KR20240025909A - Apparatus and method for estimating state of charge of battery - Google Patents

Abstract

A battery SOC estimation device according to an embodiment of the present invention includes a charge/discharge unit configured to charge and discharge a battery according to a control signal; a measuring unit configured to measure the voltage of the battery during the charging and discharging process of the battery; And a control unit configured to transmit the control signal to the charging/discharging unit and estimate the SOC of the battery based on a preset reference profile at an SOC where the amount of voltage change before and after the idle period when charging the battery is greater than or equal to a preset threshold. You can.

Description

Battery SOC estimation device and method {APPARATUS AND METHOD FOR ESTIMATING STATE OF CHARGE OF BATTERY}

The present invention relates to a battery SOC estimating device and method, and more specifically, to a battery SOC estimating device and method for estimating the SOC of a battery.

Recently, as the demand for portable electronic products such as laptops, video cameras, and portable phones has rapidly increased, and as the development of electric vehicles, energy storage batteries, robots, and satellites has begun, the need for high-performance batteries capable of repeated charging and discharging has increased. Research is actively underway.

Currently commercialized batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium batteries. Among these, lithium batteries have almost no memory effect compared to nickel-based batteries, so they can be freely charged and discharged, and have a very high self-discharge rate. It is attracting attention due to its low and high energy density.

In general, the SOC of a battery can be estimated from a current integration method that integrates the charge/discharge current amount or from OCV measured by considering the correspondence between SOC (State of charge) and OCV (Open circuit voltage). In addition, a method of estimating SOC using the EKF (Extended Kalman Filter) of the battery model using the voltage behavior of the battery is also used.

Meanwhile, since NCM batteries using nickel/manganese/cobalt have a high risk of explosion, LFP (lithium/phosphate/iron) batteries, which are relatively inexpensive and have a low risk of fire, are attracting attention. However, unlike NCM batteries, these LFP batteries have many flat sections in the OCV table, so there are limitations in estimating SOC using the existing SOC estimation method of NCM batteries. Here, the flat section is a section where the rate of change of voltage (specifically, OCV) with respect to SOC is less than the reference value, and can be expressed as a plateau section, plat section, and flat section.

The present invention was made to solve the above problems, and its purpose is to provide a battery SOC estimation device and method that can more accurately estimate the SOC of the battery using the amount of voltage change in the rest period when charging an LFP battery. Do it as

Other objects and advantages of the present invention can be understood from the following description and will be more clearly understood by practicing 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.

A battery SOC estimation device according to an aspect of the present invention includes a charge/discharge unit configured to charge and discharge a battery according to a control signal; a measuring unit configured to measure the voltage of the battery during the charging and discharging process of the battery; And a control unit configured to transmit the control signal to the charging/discharging unit and estimate the SOC of the battery based on a preset reference profile at an SOC where the amount of voltage change before and after the idle period when charging the battery is greater than or equal to a preset threshold. You can.

In one embodiment, the control unit determines the SOC of the battery based on the reference profile for a SOC belonging to a predetermined SOC section among at least one SOC whose voltage change before and after the idle section when charging the battery is greater than or equal to a preset threshold. It can be configured to estimate.

In one embodiment, the control unit may be configured to estimate the SOC of the battery based on the reference profile at the SOC with the largest voltage change among the at least one SOC belonging to the predetermined SOC section.

In one embodiment, the predetermined SOC section may be configured so that the rate of change of voltage with respect to the SOC is less than the reference value in the sections before and after the SOC section.

In one embodiment, the predetermined SOC section may belong to a SOC section of SOC 50% or more, and the before and after sections may be comprised of sections where the rate of change of voltage with respect to the SOC is less than a reference value.

In one embodiment, the threshold may be a value set differently depending on the SOC section of the battery.

In one embodiment, the measuring unit may be configured to further measure the current of the battery during the charging and discharging process.

In one embodiment, the control unit may be configured to estimate the SOC for the battery using a value that integrates the current of the battery during the charging and discharging process, and to correct the estimated SOC based on the reference profile. .

In one embodiment, the control unit may be configured to transmit a control signal that causes the battery to perform step charging.

