KR101856067B1 - Apparatus and method for diagnosing degree of sensing precision in battery management system - Google Patents

Abstract

The present invention relates to an apparatus and method for diagnosing a sensing accuracy of a battery management system, and more particularly, to a system and method for diagnosing a sensing accuracy of a battery management system, including a plurality of bus bars connecting a plurality of battery modules in series; A cell sensing unit having a plurality of sensing circuits for sensing voltages of the plurality of battery modules and the bus bar, respectively; A sensing command unit for outputting to the cell sensing unit a sensing command for sensing the voltage of the bus bar by the plurality of cell sensing circuits; A comparing unit comparing the voltage sensing value of the bus bar, which is sensed redundantly according to the output sensing command, with a preset error; And an accuracy diagnosing unit for discriminating a cell sensing circuit having a normal or abnormal accuracy among the plurality of cell sensing circuits according to a result of comparison between a voltage sensing value of the sensed bus bar and a predetermined error.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and a method for diagnosing sensing accuracy of a battery management system,

The present invention relates to an apparatus and method for diagnosing the accuracy of a battery management system, and more particularly, to an apparatus and method for diagnosing a sensing accuracy of a battery management system, The present invention relates to an apparatus and method for sensing accuracy of a battery management system capable of easily diagnosing variations in sensing accuracy between adjacent sensing units by comparing voltages of bars.

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.

Meanwhile, the plurality of battery modules 11 and 12 may be connected to each other by a bus bar. For example, the battery pack 10 may be composed of 72 battery cells. The battery pack 10 may be composed of nine battery modules composed of eight battery cells. The positive (+) terminal of the lower battery module and the negative (-) terminal of the upper battery module are electrically connected by bolts using a bus bar to connect between the battery module and the battery module. The bus bar can be made of a metal material that connects the battery module and the battery module together. Such a bus bar may have resistances of several m [Omega], for example, a conductor resistance itself and a contact resistance connecting battery modules to each other.

Japanese Patent Application Laid-Open No. 2014-17997

In embodiments of the present invention, the voltage of a bus bar connecting a plurality of battery modules in series is measured through a cell sensing unit adjacent to the bus bar, and the voltage of each measured bus bar is compared to determine a sensing precision deviation between adjacent sensing units And to provide an apparatus and method for sensing accuracy of a battery management system that can be easily diagnosed.

According to a first aspect of the present invention, there is provided a battery pack comprising: a plurality of bus bars connecting a plurality of battery modules in series; A cell sensing unit having a plurality of sensing circuits for sensing voltages of the plurality of battery modules and the bus bar, respectively; A sensing command unit for outputting to the cell sensing unit a sensing command for sensing the voltage of the bus bar by the plurality of cell sensing circuits; A comparing unit comparing the voltage sensing value of the bus bar, which is sensed redundantly according to the output sensing command, with a preset error; And a precision diagnostic unit for determining a cell sensing circuit having a normal or abnormal accuracy among the plurality of cell sensing circuits according to a result of comparison between a voltage sensing value of the sensed bus bar and a preset error, A diagnostic device may be provided.

The cell sensing unit may sense the voltage of the bus bar connected between the Nth and (N + 1) th battery modules via the lowest channel of the (N + 1) th sensing circuit and the highest channel of the Nth sensing circuit, respectively .

The comparator compares the voltage sensing value of the sensed bus bar with a predetermined error and determines whether the difference between the voltage sensing value of the Nth bus bar and the voltage sensing value of the N + 1th bus bar is less than a preset error have.

If the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the (N + 1) -th bus bar is less than a preset error, the precision diagnosis unit can determine the N-th and N + .

If the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the (N + 1) -th bus bar is equal to or greater than a predetermined error, the accuracy diagnosis unit includes a failure sensing circuit in the N-th and N + Can be distinguished.

When the abnormality sensing circuit is determined to be included in the Nth and (N + 1) th sensing circuits, the accuracy diagnosis unit determines that the difference between the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the If it is equal to or larger than the predetermined error, the (N + 1) th sensing circuit can be determined as a failure sensing circuit.

