KR101572650B1 - Apparatus and method for diagnosis of battery bank's imbalancing - Google Patents

Abstract

The present invention discloses an apparatus and method for diagnosing whether a battery bank is unbalanced. An apparatus for diagnosing a battery bank imbalance according to the present invention is an apparatus for diagnosing an imbalance of a battery pack in which a plurality of battery banks including battery cells electrically connected in parallel are serially connected, A current sensor for outputting a current value; A voltage sensor unit for measuring a voltage of each battery bank included in the battery pack and outputting a bank voltage value; And calculating a voltage change amount per time of each battery bank using the measured bank voltage value of each battery bank, calculating an impedance change amount per time of each battery bank using each of the calculated voltage change amount and the calculated current value, And a controller for analyzing a change pattern of the impedance variation per unit time to determine whether each battery bank is unbalanced. According to the present invention, since a battery bank including battery cells connected in parallel has a similar voltage change pattern at the time of charging and discharging, it determines whether an unbalance situation occurs based on the impedance of the battery bank. Therefore, It is possible to prevent misjudgment.

Description

[0001] APPARATUS AND METHOD FOR DIAGNOSIS OF BATTERY BANK'S IMBALANCING [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for diagnosing an unbalance of a battery bank, and more particularly, to an apparatus and method for diagnosing whether an unbalance occurs in one of battery cells included in a battery bank .

In recent years, due to exhaustion of fossil energy and environmental pollution, there is a growing interest in electric products that can be driven by electric energy without using fossil energy.

Accordingly, as technology development and demand for mobile devices, electric vehicles, hybrid vehicles, power storage devices, uninterruptible power supply devices, and the like are increasing, the demand for secondary batteries as energy sources is rapidly increasing and demand forms are also diversifying. Accordingly, much research has been conducted on secondary batteries to meet various demands.

In general, the secondary battery includes a nickel cadmium battery, a nickel metal hydride battery, a lithium ion battery, and a lithium ion polymer battery. Such a secondary battery is classified into a lithium-based battery and a nickel-hydrogen-based battery. Lithium-based batteries are mainly applied to small-sized products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools and e-bikes. Nickel-hydrogen batteries are used in high- Is being applied to large-sized products which are required.

On the other hand, in order to drive an electric vehicle or a hybrid electric vehicle, an electric motor that requires a high output power must be driven. In the case of power storage devices that supply power to a building or a certain area, it is necessary to supply enough power to meet the power demand. A unit battery cell is manufactured using a secondary battery in order to provide a high output or a large amount of electric power, and a plurality of battery packs made up of the assembled battery cells are connected in series or in parallel to supply a desired output or power.

1 is an exemplary view schematically showing a configuration of a battery pack 10. As shown in Fig.

Referring to FIG. 1, six battery cells 14 are connected in series and in parallel. More specifically, a pair of battery cells 14 are connected in parallel to form one battery bank 11, 12, 13. In this specification, a battery bank is a name for calling a group of battery cells 14 connected in parallel. Three battery banks 11, 12, and 13 are connected in series.

Meanwhile, the voltages of the battery banks 11, 12, and 13 will be denoted as V ₁ , V ₂ , and V ₃ , respectively. By measuring the voltages V ₁ , V ₂ and V ₃ , it is possible to confirm the electrical state such as the amount of charge of each of the battery banks 11, 12 and 13.

However, as shown in the figure, it is assumed that a disconnection occurs in the battery cell 14 included in the lowermost battery bank 13. In the present specification, a case where a problem occurs in the battery cell 14 included in the battery bank 13 will be referred to as 'unbalance'. Thus, since disconnection has occurred in the battery cell 14, the battery bank 12 located at the bottom is in an unbalanced state.

Since the battery cells 14 included in the battery bank 13 are connected in parallel to each other, the voltage of V ₃ will be measured as the voltage of the normally connected battery cell 14. That is, even if an unbalanced situation occurs such as disconnection of the battery cell 14, the voltage of the battery bank 13 may not be affected. Therefore, there arises a problem that it is not possible to detect an unbalanced situation such as disconnection of the battery cell 14 contained in the battery bank 13 only by the voltage V3 of the battery bank 13. [

In order to solve such a problem, various studies have been made on an apparatus and a method that can accurately determine whether a battery cell is imbalanced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and method for accurately diagnosing whether a battery bank is unbalanced.

According to an aspect of the present invention, there is provided an apparatus for diagnosing an unbalance of a battery pack, the battery pack including a plurality of battery banks including battery cells electrically connected in parallel, A current sensor unit for measuring a charging or discharging current of the battery and outputting a current value; A voltage sensor unit for measuring a voltage of each battery bank included in the battery pack and outputting a bank voltage value; And calculating a voltage change amount per time of each battery bank using the measured bank voltage value of each battery bank, calculating an impedance change amount per time of each battery bank using each of the calculated voltage change amount and the calculated current value, And a controller for analyzing a change pattern of the impedance variation per unit time to determine whether each battery bank is unbalanced.