In one embodiment, the control unit may be configured to transmit a control signal that performs the step charging in such a way that the battery performs charging in predetermined SOC units and has a rest period for a certain period of time.

In one embodiment, the control unit sets a charging set in which the battery performs charging in the predetermined SOC unit and then has an idle period for the predetermined time, and the battery is charged in the charging set unit. It may be configured to transmit a control signal to the charging/discharging unit to perform.

In one embodiment, the control unit may be configured to estimate the SOC of the battery based on the reference profile for the SOC corresponding to the largest charging set among a plurality of charging sets in which the resting voltage change is greater than or equal to the preset threshold. You can.

A battery pack according to another aspect of the present invention may include a battery SOC estimation device according to an aspect of the present invention.

A battery SOC estimation method according to another aspect of the present invention includes a charging and discharging step of charging and discharging a battery according to a control signal; A voltage measurement step of measuring the voltage of the battery during the charging and discharging process of the battery; and a SOC estimation step of estimating the SOC of the battery based on a preset reference profile at an SOC in which the amount of voltage change before and after the rest period when charging the battery is greater than or equal to a preset threshold.

According to one aspect of the present invention, the SOC of the battery can be more accurately estimated using the amount of voltage change in the idle section when charging the LFP battery. In particular, the present invention has the advantage of being able to accurately estimate the SOC of the battery even in sections where the OCV is flat.

The 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.

The following drawings attached to this specification serve to further understand the technical idea of the present invention along with the detailed description of the invention described later, and therefore the present invention should not be construed as limited to the matters described in such drawings.
1 is a diagram schematically showing a battery SOC estimation device according to an embodiment of the present invention.
Figure 2 is a diagram illustrating an example in which a battery SOC estimation device calculates the amount of voltage change of a battery according to an embodiment of the present invention.
Figure 3 is a diagram illustrating an example in which a battery SOC estimating device estimates the SOC of a battery according to an embodiment of the present invention.
4 to 6 are diagrams illustrating another embodiment in which a battery SOC estimating device estimates the SOC of a battery according to an embodiment of the present invention.
Figure 7 is a diagram schematically showing an exemplary configuration of a battery pack according to another embodiment of the present invention.
Figure 8 is a diagram schematically showing a battery SOC estimation method according to another embodiment of the present invention.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing this application, various alternatives are available to replace them. It should be understood that equivalents and variations may exist.

Additionally, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

Terms containing ordinal numbers, 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 limit the components by such terms.

Throughout the specification, when a part is said to “include” a certain element, this means that it does not exclude other elements, but may further include other elements, unless specifically stated to the contrary.

Additionally, throughout the specification, when a part is said to be "connected" to another part, this refers not only to the case where it is "directly connected" but also to the case where it is "indirectly connected" with another element in between. Includes.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a diagram schematically showing a battery SOC estimation device 100 according to an embodiment of the present invention.

Referring to FIG. 1, the battery SOC estimation device 100 according to an embodiment of the present invention may include a charge/discharge unit 110, a measurement unit 120, and a control unit 130.

The charge/discharge unit 110 may be configured to receive a control signal from the control unit 130 to charge and discharge the battery.

For example, the charging/discharging unit 110 may be connected to the control unit 130 to communicate via wired and/or wireless communication. Additionally, the charge/discharge unit 110 may receive a control signal including C-rate information and charge/discharge start/end information from the control unit 130.

Specifically, the initial value of C-rate (Current-rate) information included in the control signal may be set directly by the control unit 130 or by user input depending on the specifications of the battery.

The charge/discharge unit 110 may be configured to charge and discharge the battery according to a control signal.

Here, the battery has a negative terminal and a positive terminal and refers to an independent cell that is physically separable. As an example, a lithium ion battery or a lithium polymer battery may be considered a battery. Additionally, a battery may refer to a battery module in which a plurality of cells are connected in series and/or parallel. Hereinafter, for convenience of explanation, the battery will be described as meaning one independent cell.

Specifically, the charge/discharge unit 110 can read C-rate information included in the control signal and charge or discharge the battery at the corresponding C-rate.

