JP2008193871A - Battery management device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery management device for a vehicle that executes equalization of in-vehicle secondary batteries in an ignition switch on-state. <P>SOLUTION: In an ignition on-state of a vehicle mounted with a battery pack 1, charging/discharging currents of the battery pack 1 are forcibly reduced by a means, such as, a means that opens a main relay 4 that connects the battery pack 1 to a vehicular electrical system 7. Then, the need for equalization of each unit cell, constituting the battery pack 1, is determined. As a result of this, it is possible to surely confirm the need for equalization of each unit cell with the required accuracy, even when an ignition switch 12 has been turned on for a long time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle battery management device, and preferably to an improvement in a technique for equalizing assembled batteries formed by connecting a large number of lithium secondary batteries in series.

  An electric vehicle or a hybrid vehicle employs an assembled battery in which several hundred unit cells made of secondary batteries are connected in series for the purpose of reducing the wiring cross-sectional area and reducing the loss of switching elements. As the secondary battery, the use of a lithium secondary battery having excellent battery characteristics is being studied. However, the above-described lithium secondary battery has severe restrictions on overcharge and overdischarge. Therefore, in an assembled battery using a lithium secondary battery as a unit cell, an inter-cell voltage equalization circuit (hereinafter simply referred to as “equal”) that prevents overcharge and overdischarge of the unit cell by reducing voltage variation between unit cells. It is essential to provide a circuit. This type of equalization circuit is described, for example, in Patent Document 1 below. In addition, since the number of unit cells connected in series for a hybrid vehicle is very large, the unit cell group of the assembled battery is divided into a predetermined number of battery modules to reduce voltage variation between the battery modules. A circuit may be provided.

The operation of the equalization circuit (hereinafter also referred to as equalization operation or equalization) is performed by turning off the ignition switch in a secondary battery for a vehicle, particularly a secondary battery that is mounted on a hybrid vehicle and generates power for the vehicle. It was essential to do in the state. This is because, with the ignition switch turned on, due to charging / discharging between the electric system of the vehicle including the generator and electric load and the assembled battery, variations in polarization state and variations in internal resistance voltage drop between unit cells. This is because the cell voltage is changed and it is difficult to accurately detect the storage state based on the cell voltage.
Japanese Unexamined Patent Publication No. 2006-246646

  However, the equalization operation can only be performed when the ignition switch is turned off. The equalization operation cannot be performed in a vehicle that is always on, such as a taxi, or in a vehicle that travels for a long time. There was a problem in that the variation in capacity between them would increase. For this reason, there arises a problem that it is necessary to prevent the occurrence of overcharge and overdischarge of the unit cell by narrowing the allowable charge / discharge range of the battery.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle battery management device capable of equalizing a vehicle-mounted secondary battery in an ignition switch-on state.

  The vehicle battery management apparatus according to the first and second inventions that solve the above-described problems is an in-vehicle vehicle that is configured by connecting a large number of unit cells each made of a secondary battery in series and charging / discharging with an electric system of the vehicle. And an equalization control circuit for performing an equalization operation for equalizing the voltages of the unit cells based on the detected status report. This type of equalization control circuit is well known, for example, in lithium secondary batteries.

  The electric system of the vehicle mentioned above has at least power generation means and an electric load fed from the power generation means. Currently, an engine-driven generator is generally used as the power generation means, but other power generation means such as a fuel cell may be employed.

  In the first invention, in particular, it is determined whether or not the equalization control circuit can determine whether the equalization operation is necessary based on the driving state of the vehicle or the driving state of the assembled battery detected when the ignition switch is on. It is characterized in that the determination is performed when it is determined that the determination is possible, and then the equalization operation is performed when the determination result that equalization is necessary is obtained.

  That is, according to the present invention, each unit cell is maintained in a very stable state (hereinafter referred to as a stable state), and the state in which it is possible to determine whether or not equalization is necessary is the ignition switch on state of the vehicle. It was done with a focus on the fact that it sometimes appears. In addition, the stable state said here means the state where charging / discharging electric current is less than a predetermined threshold value, and it continued more than predetermined time. However, this predetermined time can be changed according to the charge / discharge state immediately before. For example, when the charge / discharge just before that is relatively quiet (small), the increase in the polarization state can be regarded as slight, so the predetermined time required for depolarization can be shortened. On the contrary, if the charge / discharge just before that is relatively intense (large), it can be considered that the increase in the polarization state may have increased, and therefore the above-mentioned predetermined time required for depolarization is sufficiently secured. There is a need to.

