JP2009017752A - Battery control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery control device in which a battery can be effectively used while maintaining a battery service life up to the use period as a target. <P>SOLUTION: In a battery ECU 13, the target amount of deterioration is calculated which represents a deteriorated state according to the use period of the battery 2 in order that the battery 2 reaches the end of its service life at the target use period, and the whole amount of deterioration is calculated which represents the deterioration state at current time of the battery 2, while in an engine ECU 14, a charge/discharge part 3 is controlled so that the whole amount of deterioration approaches the target amount of deterioration and so that charge and discharge to/from the battery 2 is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery control device that controls a charging / discharging unit that charges and discharges a rechargeable battery.

Conventional battery control devices include an operator between a power mode that controls battery charging / discharging with emphasis on motor driving performance and a long life mode that controls charging / discharging of the battery in consideration of reducing the burden on the battery. By setting the battery output upper limit and the regeneration upper limit based on the control mode selected by the operation and the battery charge rate, and controlling the charge and discharge of the battery so as not to exceed the set output upper limit and the regeneration upper limit Some have made it possible to control charge and discharge in consideration of the deterioration rate of the battery (for example, see Patent Document 1).
JP 2003-199211 A

  However, the above-described conventional technology has a problem that the battery life is shorter than the target usage period due to the operation of the operator, or the battery is not used effectively due to excessive consideration of reducing the burden on the battery. there were.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a battery control device that can effectively use a battery while maintaining the life of the battery until a target use period. To do.

  The battery control device according to the present invention is a battery control device that controls a charge / discharge unit that charges and discharges a rechargeable battery according to a use period of the battery so that the battery has a life in a target use period. A target deterioration amount calculation unit that calculates a target deterioration amount that represents a deterioration state; an overall deterioration amount calculation unit that calculates an overall deterioration amount that represents a current deterioration state of the battery; and the overall deterioration amount approaches the target deterioration amount Thus, it has the structure provided with the control part which controls the said charging / discharging part.

  With this configuration, the battery control device according to the present invention controls the charging / discharging unit so that the overall deterioration amount of the battery approaches the target deterioration amount that represents a deterioration state that is allowed according to the battery usage period. The battery can be used effectively while maintaining the life of the battery until the usage period.

  The overall deterioration amount calculation unit is based on the charging rate when the battery starts discharging, the depth of discharge from when the battery starts discharging, and the temperature when calculating the charging rate at the start of discharging the battery. The total deterioration amount may be calculated by calculating the deterioration amount at the time of discharging the battery and integrating the calculated deterioration amounts.

  In addition, the overall deterioration amount calculation unit multiplies the charging value by the integrated discharge amount obtained by integrating the current value when the battery is discharged from the completion of the recovery charge and the current value when the battery is charged. The charge rate of the battery may be calculated by calculating the sum of the obtained value and the accumulated charge amount accumulated from the completion of the recovery charge and dividing the sum by the battery capacity.

  The total deterioration amount calculation unit may calculate the total deterioration amount based on the direct current internal resistance value when the direct current internal resistance value of the battery is higher than a preset value. Good.

  Further, the control unit may control the charge / discharge unit to suppress discharge from the battery when a value obtained by subtracting the total deterioration amount from the target deterioration amount is equal to or less than zero.

  In addition, when the value obtained by subtracting the total deterioration amount from the target deterioration amount is greater than 0, the control unit calculates a dischargeable amount for the battery based on the value, the temperature of the battery, and a charging rate. Then, the charge / discharge unit may be controlled so that the calculated dischargeable amount is discharged from the battery.

  The battery control device of the present invention may include a nonvolatile storage medium, and the control unit may appropriately store at least one of the target deterioration amount or the overall deterioration amount in the storage medium.

  The present invention can provide a battery control device having an effect that the battery can be used effectively while maintaining the life of the battery until the target usage period.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, an example in which the battery control device according to the present invention is applied to a battery mounted on a vehicle will be described.

  FIG. 1 shows a battery control device according to an embodiment of the present invention.

