JP2018057228A - Vehicle battery controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle battery controller capable of effectively extending a drivable distance of a vehicle to improve travel performance of the vehicle by performing efficient battery discharge control according to residual capacity of each battery when a plurality of batteries are connected in parallel.SOLUTION: When determination means 30 determines that total residual capacity E1r of a maximum charge amount battery group G1 is equal to or larger than prescribed capacity, a vehicle battery controller preferentially uses the maximum charge amount battery group G1. When it is determined that the total residual capacity E1r of the maximum charge amount battery group G1 is less than the prescribed capacity, the vehicle battery controller preferentially uses a battery group whose total residual capacity is less than the maximum charge amount battery group G1 and whose total residual capacity is larger than the prescribed capacity among a plurality of battery groups.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vehicle battery control device, and more particularly, to a vehicle battery control technique when an external power source charges a battery in an electric vehicle.

  In recent years, in PHEV vehicles (plug-in hybrid electric vehicles) and EV vehicles (electric vehicles), in order to extend the cruising range of the vehicle, it is necessary to mount a battery (battery) having a large chargeable electric capacity. It is growing. However, it is difficult to dramatically increase the energy density of the individual battery cells themselves constituting the battery.

  Therefore, in order to increase the capacity of the battery, a battery module in which a plurality of batteries are connected in parallel is formed. In Patent Document 1, when there is a voltage difference between two batteries connected in parallel, the battery on the lower voltage side, that is, the remaining capacity (hereinafter referred to as SOC (State of Charge)) which is the charging capacity of the battery is also referred to. A vehicle battery control device is disclosed in which only the battery on the side with a small amount of () is charged. Thereby, the voltage difference between two batteries is eliminated, and the contactor (electromagnetic contactor) connected to the electrode of each battery can be closed.

International Publication No. 2013/042165

  As described in Patent Document 1, when the number of batteries connected in parallel is two, in general, it is only necessary to preferentially use a battery with a large remaining capacity, and battery discharge control is relatively easy. It is. However, when three or more batteries are connected in parallel to extend the cruising distance of the vehicle, it is difficult to perform efficient battery discharge control according to the remaining capacity of each battery. If the balance of the remaining capacity of each battery becomes uneven, the contactor connected between the batteries cannot be closed and closed due to the voltage difference, so that the charging / discharging of each battery is restricted, and the running performance of the vehicle may be deteriorated. There is.

  The present invention has been made to solve at least some of these problems, and an object of the present invention is to provide an efficient battery according to the remaining capacity of each battery when a plurality of batteries are connected in parallel. An object of the present invention is to provide a vehicle battery control device that can effectively extend the cruising distance of a vehicle and improve the running performance of the vehicle by performing discharge control.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

(1) The vehicle battery control device according to this application example is a vehicle battery control device that discharges at least a plurality of batteries connected in parallel to each other, and the amount of electricity charged in each battery. Classifying means for detecting a certain remaining capacity and classifying each battery into a plurality of battery groups based on each remaining capacity, and the total remaining capacity of the battery group with the maximum charge amount classified as the battery having the largest remaining capacity by the classifying means. A battery group total remaining capacity calculating means for calculating; and a determining means for determining whether or not the total remaining capacity of the first battery group is equal to or greater than a predetermined minimum capacity necessary for running the vehicle, When it is determined that the total remaining capacity of the maximum charge amount battery group is equal to or greater than the predetermined capacity, the maximum charge amount battery group is preferentially used, and the total remaining capacity of the maximum charge amount battery group is determined to be less than the predetermined capacity. When, among the plurality of battery groups, the total remaining capacity is a battery group to be less than the maximum charge amount of the battery groups, a total remaining capacity is preferentially using battery group becomes larger than a predetermined capacity.

  According to the present invention using the application example, when a plurality of batteries are connected in parallel, efficient battery discharge control is performed according to the remaining capacity of each battery, thereby effectively extending the cruising distance of the vehicle. The driving performance of the vehicle can be improved.

It is a schematic block diagram of the electric vehicle provided with the battery control part which concerns on one Embodiment of this invention. It is the schematic diagram which showed the structure of the high voltage battery of FIG. It is a flowchart of the battery discharge control which ECU of FIG. 1 performs.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram of an electric vehicle including a vehicle battery control device according to an embodiment of the present invention, and will be described with reference to FIG.