  For example, as the above-described stable state, an idling state (however, in the idling state immediately after starting the engine, a predetermined time should be subtracted from the start of idling), a long-term cruising state, and the like are conceivable. However, it is desirable to detect whether the charging / discharging current of the assembled battery has been below a predetermined threshold for a predetermined period.

  In this way, even when the ignition switch is on, the variation in the polarization state of each unit cell and the variation in the voltage drop due to the variation in the internal resistance value of each unit cell can be reduced. Therefore, it is possible to determine whether or not the equalizing operation is necessary with a necessary accuracy based on the voltage (cell voltage) of each unit cell.

  Furthermore, if this stable state continues, the equalization operation can be performed until the voltage variation of each unit cell becomes equal to or less than a predetermined value. If the charge / discharge current of the assembled battery greatly fluctuates during the determination of the necessity for the equalization operation, it is preferable to immediately stop it.

  In a preferred aspect, the equalization control circuit determines that the determination is possible when the idling state continues for a predetermined time or more. When the idling state is continued for a predetermined time or more, the battery converges to a stable state in both the hybrid vehicle and the normal engine vehicle, so that the necessity for the equalization operation can be easily determined. It should be noted that, for example, immediately after a large current is consumed, such as when the engine is started, it is preferable to subtract a predetermined time for recovering the current from the idling time.

  In a preferred aspect, the equalization control circuit detects information corresponding to the charging / discharging current of the assembled battery, and a state where the charging / discharging current of the assembled battery is less than a predetermined threshold is determined based on the information for a predetermined time. When the above is continued, it is determined that the determination is possible. In this way, since the battery converges to a stable state even in a state other than the idling state, for example, in a long-term cruising state, the necessity of the equalization operation can be easily determined.

  In particular, the equalization control circuit performs the determination after forcibly giving the unit cell a predetermined stable state necessary for determining whether the equalization operation is necessary in the ignition-on state. Thereafter, the equalization operation is performed when equalization is necessary based on the result of the determination.

  That is, in the present invention, even when the ignition switch is on and the assembled battery is being charged / discharged, it is determined whether equalization is required for each unit cell by forcibly suppressing charging / discharging of the assembled battery. Is possible. This suppression can immediately reduce the influence of the internal resistance voltage drop of each unit cell. In order to reduce the variation in the polarization state of each unit cell, it is preferable to perform the forced suppression of the charge / discharge for a predetermined time. For this reason, it is preferable to monitor the vehicle driving state and the charge / discharge state of the battery and perform the above-described suppression after a state in which the charge / discharge of the battery is not so strong continues for some time. Thereby, the time for performing the forced suppression for eliminating the polarization can be shortened.

  In the present invention, the above-mentioned forced suppression of charge / discharge is for determining whether or not the equalization operation is necessary, so that some polarization remains, which causes the voltage of each unit cell to vary due to polarization variation. Some variation is allowed. The equalization is preferably performed during a period when the assembled battery is not charged / discharged with respect to the electric system of the vehicle, but may be performed during a period when the assembled battery is charged / discharged with respect to the electric system of the vehicle. It doesn't matter.

  In a preferred aspect, the equalization control circuit releases the forced stable state given to the unit cell after determining whether the equalization operation is necessary. Thereby, since the time of the forced stable state given to an assembled battery can be made into the minimum, the fall of drivability etc. can be suppressed. When it is determined that the equalization operation is necessary as a result of the determination, the equalization operation can be performed with the ignition switch turned on.

  In a preferred aspect, the equalization control circuit determines an urgency level of the equalization operation based on a voltage difference between the unit cells when determining whether the equalization operation is necessary, and the urgency level is low. The equalization operation is delayed. In this way, since the equalization operation is delayed when the urgency of performing the equalization operation is relatively small, problems such as drivability during vehicle travel can be reduced. Note that the equalization operation delayed when the degree of urgency is low can be performed, for example, during an idling period, a highway cruising period, or an ignition off period that occurs thereafter.

