One]The present invention relates to a technique for determining the degree of degradation of a battery.
[2]
This application is a priority claim application for Korean Patent Application No. 10-2019-0056467 filed on May 14, 2019, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
background
[3]
Recently, as the demand for portable electronic products such as laptops, video cameras, and portable telephones is rapidly increasing, and development of electric vehicles, energy storage batteries, robots, satellites, etc. is in full swing, high-performance batteries that can be repeatedly charged and discharged have been developed. Research is being actively conducted.
[4]
Currently commercialized batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries. It is in the spotlight because of its low energy density and high energy density.
[5]
There is a prior art for determining the degree of deterioration of a battery from a capacity curve representing a correspondence relationship between a voltage and a power storage amount of the battery. However, in the capacity curve, when there is a power storage amount range in which a change in voltage is not clearly observed, it is difficult to accurately determine the degree of deterioration of the battery.
[6]
Another prior art for resolving the disadvantages of the capacity curve as described above uses differential voltage analysis (DVA) to determine the degree of degradation of the battery from the differential voltage curve of the battery. However, the differential voltage curve obtained by performing only one of the charging process and the discharging process on the battery does not sufficiently include information on the hysteresis characteristic of the battery.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[7]
The present invention has been devised to solve the above problems, and utilizes both the differential capacity curve obtained from the charging process for the battery and the differential capacity curve obtained from the discharging process for the battery to determine the degree of degradation of the battery. It aims to provide an apparatus, method and battery pack for determining.
[8]
Other objects and advantages of the present invention may be understood by the following description, and will become more clearly understood by the examples of the present invention. In addition, it will be readily apparent that the objects and advantages of the present invention can be realized by means and combinations thereof indicated in the claims.
means of solving the problem
[9]
An apparatus for determining the degree of degradation of a battery according to an aspect of the present invention generates first sensing information indicating the voltage and current of the battery during a first period in which the battery is charged with a first constant current, and a sensing unit configured to generate second sensing information indicating the voltage and current of the battery during a second period in which the battery is discharged with a second constant current; and a control unit operatively coupled to the sensing unit. The controller is configured to determine a first differential capacity curve of the battery based on the first sensing information. The control unit is configured to detect a first charging characteristic point from the first differential capacitance curve. The controller is configured to determine a second differential capacity curve of the battery based on the second sensing information. The control unit is configured to detect a first discharge characteristic point from the second differential capacity curve. The control unit is configured to determine a degree of degradation of the battery based on a first charging characteristic value and a first discharging characteristic value. The first charging characteristic value is a voltage value of the first charging characteristic point. The first discharge characteristic value is a voltage value of the first discharge characteristic point.
[10]
The control unit may be configured to determine, as the first charging feature point, a peak located in a first predetermined order among a predetermined number of peaks located on the first differential capacity curve. The control unit may be configured to determine, as the first discharge characteristic point, a peak located in the first predetermined order among a predetermined number of peaks located in the second differential capacity curve.
[11]
The control unit may be configured to determine a first main difference value indicating an absolute value of a difference between the first charging characteristic value and the first discharging characteristic value. The controller may be configured to determine the degree of degradation of the battery from a first data table in which a correspondence relationship between the first major difference value and the degree of degradation is recorded by using the first major difference value as an index.
[12]
The control unit may be configured to determine, as a second charging feature, a peak located in a second predetermined order among the predetermined number of peaks located on the first differential capacity curve when the predetermined number is two or more. The control unit may be configured to determine, as a second discharge characteristic point, a peak located in the second predetermined order among the predetermined number of peaks located on the second differential capacity curve. The control unit may be configured to determine a second main difference value indicating an absolute value of a difference between the second charging characteristic value and the second discharging characteristic value. The second charging characteristic value is a voltage value of the second charging characteristic point. The second discharge characteristic value is a voltage value of the second discharge characteristic point.
[13]
The control unit may be configured to determine the first degradation factor by using the following equation when the predetermined number is two.
[14]
[Equation]
[15]

[16]
ΔV i is the ith main difference value, α i is the ith predetermined weight, and F deg is the first degradation factor. The controller may be configured to determine the degree of degradation of the battery from a second data table in which a correspondence relationship between the first degradation factor and the degree of degradation is recorded by using the first degradation factor as an index.
[17]
The control unit may be configured to determine a first sub-difference value indicating an absolute value of a difference between the first charging characteristic value and the first initial charging characteristic value. The controller may be configured to determine a second sub-difference value indicating an absolute value of a difference between the first discharge characteristic value and the first initial discharge characteristic value. The controller may be configured to determine the degree of degradation of the battery based on the first sub-difference value and the second sub-difference value.
