KR101601713B1 - Apparatus and method for battery cell balancing - Google Patents

Abstract

The present specification relates to an apparatus and a method for battery cell balancing in a battery management system which can prevent the overheating of a battery cell balancing circuit in a battery management system. According to an embodiment of the present specification, the battery cell balancing apparatus comprises: a battery module including a plurality of battery cells; a storage unit where a voltage threshold value of the battery cell is set and stored; and a control unit connected to the battery module, and monitoring and controlling the charging and discharging status of battery cells of the battery module. The control unit calculates average voltage by measuring voltage of the battery cells, determines whether two or more cells are adjacent to each other or not by selecting two or more cells having a voltage value exceeding the threshold value set and stored in the storage unit among the battery cells, and controls to sequentially discharge the cells in descending order of voltage when two or more cells are determined to be adjacent.

Description

[0001] APPARATUS AND METHOD FOR BATTERY CELL BALANCING [0002]

The present invention relates to a battery management system that can be used in an apparatus using electric energy. In particular, the present invention relates to a cell balancing apparatus and method for increasing the efficiency of a battery in a high voltage battery management system used in hybrid vehicles and electric vehicles.

In recent years, various devices such as industrial devices, home appliances and automobiles using high-voltage batteries have appeared, and especially in the field of automobile technology, the use of high-voltage batteries is becoming more active.

Automobiles that use internal combustion engines that use fossil fuels such as gasoline or heavy oil as the main fuel have a serious impact on pollution such as air pollution. Therefore, in recent years, efforts have been made to develop an electric vehicle or a hybrid vehicle in order to reduce pollution.

Electric vehicles (EVs) are vehicles that do not use petroleum fuels and engines but that use electric batteries and electric motors. That is, an electric vehicle that drives an automobile by rotating an electric motor that is accumulated in a battery is developed prior to a gasoline automobile, but is not commercialized because of problems such as a heavy weight of the battery, a limitation of the capacity of the battery, And environmental problems became serious, research for commercialization began in the 1990s.

On the other hand, hybrid technology (HEV) that uses electric vehicles, fossil fuels and electric energy adaptively is being commercialized as battery technology has been developed remarkably. Since HEV uses gasoline and electricity together as a power source, it is evaluated positively in terms of fuel efficiency improvement and exhaust gas reduction, and it is expected to play an intermediate role in evolving into a fully electric vehicle.

Since HEV and EV vehicles using such electric energy use a battery in which a plurality of rechargeable secondary cells are packed as a main power source, there is no exhaust gas and noise is small. have.

Since the performance of a battery using the electric energy directly affects the performance of the vehicle, it is necessary to measure the voltage of each battery cell, the voltage and current of the entire battery, and to efficiently manage charge and discharge of each battery cell However, a battery management system (BMS) is required to monitor the state of a cell sensing IC that senses each battery cell, thereby enabling stable control of the corresponding cell.

1 is a block diagram schematically showing a battery management system according to the prior art.

Referring to FIG. 1, a vehicle battery management system 100 includes a battery stack 10 including a plurality of battery modules, a vehicle electronic device 20, and a battery control device 30.

The battery stack 10 includes a plurality of battery modules 11 and 12, and the battery modules 11 and 12 include a plurality of battery cells. The battery stack 10 supplies the charged high voltage direct current power to the vehicle electronic device 20 such as a motor.

The battery control device 30 may include a plurality of MCUs 31 and 32 and a BCU 33 for controlling the MCU. The battery control device 30 is connected to the battery stack to monitor the charge / discharge state of the battery stack 10, and controls the charge / discharge operation of the battery stack 10. [

As described above, in a battery management system combining a plurality of battery cells, a voltage deviation between battery cells due to a structural difference necessarily occurs. Such a voltage deviation hinders the uniformity of the battery voltage, and eventually acts as a cause of battery deterioration, thereby reducing the life of the battery.

Therefore, the battery cell balancing operation which maintains the voltage of each cell evenly during the operation of the system using the battery power or the charge / discharge of the battery cell becomes a very important element of the battery management system.

Japanese Patent Laying-Open No. 2014-17997 discloses a battery control device for a vehicle, which discharges a cell voltage higher than a lower cell voltage based on a battery cell balancing operation.

