KR20230168900A - Apparatus and method for diagnosing battery - Google Patents

Abstract

A battery diagnostic device according to an aspect of the present invention includes a measuring unit configured to measure the voltage of the battery at preset voltage measurement cycles for a predetermined period of time after charging of the battery is completed; and calculating a voltage difference between the voltages of the battery measured at each voltage measurement period, comparing the plurality of voltage differences calculated during the predetermined time with a preset threshold, and determining the state of the battery based on the comparison result. May include configured processors.

Description

Battery diagnostic device and method {APPARATUS AND METHOD FOR DIAGNOSING BATTERY}

The present invention relates to a battery diagnosis device and method, and more specifically, to a device and method for diagnosing the state 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.

Although much research is being done on these batteries in terms of increasing capacity and density, improvements in lifespan and safety are also important. To achieve this, it is necessary to suppress the decomposition reaction with the electrolyte on the electrode surface and prevent overcharge and overdischarge.

In particular, it is necessary to prevent lithium precipitation on the surface of the cathode (lithium plating, Li-plating). When lithium is deposited on the surface of the cathode, it causes side reactions with the electrolyte and changes in the kinetic balance of the battery, causing battery deterioration. In addition, as lithium is deposited on the surface of the negative electrode, an internal short circuit of the battery may occur, so there is a risk of ignition or explosion due to an internal short circuit. Therefore, there is a need to develop a technology that can detect whether lithium metal is deposited on the surface of the cathode.

The present invention was made to solve the above problems, and its purpose is to provide a battery diagnostic device and method that can quickly determine whether lithium is deposited by checking the voltage of the battery.

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 diagnostic device according to an aspect of the present invention includes a measuring unit configured to measure the voltage of the battery at preset voltage measurement cycles for a predetermined period of time after charging of the battery is completed; and calculating a voltage difference between the voltages of the battery measured at each voltage measurement period, comparing the plurality of voltage differences calculated during the predetermined time with a preset threshold, and determining the state of the battery based on the comparison result. May include configured processors.

Here, the processor may be configured to calculate a representative value based on the plurality of voltage differences and compare the calculated representative value with the threshold value.

Additionally, the processor may be configured to calculate a minimum value, maximum value, average value, or median value of the plurality of voltage differences as the representative value.

In addition, when the representative value exceeds a preset threshold, the processor determines that the state of the battery is abnormal, and when the representative value is less than or equal to the threshold, the processor determines that the state of the battery is normal. It can be configured.

Additionally, the predetermined time is preset for a predetermined period immediately after charging of the battery is terminated, and the battery may be in an idle state for the predetermined time.

Additionally, the processor may be configured to change the preset threshold based on the SOH of the battery.

Additionally, the processor may be configured to increase the threshold as the SOH of the battery decreases.

Additionally, the processor may be configured to set the threshold based on the SOC of the battery at the time the charging is completed.

Additionally, the processor may be configured to select an SOC section to which the SOC of the battery belongs from a plurality of preset SOC sections and set a reference value corresponding to the selected SOC section as the threshold value.

In addition, the plurality of SOC sections each have a corresponding reference value set, and the reference value corresponding to the high SOC section may be set to be greater than or equal to the reference value corresponding to the low SOC section.

Additionally, the processor may be configured to calculate the voltage difference by calculating the difference between the voltage of the previous cycle and the voltage of the current cycle at each voltage measurement cycle.

Additionally, a battery pack according to another aspect of the present invention for achieving the above object may include a battery diagnostic device according to the present invention.

Additionally, a vehicle according to another aspect of the present invention for achieving the above object may include a battery diagnostic device according to the present invention.

In addition, a battery diagnosis method according to another aspect of the present invention for achieving the above object includes a voltage measurement step of measuring the voltage of the battery at a preset voltage measurement period for a predetermined period of time after charging of the battery is completed; A voltage difference calculation step of calculating a voltage difference between battery voltages measured at each voltage measurement period; A comparison step of comparing a plurality of voltage differences calculated during the predetermined time period with a preset threshold value; and a battery state determination step of determining the state of the battery based on the comparison result of the comparison step.

According to one aspect of the present invention, there is an advantage in that lithium precipitation in the battery can be determined in a non-destructive manner based on battery measurement information, and use of the battery can be appropriately controlled according to the determination result.

Additionally, according to one aspect of the present invention, there is an advantage of being able to quickly determine whether lithium is deposited in the battery using only measurement information obtained from the battery.

