KR20190071342A - Apparatus and method for diagnosings battery cell - Google Patents

Abstract

According to the present invention, provided is an apparatus for diagnosing a battery cell, which comprises: a sensing unit measuring a cell voltage of a battery cell; and a processor operatively coupled with the sensing unit. The processor uses one of a first cell voltage, a second cell voltage, and a third cell voltage measured at the first point, the second point, and the third point, respectively, calculates an initial cell voltage change index and a late cell voltage change index, uses the initial cell voltage change index and the late cell voltage change index to calculate the total cell voltage change index, and compares the magnitude between the total cell voltage change index and a reference index to diagnose whether the amount of self-discharge of the battery cell is normal.

Description

[0001] Apparatus and method for diagnosing battery cells [0002]

The present invention relates to a battery cell diagnosis apparatus and method, and more particularly, to a battery cell diagnosis apparatus and method for diagnosing whether a self-discharge amount of a battery cell is normal using a cell voltage of a battery cell measured at a plurality of points of time .

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.

The secondary cell is designed such that a certain cell voltage is maintained based on the initial cell voltage even if a certain period of time elapses in an environment in which charge and discharge are not performed to receive or output power from the outside.

For this, a secondary battery having a measured self-discharge amount equal to or greater than a reference self-discharge amount is diagnosed as a defective product after a certain period of time has elapsed from the production of the secondary battery in the same process.

After the elapse of a longer period of time from the first diagnosis point of the secondary batteries not diagnosed as defective, the secondary battery whose measured self discharge amount is equal to or greater than the reference self discharge amount is diagnosed as a second defective product.

That is, in the conventional diagnosis method, the secondary cells self-discharge for a long period of time, and the defective products are selected by performing the diagnosis through the second order.

Accordingly, the conventional diagnostic method requires a long period of time from the production of the secondary batteries to the shipment, and requires a plurality of voltage measurement and diagnosis processes.

The present invention calculates the total cell voltage variation index using the first cell voltage, the second cell voltage and the third cell voltage measured at the first point of time, the second point of time and the third point of time, It is an object of the present invention to provide a battery cell diagnosis apparatus and method capable of diagnosing whether a self-discharge amount of a battery cell is normal or not by comparing magnitudes of exponents.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description and more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a battery cell diagnosis apparatus comprising: a sensing unit for measuring a cell voltage of a battery cell; And a processor operatively coupled to the sensing unit.

Preferably, the processor calculates the initial cell voltage variation index and the latest cell voltage variation using at least one of the first cell voltage, the second cell voltage, and the third cell voltage measured at the first point of time, the second point of time, Calculating a total cell voltage variation index by using the initial cell voltage variation index and the latest cell voltage variation index, comparing the total cell voltage variation index with a reference index, It is possible to diagnose whether the discharge amount is normal or not.

Preferably, the processor is configured to measure the second cell voltage measured at the second time point after the first time elapses from the first time point after the final charge / discharge of the battery cell is completed, and the second time from the second point- The initial cell voltage difference between the third cell voltage measured at the third time point that has elapsed can be calculated as the initial cell voltage variation index.

The processor may calculate the cell voltage change index using the voltage ratio between the first cell voltage and the initial cell voltage difference.

The processor may calculate the total cell voltage variation index by multiplying the initial cell voltage variation index by the latest cell voltage variation index.

Preferably, the processor can diagnose that the self-discharge amount of the battery cell is abnormal if the total cell voltage variation index is equal to or greater than the reference exponent.

Preferably, the processor can diagnose that the self-discharge amount of the battery cell is normal if the total cell voltage variation index is less than the reference index.

According to the present invention, the total cell voltage variation index is calculated using the first cell voltage, the second cell voltage, and the third cell voltage measured at the first point of time, the second point of time, and the third point of time, By comparing the magnitude of the self-discharge amount of the battery cell with the magnitude of the self-discharge amount of the battery cell, it is possible to minimize the diagnosis time and diagnosis process for diagnosing whether the self-discharge amount of the battery cell is normal.

