JP4158887B2 - Electric vehicle power supply device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply device for an electric vehicle equipped with an electric motor for driving wheels and a battery, and more particularly, a power supply device for an electric vehicle capable of ensuring a longer traveling distance of the electric vehicle at the end of discharge of the battery. About.
[0002]
[Prior art]
Conventionally, an electric vehicle travels by supplying electric power from a battery to an electric motor that drives wheels, and can travel until an amount of electric power corresponding to the remaining battery capacity is discharged.
[0003]
In such an electric vehicle power supply device, the discharge stop voltage value is set as the lower limit of the terminal voltage of the battery, and the electric motor is secured in order to secure the current necessary for the battery while preventing overdischarge of the battery. The maximum discharge current value is set as the upper limit of the discharge current value supplied to the.
[0004]
According to this electric vehicle, the vehicle travels while being controlled so that the discharge current value from the battery is less than or equal to the maximum discharge current value during traveling, and when the terminal voltage value of the battery is less than or equal to the discharge stop voltage value, By stopping the running of the battery, overdischarge of the battery can be prevented.
[0005]
[Problems to be solved by the invention]
However, in this electric vehicle, if the discharge current increases at the end of the remaining battery level, such as when starting or climbing, the terminal voltage of the battery becomes lower than the discharge stop voltage value. There was a problem that the car stopped running.
[0006]
In particular, in storage batteries such as lead storage batteries, nickel storage batteries, and lithium storage batteries, internal resistance tends to increase due to deterioration when used for a long period of time, and apparent internal resistance tends to increase at low temperatures, so the remaining battery capacity remains. However, there is a risk that the electric vehicle may suddenly stop in an unexpected place when discharging a large current such as when starting or climbing a hill.
[0007]
Therefore, an object of the present invention is to provide a power supply device for an electric vehicle that can effectively use the remaining amount of battery and can ensure a long travel distance as much as possible.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, which solves the above problem, includes a motor controller capable of adjusting power supplied from a battery to an electric motor, and includes a detection unit that detects a terminal voltage value and a discharge current value of the battery, The motor controller controls the discharge current value of the detection unit to be equal to or lower than a first maximum discharge current value set in advance, and the terminal voltage value of the battery is reduced to a predetermined discharge stop voltage value or lower. An electric vehicle power supply apparatus that is controlled to stop energization sometimes when the motor controller detects a terminal voltage value equal to or lower than the discharge stop voltage value in the detection unit. with value is controlled to be less than the first maximum discharge current value is smaller than the second maximum discharge current value, the discharge to be equal to or less than the second maximum discharge current value After the flow value is controlled, when the terminal voltage value equal to or lower than the discharge stop voltage value is detected again, the discharge current value is controlled to be equal to or smaller than the third maximum discharge current value smaller than the second maximum discharge current value. characterized in that it.
[0010]
Furthermore, the invention described in claim 2 is provided with a battery remaining amount display unit in addition to the configuration described in claim 1 , and is controlled so that the discharge current value is equal to or less than the second maximum discharge current value. In some cases, the display unit is controlled so that the remaining battery level is present.
[0011]
The invention according to claim 3 is characterized in that, in addition to the configuration according to claim 1 or 2 , the discharge stop voltage value is set to decrease as the discharge current value increases. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0013]
1 to 4 are diagrams showing an embodiment of the present invention.
[0014]
In the figure, reference numeral 10 denotes an electric vehicle, a motor driving force transmission system from an electric motor 13 is connected to a transmission 12 for driving a rear wheel 11, and an internal combustion engine 16 from a combustion engine 16 is connected via a clutch 15. The engine driving force transmission system is connected to form a so-called hybrid vehicle.
[0015]
An electric power supply device 17 is connected to the electric motor 13. Here, electric power from a battery 18 made of a lead storage battery is adjusted by a motor controller 19 and supplied to the electric motor 13. . The battery 18 may be a nickel storage battery or a lithium storage battery.
