Patent ID: 12210069

EMBODIMENTS OF THE PRE SENT DISCLOSURE

It should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation.

Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the disclosure, so it should be understood that other equivalents and modifications could be made thereto without departing from the scope of the disclosure.

Additionally, in describing the present disclosure, when it is deemed that a detailed description of relevant known elements or functions renders the key subject matter of the present disclosure ambiguous, the detailed description is omitted herein.

The terms including the ordinal number, such as “first,” “second,” and the like, may be used to distinguish one element from another among various elements, but not intended to limit the elements by the terms.

Throughout the specification, when a portion is referred to as “comprising” or “including” any element, it means that the portion may include other elements further, without excluding other elements, unless specifically stated otherwise.

In addition, throughout the specification, when a portion is referred to as being “connected” to another portion, it is not limited to the case that they are “directly connected”, but it also includes the case where they are “indirectly connected” with another element being interposed between them.

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

FIG.1is a diagram schematically showing a battery SOH estimating apparatus100according to an embodiment of the present disclosure.

Referring toFIG.1, the battery SOH estimating apparatus100may include a SOH estimating unit110, a SOC change calculating unit120, a weight calculating unit130, and a SOH correcting unit140.

The SOH estimating unit110may be configured to estimate a first SOH of a battery based on the measured voltage and current of the battery.

Here, the battery refers to one physically separable independent cell having a negative electrode terminal and a positive electrode terminal. For example, a lithium-ion battery or a lithium polymer cell may be regarded as the battery. In addition, the battery may refer to a battery module in which a plurality of cells are connected in series and/or in parallel. Hereinafter, for convenience of description, the battery will be described as meaning one independent cell.

The SOH estimating unit110may receive battery information about voltage, current, and temperature of the battery from the outside or may store the same in advance. Alternatively, the SOH estimating unit110may be configured to directly measure the voltage, current, and temperature of the battery.

In addition, the SOH estimating unit110may estimate a first SOH of the battery based on the voltage and current of the battery.

For example, the SOH estimating unit110may estimate the first SOH of the battery based on the change in capacity of the battery. The SOH estimating unit110may estimate a corresponding state of charge (SOC) from the voltage of the battery.

Here, an SOC profile representing a corresponding relationship between the voltage of the battery and the SOC may be preset, and the SOH estimating unit110may estimate the corresponding SOC from the voltage of the battery based on the SOC profile. Alternatively, the SOC profile may be preset to represent a corresponding relationship among the voltage, temperature, and SOC of the battery. In this case, the SOH estimating unit110may estimate the SOC corresponding to the voltage and temperature of the battery based on the SOC profile.

In addition, the SOH estimating unit110may calculate the capacity Q of the battery based on the estimated SOC and the battery current. Thereafter, the SOH estimating unit110may estimate the first SOH of the battery by calculating a ratio between a preset criterion capacity Qref and the calculated capacity Q for the battery. Here, the criterion capacity Qref is a preset value of the capacity of a battery in a BOL (Beginning of life) state and may be a capacity value corresponding to the OCV of the battery calculated by the SOH estimating unit110.

As another example, the SOH estimating unit110may estimate the first SOH of the battery based on the change in internal resistance of the battery. The SOH estimating unit110may estimate the internal resistance R of the battery from the voltage and current of the battery based on Ohm's law. In addition, the SOH estimating unit110may estimate the first SOH of the battery by calculating a ratio between a preset criterion resistance Rref and the calculated internal resistance R for the battery. Here, the criterion resistance Rref may be a preset value of the internal resistance of a battery in a BOL state.

The first SOH of the battery estimated by the SOH estimating unit110may be an SOH value based on the voltage and current of the battery measured in the present cycle.

The SOC change calculating unit120may be configured to calculate the SOC change region and the SOC change amount of the battery based on the measured voltage.

Specifically, the measured battery voltage may be plural. Preferably, the voltage of the battery may be measured during charging and/or discharging, and may include a start voltage and an end voltage. In addition, the SOC change calculating unit120may estimate the SOCs for the measured voltages (start voltage and end voltage) with reference to the SOC profile. The SOC change calculating unit120may calculate an SOC change region including the estimated SOCs. Also, the SOC change calculating unit120may calculate the SOC change amount by calculating a difference between the estimated SOCs.

