JP2015080345A - Charge-and-discharge controller of storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge-and-discharge controller of a storage battery which enables the reduction of occurrence of reaction unevenness accompanying the use in a plateau region.SOLUTION: A charge-and-discharge controller of a storage battery 6, in which a characteristic curve showing a voltage of the storage battery 6 to SOC(State of Charge) of the storage battery 6 and having a plateau region in a range of 40-60%, and a step region, comprises: an SOC forecasting part 2 operable to forecast a SOC of the storage battery 6; a setting part 3 operable to set a SOC control center which is a control target value of SOC of the storage battery in the step region; and a charge-and-discharge control part 5 operable to make a discharge request or charge request to the storage battery 6 based on the comparison with SOC forecast to be the SOC control center.

Description

  The present invention relates to a charge / discharge control device for a storage battery.

  Conventionally, techniques for controlling the amount of charge of a battery are known (see, for example, Patent Documents 1 to 5).

  For example, in the battery charging method described in Patent Document 1, at least one battery is charged at a first voltage for a first time period, and at least one battery is charged at a second voltage for a second time period. Further, the charging method determines the charging state of at least one battery at the end of the second time period, and if the at least one battery is not almost fully charged at the end of the second time period, the total charging time And determining whether or not at least one battery has been charged over a time period equal to or greater than the third time period. If the total charging time is less than the third time, the at least one battery is charged with the first voltage. Charging for one hour period and repeating the step of charging the battery with the second voltage for the second time period. Furthermore, this charging method is such that at least one battery is almost fully charged at the end of the second time period. The charging of at least one battery is stopped, or at the end of the second time period, if the total charging time is greater than or equal to the third time period, Even without to stop the charging of one battery.

JP-T-2005-513980 JP 2010-009983 A JP 2004-228010 A JP 2012-169093 A Japanese Patent Laid-Open No. 2003-047108

  However, when the battery is used in the plateau region, there is a problem that unevenness occurs in the reaction. In patent documents 1-5, generation | occurrence | production of such a reaction nonuniformity cannot be reduced. Due to the uneven reaction, there is a problem that the fuel consumption deteriorates and the output decreases.

  Therefore, this invention is providing the charging / discharging control apparatus of the storage battery which can reduce generation | occurrence | production of the reaction nonuniformity accompanying the use in a plateau area | region.

  The present invention is a charge / discharge control device for a storage battery, wherein a characteristic curve representing the voltage of the storage battery with respect to the SOC (State of Charge) of the storage battery has a plateau region and a step region in a range of 40% or more and 60% or less. . Based on the comparison between the SOC estimation unit that estimates the SOC of the storage battery, the setting unit that sets the SOC control center that is the control target value of the SOC of the storage battery, and the SOC that is estimated as the SOC control center, the discharge to the storage battery A charge / discharge requesting unit that makes a request or a charge request. The setting unit sets the SOC control center in the step region.

  According to the present invention, it is possible to reduce the occurrence of reaction unevenness accompanying use in the plateau region.

It is a schematic block diagram of the vehicle carrying the charging / discharging control apparatus of the storage battery according to embodiment of this invention. It is a figure showing an example with the charging / discharging curve showing OCV of the storage battery with respect to SOC of a storage battery. It is a figure showing another example of the charging / discharging curve showing OCV of the storage battery with respect to SOC of storage battery.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic configuration diagram of a vehicle 100 equipped with a storage battery charge / discharge control device according to an embodiment of the present invention.

  Referring to FIG. 1, vehicle 100 includes a storage battery 6, a PCU (Power Control Unit) 8, a motor generator (MG) 10, an ECU 1, a voltage measurement unit 12, a current measurement unit 14, A temperature measurement unit 16. The vehicle 100 is a hybrid vehicle that travels by at least one of the driving force of the motor generator 10 and the driving force of an engine (not shown). Instead of a hybrid vehicle, a fuel vehicle equipped with a fuel cell or an electric vehicle that runs only with the driving force of a motor generator may be used.

  The storage battery 6 is an assembled battery configured by connecting a plurality of battery modules in which a plurality of battery cells are integrated in series, and includes, for example, a lithium ion battery or a nickel metal hydride battery. And the storage battery 6 is comprised so that it may be charged / discharged via PCU8.

  The PCU 8 converts the DC power supplied from the storage battery 6 into AC power when the vehicle 100 is powered, and supplies the AC power to the motor generator 10. On the other hand, the PCU 8 converts AC power generated by the motor generator 10 into DC power during regenerative braking of the vehicle 100. The kinetic energy of the vehicle 100 is recovered as electric energy by converting to the battery 6 and supplying it to the storage battery 6. Further, the PCU 8 may include a step-up / down converter (DC / DC converter) that boosts the DC power supplied from the storage battery 6 or steps down the DC voltage supplied from the motor generator 10.

  The regenerative braking here refers to braking with power generation braking when the driver of the hybrid vehicle performs a foot braking operation, and power generation braking by turning off the accelerator pedal during traveling, although no foot brake operation is performed. Including decelerating (or stopping acceleration).

  Motor generator 10 is, for example, a three-phase AC rotating electric machine, receives AC power supplied from PCU 8, functions as an electric motor, and transmits driving force for running vehicle 100 to wheels (not shown). Further, the motor generator 10 functions as a generator by receiving the rotational driving force transmitted through the wheels, converts the kinetic energy of the vehicle 100 into electric power, and regenerates it to the storage battery 6 through the PCU 8.

  The ECU 1 performs arithmetic processing based on the driving state of the vehicle 100, the accelerator opening, the shift position, the SOC of the storage battery, and a map and program stored in a ROM (Read Only Memory) 3 built in the ECU 1. Thereby, ECU1 controls the equipment mounted in the vehicle so that it may be in the driving state according to a driver's operation directions.