According to the above conventional technology, since all the cells except for the battery cell having the lowest voltage are balanced, an excessive heat is generated in the balancing circuit, so that the risk of fire and explosion is a problem. In addition, since excessive heat is generated in the balancing circuit, a problem arises in that high-end discharge resistance and peripheral elements must be used. In addition, there is a problem that the durability of the battery management system is deteriorated due to overheating of the battery related circuit.

Furthermore, the conventional battery management system has a limitation that the cell balancing operation must be performed only when the battery charger does not perform the charging operation.

Japanese Patent Application Laid-Open No. 2014-17997

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery cell balancing apparatus and method capable of preventing overheating of a battery cell balancing circuit in a battery management system.

It is also an object of the present invention to provide a battery cell balancing apparatus and method which are low in manufacturing cost and excellent in durability because overheating can be prevented even if a low-cost component is used.

It is another object of the present invention to provide a battery cell balancing apparatus and method capable of performing cell balancing even during a battery charging operation.

According to an embodiment of the present invention, a battery cell balancing apparatus includes: a battery module including a plurality of battery cells; A storage unit for storing a voltage threshold of the battery cell; And a controller connected to the battery module to monitor and control the charge / discharge state of the battery cells of the battery module, wherein the controller calculates an average voltage by measuring a voltage of the plurality of battery cells, The control unit selects at least two or more cells having a voltage value exceeding a threshold value set in the storage unit to determine whether the cells are adjacent to each other or to sequentially discharge the cells in the order of a higher voltage value .

The controller may determine whether the battery module is being charged when the battery cell exceeding the threshold value is selected, and stop the charging operation of the battery module when the battery module is being charged.

In addition, the controller may adaptively change a threshold value set in the storage unit according to an average voltage of the battery cells, reset the threshold, and store the threshold value in the storage unit.

Also, the controller may discharge the voltage of the highest voltage cell until it reaches the average voltage, then re-calculate the voltage of the plurality of battery cells to recalculate the average voltage, And the step of discharging is repeatedly performed until the voltage reaches the average voltage.

According to another aspect of the present invention, a cell balancing apparatus includes: a battery module including a plurality of battery cells; A storage unit for storing a voltage threshold of the battery cell; And a controller connected to the battery module to monitor and control the charge / discharge state of the battery cells of the battery module, wherein the controller calculates an average voltage by measuring a voltage of the plurality of battery cells, Numbered cells and the odd-numbered cells and the even-numbered cells are sequentially discharged when the cells are determined as adjacent cells by selecting at least two cells having a voltage value exceeding the threshold value set in the storage unit, .

The controller may determine whether the battery module is being charged when the battery cell exceeding the threshold value is selected, and stop the charging operation of the battery module when the battery module is being charged.

In addition, the controller may adaptively change a threshold value set in the storage unit according to an average voltage of the battery cells, reset the threshold, and store the threshold value in the storage unit.

Also, the controller may discharge the voltages of the odd-numbered battery cells until the voltage reaches the average voltage, re-calculate the average voltage by re-measuring the voltages of the plurality of battery cells, And discharging the battery cells repeatedly until the voltage of the battery cells reaches the average voltage.

A method of balancing battery cells according to an embodiment of the present invention is a method of balancing cells in a battery management system for a vehicle including a plurality of battery cells, the method comprising: measuring a voltage of the plurality of battery cells; Calculating an average voltage of the measured battery cells; Selecting a plurality of battery cells exceeding a voltage threshold of a predetermined battery cell among the battery cells; Determining whether the selected plurality of battery cells are adjacent to each other; And discharging the battery cells sequentially in order of increasing voltage when it is determined that a plurality of adjacent battery cells exist.

The discharging of the battery cell may include: determining whether the battery cells are being charged; Stopping the charging operation when charging is determined as a result of the determination; And sequentially discharging the voltage of the battery cell until the average voltage is reached.

The step of calculating the average voltage of the measured battery cells may further include the step of updating the voltage threshold value of the predetermined battery cell according to the calculated average voltage.