For example, it is assumed that the measured battery voltages are V1 and V2, and the battery is charged from voltage V1 to voltage V2. The SOC change calculating unit120may estimate SOC1 corresponding to the voltage V1 and SOC2 corresponding to the voltage V2, respectively. The SOC change calculating unit120may calculate the SOC change region including SOC1 and SOC2 by setting the start SOC of the SOC change region to SOC1 and setting the end SOC of the SOC change region to SOC2. Also, the SOC change calculating unit120may calculate the SOC change amount by calculating the formula of “|SOC2−SOC1|”. Here, the SOC change amount may be expressed as ΔSOC, and may be calculated as a value of 0% or more and 100% or less.

The weight calculating unit130may be configured to calculate the weight based on a SOC region factor calculated by comparing the SOC change region with a preset criterion SOC region, a SOC change amount factor based on the SOC change amount, and a temperature factor based on the measured temperature of the battery.

Specifically, the weight calculating unit130may receive the temperature of the battery from the outside or store the same in advance. Alternatively, the weight calculating unit130may be configured to directly measure the temperature of the battery.

In addition, the weight calculating unit130may be configured to calculate the SOC region factor, the SOC change amount factor, and the temperature factor, respectively.

Here, the SOC region factor may be calculated according to whether the preset criterion SOC region and the SOC change region calculated by the SOC change calculating unit120overlap. For example, the weight calculating unit may calculate the SOC region factor according to whether at least a part of the SOC change region belongs to the criterion SOC region. A specific embodiment of calculating the SOC region factor will be described later in detail with reference toFIGS.3to5.

The SOC change amount factor is a factor calculated based on the SOC change amount calculated by the SOC change calculating unit120. For example, the weight calculating unit130may calculate the SOC change amount factor to be proportional to the SOC change amount. A specific embodiment of calculating the SOC change amount factor will be described in detail later with reference toFIG.6.

The temperature factor is a factor calculated based on the temperature of the battery. For example, the weight calculating unit130may calculate the temperature factor to be proportional to the temperature of the battery. A specific embodiment of calculating the temperature factor will be described later in detail with reference toFIG.7.

Also, the weight calculating unit130may be configured to calculate a weight based on the calculated SOC region factor, the calculated SOC change amount factor, and the calculated temperature factor. For example, the weight calculating unit130may calculate the weight by multiplying the SOC region factor, the SOC change amount factor, and the temperature factor. Here, the weight calculated by the weight calculating unit130may be set to have a value of 0 or more and 1 or less.

The SOH correcting unit140may be configured to correct the first SOH according to the calculated weight and a preset second SOH.

Specifically, the first SOH estimated based on the voltage and current by the SOH estimating unit110may be corrected based on the weight and the second SOH by the SOH correcting unit140.

FIG.2is a diagram schematically showing the SOH estimating process by the battery SOH estimating apparatus100according to an embodiment of the present disclosure.

Referring toFIG.2, the first SOH (SOH1) may be estimated based on the voltage and current of the battery. In addition, the first SOH (SOH1) may be corrected based on the second SOH (SOH2) and the weight (α), and the corrected first SOH (SOHMOD) may be calculated.

For example, the SOH correcting unit140may be configured to correct the first SOH using the following equation.
SOHMOD=(SOH1×α)+(SOH2×(1−α))  [Equation]

Here, SOHMODis the corrected first SOH, SOH1is the first SOH, SOH2is the second SOH, and α is a weight that may be 0 or more and 1 or less.

In the embodiment according to the above equation, the SOH correcting unit140may multiply the first SOH (SOH1) by the weight (α) and multiply the second SOH (SOH2) by the complement (1−α) for the weight (α). In addition, the SOH correcting unit140may calculate the corrected first SOH (SOHMOD) by adding the first SOH (SOH1) multiplied by weight (α) and the second SOH (SOH2) multiplied by the complement (1−α).

Referring toFIG.2further, the SOH estimating unit110may be configured to estimate the first SOH (SOH1) in the present cycle based on the voltage and current of the battery measured in the present cycle.

Specifically, the SOH estimating unit110may estimate the first SOH (SOH1) in the present cycle of the battery based on the voltage and current of the battery measured in each charging and discharging cycle of the battery. In addition, the SOH correcting unit140may be configured to correct the first SOH (SOH1) according to the weight (α) and the second SOH (SOW preset prior to the present cycle.

Also, referring toFIG.2, the second SOH (SOH2) may be the first SOH (SOHMOD) corrected in a previous cycle prior to the present cycle. That is, the corrected SOH (SOHMOD) calculated in the present cycle may be used as the second SOH (SOH2) in the next cycle.

The battery SOH estimating apparatus100according to an embodiment of the present disclosure has an advantage of more accurately estimating the battery SOH by considering not only the voltage, current, and SOC change amount of the battery but also the result of comparing the SOC change region of the battery and the criterion SOC region.