  In a preferred aspect, the equalization control circuit maintains a state in which the electric power generation amount and the power consumption amount of the electric system of the vehicle are balanced so that the charge / discharge current of the assembled battery is equal to or less than a predetermined threshold value for a predetermined time. After continuing, the said determination is implemented. In this way, it is possible to suppress a decrease in determination accuracy due to polarization variation.

  In a preferred aspect, the equalization control circuit continues a state in which the switchgear that cuts off power transmission between the assembled battery and the electric system of the vehicle is opened for a predetermined time despite the ignition-on state, The determination is performed. In this way, it is possible to easily determine whether or not the equalization operation is necessary.

  In a preferred aspect, the forcing is delayed (prohibited) when it is determined that the forcing of the stable state to the unit cell is inappropriate based on the detected battery state or operating state. In this way, it is possible to prevent a decrease in drivability and amenity due to an insufficient amount of power exchanged with the electric system of the vehicle.

  In a preferred aspect, the equalization control circuit interrupts the equalization operation when it is determined that the equalization operation under the ignition switch on state is not preferable based on the detected battery state or operating state. Thereafter, the equalization operation is restarted after it is determined that the undesirable state has been resolved. In this way, the equalization operation is temporarily interrupted when the equalization operation is not preferable, such as when a battery charge / discharge amount that hinders the equalization discharge is necessary while the vehicle is running. , Drivability can be improved.

  In a preferred aspect, the determination as to whether or not the equalization operation is necessary is performed by detecting a voltage difference between the unit cells and performing unitization discharge among the unit cells based on the detected voltage difference. Including the operation of determining. As a result, prior to the equalization operation, unit cells to be subjected to equalization discharge are determined. Therefore, in the equalization discharge performed subsequently or later, only discharge of the corresponding unit cell can be performed. Operation can be simplified.

  In a preferred aspect, the equalization control circuit also determines a discharge time of a unit cell to be equalized and discharged based on the detected voltage difference when determining whether the equalization operation is necessary. For example, the discharge time extension is determined when the voltage difference is large, and the discharge time reduction is determined when the voltage difference is small. Thereby, the drivability fall by the equalization operation | movement during the subsequent ignition on period can be reduced.

(Modification)
In a preferred aspect, the power converter includes a power converter that exchanges power between an auxiliary battery mounted on the vehicle separately from the assembled battery and the electric system of the vehicle, and the equalization control circuit includes the electric system of the vehicle. The power converter is instructed to perform an operation for causing the auxiliary battery to absorb the unbalance between the power generation amount and the power consumption. In this way, since the auxiliary battery transmits and receives power to the electric system of the vehicle through a power conversion device such as a DCDC converter instead of the disconnected assembled battery, the power supply voltage fluctuation of the electric system of the vehicle is suppressed. can do. As the power conversion device, a type capable of bidirectional power transmission is adopted.

  A preferred embodiment of the above-described vehicle battery management apparatus of the present invention will be described below with reference to the drawings. It should be noted that the technical idea of the present invention should not be construed as being limited to the following embodiments, but may be implemented by combining other known techniques.

(Embodiment 1)
The vehicle battery management apparatus of Embodiment 1 is demonstrated with reference to FIG. FIG. 1 is a block circuit diagram showing a high voltage circuit of a hybrid vehicle.

  1 is an assembled battery, 2 is an auxiliary battery, 3 is a battery ECU (vehicle battery management device), 4 is a main relay, 5 is a DCDC converter, 6 is a boost converter, and 7 is a high-voltage generator that includes a generator motor of a hybrid vehicle. A vehicle electrical system 8 is a vehicle control ECU. Reference numeral 9 denotes three temperature sensors that detect the temperature of the assembled battery 1, and 10 denotes a current sensor that detects charging / discharging current of the assembled battery 1.