The discharging of the battery cell may include discharging until the voltage of the highest voltage cell reaches the average voltage, then re-calculating the voltage of the plurality of battery cells to recalculate the average voltage, And repeats the process of sequentially discharging until the voltage of the highest voltage cell reaches the average voltage.

According to another aspect of the present invention, there is provided a battery balancing method for a vehicle battery management system including a plurality of battery cells, the balancing method comprising: measuring a voltage of the plurality of battery cells; Calculating an average voltage of the measured battery cells; Selecting a plurality of battery cells exceeding a voltage threshold of a predetermined battery cell among the battery cells; Determining whether the selected plurality of battery cells are adjacent to each other; And controlling to sequentially discharge odd-numbered cells and even-numbered cells alternately when it is determined that a plurality of adjacent battery cells exist.

In the method, the battery cell selecting step may include: determining whether the battery cells are being charged; And stopping the charging operation if it is determined that the charging operation is being performed.

The step of calculating the average voltage of the measured battery cells may further include the step of updating the voltage threshold value of the predetermined battery cell according to the calculated average voltage.

The discharging of the battery cell may include discharging until the voltage of the odd-numbered battery cells reaches the average voltage, re-calculating the average voltage by re-measuring the voltage of the plurality of battery cells, And sequentially discharging the battery cells until the voltage of the even-numbered battery cells exceeds the average voltage.

According to an embodiment of the present invention, the present specification can prevent the overheat of the battery cell balancing circuit in the battery management system, thereby preventing the risk of fire and explosion of the high voltage battery.

In addition, the battery management system of the present invention performs cell balancing using the average voltage and the threshold voltage of the battery cells, thereby achieving a more efficient cell balancing operation and increasing the usable capacity of the battery.

In addition, according to the embodiment of the present invention, it is possible to prevent overheating even if a low-cost component is used, thereby providing a battery cell balancing apparatus and method with low manufacturing cost and excellent durability.

In addition, according to the embodiment of the present invention, it is possible to perform cell balancing even during the battery charging operation.

1 is a block diagram of a conventional battery management system.
2 is a block diagram of a battery management system in accordance with one embodiment of the present disclosure;
3 is a reference view illustrating an exemplary measured voltage of battery cells according to an embodiment of the present invention.
4 is a flowchart sequentially illustrating a battery cell balancing method according to an embodiment of the present invention.
5 is a flowchart illustrating a battery cell balancing method according to another embodiment of the present invention.
6 is a reference view exemplarily showing a measured voltage of battery cells according to another embodiment of the present invention.
7 is a flowchart sequentially illustrating a battery cell balancing method according to another embodiment of the present invention.
8 is a reference view exemplarily showing a measured voltage of battery cells according to another embodiment of the present invention.
9 is a flowchart sequentially illustrating a battery cell balancing method according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of techniques which are well known in the technical field to which this specification belongs and which are not directly related to this specification are not described. This is for the sake of clarity without omitting the unnecessary explanation and without giving the gist of the present invention.

For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In the drawings, the same or corresponding components are denoted by the same reference numerals.

Hereinafter, a battery management system according to an embodiment of the present invention will be described with reference to FIG.

2 is a block diagram of a battery management system in accordance with one embodiment of the present disclosure;

Referring to FIG. 2, a battery management system 200 according to an embodiment of the present invention includes a battery module 13 and a cell balancing device 40.

The battery module 13 includes a plurality of battery cells. For convenience of description, the description will be made on the assumption that four battery cells C1, C2, C3, and C4 are connected in series. The battery module 13 may be constituted by a plurality of battery modules. The battery module 13 supplies the charged high-voltage DC power to a motor provided in the vehicle, and receives a charging voltage through the charging device.

The cell balancing device 40 includes a storage unit 41 and a control unit 42. [

Each of the battery cells C1, C2, C3 and C4 may be connected to the discharging resistor R through switches S1, S2, S3 and S4 connected to the respective cells. Therefore, the cell balancing device 40 measures the voltage of each cell and controls the on / off operation of the switches S1, S2, S3 and S4 through the control part 42 when charge and discharge are required, And discharge operation.