In addition, as the charging and discharging cycle of the battery progresses, the battery SOH estimating apparatus100may recursively estimate the SOH of the battery in the present cycle by considering the SOH (second SOH) of the battery estimated in the previous cycle and the weight calculated in the present cycle, and thus has an advantage of improving the SOH estimation accuracy of the battery.

Meanwhile, the SOH estimating unit110, the SOC change calculating unit120, the weight calculating unit130and the SOH correcting unit140included in the battery SOH estimating apparatus100may optionally include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, and a data processing device, and the like, known in the art to execute various control logics disclosed below.

In addition, the battery SOH estimating apparatus100may further include a storage unit150. The storage unit150may store data necessary for operation and function of each component of the battery SOH estimating apparatus100, data generated in the process of performing the operation or function, or the like. The storage unit150is not particularly limited in its kind as long as it is a known information storage means that can record, erase, update and read data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, and the like. In addition, the storage unit150may store program codes in which processes executable by the SOH estimating unit110, the SOC change calculating unit120, the weight calculating unit130and the SOH correcting unit140are defined.

Hereinafter, an embodiment in which the SOC region factor is calculated based on the SOC change region will be described.

The weight calculating unit130may be configured to calculate the SOC region factor according to whether at least a part of the SOC change region belongs to the criterion SOC region.

Preferably, the criterion SOC region may be configured to include a plurality of SOC regions. Accordingly, the weight calculating unit130may be configured to calculate the SOC region factor according to whether at least a part of the SOC change region belongs to each of the plurality of SOC regions.

FIG.3is a diagram schematically showing a negative electrode differential profile of the battery.FIG.4is a diagram schematically showing a positive electrode differential profile of the battery.

The differential profile ofFIGS.3and4is preset for a battery in a BOL state, and may be a differential profile representing a corresponding relationship between a differential voltage (dV/dSOC) for SOC and SOC. Specifically, the differential voltage may be an instantaneous change rate of the voltage (V) with respect to SOC. In addition, the differential profile may be expressed as an X-Y graph where X is SOC and Y is differential voltage (dV/dSOC).

In the negative electrode differential profile of the embodiment ofFIG.3, the intrinsic stress region of the negative electrode active material may appear in the SOC 0% to 40% region and the SOC 70% to 100% region. In addition, in the positive electrode differential profile of the embodiment ofFIG.4, the intrinsic stress region of the positive electrode active material may appear in the SOC 60% to 100% region.

Accordingly, the plurality of criterion SOC regions may be preset for each of the intrinsic stress region of the positive electrode active material and the intrinsic stress region of the negative electrode active material. For example, referring toFIGS.3and4, the first criterion SOC region A may be set to the SOC 0% to 40% region, the second criterion SOC region B may be set to the SOC 70% to 100% region, and the third criterion SOC region C may be set to the SOC 60% to 100% region.

However, in the embodiments ofFIGS.3and4, a total of three criterion SOC regions are set for the battery, but it should be noted that the number and size of the criterion SOC regions may vary according to the change in the active material composition of the battery.

In addition, the weight calculating unit130may be configured to calculate the number of SOC regions including at least a part of the SOC change regions among the plurality of SOC regions, and calculate the SOC region factor according to the calculated number.

FIG.5is a diagram schematically showing an example of a SOC region factor table set in the battery SOH estimating apparatus100according to an embodiment of the present disclosure.

Specifically, the SOC region factor table ofFIG.5may be a look-up table in which the SOC region factor is preset according to the number of SOC regions to which at least a part of the SOC change region of the battery belongs.

In the embodiment ofFIG.5, when at least a part of the SOC change region of the battery belongs to all of the first to third criterion SOC regions (A, B, C), the SOC region factor may be 1. For example, when the SOC change region of the battery is the SOC 30% to 80% region, the SOC region factor for the battery may be set to 1.

However, since the embodiment ofFIG.5is an embodiment having three preset criterion SOC regions, it should be noted that if the number of preset criterion SOC regions is changed, the SOC region factor may also be changed accordingly. For example, unlike the embodiment ofFIG.5, it is assumed that five criterion SOC regions are set. In this case, the number of SOC regions to which at least a part of the SOC change region belongs may be 5, 4, 3, 2, or 1. The SOC region factor may be set to 1 (the number of SOC regions belonging thereto is 5), 0.8 (the number of SOC regions belonging thereto is 4), 0.6 (the number of SOC regions belonging thereto is 3), 0.4 (the number of SOC regions belonging thereto is 2), and 0.2 (the number of SOC regions belonging thereto is 1).