  The assembled battery 1 is configured by connecting a large number of unit cells composed of lithium secondary batteries in series. The auxiliary battery 2 is composed of a lead secondary battery and supplies power to a low voltage load. The battery ECU 3 includes an equalization device 11 therein. The battery ECU 3 reads the voltage of each unit cell of the assembled battery 1, the battery temperature detected by the temperature sensor 9, the charging / discharging current of the assembled battery 1 detected by the current sensor 10, and determines the battery state based on these information. . The determination result is transmitted to the vehicle control ECU 8, and the vehicle control ECU 8 controls operation states of an engine, a generator motor, and the like (not shown) based on the received battery state and the like. Reference numeral 12 denotes an ignition switch provided on a power supply line connecting the auxiliary battery 2 and the battery ECU 3, and the battery ECU 3 is activated when the ignition switch is turned on. The equalizing device 11 has a discharge circuit formed by connecting a resistor and a switch in series for each unit cell of the assembled battery 1 and discharges a necessary unit cell based on a command from the battery ECU 3.

  The assembled battery 1 is connected to the low voltage end of the boost converter 6 through the main relay 4, and the high voltage end of the boost converter 6 is connected to the vehicle electrical system 7 of the hybrid vehicle. The vehicle electrical system 7 includes an engine-driven generator, a generator motor that generates traveling power and generates power during braking, and a rotating electrical machine control device that controls them. When the electric power generated by the vehicular electric system 7 is larger than the consumed power, surplus electric power of the vehicular electric system 7 is transmitted to the assembled battery 1 through the boost converter 6 and the main relay 4. When the power consumption of the vehicular electrical system 7 is greater than the generated power, the stored power of the assembled battery 1 is transmitted to the vehicular electrical system 7 through the main relay 4 and the boost converter 6.

  The DCDC converter 5 is disposed between the boost converter 6 and the main relay 4, and feeds the electric power of the vehicle electric system 7 or the assembled battery 1 to the auxiliary battery 2. In this embodiment, the DCDC converter 5 is a unidirectional DCDC converter. However, if the DCDC converter 5 is a bidirectional DCDC converter, the auxiliary battery 2 is temporarily turned on when an ignition switch described later is turned on and the main relay 4 is opened (disconnected). Can be connected to the vehicle electrical system 7 instead of the assembled battery 1.

  When the ignition switch 12 is turned on, the battery ECU 3 and the vehicle control ECU 8 start, the vehicle control ECU 8 closes the main relay 4 through a predetermined procedure, operates the boost converter 6, and the assembled battery 1 supplies power to the vehicle control ECU 8. Combined so that it can be exchanged. When the ignition switch 12 is turned off, the vehicle control ECU 8 turns off the step-up converter 6 and the main relay 4 and then stops, and the battery ECU 3 also stops.

  The above-described configuration and basic operation of the high-voltage circuit system of the hybrid vehicle are essentially the same as those in the past, and thus further description thereof is omitted.

(Equalization necessity judgment routine)
The equalization necessity determination routine that characterizes this embodiment will be described with reference to the flowchart shown in FIG. This routine is periodically executed by interrupt processing.

  First, it is checked whether or not the ignition key is on (S100). If a predetermined time has elapsed after the ignition key is turned on, the process proceeds to step S102. Otherwise, this routine is terminated and the process returns to the main routine (not shown). To do.

  In step S102, the driving state of the vehicle and / or the driving state of the assembled battery 1 is detected. More specifically, in this embodiment, it is detected whether the idling state has continued for a predetermined time or whether the state where the charge / discharge current of the assembled battery 1 is less than a predetermined threshold has been continued for a predetermined time. In the next step S104, it is checked whether the equalization operation necessity can be determined based on the detected information. More specifically, when the idling state is continued for a predetermined time or when the state where the charging / discharging current of the assembled battery 1 is less than a predetermined threshold is continued for a predetermined time, the polarization of the assembled battery 1 is almost erased, And it can be estimated that the internal resistance voltage drop is small. Therefore, it is determined that the variation in voltage variation of the assembled battery 1 due to these factors is so small that it can be ignored, and it is determined that the necessity for equalization can be determined with high accuracy, and the process proceeds to step S106. This routine is terminated because it is difficult to determine the necessity of conversion, and the process returns to the main routine.

  In step S106 to step S110, the necessity of equalization of the assembled battery 1 is determined. More specifically, first, the voltage of each unit cell is detected (S106), and the voltage variation of each unit cell is calculated based on the lowest voltage among the detected voltages (S108). Thereafter, the cell number of the unit cell having a voltage variation exceeding a predetermined threshold voltage among the voltage variations of each unit cell and the voltage variation ΔV are written in the list (S110). Therefore, in this embodiment, it is determined that the equalization operation is necessary when a unit cell whose voltage variation exceeds the predetermined threshold voltage exists in the list.