1 is a block diagram showing the configuration of a battery cell diagnosis apparatus according to an embodiment of the present invention.
2 is a circuit diagram illustrating a connection structure between a battery cell diagnosis apparatus and a battery cell according to an embodiment of the present invention.
3 is a graph showing cell voltages of a battery cell diagnosed by the battery cell diagnosis apparatus according to an embodiment of the present invention with time.
FIG. 4 is a graph showing the last cell voltage variation index and the total cell voltage variation index calculated from the battery cell diagnosis apparatus according to an embodiment of the present invention.

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 construed as 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.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Terms including ordinals, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to define components by such terms.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise. In addition, the term " control unit " as described in the specification means a unit for processing at least one function or operation, and may be implemented by hardware or software, or a combination of hardware and software.

In addition, throughout the specification, when a portion is referred to as being "connected" to another portion, it is not necessarily the case that it is "directly connected", but also "indirectly connected" .

Hereinafter, a battery cell diagnostic apparatus 100 according to an embodiment of the present invention will be described.

FIG. 1 is a block diagram illustrating a configuration of a battery cell diagnosis apparatus 100 according to an embodiment of the present invention. FIG. 2 is a block diagram of a battery cell diagnosis apparatus 100 according to an embodiment of the present invention, ) Connected to each other.

Referring to FIGS. 1 and 2, a battery cell diagnostic apparatus 100 according to an embodiment of the present invention determines whether or not the self-discharge amount of the battery cell 200 is normal before the battery cell 200, Can be diagnosed. In other words, the battery cell diagnostic apparatus 100 according to an embodiment of the present invention can detect a normal (or non-normal) amount of self discharge of the battery cell 200 in a state where the battery cell 200 that has been manufactured is not charged / Can be diagnosed.

The battery cell diagnosis apparatus 100 may include a sensing unit 110, a memory unit 120, a processor 130, and a notification unit 140.

The sensing unit 110 is operably coupled to the processor 130. That is, the sensing unit 110 may be connected to the processor 130 to transmit an electrical signal to the processor 130 or to receive an electrical signal from the processor 130.

The sensing unit 110 measures the cell voltage applied between the positive terminal (+) and the negative terminal (-) of the battery cell 200 according to a predetermined period, a preset time, or sensing control of the processor 130.

More specifically, the sensing unit 110 measures the cell voltage of the battery cell 200 at a specific time according to the sensing control of the processor 130, and provides a measurement signal indicating the measured cell voltage to the processor 130 .

To this end, the sensing unit 110 includes a voltage sensor configured to measure the voltage of the battery cell 200.

When the measurement signal is received from the sensing unit 110, the processor 130 may determine the digital value of the measured cell voltage through the signal processing and store it in the memory unit 120. [

The memory unit 120 is a semiconductor memory device that writes, erases, and updates data generated by the processor 130, and generates a plurality of program codes for diagnosing whether the self-discharge amount of the battery cell 200 is normal . In addition, the memory unit 120 may store reference values and setting values used when the present invention is implemented.

There is no particular limitation on the kind of the semiconductor memory device as long as it is a semiconductor memory device known to be capable of writing, erasing and updating data. As one example, the memory unit 120 may be a DRAM, an SDRAM, a flash memory, a ROM, an EEPROM, a register, or the like. The memory unit 120 may further include a storage medium storing program codes that define the control logic of the processor 130. [ The storage medium includes an inert storage element such as a flash memory or a hard disk. The memory unit 120 may be physically separated from the processor 130, or may be integrated with the processor 130.

The processor 130 calculates an initial cell voltage variation index and a latest cell voltage variation index using the cell voltage of the battery cell 200 that has been manufactured, The voltage change index can be calculated.

To this end, the processor 130 controls the sensing unit 110 to acquire the cell voltage of the battery cell 200 after the electric state of the battery cell 200 charged / discharged in the manufacturing process is switched to the stabilized state can do.

