JP4188271B2 - Vehicle battery management device - Google Patents

Description

  The present invention relates to a vehicle battery management apparatus that monitors a charge / discharge state of a battery in a hybrid vehicle, an electric vehicle, or the like equipped with both an engine and an electric motor, and manages the battery easily and appropriately.

  In recent years, in vehicles such as automobiles, various types of hybrid vehicles using both an engine and a motor and electric vehicles that can run only by a motor have been developed and put into practical use from the viewpoint of low pollution and resource saving.

Such hybrid vehicles and electric vehicles generally have an energy regeneration function of generating power using deceleration energy during deceleration and charging the battery. For example, in Japanese Patent Application Laid-Open No. 2001-103602, a vehicle that is set in advance when the accelerator pedal and the brake pedal are not depressed and the deceleration at the time of vehicle deceleration is smaller than a predetermined value. A technique is disclosed in which the regenerative torque obtained from the driving state map is generated by an electric motor and added to the engine brake torque. Then, the state of charge of the battery is checked, and if the remaining capacity of the battery is lower than a predetermined value, the motor generator functions as a generator to charge the battery, while if the remaining capacity of the battery is higher than the predetermined value, Since the function of the generator as a generator leads to overcharging of the battery, control for reducing the vehicle speed by fuel cut is described.
JP 2001-103602 A

  However, when trying to manage the battery with the remaining capacity of the battery as described in Patent Document 1 described above, complicated calculation processing using a plurality of parameters is required, and detection errors and calculation errors for each of these parameters are required. On the other hand, accurate battery management becomes difficult, and battery charge control may not be performed accurately.

  Further, in such a hybrid vehicle, when frequent regeneration is possible, even if the amount of charge other than during regeneration is reduced, the battery balance is sufficient. Also, by appropriately managing such a battery balance, it is possible to expect a large improvement in fuel efficiency of about several percent to several tens of percent compared to the case where normal charging is always performed.

  The present invention has been made in view of the above circumstances, and can easily and accurately manage the battery. Also, by appropriately managing the battery balance in consideration of regeneration, the fuel efficiency can be greatly improved. An object of the present invention is to provide a battery management device for a vehicle that can achieve the above.

The present invention provides a battery management device for a vehicle that activates an inverter device connected to a generator based on a voltage value to be set and executes constant voltage charging for the battery, and is preset according to the driving state of the vehicle. and determining whether or not regeneration condition determining means have regenerating condition is met, the regeneration execution means for executing a regeneration process by setting the voltage value at the time of regenerative when the regenerative condition is satisfied, your preset The regenerative time ratio calculation means for counting the time of the regenerative processing within a given time and calculating the ratio of the regenerative time, and the voltage value to be set at the time of charging after the calculation according to the ratio of the regenerative time And an hourly voltage value setting means.

  The battery management apparatus for a vehicle according to the present invention can manage the battery easily and accurately, and can manage the battery balance appropriately in consideration of regeneration to greatly improve fuel efficiency. It becomes possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 8 show an embodiment of the present invention, FIG. 1 is a schematic explanatory diagram of an entire vehicle having a vehicle battery management device, FIG. 2 is a flowchart of battery management control, and FIG. 3 is a battery current value and temperature. FIG. 4 is a time chart showing an example of changes in the voltage value and current value of the battery after idling stop, and FIG. 5 is variable depending on the current value and temperature of the battery. FIG. 6 is a time chart showing an example of changes in the voltage value and current value of the battery after the start of regeneration, and FIG. 7 is a graph showing the characteristics of the overcharge threshold value set. FIG. 8 is a characteristic diagram of the voltage value at the time of regeneration commanded to the inverter set in accordance with the engine speed and the brake depression force.

  In FIG. 1, reference numeral 1 denotes an engine disposed in the front part of the vehicle, and driving force by the engine 1 is transmitted from an automatic transmission device (including a torque converter and the like) 2 behind the engine 1 to a transfer 3. .

  Further, the driving force transmitted to the transfer 3 is input to the rear wheel final reduction device 7 via the rear drive shaft 4, the propeller shaft 5, and the drive pinion shaft portion 6, while the reduction drive gear, the reduction driven gear, the front It is input to the front wheel final reduction gear (the front drive system is not shown) via the drive shaft.