(Equalization routine)
Next, the equalization routine will be described with reference to the flowchart shown in FIG. This routine is periodically executed by interrupt processing.

  First, it is checked whether or not the cell number of the unit cell and its voltage variation ΔV are written in the list (S120), and if written, an equalization operation is necessary, so the process proceeds to step S122. Since it is not necessary to perform the equalizing operation, this routine is terminated and the process returns to the main routine (not shown).

  In step S122, it is checked whether or not at least one of the written voltage variations ΔV exceeds a predetermined threshold value, and if it exceeds, it is determined that the urgent level of equalization is high and the equalization operation is started (S124). If not, it is checked whether or not the present time corresponds to a predetermined equalization preferable period (S126). Note that the equalization preferable period referred to here is, for example, an idling period after a predetermined time has elapsed from the start of idling in the idling period, or a state where the charge / discharge current of the assembled battery 1 is less than a predetermined threshold value for a predetermined time or more. The state that has passed shall be said. That is, this equalization suitable period means a period suitable for equalization operation, in which the polarization of the assembled battery 1 is sufficiently eliminated and the internal resistance voltage drop of the assembled battery 1 is sufficiently small. Note that it is not essential to perform the equalization operation during the equalization preferable period, and steps S122 and S126 may be omitted.

  In step S124, the unit cell written in the list is started to be equalized. The equalization operation itself is performed by operating the above-described discharge circuit connected in parallel to the corresponding unit cell, as in the prior art. At this time, the equalization apparatus 11 performs each unit cell that performs equalization discharge for a given discharge time. The discharge time of each unit cell is determined based on a map or formula stored in advance according to the voltage variation ΔV of each unit cell.

Next, the vehicle operation state and / or the operation state of the assembled battery 1 are read (S128), and it is determined based on the read information whether the current period is not preferable for continuing the equalization operation (S130). In this embodiment, the period unfavorable for the continuation of the equalizing operation refers to a period in which the charging / discharging current of the assembled battery 1 is larger than a predetermined value or the vehicle is greatly accelerated or decelerated. In this embodiment, the equalizing discharge in such a period is regarded as undesirable and is excluded.
Note that, depending on the equalization discharge circuit, the discharge amount is extremely fine as compared with the charge / discharge amount required in the vehicle control, and does not necessarily prevent the charge / discharge in the vehicle control. In this case, S128 and S130 may be omitted and the equalizing discharge may be continued.

  If it is determined that the current period is not preferable for the continuation of the equalization operation, the remaining discharge time obtained by subtracting the accumulated equalization discharge time from the discharge time of each unit cell to be equalized is listed for each unit cell. After the writing, the equalizing discharge is interrupted (S132). If it is determined that the present time is not an unfavorable period for continuing the equalization operation, the current remaining discharge time is calculated and written to the list for each unit cell in each equalization discharge, and the remaining discharge time is 0. The cell number of the unit cell which has become is deleted from the list (S134). Thereby, each unit cell which requires equalization discharge can be equalized.

  Further, in this embodiment, the equalization discharge is interrupted when a large charge / discharge or a sudden change in the running state occurs immediately before, so that the charge / discharge capacity of the assembled battery 1 of the hybrid vehicle is sufficiently high in such a state. It can be used for traveling.

(Embodiment 2)
The vehicle battery management apparatus of Embodiment 2 will be described with reference to FIG. FIG. 4 is a flowchart showing an equalization necessity determination routine. That is, this embodiment is a modification of the equalization necessity determination routine in the first embodiment.

(Equalization necessity judgment routine)
First, it is checked whether or not the ignition key is in an on state (S300). If a predetermined time has elapsed since the ignition key was turned on, the process proceeds to step S302. To do.

  In step S302, the driving state of the vehicle and / or the driving state of the assembled battery 1 is detected. Based on the detected information, whether or not large acceleration or deceleration of the vehicle has occurred in the immediately preceding predetermined period, and / or the immediately preceding predetermined period. It is then determined whether or not a state has occurred in which the charge / discharge current of the assembled battery 1 exceeds a predetermined large threshold value (S304). If it exists, it is preferable to avoid the determination of the necessity of equalization, so this routine is terminated and the process returns to the main routine.

