阅读说明：本技术 电池诊断装置和方法 (Battery diagnosis device and method ) 是由 李铉澈 权洞槿 尹成烈 金承显 金安洙 于 2020-07-23 设计创作，主要内容包括：根据本发明的实施例的电池诊断装置可以包括：电压测量单元,该电压测量单元用于在预设时间段期间测量每个电池单体的电压；电压变化计算单元,该电压变化计算单元用于在预设时间段期间计算每个电池单体的单独电压变化；平均电压变化计算单元,该平均电压变化计算单元用于在预设时间段期间计算多个电池单体的平均电压变化；以及异常检测单元,该异常检测单元用于当存在单独电压变化与平均电压变化之间的差大于阈值的电池单体时,确定在对应电池单体中已经发生电压异常。(The battery diagnosis apparatus according to an embodiment of the present invention may include: a voltage measuring unit for measuring a voltage of each battery cell during a preset time period; a voltage variation calculation unit for calculating an individual voltage variation of each battery cell during a preset time period; an average voltage variation calculation unit for calculating an average voltage variation of the plurality of battery cells during a preset time period; and an abnormality detection unit for determining that a voltage abnormality has occurred in the corresponding battery cell when there is a battery cell whose difference between the individual voltage variation and the average voltage variation is greater than a threshold value.)

1. A battery diagnostic device comprising:

a voltage measuring unit for measuring a voltage of each battery cell during a preset time period;

a voltage variation calculation unit for calculating an individual voltage variation of each battery cell during the preset time period;

an average voltage variation calculation unit for calculating an average voltage variation of the plurality of battery cells during the preset time period; and

an abnormality detection unit for determining that a voltage abnormality has occurred in a corresponding battery cell when there is a battery cell whose difference between the individual voltage variation and the average voltage variation is greater than a threshold value.

2. The battery diagnostic apparatus according to claim 1, further comprising a storage unit for storing the individual voltage variation of each battery cell and the average voltage variation of the plurality of battery cells.

3. The battery diagnosis device according to claim 1, wherein the voltage change calculation unit calculates a voltage change of each battery cell during charging or discharging of the battery cells.

4. The battery diagnosis device according to claim 1, wherein the voltage change calculation unit calculates the voltage change of the battery cell in a stationary state in which no current flows in the battery cell.

5. The battery diagnostic device according to claim 1, wherein the threshold value is set according to manufacturer-specific specifications of the battery cell.

6. The battery diagnostic device according to claim 1, wherein the threshold value is set according to a manufacturer-specific specification of the voltage measurement unit.

7. The battery diagnostic device according to claim 1, wherein the threshold value is 15 mV.

8. The battery diagnosis device according to claim 1, wherein the voltage variation calculation unit calculates the voltage variation of each battery cell in an interval in which a state of charge (SOC) of the battery cell is equal to or greater than a preset reference value.

9. The battery diagnosis device according to claim 1, wherein the preset reference value is set according to a type of the battery cell.

10. A battery diagnostic method comprising:

measuring a voltage of each battery cell during a preset time period;

calculating an individual voltage change of each battery cell during the preset time period;

calculating an average voltage variation of a plurality of battery cells during the preset time period; and

determining that a voltage abnormality has occurred in the corresponding battery cell when a difference between the individual voltage variation and the average voltage variation is greater than a threshold value.

Technical Field

The present invention relates to a battery diagnosis apparatus and method, and more particularly, to a battery diagnosis apparatus and method for detecting a sudden drop in voltage during charging and discharging of a battery.

Background

Recently, research and development of secondary batteries have been actively conducted. Here, the secondary battery is a battery that can be charged/discharged, and includes all of typical Ni/Cd batteries, Ni/MH batteries, and the like, and recently lithium ion batteries. The lithium ion battery among the secondary batteries has an advantage in that its energy density is much higher than that of a typical Ni/Cd battery, Ni/MH battery, or the like. Also, the lithium ion battery can be made small and light, and thus is used as a power source for mobile devices. In addition, lithium ion batteries have been spotlighted as next-generation energy storage media because their use range has been expanded to power sources of electric vehicles.