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 diagnosis device according to an embodiment of the present invention.
Figure 2 is a graph showing an example of voltage measured for a predetermined period of time after completion of charging of the battery.
Figure 3 is a diagram illustrating the battery voltage measured at each voltage measurement cycle.
Figure 4 is a graph showing the voltage and voltage difference of the battery according to one embodiment.
Figure 5 is a graph showing battery voltage and voltage difference according to one embodiment.
FIG. 6 is a schematic diagram of a portion corresponding to a predetermined time in FIG. 5.
FIG. 7 is a diagram illustrating an example of a mapping table mapping SOC and threshold values.
Figure 8 is a diagram illustrating a battery pack including a battery diagnostic device according to the present invention.
Figure 9 is a diagram illustrating an automobile including a battery diagnosis device according to the present invention.
Figure 10 is a flowchart schematically showing a battery diagnosis method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability.

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.

1 is a diagram schematically showing a battery diagnosis device according to an embodiment of the present invention.

Referring to FIG. 1 , the battery diagnosis device 100 may include a measurement unit 110, a processor 120, and a memory 130.

The measuring unit 110 may be configured to measure the voltage of the battery at preset voltage measurement cycles for a predetermined period of time after charging of the battery is completed. 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.

The measurement unit 110 may employ various voltage measurement techniques known at the time of filing of the present invention. For example, the measuring unit 110 may include a voltage sensor known at the time of filing of the present invention. In particular, when the battery diagnosis device 100 according to the present invention is applied to a battery pack, a voltage sensor already provided in the battery pack may be used as the measuring unit 110 according to the present invention.

Based on the control of the processor 120, the measurement unit 110 may measure the voltage of the battery at every preset voltage measurement period for a predetermined period of time after charging of the battery is completed.

The predetermined time is preset for a predetermined period immediately after charging of the battery ends, and the battery may be in an idle state for the predetermined time. Specifically, the predetermined time may correspond to an initial predetermined time during the idle state of the battery, and may be calculated immediately after charging of the battery is terminated.

Figure 2 is a graph showing an example of voltage measured for a predetermined period of time after completion of charging of the battery. The x-axis of the graph in FIG. 2 is time, and the y-axis is the measured voltage of the battery. According to one embodiment, the first time point t1 may correspond to the time when charging of the battery is completed. Referring to FIG. 2, it can be seen that the voltage of the battery fluctuates significantly during a predetermined period of time corresponding to the time interval between the first time point t1 and the second time point t2.

The processor 120 may calculate the voltage difference between the voltages of the batteries measured at each voltage measurement cycle.

Figure 3 is a diagram illustrating the battery voltage measured at each voltage measurement cycle. The x-axis of the graph in FIG. 3 is time, and the y-axis is the measured voltage of the battery. That is, FIG. 3 is intended to help understand how the voltage of the battery fluctuates during a predetermined period of time after completion of charging shown in FIG. 2, and exemplarily displays the battery voltage measured at each voltage measurement cycle.

The processor 120 may calculate the difference between voltages using the periodically measured voltage. For example, the processor 120 may calculate the n-th voltage difference by calculating the difference between the n-th measured voltage of the battery and the n+1-th measured voltage. Hereinafter, n may be a positive integer of 1 or more.

Referring to FIG. 3, a first voltage point (V1) representing the voltage of the first cycle measured for the first time after the first time point (t1) at which charging of the battery ends, measured by the measuring unit 110, two A second voltage point (V2) representing the voltage of the second measured cycle, a third voltage point (V3) representing the voltage of the third measured cycle, and a fourth measured voltage of the fourth cycle. a fourth voltage point (V4) representing the fifth measured voltage of the fifth cycle, a fifth voltage point (V5) representing the sixth measured voltage of the sixth cycle, and seven The seventh voltage point (V7) of the seventh measured cycle is displayed as an example.

Specifically, the processor 120 may be configured to calculate the voltage difference by calculating the difference between the voltage of the previous cycle and the voltage of the current cycle for each voltage measurement cycle.

For example, the processor 120 may calculate the first voltage difference by subtracting the voltage value of the second voltage point V2 from the voltage value of the first voltage point V1. Additionally, the processor 120 may calculate the second voltage difference by subtracting the voltage value of the third voltage point V3 from the voltage value of the second voltage point V2. As described above, the processor 120 may calculate a plurality of voltage differences for the predetermined time period by calculating the difference between the voltage of the previous cycle and the voltage of the current cycle at each voltage measurement cycle.