According to an embodiment of the present invention, the controller determines whether the battery bank is unbalanced when all of the measured bank voltage values are higher than a preset reference voltage value.

According to another embodiment of the present invention, when the measured charge or discharge current value of the battery pack is higher than a preset reference current value, the controller determines whether the battery bank is unbalanced.

According to another embodiment of the present invention, when the measured voltage value of all the battery banks is higher than a preset reference voltage value and the measured charging or discharging current value of the battery pack is higher than a preset reference current value It is determined whether or not the battery bank is unbalanced.

According to an embodiment of the present invention, the controller calculates a voltage change amount per time of each battery bank using the measured voltage value of each battery bank, and when a maximum value among the calculated voltage change amounts is less than the calculated voltage change amount And determines whether the battery bank is unbalanced when the minimum value is equal to or greater than the calculated value by multiplying the preset reference value. The preset reference value may be ten.

According to an embodiment of the present invention, when at least one of the calculated variations in impedance of the battery bank per hour is equal to or greater than a predetermined reference impedance variation, the controller determines the battery bank as an unbalanced state.

According to another embodiment of the present invention, when the difference between the maximum value and the minimum value of the calculated variation of the impedance per unit time of each battery bank is equal to or greater than a preset reference impedance variation amount, the controller determines the battery bank as an unbalanced state.

The apparatus for diagnosing an imbalance of a battery bank according to the present invention may further include an alarm unit for visually or audibly outputting an unbalanced state. In this case, the control unit outputs a warning signal to visually or audibly warn that the battery bank is unbalanced through the warning unit when an unbalanced state occurs in any of the battery banks.

The apparatus for diagnosing a battery bank imbalance according to the present invention may further include a memory unit for storing a preset reference counter value. In this case, the control unit increments the counter in the memory unit whenever the battery bank is determined to be in an unbalanced state, and outputs a control signal for stopping the use of the battery pack when the counter reaches the reference counter . The control signal may be a signal for turning off the switch for controlling charging and discharging of the battery pack.

An apparatus for diagnosing a battery bank imbalance according to the present invention includes: a battery bank imbalance diagnosis apparatus; And

And a plurality of battery banks including battery cells electrically connected in parallel to each other. At this time, the plurality of battery banks are electrically connected in series.

A battery pack according to the present invention includes a battery pack; And a load that is supplied with electric power from the battery pack. The load may be an electric drive means or a portable device.

According to another aspect of the present invention, there is provided a method of diagnosing an unbalance of a battery bank in a battery pack in which a plurality of battery banks including electrically connected parallel-connected battery cells are serially connected, a) receiving a charging or discharging current value of the battery pack and a bank voltage value of each battery bank; (b) calculating a voltage change amount per time of each battery bank using the measured voltage value of each battery bank, and calculating an impedance change amount per time of each battery bank using the calculated voltage change amount and the calculated current value; And (c) analyzing a variation pattern of the calculated impedance variation per unit time to determine whether each battery bank is unbalanced.

According to an embodiment of the present invention, the step (b) is a step of calculating a voltage change amount per unit time of each battery bank when the measured voltage value of all the battery banks is higher than a preset reference voltage value.

According to another embodiment of the present invention, the step (b) is a step of calculating a voltage change amount per time of each battery bank when the measured charge or discharge current value of the battery pack is higher than a preset reference current value.

According to another embodiment of the present invention, in the step (b), when the measured voltage value of all the battery banks is higher than a predetermined reference voltage value and the measured charging or discharging current value of the battery pack is greater than a preset reference current value And the voltage change amount per unit time of each battery bank is calculated.

According to another embodiment of the present invention, in the step (b), when the maximum value among the calculated voltage variation amounts is equal to or greater than a value obtained by multiplying the minimum value among the calculated voltage variation amounts by a preset reference value, And calculating the impedance change amount per unit time of each battery bank using the current value. At this time, the preset reference value may be 10.

According to an embodiment of the present invention, the step (c) is a step of determining that the battery bank is in an unbalanced state when the calculated impedance variation per hour of the battery banks is equal to or greater than a preset reference impedance variation.

According to another embodiment of the present invention, in the step (c), when the difference between the maximum value and the minimum value among the calculated variations of the impedance changes per hour of each battery bank is equal to or greater than a preset reference impedance change amount, to be.

The method of diagnosing an unbalance of a battery bank according to the present invention includes the steps of: (d) incrementing a counter every time a battery bank is determined to be in an unbalanced state; And (e) outputting a control signal for stopping the use of the battery pack when the counter reaches a preset reference counter. At this time, the control signal may be a signal for turning off the switch for controlling charging and discharging of the battery pack.