[0016]
In addition, a battery management controller (hereinafter abbreviated as BMC) 22 is connected to the motor controller 19, and the opening degree of the accelerator pedal 10 a, the selection of the switch 14 a of the control panel 14, and the vehicle speed sensor 20 of the transmission 12. Is input to the BMC 22, and the motor controller 19 is controlled by the BMC 22 by communication according to these.
[0017]
The BMC 22 is configured to receive detection values such as a terminal voltage value E _t of the battery 18, a discharge current value I _d , and a battery temperature detected by the battery state detection unit 21. Further, the remaining battery level obtained from the detection value of the battery state detection unit 21 is displayed on the display unit 14 b of the operation panel 14.
[0018]
Furthermore, this BMC22, discharge stop voltage E _L as the lower limit of the terminal voltage E _t for preventing the over-discharge of the battery 18 is set, as the upper limit for controlling the discharge current value I _d of the battery 18 a first maximum discharge current value _{I H1,} a first maximum discharge current value _{I H1} smaller than the second maximum discharge current value _{I H2,} a second maximum discharge current value _{I H2} is smaller than the third maximum discharge current value _{I H3} Is set.
[0019]
And here, when the discharge stop voltage E _L following terminal voltage E _t is detected by the battery state detecting unit 21, the discharge current value I _d is the first maximum discharge current value I _H1 smaller than the second maximum discharge It controls the motor controller 19 so as not to exceed the current value I _H2, furthermore, upon detection of a discharge stop voltage E _L below the terminal voltage value E _t again, the discharge current value I _d is the second maximum discharge current value I _The motor controller 19 is controlled so as to be equal to or smaller than the third maximum discharge current value I _H3 smaller than _H2 .
[0020]
On the other hand, in the internal combustion engine 16, the throttle valve 24 a of the carburetor 24 is configured to be opened and closed by the throttle motor 25, and the electric power from the battery 18 is adjusted by the motor driver 26 and supplied to the throttle motor 25. The opening degree of the valve 24a is adjusted. The opening degree of the throttle valve 24 a is transmitted from the sensor 27 to the BMC 22.
[0021]
A BMC 22 is connected to the motor driver 26, and the motor driver 26 is controlled by the BMC 22 in accordance with the opening degree of the accelerator pedal 10a, the selection of the switch 14a, the vehicle speed, and the like.
[0022]
The driving force from the internal combustion engine 16 is transmitted to the transmission 12 by operating the clutch 15 by the BMC 22 as necessary. The torque at this time is detected by the torque sensor 28 and input to the BMC 22.
[0023]
The internal combustion engine 16 is connected to a generator 31 and can generate power by rotating the generator 31 during operation. The generated power is supplied to the battery 18 via the generator controller 32 and the switch 33 so that the battery 18 can be charged. The current value and voltage value of the electric power supplied from the generator 31 are transmitted to the BMC 22 by communication, and further, the rotational speed of the generator 31 is transmitted from the rotational speed sensor 23 to the BMC 22, and a signal from the BMC 22 based on this is transmitted. In response, the motor driver 26 and the generator controller 32 are adjusted to control power generation and charging.
[0024]
Next, the traveling state of the electric vehicle 10 will be described.
[0025]
The electric vehicle 10 travels by driving the rear wheels 11 using the driving force from the motor driving force transmission system by the electric motor 13 and the driving force from the internal combustion engine driving force transmission system by the internal combustion engine 16. . Here, the driving force from the electric motor 13 and the driving force from the internal combustion engine 16 are selectively switched or used together as necessary. For example, when the load calculated from the opening of the accelerator 10a or the difference between the target vehicle speed and the actual detected vehicle speed is smaller than a predetermined value, the vehicle travels with the driving force from the electric motor 13 and the load is large. The driving force from the internal combustion engine 16 is used together with the driving force from the electric motor 13.