When the abnormality sensing circuit is determined to be included in the Nth and (N + 1) th sensing circuits, the accuracy diagnosis unit determines that the difference between the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the If it is less than the predetermined error, the (N + 1) th sensing circuit can be discriminated as the normal sensing circuit.

According to a second aspect of the present invention, there is provided a method for controlling a battery module, comprising: outputting a sensing command for sensing a voltage of a bus bar connecting a plurality of battery modules in series; Sensing a voltage of a plurality of bus bars connecting a plurality of battery modules in series according to the output sensing command; Comparing the voltage sensing value of the bus bar, which is overlapped with the sensed bus command, with a preset error; And diagnosing a sensing accuracy of the plurality of cell sensing circuits according to a result of comparison between a voltage sensing value of the sensed bus bar and a predetermined error.

The sensing of the voltages of the plurality of bus bars may include sensing a voltage of a bus bar connected between the Nth and (N + 1) th battery modules to a voltage of a most significant channel of the Nth sensing circuit, And can be respectively sensed through the lowest channel.

Comparing the voltage sensing value of the sensed bus bar with a predetermined error and comparing the voltage sensing value of the Nth bus bar and the voltage sensing value of the N + It can be confirmed whether or not it is less than the error.

If the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the (N + 1) -th bus bar is less than a predetermined error, the precision diagnosis unit determines the N-th and N + Th bus bar and the voltage sensing value of the (N + 1) th bus bar is equal to or greater than a predetermined error, it is possible to determine that the fault sensing circuit is included in the Nth and N + 1th sensing circuits.

The step of diagnosing the sensing accuracy includes: when the Nth and N + 1th sensing circuits are determined to include an abnormal sensing circuit, the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the If the difference between the values is equal to or greater than a predetermined error, the (N + 1) -th sensing circuit can be determined as a failure sensing circuit.

The step of diagnosing the sensing accuracy includes: when the Nth and N + 1th sensing circuits are determined to include an abnormal sensing circuit, the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the If the difference between the values is less than a preset error, the (N + 1) -th sensing circuit can be determined as a normal sensing circuit.

In embodiments of the present invention, the voltage of a bus bar connecting a plurality of battery modules in series is measured through a cell sensing unit adjacent to the bus bar, and the voltage of each measured bus bar is compared to determine a sensing precision deviation between adjacent sensing units It can be easily diagnosed.

1 is a block diagram schematically showing a battery management system according to the prior art.
2 is a configuration diagram of a bus bar diagnostic apparatus of a general battery management system.
3 is a configuration diagram of a sensing accuracy diagnostic apparatus of a battery management system according to an embodiment of the present invention.
4 is a flowchart illustrating a method of diagnosing a sensing accuracy of a battery management system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will be described in detail with reference to the portions necessary for understanding the operation and operation according to the present invention. In describing the embodiments of the present invention, description of technical contents which are well known in the art to which the present invention belongs and which are not directly related to the present invention will be omitted. This is for the sake of clarity of the present invention without omitting the unnecessary explanation.

In describing the constituent elements of the present invention, the same reference numerals may be given to constituent elements having the same name, and the same reference numerals may be given to different drawings. However, even in such a case, it does not mean that the corresponding component has different functions according to the embodiment, or does not mean that it has the same function in different embodiments, and the function of each component is different from that of the corresponding embodiment Based on the description of each component in FIG.

2 is a configuration diagram of a bus bar diagnostic apparatus of a general battery management system.

As shown in FIG. 2, a general bus management system bus-sensing apparatus includes a bus bar 111 and cell sensing units 110 and 120. Here, the cell sensing units 110 and 120 including the two sensing ICs for measuring the voltage of the bus bar 111 connected between the two battery modules will be described.

The plurality of battery modules are connected to each other by a bus bar 111. The bus bar 111 connects the battery module and the battery module. The positive (+) terminal of the lower battery module and the negative (-) terminal of the upper battery module are bolted and electrically connected.

The bus bar 111 is a conductive material for electrically connecting the high voltage battery module and the module, and is generally made of a metal material having a very low level of a few ohms or less.