A method for diagnosing an unbalance of a battery bank according to the present invention comprises the steps of: (d) outputting a warning signal to visually or audibly warn that an unbalanced state of a battery bank occurs when an unbalanced state occurs in any of the battery banks; .

According to an aspect of the present invention, it is possible to diagnose whether an unbalanced situation occurs in a battery bank including parallel connected battery cells.

According to another aspect of the present invention, a battery bank including battery cells connected in parallel is similar to a voltage change pattern at the time of charging and discharging, but determines whether an unbalance situation occurs based on the impedance of the battery bank. It is possible to prevent misjudgment depending on only the voltage.

According to another aspect of the present invention, the difference between the maximum value and the minimum value of the voltage change amount can be directly compared, thereby discriminating the measurement error or the impedance difference due to the characteristics of the actual battery cell.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention, And should not be construed as limiting.
1 is an exemplary view schematically showing a configuration of a battery pack.
2 is a block diagram schematically showing the configuration of a battery bank imbalance diagnosis apparatus according to an embodiment of the present invention.
3 to 5 are flowcharts illustrating a method of diagnosing a battery bank imbalance according to an embodiment of the present invention.
6 is a graph of the bank voltage value according to the experimental example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

2 is a block diagram schematically showing the configuration of an apparatus 100 for diagnosing a battery bank imbalance according to an embodiment of the present invention.

Referring to FIG. 2, an apparatus 100 for diagnosing a battery bank imbalance according to the present invention is connected to a battery pack 10 including a plurality of battery cells 14.

The battery pack 10 is composed of six battery cells 14 in total. Two of the six battery cells 14 are connected in parallel. In this specification, a group of battery cells 14 electrically connected in parallel is referred to as a battery bank 11-13. The battery banks 11 to 13 are connected in series to constitute a battery pack 10.

The battery pack 10 shown in Fig. 2 is an exemplary battery pack to which the diagnostic apparatus 100 according to the present invention can be connected. The battery pack 10 includes three battery banks 11 to 13 connected in series and each battery bank 11, 12 and 13 includes two battery cells 14. However, the present invention is not limited by the number of the battery banks 11 to 13 and the number of the battery cells 14. The number of the battery cells 14 included in each of the battery banks 11 to 13 and the number of the battery banks 11 to 13 included in the battery pack 10 are determined by the charge / Voltage, and the like. In addition, each battery cell 14 can be configured in various ways, such as a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel hydride battery, and a nickel zinc battery, which can be recharged and take charge or discharge voltage into consideration.

The diagnostic apparatus 100 according to the present invention includes a current sensor unit 110, a voltage sensor unit 120, and a controller 130.

The current sensor 110 measures a charging or discharging current of the battery pack 10 and outputs a current value to the controller 130. In the present specification, the current value will be denoted by 'I' for convenience of understanding.

2 measures the voltage across the resistor R connected to the low potential terminal of the battery pack 10 to measure the charging and discharging current of the battery pack 10 . However, this is merely an example, and there are various well-known techniques widely known in the art to which the present invention pertains to the method of measuring the charging and discharging current of the battery pack 10. [ Therefore, the present invention is not limited to the embodiment of the current sensor unit 110 shown in FIG.

The voltage sensor unit 120 measures the voltage of each of the battery banks 11 to 13 included in the battery pack 10 and outputs the voltage to the controller 130. In this specification, a voltage value output from the voltage sensor unit 120 is referred to as a 'bank voltage value'. For convenience of understanding, the bank voltage value corresponding to the battery bank 11 located at the top of the drawing will be denoted by 'V1'. Similarly, the bank voltage value corresponding to the battery bank 12 located at the center of the drawing will be denoted by 'V2'. Finally, the bank voltage value corresponding to the battery bank 13 located at the bottom of the drawing will be denoted by " V3 ". The specific configuration and operation principle of the voltage sensing unit 120 are well known in the technical field of the present invention, and a detailed description thereof will be omitted.

The current sensing unit 110 and the voltage sensing unit 120 may measure the current value and the bank voltage values V1 to V3 in real time and output the current value and the bank voltage values V1 to V3 to the controller 130. [ The current sensing unit 110 and the voltage sensing unit 120 may measure the current value and the bank voltage values V1 to V3 according to a predetermined period and output the current value and the bank voltage values V1 to V3 to the controller 130. The predetermined period may be variously set.

The diagnostic apparatus 100 according to the present invention may further include a memory unit 140. [ The memory unit 140 may be located inside or outside the control unit 130 and may be connected to the control unit 130 by various well-known means. The memory unit 140 is a mass storage medium such as a known semiconductor device or a hard disk that is known to record and erase data such as RAM, ROM, and EEPROM, and refers to a device that stores information regardless of the type of device And does not refer to a specific memory device.

