KR101537093B1 - electric vehicle and control method thereof - Google Patents

Abstract

The present invention relates to an electric vehicle and a control method thereof. An electric vehicle according to the present invention includes a plurality of battery modules including a plurality of battery cells, a plurality of monitoring units for monitoring voltages of the battery modules, a plurality of battery modules connected to the battery modules, And a controller for transmitting a voltage balancing command to a corresponding balancing circuit that performs voltage balancing of a specific battery module based on the current consumption data received by the plurality of monitoring units.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric vehicle and a control method thereof, and more particularly to an electric vehicle and a control method thereof for performing battery cell balancing on the basis of a current value consumed by each of a plurality of monitoring units constituting a battery management system .

Research is actively being made in the sense that electric vehicles are the most likely alternative to solve future automobile pollution and energy problems.

BACKGROUND ART Electric vehicles (EVs) are mainly classified into battery-dedicated electric vehicles and hybrid electric vehicles, which are powered by an AC or DC motor using battery power, And the hybrid electric vehicle operates the engine to charge the battery by generating electric power and drive the electric motor by using the electric power.

The hybrid electric vehicle can be classified into a serial system and a parallel system. In the serial system, the mechanical energy output from the engine is converted into electrical energy through the generator, and the electrical energy is supplied to the battery or the motor. This is a concept that adds an engine and a generator to increase the mileage of an existing electric vehicle. The parallel method can move the car with battery power. The two motors (gasoline or diesel) Depending on the driving conditions, the parallel system can drive the vehicle at the same time as the engine and the motor.

Also, recently, motor / control technology is gradually developed, and high power, compact and highly efficient system is being developed. As the DC motor was converted into an AC motor, the output power and EV power performance (acceleration performance, maximum speed) were greatly improved, reaching a level comparable to that of gasoline cars. As high output was promoted, the weight of the motor was reduced and the weight and volume of the motor were greatly reduced.

In the case of such an electric vehicle, a battery pack composed of a plurality of battery cells is mounted to receive the required electric power. The plurality of battery cells included in such a battery pack needs to be uniform in voltage of each battery cell in order to obtain safety, life span, and high output. Thereby, a battery management system is used which allows each battery to have an appropriate voltage while charging or discharging the battery cells.

However, there is a difference between the currents consumed by each of the plurality of monitoring units constituting the battery management system, and this difference in the current consumption results in a voltage imbalance among the battery cells.

Therefore, there is a need for a cell balancing method that takes into account the current consumption of each of the plurality of monitoring portions.

It is therefore an object of the present invention to provide an electric vehicle and a control method thereof for performing cell balancing on the basis of consumption current values of respective voltage monitoring units that monitor the voltage of each battery cell.

According to an aspect of the present invention, there is provided an electric vehicle including: a plurality of battery modules including a plurality of battery cells; a plurality of monitoring units for monitoring voltages of the battery modules; And a controller for transmitting a voltage balancing command to a corresponding balancing circuit that performs voltage balancing of a specific battery module based on the current consumption data received by the plurality of monitoring units and balancing circuits for balancing the voltages of the modules .

According to another aspect of the present invention, there is provided a control method for an electric vehicle, comprising: measuring current consumption values of each of a plurality of monitoring units; comparing the current consumption values to determine a specific battery module requiring voltage balancing; Sending a command to a corresponding balancing circuit that performs voltage balancing of the module, and balancing the voltage of the particular battery module.

The electric vehicle and its control method according to the present invention can increase the voltage balancing efficiency between a plurality of battery modules including a plurality of battery cells.

Accordingly, the mileage of the electric vehicle and the battery life can be increased.

1 is a view schematically showing an internal configuration of an electric vehicle according to an embodiment of the present invention.
FIG. 2 illustrates a battery and battery management system of an electric vehicle according to an embodiment of the present invention. Referring to FIG.
3 is a flowchart showing a control method of an electric vehicle according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described with reference to the drawings for explaining an electric vehicle and a control method thereof according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described with reference to the drawings for explaining an electric vehicle and a control method thereof according to embodiments of the present invention.