[18]
The controller may be configured to determine, as a second degradation factor, a sum of a product of the first sub-difference value and a first transform coefficient and a product of the second sub-difference value and a second transform coefficient. The controller may be configured to determine the degree of degradation of the battery from a third data table in which a correspondence relationship between the second degradation factor and the degree of degradation is recorded by using the second degradation factor as an index.
[19]
A battery pack according to another aspect of the present invention includes the device.
[20]
According to another aspect of the present invention, there is provided a method for determining a degree of deterioration of a battery, comprising: acquiring first sensing information indicating a voltage and current of the battery during a first period in which the battery is charged with a first constant current; acquiring second sensing information indicating the voltage and current of the battery during a second period in which the battery is discharged with a second constant current; determining a first differential capacity curve of the battery based on the first sensing information; determining a second differential capacity curve of the battery based on the second sensing information; detecting a first charging characteristic point from the first differential capacity curve; detecting a first discharge characteristic point from the second differential capacity curve; and determining the degree of degradation of the battery based on the first charging characteristic value and the first discharging characteristic value. The first charging characteristic value is a voltage value of the first charging characteristic point. The first discharge characteristic value is a voltage value of the first discharge characteristic point.
[21]
The determining of the degradation degree of the battery may include: determining a first main difference value representing an absolute value of a difference between the first charging characteristic value and the first discharging characteristic value; and determining the degree of degradation of the battery from a first data table in which a correspondence relationship between the first major difference value and the degree of degradation is recorded by using the first major difference value as an index.
Effects of the Invention
[22]
According to at least one of the embodiments of the present invention, the degree of deterioration of the battery may be determined by using both the differential capacity curve acquired from the charging process for the battery and the differential capacity curve acquired from the discharging process for the battery. Since the hysteresis characteristic of the battery has a strong correlation with the deterioration degree of the battery, the deterioration degree of the battery can be accurately determined compared to the case where only one of the two differential capacity curves is used.
[23]
Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.
Brief description of the drawing
[24]
The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention to be described later, so that the present invention is a matter described in such drawings should not be construed as being limited only to
[25]
1 is a diagram exemplarily showing the configuration of a battery pack according to an embodiment of the present invention.
[26]
2 is a graph exemplarily showing a capacity curve of a battery when the battery is in an initial state of its lifespan.
[27]
3 is a graph exemplarily showing a differential capacity curve determined from the capacity curve of FIG. 2 .
[28]
4 is a graph exemplarily showing a differential capacity curve of a battery when the battery is degraded from an initial state of life.
[29]
5 is a flowchart exemplarily showing a method for determining a deterioration degree of a battery according to the first embodiment of the present invention.
[30]
6 is a flowchart exemplarily showing a method for determining a degree of deterioration of a battery according to a second embodiment of the present invention.
[31]
7 is a flowchart exemplarily showing a method for determining a deterioration degree of a battery according to a third embodiment of the present invention.
Modes for carrying out the invention
[32]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention.
[33]
Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.
[34]
Terms including an ordinal number such as 1st, 2nd, etc. are used for the purpose of distinguishing any one of various components from the others, and are not used to limit the components by such terms.
[35]
Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated. In addition, a term such as described in the specification means a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.
[36]
In addition, throughout the specification, when a part is "connected" with another part, it is not only "directly connected" but also "indirectly connected" with another element interposed therebetween. include
[37]
1 is a diagram exemplarily showing the configuration of a battery pack according to an embodiment of the present invention.
[38]
Referring to FIG. 1 , a battery pack 10 is provided to be installed in an electric system 1 (eg, an electric vehicle), and includes a battery B, a switch SW, and a device 100 .
[39]
The positive and negative terminals of the battery B are electrically connected to the device 100 . The battery B includes at least one unit cell. The unit cell may be, for example, a lithium ion battery. Of course, the type of the unit cell is not limited to the lithium ion battery, and other types of battery cells capable of repeatedly charging and discharging may be used as the unit cell.
[40]
The switch SW is provided in the path of the current for charging and discharging the battery B. While the switch SW is turned on, charging and discharging of the battery B is possible. The switch SW may be a mechanical relay turned on and off by a magnetic force of a coil or a semiconductor switch such as a metal oxide semiconductor field effect transistor (MOSFET). While the switch SW is turned off, charging and discharging of the battery B is stopped. The switch SW may be turned on in response to the first switching signal. The switch SW may be turned off in response to the second switching signal.
[41]
Device 100 is provided for determining the degree of degradation of battery B. The deterioration degree may be a value that gradually increases according to the deterioration of the battery B.
[42]
The device 100 includes a sensing unit 110 , a control unit 120 , and a memory unit 130 . The device 100 may further include at least one of the interface unit 140 and the switch driver 200 .