The processor 120 may compare the plurality of voltage differences calculated during the predetermined time with a preset threshold.

Specifically, the processor 120 may compare a plurality of voltage differences with a threshold value, or compare representative values for a plurality of voltage differences with a threshold value.

The processor 120 may compare a plurality of voltage differences calculated during the predetermined time with a preset threshold. As a result of the comparison, the processor 120 may determine whether the plurality of voltage differences exceed a preset threshold.

For example, the processor 120 may determine whether the absolute value of the first voltage difference exceeds the preset threshold by comparing the absolute value of the first voltage difference with a preset threshold. In the same manner, the processor 120 may determine whether the absolute value of the nth voltage difference exceeds the preset threshold by comparing the absolute value of the nth voltage difference with a preset threshold.

The processor 120 may be configured to determine the state of the battery based on the comparison result.

In one embodiment, the processor 120 determines that the state of the battery is abnormal if any one of the plurality of voltage differences exceeds the threshold, and determines the state of the battery to be normal if all of the plurality of voltage differences are below the threshold. It can be judged that

For example, the processor 120 may determine that the state of the battery is an abnormal state in which lithium is deposited when the absolute value of the nth voltage difference among the calculated absolute values of the plurality of voltage differences exceeds the threshold. Meanwhile, the processor 120 may determine that the state of the battery is a normal state in which lithium is not deposited if all calculated absolute values of the plurality of voltage differences are less than or equal to the threshold value.

That is, the battery diagnosis device 100 according to an embodiment of the present application can diagnose the state of the battery based on the voltage difference for a predetermined period of time after charging of the battery is completed. Therefore, the battery diagnosis device 100 according to one embodiment can easily and non-destructively diagnose a battery in an abnormal state in which lithium is deposited based on the voltage difference without disassembling and analyzing the battery. Additionally, the battery diagnosis device 100 has the advantage of being able to quickly and accurately diagnose the state of the battery for a predetermined period of time after the battery is fully charged. Below, an embodiment in which the processor 120 determines the state of the battery using a representative value calculated based on a plurality of voltage differences and an embodiment in which the threshold value is changed will be described in detail. For convenience of explanation, the content of how the processor 120 diagnoses the state of the battery based on the voltage difference overlaps with the above-described content, and will therefore be briefly described or omitted.

The processor 120 may calculate a representative value based on a plurality of voltage differences and compare the calculated representative value with the threshold value. As a result of the comparison, the processor 120 may determine whether the calculated representative value exceeds a preset threshold. In various embodiments, some of the measured voltages may contain noise.

In general, the voltage value of the battery can be obtained through a measurement process in which an analog value for the voltage of the battery is obtained through a voltage sensing line, and a conversion process in which the obtained analog value is converted to a digital value. That is, the voltage value of the battery may include measurement noise during the measurement process and/or system noise during the conversion process. Accordingly, the processor 120 may compare representative values of a plurality of voltage differences with a threshold value to minimize the influence of noise. That is, the processor 120 can diagnose the state of the battery to be robust against noise.

Accordingly, the battery diagnosis device 100 can obtain results with improved reliability by comparing a representative value calculated based on a plurality of voltage differences with a preset threshold. Below, representative values based on a plurality of voltage differences are described.

The processor 120 may calculate the minimum, maximum, average, or median value of the plurality of voltage differences as the representative value. Below, for convenience of explanation, the representative value is described as the minimum, maximum, average, or median value of a plurality of voltage differences. However, if the value that the processor 120 can obtain by processing the plurality of voltage differences is the representative value, Please note that the value can be applied without limitation.

For example, the processor 120 may determine the minimum value among the absolute values of each of a plurality of voltage differences and calculate the determined minimum value as a representative value. In another example, the processor 120 may determine the maximum value among the absolute values of each of a plurality of voltage differences and calculate the determined maximum value as a representative value. In another example, the processor 120 may determine an average value among the absolute values of each of a plurality of voltage differences and calculate the determined average value as a representative value. In another example, the processor 120 may determine a median value among the absolute values of each of a plurality of voltage differences and calculate the determined median value as a representative value.