A threshold voltage value (hereinafter referred to as a 'threshold value' or a 'threshold value') of the battery cell is set and stored in the storage unit 41. The threshold value of the battery cell is a reference voltage value determined to be able to reach a danger such as fire or explosion due to overcharging of the battery cell. According to an embodiment of the present invention, the battery capacity of the battery cell may vary depending on the electrochemical characteristics, the deterioration state, the ambient temperature, the usage conditions, and the like of the secondary battery. have. For example, if the voltage threshold set for the minimum battery cell is VT, the capacity due to frequent charging and discharging of the battery cell, or the ambient temperature of the battery cell is high, even if the cell voltage does not reach the threshold VT, There may be a risk of. Therefore, the threshold value of the battery cell stored in the storage unit 41 is updated periodically or adaptively in consideration of the average voltage value of the battery or the like.

According to another embodiment of the present invention, the 'VT' set to the initial voltage threshold of the battery cell is set to 3.75 V, which is the nominal voltage of the lithium ion battery, when the average voltage of the battery cells is 3.75 V or more Lt; RTI ID = 0.0 > VT. ≪ / RTI > However, if the average voltage of the battery cells is 3.75 V or less, which is the nominal voltage of the battery cell, the voltage value of the battery cell is compensated for by compensating for the difference to reset the voltage threshold value to VT and stored in the storage unit 41. As the battery ages, it tends to become lower without maintaining the nominal voltage of 3.75 V of the lithium ion battery. The aged battery has the characteristic that the overcharging and overdischarging occur more rapidly at the same charge / discharge current and the internal resistance increases have. Therefore, in the embodiment of the present invention, the threshold voltage of the battery cell is further lowered in consideration of such characteristics.

The control unit 42 monitors and controls the charging and discharging states of the plurality of battery cells of the battery module 13. That is, the control unit 42 monitors operation characteristics such as voltage, current, charge state, temperature, and the like of a plurality of battery cells. Also, the battery cell is controlled to be charged or discharged through a result of monitoring the plurality of battery cells. For example, when the charging voltage of the battery cell exceeds a predetermined charging threshold value, the battery cell is discharged through the switching operation.

According to an embodiment of the present invention, the controller 42 calculates the average voltage VA by measuring the voltages of the plurality of battery cells C1, C2, C3, and C4, and selects the highest voltage cell among the battery cells And determines whether the cell voltage value exceeds a preset threshold value VT stored in the storage unit 41. [ As a result of the determination, when the cell voltage value of the highest voltage cell exceeds the threshold value VT, discharge is performed until the voltage of the highest voltage cell reaches the average voltage VA.

That is, it is determined whether cell balancing is required by comparing the cell voltage value having a peak value with a threshold value. If a cell having a peak value is larger than the threshold value VT, the cell is discharged for balancing only for the cell. Thereafter, the cells having the peak value are checked one by one to repeat the discharging operation. Therefore, there is an advantage that a problem such as heat generated by simultaneous discharge of a plurality of cells as in the prior art is not generated in the present embodiment. Furthermore, since the cells to be discharged are selected based on the average voltage value VA of all the cells and the adaptive threshold value VT instead of selecting the cells to be discharged based on the lowest voltage cell, unnecessary or excessive cell balancing can be prevented.

According to another embodiment of the present invention, the control unit 42 calculates the average voltage VA by measuring the voltages of the plurality of battery cells, and determines the average voltage VA exceeding the threshold value VT set in the storage unit 41 At least one battery cell is selected, and at least one battery cell is discharged until the voltage of the selected battery cell reaches the average voltage VA.

That is, a plurality of cells exceeding the threshold VT are detected, and a discharge is simultaneously performed on the plurality of cells. Therefore, in this embodiment, a plurality of cells can be discharged simultaneously. In addition, instead of selecting the cells to be discharged based on the lowest voltage cell, the discharge target cells are selected based on the average voltage value of all the cells and the adaptive threshold value, so that unnecessary or excessive cell discharge can be prevented.

At this time, in order to prevent the occurrence of overheating even when a plurality of cells are simultaneously discharged, the controller 42 checks whether a plurality of cells exceeding the threshold VT are adjacent to each other. If a plurality of cells exceeding the threshold value VT are adjacent to each other, the cell having the peak voltage value is first discharged, and then the cell having the next peak voltage value is identified to discharge sequentially. (Or even-numbered cells) are discharged first, and the even-numbered cells (or odd-numbered cells) are sequentially discharged in the following order when a plurality of cells exceeding the threshold value VT are adjacent to each other, Thereby preventing the occurrence of overheating due to the simultaneous discharge of the adjacent cells even if discharged at the same time.