[0026]
In this traveling, when the driving force of the internal combustion engine 16 is used, the generator 31 rotates and the battery 18 is charged. Further, when the traveling using the driving force from the electric motor 13 is continued, the power of the battery 18 is consumed, and the remaining amount of the battery is reduced. Therefore, when the remaining amount of the battery becomes a predetermined value or less, The generator 31 is rotated by the internal combustion engine 16 and the battery 18 is charged.
[0027]
When the battery 18 deteriorates and the internal resistance increases, the amount of charge of the battery 18 and the amount of electric power consumed by the electric motor 18 do not match each other during traveling, and the electric power consumption progresses, eventually reaching the end of the remaining battery level. May reach.
[0028]
Therefore, in the power supply device 17 of the electric vehicle 10, the power supplied to the electric motor 18 is controlled by the BMC 22 and the motor controller 19 in the final state where the remaining battery level is low.
[0029]
This control flow will be described with reference to FIGS.
[0030]
First, after the start of traveling, in step S1, the first maximum discharge current value I _H1 is selected, and the discharge current value I _d detected by the battery state detection unit 21 is equal to or less than the first maximum discharge current value I _H1. Thus, the electric motor 18 is driven to travel. When the discharge in the range of the discharge current value I _d of normal operation to continue, the terminal voltage value E _t detected by the battery state detecting unit 21 gradually decreases. When the terminal voltage E _t is larger than the discharge stop voltage value E _L , step S2 is repeated. When the terminal voltage E _t further decreases, the terminal voltage value E _t becomes equal to or less than the discharge stop voltage value E _L at time t1. Then, the process proceeds from step S2 to step S3, and the first maximum discharge current value I _H1 is set to a second maximum discharge current value I _H2 smaller than this.
[0031]
Although conventional terminal voltage E _t is an electric vehicle is stopped immediately running when it becomes less than the discharge stop voltage value E _L, in the electric vehicle 10, from the first maximum discharge current value I _H1 in Step S3 Since the second maximum discharge current value I _H2 that is small and smaller than the discharge current value I _d at this time is selected, traveling can be continued. That is, this change in the second maximum discharge current value I _H2, since the second maximum discharge current value I _H2 than the discharge current value I _d is suppressed prevents larger, the terminal voltage E _t is 3 recovered as shown, a discharge stop voltage E _L greater than. As a result, the discharge current value I _d is such that the second than the maximum discharge current value I _H2, by controlling the power by the motor controller 19 from BMC22, it is possible to continue the running of the electric vehicle 10.
[0032]
At this time, the terminal voltage value E _t detected by the battery state detecting unit 21, as shown in the characteristic curve of FIG. 3, but changes so as to rapidly reduced and recovery, of the display portion 14b of the operation panel 14 Battery level display of is controlled so as to change slowly than the change in the terminal voltage E _t on the basis of a signal from BMC22. For this reason, the remaining battery level is displayed until the terminal voltage value _Et rapidly decreases and recovers.
[0033]
Then, the discharge current value I _d to be detected by the battery state detecting unit 21 continues to travel in such a manner that a second or less maximum discharge current value I _H2, further advances the consumption of power, again the terminal voltage E _t is descend. When the terminal voltage E _t is larger than the discharge stop voltage value E _L , step S4 is repeated. When the terminal voltage E _t further decreases, the terminal voltage value E _t becomes equal to or lower than the discharge stop voltage value E _L again at time t2. . Then, the process proceeds from step S4 to step S5, and in this step S5, the third maximum discharge current value I _H3 smaller than the second maximum discharge current value I _H2 and smaller than the discharge current value I _d at this time is selected. . Thus, further discharging current value I _d is kept small, again the terminal voltage E _t recovered as shown in FIG. 3, larger than the discharge stop voltage E _L. As a result, by controlling the motor controller 19 by BMC22 as discharging current value I _d becomes equal to or less than the third maximum discharge current value I _H3, electric vehicle 10 is enabled to further continue traveling. Even at this time, the display unit 14b of the operation panel 14 is controlled to display the remaining battery level.