[43]
The sensing unit 110 includes a voltage sensor 111 and a current sensor 112 .
[44]
The voltage sensor 111 is electrically connected to the positive terminal and the negative terminal of the battery B. The voltage sensor 111 is configured to measure the voltage across both ends of the battery B every unit time (eg, 0.01 seconds) while the battery B is being charged or discharged. The current sensor 112 is provided in the charging/discharging path of the battery B. The current sensor 112 is configured to measure the current of the battery B per unit time while the battery B is being charged or discharged.
[45]
The sensing unit 110 is configured to output sensing information indicating the voltage and current of the battery B for each unit time to the control unit 120 .
[46]
The controller 120, in hardware, ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors (microprocessors) and may be implemented using at least one of electrical units for performing other functions.
[47]
The control unit 120 is operatively coupled to at least one of the sensing unit 110 , the memory unit 130 , the interface unit 140 , and the switch driver 200 .
[48]
When at least one of the predetermined event(s) occurs, the controller 120 may instruct the switch driver 200 to turn on the switch SW. In other circumstances, the controller 120 may instruct the switch driver 200 to turn off the switch SW.
[49]
The control unit 120 is configured to store, in the memory unit 130 , data representing a voltage history, a current history, and a power storage history of the battery B based on the sensing information from the sensing unit 110 . The history of a certain parameter means a time-series change of the corresponding parameter over a certain period or a specific period. The voltage history, current history, and power storage amount history of the battery B may relate to the same period or different periods from each other. The amount of electricity stored in the battery B indicates the amount of charge stored in the battery B.
[50]
The controller 120 determines a first capacity curve and a second capacity curve of the battery B.
[51]
The first capacity curve shows that the battery B has a first current rate (eg, 0.02) from below a first state of charge (SOC) (eg, 5%) to above a second state of charge (eg, 95%). The correspondence between the voltage history and the power storage amount history obtained during the period of charging with the constant current of C) (hereinafter referred to as a 'first period') is shown. The first capacity curve is based on the first sensing information output by the sensing unit 110 for the first period and indicating the voltage and current of the battery B for each unit time. The controller 120 may control the switch driver 200 so that the charging current of the first current rate flows through the battery B during the first period.
[52]
The second capacity curve is a voltage history obtained during a period in which the battery B is discharged at a constant current at a second current rate from above the second state of charge to below the first state of charge (hereinafter referred to as a 'second period'). and the power storage history are shown. The second capacity curve is based on second sensing information output by the sensing unit 110 for the second period and indicating the voltage and current of the battery B for each unit time. The controller 120 may control the switch driver 200 so that a discharge current of the second current rate flows through the battery B during the second period. The second current rate may be the same as or different from the first current rate.
[53]
The controller 120 may determine the voltage change amount dV and the power storage amount change amount dQ of the battery B for each unit time from the first capacity curve. The control unit 120 stores, in the memory unit, a first data set, which is determined from the first capacity curve, indicating a correspondence relationship between the voltage V of the battery B, the amount of power storage Q, the amount of voltage change dV, and the amount of change of the power storage amount dQ for each unit time. It can be stored in (130).
[54]
The controller 120 may determine a first differential capacity curve from the first data set. The first differential capacity curve represents the relationship between the voltage V of the battery B and the ratio dQ/dV of the change in the power storage amount dQ of the battery B to the voltage change dV of the battery B during the first period, dQ/dV, It may also be referred to as a first V-dQ/dV curve.
[55]
The controller 120 may determine a voltage change amount dV and a power storage amount change amount dQ of the battery B for each unit time from the second capacity curve. The control unit 120 stores, in the memory unit, a second data set indicating a correspondence relationship between the voltage V of the battery B, the amount of power storage Q, the amount of voltage change dV, and the amount of change of the power storage amount dQ for each unit time, which is determined from the second capacity curve. It can be stored in (130).
[56]
The controller 120 may determine a second differential capacitance curve from the second data set. The second differential capacity curve represents the relationship between the voltage V of the battery B and the ratio dQ/dV of the change in the power storage amount dQ of the battery B to the voltage change dV of the battery B during the second period, dQ/dV, It may also be referred to as a second V-dQ/dV curve.
[57]
The memory unit 130 is operatively coupled to the control unit 120 . The memory unit 130 may also be operatively coupled to the sensing unit 110 . The memory unit 130 is configured to store sensing information from the sensing unit 110 . The memory unit 130 may store data and a program required for an arithmetic operation by the control unit 120 . The memory unit 130 may store data representing a result of an operation performed by the control unit 120 .
[58]
Memory unit 130, for example, a flash memory type (flash memory type), a hard disk type (hard disk type), an SSD type (Solid State Disk type), SDD type (Silicon Disk Drive type), a multimedia card micro type (multimedia) card micro type), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM) ) may include at least one type of storage medium.