That is, the processor 130 does not acquire the cell voltage of the battery cell 200 by controlling the sensing unit 110 at the time when the manufacture of the battery cell 200 is completed, The cell voltage of the battery cell 200 can be obtained by controlling the sensing unit 110 after a predetermined waiting time.

Here, the preset waiting time may be 12 hours, and the predetermined waiting time may be changed according to the type and capacity of the battery cell 200. [

In other words, the processor 130 may control the sensing unit 110 to acquire an open circuit voltage (OCV) of the manufactured battery cell 200 as a cell voltage.

3 is a graph showing cell voltages of a battery cell diagnosed by the battery cell diagnosis apparatus according to an embodiment of the present invention with time.

3, the processor 130 calculates the first cell voltage OCVt0 of the battery cell 200 measured at the first point of time t0, the second point of time t1 and the third point of time t3, The initial cell voltage variation index and the latest cell voltage variation index can be calculated using at least one of the second cell voltage OCVt1 and the third cell voltage OCVt2.

Here, the first time point t0 may be after the final charge / discharge in the charge / discharge performed in the manufacturing process of the battery cell 200 is completed. That is, the first time point t0 may be a time point at which the electrical state of the battery cell 200 is switched to the stabilized state after the final charge / discharge in the charge / discharge performed in the manufacturing process of the battery cell 200 is completed.

The second time point t1 may be a time point at which the first time point has elapsed from the first point of time t0 and the third point of time t3 may be the point at which the second time point has elapsed from the second point of time t1.

For example, the first time may be 12 days, and the second time may be 7 days. In this case, the second time point t1 and the third time point t3 may be the time points of 12 days and 19 days from the first time point t0, respectively. At this time, the processor 130 calculates the first cell voltage OCVt0 measured at the first time point t0, the second cell voltage OCVt0 measured at the second point of time t1 after 12 days from the first point of time t0, And OCVt2 measured at a third time point t3 when 19 days have passed since the first cell voltage OCVt1 and the first cell voltage t0 have been used to calculate the initial cell voltage variation index and the latter cell voltage variation index can do.

3, after completion of the final charge and discharge in the manufacturing process of the battery cell 200, if the battery cell 200 is not further charged or discharged, the self- The cell voltage can be reduced.

The battery cell 200 can be reduced to a fixed voltage by maintaining a cell voltage higher than a certain level within a certain period of time although the cell voltage can be reduced due to self discharge.

To this end, the processor 130 may compare the total cell voltage variation index with the reference index to determine whether the self discharge amount of the battery cell 200 is normal.

Previously, the processor 130 may calculate an initial cell voltage difference between the second cell voltage OCV1 and the third cell voltage OCV2 as an initial cell voltage variation index. At this time, the processor 130 may calculate an initial cell voltage change index using Equation (1) below.

&Quot; (1) "

OCVt1 is the second cell voltage OCV1 of the battery cell 200 measured at the second point of time t1 and OCVt2 is the voltage of the battery cell 200 measured at the third point of time t2, (OCV2) of the first cell voltage (OCV2).

Accordingly, the processor 130 may exponentially calculate the cell voltage change of the battery cell 200 between the second time point t1 and the third time point t2.

Meanwhile, the processor 130 may calculate the late cell voltage change index using the voltage ratio between the first cell voltage OCV0 and the initial cell voltage difference. At this time, the processor 130 may calculate the post cell voltage variation index using the following equation (2).

&Quot; (2) "

In this case,? Is a cell voltage change index of late, t1 is a second time point t1, t2 is a third time point t2, and OCVt0 is a first cell voltage of the battery cell 200 measured at a first time point t0 OCVt1 is the second cell voltage OCV1 of the battery cell 200 measured at the second time point t1 and OCVt2 is the third cell voltage OCV2 of the battery cell 200 measured at the third time point t2 OCV2).

Accordingly, the processor 130 can exponentially calculate the cell voltage change of the battery cell 200 after the third time point t2.

Thereafter, the processor 130 may calculate the total cell voltage change index using the calculated initial cell voltage change index and the calculated late cell voltage change index. More specifically, the processor 130 may calculate the total cell voltage variation index by multiplying the initial cell voltage variation index and the latter cell voltage variation index. At this time, the processor 130 may calculate the total cell voltage change index using the following equation (3).