The cell sensing units 110 and 120 include a sensing IC # 1 110 and a sensing IC # 2 120. Here, the cell sensing units 110 and 120 may be composed of a plurality of sensing ICs other than the two sensing ICs depending on the number of serial connections of the battery modules.

Since current flows through the bus bar when the battery pack is charged / discharged, both ends of the bus bar 111 are subjected to voltage. This voltage is generally measured in one channel of the upper or lower cell sensing unit 110 in the battery management system (BMS). The measured voltage value is used for bus bar diagnosis and the like.

3 is a configuration diagram of a sensing accuracy diagnostic apparatus of a battery management system according to an embodiment of the present invention.

3, the apparatus 200 for diagnosing a sensing accuracy of a battery management system according to an embodiment of the present invention includes a bus bar 111, cell sensing units 110 and 120, a sensing instruction unit 210, (220) and a precision diagnosis unit (230).

Hereinafter, the specific configuration and operation of each component of the sensing accuracy diagnostic apparatus 200 of the battery management system according to the embodiment of the present invention will be described.

The plurality of bus bars 111 connect a plurality of battery modules in series.

The cell sensing units 110 and 120 include a plurality of sensing circuits for sensing voltages of the plurality of battery modules and the bus bar 111, respectively. For example, the case where the battery module to be measured is the Nth, (N + 1) th, and N + 2th battery modules will be described.

The sensing command unit 210 outputs a sensing command to the cell sensing units 110 and 120 to sense a voltage of the bus bar 111 in a plurality of cell sensing circuits.

The cell sensing units 110 and 120 sense the voltage of the bus bar 111 connected between the Nth and (N + 1) th battery modules according to the sensing command output from the sensing instruction unit 210, And the lowest channel of the (N + 1) -th sensing circuit, respectively.

The comparator 220 compares the voltage sensing value of the bus bar 111, which is overlapped and sensed according to the sensing command output from the sensing commander 210, with a predetermined error.

The comparing unit 220 compares the voltage sensing value of the sensed bus bar 111 with a preset error and determines whether the difference between the voltage sensing value of the Nth bus bar and the voltage sensing value of the N + Check whether it is less than error.

The accuracy diagnosis unit 230 may determine a cell sensing circuit having a normal or abnormal accuracy among a plurality of cell sensing circuits according to a comparison result between a voltage sensing value of a bus bar sensed by the cell sensing units 110 and 120 and a preset error .

When the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the (N + 1) -th bus bar is less than a predetermined error, the precision diagnosis unit 230 determines the N-th and N + do.

When the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the (N + 1) -th bus bar is equal to or greater than a preset error, the accuracy diagnosis unit 230 outputs a failure sensing circuit .

When the abnormality sensing circuit is determined to be included in the Nth and (N + 1) th sensing circuits, the accuracy diagnosis unit 230 determines the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the Is greater than or equal to a preset error, the (N + 1) -th sensing circuit is determined as a failure sensing circuit.

When the abnormality sensing circuit is determined to be included in the Nth and (N + 1) th sensing circuits, the accuracy diagnosis unit 230 determines the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the Is less than a predetermined error, the (N + 1) -th sensing circuit is discriminated as a normal sensing circuit.

On the other hand, in the case of a battery pack (battery pack 0, which is made up of N battery modules), the sensing accuracy diagnosis apparatus 200 can compare the following as described below to find a sensing IC having a problem in accuracy. The order of the sensing IC is determined in the same manner as that of the battery module.

An example of discriminating a sensing IC having a precision problem will be described as follows, where the Nth sensing IC is the first sensing IC.

First, as a result of comparing the voltage of the bus bar sensed by the first sensing IC and the second sensing IC, the voltage deviation is within the set error range.

And the result of comparing the bus bar voltage sensed by the second sensing IC and the third sensing IC is that the voltage deviation is within the set error range.

The result of comparing the voltage of the bus bar sensed by the third sensing IC and the fourth sensing IC is that the voltage deviation is out of the set range of error.

The result of comparing the voltage of the bus bar sensed by the 4th sensing IC and the 5th sensing IC is that the voltage deviation is out of the error range set.