[59]
The switch driver 200 is electrically coupled to the device 100 and the switch SW. The switch driver 200 is configured to selectively output a first switching signal or a second switching signal to the switch SW in response to a command from the device 100 .
[60]
The interface unit 140 is configured to support wired communication or wireless communication between the control unit 120 and the upper controller 2 (eg, ECU: Electronic Control Unit) of the electric system 1 . Wired communication may be, for example, CAN (controller area network) communication, and wireless communication may be, for example, Zigbee or Bluetooth communication. Of course, as long as wired/wireless communication between the control unit 120 and the upper controller 2 is supported, the type of the communication protocol is not particularly limited. The interface unit 140 may include an output device such as a display or a speaker that provides the result of the process related to the deterioration degree of the battery B performed by the control unit 120 in a form recognizable by a user. The interface unit 140 may include an input device, such as a mouse and a keyboard, that can receive data from a user.
[61]
FIG. 2 is a graph exemplarily showing a capacity curve of the battery when the battery is in an initial state of life, and FIG. 3 is a graph exemplarily showing a differential capacity curve determined from the capacity curve of FIG. 2 .
[62]
The maximum capacity Q max of the battery B is when the battery B is fully charged, that is, when the state of charge (SOC) of the battery B is 100%. can be the amount. The maximum capacity Q max of the battery B gradually decreases as the battery B deteriorates.
[63]
Referring to FIG. 2 , the capacity curve 201 shows the state of charge of the battery B from 0% to 100% with a constant current at a predetermined current rate when the battery B is in the beginning of life (BOL) state. The corresponding relationship between the voltage V of the battery B and the amount of storage Q obtained through the charging process is shown.
[64]
The capacity curve 202 is obtained through the process of discharging the state of charge of the battery B from 100% to 0% with a constant current at a predetermined current rate when the battery B is in the initial state of its life. Shows the correspondence between voltage V and capacitance Q.
[65]
Due to the hysteresis characteristic of the battery B, within at least a partial power storage amount range between 0 and Q max, the difference between the voltage of the capacity curve 201 and the voltage of the capacity curve 202 at the same power storage amount is a predetermined exceeds the threshold.
[66]
Referring to FIG. 3 , the differential capacitance curve 301 is determined from the relationship between the voltage history and the power storage amount history indicated by the capacitance curve 201 . The differential capacitance curve 302 is determined from the relationship between the voltage history and the power storage amount history indicated by the capacitance curve 202 . For ease of understanding, with respect to the axis where dQ/dV = 0 Ah/V, the differential capacitance curve 301 is shown at the top, and the differential capacitance curve 302 is shown at the bottom.
[67]
Differential capacity curve 301 peak (P positioned CI_1 , P CI_2 , P CI_3 peak (P which is located on the total number and differential capacity curve 302) DI_1 , P DI_2 , P DI_3 number of) may be the same have. The total number of peaks located in each of the differential capacity curve 301 and the differential capacity curve 302 depends on the electrode material of the battery B or the like. Accordingly, even if the battery B is degraded, the total number of peaks located in each of the differential capacity curve 301 and the differential capacity curve 302 may be constant. Hereinafter, the total number of peaks ( PCI_1 , PCI_2 , PCI_3 ) appearing in the differential capacity curve 301 and the total number of peaks (P DI_1 , P DI_2 , P DI_3 ) located in the differential capacity curve 302 are Assume that there are three each.
[68]
In the memory unit 130 , charging characteristic values ​​('initial charging) indicating voltage values ​​(V CI_1 , V CI_2 , V CI_3 ) of peaks ( PCI_1 , PCI_2 , PCI_3 ) located in the differential capacity curve 301 , respectively feature value) may be stored.
[69]
In the memory unit 130, the peaks (P DI_1 , P DI_2 , P DI_3 ) located on the differential capacity curve 302 , respectively, voltage values ​​(V DI_1 , V DI_2 , V DI_3 ) of discharge characteristic values ​​('initial discharge) feature value) may be stored.
[70]
The inventor of the present invention has recognized the fact that the hysteresis characteristic of the battery (B) becomes worse as the battery (B) deteriorates from the results of the charging and discharging experiments on the battery having the same specifications as the battery (B).
[71]
4 is a graph exemplarily showing a differential capacity curve of a battery when the battery is degraded from an initial state of life.
[72]
Referring to FIG. 4 , the differential capacitance curve 401 is determined from the relationship between the voltage history and the power storage amount history during the first period. The differential capacitance curve 402 is determined from the relationship between the voltage history and the power storage amount history during the second period. For ease of understanding, based on dQ/dV = 0, the differential capacitance curve 401 is shown at the top, and the differential capacitance curve 402 is shown at the bottom.