  The driving force input to the rear wheel final reduction gear 7 is transmitted to the left rear wheel 9rl through the rear wheel left drive shaft 8rl and to the right rear wheel 9rr through the rear wheel right drive shaft 8rr. The driving force input to the front wheel final reduction gear is transmitted to the left front wheel 9fl via the front wheel left drive shaft 8fl and to the right front wheel 9fr via the front wheel right drive shaft 8fr.

Next, each electronics system mounted on this vehicle will be described.
This vehicle has two voltage systems of a 42V high voltage system and a 14V low voltage system.

  Reference numeral 11 denotes an inverter device. In the inverter device 11, the crank sprocket 12 of the engine 1 rotates the pulley 14 at the end of the rotating shaft via the belt 13 to generate electric power, and at the same time the power is not regenerated at the time other than the initial start-up. A motor / generator 15 for starting the engine 1 in starting or the like is electrically connected.

  The inverter device 11 is connected to a 42V system wiring connected to a chargeable / dischargeable 36V battery 16, and the 42V system wiring is connected to the starter motor 17 used only at the time of the first engine start, or the electric motor power. A steering device 18 and the like are connected.

  Further, a 42V system wiring is connected to the side surface of the inverter device 11, and a DC-DC converter 19 for converting a 42V voltage into a 14V voltage is provided substantially integrally therewith. A chargeable / dischargeable 12V battery 20 is connected to the wiring connected to the DC-DC converter 19, and other various lamps, audio, and a 14V load 21 such as each control device to be described later are connected.

  The vehicle is equipped with an idle stop control device 30 that mainly performs automatic stop / restart control of the vehicle. The idle stop control device 30 includes an engine control device 31 that executes various well-known controls in the engine 1. The battery management device 32 that mainly manages the charging state and discharging state of the 36V battery 16 is connected by, for example, a CAN (Controller Area Network) which is one of ISO standard protocols as a vehicle communication network. .

  The idle stop control device 30 includes a brake pedal depression amount sensor 42 (which may detect brake hydraulic pressure) that detects a depression stroke of the brake pedal 41, and an accelerator pedal depression amount sensor 44 that detects a depression stroke of the accelerator pedal 43. It is connected. Further, the idle stop control device 30 includes a handle angle sensor 45 for detecting the handle angle θH, a vehicle speed sensor 46 for detecting the vehicle speed V, and selected shift positions (P, R, N, D, 3rd speed, 2nd speed, A shift position switch 47 for detecting each range position of the first speed, an engine speed sensor 48 for detecting the engine speed NE, and the like are connected. The signals obtained by these switches and sensors are transmitted to the battery management device 32 as necessary, in particular, the brake depression force obtained by the brake pedal depression amount sensor 42, the engine speed, and the like.

  Then, the idle stop control device 30 determines whether or not a preset engine automatic stop condition is satisfied based on information obtained from these switches and sensors, and the engine automatic stop condition is satisfied. If the engine is in the idle state, a signal is output to the engine control device 31 to cause the engine 1 to stop automatically.

  Further, the idle stop control device 30 outputs a signal to the engine control device 31 and the inverter device 11 to drive the motor / generator 15 when the engine automatic stop condition is not satisfied in the idle stop state. 1 is restarted. Here, the engine automatic stop condition is, for example, that the brake pedal 41 is depressed, the accelerator pedal 43 is not depressed, and the shift position is P, N, D, 3rd speed, 2nd speed, 1st speed. This is a case where the vehicle speed V is substantially zero and there is no idle stop prohibition command from the battery management device 32.

  Further, the idle stop control device 30 is configured so that the regeneration condition set in advance (for example, the accelerator pedal 43 is not depressed, the engine speed NE is 1000 rpm or more, the vehicle speed V is 40 km / h or more, the drive system) And the engine 1 are connected and the fuel is not consumed), a regeneration command is output to the battery management device 32. That is, the idle stop control device 30 has a function as a regeneration condition determination unit.

  The battery management device 32 detects the temperature of the 36V battery 16 in order to manage the charge state and the discharge state of the 36V battery 16 according to the flowchart shown in FIG. The battery voltmeter 52 for detecting the battery current and the battery ammeter 53 for detecting the current value of the 36V battery 16 are connected.

  When charging, the battery management device 32 outputs the target voltage value to the inverter device 11 without directly controlling the power generation torque of the motor / generator 15, and executes the charging. Since charging is performed by regeneration or the like, charging is normally performed with a voltage value corresponding to a preset battery remaining capacity of 70%. The voltage value output to the inverter device 11 at the normal time is equal to or greater than a predetermined ratio (for example, a time ratio of 5%) for a predetermined time (for example, 3 to 5 minutes) before performing the normal charging. If the regenerative state is being counted, the voltage value corresponding to the ratio of the regenerative time is determined for a predetermined time (for example, 3 to 5 minutes) of normal charging with reference to a preset map. It is supposed to be set. That is, the battery management device 32 is configured to have functions as regeneration executing means, regeneration time ratio calculating means, and normal time voltage value setting means.