1 is a schematic view illustrating an internal configuration of an electric vehicle according to an embodiment of the present invention.

1, an electric vehicle according to an embodiment of the present invention includes a vehicle control unit (VCM) 110, a motor control unit (MCU) 120, a motor 130, an interface unit 140, a power relay unit (PRA) 150, a battery 160, a battery management system (BMS) 170, and a sensor unit 180.

As described above, the electric vehicle operates by using the electric power charged in the battery 160 including the battery 160 as an operation power source, and is supplied with electric power from a predetermined charging station, ).

The battery 160 may store a high voltage electrical energy and may include a plurality of battery modules including a plurality of battery cells. For example, eight to ten battery cells may be connected in series to form one battery module. At this time, the electric vehicle controls the charging of the battery 160, determines the remaining capacity of the battery 160, necessity of charging, and carries out management in accordance with supply of the charging current stored in the battery 160 to each part of the electric vehicle And a battery management system (BMS) 170.

The battery management system 170 includes a plurality of voltage monitoring units (not shown) for monitoring the voltage of each battery module and a voltage balancing unit (not shown) connected to each of the plurality of battery modules, The voltage difference between the battery modules in the battery can be maintained evenly. Therefore, the life of the battery 160 can be extended by controlling the battery 160 to be neither overcharged nor overdischarged.

A method for balancing the voltage between the battery modules will be described in detail later with reference to FIG. 2 and FIG.

In addition, the voltage monitoring unit in the battery management system 170 may measure the battery remaining amount and the battery voltage of the battery 160 and transmit the battery remaining amount and the battery voltage to the vehicle control unit 110.

A power relay assembly (PRA) 150 applies or disconnects a plurality of relays and a high-voltage operation power applied from the battery 160, including a sensor, to the motor control unit 120 to switch a high voltage . At this time, the power relay unit 150 operates the relay by a control command of the vehicle control unit 110. [

The power relay unit 150 switches the plurality of relays in accordance with a control command of the vehicle control unit 110 when the vehicle is started or when the vehicle is turned off, So that the operation power of the high voltage stored in the power source is applied.

The power relay unit 150 can cut off the power applied from the battery 160 to the motor control unit 120 and the power supplied to the motor 130 is cut off so that the motor 130 is stopped, do.

The motor control unit 120 generates a control signal for driving at least one motor 130 connected to the motor control unit 120, and generates and applies a predetermined signal for motor control. At this time, the motor control unit 120 may control an operation of the motor 130 by controlling an inverter or a converter including an inverter (not shown) and a converter (not shown).

A vehicle control module (VCM) 110 controls the entire vehicle driving and operation. The vehicle control unit 110 generates and applies a predetermined command to the motor control unit 120 so as to perform an operation corresponding to the input of the sensor unit (not shown), and controls input and output of data.

Further, the vehicle control unit 110 monitors the output voltage of the battery 160 to control the running of the vehicle.

The sensor unit 180 detects a signal generated during a vehicle running or a predetermined operation and inputs the detected signal to the vehicle controller 110. The sensor unit 180 includes a plurality of sensors inside and outside the vehicle to input various sensing signals. At this time, the type of the sensor may be different depending on the installed position. The sensor unit 180 includes a wheel sensor for sensing the speed of the wheel for calculating the torque value, and a slope sensor for detecting the inclination of the vehicle.

The sensor unit 180 includes a plurality of sensors and may measure the input current of the motor 130 and the rotor angle of the motor (not shown) and transmit the measured value to the motor control unit 120.

The interface unit 140 includes input means for inputting a predetermined signal by the operation of the driver and output means for outputting information during the current operation of the electric vehicle to the outside.

The input means includes operating means for operation such as a steering wheel, an accelerator, and a brake. The accelerator outputs acceleration information for torque value calculation, and the brake outputs braking information for torque value calculation.

Further, the input means includes a plurality of switches, buttons, and the like for operation of a turn signal lamp, a tail lamp, a head lamp, a brush, etc.,

The output means includes a display unit for displaying information, a speaker for outputting music, an effect sound and a warning sound, and various states.