  If there is no large acceleration or deceleration of the vehicle and / or large charge / discharge of the assembled battery 1 during the immediately preceding predetermined period, it is determined that the vehicle is in a relatively stable state suitable for determining the necessity of equalization. The forced stabilization operation to be described is performed (S306). The forced stabilization operation of this embodiment refers to an operation of opening the main relay 4. Thereby, the charging / discharging current of the assembled battery 1 is forced to be 0, and the internal resistance voltage drop is 0.

  Thereafter, it is checked whether or not a predetermined time that can substantially eliminate the polarization of the assembled battery 1 has passed (S308). If it has not passed, the process returns to step S302, and if it has passed, the necessity of equalization is determined (S310). Here, the determination of equalization necessity refers to step S106, step S108, and step S110 shown in FIG. Thereafter, the forced stabilization operation performed in step S308 is terminated, in other words, the main relay 4 is closed and the process returns to the main routine.

  In this way, it is possible to detect the voltage variation of the assembled battery 1, that is, the necessity for equalization, with high accuracy by eliminating the adverse effects of the polarization of the assembled battery 1 and the internal resistance voltage drop. Subsequent equalization processing may be performed by the routine of FIG.

  In this embodiment, since the assembled battery 1 is disconnected from the vehicle electrical system 7 during the forced stabilization operation, a generator connected to the engine of the vehicle electrical system 7 and a generator motor for generating travel power are provided. Will be directly connected, and there is a possibility of deterioration in driving controllability and fuel consumption. However, since this forced stabilization operation is performed for a short period for determining the necessity for equalization, such an adverse effect is relatively minor.

  Further, in this embodiment, if a large charge / discharge or a sudden change in the running state occurs immediately before, a forced stabilization operation is prohibited, so that an increase in polarization can be avoided and necessary for eliminating the polarization. Therefore, it is possible to further shorten the forced stabilization operation time.

  Furthermore, in this embodiment, when determining whether or not the equalization operation is necessary, the urgency level of the equalization operation is determined based on the voltage difference between the unit cells. If the urgency level is low, the equalization operation is further performed. In order to delay until a state suitable for performing the forced stabilization operation occurs, the forced stabilization operation may be performed in a state where the polarization of the assembled battery 1 is small and charging / discharging of the assembled battery 1 is not so required. The time required for the forced stabilization operation can be shortened accordingly.

(Modification)
In addition to the opening and closing of the main relay 4, the above-mentioned forced stabilization operation is performed in such a manner that the electric power generation amount of the vehicle electrical system 7 (that is, the engine-connected generator) A state in which the power generation amount) and the power consumption (almost power consumption of the generator motor for generating driving power) are balanced may be continued for a certain period of time. Even if it does in this way, the same effect as opening and closing of the main relay 4 can be acquired.

(Modification)
Each of the above-described embodiments is applied to a hybrid vehicle. However, for example, in a two-voltage power supply system for a vehicle that employs a lithium secondary battery as a high-voltage battery, it can also be applied to the high-voltage battery.

(Modification)
In addition, the auxiliary battery 2 may be excessively charged or excessively discharged during the period in which the main relay 4 is opened. In this way, it is possible to suppress the power imbalance of the vehicle electrical system 7 during the forced stabilization operation period.

(Modification)
If it is confirmed prior to the execution of the above equalization necessity determination routine whether or not the remaining capacity of the auxiliary battery 2 that supplies power to the battery ECU 3 is greater than a predetermined value, the equalization necessity determination routine is being executed. Thus, it is possible to prevent occurrence of poor execution of the equalization necessity determination routine.

1 is a block circuit diagram illustrating a circuit configuration of a vehicle battery management device according to Embodiment 1. FIG. 3 is a flowchart illustrating an equalization necessity determination routine according to the first embodiment. 3 is a flowchart illustrating an equalization routine according to the first embodiment. 10 is a flowchart illustrating an equalization necessity determination routine according to the second embodiment.