The cell balancing method according to the embodiment will be described in more detail with reference to FIG. 7 based on the case of FIG. 3 and FIG.

FIGS. 3 and 6 are reference views illustrating exemplary measured voltages of battery cells according to an embodiment of the present invention.

3, assuming that four cells C1, C2, C3, and C4 are connected in series, the measured voltages of the respective cells are VC1, VC2, VC3, and VC4, , And the average voltage of the four cells is VA.

At this time, it is assumed that the measured voltages VC1 and VC3 of the non-adjacent cells 1 and 3 exceed the threshold value VT, as shown in the figure. Therefore, it can be seen that cells 1 and 3 are in an overcharged state based on the measured cell voltage.

6, assuming that four cells C1, C2, C3 and C4 are connected in series, the measured voltages of the respective cells are V1, V2, V3 and V4, respectively, and the threshold of the cell voltage is VT , And the average voltage of the four cells is VA.

At this time, as shown, it is assumed that the measured voltages V3 and V4 of the adjacent cells 3 and 4 exceed the threshold value VT. Therefore, it can be seen that cells 3 and 4 are in an overcharged state based on the cell measurement voltage.

Cell balancing embodiments will be described in detail based on such a situation.

4 is a flowchart sequentially illustrating a battery cell balancing method according to an embodiment of the present invention.

First, the control unit 42 measures the voltage of the individual cells (S401), and calculates the average voltage VA of the four cells (S403).

Thereafter, the voltage of the highest voltage cell and the voltage of the corresponding cell are checked (S405), and it is determined whether the corresponding voltage value exceeds a predetermined threshold value VT (S407).

3, the control unit 42 compares the voltage VC3 of the cell 3 with the threshold VT based on the voltage VC3 of the cell 3 because the voltage value of the cell 3 has the highest peak value among all the cells. As a result of comparison, since the value of VC3 is larger than VT, the controller 42 determines that a discharge for cell balancing is necessary.

At this time, the controller 42 determines whether the battery module is being charged (S409). If the battery module is not being charged, the controller 42 starts discharging the highest voltage cell 3 (S413) After controlling to stop (S411) The discharge of the cell 3 can be started (S413).

Then, it is checked whether the voltage of the cell 3 reaches the target voltage value through discharge (S415). The target voltage value of the discharge cell may be set to the average voltage VA.

When the cell 3 reaches the target voltage VA through the discharging operation, the discharging of the cell 3 is stopped and the voltage is again fed back to the initial stage to calculate the individual voltage measurement S401 and the average voltage of the four cells (S403) .

In the case of FIG. 3 described above, since the voltage value of the cell 3 is changed to VA through discharging, the cell 1 having the next peak value will have the maximum value among all the cells. Therefore, the discharge is also performed to the cell 1 in the same manner as the discharge process of the cell 3. The cells having peak values are sequentially checked to discharge the cells, thereby preventing the problems such as heat generation caused by simultaneously discharging the cells.

5 is a flowchart illustrating a battery cell balancing method according to another embodiment of the present invention.

First, the control unit 42 measures the voltages of the individual cells (S501) and calculates the average voltage VA of the four cells (S503), as in the above-described embodiment.

Thereafter, it is determined whether cells C1 and C3 exist or not (S505).

3, since the voltage values VC1 and VC3 of the cell 1 and the cell 3 exceed the threshold value VT, the controller 42 selects the cell 1 and the cell 3 as cells to be discharged for cell balancing.

At this time, the controller 42 determines whether the battery module is being charged (S509). If the battery module is not being charged, the controller 42 simultaneously starts discharge of the cells 1 and 3 exceeding the threshold (S513) The charging operation of the battery module is stopped (S511), and the discharging of the cell 1 and the cell 3 can be started (S513).

Then, it is confirmed whether the voltages of the cell 1 and the cell 3 reach the target voltage value through the cell discharge through the switching control (S515). The target voltage value of the discharge cell may be set to the average voltage VA.