FIG. 2 illustrates a battery and battery management system of an electric vehicle according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 2, the battery 160 may include a plurality of battery modules. One battery module includes a plurality of battery cells, and a plurality of battery cells are connected in series by a predetermined number to constitute n battery modules including a first battery module 161 and a second battery module 162 can do. For example, eight to ten battery cells can constitute one battery module, and the number of battery cells included in one battery module and the number of battery modules included in the battery 160 are not limited.

The battery management system 170 may include a plurality of monitoring units for monitoring each of the plurality of battery modules. For example, the first monitoring unit 171 for monitoring the first battery module 161, the second monitoring unit 172 for monitoring the second battery module 162, and the n-th battery module 163 are monitored And an n-th monitoring unit 173. Therefore, the number of battery modules and the number of monitoring parts can be the same.

Each monitoring unit can measure the voltage, current, and temperature of each connected battery module. At this time, the monitoring unit operates by receiving power from the battery module.

For example, the monitoring unit can measure the voltage of the battery module using a switching element, a resistor, a capacitor, and the like, and the measured voltage can be converted into a digital signal through analog-to-digital conversion.

In addition, the monitoring part can measure the consumption current of the monitoring part itself.

The measured data of the voltage, current, temperature, and consumption current of the battery module can be transmitted to the vehicle controller 110, and the data can be transmitted to the vehicle controller 110 in a daisy- .

The daisy chain method is a method in which the first monitoring unit 171 measures the first data (voltage, current, temperature, current consumption of the first monitoring unit, and the like) measured by the first monitoring unit 171, Lt; / RTI > The second monitoring unit 172 monitors the received first data and the second data measured by the second monitoring unit 172 (voltage, current, temperature, consumption current of the second monitoring unit, etc.) 3 Monitoring unit (not shown). In this manner, the nth monitoring unit 173 can receive the accumulated data (first data + second data +? + N-1 data) from the (n-1) th monitoring unit (not shown).

The n-th monitoring unit 173 outputs the final data (first data + second data +? N-1 data + n-th data) obtained by combining the received data and the n-th data measured by the n-th monitoring unit 173 To the vehicle control unit 110.

The vehicle control unit 110 may determine a specific battery module requiring balancing based on the received final data, and may transmit a driving command to the balancing circuit connected to the determined battery module.

Particularly, when the data of each monitoring unit is transmitted to the vehicle control unit 110 in the same manner as described above, there is a difference in the amount of data processed in each monitoring unit, and accordingly there is a difference in consumption current consumed in the monitoring unit .

For example, since the nth monitoring unit 173 processes the final data obtained by adding the first data, the second data, the?, The n-1 data, and the nth data, the first monitoring unit 173, The current consumption can be increased as compared with the case 171.

As described above, the difference in the consumption current of the monitoring unit, which is supplied with power from the battery module, may cause a voltage difference of the battery module.

Therefore, the vehicle control unit 110 can determine a specific battery module requiring balancing based on the consumption current data of each monitoring unit received, and transmit the drive command to the balancing circuit connected to the determined battery module. This will be described in detail later with reference to FIG.

On the other hand, the vehicle control unit 110 can be powered by a battery other than the battery 160, for example, a vehicle battery. In this case, the monitoring unit may include a monitoring unit for receiving power from the battery 160 and an isolator 190 for separating power from the vehicle control unit 110, which is supplied with power from a separate battery.

Also, although not shown, the vehicle control unit 110 can communicate with other control units in the vehicle to control the running of the vehicle.

3 is a flowchart showing a control method of an electric vehicle according to an embodiment of the present invention.