In general, in the course of charging and discharging the battery, the degradation of the battery may be accelerated as the SOC of the battery is included in the intrinsic stress region of the positive electrode active material and/or the intrinsic stress region of the negative electrode active material. Therefore, the battery SOH estimating apparatus100according to an embodiment of the present disclosure has an advantage of calculating the SOC region factor in consideration of whether the degradation of the battery is accelerated according to the intrinsic stress region of the active material in order to more accurately estimate the battery SOH.

Hereinafter, an embodiment in which the SOC change amount factor is calculated based on the SOC change amount will be described.

The weight calculating unit130may be configured to calculate the SOC change amount factor to be proportional to the SOC change amount.

Here, the SOC change amount is a difference between the start SOC and the end SOC of the battery in one cycle, and is calculated as “|end SOC−start SOC|”, and may be expressed as ΔSOC.

FIG.6is a diagram schematically showing an example of a SOC change amount factor table set in the battery SOH estimating apparatus100according to an embodiment of the present disclosure.

Specifically, the SOC change amount factor table ofFIG.6may be a look-up table in which the SOC change amount factor is preset according to the SOC change amount of the battery.

In the embodiment ofFIG.6, the SOC change amount factor may be preset to be proportional to the SOC change amount (ΔSOC) of the battery. For example, the SOC change amount factor may be a value obtained by converting the SOC change amount (ΔSOC) to have a value of 0 to 1.

For example, as in the previous embodiment, it is assumed that the SOC change region of the battery is the SOC 30% to 80% region. In this case, the SOC change amount (ΔSOC) may be 50%. Accordingly, according to the SOC change amount factor table ofFIG.6, the SOC change amount factor for the battery may be set to 0.5.

Hereinafter, an embodiment in which the temperature factor is calculated based on the temperature of the battery will be described.

The weight calculating unit130may be configured to calculate the temperature factor according to a region to which the temperature of the battery belongs among a plurality of preset temperature regions.

Here, the battery temperature may be an average temperature or a maximum temperature of the battery in one cycle.

FIG.7is a diagram schematically showing an example of a temperature factor table set in a battery SOH estimating apparatus100according to an embodiment of the present disclosure.

Specifically, the temperature factor table ofFIG.7may be a look-up table in which the temperature factor is preset according to the temperature of the battery. In addition, the temperature factor may be preset to be proportional to the temperature of the battery. For example, the temperature factor may be a value obtained by converting the temperature of the battery to have a value of 0 to 1.

In the embodiment ofFIG.7, when the temperature of the battery is 25° C. or higher, the temperature factor may be set to 1. When the temperature of the battery is 15° C., the temperature factor may be set to 0.5. When the temperature of the battery is 0° C. or below, the temperature factor may be set to 0. In addition, it should be noted that the temperature factor for the temperature of the battery not recorded in the temperature factor table ofFIG.7may be calculated through interpolation of 0° C., 15° C., and 25° C.

For example, in each case where the temperature of the battery is 3° C., 6° C., 9° C., 12° C., 18° C., 21° C. or 24° C., the temperature factor may be 0.1, 0.2, 0.3, 0.4, 0.8 or 0.95, respectively.

The battery SOH estimating apparatus100according to an embodiment of the present disclosure may calculate a weight based on the temperature of the battery, the SOC change amount, and the SOC change region. That is, the battery SOH estimating apparatus100has an advantage of more accurately estimating the SOH of the battery by considering various factors (temperature, SOC change amount, and SOC change region) affecting the degradation of the battery. In particular, since the battery SOH estimating apparatus100considers the SOC change region factor caused by the intrinsic stress region of the active material, it has an advantage of reflecting the degradation acceleration factor of the battery in estimating the SOH of the battery.

The battery SOH estimating apparatus100according to the present disclosure may be applied to a battery management system (BMS). That is, the BMS according to the present disclosure may include the battery SOH estimating apparatus100described above. In this configuration, at least some of components of the battery SOH estimating apparatus100may be implemented by supplementing or adding functions of the components included in a conventional BMS. For example, the SOH estimating unit110, the SOC change calculating unit120, the weight calculating unit130, the SOH correcting unit140and the storage unit150of the battery SOH estimating apparatus100may be implemented as components of the BMS.

In addition, the battery SOH estimating apparatus100according to the present disclosure may be provided to a battery pack. That is, the battery pack according to the present disclosure may include the above-described battery SOH estimating apparatus100and one or more battery cells. In addition, the battery pack may further include electrical components (a relay, a fuse, and the like) and a case.

FIG.8is a diagram schematically showing an exemplary configuration of a battery pack according to another embodiment of the present disclosure.