[73]
Differential capacity curve 401, the differential capacitance curve peak (P shown in (301) CI_1 , P CI_2 , P CI_3 ) and the peak (P of the same number CD_1 , P CD_2 , P CD_3 is a) position. Differential capacity curve 402, the differential capacity curve 302 peak (P shown in DI_1 , P DI_2 , P DI_3 ) and the peak (P of the same number DD_1 , P DD_2 , P DD_3 is a) position.
[74]
In the differential capacitance curve 401 , a peak P CD_1 , a peak P CD_2 , and a peak P CD_3 are located in the order of the small power storage amount . Differential capacitance peak (P that appears in the curve (401) CD_1 , P CD_2 , P CD_3 ) is, in order to peak (P that appears in the differential capacity curve (301) CI_1 , P CI_2 , P CI_3 corresponds to). Each of the peaks (P CD_1 , P CD_2 , P CD_3 ) is called a 'charging feature point', and voltage values ​​(V CD_1 , V CD_2 , V ) of the peaks (P CD_1 , P CD_2 , P CD_3 ) CD_3 ) may each be referred to as a 'charging feature value'.
[75]
In the differential capacitance curve 402 , a peak P DD_1 , a peak P DD_2 , and a peak P DD_3 are located in the order of the small power storage amount . Differential capacitance peak (P that appears in the curve (402) DD_1 , P DD_2 , P DD_3 ) is, in order to peak (P that appears in the differential capacity curve (302) DI_1 , P DI_2 , P DI_3 corresponds to). Each of the peaks (P DD_1 , P DD_2 , P DD_3 ) is referred to as a 'discharge feature point', and voltage values ​​(V DD_1 , V DD_2 , V ) of the peaks (P DD_1 , P DD_2 , P DD_3 ) DD_3 ) may be referred to as 'discharge feature values'.
[76]
2 to 4 , as the battery B deteriorates, (I ) the charging characteristic values ​​V CD_1 , V CD_2 of the peaks P CD_1 , P CD_2 , P CD_3 located in the differential capacity curve 401 . , V CD_3 ) increases from the initial charge characteristic values ​​(V CI_1 , V CI_2 , V CI_3 ) of peaks ( PCI_1 , PCI_2 , PCI_3 ) located in the same order of the differential capacity curve 301 , and (II ) discharge characteristic values ​​(V DD_1 , V DD_2 ) of the peaks (P DD_1 , P DD_2 , P DD_3 ) located on the differential capacity curve 402 . , V DD_3 ) It can be seen that the initial discharge characteristic values ​​(V DI_1 , V DI_2 , V DI_3 ) of the peaks (P DI_1 , P DI_2 , P DI_3 ) located in the same order of the differential capacity curve 302 are decreased from have. That is, the peak of the battery the more (B) a degenerated, differential capacity curve (401) (P CD_1 , P CD_2 , P CD_3 ) is of becoming shifted in the high voltage range, a differential capacity curve 402, the peak (P DD_1 , P DD_2 , P DD_3 ) is shifted to the low voltage band.
[77]
In the same order (e.g., first) two peaks (for example, P may appear on the inventors of the present invention, a differential capacity curve 401 and the differential capacity curve (402) CD_1 , P DD_1 voltage value) (for example, V CD_1 , V DD_1 ) was found to have a strong correlation with the degradation degree of the battery (B).
[78]
5 is a flowchart exemplarily showing a method for determining a deterioration degree of a battery according to the first embodiment of the present invention. The method of FIG. 5 may be utilized to determine the degree of degradation of the battery B in which at least one peak appears in the differential capacity curve.
[79]
1 to 5 , in step S502 , the control unit 120 senses first sensing information indicating the voltage and current of the battery B during the first period charged with the first constant current to the sensing unit 110 . obtained from
[80]
In step S504 , the control unit 120 acquires, from the sensing unit 110 , second sensing information indicating the voltage and current of the battery B during the second period to be discharged with the second constant current.
[81]
In step S512 , the controller 120 determines a first differential capacity curve of the battery B based on the first sensing information. For example, the first differential capacitance curve may be the differential capacitance curve 401 of FIG. 4 .
[82]
In step S514 , the controller 120 determines a second differential capacity curve of the battery B based on the second sensing information. For example, the second differential capacitance curve may be the differential capacitance curve 402 of FIG. 4 .
[83]
In step S522 , the control unit 120 detects a charging feature point (eg, P CD_2 ) from the first differential capacity curve . The charging feature point (eg, P CD_2 ) may be a peak located in a predetermined order (eg, the second) based on the power storage amount among all the peaks of the first differential capacity curve.