When the cell 1 and the cell 3 reach the target voltage VA through the discharging operation, the discharging of the cell 1 and the cell 3 is stopped and then fed back to the initial stage so that the individual voltage measurement S501 of the four cells and the average voltage (S503).

3, since the voltage values of the cells 1 and 3 exceeding the threshold value VT have been changed to VA through discharging, if the cell voltage value of the four cells is less than the threshold value VT No more cell balancing will be required. Therefore, according to the present embodiment, since a plurality of cells exceeding the threshold value VT can be discharged at one time, the cell balancing process can be performed more simply and quickly.

However, in the present embodiment, if a plurality of neighboring cells exceeds VT, a problem may occur due to overheating when all of the adjacent cells are discharged at the same time.

6, since the measured voltages V3 and V4 of the adjacent cells 3 and 4 of the four cells exceed the threshold value VT, the discharges of the cells 3 and 4 are required.

FIG. 7 is a flowchart sequentially illustrating a battery cell balancing method according to another embodiment of the present invention, and is a flowchart illustrating a cell balancing process of a plurality of adjacent cells as in the case of FIG.

First, the control unit 42 measures the voltages of the individual cells (S701) and calculates the average voltage VA of the four cells (S703).

Thereafter, it is determined whether cells C3 and C4 are present to exceed the preset threshold value VT (S705).

6, since the voltage values V3 and V4 of the cells 3 and 4 exceed the threshold value VT, the controller 42 selects the cells 3 and 4 as discharge target cells for cell balancing.

At this time, the control unit 42 determines whether the battery module is being charged. If the battery module is being charged, the control unit 42 controls to stop the charging operation of the battery module, and then starts discharging the cells 1 and 3.

On the other hand, the controller 42 determines whether the battery cells exceeding the threshold VT are adjacent cells (S709)

As a result of the determination in step S709, if the cell is not an adjacent cell, it is checked whether the voltage of the discharge cells reaches the target voltage value through the cell discharge through the switching control (S725). The target voltage value of the discharge cell may be set to the average voltage VA.

When the voltage of the discharge cells reaches the target voltage VA through the discharging operation, the discharge is stopped and the discharge is again fed back to the initial stage to calculate the individual voltage measurement S701 and the average voltage of the four cells (S703) .

As a result of the determination in step S709, if it is determined as an adjacent cell, the cell C3 having the highest cell voltage value is first selected and discharged (S713).

Then, it is confirmed whether the voltage of the battery cell C3 reaches the target voltage value (S715). The target voltage value of the discharge cell may be set to the average voltage VA.

When the voltage of the battery cell C3 reaches the target voltage VA through the discharging operation, the cell C4 having the next highest value is selected and discharged (S717).

Thereafter, it is confirmed whether the voltage of the battery cell C4 reaches the target voltage value, and the cells having the next highest value are sequentially selected to complete the discharge (S727). The subsequent steps are the same as those of the previously described embodiment, and a detailed description thereof will be omitted.

8 is a reference view exemplarily showing a measured voltage of battery cells according to another embodiment of the present invention.

8, assuming that eight cells C1, C2, C3, C4, C5, C6, C7 and C8 are connected in series, the measured voltages of the respective cells are V1, V2, V3, V4, V5, V6, V7, and V8, the threshold value of the cell voltage is VT, and the average voltage of the eight cells is VA.

At this time, it is assumed that the measured voltages V3 to V6 of the adjacent cells 3 to 6 exceed the threshold value VT as shown. Therefore, it can be seen that cells 3, 4, 5, and 6 of adjacent cells 4 are in an overcharged state based on the measured cell voltage.

FIG. 9 is a flowchart sequentially illustrating a battery cell balancing method according to another embodiment of the present invention, and is a flowchart illustrating a cell balancing process of a plurality of adjacent cells as in the case of FIG.

First, the control unit 42 measures the voltages of the individual cells (S701) and calculates the average voltage VA of the eight cells (S703).

Then, it is determined whether or not the cells C3, C4, C5, and C6 are present to exceed the preset threshold value VT (S705).

8, since the voltage values V3, V4, V5, and V6 of the cells 3 to 4 exceed the threshold value VT, the control unit 42 selects cells 3 to 4 as cells to be discharged for cell balancing.