For example, when the C-rate is preset to 1C, the charge/discharge unit 110 can charge the battery at a C-rate of 1C or discharge the battery at a C-rate of 1C.

However, note that the value of C-rate information that can be included in the control signal is not particularly limited. That is, the value of C-rate information can be set to 0.05C or higher. Preferably, the value of C-rate information can be set to 0.05C or more and 3C or less.

The measuring unit 120 may be configured to measure the voltage of the battery during the battery charging and discharging process.

Specifically, the measuring unit 120 may be connected to the positive and negative terminals of the battery. In addition, the measuring unit 120 can measure the voltage of the battery by measuring the positive and negative voltages of the battery, respectively, and calculating the difference between the positive and negative voltages. That is, the measuring unit 120 can measure the terminal voltage of the battery during the battery charging and discharging process.

Additionally, the measuring unit 120 may be configured to further measure the current of the battery during the battery charging and discharging process.

The control unit 130 may be configured to transmit a control signal to charge and discharge the battery to the charge/discharge unit 110. As described above, the control unit 130 may generate a control signal including C-rate information and transmit the generated control signal to the charging/discharging unit 110.

The control unit 130 may be configured to estimate the SOC of the battery based on a preset reference profile at an SOC where the amount of voltage change before and after the idle period when charging the battery is greater than or equal to a preset threshold.

Here, the threshold may be a value set differently depending on the SOC section of the battery. Preferably, the threshold may be a value determined experimentally depending on the level of SOC. Specifically, the threshold may be set larger as the SOC level increases, and may be set lower as the SOC level becomes lower. For example, the first threshold value set for the first SOC section where SOC is 10% to 40% and the second threshold value set for the second SOC section where SOC is 50% to 70% may be different from each other. Here, the first threshold may be less than the second threshold.

Specifically, the control unit 130 can estimate the SOC for the battery using the accumulated value of the battery current during the charging and discharging process. That is, the control unit 130 may first estimate the SOC of the battery using a current integration method based on the current value of the battery measured by the measurement unit 120. In addition, the control unit 130 may be configured to correct the estimated SOC (SOC estimated using the current integration method) based on the reference profile if the amount of voltage change before and after the idle period is greater than or equal to a preset threshold. After the SOC is estimated, the control unit 130 may continue to estimate the SOC of the battery using a current integration method based on the estimated SOC.

The battery SOC estimation device according to an embodiment of the present invention can more accurately estimate the SOC of the battery by correcting the SOC of the battery based on the comparison result between the voltage change before and after the idle period and the threshold value. For example, even for LFP cells, the SOC can be corrected when the amount of voltage change before and after the idle period is greater than or equal to the threshold. Therefore, there is an advantage that the SOC of the LFP cell can be estimated more accurately based on the corrected SOC.

Meanwhile, the control unit 130 provided in the battery SOC estimation device 100 according to an embodiment of the present invention uses a processor known in the art, an application-specific integrated circuit (ASIC), to execute various control logics performed in the present invention. ), other chipsets, logic circuits, registers, communication modems, data processing devices, etc. may optionally be included. Additionally, when the control logic is implemented as software, the control unit 130 may be implemented as a set of program modules. At this time, the program module is stored in memory and can be executed by the control unit 130. The memory may be inside or outside the control unit 130 and may be connected to the control unit through various well-known means.

Additionally, the battery SOC estimation device 100 according to an embodiment of the present invention may further include a storage unit 140. The storage unit 140 stores data or programs necessary for each component of the battery SOC estimation device 100 to perform operations and functions, or data generated in the process of performing operations and functions, etc. You can save it. There is no particular limitation on the type of the storage unit 140 as long as it is a known information storage means that is known to be capable of recording, erasing, updating, and reading data. As an example, information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. Additionally, the storage unit 140 may store program codes in which processes executable by the control unit 130 are defined.

The control unit 130 may estimate the SOC of the battery based on a reference profile for a SOC belonging to a predetermined SOC section among at least one SOC whose voltage change before and after the idle section when charging the battery is greater than or equal to a preset threshold.

Specifically, a predetermined SOC section may be configured so that the rate of change of voltage with respect to SOC is less than the reference value in the sections before and after the SOC section. For example, the SOC section before and after a certain SOC section may be a flat section of an LFP cell.