  As shown in FIG. 1, the battery control device 1 includes a current sensor 10 that detects a charge / discharge current value of a rechargeable battery 2, a voltage sensor 11 that detects a voltage value between both electrodes of the battery 2, A temperature sensor 12 for detecting temperature, a battery ECU (Electronic Control Unit) 13 for detecting the state of the battery 2, an engine ECU 14 for controlling the charging / discharging unit 3 for charging and discharging the battery 2, a button, a touch panel, An input device 15 configured by a remote controller or the like and a display device 16 configured by a liquid crystal display, an LED (Light Emitting Diode), or the like are provided.

  In the present embodiment, the battery 2 is composed of a liquid lead-acid battery, and the charging / discharging unit 3 is composed of a load on the battery 2 such as an engine or an accessory and an alternator that generates electric power with the driving force of the engine. It shall be.

  The battery 2 is provided so as to be charged when the power consumption of the load is lower than the generated power of the alternator and to be discharged when the power consumption of the load is higher than the generated power of the alternator.

  The battery ECU 13 includes a processor such as a CPU (Central Processing Unit) and a memory, and constitutes a target deterioration amount calculation unit and an overall deterioration amount calculation unit in the present invention. Moreover, battery ECU13 comprises the control part in this invention with engine ECU14.

  The battery ECU 13 calculates a value representing the state of the battery 2 based on detection results of the current sensor 10, the voltage sensor 11, and the temperature sensor 12. Specifically, the battery ECU 13 uses, as a value representing the state of the battery 2, an accumulated discharge amount and an accumulated charge amount after completion of the recovery charge of the battery 2, a current charging efficiency and a charging rate (State Of Charge, hereinafter simply referred to as “state of charge”). "SOC"), the amount of deterioration at the time of discharge, the total amount of deterioration indicating the current deterioration state, and the target indicating the deterioration state according to the usage period of the battery 2 for the battery 2 to reach the end of its life in the target usage period The amount of deterioration is calculated.

  The battery ECU 13 calculates the SOC at predetermined time intervals (for example, 10 ms intervals) during charging and discharging. Here, the battery ECU 13 calculates the integrated discharge amount by integrating the current value detected by the current sensor 10 when the battery 2 is discharged from the completion of the recovery charge, and when the battery 2 is charging. By multiplying the value obtained by multiplying the current efficiency by the charging efficiency from the completion of recovery charging, the integrated charge amount is calculated, the sum of the integrated discharge amount and the integrated charge amount is calculated, and divided by the battery capacity, The SOC is calculated.

  Regarding the charging efficiency, the battery ECU 13 refers to the charging efficiency table as shown in FIG. 2 stored in the internal memory, and based on the SOC calculated immediately before and the temperature detected by the temperature sensor 12. It comes to calculate.

  Further, the battery ECU 13 calculates a depth of discharge (hereinafter simply referred to as “DOD”) from the difference between the SOC when the battery 2 starts discharging and the SOC when the battery 2 ends discharging. Then, referring to the discharge deterioration amount table as shown in FIG. 3 stored in the internal memory, based on the DOD, the SOC when the battery 2 starts to discharge, and the temperature detected by the temperature sensor 12. The amount of deterioration during discharge is calculated.

  On the other hand, when the battery 2 is in a state where neither the battery 2 is charged nor discharged (hereinafter, simply referred to as “abandoned state”), the battery ECU 13 performs SOC at a predetermined time interval (for example, one hour interval). 4 is referred to, and the amount of deterioration due to the leaving state is calculated based on the SOC and the temperature detected by the temperature sensor 12 with reference to a table of amount of leaving state deterioration as shown in FIG.

  Further, the battery ECU 13 calculates the total deterioration amount by integrating the deterioration amount from the start of use of the battery 2.

  Further, the battery ECU 13 has a timer, measures the usage period of the battery 2 using the timer, and indicates a deterioration state corresponding to the usage period of the battery 2 for the battery 2 to reach the end of its life in the target usage period. The amount of deterioration is calculated. The target usage period may be, for example, 3 years, or may be a period set via the input device 15 or the like.

  Based on each value representing the state of the battery 2 calculated in this way, the battery ECU 13 notifies the charge / discharge unit 3 to control the engine ECU 14 to charge and discharge the battery 2. .

  Specifically, when the total deterioration amount reaches 100%, the battery ECU 13 notifies the engine ECU 14 to prohibit the charging / discharging unit 3 from discharging the battery 2.