  Further, when there is a regeneration command from the idle stop control device 30, a higher voltage value is set to the inverter device 11 in accordance with the engine speed and the brake pedal force, as the engine speed is higher and the brake pedal force is larger. Output.

  Further, when it is determined from the voltage value of the 36V battery 16 that the 36V battery 16 is in an overdischarged state, the battery management device 32 outputs an idle stop prohibition command to the idle stop control device 30 as described later. Furthermore, a rapid charging process is executed to perform charging at a voltage value that is higher than the normal charging voltage value by a predetermined value, thereby suppressing the discharge state.

  Further, when it is determined from the current value of the 36V battery 16 that the 36V battery 16 is in an overcharged state, the battery management device 32 does not cut off the power generation by the motor / generator 15 as will be described later. In addition, a charging suspension process for setting a voltage value lower than the predetermined value is executed.

  Next, battery management control in the battery management device 32 will be described with reference to the flowchart of FIG. First, in step (hereinafter abbreviated as “S”) 101, parameters necessary for control are read, and the process proceeds to S102 to determine whether or not the 36V battery 16 is in an overdischarged state.

  Specifically, first, as shown in FIG. 3, the overdischarge threshold value Vc1 is determined by referring to the map of the overdischarge threshold value Vc1 corresponding to the current value and temperature of the 36V battery 16 stored in advance. The overdischarge threshold value Vc1 is compared with the voltage value of the 36V battery 16 to determine whether or not the overdischarge state is set. The overdischarge threshold value Vc1 is set to a higher value as the temperature becomes higher, and is set to a lower value because the voltage drop becomes larger as the current value becomes higher.

  In other words, as shown in the example of the time chart of FIG. 4, when the engine 1 is idle-stopped at time t0 and the discharge continues at a constant current value, the voltage value of the 36V battery 16 gradually decreases. Then, when the decrease in the voltage value tries to fall below the overdischarge threshold value Vc1 (time tvc1), the 36V battery 16 is determined to be in the overdischarge state.

  As a result of the determination in S102, when it is determined that the 36V battery 16 is in an overdischarged state, the process proceeds to S103, and an idle stop prohibition command is output to the idle stop control device 30 to suppress discharge.

  Next, the process proceeds to S104, and a quick charging process for the 36V battery 16 is performed. This is a voltage value that is higher than a predetermined voltage value (which may be a value that is variably set according to temperature) that corresponds to a preset battery remaining capacity of 70%, which is a target for normal charging (for example, , + 2V) is output to the inverter device 11 to perform charging. If the quick charging process is performed for a too long time, the temperature of the 36V battery 16 may rise and be activated too much, so it is desirable to perform the process only for about 10 minutes.

  Then, the process proceeds to S105, in which it is determined whether or not the voltage value of the 36V battery 16 has reached an intermediate state, that is, a voltage value corresponding to a preset battery remaining capacity of 70% that is a target for normal charging. If the intermediate state has not been reached, the quick charging process of S104 is executed again, and if the intermediate state has been reached, the process proceeds to S112.

  On the other hand, when it is determined in S102 that the 36V battery 16 is not in the overdischarged state, the process proceeds to S106, and it is determined whether or not the 36V battery 16 is in the overcharged state.

  Specifically, first, as shown in FIG. 5, the overcharge threshold Ic1 is set by referring to the map of the overcharge threshold Ic1 corresponding to the voltage value and temperature of the 36V battery 16 stored in advance. The overcharge threshold Ic1 is compared with the current value of the 36V battery 16 to determine whether or not the battery is in an overcharge state. The overcharge threshold value Ic1 is set to a higher value as the temperature becomes higher, and a larger current flows as the voltage value becomes higher. Therefore, the overcharge threshold value Ic1 is set to a higher value.

  That is, as shown in the example of the time chart of FIG. 6, charging by regeneration is started at time t0, and when a constant voltage value is set and charging of the 36V battery 16 starts, it gradually flows into the 36V battery 16. The current value becomes smaller. When the decrease in the current value is about to fall below the overcharge threshold Ic1 (time tic1), the 36V battery 16 is determined to be in an overcharge state.