The controller 130 stores the bank voltage values V1 to V3 and the current value I in the memory unit 140. [

The controller 130 calculates a voltage change amount per unit time of each battery bank using the bank voltage values V1 to V3. In the present specification, the voltage change amount per unit time of the bank voltage value 'V1' will be denoted by 'ΔV1'. Similarly, the voltage change amount per unit time of the bank voltage value 'V2' is denoted by '? V2' and the voltage change amount per unit time of the bank voltage value 'V3' is denoted by? V3 '. The controller 130 stores the ΔV1, ΔV2, and ΔV3 in the memory unit 140.

Further, the control unit 130 calculates the amount of change in impedance per unit time of each battery bank using the change amount (? V1 to? V3) of each bank voltage value and the current value (I). Impedance can be easily calculated by anyone having ordinary skill in the art to which the present invention belongs, and detailed description of the calculation formula will be omitted.

For ease of understanding, the impedance change amount of the battery bank 11 located at the uppermost position in the drawing will be denoted by '? Z1' in the present specification. Similarly, the impedance change amount of the battery bank 12 located at the center of the drawing will be denoted by '? Z2'. Finally, the amount of change in impedance of the battery bank 13 located at the bottom of the drawing will be denoted by '? Z3'.

The controller 130 analyzes the calculated change pattern of the impedance change amounts? Z1,? Z2,? Z3 per unit time to determine whether the battery banks 11, 12, 13 are unbalanced. An algorithm for determining the unbalance of the controller 130 will be described in detail below.

In this specification, an unbalance means a problem occurring between the battery cells 14 included in the battery banks 11 to 13. As described briefly above, the situation such as disconnection of the battery cell 14 included in the battery bank 13 is also unbalanced. Also, a difference in the amount of charge between the battery cells 14 included in the battery banks 11, 12, and 13 is also unbalanced. It is also unbalanced when a difference in internal resistance value occurs due to various causes such as degradation between the battery cells 14 included in the battery banks 11, 12, and 13. That is, the imbalance means a case where there is a difference in performance, charging amount, connection state, etc. between the battery cells 14 included in each battery bank 11, 12, 13.

The diagnostic apparatus 100 according to the present invention may further include a warning unit 150 for visually or auditorily outputting an unbalanced state. In this case, when an unbalanced state occurs in at least one of the battery banks 11 to 13 included in the battery pack 10, the control unit 130 determines that an unbalance has occurred through the warning unit 150 A warning signal can be output to warn the user visually or audibly.

For example, the alarm unit 150 may include an LED, an LCD, an alarm, or a combination thereof. In this case, the warning unit 150 may flash an LED, output a warning message to the LCD, or generate an alarm or a buzzer sound to warn the user of the occurrence of an unbalanced condition. However, the present invention is not limited thereto. In addition, the LED, LCD, and alarm alarm are only examples of the alarm unit 150, and various modified forms of the visual or auditory alarm device can be employed as the alarm unit 150, And will be apparent to those skilled in the art.

The control unit 130 may output a control signal for stopping the use of the battery pack 10 when determining that at least one of the battery banks 11, 12 and 13 is in an unbalanced state. At this time, the control signal may be a signal for turning off the switch 160 for controlling the charging and discharging of the battery pack 10.

The controller 130 may be implemented as a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a microprocessor, etc., as is known in the art to perform the calculation and various control logic, A data processing device, and the like. In addition, when the control logic described below is implemented in software, the control unit 130 may be implemented as a set of program modules. At this time, the program module is stored in the memory unit 130 and can be executed by the processor.

Hereinafter, a method for diagnosing a battery bank imbalance according to an embodiment of the present invention will be described. However, the configuration and the overlapping description of the diagnostic apparatus 100 described above will be omitted.

3 to 5 are flowcharts illustrating a method of diagnosing a battery bank imbalance according to an embodiment of the present invention.

First, in step 200, the controller 130 supplies a predetermined reference voltage value Vref, a reference current value Iref, a reference value K, a reference impedance change amount Zref, or a reference counter value Nref to the memory unit 140 ). The values may be stored in the memory unit 140 and only some of the values may be stored in the memory unit 140 according to an embodiment of the present invention. The role of these values will be described in detail according to various embodiments below. The control unit 130 ends the process of step 200 and proceeds to step 201. [

In step 201, the controller 130 receives the current value I from the current sensing unit 110 and stores the current value I in the memory unit 140. The control unit 130 ends the process of step 201 and proceeds to step 202. [

In step 202, the controller 130 receives the bank voltage values V1 to V3 and stores the received bank voltage values in the memory unit 140. [ The control unit 130 ends the process of step 202 and proceeds to step 203. [

According to an embodiment of the present invention, the control unit 130 determines whether the battery bank is unbalanced when the measured bank voltage values V1 to V3 are all higher than a preset reference voltage value Vref. The impedance change patterns? Z1,? Z2,? Z3 of the battery banks 11 to 13 become more clear as the output voltages V1 to V3 of the battery banks 11 to 13 become higher.