&Quot; (3) "

T1 is a second time point t1, t2 is a third time point t2, and OCVt0 is a first time point (t1) OCVt1 of the battery cell 200 measured at the second point of time t0 is the second cell voltage OCV1 of the battery cell 200 measured at the second point of time t1 and OCVt2 of the battery cell 200 measured at the third point of time t1, and the third cell voltage OCV2 of the battery cell 200 measured at time t2.

The processor 130 may compare the magnitude of the calculated total cell voltage change index index to diagnose whether the self discharge amount of the battery cell 200 is normal or not. Here, the reference index may be a reference value for diagnosing whether the self-discharge amount of the battery cell 200 is normal.

More specifically, the processor 130 can diagnose that the self-discharge amount of the battery cell 200 is abnormal when the total cell voltage variation index is equal to or greater than the reference index. That is, when the total cell voltage variation index is equal to or greater than the reference index, the processor 130 determines that the self discharge amount of the corresponding battery cell 200 exceeds the self discharge amount required at the time of shipment, Can be diagnosed.

Conversely, the processor 130 can diagnose that the self-discharge amount of the battery cell 200 is normal if the total cell voltage variation index is less than the reference index. That is, when the total cell voltage variation index is less than the reference index, the processor 130 determines that the amount of self discharge of the battery cell 200 is less than the self discharge amount required when the battery cell 200 is shipped. can do.

FIG. 4 is a graph showing the late cell voltage change index and the total cell voltage change index calculated from the battery cell diagnostic apparatus according to an embodiment of the present invention and another embodiment.

4, the processor 130 according to an exemplary embodiment sets a reference index corresponding to the type and capacity of the battery cell 200, ) Is normal or not.

For example, as shown in FIG. 4, the processor 130 calculates the total cell voltage variation index of each of the plurality of battery cells 200, sets the reference index to "3" It is possible to diagnose whether the self-discharge amount of the battery cells is normal by comparing the total cell voltage variation index with the reference index "3 ".

The processor 130 may diagnose only the battery cells whose total cell voltage variation index is equal to or greater than the reference index "3 " as a regular product and battery cells whose total cell voltage variation index is less than the reference index" 3 "

According to the present invention described above, the processor 130 can easily calculate the total cell voltage variation index (BER) using the cell voltages of the battery cell 200 measured at the first point of view, the second point of view, And it is possible to easily and quickly diagnose whether the self-discharge amount of the battery cell 200 is normal through the process of comparing the calculated total voltage variation index and the reference index.

In addition, according to the present invention, the processor 130 self-discharges the battery cell 200 to the third time point without self-discharging the battery cell 200 for a long time, thereby determining whether the self-discharge amount of the battery cell 200 is normal Thus, it is not necessary to store the battery cell 200 for a long time, and the battery cell 200 can be completed after the completion of the diagnosis.

Meanwhile, the processor 130 according to another embodiment sets the initial reference index and the late reference index corresponding to the electrical characteristics of the battery cell 200, and sets the initial reference index and the late reference index, Can be set.

More specifically, the processor 130 sets a value calculated by multiplying the set initial index and a late reference index as a reference index, compares the total cell voltage variation index of the battery cell 200 with a set reference index, It is possible to diagnose whether or not the self-discharge amount is normal.

At this time, the processor 130 sets the maximum value of the initial cell voltage change index required from the battery cell 200 as an initial reference index, and sets the maximum value of the latest cell voltage change index required from the battery cell 200 as a late reference value Can be set to exponent.

In this way, the processor 130 not only reflects the initial cell voltage variation index and the latter cell voltage variation index from the battery cell 200, but also reflects the initial cell voltage variation index and the latter cell voltage variation index You can set the exponent.