  A vehicle 1 shown in FIG. 1 is an electric vehicle truck including a motor 2 as a travel drive source. The motor 2 is an electric motor that can also operate as a generator, such as a permanent magnet synchronous motor. The output shaft of the motor 2 is connected to a differential device 4 via a propeller shaft 3, and left and right drive wheels 6 are connected to the differential device 4 via a drive shaft 5.

  A high voltage battery (vehicle battery) 12 is connected to the motor 2 via an inverter / converter (hereinafter simply referred to as an inverter) 10 and a junction box 11. The DC power stored in the high voltage battery 12 is converted into AC power by the inverter 10 and supplied to the motor 2, and the driving force generated by the motor 2 is transmitted to the drive wheels 6 to cause the vehicle 1 to travel.

  For example, when the vehicle 1 decelerates or travels on a downhill road (regenerative travel), the motor 2 operates as a generator (regenerative operation) by reverse driving from the drive wheels 6 side. The negative driving force generated by the motor 2 is transmitted to the driving wheel 6 side as a braking force, and the AC power generated by the motor 2 is converted into DC power by the inverter 10, and a high voltage is supplied via the junction box 11. The battery 12 is charged.

  The high voltage battery 12 is, for example, a lithium ion battery, and is a traveling battery used for the motor 2 that is a drive source. The high voltage battery 12 has a predetermined operating temperature range appropriate for performance. The junction box 11 is connected to various electric devices mounted on the vehicle. Inside the junction box 11, various contactors (electromagnetic contactors) for connecting and disconnecting electric circuits are provided. By connecting and disconnecting the contactors, the supply and disconnection of electric power to various electric devices are controlled. Is possible.

  The junction box 11 is connected to a high voltage auxiliary machine 16 such as a cooler compressor and a pump of a power steering device. The high voltage auxiliary machines 16 operate by receiving power supply from the high voltage battery 12. Further, a low voltage battery 18 is also connected to the junction box 11 via a DC-DC converter 17.

  The DC-DC converter 17 is a voltage converter that steps down power supplied to the low voltage battery 18 via the junction box 11. The low voltage battery 18 is, for example, a lead battery, and the stored electric power has a lower voltage than the high voltage battery 12, but has a wider operating temperature range than the high voltage battery 12. The low voltage battery 18 is used, for example, for power supply to the ECU 30 and power supply such as a control power supply for a contactor.

  The junction box 11 can be connected to an external power source 20 and is connected to a charger 19 that can charge the high voltage battery 12 and the low voltage battery 18 from the external power source 20. The external power source 20 includes, for example, 100V and 200V ordinary charging for home use, quick charging, non-contact charging, and the like. Although one charger 19 is shown in the present embodiment, a plurality of chargers 19 may be provided corresponding to the external power source 20.

  Further, the vehicle 1 includes an input / output device (not shown), a storage device (ROM, RAM, etc.) used for storing control programs and control maps, a central processing unit (CPU), an ECU (determination unit) equipped with a timer counter, etc. Means) 30 is mounted. The ECU 30 in the present embodiment is a control unit that mainly controls the charging of the high-voltage battery 12, but the vehicle 1 may be provided with various other ECUs.

  Here, the ECU 30 is electrically connected to the high voltage battery 12, the charger 19, the vehicle speed sensor 31, and the like. The ECU 30 also includes an SOC detection / classification unit (classification unit) 32, a battery group total remaining capacity calculation unit (battery group total remaining capacity calculation unit) 33, and the like.

  FIG. 2 is a schematic diagram showing the configuration of the high voltage battery 12. The high voltage battery 12 is formed as a battery module in which, for example, six batteries B1 to B6 that are battery cells are connected in parallel to each other. The SOC detection / classification unit 32 detects the remaining capacity (SOC), which is the amount of electricity charged in each of the batteries B1 to B6, and classifies the batteries B1 to B6 into a plurality of battery groups based on the remaining capacity. . The battery group classification standard is such that the remaining capacities of the batteries B1 to B6 are relatively close to each other. Specifically, the battery group has a relatively small voltage difference within a range in which the contactor within the junction box 11 can be closed. For example, it is classified into the same battery group.

  In the case of FIG. 2, the charging states of the batteries B1 to B6 are SOC-H (%) in which the SOCs of the batteries B1 and B2 are the highest, and SOC-L (%) in which the SOC of the battery B6 is the lowest. The SOC of B3 to B5 is SOC-M (%) between SOC-L (%) and SOC-H (%). Therefore, each of the batteries B1 to B6 is classified by the SOC detection / classification unit 32 into one of the maximum charge amount battery group, the intermediate charge amount battery group, and the minimum charge amount battery group G1 to G3. The batteries B1 and B2 with the largest remaining capacity are classified into the maximum charge amount battery group G1, and the batteries B3, B4 and B5 with the next largest remaining capacity are classified into the intermediate charge amount battery group G2, and the minimum charge amount battery group The battery B6 having the smallest remaining capacity is classified as G3.