Accordingly, in step 203, the controller 130 determines whether all of the measured bank voltage values V1 to V3 are higher than a predetermined reference voltage value Vref.

If at least one of the respective bank voltage values V1 to V3 is lower than a preset reference voltage value Vref (NO in step 203), the controller 130 is not suitable for diagnosing whether or not the battery bank is unbalanced . Thus, the control unit 130 ends the process.

On the other hand, if all of the bank voltage values V1 to V3 are all higher than the preset reference voltage value Vref (YES in step 203), the controller 130 determines that the battery bank is unbalanced. The control unit 130 ends the process of step 203 and proceeds to step 204. [

The control unit 130 determines whether the battery bank 10 is unbalanced when the measured current value I of the battery pack 10 is higher than a predetermined reference current value Iref. As the current value I of the battery pack 10 is higher, the impedance change patterns? Z1,? Z2,? Z3 of the battery banks 11 to 13 become more clear.

Accordingly, in step 204, the controller 130 determines whether the measured current value I is higher than a preset reference current value Iref.

If the current value I is lower than the preset reference current value Iref (NO in step 204), the controller 130 determines that it is not suitable to diagnose whether or not the battery bank is unbalanced. Thus, the control unit 130 ends the process.

On the other hand, if the current value I is higher than the preset reference current value Iref (YES in step 203), the control unit 130 determines that it is appropriate to diagnose whether or not the battery bank is unbalanced. The control unit 130 ends the process of step 204 and proceeds to step 205. [

The order of performing the algorithm may be changed in the steps 203 and 204. Also, according to the embodiment, the controller 130 may perform only one of the steps 203 and 204.

According to an embodiment of the present invention, when the voltage values (V1 to V3) of each of the measured battery banks are both higher than a preset reference voltage value (Vref) and the charging or discharging of the measured battery pack It is determined whether the battery bank is unbalanced only when the discharge current value I is higher than a preset reference current value Iref. In this case, the method for diagnosing an unbalance of the battery bank according to the present invention includes both steps 203 and 204 described above.

In step 205, the controller 130 calculates the voltage change amounts? V1,? V2, and? V3 per unit time of each battery bank using the bank voltage values (V1 to V3) of each battery bank. The interval for calculating the voltage change amounts (? V1,? V2,? V3) may be set to various values such as 1 second, 3 seconds, 5 seconds, and 10 seconds. The control unit 130 ends the process of step 205 and proceeds to step 206. [

In step 206, the controller 130 stores the voltage change amounts? V1,? V2, and? V3 per unit time of the battery bank in the memory unit 140. The control unit 130 ends the process of step 206 and proceeds to step 207. [

According to an embodiment of the present invention, when the maximum value among the calculated voltage variation amounts is equal to or greater than a value obtained by multiplying a minimum value among the calculated voltage variation amounts by a preset reference value K, It is judged whether or not there is an imbalance.

In step 207, the controller 130 distinguishes the minimum value? Vmin and the maximum value? Vmax among the calculated voltage variation amounts. The control unit 130 ends the process of step 207 and proceeds to step 208. [

In step 208, the controller 130 multiplies the minimum value? Vmin among the calculated voltage variation amounts by the reference value K. The reference value K may be variously set. For example, the reference value K may be 10. The controller 130 determines whether the maximum value? Vmax is greater than the calculated value by multiplying the minimum value? Vmin by the reference value K. In step 208, it can be determined whether the change pattern of the maximum value? Vmax among the voltage change amounts is much larger than the voltage change amounts of the other battery banks. This is because it is presumed that an unbalanced state of the battery bank occurs because the voltage change amount is much larger than the voltage change amount of the other battery banks.

If 'NO' in step 208, the controller 130 determines that it is not suitable to diagnose whether the battery bank is unbalanced. That is, the controller 130 can determine that the difference in the voltage variation amount is within a measurement error range, or may be a difference in degree that can occur depending on the characteristics of the actual battery cell. Thus, the control unit 130 ends the process.