In addition, the secondary battery is generally used as a battery pack including a battery module in which a plurality of battery cells are connected in series and/or parallel. In addition, the state and operation of the battery pack are managed and controlled by a battery management system.

If an abnormality such as an insulation error of the battery pack or an internal short circuit of the battery cell itself occurs, the battery cell voltage of the battery module may suddenly drop. At this time, generally, a method of performing diagnosis by detecting whether there is a voltage drop using a voltage difference (slope) from a previous time in a state where no current flows (stationary) has been used, and therefore, it is absolutely necessary to determine the state where no current flows using a separate current sensor.

Disclosure of Invention

[ problem ] to

An aspect of the present invention provides a battery diagnosis device capable of diagnosing a voltage abnormality of a battery cell by using a voltage variation of the battery cell without a separate current sensor, thereby detecting an abnormality due to an abrupt voltage drop of the battery cell not only in a state where the voltage of the battery does not flow (is stationary), but also during charge and discharge of the battery.

[ solution ]

According to an aspect of the present invention, there is provided a battery diagnosis apparatus including: a voltage measuring unit for measuring a voltage of each battery cell during a preset time period; a voltage variation calculation unit for calculating an individual voltage variation of each battery cell during a preset time period; an average voltage variation calculation unit for calculating an average voltage variation of the plurality of battery cells during a preset time period; and an abnormality detection unit for determining that a voltage abnormality has occurred in the corresponding battery cell when there is a battery cell whose difference between the individual voltage variation and the average voltage variation is greater than a threshold value.

The voltage variation calculation unit of the battery diagnosis device according to the embodiment of the present invention may calculate the voltage variation of each battery cell during the charge or discharge of the battery cell.

The voltage change calculation unit of the battery diagnosis device according to the embodiment of the present invention may calculate the voltage change of the battery cell in a state where no current flows (is stationary) in the battery cell.

The threshold value of the battery diagnosis apparatus according to the embodiment of the present invention may be set according to manufacturer-specific specifications of the battery cell.

The threshold value of the battery diagnosis apparatus according to the embodiment of the present invention may be set according to the manufacturer-specific specification of the voltage measurement unit.

The voltage variation calculation unit of the battery diagnosis device according to the embodiment of the present invention may calculate the voltage variation of each battery cell in an interval in which a state of charge (SOC) of the battery cell is equal to or greater than a preset reference value.

The preset reference value of the battery diagnosis apparatus according to the embodiment of the present invention may be set according to the type of the battery cell.

According to another aspect of the present invention, there is provided a battery diagnosis method including: measuring a voltage of each battery cell during a preset time period; calculating an individual voltage change of each battery cell during a preset time period; calculating an average voltage variation of the plurality of battery cells during a preset time period; and determining that a voltage abnormality has occurred in the corresponding battery cell when there is a battery cell whose difference between the individual voltage variation and the average voltage variation is greater than a threshold value.

[ Effect of the invention ]

According to the battery diagnosis device of the present invention, the voltage abnormality of the battery cell is diagnosed by using the voltage variation of the battery cell without a separate current sensor. Therefore, it is possible to detect an abnormality due to an abrupt voltage drop of the battery not only during the charge and discharge of the battery but also in a stationary state in which the voltage of the battery does not flow.

Drawings

Fig. 1 is a block diagram showing a typical configuration of a battery control system;

fig. 2 is a block diagram showing a configuration of a battery diagnosis apparatus according to an embodiment of the present invention;

fig. 3 is a view illustrating a diagnostic experiment performed on a defective cell by the battery diagnosis apparatus according to the embodiment of the present invention when the battery is charged;

fig. 4 is a view illustrating a diagnostic experiment performed on a defective cell by the battery diagnostic apparatus according to the embodiment of the present invention when the battery is in a stationary state;

fig. 5 is a flowchart illustrating a battery diagnosis method according to an embodiment of the present invention; and

fig. 6 is a view showing a configuration of hardware according to an embodiment of the present invention.

Detailed Description

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. Herein, the same reference numerals are used for the same elements throughout the drawings, and redundant description of the same elements is omitted.

The specific structure described as a function of the various embodiments of the invention disclosed herein is merely illustrative of the invention. Various embodiments of the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein.