  Although not shown, when a battery corresponding to the intermediate charge amount battery group G2 includes a plurality of battery groups having different charge amounts, the first intermediate charge amount battery group G2 and the second intermediate charge are arranged in descending order of charge amount. Amount battery group G4, third intermediate charge amount battery group G5, and so on.

  The battery group total remaining capacity calculation unit 33 calculates total remaining capacity E1r to E3r of the maximum charge amount battery group, the intermediate charge amount battery group, and the minimum charge amount battery group G1 to G3, respectively. Based on these total remaining capacities E1r to E3r, powers P1 to P3 for driving the vehicle 1 can be output, respectively.

  Hereinafter, the battery discharge control according to the present embodiment will be described in detail with reference to the flowchart of FIG. 3. In the following description, it is assumed that the total remaining capacity E1r to E3r is larger in the order of E2r, E1r, and E3r, and the powers P1 to P3 are larger in the order of P2, P1, and P3. First, when traveling of the vehicle 1 is started via the vehicle speed sensor 31, the ECU 30 starts battery discharge control.

  In step S <b> 1, the ECU 30 determines whether or not the power P <b> 1 based on the total remaining capacity E <b> 1 r of the maximum charge amount battery group G <b> 1 acquired by the battery group total remaining capacity calculation unit 33 is equal to or greater than the minimum power Pmin that can travel the vehicle 1. The minimum power Pmin is based on a predetermined electric capacity (predetermined capacity) corresponding to the minimum amount of electricity that can travel while ensuring the performance of the vehicle 1 when the vehicle 1 is driven by the power of the high voltage battery 12. Determined.

  When the determination result is false (No), that is, when the power P1 that can be generated in the maximum charge amount battery group G1 is less than the minimum power Pmin, the process proceeds to step S2. On the other hand, when the determination result is true (Yes), that is, when the power P1 that can be generated in the maximum charge amount battery group G1 is equal to or greater than the minimum power Pmin, the process proceeds to step S3 and the maximum charge amount battery group G1. Select use and return to this control.

  In this case, it has been found that the vehicle 1 can be driven by the maximum charge amount battery group G1 in which the batteries B1 and B2 having the largest SOC among the battery groups G1 to G3 are classified. For this reason, by using a battery group with a high SOC, the balance of the remaining capacity of each battery group G1 to G3, and hence each battery B1 to B6 is made as uniform as possible, and contactors connected between the batteries B1 to B6 are arranged. In order to eliminate problems that cannot be closed due to a voltage difference as much as possible and improve the running performance of the vehicle 1, the batteries B1 and B2 having the largest remaining capacity are preferentially used from the group of maximum charge amount batteries G1 classified.

  In step S <b> 2, it is determined whether or not the power P <b> 2 based on the total remaining capacity E <b> 2 r of the intermediate charge amount battery group G <b> 2 acquired by the battery group total remaining capacity calculation unit 33 is equal to or greater than the minimum power Pmin that can travel the vehicle 1. When the determination result is true (Yes), that is, when the power P2 that can be generated in the intermediate charge amount battery group G2 is equal to or greater than the minimum power Pmin, the process proceeds to step S4 to use the intermediate charge amount battery group G2. Select and return to this control. On the other hand, when the determination result is false (No), that is, when the power P2 that can be generated in the intermediate charge amount battery group G2 is less than the minimum power Pmin, the process proceeds to step S3, and the maximum charge amount battery group G1. Select use and return to this control.

  Of the battery groups G1 to G3, in addition to the maximum charge amount battery group G1, the intermediate charge amount battery group G2 in which the batteries B3 to B5 having the remaining remaining capacity next to the maximum charge amount battery group G1 are also classified. In order to improve the running performance of the vehicle 1 by making the balance of the remaining capacities of the battery groups G1 to G3 and thus the batteries B1 to B6 as uniform as possible. The maximum charge amount battery group G1 in which the batteries B1 and B2 having the largest remaining capacity are classified is preferentially used.