If " YES " in step 208, the control unit 130 ends the process of step 208 and proceeds to step 209. [

The steps 207 and 208 may not be necessary according to the embodiment of the method for diagnosing a battery bank imbalance according to the present invention. Therefore, according to another embodiment of the present invention, the controller 130 may complete the process of step 206 and proceed to step 209. [

In step 209, the controller 130 calculates the impedance change amounts DELTA Z1, DELTA Z2, and DELTA Z3 per unit time of each battery bank using the respective voltage change amounts DELTA V1, DELTA V2, DELTA V3 and the current value I. The controller 130 stores the calculated impedance change amounts? Z1,? Z2, and? Z3 of each battery bank in the memory unit 140. The control unit 130 ends the process of step 209 and proceeds to step 210. [

In step 210, the controller 130 determines whether an unbalance has occurred in the battery bank included in the battery pack 10.

According to an embodiment of the present invention, when any one of the calculated impedance variation amounts? Z1,? Z2,? Z3 of each battery bank calculated is equal to or greater than a predetermined reference impedance variation amount? Zref, It is judged to be in an unbalanced state.

According to another embodiment of the present invention, the controller 130 determines a maximum value? Zmax and a minimum value? Zmin among the calculated impedance change amounts? Z1,? Z2,? Z3 of each battery bank. If the difference between the maximum value DELTA Zmax and the minimum value DELTA Zmin is equal to or greater than a predetermined reference impedance change DELTA Zref, the battery bank is determined to be in an unbalanced state.

If the control unit 130 determines that an unbalance has not occurred (NO in step 210), the control unit 130 ends the process. On the other hand, if the control unit determines that an imbalance has occurred (YES in step 210), the process proceeds to step 211 or step 212.

According to an embodiment of the present invention, the controller 130 proceeds to step 211. [ In step 211, the control unit 130 outputs a warning signal through the warning unit 150 so as to warn the occurrence of an unbalanced state of the battery bank visually or audibly.

According to another embodiment of the present invention, the controller 130 proceeds to step 212. In step 212, the controller 130 increments the counter N in the memory unit 130 whenever it determines that any one of the battery banks is in an unbalanced state. In step 213, the control unit 130 determines whether the reference counter value Nref matches the preset reference counter value Nref in the memory unit 140. If it does not match (NO in step 213), the control unit 130 moves the processor to step 201. [ Therefore, it is repeatedly performed whether or not the imbalance of the battery bank in steps 201 to 210 occurs. At this time, if the counter N is incremented in the memory unit 130 and coincides with the preset reference counter value Nref (YES in step 213), the control unit 130 moves the processor to step 214 . In step 214, the controller 130 outputs a control signal for stopping the use of the battery pack 10. At this time, the control signal may be a signal for turning off the switch for controlling charging and discharging of the battery pack. The present embodiment can more accurately determine whether a battery bank is unbalanced through a repetitive diagnosis process.

The diagnostic apparatus 100 according to the present invention can be a component of a battery pack including a plurality of battery banks including battery bank imbalance diagnosis apparatus and electrically parallel connected battery cells. At this time, the plurality of battery banks are electrically connected in series.

The battery pack according to the present invention may be a component of the battery driving system including the battery pack and a load supplied with power from the battery pack.

Examples of the battery driving system include an electric vehicle (EV), a hybrid vehicle (HEV), an electric bicycle (E-Bike), a power tool, an energy storage system, an uninterruptible power supply (UPS) A battery pack, a portable computer, a portable telephone, a portable audio device, a portable video device, and the like. An example of the load is a power supplied from a motor or a battery pack, And may be a power conversion circuit for converting the power into a required power.

According to the present invention, it is possible to diagnose whether an unbalanced situation occurs in a battery bank including battery cells connected in parallel. In addition, since the battery bank including the battery cells connected in parallel has a similar voltage change pattern at the time of charging and discharging, it is determined whether or not an unbalance situation occurs based on the impedance of the battery bank. Can be prevented. On the other hand, the difference between the maximum value and the minimum value of the voltage change amount can be directly compared to discriminate the measurement error or the impedance difference due to the characteristics of the actual battery cell.

In the meantime, in describing the present invention, each configuration of the diagnostic apparatus 100 according to the present invention shown in FIG. 2 should be understood as a logical component rather than a physically separated component.

That is, since each configuration corresponds to a logical component for realizing the technical idea of the present invention, even if each component is integrated or separated, if the functions performed by the logical configuration of the present invention can be realized, And it is to be understood that any component that performs the same or similar function should be construed as being within the scope of the present invention irrespective of the consistency of the name.

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 to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

<Experimental Example>

Experimental examples will be presented for convenience of understanding the present invention.

As shown in FIG. 2, six battery cells 14 constitute two battery banks 11 to 13, and three battery banks 11 to 13 are connected in series. Respectively.

6 is a graph of the bank voltage value according to the experimental example.

Referring to FIG. 6, the bank voltage values (V1, V2, and V3) for the first battery banks 11 to 13 can be confirmed. The battery cells 14 included in the battery pack 10 used in this experiment are fully charged. The buffered display voltage of the battery cell 14 is 4170 mV.