Terms such as "a first," "a second," "a first," and "a second," used in various embodiments, may modify various components without regard to their order and/or importance and do not limit corresponding components. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of other embodiments. Unless the context clearly dictates otherwise, singular expressions may include plural expressions.

All terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms defined in commonly used dictionaries should be interpreted as having the same or similar meaning as the meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some cases, even the terms defined herein should not be construed as excluding embodiments of the invention.

Fig. 1 is a block diagram showing a typical configuration of a battery control system.

Specifically, fig. 1 is a configuration diagram schematically showing a battery control system including a battery pack 1 according to an embodiment of the present invention and a superior controller 2 included in a superior system.

As shown in fig. 1, the battery pack 1 is constituted by one or more battery cells, and includes: a battery module 10 that is chargeable and dischargeable; a switching unit 14 connected in series to the + terminal side or the-terminal side of the battery module 10 to control the charge/discharge current of the battery module 10; and a Battery Management System (BMS)20 for controlling and managing to prevent overcharge, overdischarge, etc. by monitoring the voltage, current, temperature, etc. of the battery pack 1.

Here, the switching unit 14 is a semiconductor switching element for controlling a current for charging or discharging the battery module 10, and for example, at least one MOSFET may be used.

In addition, the BMS 20 may measure or calculate the voltage and current of the gate, source, drain, etc. of the semiconductor switching element in order to monitor the voltage, current, temperature, etc. of the battery pack 1. In addition, the voltage, current, temperature, etc. of the battery pack 1 may be measured using the sensor 12 disposed adjacent to the semiconductor switching element 14. The BMS 20 is an interface that receives input measured values of the above-described various parameters, and may include a plurality of terminals, a circuit connected to the terminals to process the input values, and the like.

In addition, the BMS 20 may control on/off of the switching element 14 (e.g., MOSFET) and may be connected to the battery module 10 to monitor the state of the battery module 10.

The upper level controller 2 may transmit a control signal for the battery module 10 to the BMS 20. Accordingly, the operation of the BMS 20 may be controlled based on the signal applied from the upper controller 2. The battery cell of the present invention may be a component included in a battery pack used in an Energy Storage System (ESS), a vehicle, or the like. However, the battery cell is not limited to such use.

The configuration of the battery pack 1 and the configuration of the BMS 20 described above are known in the art, and thus, a detailed description thereof will be omitted.

Fig. 2 is a block diagram showing the configuration of a battery diagnosis apparatus according to an embodiment of the present invention.

Referring to fig. 2, the battery diagnosis apparatus 200 according to the embodiment of the present invention may include a voltage measurement unit 210, a voltage variation calculation unit 220, an average voltage variation calculation unit 230, and an abnormality detection unit 240.

The voltage measuring unit 210 may measure the voltage of each battery cell during a preset time period. For example, the voltage measuring unit 210 may be a measuring circuit included in the above-described battery management system BMS.

The voltage variation calculation unit 220 may calculate an individual voltage variation of each battery cell measured by the voltage measurement unit 210 during a preset time period. For example, when the voltages of the battery cells are measured at intervals of 2 seconds in the voltage measuring unit 210, the voltage variation calculating unit 220 may calculate individual voltage variations of each battery cell for two seconds. However, this is merely exemplary. The time interval may be arbitrarily set by the user.

In particular, the voltage change calculation unit 220 may calculate the voltage change of each battery cell not only in a state where no current flows in the battery cell (stationary) but also during the charge or discharge of the battery cell. Therefore, in general, a current sensor is absolutely required to confirm the stationary state of the battery. However, the battery diagnosis apparatus 200 according to the embodiment of the present invention may detect a sudden voltage drop only by using a battery voltage change without having to determine the stationary state of the battery through a current sensor.

In addition, the voltage variation calculation unit 220 may calculate a voltage variation of each battery cell for a section in which a state of charge (SOC) of the battery cell is equal to or greater than a preset reference value. This is because the resistance of the battery itself increases in the section where the SOC of the battery is low, so that the deviation of the Direct Current Internal Resistance (DCIR) may increase. At this time, the reference value of the SOC may be set according to the type of the battery cell.