[84]
In step S524 , the controller 120 detects a discharge characteristic point (eg, P DD_2 ) from the second differential capacity curve . The discharge characteristic point (eg, P DD_2 ) may be a peak located in the predetermined order (eg, the second) based on the amount of power storage among all peaks of the second differential capacity curve.
[85]
In step S530 , the controller 120 determines the degree of degradation of the battery B based on the main difference value. The main difference is, the charging characteristic value (for example, V CD_2 ) and discharge characteristic value (for example, V DD_2 (e.g., the absolute value of the difference between │V) CD_2 - V DD_2 a │). The charging characteristic value (eg, V CD_2 ) is the voltage value of the charging characteristic (eg, P CD_2 ), and the discharge characteristic value (eg, V DD_2 ) is the voltage value of the discharge characteristic (eg, P DD_2 ). The controller 120 determines the degree of degradation of the battery B from the first data table in which a correspondence relationship between the major difference value and the degree of degradation is recorded by using the major difference value determined in step S530 as an index.
[86]
The first data table may be previously stored in the memory unit 130 . As the hysteresis characteristic of the battery B becomes stronger, the main difference value tends to increase. Accordingly, in the first data table, a relatively large main difference value may be associated with a relatively large degree of degradation.
[87]
6 is a flowchart exemplarily showing a method for determining a degree of deterioration of a battery according to a second embodiment of the present invention. The method of FIG. 6 may be utilized to determine the degree of degradation of the battery B in which at least two peaks appear in the differential capacity curve.
[88]
1 to 4 and 6 , in step S602 , the controller 120 senses first sensing information indicating the voltage and current of the battery B during the first period charged with the first constant current. It is obtained from (110).
[89]
In step S604 , the control unit 120 acquires, from the sensing unit 110 , second sensing information indicating the voltage and current of the battery B during the second period to be discharged with the second constant current.
[90]
In step S612 , the controller 120 determines a first differential capacity curve of the battery B based on the first sensing information. For example, the first differential capacitance curve may be the differential capacitance curve 401 of FIG. 4 .
[91]
In step S614 , the controller 120 determines a second differential capacity curve of the battery B based on the second sensing information. For example, the second differential capacitance curve may be the differential capacitance curve 402 of FIG. 4 .
[92]
In step S622 , the control unit 120 detects first to nth charging characteristic points from the first differential capacity curve. n is a natural number equal to or greater than 2, and is a predetermined value representing a number equal to or less than the total number of peaks located on the first differential capacity curve. When i = 1 to n, the i-th charging feature point may be a peak located at the i-th among the first to n-th charging feature points based on the amount of power storage.
[93]
In step S624, the control unit 120 detects first to nth discharge characteristic points from the second differential capacitance curve. The ith discharge characteristic point may be a peak located at the ith position among the first to n-th discharge characteristic points based on the amount of power storage.
[94]
In step S630 , the controller 120 determines the degree of degradation of the battery B based on the first to nth main difference values. When i = 1 to n, the ith main difference value may be an absolute value of the difference between the ith charge characteristic value and the ith discharge characteristic value. The ith charge characteristic value is a voltage value of the ith charging characteristic point, and the ith discharge characteristic value is a voltage value of the ith discharge characteristic point. Then, the controller 120 determines a first degradation factor from the first to nth main difference values. The controller 120 may determine the first degradation factor using Equation 1 below.
[95]
[Equation 1]
[96]

[97]
In Equation 1, ΔV i is the ith main difference value, V CD_i is the ith charge characteristic value, V DD_i is the ith discharge characteristic value, α i is the ith predetermined weight, and F deg is the first degradation factor. α i may be a predetermined value based on an increase rate of the ith charge characteristic value and a decrease rate of the ith discharge characteristic value according to the deterioration of the battery B . The increase rate of the ith charging characteristic value may be a ratio of the ith charging characteristic value to the ith initial charging characteristic value. The reduction rate of the ith discharge characteristic value may be a ratio of the ith discharge characteristic value to the ith initial discharge characteristic value.
[98]
For example, when n is 2, Equation 1 may be expressed as Equation 2 below.
[99]
[Equation 2]
[100]

[101]
The control unit 120 uses the first degradation factor F deg determined in step S630 as an index to determine the degree of degradation of the battery B from the second data table in which the correspondence between the first degradation factor and the degree of degradation is recorded. do.
[102]
The second data table may be previously stored in the memory unit 130 . As the hysteresis characteristic of the battery B becomes stronger, each of the first to nth main difference values ​​tends to increase. Accordingly, in the second data table, a relatively large first degradation factor may be associated with a relatively large degree of degradation.