At this time, the control unit 42 determines whether the battery module is being charged. If the battery module is being charged, the control unit 42 controls to stop the charging operation of the battery module, and then starts discharging the cells 3 to 6.

On the other hand, the controller 42 determines whether the battery cells exceeding the threshold VT are adjacent cells (S709)

As a result of the determination in step S709, if the cell is not an adjacent cell, it is checked whether the voltage of the discharge cells reaches the target voltage value through the cell discharge through the switching control (S725). The target voltage value of the discharge cell may be set to the average voltage VA.

When the voltage of the discharge cells reaches the target voltage VA through the discharge operation, the discharge is stopped and the discharge is again fed back to the initial stage to calculate the individual voltage measurement (S701) and the average voltage of eight cells (S703) .

As a result of the determination in step S709, if it is determined to be an adjacent cell, among them, C3 and C5, which are cell odd numbered cells, are first selected and discharged (S813).

Then, it is determined whether the voltages of the battery cells C3 and C5 reach the target voltage value (S715). The target voltage value of the discharge cell may be set to the average voltage VA.

When the voltage of the battery cells C3 and C5 reaches the target voltage VA through the discharging operation, the even-numbered battery cells C4 and C6 are selected and discharged (S817).

Thereafter, it is confirmed whether the voltages of the even-numbered battery cells C4 and C6 reach the target voltage value (S819), and the discharge is completed (S727). The subsequent steps are the same as those of the previously described embodiment, and a detailed description thereof will be omitted.

It will be understood by those skilled in the art that the present specification may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present specification is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present specification Should be interpreted.

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 embodiments, but, on the contrary, It is not intended to limit the scope of the specification. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100, 200: Battery management system (BMS) 10: Battery stack
11, 12, 13: battery modules C1, C2, C3, C4:
20: vehicle electronic device 30,40: battery control device
31, 32: MCU 33: BCU
41: storage unit 42: control unit
R: discharge resistor S1, S2, S3, S4: switch

Claims (16)

delete delete delete delete 1. A vehicle battery management system comprising:
A battery module including a plurality of battery cells;
A storage unit for storing a voltage threshold of the battery cell; And
And a controller connected to the battery module to monitor and control a charge / discharge state of battery cells of the battery module,
The controller calculates an average voltage by measuring a voltage of the plurality of battery cells and selects at least two or more cells having a voltage value exceeding a threshold value set in the storage unit of the battery cell to determine whether the cell is an adjacent cell Numbered cell and the even-numbered cell are sequentially discharged when the cells are determined to be adjacent to each other,
Numbered battery cells until the voltages of the odd-numbered battery cells reach the average voltage, re-calculating the average voltage by re-measuring the voltages of the plurality of battery cells, and calculating a voltage of the even- And repeating the discharging process sequentially until the re-measured average voltage is reached.
6. The apparatus of claim 5,
Wherein the control unit determines that the battery module is being charged when the battery cell exceeding the threshold value is selected and stops the charging operation of the battery module when the battery cell is being charged.
6. The apparatus of claim 5,
Wherein the threshold value set in the storage unit is adaptively changed according to an average voltage of the battery cells and is reset and stored in the storage unit.
delete delete delete delete delete 1. A cell balancing method for a battery management system for a vehicle including a plurality of battery cells,
Measuring a voltage of the plurality of battery cells;
Calculating an average voltage of the measured battery cells;
Selecting a plurality of battery cells exceeding a voltage threshold of a predetermined battery cell among the battery cells;
Determining whether the selected plurality of battery cells are adjacent to each other;
Discharging the odd-numbered cells until the average voltage is reached, if it is determined that a plurality of adjacent battery cells exist;
Remeasuring the average voltage of the battery cell; And
And discharging the even-numbered cells exceeding the threshold until the remeasured average voltage is reached.
14. The method as claimed in claim 13,
Determining whether the battery cells are being charged; And
And stopping the charging operation when the battery is being charged as a result of the determination.
14. The method of claim 13, wherein calculating the average voltage of the measured battery cells comprises:
And updating the voltage threshold of the predetermined battery cell according to the calculated average voltage.
delete

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