The average voltage variation calculation unit 230 may calculate an average voltage variation of the plurality of battery cells during a preset time period. For example, the average voltage variation calculation unit 230 may calculate the average voltage variation of all the battery cells included in a specific battery pack during a preset time period.

When there is a battery cell in which the difference between the individual voltage variation calculated in the voltage variation calculation unit 220 and the average voltage variation calculated in the average voltage variation calculation unit 230 is greater than the threshold value, the abnormality detection unit 240 may determine that a voltage abnormality has occurred in the corresponding battery cell.

That is, the abnormality detecting unit 240 may detect the voltage abnormality of the battery according to the following equation.

[ equation 1]

ΔV_{Monomers each of}-ΔV_{Monomer, average}＝V_{Threshold value}

At this time, the current SOC value>SOC_{Threshold value}

In this case, the threshold value of the abnormality detection unit 240 may be set according to manufacturer-specific specifications of the battery cell and the voltage measurement unit 210. For example, the threshold value may be set in consideration of a voltage measurement error of the voltage measurement unit 210, a capacity error between the battery cells generated during the assembly of the battery module, and the like.

Meanwhile, although not shown in fig. 2, the battery diagnosis device 200 according to an embodiment of the present invention may further include a storage unit (not shown) for storing individual voltage variation of each battery cell and average voltage variation of a plurality of battery cells.

As described above, the battery diagnosis device according to the embodiment of the present invention can diagnose the voltage abnormality of the battery cell by using the voltage variation of the battery cell without a separate current sensor, thereby detecting the abnormality due to the sudden voltage drop of the battery cell not only in a stationary state in which the voltage of the battery does not flow but also during the charge and discharge of the battery.

Fig. 3 is a view illustrating a diagnosis experiment on a defective cell by the battery diagnosis apparatus according to the embodiment of the present invention when the battery is charged.

Referring to fig. 3, the horizontal axis represents time (seconds), the vertical axis (left) represents voltage, and the vertical axis (right) represents current. In addition, the graph of fig. 3 represents the voltage of a normal cell, the voltage of a defective cell, the average voltage of a plurality of cells, and the charge current of the battery, which are measured in a charged state, respectively.

As shown in fig. 3, the average cell voltage variation, the voltage variation of the normal cell, and the voltage variation of the defective cell in one second can be expressed as follows. In addition, the threshold value when diagnosing an abnormal voltage drop of the battery was set to 15 mV. Meanwhile, in fig. 3, the time interval is set to one second, and the threshold is set to 15 mV. However, the user can arbitrarily set the time interval and the threshold value.

Average voltage variation of the battery cell:

ΔV_{monomer, average}Either as 0V (4.083V unchanged)

Voltage change of normal cell:

ΔV_{monomer, Normal}＝4.097V-4.098V＝-0.001V

| -0.001V-0V | < threshold (15mV)

Voltage variation of defective cell:

ΔV_{monomer, disorder}＝4.123V-4.095V＝0.028V

|0.028V-0V | > threshold (15mV)

As described above, in the case of a normal battery cell, the difference between the individual voltage variation and the average voltage variation is smaller than the threshold value, so that it is not determined as an abnormal voltage drop. However, in the case of a defective battery cell, the difference between the individual voltage variation and the average voltage variation is greater than a threshold value, so that it may be determined as an abnormal voltage drop.

Fig. 4 is a view illustrating a diagnostic experiment on a defective cell by the battery diagnostic apparatus according to the embodiment of the present invention when the battery is in a stationary state.

Referring to fig. 4, the horizontal axis represents time (seconds), the vertical axis (left) represents voltage, and the vertical axis (right) represents current. In addition, the graph of fig. 4 represents the voltage of the normal battery cell, the voltage of the defective battery cell, the average voltage of the plurality of cells, and the charge current of the battery, which are respectively measured in the stationary state.

In fig. 4, as in the case of fig. 3, the average voltage variation of the battery cell, the voltage variation of the normal battery cell, and the voltage variation of the defective battery cell within one second can be expressed as follows. In addition, the threshold value when diagnosing an abnormal voltage drop of the battery was set to 15 mV.