The positive electrode terminal of the battery11may be connected to the positive electrode terminal P+ of the battery pack10, and the negative electrode terminal of the battery11may be connected to the negative electrode terminal P− of the battery pack10.

The measuring unit12may be connected to the first sensing line SL1, the second sensing line SL2, the third sensing line SL3and the fourth sensing line SL4.

Specifically, the measuring unit12may be connected to the positive electrode terminal of the battery11through the first sensing line SL1and may be connected to the negative electrode terminal of the battery11through the second sensing line SL2. The measuring unit12may measure the voltage of the battery11based on the voltage measured at each of the first sensing line SL1and the second sensing line SL2.

In addition, the measuring unit12may be connected to the current measuring unit13through the third sensing line SL3. For example, the current measuring unit13may be an ammeter or a shunt resistor capable of measuring the charging current and the discharging current of the battery11. The measuring unit12may calculate the charge amount by measuring the charging current of the battery11through the third sensing line SL3. Also, the measuring unit12may calculate the discharge amount by measuring the discharging current of the battery11through the third sensing line SL3.

Also, the measuring unit12may measure the temperature of the battery11through the fourth sensing line SL4.

The voltage, current and temperature of the battery11measured by the measuring unit12may be transmitted to the battery SOH estimating apparatus100. The battery SOH estimating apparatus100may estimate the SOH of the battery11based on the voltage, current, and temperature of the battery11received from the measuring unit12.

FIG.9is a diagram schematically showing a battery SOH estimating method according to still another embodiment of the present disclosure.

Preferably, each step of the battery SOH estimating method may be performed by the battery SOH estimating apparatus100. Hereinafter, the content overlapping with the previously described content will be omitted or briefly described.

Referring toFIG.9, the battery SOH estimating method may include an SOH estimating step (S100), a SOC change calculating step (S200), a weight calculating step (S300), and an SOH correcting step (S400).

The SOH estimating step (S100) is a step of estimating a first SOH of a battery based on the measured voltage and current of the battery, and may be performed by the SOH estimating unit110.

The SOC change calculating step S200is a step of calculating a SOC change region and a SOC change amount of the battery based on the measured voltage, and may be performed by the SOC change calculating unit120.

The SOC change calculating unit120may calculate the SOC change region and the SOC change amount between the start SOC and the end SOC of the battery in one cycle, respectively.

For example, when the battery is charged from 30% SOC to 80% SOC, the SOC change calculating unit120may calculate the SOC change amount as 50% and calculate the SOC change region as the SOC 30% to 80% region.

For convenience of explanation, in the embodiment ofFIG.9, it is shown that the SOC change calculating step (S200) is performed after the SOH estimating step (S100), but it should be noted that the order of performing the SOH estimating step (S100) and the SOC change calculating step (S200) is not limited to the embodiment ofFIG.9. For example, after the SOC change calculating step (S200) is performed first, the SOH estimating step (S100) may be performed, or the SOH estimating step (S100) and the SOC change calculating step (S200) may be performed in parallel.

The weight calculating step (S300) is a step of calculating a weight based on a SOC region factor calculated by comparing the SOC change region with a preset criterion SOC region, a SOC change amount factor based on the SOC change amount, and a temperature factor based on the measured temperature of the battery, and may be performed by the weight calculating unit130.

For example, the weight calculating unit130may calculate the SOC region factor for the SOC change region based on the SOC region factor table. Also, the weight calculating unit130may calculate the SOC change amount factor for the SOC change amount based on the SOC change amount factor table. Also, the weight calculating unit130may calculate the temperature factor for the temperature of the battery based on the temperature factor table. In addition, the weight calculating unit130may calculate the weight by multiplying the calculated SOC region factor, the calculated SOC change amount factor, and the calculated temperature factor.

The SOH correcting step (S400) is a step of correcting the first SOH according to the calculated weight and a preset second SOH, and may be performed by the SOH correcting unit140.

For example, the SOH correcting unit140may correct the first SOH by adding a value obtained by multiplying the first SOH by a weight (α) and a value obtained by multiplying the second SOH by a complement (1−α) of the weight.

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

The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description.

In addition, since the present disclosure described above can be substituted, modified and changed in various ways by those skilled in the art without departing from the technical idea of the present disclosure, the present disclosure is not limited by the embodiments described above and the accompanying drawings, and all or some of the embodiments may be selectively combined to enable various modifications.

EXPLANATION OF REFERENCE SIGNS

10: battery pack11: battery12: measuring unit13: current measuring unit100: battery SOH estimating apparatus110: SOH estimating unit120: SOC change calculating unit130: weight calculating unit140: SOH correcting unit150: storage unit