For example, assume that a predetermined SOC section belongs to an SOC section with SOC 50% or more, and that the before and after sections are set as sections where the rate of change of voltage with respect to the SOC is less than the reference value. Specifically, it is assumed that the predetermined SOC section is set to be a mid-level SOC section of SOC 50% to 70%. The control unit 130 may estimate the SOC of the battery based on the reference profile in a mid-level SOC section where the SOC is 50% to 70%. In this case, the previous SOC section containing 49% of SOC may be a flat section, and the subsequent SOC section containing 71% of SOC may be a flat section.

As another example, assume that a predetermined SOC section belongs to an SOC section with SOC less than 50%, and that the before and after sections are set as sections where the rate of change of voltage with respect to the SOC is less than the reference value. Specifically, it is assumed that the predetermined SOC section is set as a low-level SOC section of 10% to 20% of SOC. The control unit 130 may estimate the SOC of the battery based on a reference profile for a low-level SOC where the SOC is 10% or more and 20% or less. In this case, the previous SOC section containing 9% of SOC may be a flat section, and the subsequent SOC section containing 21% of SOC may be a flat section. In other words, a predetermined SOC section can be set only when both the previous SOC section and the subsequent SOC section are flat sections, and if the previous SOC section and/or the subsequent SOC section are non-flat sections, it is not set as a predetermined SOC section. It may not be possible. The predetermined SOC section can be confirmed through the correspondence between voltage and SOC during the charging and discharging process of the battery, and the predetermined SOC section may change as the battery deteriorates.

That is, the battery SOC estimation device according to an embodiment of the present invention can correct the SOC of the battery in a non-flat section (predetermined SOC section) between two flat sections. Specifically, the SOC estimated according to the current integration method in the corresponding non-flat section can be corrected based on a preset reference profile. Therefore, since the SOC of the battery can be appropriately corrected, the SOC of the LFP cell can be more accurately estimated in the flat section and the non-flat section according to the corrected SOC.

The control unit 130 may transmit a control signal to the charge/discharge unit 110 to cause the battery to perform step charging.

For example, the control unit 130 performs step charging in such a way that the battery is charged in a predetermined SOC unit (e.g., SOC 3% unit) and has a rest period for a certain period of time (e.g., 5 minutes). A signal can be transmitted.

Specifically, the control unit 130 may set one charging set in which the battery performs charging in a predetermined SOC unit and then has a rest period for a certain period of time. In this case, the control unit 130 may transmit a control signal to the charging/discharging unit 110 to cause the battery to perform charging in units of charging sets.

Additionally, the control unit 130 may estimate the SOC of the battery based on the reference profile for the SOC corresponding to the charging set with the largest change in resting voltage among the plurality of charging sets, which is greater than or equal to a preset threshold.

In this way, the battery SOC estimation device 100 according to an embodiment of the present invention can more accurately estimate the SOC of the battery using the amount of voltage change in the idle section when charging the LFP battery. In particular, the battery SOC estimation device 100 according to an embodiment of the present invention has the advantage of being able to accurately estimate the SOC of the battery even in the flat section of the LPF cell.

Figure 2 is a diagram illustrating an example in which a battery SOC estimation device calculates the amount of voltage change of a battery according to an embodiment of the present invention.

In FIG. 2, the control unit 130 of the battery SOC estimation device 100 according to an embodiment of the present invention may cause the battery to perform step charging. For example, the control unit 130 may charge the battery every 3% of the SOC and have a rest period every 5 minutes. Additionally, the control unit 130 may repeat N sets of these charging and resting processes as one charging set.

For example, in the embodiment of Figure 2, the charging set may be repeated when SOC is 58%, 61%, 64%, 67%, and 70%.

Additionally, the control unit 130 can measure and record the voltage of the battery after the idle period for each charging set ends. Based on this, the control unit 130 can calculate the amount of voltage change before and after the idle period for each charging set. That is, the control unit 130 can calculate the amount of voltage change before and after the idle period as a total of N values when the battery charging set is repeated N times.