[103]
7 is a flowchart exemplarily showing a method for determining a deterioration degree of a battery according to a third embodiment of the present invention. The method of FIG. 7 may be utilized to determine the degree of degradation of the battery B in which at least one peak appears in the differential capacity curve.
[104]
1 to 4 and 7 , in step S702, the controller 120 senses first sensing information indicating the voltage and current of the battery B during the first period charged with the first constant current. It is obtained from (110).
[105]
In step S704 , the control unit 120 acquires, from the sensing unit 110 , second sensing information indicating the voltage and current of the battery B during the second period to be discharged with the second constant current.
[106]
In step S712 , the controller 120 determines a first differential capacity curve of the battery B based on the first sensing information. For example, the first differential capacitance curve may be the differential capacitance curve 401 of FIG. 4 .
[107]
In step S714 , the controller 120 determines a second differential capacity curve of the battery B based on the second sensing information. For example, the second differential capacitance curve may be the differential capacitance curve 402 of FIG. 4 .
[108]
In step S722 , the controller 120 detects a charging feature point (eg, P CD_2 ) from the first differential capacity curve . The charging feature point (eg, P CD_2 ) may be a peak located in a predetermined order based on the power storage amount among all the peaks of the first differential capacity curve.
[109]
In step S724 , the controller 120 detects a discharge characteristic point (eg, P DD_2 ) from the second differential capacity curve . The discharge characteristic point (eg, P DD_2 ) may be a peak located in the predetermined order based on the amount of power storage among all the peaks of the second differential capacity curve.
[110]
In step S730, control unit 120, a charging characteristic value (for example, V CD_2 ) and the initial charge characteristic value (for example, V CI_2 absolute value of the difference value of the difference between the first sub) (e, │V CD_2 - V CI_2 │) and the second sub-difference value (eg, │V DD_2 - V DI_2 │) that is the absolute value of the difference between the discharge characteristic value (eg, V DD_2 ) and the initial discharge characteristic value (eg, V DI_2 ) , the battery Determine the degree of degeneration in (B).
[111]
The initial charging characteristic value (eg, V CI_2 ) may be a voltage value of a peak (eg, P CI_2 ) positioned in the predetermined order in the differential capacity curve 301 . The initial discharge characteristic value (eg, V DI_2 ) may be a voltage value of a peak (eg, P DI_2 ) positioned in the predetermined order in the differential capacity curve 302 .
[112]
Charging characteristic value (for example, V CD_2 ) charging characteristic point (for example, V CD_2 a voltage value), the discharge characteristic value (for example, V DD_2 ) is the discharge characteristic point (for example, V DD_2 a voltage value). The controller 120 may determine a sum of the product of the first sub-difference value and the first transform coefficient and the product of the second sub-difference value and the second transform coefficient as the second degradation factor. The first transform coefficient and the second transform coefficient are based on the fact that the first sub-difference value and the second sub-difference value may be different from each other when the deterioration degree of the battery B is the same. A value for adjusting the relative magnitude between the second sub-difference values. The first conversion coefficient may be a positive number predetermined based on a correspondence relationship between the degradation degree of the battery B and the first sub-difference value. The second conversion coefficient may be a positive number predetermined based on a correspondence relationship between the degradation degree of the battery B and the second sub-difference value.
[113]
The controller 120 uses the second degradation factor determined in step S730 as an index to determine the degradation degree of the battery B from the third data table in which the correspondence between the second degradation factor and the degradation degree is recorded.
[114]
The third data table may be previously stored in the memory unit 130 . As the hysteresis characteristic of the battery B becomes stronger, the first sub-difference value and the second sub-difference value tend to increase at different rates. Accordingly, in the third data table, a relatively large second degradation factor is associated with a relatively large degree of degradation.
[115]
On the other hand, when the ratio of the other to any one of the first sub-difference value (eg, │V CD_2 - V CI_2 │) and the second sub-difference value (eg, │V DD_2 - V DI_2 │) exceeds a predetermined range , the controller 120 may determine that the battery B is abnormal. In this case, instead of determining the degree of deterioration of the battery B, the controller 120 may output a message for notifying the user that the battery B is abnormal using the interface unit 140 .
[116]
When the deterioration degree of the battery B is determined according to at least one of the first to third embodiments, the controller 120 sends a message for notifying the user of the deterioration degree of the battery B to the interface unit 140 . can be used to print.
[117]
The embodiment of the present invention described above is not implemented only through the apparatus and method, and may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium in which the program is recorded. The implementation can be easily implemented by those skilled in the art to which the present invention pertains from the description of the above-described embodiments.
[118]
In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of ​​the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.
[119]
In addition, since the present invention described above is capable of various substitutions, modifications and changes within the scope that does not depart from the technical spirit of the present invention for those of ordinary skill in the art to which the present invention pertains, the above-described embodiments and attachments It is not limited by the illustrated drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications may be made.