Explanation of symbols

1 assembled battery 2 auxiliary battery 3 battery ECU (equalization control circuit)
4 Main relay (switching device)
DESCRIPTION OF SYMBOLS 5 DCDC converter 6 Boost converter 7 Electric system for vehicles 9 Temperature sensor 10 Current sensor 11 Equalizer 12 Ignition switch

Claims (13)

A unit of a plurality of unit cells each consisting of a secondary battery is connected in series to detect the state of an in-vehicle assembled battery that charges and discharges with a vehicle electrical system, and the unit is based on the detected status report. In a vehicle battery management apparatus having an equalization control circuit that performs an equalization operation to equalize the voltage of a cell,
The equalization control circuit includes:
Check whether it is possible to determine whether the equalization operation is necessary based on the driving state of the vehicle or the driving state of the assembled battery detected in the ignition switch on state,
Performing the determination when it is determined that the determination is possible, and then
The vehicle battery management apparatus, wherein the equalization operation is performed when the result of the determination that equalization is necessary is obtained. In the vehicle battery management device according to claim 1,
The equalization control circuit includes:
A vehicle battery management apparatus that determines that the determination is possible when the idling state continues for a predetermined time or more. In the vehicle battery management device according to claim 1,
The equalization control circuit includes:
Information corresponding to the charging / discharging current of the assembled battery is detected, and it is determined that the determination is possible based on the information when the charging / discharging current of the assembled battery is less than a predetermined threshold for a predetermined time or more. A vehicle battery management device. A unit of a plurality of unit cells each consisting of a secondary battery is connected in series to detect the state of an in-vehicle assembled battery that charges and discharges with a vehicle electrical system, and the unit is based on the detected status report. In a vehicle battery management apparatus having an equalization control circuit that performs an equalization operation to equalize the voltage of a cell,
The equalization control circuit includes:
The determination is performed after forcibly giving a predetermined stable state necessary for determining whether the equalization operation is necessary to the unit cell in the ignition-on state, and then equalization is performed based on the determination result. A vehicle battery management apparatus that performs the equalization operation when necessary. The vehicle battery management device according to claim 4,
The equalization control circuit includes:
A vehicle battery management device for canceling a forced stable state given to the unit cell after determining whether the equalization operation is necessary. The vehicle battery management device according to claim 4,
The equalization control circuit includes:
When determining whether or not the equalization operation is necessary, a vehicle battery that determines an urgency level of the equalization operation based on a voltage difference between the unit cells and delays the equalization operation when the urgency level is low. Management device. The vehicle battery management device according to claim 4,
The equalization control circuit includes:
For a vehicle that performs the determination after continuing a state in which the amount of power generation and power consumption of the electric system of the vehicle is balanced for a certain time so that the charging / discharging current of the assembled battery is equal to or less than a predetermined threshold value Battery management device. The vehicle battery management device according to claim 4,
The equalization control circuit includes:
A vehicle battery management device that performs the determination after a switching device that cuts off power transmission between the assembled battery and the electric system of the vehicle is kept open for a certain period of time despite the ignition-on state. The vehicle battery management device according to claim 4,
The equalization control circuit includes:
A vehicle battery management device that releases the forcing when it is determined that the forcing of the stable state to the unit cell is inappropriate based on the detected battery state or driving state. In the vehicle battery management device according to claim 1 or 4,
The equalization control circuit includes:
When it is determined that the equalizing operation under the ignition switch on state is not preferable based on the detected battery state or operating state, the equalizing operation is interrupted, and then the undesirable state is resolved. A vehicle battery management apparatus that resumes the equalization operation after the determination. In the vehicle battery management device according to claim 1 or 4,
The determination of whether or not the equalization operation is necessary is performed by detecting a voltage difference between the unit cells and determining a unit cell to be equalized and discharged among the unit cells based on the detected voltage difference. Including vehicle battery management device. The vehicle battery management device according to claim 11,
The equalization control circuit includes:
A vehicle battery management apparatus for determining a discharge time of a unit cell to be equalized and discharged based on the detected voltage difference when determining whether or not the equalization operation is necessary. The vehicle battery management device according to any one of claims 1 to 12,
The assembled battery is a vehicle battery management device connected to a high-voltage electric system of a hybrid vehicle.

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