Average voltage variation of the battery cell:

ΔV_{monomer, average}0V (4.142V unchanged)

Voltage change of normal cell:

ΔV_{monomer, Normal}＝0V

|0V-0V | < threshold (15mV)

Voltage variation of defective cell:

ΔV_{monomer, disorder}＝4.123V-4.095V＝0.028V

|0.028V-0V | > threshold (15mV)

As described above, in the case of a normal battery cell, the difference between the individual voltage variation and the average voltage variation is smaller than the threshold value, so that it is not determined as an abnormal voltage drop. However, in the case of a defective battery cell, the difference between the individual voltage variation and the average voltage variation is greater than a threshold value, so that it may be determined as an abnormal voltage drop.

As described above, the battery diagnosis device according to the embodiment of the present invention can detect the abnormal voltage drop of the battery cell during the charge/discharge of the battery without confirming whether the battery is in a stationary state through the current sensor.

Fig. 5 is a flowchart illustrating a battery diagnosis method according to an embodiment of the present invention.

Referring to fig. 5, first, the voltage of each battery cell is measured during a preset time period (step S510). At this time, the period of time for measuring the voltage of the battery cell may be arbitrarily set by the user.

Thereafter, individual voltage changes of each battery cell are calculated during a preset time period (step S520). In step S520, it is possible to calculate a voltage change of each battery cell not only in a stationary state in which no current flows in the battery cell but also during the charge or discharge of the battery cell.

Next, average voltage variations of the plurality of battery cells are calculated during a preset time period (step S530). At this time, the average voltage variation of all the battery cells included in a specific battery pack may be calculated.

In addition, in steps S520 and S530, in order to reduce the influence due to the resistance of the battery itself, the voltage variation of each cell is calculated for a section in which the SOC of the cell is equal to or greater than the reference value.

Thereafter, when there is a battery cell in which the difference between the individual voltage variation calculated in step S520 and the average voltage variation calculated in step S530 is greater than the threshold value, it is determined that a voltage abnormality has occurred in the corresponding battery cell (step S540).

In this case, the threshold of step S540 may be set according to manufacturer-specific specifications of the battery cells and the voltage measuring unit (e.g., the battery management system BMS). For example, the threshold value may be set in consideration of a voltage measurement error of the voltage measurement unit, a capacity error between the battery cells generated during the assembly of the battery module, and the like.

As described above, according to the method for diagnosing a battery according to the embodiment of the present invention, the voltage abnormality of the battery cell is diagnosed by using the voltage variation of the battery cell without a separate current sensor. Therefore, it is possible to detect an abnormality due to an abrupt voltage drop of the battery not only during the charge and discharge of the battery but also in a stationary state in which the voltage of the battery does not flow.

Fig. 6 is a view showing a configuration of hardware according to an embodiment of the present invention.

As shown in fig. 6, the battery management apparatus 600 may have: a Microcontroller (MCU)610, the microcontroller 610 for controlling various processes and each part; a memory 620 in which an operating system program, various programs (for example, a battery pack abnormality diagnosis program or a battery pack temperature estimation program), and the like are stored; an input/output interface 630, the input/output interface 630 for providing an input interface and an output interface between the battery cell modules and/or the switching units (e.g., semiconductor switching elements); and a communication interface 640, the communication interface 640 being capable of communicating with the outside (e.g., an upper controller) through a wired/wireless communication network. As described above, the computer program according to the present invention is stored in the memory 620 and processed by the microcontroller 610, and thus may be implemented, for example, as a module that executes each functional block shown in fig. 2.

In the above, even though it has been described that all the components constituting the embodiments of the present invention are combined or combined to operate as one component, the present invention is not necessarily limited to these embodiments. That is, all components may be selectively combined and operated as one or more components if within the scope of the present invention.

In addition, unless explicitly stated otherwise, the terms "comprising," "including," or "having," as used herein, mean that the corresponding elements may be inherent, and should be interpreted as including but not excluding other elements. Unless otherwise defined, all terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Unless explicitly defined in the present disclosure, terms commonly used as defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made by those skilled in the art to which the present invention pertains without departing from the essential features of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but are for explanation, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of the present invention should be construed by the appended claims, and all technical ideas within the scope of the present invention should be construed as being included in the scope of the claims.