In this experiment, the discharge did not start in the interval from 1 second to 121 seconds. Then, at 121 seconds, the battery pack 10 started to discharge a current of 1000 mA.

It can be seen that the bank voltage values (V1, V2, V3) drop rapidly at 121 seconds. This is because the bank voltage values (V1, V2, V3) are lowered by the load drop (IR drop) while the battery pack 10 starts discharging. However, in this case, the voltage change amounts? V1 to? V3 all have a large value, but the difference between the maximum voltage change amount? Vmax and the minimum value? Vmin among the voltage change amounts? V1 to? V3 is insignificant. Therefore, the diagnostic apparatus 100 according to the present invention does not calculate the impedance.

It can be confirmed that the respective bank voltage values (V1, V2, V3) are gradually lowered due to the discharge of the battery pack 10 in the interval of 121 seconds to 241 seconds. Therefore, the difference between the maximum voltage change amount? Vmax and the minimum value? Vmin among the voltage change amounts? V1 to? V3 during 121 seconds to 241 seconds is insufficient. Therefore, the diagnostic apparatus 100 according to the present invention does not calculate the impedance.

There was a situation where any one of the battery cells 14 included in the battery bank 13 located at the lowermost position was disconnected due to an impact from the outside of the battery pack 10 in 241 seconds. That is, the battery bank 13 has an unbalanced state.

Therefore, the bank voltage value V3 has dropped abruptly, whereby the voltage change amount? V3 has a value of 100 mV. At this time, the maximum voltage change amount? Vmax is 100 mV as? V3, and the minimum value? Vmin is 1 mV as? V1. That is, the difference between the maximum voltage change amount? Vmax and the minimum voltage change amount? Vmin is about 100 times different. Therefore, the diagnostic apparatus 100 according to the present invention starts calculating the impedance.

The impedance change amount? Z3 of the battery bank V3 is 0.1?. It can be confirmed that the impedance change amount? Z1 of the battery bank V1 is a large change as compared with 0.001?. Accordingly, the diagnostic apparatus 100 according to the present invention determines that an unbalanced condition occurs in the battery bank V3.

10: Battery pack 11 to 13: Battery bank
14: Battery cell 100: Unbalance diagnosis device of battery bank
110: current sensor unit 120: voltage sensor unit
130: control unit 140: memory unit
150: warning section 160: switch section

Claims (25)