As a result of comparing the bus bar voltage sensed by the fifth sensing IC and the sixth sensing IC, the voltage deviation is within the error range set.

The sensing accuracy diagnostic apparatus 200 can confirm that there is a problem in the sensing accuracy of the fourth sensing IC based on the result of comparing the voltage deviation and the error.

4 is a flowchart illustrating a method of diagnosing a sensing accuracy of a battery management system according to an embodiment of the present invention.

The battery management system turns on the vehicle (IG On) (S101), and the sensing accuracy diagnostic apparatus 200 of the battery management system confirms the vehicle starting information on which the vehicle is turned on.

The sensing accuracy diagnostic apparatus 200 instructs the battery module of the battery management system to perform BMS sensing (S102).

The sensing accuracy diagnostic apparatus 200 proceeds with bus bar sensing (S103).

The sensing accuracy diagnostic apparatus 200 compares the sensed bus bar sensing values according to the bus bar sensing (S104).

The sensing accuracy diagnostic apparatus 200 determines that the voltage deviation between the voltage V (bus bar #N) of the Nth bus bar and the voltage V (bus bar # N + 1) of the (N + It is confirmed whether or not it is less than the set error (S105).

The voltage deviation between the voltage V (bus bar #N) of the Nth bus bar and the voltage V (bus bar # N + 1) of the (N + 1) If it is less than the error, the sensing accuracy diagnostic apparatus 200 determines that the sensing IC is an IC in a normal state (S106).

On the other hand, if the voltage deviation between the voltage V (bus bar #N) of the Nth bus bar and the voltage V (bus bar # N + 1) of the (N + 1) If the difference is equal to or larger than the predetermined error, the sensing accuracy diagnostic apparatus 200 determines the sensing IC as a sensing accuracy problem IC (S107).

Thereafter, the sensing accuracy diagnostic apparatus 200 determines a voltage deviation (voltage difference) between the voltage V (bus bar #N) of the Nth bus bar and the voltage V (bus bar # N + 1) Between the voltage V (bus bar # N + 1) of the (N + 1) th bus bar and the voltage V (bus bar # N + 2) of the Check that the voltage deviation is less than the predetermined error. At this time, the sensing accuracy diagnostic apparatus 200 confirms that the voltage deviation is equal to or higher than a preset error, and is an abnormal sensing IC (S108).

The sensing accuracy diagnostic apparatus 200 determines that there is a precision problem with the (N + 1) th sensing IC (IC (N + 1)) and determines that a fault has occurred (S109).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or essential characteristics thereof. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: Battery Management System (BMS)
10: Battery pack
11, 12, 13: Battery module
20: vehicle electronic device
30: Battery control device
31, 32: MCU
33: BCU
110, 120: cell sensing unit (sensing IC # 1, sensing IC # 2)
111: bus bar
200: Sensing accuracy diagnostic device
210: sensing command section
220:
230; Precision Diagnosis Department

Claims (13)