[0034]
When the discharging current value I _d to be detected by the battery state detecting unit 21 continues to travel as the following third maximum discharge current value I _H3, even further advances the consumption of power, the battery level indicator consumption reduced according to the amount, again terminal voltage E _t decreases. At this time the terminal voltage E _t is larger than the discharge stop voltage E _L, step S5 is repeated and further decreases, at time t3, again, the terminal voltage value E _t is less discharge stop voltage E _L. Then, the process proceeds from step S5 to step S6. In step S6, the power supply from the battery 18 is stopped, the battery fuel gauge display is set to 0, and the running of the electric vehicle 10 is ended.
[0035]
In the power supply device 17, in the following predetermined discharge current value I _b, the set discharge stop voltage E _L in BMC22 is, as shown in FIG. 4, E _a with the increase of the discharge current value I _d E _b until is set to decrease at a constant rate, and has a discharge stop voltage E _L having an inclination in accordance with the discharge current value I _d from. That is, as the discharge current value I _d becomes larger, the discharge stop voltage E _L is low, difficult to reach a discharge stop voltage E _L when the load of the electric motor 13 is large, the running of the electric vehicle 10 is stopped It has become difficult.
[0036]
According to the electric vehicle 10 having the configuration of a power supply device 17 as described above, when detecting a discharge stop voltage E _L below the terminal voltage value E _t by the battery state detecting unit 21, the discharge current value I since _d is controlled to be a first maximum discharge current value I _H1 smaller than the second below the maximum discharge current value I _H2, the terminal voltage value E _t reaches below the discharge stop voltage value E _L decreases also, to recover the terminal voltage value E _t by suppressing the discharge current value I _d, a discharge stop voltage E _L is greater than the terminal voltage E _t can be ensured. Therefore, the supply of electric power from the battery 18 to the electric motor 13 can be continued, whereby the remaining amount of the battery 18 can be effectively used to further improve the performance of the battery 18 and extend the travel distance of the electric vehicle 10. Is possible.
[0037]
In particular, when the internal resistance of the battery 18 that has deteriorated after being used for a long time is increased, or when the apparent internal resistance is increased at a low temperature, the remaining amount of the battery 18 is effectively used. Thus, since the travel distance of the electric vehicle 10 can be extended, it is easy to prevent the electric vehicle 10 from stopping at an unexpected place when discharging a large current such as when starting or climbing.
[0038]
Also, after controlling the discharge current value I _d to the second than the maximum discharge current value I _H2, upon detection of the discharge stop voltage E _L below the terminal voltage value E _t again, the discharge current value I _d the remaining amount of but for controlled to be less than the second maximum discharge current value I _H2 is smaller than the third maximum discharge current value I _H3, can be repeatedly performed to recover the terminal voltage E _t, more effectively battery 18 It is possible to maximize the performance of the battery 18 and extend the travel distance of the electric vehicle 10 by using.
[0039]
Furthermore, the remaining battery capacity displayed on the operation panel 14, when the discharge current value I _d is controlled to be a second maximum discharge current value I _H2 below or third or less than the maximum discharge current value I _H3, battery and controls the display unit 14b of the operation panel 14 so the remaining amount exists, that terminal voltage value E _t of the battery 18 is reached below the discharge stop voltage E _L, which displays the appropriate battery level It is possible to match the display of the remaining battery level and the actual remaining battery level.
[0040]
In addition, this invention is not limited to said embodiment, It can change suitably, For example, in said embodiment, as electric vehicle 10, both electric motor 13 and internal combustion engine 16 are used as a drive source. Although the hybrid vehicle used has been described, the present invention can be applied to a vehicle without the internal combustion engine 16 or an electric vehicle without the generator 31 mounted thereon.
