled battery which respectively connected many battery cells in series. In this embodiment, the first battery block 27a and the second battery block 27b are both connected in series with 100 battery cells having a capacity of 1.2 V and 7 Ah. The first battery block 27a and the second battery block 27b are connected in parallel to the power distribution unit 24, and the first battery block 27a and the second battery block 27b are charged and discharged independently of each other. It is possible to do.

  The power distribution unit 24 includes a circuit for arbitrarily changing the current distribution when charging and discharging the first battery block 27a and the second battery block 27b. Then, the charge / discharge control unit 30 controls the current distribution by the power distribution unit 24 so that the total input when the battery device 26 is viewed as a whole is constant based on the flowchart shown in FIG. For example, the first battery block 27a is charged, and the discharge-side battery block 27b is discharged in synchronization with the first battery block 27a. During this period, the total input / output of the battery device 26 is kept constant.

Therefore, the charge / discharge control according to the present embodiment will be described below with reference to the flowchart of FIG. 2 and the time chart showing the change in the charged amount in the battery device 26 shown in FIG.
In FIG. 2, steps S1 to S8 are alternated between the first battery block 27a and the second battery block 27b on the charging side and the other on the discharging side during normal operation of the hybrid vehicle. It is charge / discharge control for switching to. On the other hand, in steps S9 to S15, in order to remove the memory effect, one of the first battery block 27a and the second battery block 27b performs a discharge refresh that discharges to a storage amount% 0, The other is charge / discharge control that performs charge refresh in which the battery is fully charged in synchronism with this.

First, charge / discharge charge control that is normally performed during hybrid vehicle operation will be described.
First, when the engine of the vehicle is started, control is started, and in step S1, a discharge / discharge mode is set for the first battery block 27a and the second battery block 27b of the battery device 26. In step S2, for example, the first battery block 27a is discharged and the second battery block 27b is charged. In this case, in FIG. 1, the first battery block 27a energizes the inverter 22 via the power distribution unit 24, and the motor 14 is driven by the inverter 22 so that the output torque according to the operation state is obtained. . And since it is a hybrid vehicle, the output torque of the engine 10 is transmitted to the drive wheel 20 together with the output torque of the motor 14.

  On the other hand, the second battery block 27b in the charging mode is charged with electric power generated by the generator 16 driven by the engine 10. Therefore, as the operation time elapses, the amount of electricity stored in the first battery block 27a decreases, and on the contrary, the amount of electricity stored in the second battery block 27b increases.

  Next, in step S3, it is determined whether the total amount of charge / discharge input / output to / from the first battery block 27a and the second battery block 27b is a preset set value. If there is a deviation from the set value, the process proceeds to step S4, and the power distribution unit 24 adjusts the distribution of the current discharged by the first battery block 27a and the current charged by the second battery block. As a result of the current distribution adjustment, the total input / output is always kept constant for the battery device 26 as a whole.

  Thus, when the operation time of the hybrid vehicle has elapsed, the amount of electricity stored in the first battery block 27a decreases due to discharging, and the amount of electricity stored in the second battery block 27b increases due to charging. Therefore, in step S5, it is determined whether or not the charged amount of the first battery block in the discharge mode has decreased to a preset lower limit value (for example, 25% as shown in FIG. 3), and subsequent step S6. Then, it is determined whether or not the charged amount of the second battery block 27b in the charging mode has reached a preset upper limit value (for example, 75% as shown in FIG. 3).

As a result of the determination in step S5 and step S6, when the charged amount of the first battery block 27a decreases to the lower limit value and the charged amount of the second battery block 27b rises to the upper limit value, the process proceeds to step S7, where charge / discharge is performed. A command to switch modes is sent to the power distribution unit 24. Then, returning to step S2, the first battery block 27a that has been in the discharge mode so far is switched to charge, and the second battery block is switched to discharge.
Thereafter, the charge / discharge control in steps S2 to S7 is repeated. As shown in FIG. 3, the first battery block 27a and the second battery block 27b alternately charge and discharge, and the change in the amount of stored electricity is opposite to each other. The total input / output is kept constant.

  When the cumulative charge / discharge time increases in this way, there is a concern that a memory effect may occur due to repeated charge / discharge. Therefore, when a preset cumulative charge / discharge time has elapsed (yes in step S8), charge / discharge refresh in steps S9 to S15 is started.

  That is, if the first battery block 27a is a discharging battery block, the battery is discharged to 0%. And the 2nd battery block b will be charged to full charge synchronizing with this. During this time, it is determined whether or not the total amount of charge / discharge is a preset value (step S10). When there is a deviation from the set value, the process proceeds to step S11, and the power distribution unit 24 adjusts the distribution of the current discharged by the first battery block 27a and the current charged by the second battery block. As a result of the current distribution adjustment, the total input / output is always kept constant for the battery device 26 as a whole. Then, when it is detected that the charged amount of the first battery block 27a is 0% and the charged amount of the second battery block 27b is fully charged (steps S12 and S13), in step S14 A command to switch the circuit for discharging is sent to the power distribution unit 24, and this time, the first battery block 27a performs charge refresh and the second battery block 27b performs discharge refresh. In this way, when the charge / discharge refresh is alternately repeated twice (step S15), the process returns to step S2 to perform normal charge / discharge control.

  As described above, since the charge / discharge refresh for removing the memory effect is automatically performed at a constant cycle, the discharge characteristics of the first battery block 27a and the second battery block 27 are changed by the memory effect, thereby improving the efficiency. Can be prevented in advance. Moreover, since the total input / output of the battery device 26 as a whole is kept constant during the refresh, the fuel consumption changes compared to the normal charge / discharge, and the acceleration / deceleration fee that the driver feels is also experienced. The ring never changes.

The block diagram which shows the system configuration | structure of the battery charging / discharging control apparatus by one Embodiment of this invention. The flowchart which shows the flow of a process of battery charging / discharging control. The figure which shows the time change of charging / discharging of the battery system by the battery charging / discharging control of this invention. The figure which shows the time change of charging / discharging of the battery system by battery charging / discharging control of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 12 Torque distributor 14 Motor 16 Generator 18 Gear 20 Drive wheel 22 Inverter 24 Power distribution part 26 Battery device 27a 1st battery block 27b 2nd battery block 30 Charge / discharge control apparatus

Claims (4)

A battery device divided into a plurality of blocks and capable of charging and discharging independently for each battery block;
A power distribution unit connected to the battery device and charging / discharging each battery block by arbitrarily changing the current distribution;
Charge / discharge operation for controlling the power distribution unit so that the total input / output of the entire battery device is constant, charging the battery block on the charging side, and discharging the battery block on the discharging side in synchronization with the charging A charge / discharge control unit for carrying out
A battery charge / discharge control apparatus comprising:   The battery charge / discharge control apparatus according to claim 1, wherein the charge / discharge control unit alternately switches charge / discharge modes of the battery block on the charge side and the battery block on the discharge side under a predetermined condition.   The charge / discharge control unit performs a discharge refresh that discharges the battery block on the discharge side to a storage amount of 0 in a constant cycle, and performs a charge refresh that charges the battery block on the charge side to a full charge synchronously. The battery charge / discharge control device according to claim 1, wherein the battery charge / discharge control device is implemented.   4. The battery charge / discharge control device according to claim 1, wherein the battery device is a battery system of a vehicle driving motor mounted on a hybrid vehicle. 5.

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