  The ECU 1 includes a voltage measurement unit 12 that measures the charge / discharge voltage VBAT of the storage battery 6, a current measurement unit 14 that measures the input / output current IBAT of the storage battery 6, and a temperature measurement unit 16 that measures the battery temperature TBAT of the storage battery. It is connected. ECU 1 includes an SOC estimation unit 2, a setting unit 7, and a charge / discharge request unit 5.

  The SOC estimation unit 2 is based on the charge / discharge voltage VBAT of the storage battery 6, the input / output current IBAT of the storage battery 6, and the battery temperature TBAT of the storage battery 6 which are measured by the voltage measurement unit 12, the current measurement unit 14 and the temperature measurement unit 16, respectively. Then, the SOC of the storage battery 6 is estimated sequentially. The estimated SOC estimated value of the storage battery 6 is stored in a RAM (Random Access Memory) 4 built in the ECU 1.

  FIG. 2 is a diagram illustrating a charge / discharge curve representing an example of an open circuit voltage (hereinafter referred to as OCV) of the storage battery 6 with respect to the SOC of the storage battery 6.

  The charge / discharge curve in FIG. 2 has a step region S, a first plateau region P1, and a second plateau region P2 in a range where the SOC is 40% or more and 60% or less. In the present embodiment, the plateau region is a region where the change amount of OCV (ΔSOC / ΔOCV) with respect to the change amount of SOC is equal to or less than a first predetermined value (TH1). The step region is a region where the OCV change amount (ΔSOC / ΔOCV) exceeds the second predetermined value (TH2) with respect to the SOC change amount. However, TH2> TH1.

  In FIG. 2, the SOC of the first plateau region P1 is lower than the SOC of the step region S. The SOC of the second plateau region P2 is higher than the SOC of the step region S.

  The setting unit 7 sets the SOC value SA included in the step region S as the SOC control center, and sets the VA value corresponding to SA in the charge / discharge curve as the voltage control center.

  The setting unit 7 sets the SOC value SB included in the first plateau region P1 as the SOC lower limit value, and sets the voltage value VB corresponding to SB in the charge / discharge curve as the voltage lower limit value.

  The setting unit 7 sets the SOC value SC included in the second plateau region P2 to the SOC upper limit value, and sets the voltage value VC corresponding to SC in the charge / discharge curve to the voltage upper limit value.

  FIG. 3 is a diagram illustrating another example of a charge / discharge curve representing the OCV of storage battery 6 with respect to the SOC of storage battery 6.

  The charge / discharge curve in FIG. 3 has a plateau region P, a first step region S1, and a second step region S2 in a range where the SOC is 40% or more and 60% or less.

  In FIG. 3, the SOC of the first step region S <b> 1 is lower than the SOC of the plateau region P. The SOC of the second step region S2 is higher than the SOC of the plateau region P.

  The setting unit 7 sets the SOC value SD included in the plateau region P to the SOC control center, and sets the voltage value VD corresponding to SD in the charge / discharge curve to the voltage control center.

  The setting unit 7 sets the SOC value SE included in the first step region S1 to the SOC lower limit value, and sets the voltage value VE corresponding to SE in the charge / discharge curve to the voltage lower limit value.

  The setting unit 7 sets the SOC value SF included in the second step region S2 to the SOC upper limit value, and sets the voltage value VF corresponding to SF in the charge / discharge curve to the voltage upper limit value.

  Charging / discharging request unit 5 gives a control command to PCU 8 according to the estimated SOC value stored in RAM 4.

  The charge / discharge request unit 5 makes a discharge request to the storage battery 6 when the estimated SOC value is larger than the SOC control center. When the estimated SOC value is smaller than the SOC control center, the charge / discharge request unit 5 requests the storage battery 6 to be charged.

  The charge / discharge request unit 5 prohibits the discharge of the storage battery 6 when the estimated SOC value is equal to or lower than the SOC lower limit value. The charge / discharge request unit 5 prohibits charging of the storage battery 6 when the estimated SOC value is equal to or higher than the SOC upper limit value.

  In the present embodiment, the SOC control center, the SOC upper limit value, and the SOC lower limit value are set based on the step region and the plateau region in the charge / discharge curve representing the OCV with respect to the SOC. However, the present invention is not limited to this. . The SOC control center, the SOC upper limit value, and the SOC lower limit value may be set based on the step region and the plateau region in the charge / discharge curve representing VBAT with respect to the SOC.

  As described above, according to the present embodiment, when the charge / discharge curve has a plateau region and a step region in the range of 40% to 60%, the SOC control center is set in the step region. . By setting the SOC control center in which the usage time is long in the step region, it is possible to suppress the operation in the plateau region and prevent the reaction irregularity of the storage battery.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  2 SOC estimation unit, 5 charge / discharge request unit, 6 storage battery, 7 setting unit, 10 motor generator, 12 voltage measurement unit, 14 current measurement unit, 16 temperature measurement unit, TBAT battery temperature, VBAT charge / discharge voltage, OCV open voltage.

Claims (1)

A charge / discharge control device for a storage battery, wherein the characteristic curve representing the voltage of the storage battery relative to the SOC (State of Charge) of the storage battery has a step region and a plateau region in a range of 40% or more and 60% or less,
An estimation unit for estimating the SOC of the storage battery;
A setting unit for setting an SOC control center that is a control target value of the SOC of the power storage location;
A charge / discharge requesting unit that performs a discharge request or a charge request to the storage location based on a comparison between the SOC control center and the estimated SOC;
The said setting part is a charging / discharging control apparatus of a storage battery which sets the said SOC control center in the said step area | region.

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