  As a result of the determination in S106, if it is determined that the 36V battery 16 is in the overcharged state, the process proceeds to S107, and the charging suspension process of the 36V battery 16 is performed. This is because the voltage value corresponding to the battery remaining capacity of 70% set as a target for normal charging is not completely cut off, but is set to 50% set in advance. The voltage is output to the inverter device 11 so as to be charged with a voltage value corresponding to the remaining battery capacity (which may be a value variably set according to the temperature).

  Then, the process proceeds to S108, in which it is determined whether or not the voltage value of the 36V battery 16 has reached an intermediate state, that is, a voltage value corresponding to a preset battery remaining capacity of 70% that is a target for normal charging. If the intermediate state has not been reached, the charging suspension process of S107 is executed again, and if the intermediate state has been reached, the process proceeds to S112.

  If it is determined in S106 that the 36V battery 16 is not in an overcharged state, the process proceeds to S109, where it is determined whether there is another abnormal state. If there is no state, the process proceeds to S112. This other abnormality is, for example, a case where the voltage value, current value, or temperature of the 36V battery 16 shows a value that cannot be taken normally. If there is such an abnormality, the process proceeds to S110. Normalization processing, for example, execution of a self-diagnosis program for confirming the connection of the battery temperature sensor 51, the battery voltmeter 52, and the battery ammeter 53 is performed, and the process proceeds to S111.

  In S111, it is confirmed whether or not the normal state has been restored. If the normal state has not been restored, the process returns to S110 to perform the necessary normalization process again. Proceed to S112.

  When the process proceeds from any of S105, S108, S109, and S111 to S112, it is determined whether or not a regeneration command is output from the idle stop control device 30. If the regeneration command is not output, the process proceeds to S113, and the normal voltage value is set according to the ratio of the regeneration time. The voltage value set here means that the regenerative state of a predetermined ratio (for example, a time ratio of 5%) or more is counted for a predetermined time (for example, 3 to 5 minutes) before performing the normal charging. If it is, the predetermined charging time (for example, 3 to 5 minutes) during normal operation is based on a preset map as shown in FIG. Set a high voltage value at times, and set a low voltage value during operation with a large proportion of regeneration time. Further, after the charging for the predetermined time, a voltage value corresponding to a preset battery remaining capacity of 70% is set. According to this map, the set voltage value increases and the amount of charge increases when the operating state has a low regenerative time ratio, and the set voltage value increases when the operating state has a high regenerative time ratio. It becomes lower and the charge amount becomes smaller.

  And it progresses to S114 and outputs to the inverter apparatus 11 so that it may charge with the voltage value set by S113, and a program is exited.

  On the other hand, when the regeneration command is output from the idle stop control device 30, the process proceeds to S115, and as shown in FIG. 8, according to the engine speed and the brake pedaling force with reference to a preset map, The higher the engine speed, the higher the brake pedal force, the higher the voltage value is set and output to the inverter device 11 to exit the program. That is, according to the characteristics of the map of FIG. 8, when the engine speed is low or the brake pedal force is low, the regenerative voltage is kept low, so that excessive shock and deceleration acceleration do not occur, which is inconvenient to the passenger. There is no pleasure. In addition, when the engine speed is high or when the brake pedal force is large, a large deceleration acceleration can be tolerated.By setting the regenerative voltage higher, more energy can be regenerated, resulting in improved fuel efficiency. effective.

  As described above, according to the battery management device 32 according to the embodiment of the present invention, the target voltage value for normal charging is charged with a voltage value corresponding to a preset battery remaining capacity of 70%. As a result, it is possible to manage the battery of a vehicle that is frequently regenerated and idle-stopped and charged / discharged at all times, simply by determining its voltage value and taking into account complex calculations and many parameters. It is possible to carry out accurately with less error. Further, since frequent regeneration and idle stop are possible, it is possible to greatly improve fuel consumption. For example, when the target voltage value for charging is a value close to full charging, it may be assumed that overcharging occurs due to an error, and when full charging is targeted, energy is regenerated. There are many situations where this is not possible, and there is a possibility that improvement in fuel efficiency cannot be expected. On the contrary, when the target voltage value for charging is too low, it may be difficult to smoothly restart after the idle stop if the idle stop is frequently performed. Thus, if charging is performed with a voltage value corresponding to a preset battery remaining capacity of 70%, such a problem does not occur.