Unlike existing NCM batteries, LFP batteries have many sections where the OCV is flat, so even if the error in the estimated OCV voltage is small, a large error may occur when estimating SOC. However, by using the amount of change in voltage of the battery, as in the battery SOC estimation device 100 according to an embodiment of the present invention, a section in which the voltage change changes rapidly locally can be extracted even within a flat section. Therefore, SOC can be estimated more accurately by using a SOC estimation method such as a current integration method for this section.

Additionally, the control unit 130 may record the accumulated current amount after each charging set is terminated. That is, the control unit 130 can calculate the accumulated current amount as a total of N values when the battery charging set is repeated N times.

Figure 3 is a diagram illustrating an example in which a battery SOC estimating device estimates the SOC of a battery according to an embodiment of the present invention.

Referring to FIG. 3, when the charging set of the battery described in FIG. 2 is repeated N times, the control unit 130 of the battery SOC estimation device 100 according to an embodiment of the present invention The SOC point with the largest voltage change can be selected as the correction target. In the embodiment of FIG. 3, the SOC profile may be a profile representing the correspondence between the SOC of the battery and the charge/discharge time obtained during the charging and discharging process of the battery. Additionally, the reference profile may be a profile in which the correspondence between SOC and charge/discharge time is preset.

Additionally, the control unit 130 may select as a correction target an SOC point in which the voltage change before and after the idle period among the N charging sets is greater than a preset threshold. Here, the threshold may be a value set differently depending on the SOC section of the battery, as described above. For example, the threshold may be a value determined experimentally according to the level of SOC.

After all charging sets of the battery are completed, the control unit 130 may correct the SOC value using the cumulative accumulated value recorded for each charging set for the SOC point selected as the correction target. Meanwhile, here, the correction method using the cumulative accumulated value may be included in the reference profile described in FIG. 1.

As shown in FIG. 3, the control unit 130 performs SOC correction using the current integration value (c) at the SOC point (SOC 61%) selected as the correction target to adjust the SOC to be very close to the actual SOC value. can be estimated.

For example, in the embodiment of Figures 2 and 3, the charging set may be repeated when SOC is 58%, 61%, 64%, 67%, and 70%. In the embodiment of FIG. 2, since the amount of voltage change is greatest at SOC 61%, the control unit 130 can correct the SOC at time t corresponding to SOC 61% to k%. In addition, the control unit 130 can estimate the SOC at 8000 s, when five step charges are completed, using the current loss method based on SOC k%. That is, the SOC at 8000 s can be estimated by adding the current integration value (c) based on the SOC k% at time t.

In this way, the battery SOC estimation device 100 according to an embodiment of the present invention extracts the point where the voltage change is greatest during the battery charging process and corrects this by using a SOC estimation method using a reference profile such as a current integration method. By performing , there is an advantage of being able to estimate SOC more precisely for LFP batteries.

4 to 6 are diagrams illustrating another embodiment in which a battery SOC estimating device estimates the SOC of a battery according to an embodiment of the present invention.

Specifically, FIGS. 4 to 6 are diagrams illustrating an embodiment of estimating SOC using first to third batteries in which the error between the reference profile and the SOC profile is preset to 10%. In common, the first to third batteries were charged from SOC 30% to 0.3C at a temperature of 25°C. Step charging was set to have a 5-minute pause every 3% of SOC.

In addition, the first battery started 7 step charges at SOC 52%, the 2nd battery started 7 step charges at SOC 53%, and the 3rd battery started 7 step charges at SOC 54%.

In the embodiment of FIG. 4, the starting SOC of step charging may be 52%, and the ending SOC of step charging may be 73%. After SOC 73%, the battery's SOC error can be reduced from 10% to about 1.8%.

In the embodiment of Figure 5, the starting SOC of step charging may be 53%, and the ending SOC of step charging may be 74%. After SOC 74%, the battery's SOC error can be reduced from 10% to approximately 0%.

In the embodiment of FIG. 6, the starting SOC of step charging may be 54%, and the ending SOC of step charging may be 75%. After SOC 75%, the battery's SOC error can be reduced from 10% to about 0.8%.