Preferably, the processor 120 may calculate an average value of a plurality of voltage differences as a representative value. For example, the processor 120 calculates the absolute value of each of the plurality of voltage differences, calculates an average value from the calculated absolute values, determines the calculated average value as a representative value, and sets the calculated average value to a preset threshold value. It can be determined whether it exceeds .

If the representative value exceeds a preset threshold, the processor 120 may determine that the battery is in an abnormal state, and if the representative value is below the threshold, the processor 120 may determine that the battery is in a normal state.

For example, the processor 120 may determine that the state of the battery is an abnormal state in which lithium is deposited when the representative value determined among the absolute values of the plurality of voltage differences exceeds a preset threshold. Meanwhile, the processor 120 may determine that the state of the battery is a normal state in which lithium is not precipitated if the representative value determined among the absolute values of the plurality of voltage differences is less than or equal to the threshold value. In this way, the processor 120 can reduce the probability of misdiagnosis due to voltage measurement error and derive more accurate diagnosis results by comparing the representative value with a preset threshold. That is, the battery diagnosis device 100 according to one embodiment has the advantage of being able to accurately diagnose the state of the battery.

The processor 120 is operatively connected to other components of the battery diagnosis device 100 and may control various operations of the battery diagnosis device 100. The processor 120 may perform various operations of the battery diagnosis device 100 by executing one or more instructions stored in the memory 130. The processor 120 optionally includes a processor, application-specific integrated circuit (ASIC), chipset, logic circuit, register, communication modem, data processing device, etc. known in the art to execute various control logics performed in the present invention. can do. Additionally, when the control logic is implemented as software, the processor 120 may be implemented as a set of program modules. At this time, the program module may be stored in the memory 130 and executed by the processor 120.

In particular, when the battery diagnosis device 100 according to the present invention is implemented in a form included in a battery pack, the battery pack will include a control device referred to by terms such as a micro controller unit (MCU) or a battery management system (BMS). You can. At this time, the processor 120 may be implemented by components such as an MCU or BMS included in such a general battery pack. Additionally, in this specification, the terms ‘to’ or ‘configured to be’ regarding the operation or function of the processor 120 may include the meaning of ‘programmed to be’.

The memory 130 may be configured to store predetermined data. Specifically, the memory 130 may store a threshold value against which the voltage difference is compared. Additionally, the memory 130 may further store a mapping table that the processor 120 references when the processor 120 changes the threshold. This will be described later.

The memory 130 may store data or programs necessary for each component of the battery diagnosis device 100 to perform operations and functions, or data generated in the process of performing operations and functions. Memory 130 may be internal or external to processor 120 and may be connected to processor 120 by various well-known means. The memory 130 may store at least one program, application, data, or instructions executed by the processor 120. There is no particular limitation on the type of the memory 130 as long as it is a known information storage means that is known to be capable of recording, erasing, updating, and reading data. The memory 130 is a flash memory type, hard disk type, SSD (Solid State Disk) type, SDD (Solid Disk Drive) type, multimedia card micro type, RAM (Random Access Memory), and SRAM (Static RAM). , it may be implemented as at least one of ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), and PROM (Programmable Read Only Memory), but the present invention is not necessarily limited to the specific form of such memory. Additionally, the memory 130 may store program codes in which processes executable by the processor 120 are defined.

According to this configuration of the present invention, the state of the battery can be easily diagnosed in a non-destructive manner based on the voltage change for a predetermined period of time after completion of charging of the battery. A detailed embodiment in which the processor 120 diagnoses the state of the battery will be described with reference to the drawings below.

Figure 4 is a graph showing the voltage and voltage difference of a battery according to one embodiment. Figure 5 is a graph showing battery voltage and voltage difference according to one embodiment.

Figure 4 shows a voltage graph (Va) and a voltage difference profile (Da) representing the voltage of a battery according to one embodiment. The x-axis of the graph in FIG. 4 represents time, and the y-axis of the graph represents the voltage and voltage difference (ΔV) of the battery according to one embodiment. In Figure 4, voltage and voltage difference are displayed on one plane for convenience of explanation. As described above, the voltage difference profile (Da) represents the voltage difference between the voltages of the batteries measured at each preset voltage measurement cycle, expressed in dots. Here, the voltage difference profile (Da) may represent a plurality of voltage differences representing the difference between the nth voltage and the n+1th voltage, expressed as dots.