Referring to FIG. 3, each of the plurality of monitoring units measures the consumption current of the monitoring unit (S210). The measured consumption current value may be transmitted to the vehicle control unit 110. [ At this time, each monitoring unit can be transmitted to the vehicle control unit 110 by the daisy chain method described with reference to FIG. For example, the first monitoring unit 171 measures the current consumption value of the first monitoring unit 171 and transmits the measured current consumption value to the second monitoring unit 172. The second monitoring unit 172 monitors the first The consumption current value of the monitoring unit 171 and the consumption current value of the second monitoring unit 172 measured by the second monitoring unit 172 can be transmitted to the third monitoring unit (not shown). In this manner, the nth monitoring unit 173 can transmit the consumption current values of the first monitoring unit 171 to the nth monitoring unit 173 to the vehicle controller 110.

The vehicle control unit 110 may compare the consumption current values of the respective monitoring units to determine a specific battery module to perform voltage balancing (S220).

At this time, the specific battery module may be a battery module corresponding to a monitoring unit having a consumed current value that differs from the largest consumed current value by more than a reference value as a result of comparing consumption current values of the respective monitoring units.

Alternatively, the battery module may correspond to the monitoring unit having the smallest current consumption value as a result of the comparison. The criteria for determining a particular battery module is not limited thereto and may be determined on various criteria.

When the specific battery module is determined, the vehicle controller 110 may transmit a command to the corresponding balancing circuit that performs voltage balancing of the determined specific battery module (S230).

The corresponding balancing circuit receiving the command may perform voltage balancing for a specific battery module (S240).

At this time, voltage balancing for a specific battery module can perform balancing by discharging a specific battery module, lowering the voltage or consuming energy.

For example, the battery module corresponding to the monitoring unit having the smallest current consumption value may have the largest voltage, and therefore balancing can be performed by lowering the voltage to balance with other battery module voltages.

As described above, when the voltage balancing of the battery module is performed based on the consumption current value of each monitoring unit, the voltage unbalance caused by the consumption current difference consumed in the monitoring unit can be prevented.

Therefore, the voltage balancing efficiency between the plurality of battery modules can be increased, thereby increasing the mileage and battery life of the electric vehicle

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

110: vehicle control unit 120: motor control unit
130: motor 140:
150: power relay unit 160: battery
170: Battery management system 180:

Claims (13)

A plurality of battery modules including a plurality of battery cells;
A plurality of monitoring units for monitoring a voltage of each of the battery modules;
A plurality of balancing circuits connected to each of the battery modules, for balancing a voltage of the battery module; And
And a controller for transmitting a voltage balancing command to a corresponding balancing circuit that performs voltage balancing of a specific battery module based on consumption current data received by the plurality of monitoring units,
The specific battery module may be a battery module corresponding to a voltage monitoring unit having a consumption current value that is greater than a reference current value by a maximum consumption current value,
And a battery module corresponding to a voltage monitoring unit having a smallest current consumption value. The method according to claim 1,
The corresponding balancing circuit comprises:
And receives the command to discharge a specific battery module, thereby lowering the voltage. delete delete The method according to claim 1,
The corresponding balancing circuit comprises:
And balancing is performed until a voltage of the specific battery module reaches a reference voltage. The method according to claim 1,
The corresponding balancing circuit comprises:
Wherein the balancing is performed during the reference time. The method according to claim 1,
Further comprising an isolator for separating power from the control unit and the monitoring unit. Measuring current consumption values of each of the plurality of monitoring units;
Comparing the consumption current values to determine a specific battery module requiring voltage balancing;
Transmitting a command to a corresponding balancing circuit that performs voltage balancing of the determined specific battery module; And
And balancing the voltage of the particular battery module,
The determining may comprise determining the battery module corresponding to the monitoring unit having the largest consumption current value and the consumed current value that is different from the reference value by the specific battery module,
Wherein the battery module corresponding to the monitoring unit having the smallest current consumption value is determined as the specific battery module. 9. The method of claim 8,
In balancing the voltage of the specific battery module,
And discharging the specific battery module to lower the voltage. delete delete 9. The method of claim 8,
In balancing the voltage of the specific battery module,
And balancing the voltage until the voltage of the specific battery module reaches the reference voltage. 9. The method of claim 8,
In balancing the voltage of the specific battery module,
And balancing the voltage during the reference time.

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