[0041]
In the above embodiment, an example in which the second and third maximum discharge current values I _H2 and I _H3 are set in addition to the first maximum discharge current value I _H1 has been described. The number can be selected as appropriate, and may be two of the first maximum discharge current value I _H1 and the second maximum discharge current value I _H2 , and four or more maximum discharge current values can be set. In any case, the smallest maximum discharge current value can be set to a minimum current value at which the electric vehicle 10 can travel.
[0042]
【The invention's effect】
As described above in detail, according to the present invention, when the motor controller detects a terminal voltage value equal to or lower than the discharge stop voltage value in the detection unit, the discharge current value is smaller than the first maximum discharge current value. Since the discharge current value is controlled to be equal to or less than the discharge current value, even if the terminal voltage value decreases and reaches the discharge stop voltage value or less, by suppressing the discharge current value, the terminal voltage value is recovered to be less than the discharge stop voltage value. A large terminal voltage value can be secured. Therefore, it is possible to continue the supply of electric power from the battery to the electric motor, and thereby it is possible to effectively use the remaining amount of the battery and extend the travel distance of the electric vehicle.
[0043]
In addition, after the discharge current value is controlled to be equal to or lower than the second maximum discharge current value, when the terminal voltage value equal to or lower than the discharge stop voltage value is detected again, the discharge current value is smaller than the second maximum discharge current value. 3. Since control is performed so that the value is less than the maximum discharge current value, the terminal voltage value can be repeatedly recovered, the remaining battery capacity can be used more effectively, and the mileage of the electric vehicle can be further extended. Is possible.
[0044]
Furthermore, according to the invention of claim 2 , the battery remaining amount display unit is provided, and when the discharge current value is controlled to be equal to or lower than the second maximum discharge current value, the remaining battery amount is present. Since the display unit is controlled, an appropriate remaining battery level can be displayed even if the terminal voltage of the battery reaches the discharge stop voltage value or less, and the remaining battery level and actual battery level can be displayed. It is possible to match the amount.
[0045]
According to the invention described in claim 3 , since the discharge stop voltage value is set to decrease as the discharge current value increases, the discharge stop voltage value is set when the load on the electric motor is large. It becomes difficult to reach, and it can be made difficult to stop the traveling of the electric vehicle.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an electric vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a control flow of the electric vehicle power supply apparatus according to the embodiment;
FIG. 3 is a graph showing changes in a terminal voltage value and a discharge current value in a control state of the electric vehicle power supply apparatus according to the embodiment;
FIG. 4 is a graph showing a discharge stop voltage value of the electric vehicle power supply apparatus according to the embodiment;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electric vehicle 13 Electric motor 14 Operation panel 16 Internal combustion engine 17 Electric power supply device 18 Battery 19 Motor controller 21 Battery state detection part 22 Battery management controller (BMC)
31 Generator

Claims (3)

A motor controller capable of adjusting the power supplied from the battery to the electric motor is provided, a detection unit for detecting the terminal voltage value and the discharge current value of the battery is provided, and the discharge current value of the detection unit is preset by the motor controller Of the electric vehicle that is controlled so as to be less than or equal to the first maximum discharge current value that is set, and to stop energization when the terminal voltage value of the battery falls below a preset discharge stop voltage value. A power supply device,
When the motor controller detects a terminal voltage value less than or equal to the discharge stop voltage value, the motor controller causes the discharge current value to be less than or equal to a second maximum discharge current value that is smaller than the first maximum discharge current value. and controls on,
After the discharge current value is controlled to be equal to or less than the second maximum discharge current value, when the terminal voltage value equal to or less than the discharge stop voltage value is detected again, the discharge current value is the second maximum discharge current value. A power supply device for an electric vehicle, which is controlled to be smaller than a smaller third maximum discharge current value . A battery remaining amount display unit is provided, and when the discharge current value is controlled to be equal to or less than the second maximum discharge current value, the display unit is controlled so that the battery remaining amount exists. The electric vehicle power supply device according to claim 1 . The electric power supply apparatus for an electric vehicle according to claim 1 or 2 , wherein the discharge stop voltage value is set to decrease as the discharge current value increases.

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