Referring to FIGS. 4 to 6, the battery SOC estimation device 100 according to an embodiment of the present invention performs correction based on a reference profile for SOC points where the voltage change amount is large before and after the idle period when charging the battery, It can be seen that SOC can be estimated to have a value very close to the actual SOC value.

The battery SOC estimation device 100 according to the present invention can be applied to a Battery Management System (BMS). That is, the BMS according to the present invention may include the battery SOC estimation device 100 described above. In this configuration, at least some of the components of the battery SOC estimation device 100 may be implemented by supplementing or adding functions included in the conventional BMS. For example, the charge/discharge unit 110, measurement unit 120, control unit 130, and storage unit 140 of the battery SOC estimation device 100 may be implemented as components of a BMS.

Additionally, the battery SOC estimation device 100 according to the present invention may be provided in the battery pack 1. That is, the battery pack 1 according to the present invention may include the above-described battery SOC estimation device 100 and one or more battery cells. Additionally, the battery pack 1 may further include electrical components (relays, fuses, etc.) and a case.

Figure 7 is a diagram schematically showing an exemplary configuration of a battery pack according to another embodiment of the present invention.

Referring to Figure 7, the positive electrode of the battery (B) may be connected to the positive terminal (P+) of the battery pack (1), and the negative electrode of the battery (B) may be connected to the negative terminal (P-) of the battery pack (1). there is.

The measuring unit 120 is connected between the positive terminal of the battery (B) and the positive terminal (P+) of the battery pack (1) through the first sensing line (SL1), and the positive terminal (P+) of the battery (B) through the second sensing line (SL2). ) can be connected between the negative electrode of the battery pack (1) and the negative terminal (P-) of the battery pack (1). Accordingly, the measurement unit 120 can measure the voltage of the battery B through the first sensing line SL1 and the second sensing line SL2.

In addition, the measuring unit 120 is connected to the current measuring element (A) provided in the charge/discharge path (high current path) of the battery (B) through the third sensing line (SL3), and measures the charge/discharge current of the battery (B). can be measured. Here, the current measuring element (A) may be an ammeter and/or a shunt resistor.

One end of the charge/discharge unit 110 is connected between the positive electrode of the battery (B) and the positive terminal (P+) of the battery pack (1), and the other end is connected between the negative electrode of the battery (B) and the negative terminal (P+) of the battery pack (1). -) can be connected between. Additionally, the charge/discharge unit 110 may charge and discharge the battery B based on the C-rate information included in the control signal received from the control unit 130.

Figure 8 is a diagram schematically showing a battery SOC estimation method according to another embodiment of the present invention.

Preferably, each step of the battery SOC estimation method may be performed by the battery SOC estimation device 100. Note that below, for convenience of explanation, content that overlaps with the content described above will be briefly described or omitted.

Referring to FIG. 8, the battery SOC estimation method according to another embodiment of the present invention may include a charging and discharging step (S100), a voltage measurement step (S200), and a SOC estimation step (S300).

The charging and discharging step (S100) is a step of charging and discharging the battery at the C-rate included in the control signal, and may be performed by the charging and discharging unit 110.

For example, the charge/discharge unit 110 may receive a control signal including C-rate information and charge/discharge start/end information from the control unit 130. Additionally, the charge/discharge unit 110 can read the C-rate information included in the control signal and charge or discharge the battery B at the corresponding C-rate.

The voltage measurement step S200 is a step of measuring the voltage of the battery B during the charging and discharging process of the battery B, and may be performed by the measuring unit 120.

The SOC estimation step (S300) is a step of estimating the SOC of the battery based on a preset reference profile at the SOC where the voltage change before and after the idle period when charging the battery is greater than or equal to a preset threshold, and can be performed by the control unit 130. there is.

Here, the threshold may be a value set differently depending on the SOC section of the battery. For example, the threshold may be a value determined experimentally according to the level of SOC.

Specifically, the control unit 130 may estimate the SOC of the battery based on a reference profile for a SOC belonging to a predetermined SOC section among at least one SOC whose voltage change before and after the idle section when charging the battery is greater than or equal to a preset threshold. there is. Then, the control unit 130 can subsequently estimate the SOC of the battery using a current integration method based on the estimated SOC.