A plurality of bus bars connecting the plurality of battery modules in series;
A cell sensing unit having a plurality of sensing circuits for sensing voltages of the plurality of battery modules and the bus bar, respectively;
A sensing command unit for outputting to the cell sensing unit a sensing command for sensing the voltage of the bus bar by the plurality of cell sensing circuits;
A comparing unit comparing the voltage sensing value of the bus bar, which is sensed redundantly according to the output sensing command, with a preset error; And
And an accuracy diagnosis unit for determining a cell sensing circuit having a normal or abnormal accuracy among the plurality of cell sensing circuits according to a result of comparison between a voltage sensing value of the sensed bus bar and a predetermined error,
Wherein one end of one of the plurality of bus bars is connected to a first sensing circuit among the plurality of cell sensing circuits,
And the other end of the bus bar is connected to a second sensing circuit among the plurality of cell sensing circuits,
Wherein each of the first and second cell sensing circuits senses a voltage of any one of the bus bars. The method according to claim 1,
The cell sensing unit includes:
The sensing accuracy of the battery management system for sensing the voltage of the bus bar connected between the Nth and (N + 1) th battery modules through the lowest channel of the Nth sensing circuit and the lowest channel of the (N + 1) Device. The method according to claim 1,
Wherein,
Comparing the voltage sensing value of the sensed bus bar with a predetermined error, and determining whether the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the N + 1-th bus bar is less than a predetermined error Sensing accuracy diagnostic device. The method according to claim 1,
Wherein the precision diagnosis unit comprises:
If the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the N + 1-th bus bar is less than a predetermined error, the sensing accuracy of the battery management system for determining the N-th and Device. The method according to claim 1,
Wherein the precision diagnosis unit comprises:
The battery management system determines that a failure sensing circuit is included in the Nth and N + 1th sensing circuits when the difference between the voltage sensing value of the Nth bus bar and the voltage sensing value of the N + 1th bus bar is greater than a preset error, Sensing accuracy diagnostic device. 6. The method of claim 5,
Wherein the precision diagnosis unit comprises:
If it is determined that the Nth and N + 1th sensing circuits include an abnormal sensing circuit, if the difference between the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the (N + 2) , And the sensing accuracy of the battery management system for determining the (N + 1) th sensing circuit as a failure sensing circuit. 6. The method of claim 5,
Wherein the precision diagnosis unit comprises:
If it is determined that the Nth and N + 1th sensing circuits include an abnormal sensing circuit, if the difference between the voltage sensing value of the (N + 1) -th bus bar and the voltage sensing value of the (N + 2) -th bus bar is less than a predetermined error And an N + 1 < th > sensing circuit as a normal sensing circuit. Outputting a sensing command for sensing a voltage of a bus bar that connects a plurality of battery modules in series;
Sensing a voltage of a plurality of bus bars connecting a plurality of battery modules in series according to the output sensing command;
Comparing the voltage sensing value of the bus bar, which is overlapped with the sensed bus command, with a preset error; And
And diagnosing the sensing accuracy of the plurality of cell sensing circuits according to a result of comparison between a voltage sensing value of the sensed bus bar and a predetermined error,
Wherein one end of one of the plurality of bus bars is connected to a first sensing circuit among the plurality of cell sensing circuits,
And the other end of the bus bar is connected to a second sensing circuit among the plurality of cell sensing circuits,
Wherein each of the first and second cell sensing circuits senses a voltage of the bus bar. 9. The method of claim 8,
The step of sensing the voltages of the plurality of bus bars, respectively,
And the voltage of the bus bar connected between the Nth and (N + 1) th battery modules is sensed through the most significant channel of the Nth sensing circuit and the least significant channel of the (N + 1) th sensing circuit, respectively. 9. The method of claim 8,
Wherein the step of comparing the predetermined error with the predetermined error comprises:
A method of diagnosing a sensing accuracy of comparing a voltage sensing value of a sensed bus bar with a predetermined error, and determining whether a difference between a voltage sensing value of an Nth bus bar and a voltage sensing value of an N + 1th bus bar is less than a predetermined error . 9. The method of claim 8,
The step of diagnosing the sensing accuracy comprises:
If the difference between the voltage sensing value of the N-th bus bar and the voltage sensing value of the N + 1-th bus bar is less than a preset error, the Nth and N + 1th sensing circuits are determined to be in a normal state, And the voltage sensing value of the (N + 1) -th bus bar is greater than or equal to a predetermined error, it is determined that the failure sensing circuit is included in the Nth and N + 1th sensing circuits. 12. The method of claim 11,
The step of diagnosing the sensing accuracy comprises:
If it is determined that the Nth and N + 1th sensing circuits include an abnormal sensing circuit, if the difference between the voltage sensing value of the (N + 1) th bus bar and the voltage sensing value of the (N + 2) , And the sensing accuracy of the battery management system for determining the (N + 1) th sensing circuit as a failure sensing circuit. 12. The method of claim 11,
The step of diagnosing the sensing accuracy comprises:
If it is determined that the Nth and N + 1th sensing circuits include an abnormal sensing circuit, if the difference between the voltage sensing value of the (N + 1) -th bus bar and the voltage sensing value of the (N + 2) -th bus bar is less than a predetermined error , And the sensing accuracy of the battery management system for determining the (N + 1) -th sensing circuit as a normal sensing circuit.

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