  Further, when the SOC becomes a predetermined value (for example, 85%) or less, the battery ECU 13 causes the charging / discharging unit 3 to suppress the discharging of the battery 2 and notifies the engine ECU 14 to charge. Yes. Further, when the accumulated discharge amount exceeds a predetermined value, the battery ECU 13 notifies the engine ECU 14 to cause the charging / discharging unit 3 to perform recovery charging.

  Further, when the value obtained by subtracting the total deterioration amount from the target deterioration amount (hereinafter simply referred to as “allowable deterioration amount”) is not 0 or more, the battery ECU 13 causes the charging / discharging unit 3 to suppress discharge of the battery 2. The engine ECU 14 is notified.

  On the other hand, when the allowable deterioration amount is 0 or more, the battery ECU 13 refers to the discharge deterioration amount table shown in FIG. 3, and based on the allowable deterioration amount, the temperature detected by the temperature sensor 12, and the SOC. Then, the DOD that allows the battery 2 to discharge (hereinafter simply referred to as “allowable DOD”) is calculated, and the charge / discharge unit 3 is notified to the engine ECU 14 to allow the discharge of the battery 2 by the allowable DOD. Yes.

  The engine ECU 14 has a processor such as a CPU and a memory, and controls the engine speed, the amount of power generated by the alternator, and the like. For example, the engine ECU 14 sets the alternator in a low power generation state when the vehicle is accelerated, reduces the load on the engine, and sets the alternator in a high power generation state when the vehicle is decelerated to raise the SOC of the battery 2. Yes.

  In particular, the engine ECU 14 permits the charging / discharging unit 3 to discharge the battery 2 within the range of the discharge amount allowed by the battery ECU 13. For example, the engine ECU 14 performs idling stop until the load consumes the discharge amount permitted by the battery ECU 13, or reduces the load on the alternator by reducing the alternator load by reducing the alternator load or generating power. The engine which comprises the charging / discharging part 3 is controlled so that it may consume.

  The operation of the battery control device 1 configured as described above will be described with reference to FIGS.

  First, in FIG. 5, whether or not the total deterioration amount of the battery 2 is 100% is determined by the battery ECU 13 (S1), and if it is determined that the total deterioration amount of the battery 2 is 100%, The battery ECU 13 notifies the engine ECU 14 that the discharging unit 3 prohibits the discharging of the battery 2, and the engine ECU 14 controls the charging / discharging unit 3 so that the battery 2 is not discharged (S2).

  Further, whether or not recovery charging is requested is determined by the battery ECU 13 (S3). If it is determined that recovery charging is required, the engine ECU 14 indicates that the charging / discharging unit 3 performs recovery charging. The charging and discharging unit 3 controlled by the engine ECU 14 starts recovery charging of the battery 2 (S4). When recovery charge is requested, the recovery charge request flag stored in the memory of the battery ECU 13 is set to the on state.

  When the battery ECU 13 detects that the battery 2 is in a charged state (S5), the operation of the battery control device 1 moves to the charging operation shown in FIG. 6 (S6).

  In the charging operation shown in FIG. 6, the SOC is calculated by the battery ECU 13 at a predetermined time interval (for example, every 10 ms) (S20).

  Here, at the time of recovery charging (S21), when the recovery charging is completed, that is, when the SOC reaches 100% and a state where a predetermined amount of electricity is charged is detected by the battery ECU 13 (S22), the charging / discharging unit 3 is notified to the engine ECU 14 that the recovery charging is terminated, and the recovery charging of the battery 2 is terminated by the charging / discharging unit 3 controlled by the engine ECU 14 (S23).

  Here, the recovery charge request flag is set to the OFF state by the battery ECU 13 (S24), the SOC calculated by the battery ECU 13 is reset to 100%, and the integrated discharge amount is reset to a predetermined initial value (S25). When the battery ECU 13 detects that the battery 2 is no longer charged (S26), the operation of the battery control device 1 returns to the original operation shown in FIG.

  In FIG. 5, when the battery ECU 13 detects that the battery 2 has been discharged (S7), the operation of the battery control device 1 proceeds to the discharge determination operation shown in FIG. 7 (S8).

  In the discharge determination operation shown in FIG. 7, the target deterioration amount is calculated by the battery ECU 13 (S30). Next, an allowable deterioration amount obtained by subtracting the overall deterioration amount from the target deterioration amount is calculated (S31), and the battery ECU 13 determines whether or not the allowable deterioration amount is greater than 0 (S32).