WE CLAIMS

An apparatus for determining a degree of degradation of a battery, comprising: generating first sensing information representing a voltage and current of the battery during a first period in which the battery is charged with a first constant current, and discharging the battery with a second constant current a sensing unit configured to generate second sensing information indicating voltage and current of the battery for a second period; and a control unit operatively coupled to the sensing unit, wherein the control unit is configured to determine a first differential capacity curve of the battery based on the first sensing information, and from the first differential capacity curve configured to detect a first charging characteristic, and based on the second sensing information, to determine a second differential capacity curve of the battery, and configured to detect a first discharge characteristic from the second differential capacity curve; and determine the degree of degradation of the battery based on one charging characteristic value and a first discharging characteristic value, wherein the first charging characteristic value is a voltage value of the first charging characteristic value, and the first discharging characteristic value is , which is the voltage value of the first discharge characteristic point.
[Claim 2]
The second differential capacitance according to claim 1, wherein the control unit is configured to determine, as the first charging feature point, a peak located in a first predetermined order among a predetermined number of peaks located in the first differential capacity curve; and determine, as the first discharge characteristic point, a peak located in the first predetermined order among a predetermined number of peaks located on the curve.
[Claim 3]
3. The apparatus of claim 2, wherein the control unit is configured to determine a first primary difference value representing an absolute value of a difference between the first charging characteristic value and the first discharging characteristic value.
[Claim 4]
The method of claim 3, wherein the control unit determines the degree of degradation of the battery from a first data table in which a correspondence relationship between the first major difference value and the degree of degradation is recorded, using the first major difference value as an index. configured device.
[Claim 5]
The method of claim 2, wherein the control unit is configured to determine, as a second charging feature, a peak located in a second predetermined order among the predetermined number of peaks located on the first differential capacity curve when the predetermined number is 2 or more. and determining, as a second discharge characteristic point, a peak located in the second predetermined order among the predetermined number of peaks located on the second differential capacity curve, a second charge characteristic value and a second discharge characteristic value and determine a second main difference value representing an absolute value of the difference between the two main difference values, wherein the second charging characteristic value is a voltage value of the second charging characteristic point, and the second discharge characteristic value is a voltage value of the second discharge characteristic point. in device.
[Claim 6]
The method of claim 5, wherein the control unit is configured to determine the first degradation factor using the following equation when the predetermined number is 2, [Equation] ΔV i is the i-th main difference value, α i is an i-th predetermined weight, F deg is the first degradation factor, and using the first degradation factor as an index, the battery is obtained from a second data table in which a correspondence relationship between the first degradation factor and the degree of degradation is recorded. A device configured to determine the degree of degeneration of
[Claim 7]
The method of claim 1, wherein the control unit is configured to determine a first sub-difference value representing an absolute value of a difference between the first charging characteristic value and a first initial charging characteristic value, the first discharging characteristic value and the first charging characteristic value an apparatus configured to determine a second sub-difference value representing an absolute value of a difference between initial discharge characteristic values, and to determine a degree of degradation of the battery based on the first sub-difference value and the second sub-difference value .
[Claim 8]
The method of claim 7, wherein the control unit is configured to determine, as a second degradation factor, a sum of a product of the first sub-difference value and a first transform coefficient and a product of the second sub-difference value and a second transform coefficient; and determine the degree of degradation of the battery from a third data table in which a correspondence relationship between the second degradation factor and the degree of degradation is recorded, using the second degradation factor as an index.
[Claim 9]
A battery pack comprising the device according to claim 1 .
[Claim 10]
A method for determining a degree of degradation of a battery, the method comprising: acquiring first sensing information indicating a voltage and a current of the battery during a first period in which the battery is charged with a first constant current; acquiring second sensing information indicating the voltage and current of the battery during a second period in which the battery is discharged with a second constant current; determining a first differential capacity curve of the battery based on the first sensing information; determining a second differential capacity curve of the battery based on the second sensing information; detecting a first charging characteristic point from the first differential capacity curve; detecting a first discharge characteristic point from the second differential capacity curve; and determining the degree of degradation of the battery based on a first charging characteristic value and a first discharging characteristic value, wherein the first charging characteristic value is a voltage value of the first charging characteristic point, and the first The discharge characteristic value is a voltage value of the first discharge characteristic point.
[Claim 11]
11. The method of claim 10, wherein determining the degradation degree of the battery comprises: determining a first main difference value representing an absolute value of a difference between the first charging characteristic value and the first discharging characteristic value; and determining the deterioration degree of the battery from a first data table in which a correspondence relationship between the first main difference value and the deterioration degree is recorded by using the first main difference value as an index.