  In addition, according to the present embodiment, the voltage value output to the inverter device 11 at the normal time is set high to increase the amount of charge in the operation state where the ratio of the regeneration time is small, and the ratio of the regeneration time When operating with a lot of energy, the amount of charge is controlled by setting it low, so that energy during regeneration can be efficiently recovered, and energy loss for charging during normal operation is minimized. Therefore, it is possible to further improve the fuel consumption.

  Furthermore, according to the present embodiment, during regeneration, when the engine speed is low or when the brake pedal force is small, the regenerative voltage is kept low, so that excessive shock and deceleration acceleration do not occur, and the occupant Does not give any discomfort. In addition, when the engine speed is high or when the brake pedal force is large, a large deceleration acceleration can be tolerated.By setting the regenerative voltage higher, more energy can be regenerated, resulting in improved fuel efficiency. effective. Depending on the specifications of the vehicle, the regenerative voltage may be set only by either the engine speed or the brake pedal force.

  Further, according to the present embodiment, the overdischarge state of the 36V battery 16 can be determined simply by comparing the voltage value with the overdischarge threshold value Vc1, so the overdischarge state of the 36V battery 16 is Without taking into account complicated calculations and many parameters, it is possible to accurately determine with little error, and it is possible to reliably prevent deterioration of the durability of the 36V battery 16 and deterioration of the restartability of the idle stop vehicle. ing. When an overdischarge state of the 36V battery 16 is detected, an idle stop prohibition command is output so that the discharge state can be reliably suppressed. Further, by performing the quick charging process, it is possible to reliably prevent the performance deterioration of the 36V battery 16 in preparation for a vehicle stop or the like.

  Furthermore, according to the present embodiment, since the overcharge state of the 36V battery 16 can be determined simply by comparing the current value with the overcharge threshold Ic1, the overcharge state of the 36V battery 16 is determined as follows. Without taking into account complicated calculations and many parameters, it is possible to accurately determine with little error, and it is possible to reliably prevent the durability and reliability of the 36V battery 16 from deteriorating. When an overcharged state of the 36V battery 16 is detected, a voltage corresponding to a preset battery remaining capacity of 70%, which is a target for normal charging, that is, a charging suspension process of the 36V battery 16 is performed. The output is output to the inverter device 11 so as to charge at a voltage value corresponding to a preset battery remaining capacity of 50%, instead of completely cutting the charge. Thus, by setting the power generation voltage to be lowered, the 36V battery 16 is rapidly discharged, and a charge acceptance amount can be secured. In addition, since the power generation by the motor / generator 15 is not completely cut off, the 36V battery 16 can be protected from sudden electrical load fluctuations, and the shock caused by the ON / OFF of the power generation can be reduced. Comfort can be kept good.

Schematic explanatory diagram of an entire vehicle having a vehicle battery management device Battery management control flowchart Characteristics diagram of overdischarge threshold variably set according to battery current value and temperature Time chart showing an example of changes in battery voltage and current after idle stop Overcharge threshold characteristic diagram variably set according to battery current value and temperature Time chart showing an example of changes in battery voltage and current after starting regeneration Characteristic diagram of normal voltage value commanded to inverter set according to regenerative time ratio Characteristic diagram of voltage value during regeneration commanded to inverter set according to engine speed and brake pedal force

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 11 Inverter apparatus 15 Motor / generator 16 36V battery 30 Idle stop control apparatus (regenerative condition determination means)
31 Engine control device 32 Battery management device (regeneration execution means, regeneration time ratio calculation means, normal time voltage value setting means)
51 Battery temperature sensor 52 Battery voltmeter 53 Battery ammeter
Agent Patent Attorney Susumu Ito

Claims (2)

In a battery management device for a vehicle that operates an inverter device connected to a generator based on a voltage value to be set and performs constant voltage charging on the battery,
Regenerative condition determining means for determining whether a preset regenerative condition is satisfied according to the driving state of the vehicle;
A regenerative braking unit for executing a regeneration process by setting the voltage value at the time of regenerative when the regenerative condition is satisfied,
Regeneration time ratio calculating means for counting the time of the regeneration process within a preset time and calculating the ratio of the regeneration time;
A normal voltage value setting means for determining the voltage value to be set at the time of charging after the calculation according to the ratio of the regeneration time;
A vehicle battery management apparatus comprising: 2. The vehicle battery according to claim 1, wherein the normal voltage value setting means sets a voltage value corresponding to the ratio of the regeneration time only during a preset time at the time of charging. Management device.

Images