For example, when the initial reference index and the latter reference index are set to "3" and "1", the processor 130 can set "3" calculated by multiplying "3" and "1" . At this time, when the processor 130 calculates the initial cell voltage variation index and the latter cell voltage variation index of the battery cell 200 as " 3.1 "and" 0.8 " Even if the initial cell voltage variation index exceeds the initial reference index, the total cell voltage variation index is less than the reference index, so that the self-discharge amount of the battery cell 200 can be diagnosed to be normal.

As described above, the processor 130 according to another embodiment reflects both the initial cell voltage variation index and the latter cell voltage variation index required from the battery cell 200, and at the same time, the initial cell voltage variation index and the late cell voltage variation index It is possible to diagnose that the self discharge amount of the battery cell 200 is normal by considering both the initial cell voltage change and the latest cell voltage change by setting a reference index that is not limited to one.

Processor 130 may optionally include a processor, an application-specific integrated circuit (ASIC), other chipset, logic circuit, register, communication modem, data processing device, etc., have. At least one of the various control logic executable by the processor 130 may be combined and the combined control logic may be written in a computer-readable code system and stored in a computer-readable recording medium. The recording medium is not particularly limited as long as it can be accessed by a processor included in the computer. As one example, the recording medium includes at least one selected from the group including ROM, RAM, register, CD-ROM, magnetic tape, hard disk, floppy disk and optical data recording device.

Meanwhile, the battery cell diagnostic apparatus 100 according to the present invention may further include a notification unit.

The notification unit receives the diagnosis result of the processor 130, receives the diagnosis result of the processor 130 stored in the memory unit 120, and outputs the received diagnosis result to the outside.

More specifically, the notification unit may include at least one of a display unit that displays the diagnosis result using one or more of symbols, numbers, and codes, and a speaker unit that outputs a diagnostic result to a sound.

When the battery cell diagnostic apparatus 100 according to the present invention is included in a vehicle and the processor 100 of the battery cell diagnostic apparatus 100 performs a diagnosis on the battery cell 200 included in the vehicle, And a communication unit for outputting a signal including the diagnosis result to an ECU (Electronic Control Unit) of the vehicle.

Meanwhile, the battery pack according to the present invention may include the battery cell diagnostic apparatus 100 described above.

The embodiments of the present invention described above are not only implemented by the apparatus and method but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded, The embodiments can be easily implemented by those skilled in the art from the description of the embodiments described above.

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.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative, The present invention is not limited to the drawings, but all or some of the embodiments may be selectively combined so that various modifications may be made.

100: Battery cell diagnostic device
110: sensing unit 120: memory unit
130:
200: battery cell

Claims (7)

A sensing unit for measuring a cell voltage of the battery cell; And
And a processor operatively coupled to the sensing unit,
The processor
The initial cell voltage variation index and the late cell voltage variation index are calculated using at least one of the first cell voltage, the second cell voltage and the third cell voltage measured at the first point of time, the second point of time, and the third point of time, A total cell voltage variation index is calculated using the initial cell voltage variation index and the latest cell voltage variation index, and whether the self discharge amount of the battery cell is normal or not is determined by comparing the total cell voltage variation index and the reference index A battery cell diagnostic device to diagnose.
The method according to claim 1,
The processor
The second cell voltage measured at the second time point after the first time elapses from the first time point after completion of the final charge and discharge of the battery cell and the second cell voltage measured at the third time point The initial cell voltage variation between the first cell voltage and the second cell voltage is measured.
3. The method of claim 2,
The processor
And calculates the latest cell voltage change index using a voltage ratio between the first cell voltage and the initial cell voltage difference.
The method according to claim 1,
The processor
And calculates a total cell voltage variation index by multiplying the initial cell voltage variation index by the latest cell voltage variation index.
The method according to claim 1,
The processor
And diagnoses that the self-discharge amount of the battery cell is abnormal if the total cell voltage variation index is greater than or equal to the reference index.
The method according to claim 1,
The processor
And diagnoses that the self-discharge amount of the battery cell is normal if the total cell voltage variation index is less than the reference index.
A battery pack including the battery cell diagnosis device according to any one of claims 1 to 6.

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