  On the other hand, when the intermediate charge amount battery group G2 in which the batteries B3 to B5 having the second largest remaining capacity after the maximum charge amount battery group G1 are classified is found to be able to travel the vehicle 1. The intermediate charge amount battery group G2 in which the batteries B3 to B5 having the remaining remaining capacity next to the maximum charge amount battery group G1 are classified is used preferentially.

  As described above, in the present embodiment, when three or more, for example, six batteries B1 to B6 are connected in parallel to form the high voltage battery 12, each of the batteries B1 to B6 has a remaining capacity (SOC). By classifying the batteries B1 to B6 into the battery groups G1 to G3 and changing the order of using these battery groups G1 to G3, efficient battery discharge can be performed.

  Specifically, in the battery discharge control of the present embodiment, determination is made based on whether or not the minimum power Pmin of the vehicle 1 can be secured in steps S1 and S2. As a result, either the maximum charge amount battery group G1 in which the batteries B1 and B2 having the largest remaining capacity are classified or the intermediate charge amount battery group G2 in which the batteries B3 to B5 having the smallest remaining capacity are classified is discharged with priority. Therefore, it is possible to effectively extend the cruising distance of the vehicle 1 and improve the running performance of the vehicle 1.

  Further, in the intermediate charge amount battery group, there are a plurality of battery groups having different charge amounts, and the first intermediate charge amount battery group G2, the second intermediate charge amount battery group G4, and the third intermediate charge in descending order of the charge amount. Even in the case of classification such as the quantity battery group G5, the above-described logic can be extended and applied. That is, when the power P1 that can be generated by the maximum charge amount battery group G1 is equal to or greater than the minimum power Pmin, the maximum charge amount battery group G1 is preferentially used and the power that can be generated by the maximum charge amount battery group G1. When P1 is less than the minimum power Pmin and there is a battery group having a total remaining capacity that allows the vehicle 1 to travel among a plurality of intermediate battery groups, the battery group is preferentially used. .

  Although the description of the embodiment of the vehicle battery control device according to the present invention has been completed, the embodiment is not limited to the above embodiment.

  In the battery discharge control of the above embodiment, determination is made to preferentially discharge either the maximum charge amount battery group G1 or the intermediate charge amount battery group G2. However, the present invention is not limited to this, and control for preferentially discharging the minimum charge amount battery group G3 may be performed. Specifically, in step S1 of the battery discharge control, when the determination result is false (No), that is, when the power P1 that can be generated in the maximum charge amount battery group G1 is less than the minimum power Pmin, the maximum charge is performed. The battery other than the amount battery group G1 may be discharged, and the minimum charge amount battery group G3 may be discharged preferentially instead of the intermediate charge amount battery group G2. In this case, the minimum charge amount battery group G3 has a total remaining capacity E3r less than the total remaining capacity E1r of the maximum charge amount battery group G1, but the total remaining capacity E3r is larger than a predetermined capacity based on the minimum power Pmin. Is a condition.

  Further, the battery discharge control of the above embodiment is applicable when a plurality of (three or more) batteries are connected in parallel to form the high voltage battery 12, and the number of batteries constituting the high voltage battery 12 The number of classifications of the battery group is not limited to the above embodiment.

1 Vehicle 12 High Voltage Battery (Vehicle Battery)
30 ECU (determination means, control device)
32 SOC detection / classification unit (classification means)
33 battery group total remaining capacity calculation unit (battery group total remaining capacity calculation means)
B1 to B6 Battery G1 Maximum charge amount battery group (battery group)
G2 Intermediate charge battery group (battery group)
G3 Minimum charge battery group (battery group)

Claims (1)

A vehicle battery control device for discharging at least a plurality of batteries connected in parallel to each other,
Classification means for detecting a remaining capacity charged in each battery and classifying each battery into a plurality of battery groups based on each remaining capacity;
A battery group total remaining capacity calculating means for calculating a total remaining capacity of the maximum charge amount battery group maximum charge amount battery group classified as the battery having the largest remaining capacity by the classification means;
Determining means for determining whether or not a total remaining capacity of the first battery group is equal to or greater than a predetermined predetermined capacity necessary for running the vehicle;
When the determination means determines that the total remaining capacity of the maximum charge amount battery group is equal to or greater than the predetermined capacity, the maximum charge amount battery group is preferentially used, and the total remaining capacity of the maximum charge amount battery group is When it is determined that the capacity is less than the predetermined capacity, the battery group in which the total remaining capacity is less than the maximum charge amount battery group among the plurality of battery groups, and the total remaining capacity is larger than the predetermined capacity. A battery battery control device characterized by preferentially using a battery group.

Images