  If it is determined that the allowable deterioration amount is not greater than 0, the battery ECU 13 notifies the engine ECU 14 to stop discharging the battery 2 (S33), and the operation of the battery control device 1 is as shown in FIG. Return to the original operation shown in. On the other hand, when it is determined that the allowable deterioration amount is greater than 0, the operation of the battery control device 1 proceeds to the discharging operation shown in FIG. 8 (S34).

  In the discharging operation shown in FIG. 8, first, the SOC is calculated by the battery ECU 13 and recorded in the memory inside the battery ECU 13 (S40). Next, based on the allowable deterioration amount, the temperature of the battery 2, and the calculated SOC, the allowable DOD is calculated by the battery ECU 13 (S41).

  Here, the SOC is calculated by the battery ECU 13 at a predetermined time interval (for example, 10 ms) (S42), and the DOD (hereinafter, “current DOD”) is calculated from the difference between the SOC recorded in the memory and the SOC calculated at the present time. Is calculated by the battery ECU 13 (S43).

  Next, whether or not the current DOD is less than the allowable DOD is determined by the battery ECU 13 (S44). If it is determined that the current DOD is not less than the allowable DOD, the battery ECU 13 stops discharging the battery 2 to the engine ECU 14. Is notified (S45).

  Next, it is determined by the battery ECU 13 whether or not the accumulated discharge amount is larger than a predetermined value (S46). If it is determined that the accumulated discharge amount is larger than the predetermined value, the recovery charge request flag is turned on by the battery ECU 13. (S47).

  Here, when the battery ECU 13 detects that the battery 2 is in a discharged state (S48), the operation of the battery control device 1 returns to step S42. On the other hand, when it is detected by the battery ECU 13 that the battery 2 is no longer discharged, the deterioration amount is calculated based on the current DOD, the SOC recorded in the memory, and the temperature of the battery 2 (S49). The calculated deterioration amount is added to the total deterioration amount (S50).

  In FIG. 5, when the battery ECU 13 detects that the battery 2 is in the neglected state (S9), the operation of the battery control device 1 moves to the neglected operation shown in FIG. 9 (S10).

  In the leaving operation shown in FIG. 9, the SOC is calculated by the battery ECU 13 at a predetermined time interval (for example, one hour interval) (S60), and the deterioration amount due to the leaving state is calculated based on the calculated SOC and the temperature of the battery 2. Is calculated (S61).

  The calculated deterioration amount is added to the total deterioration amount by the battery ECU 13 (S62). If the battery ECU 13 detects that the battery 2 is no longer left (S63), the operation of the battery control device 1 returns to the original operation shown in FIG.

  As shown in FIG. 10, the battery control apparatus 1 according to the embodiment of the present invention has an overall deterioration amount of the battery 2 in a target deterioration amount that represents a deterioration state that is allowed according to the usage period of the battery 2. Since the charging / discharging unit 3 is controlled so as to approach, the battery 2 can be used effectively while maintaining the life of the battery 2 until the target usage period.

  In the present embodiment, the example in which the battery ECU 13 calculates the total deterioration amount by integrating the deterioration amount when the battery 2 is discharged and the deterioration amount due to the leaving state has been described. However, the battery 2 has deteriorated. As the battery 2 progresses and the direct current internal resistance value (hereinafter simply referred to as “DCIR”) of the battery 2 increases to some extent, the accuracy of the overall deterioration amount calculated from the DCIR of the battery 2 increases.

  For this reason, the battery ECU 13 simultaneously outputs the voltage value detected by the voltage sensor 11 and the current value detected by the current sensor 10 a plurality of times in a short time (when the discharge of a large current such as engine start occurs) When the DCIR value of the battery 2 derived from the correlation between the voltage and current obtained by acquiring (for example, at least twice in 10 ms) becomes higher than a preset value, it is stored in the internal memory. The total deterioration amount may be calculated based on DCIR and SOC with reference to the total deterioration amount table as shown in FIG.

  Further, the battery ECU 13 calculates the overall deterioration amount using an internal resistance value obtained by another internal resistance value measurement method (for example, a measurement method using an alternating current of the battery internal resistance value) instead of the DC internal resistance value. It is good.