Referring to FIG. 4, at a first time point t1, charging of the battery is completed and the battery may be in an idle state. Referring to the voltage graph (Va), after charging is completed, the voltage of the battery may decrease by a predetermined amount due to a polarization phenomenon inside the battery. Here, referring to the voltage difference profile (Da), when the battery according to one embodiment is in a normal state, the calculated plurality of voltage differences may be less than or equal to a preset threshold. Alternatively, when the battery according to one embodiment is in a normal state, a representative value based on the plurality of voltage differences may be less than or equal to a preset threshold. The processor 120 may diagnose the state of the battery by determining that the battery is in a normal state when the calculated plurality of voltage differences or a representative value based on the plurality of voltage differences is less than or equal to a preset threshold.

Figure 5 shows a voltage graph (Vb) and a voltage difference profile (Db) representing the voltage of a battery according to one embodiment. Similar to FIG. 4, the x-axis of the graph in FIG. 5 represents time, and the y-axis of the graph represents the voltage and voltage difference (ΔV) of the battery according to one embodiment.

Referring to FIG. 5, after charging of the battery is completed at the first time point t1, the battery may be in an idle state, and the voltage of the battery may be reduced by a predetermined amount after charging is completed. Here, referring to the voltage difference profile (Db), when the battery according to one embodiment is in an abnormal state, at least one of the plurality of voltage differences calculated for a predetermined time after the first time point (t1) when charging is completed is preset. The threshold may be exceeded. Alternatively, when the battery according to one embodiment is in an abnormal state, a representative value based on a plurality of voltage differences may exceed a preset threshold. As explained with reference to FIG. 5, the processor 120 calculates the voltage difference of the battery during a predetermined time corresponding to the second time point (t2) from the first time point (t1) when charging of the battery is completed, and the calculated The state of the battery can be easily diagnosed depending on whether the voltage difference exceeds a preset threshold. That is, the processor 120 may diagnose the state of the battery by determining that the battery is in an abnormal state when the calculated plurality of voltage differences or a representative value based on the plurality of voltage differences exceeds a preset threshold.

FIG. 6 is a schematic diagram of a portion (a1) corresponding to a predetermined time in FIG. 5.

Referring to the voltage graph in FIG. 6, it can be seen that the voltage of the battery fluctuates significantly during a predetermined period of time from the first time point (t1) when charging of the battery is completed to the second time point (t2). Here, the processor 120 may calculate the voltage difference by calculating the difference between periodically measured voltages. The plurality of voltage differences Db1, Db2, and Db3 in FIG. 6 illustratively illustrate a portion of the voltage difference profile Db in FIG. 5. The processor 120 may compare the calculated voltage difference with a preset threshold and, if the calculated voltage difference exceeds the threshold, determine the state of the battery as an abnormal state in which lithium is deposited on the negative electrode. Additionally, the processor 120 may compare the calculated voltage difference with a preset threshold and, if the calculated voltage difference is less than or equal to the threshold, determine the state of the battery as a normal state in which lithium is not deposited on the negative electrode.

Below, an embodiment in which the processor 120 determines the state of the battery by changing the threshold will be described in detail.

In one embodiment, the processor 120 may be configured to change the preset threshold based on the state of health (SOH) of the battery.

Specifically, the larger the SOH of the battery, the smaller the voltage difference between the batteries may appear, and the smaller the SOH, the larger the voltage difference between the batteries may appear. Therefore, when the SOH of the battery changes from a large value to a small value (i.e., when the battery deteriorates), comparing the voltage difference with the same threshold may result in incorrect diagnosis of the battery condition. Accordingly, the battery diagnosis device 100 can more accurately diagnose the state of the battery by setting the threshold to correspond to the SOH of the battery.

In one embodiment, the processor 120 may be configured to increase the threshold as the SOH of the battery decreases.

Specifically, the processor 120 may estimate the SOH of the battery by comparing the charging capacity or internal resistance value. For example, the measuring unit 110 may further measure the voltage and current of the battery while the battery is being charged. The processor 120 calculates the current charge capacity using the current while the battery is charging, compares the calculated current charge capacity with the reference charge capacity of the BOL (beginning of life) state of the battery, and determines the SOH of the battery. It can be estimated. For another example, the processor 120 may estimate internal resistance using voltage and current while the battery is being charged. As an example, the processor 120 may calculate the internal resistance of the battery using Ohm's law (R=V÷I). The processor 120 may estimate the SOH of the battery by comparing the calculated internal resistance with the reference resistance of the battery's BOL state.