delete delete delete An apparatus for diagnosing an unbalance of a battery pack electrically connected in series with a plurality of battery banks including battery cells electrically connected in parallel,
A current sensor unit for measuring a charging or discharging current of the battery pack and outputting a measured current value to a control unit;
A voltage sensor unit for measuring a voltage of each battery bank included in the battery pack and outputting the measured bank voltage value to the control unit; And
Calculating a variation in voltage per unit time of each battery bank using the measured bank voltage value of each battery bank, calculating a variation in impedance per unit time of each battery bank using the calculated voltage variation amount and the calculated current value, And a controller for determining whether each battery bank is unbalanced using an impedance change amount,
The control unit may determine whether the battery bank is unbalanced when the measured voltage value of all the battery banks is higher than a preset reference voltage value and the measured charging or discharging current value of the battery pack is higher than a preset reference current value And a battery bank unbalance diagnosis device. delete delete An apparatus for diagnosing an unbalance of a battery pack electrically connected in series with a plurality of battery banks including battery cells electrically connected in parallel,
A current sensor unit for measuring a charging or discharging current of the battery pack and outputting a measured current value to a control unit;
A voltage sensor unit for measuring a voltage of each battery bank included in the battery pack and outputting the measured bank voltage value to the control unit; And
Calculating a variation in voltage per unit time of each battery bank using the measured bank voltage value of each battery bank, calculating a variation in impedance per unit time of each battery bank using the calculated voltage variation amount and the calculated current value, And a controller for determining whether each battery bank is unbalanced using an impedance change amount,
Wherein the controller determines that the battery bank is in an unbalanced state when any one or more of the calculated impedance variation amounts per unit time of the battery bank is equal to or greater than a preset reference impedance variation amount. An apparatus for diagnosing an unbalance of a battery pack electrically connected in series with a plurality of battery banks including battery cells electrically connected in parallel,
A current sensor unit for measuring a charging or discharging current of the battery pack and outputting a measured current value to a control unit;
A voltage sensor unit for measuring a voltage of each battery bank included in the battery pack and outputting the measured bank voltage value to the control unit; And
Calculating a variation in voltage per unit time of each battery bank using the measured bank voltage value of each battery bank, calculating a variation in impedance per unit time of each battery bank using the calculated voltage variation amount and the calculated current value, And a controller for determining whether each battery bank is unbalanced using an impedance change amount,
Wherein the controller determines that the battery bank is in an unbalanced state when the difference between the maximum value and the minimum value of the calculated impedance variation amount of each battery bank per hour is equal to or greater than a preset reference impedance variation amount. delete An apparatus for diagnosing an unbalance of a battery pack electrically connected in series with a plurality of battery banks including battery cells electrically connected in parallel,
A current sensor unit for measuring a charging or discharging current of the battery pack and outputting a measured current value to a control unit;
A voltage sensor unit for measuring a voltage of each battery bank included in the battery pack and outputting the measured bank voltage value to the control unit;
Calculating a variation in voltage per unit time of each battery bank using the measured bank voltage value of each battery bank, calculating a variation in impedance per unit time of each battery bank using the calculated voltage variation amount and the calculated current value, A controller for determining whether each battery bank is unbalanced using an impedance change amount; And
And a memory unit for storing a preset reference counter value,
The control unit increases the counter in the memory unit whenever the battery bank is determined to be in an unbalanced state and outputs a control signal for stopping the use of the battery pack when the counter reaches the reference counter And a battery bank unbalance diagnosis device. 11. The method of claim 10,
Wherein the control signal is a signal for turning off a switch for controlling charging and discharging of the battery pack. An apparatus for diagnosing a battery bank imbalance according to any one of claims 4, 7, 8, 10, and 11; And
A plurality of battery banks including battery cells electrically connected in parallel,
Wherein the plurality of battery banks are electrically connected in series. The battery pack according to claim 12,
And a load supplied with power from the battery pack. 14. The method of claim 13,
Wherein the load is an electric drive means or a portable device. delete delete delete A method for diagnosing whether a battery bank is unbalanced in a battery pack in which a plurality of battery banks including electrically parallel-connected battery cells are electrically connected in series,
(a) receiving a charging or discharging current value of the battery pack and a bank voltage value of each battery bank;
(b) calculating a voltage change amount per time of each battery bank using the measured voltage value of each battery bank, calculating an impedance change amount per time of each battery bank using each of the calculated voltage change amount and the calculated current value; And
(c) judging whether or not each battery bank is unbalanced using the calculated change in impedance per unit time,
The method of claim 1, wherein the step (b) comprises: if a voltage value of all the measured battery banks is higher than a preset reference voltage value and a measured charging or discharging current value of the battery pack is higher than a preset reference current value, And calculating a variation amount of the battery bank. delete delete A method for diagnosing whether a battery bank is unbalanced in a battery pack in which a plurality of battery banks including electrically parallel-connected battery cells are electrically connected in series,
(a) receiving a charging or discharging current value of the battery pack and a bank voltage value of each battery bank;
(b) calculating a voltage change amount per time of each battery bank using the measured voltage value of each battery bank, calculating an impedance change amount per time of each battery bank using each of the calculated voltage change amount and the calculated current value; And
(c) judging whether or not each battery bank is unbalanced using the calculated change in impedance per unit time,
Wherein the step (c) includes the step of determining that the battery bank is in an unbalanced state when the calculated impedance change amount per hour of the battery bank is equal to or greater than a predetermined reference impedance change amount. A method for diagnosing whether a battery bank is unbalanced in a battery pack in which a plurality of battery banks including electrically parallel-connected battery cells are electrically connected in series,
(a) receiving a charging or discharging current value of the battery pack and a bank voltage value of each battery bank;
(b) calculating a voltage change amount per time of each battery bank using the measured voltage value of each battery bank, calculating an impedance change amount per time of each battery bank using each of the calculated voltage change amount and the calculated current value; And
(c) judging whether or not each battery bank is unbalanced using the calculated change in impedance per unit time,
Wherein the step (c) includes the step of determining that the battery bank is in an unbalanced state when a difference between a maximum value and a minimum value of the calculated impedance variation amount per each battery bank is equal to or greater than a preset reference impedance variation amount Asymmetry diagnosis method. A method for diagnosing whether a battery bank is unbalanced in a battery pack in which a plurality of battery banks including electrically parallel-connected battery cells are electrically connected in series,
(a) receiving a charging or discharging current value of the battery pack and a bank voltage value of each battery bank;
(b) calculating a voltage change amount per time of each battery bank using the measured voltage value of each battery bank, calculating an impedance change amount per time of each battery bank using each of the calculated voltage change amount and the calculated current value;
(c) determining whether each battery bank is unbalanced using the calculated change in impedance per unit time;
(d) incrementing the counter each time one of the battery banks is determined to be in an unbalanced state; And
(e) outputting a control signal for stopping the use of the battery pack when the counter reaches a preset reference counter. 24. The method of claim 23,
Wherein the control signal is a signal for turning off a switch for controlling charging and discharging of the battery pack. delete

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