  Further, the battery ECU 13 may cause the display device 16 to display the calculated allowable DOD, SOC and deterioration amount, the state of the recovery charge request flag, the period until the battery 2 reaches the end of its life, and the like.

  Further, in preparation for when the power supply to the battery ECU 13 is interrupted, the battery control device 1 includes a non-volatile storage medium such as a hard disk or a flash memory, and the battery ECU 13 provides at least the target deterioration amount and the total deterioration amount to the non-volatile storage medium. May be stored periodically or in accordance with each value.

  Moreover, although the battery 2 of one embodiment of the present invention is a liquid lead acid battery, the present invention is not limited thereto, and for example, a lithium ion battery, a nickel hydride battery, a nickel cadmium battery, etc. should be used similarly. Can do.

  As described above, the battery control device according to the present invention has an effect that the battery can be used effectively while maintaining the life of the battery until the target usage period. It is useful as a battery control device or the like that controls a charge / discharge unit that performs charging and discharging.

The block diagram of the battery control apparatus in one embodiment of this invention Charging efficiency table referred to by battery control device in one embodiment of the present invention Discharge deterioration amount table referred to by battery control device in one embodiment of the present invention Abandoned state deterioration amount table referred to by the battery control device in one embodiment of the present invention The flowchart for demonstrating operation | movement of the battery control apparatus in one embodiment of this invention. The flowchart for demonstrating the charging operation of the battery control apparatus in one embodiment of this invention The flowchart for demonstrating discharge judgment operation | movement of the battery control apparatus in one embodiment of this invention The flowchart for demonstrating the discharge operation of the battery control apparatus in one embodiment of this invention The flowchart for demonstrating the leaving operation of the battery control apparatus in one embodiment of this invention The graph for demonstrating the effect | action of the battery control apparatus in one embodiment of this invention Total deterioration amount table referred to by battery control apparatus in one embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery control apparatus 2 Battery 3 Charging / discharging part 10 Current sensor 11 Voltage sensor 12 Temperature sensor 13 Battery ECU
14 Engine ECU
15 Input device 16 Display device

Claims (7)

In a battery control device that controls a charge / discharge unit that charges and discharges a rechargeable battery,
A target deterioration amount calculation unit that calculates a target deterioration amount that represents a deterioration state according to the use period of the battery for the battery to have a lifetime in the target use period;
An overall deterioration amount calculation unit for calculating an overall deterioration amount representing a current deterioration state of the battery;
A battery control device comprising: a control unit that controls the charge / discharge unit so that the overall deterioration amount approaches the target deterioration amount.   The overall deterioration amount calculation unit is based on the charging rate when the battery starts discharging, the depth of discharge from when the battery starts discharging, and the temperature when calculating the charging rate at the start of discharging the battery. The battery control device according to claim 1, wherein the overall deterioration amount is calculated by calculating a deterioration amount when the battery is discharged and integrating the calculated deterioration amounts.   The total deterioration amount calculation unit is a value obtained by multiplying a current value when the battery is discharged from the accumulated discharge amount accumulated from the completion of the recovery charge and a current value when the battery is charged multiplied by the charging efficiency. 3. The battery control according to claim 2, wherein the charge rate of the battery is calculated by calculating a sum of the accumulated charge amount accumulated from the completion of the recovery charge and dividing by a capacity of the battery. apparatus.   The total deterioration amount calculating unit calculates the total deterioration amount based on the internal resistance value when the internal resistance value of the battery becomes higher than a preset value. The battery control device described in 1.   The said control part controls a charging / discharging part so that the discharge from the said battery may be suppressed, when the value which subtracted the said whole deterioration amount from the said target deterioration amount is 0 or less. The battery control device according to claim 4.   When the value obtained by subtracting the total deterioration amount from the target deterioration amount is greater than 0, the control unit calculates a dischargeable amount for the battery based on the value, the temperature of the battery, and a charging rate. 6. The battery control device according to claim 1, wherein the charge / discharge unit is controlled such that the calculated dischargeable amount is discharged from the battery. The battery control device includes a nonvolatile storage medium,
The battery control device according to any one of claims 1 to 6, wherein the control unit appropriately stores at least one of the target deterioration amount or the overall deterioration amount in the storage medium.

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