Additionally, the processor 120 may estimate the SOH of the battery using an external server. For example, battery characteristic information related to the voltage and current of the battery measured using the measuring unit 110 may be transmitted to an external server. The external server may estimate the SOH of the battery through various processing processes on the transmitted characteristic information and information previously stored in the database and transmit the estimated SOH to the processor 120. The processor 120 may estimate the received SOH as the SOH of the battery. The processor 120 may use the estimated SOH as described above to set the threshold to an increased value as the SOH of the battery decreases. Accordingly, the processor 120 can more accurately determine the state of the battery even when the SOH of the battery is reduced.

In another embodiment, the processor 120 may set a threshold based on the state of charge (SOC) of the battery at the time when charging of the battery is completed.

Specifically, the larger the SOC of the battery, the larger the voltage difference may appear, and the smaller the SOC of the battery, the smaller the voltage difference may appear. Therefore, when the SOC is large, the state of the battery can be diagnosed more accurately by comparing the voltage difference with a relatively large threshold value compared to when the SOC is small. The processor 120 may recognize the SOC of the battery at the time when charging of the battery is completed and diagnose the state of the battery using a threshold value corresponding to the recognized SOC of the battery.

For example, the processor 120 may be configured to select an SOC section to which the SOC of the battery belongs from a plurality of preset SOC sections and set a reference value corresponding to the selected SOC section as a threshold.

Here, a corresponding reference value is set for each of the plurality of SOC sections, and the reference value corresponding to the high SOC section may be set to be greater than or equal to the reference value corresponding to the low SOC section. This will be described in detail with reference to FIG. 7 .

FIG. 7 is a diagram illustrating an example of a mapping table mapping SOC and threshold values.

Referring to Figure 7, it includes reference values (Vth1, Vth2, Vth3, Vth4, Vth5) corresponding to each of the plurality of SOC sections (0~20, 20~40, 40~60, 60~80, 80~100). A mapping table is shown. The mapping table may be configured so that a relatively large SOC section corresponds to a larger reference value. For example, a section where SOC (%) is 0 to 20 may correspond to the first reference value (Vth1). The section where SOC (%) is 20 to 40 may correspond to the second reference value (Vth2). The section where SOC (%) is 40 to 60 may correspond to the third reference value (Vth3). The section where SOC (%) is 60 to 80 may correspond to the fourth reference value (Vth4). The section where SOC (%) is 80 to 100 may correspond to the fifth reference value (Vth5). Here, the fifth reference value (Vth5) may be greater than or equal to the fourth reference value (Vth4), and the fourth reference value (Vth4) may be greater than or equal to the third reference value (Vth3). Additionally, the third reference value (Vth3) may be greater than or equal to the second reference value (Vth2), and the second reference value (Vth2) may be greater than or equal to the first reference value (Vth1).

The processor 120 may select the SOC section to which the SOC of the battery belongs at the time charging is completed and set a reference value corresponding to the selected SOC section as a threshold. For example, if the SOC of the battery is 85% at the time charging is completed, the processor 120 may set the fifth reference value (Vth5) corresponding to the SOC section to which the battery SOC belongs as a threshold. The processor 120 may diagnose the state of the battery according to the result of comparing the set threshold value (Vth5) and the above-described voltage difference. In another example, when the SOC of the battery is 45% at the time charging is completed, the processor 120 may set the third reference value (Vth3) corresponding to the SOC section to which the SOC of the battery belongs as a threshold. The processor 120 may diagnose the state of the battery according to the result of comparing the set threshold (Vth3) and the above-described voltage difference. According to the above-described embodiment, different threshold values and voltage differences can be compared according to the SOC of the battery at the time when charging of the battery is completed, so the state of the battery can be accurately diagnosed.

According to this embodiment of the present invention, the battery diagnosis device 100 calculates the voltage difference of the battery for a predetermined time after charging of the battery is completed, and easily determines the state of the battery according to the result of comparison with a preset threshold value. You can judge.

The battery diagnosis device 100 according to the present invention can be applied to a BMS. That is, the BMS according to the present invention may include the battery diagnosis device 100 described above. In this configuration, at least some of the components of the battery diagnosis device 100 may be implemented by supplementing or adding functions included in a conventional BMS. For example, the measurement unit 110, processor 120, and memory 130 of the battery diagnosis device 100 may be implemented as components of a BMS.