In this way, the battery SOC estimation method according to an embodiment of the present invention can more accurately estimate the SOC of the battery by using the amount of voltage change in the idle section when charging the LFP battery. In particular, the battery SOC estimation method according to an embodiment of the present invention has the advantage of accurately estimating the SOC of the battery even in sections where the OCV is flat.

The embodiments of the present invention described above are not only implemented through devices and methods, but may also be implemented through a program that realizes the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. The implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the description below will be understood by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalence of the patent claims.

In addition, the present invention described above is capable of various substitutions, modifications and changes without departing from the technical spirit of the present invention to those of ordinary skill in the technical field to which the present invention pertains. It is not limited by the drawings, and all or part of each embodiment can be selectively combined so that various modifications can be made.

1: Battery pack
100: Battery SOC estimation device
110: Charge/discharge unit
120: measuring unit
130: control unit
140: storage unit

Claims (13)

a charge/discharge unit configured to charge/discharge the battery according to a control signal;
a measuring unit configured to measure the voltage of the battery during the charging and discharging process of the battery; and
A control unit configured to transmit the control signal to the charging/discharging unit and estimate the SOC of the battery based on a preset reference profile at an SOC in which the amount of voltage change before and after the idle period when charging the battery is greater than or equal to a preset threshold. Features a battery SOC estimation device.
According to paragraph 1,
The control unit,
A battery characterized in that it is configured to estimate the SOC of the battery based on the reference profile for a SOC belonging to a predetermined SOC section among at least one SOC whose voltage change before and after the idle section when charging the battery is greater than or equal to a preset threshold. SOC estimator.
According to paragraph 2,
The control unit,
A battery SOC estimation device, characterized in that it is configured to estimate the SOC of the battery based on the reference profile at the SOC with the largest voltage change among the at least one SOC belonging to the predetermined SOC section.
According to paragraph 2,
The predetermined SOC section is,
A battery SOC estimation device characterized in that the rate of change of voltage with respect to SOC in the sections before and after the SOC section is less than the reference value.
According to paragraph 4,
The predetermined SOC section is,
A battery SOC estimation device, characterized in that it belongs to a SOC section of 50% or more of SOC, and the before and after sections are comprised of sections where the rate of change of voltage with respect to the SOC is less than a reference value.
According to paragraph 1,
The threshold is,
A battery SOC estimation device, characterized in that the value is set differently depending on the SOC section of the battery.
According to paragraph 1,
The measuring unit,
Configured to further measure the current of the battery during the charging and discharging process,
The control unit,
A battery SOC estimation device, characterized in that it is configured to estimate the SOC for the battery using a value that integrates the current of the battery during the charging and discharging process, and to correct the estimated SOC based on the reference profile.
According to paragraph 1,
The control unit,
A battery SOC estimation device, characterized in that it is configured to transmit a control signal that causes the battery to perform step charging.
According to clause 8,
The control unit,
A battery SOC estimation device characterized in that the battery performs charging in predetermined SOC units and transmits a control signal for performing the step charging in such a way that there is a rest period for a certain period of time.
According to clause 9,
The control unit,
After the battery performs charging in the predetermined SOC unit, setting the battery to have an idle period for the predetermined time as one charging set,
A battery SOC estimation device, characterized in that it is configured to transmit a control signal that causes the battery to perform charging in units of the charging set to the charging and discharging unit.
According to clause 10,
The control unit,
A battery SOC estimation device, characterized in that it is configured to estimate the SOC of the battery based on the reference profile for the SOC corresponding to the largest charging set among the plurality of charging sets in which the resting voltage change is greater than or equal to the preset threshold.
A battery pack including the battery SOC estimation device according to any one of claims 1 to 11.
A charging/discharging step of charging and discharging the battery according to a control signal;
A voltage measurement step of measuring the voltage of the battery during the charging and discharging process of the battery; and
A battery SOC estimation method comprising a SOC estimation step of estimating the SOC of the battery based on a preset reference profile at an SOC in which the amount of voltage change before and after the idle section when charging the battery is greater than or equal to a preset threshold.

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