FIG. 8 is a diagram illustrating a battery pack 10 including a battery diagnostic device 100 according to the present invention.

Referring to FIG. 8, the battery diagnosis device 100 according to the present invention may be provided in the battery pack 10. That is, the battery pack 10 according to the present invention may include the battery diagnosis device 100 according to the present invention described above and one or more battery cells (B). In addition, the battery pack 10 according to the present invention, in addition to the battery diagnosis device 100 according to the present invention, includes components typically included in the battery pack 10, such as one or more secondary batteries, a BMS, and a current sensor (A). ), relays, fuses, pack cases, etc. may be further included. Additionally, at least some components of the battery diagnosis device 100 according to the present invention may be implemented with conventional components included in the battery pack 10. For example, the measurement unit 110 of the battery diagnosis device 100 according to the present invention may be implemented by a voltage sensor included in the battery pack 10. Additionally, at least some functions or operations of the processor 120 of the battery diagnosis device 100 according to the present invention may be implemented by the BMS included in the battery pack 10.

FIG. 9 is a diagram illustrating an automobile 1 including a battery diagnosis device 100 according to the present invention.

Referring to FIG. 9, the battery diagnosis device 100 according to the present invention can be applied to the automobile 1. That is, the automobile 1 according to the present invention may include the battery diagnosis device 100 according to the present invention described above. In particular, in the case of an electric vehicle, the battery pack 10 is a very important component as a driving source, so the battery diagnosis device 100 according to the present invention can be more usefully applied. In addition, the automobile 1 according to the present invention, in addition to the battery diagnosis device 100, includes various other devices, such as a vehicle body, a vehicle control unit such as an ECU (Electronic control unit), a motor, a connection terminal, and a DC-DC converter. It may further include the like. In addition, of course, the automobile 1 according to the present invention can further employ components typically included in automobiles.

Figure 10 is a flowchart schematically showing a battery diagnosis method according to an embodiment of the present invention. In FIG. 10, the subject of each step may be each component of the battery diagnosis device 100 according to the present invention described above.

Referring to FIG. 10, the battery diagnosis method according to the present invention may include a voltage measurement step (S110), a voltage difference calculation step (S120), a comparison step (S130), and a battery state determination step (S140).

Step S110 is a step of measuring the voltage of the battery at preset voltage measurement cycles for a predetermined period of time after charging of the battery is completed, and may be performed by the measurement unit 110.

Specifically, as described with reference to FIG. 3 , the measurement unit 110 may measure the voltage of the battery at each preset voltage measurement cycle for a predetermined period of time after charging of the battery is completed.

Step S120 is a step of calculating the voltage difference between the battery voltages measured at each voltage measurement cycle in step S110, and may be performed by the processor 120.

Specifically, the processor 120 may calculate the voltage difference by calculating the difference between the voltage measured in the previous cycle and the voltage measured in the current cycle. For example, the processor 120 may calculate the nth voltage difference by calculating the difference between the nth voltage measured for the nth time and the n+1th voltage measured for the n+1th time.

Step S130 is a step of comparing a plurality of voltage differences calculated during a predetermined time with a preset threshold, and may be performed by the processor 120.

Specifically, the processor 120 may compare a plurality of voltage differences with a threshold value, or compare representative values for a plurality of voltage differences with a threshold value. Here, the representative value is a value that can be calculated by processing a plurality of voltage differences, and may be a value that can represent a plurality of voltage differences. For example, the processor 120 may calculate a representative value as the minimum, maximum, average, or median value of a plurality of voltage differences. Preferably, the processor 120 may calculate an average value of a plurality of voltage differences as a representative value and compare the calculated representative value with a threshold value.

Step S140 is a step of determining the state of the battery based on the comparison result of step S130, and may be performed by the processor 120.

For example, when the voltage difference or a representative value of a plurality of voltage differences exceeds the threshold, the processor 120 may determine that the state of the battery is an abnormal state in which lithium is deposited on the negative electrode. Conversely, when the voltage difference or a representative value of a plurality of voltage differences is less than or equal to the threshold, the processor 120 may determine that the state of the battery is a normal state.

In relation to steps S110 to S140, the contents of the battery diagnosis device 100 according to the present invention described above may be applied in the same or similar manner. Therefore, detailed description of each step of the battery diagnosis method according to the present invention is omitted.

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.

100: Battery diagnostic device
110: measuring unit
120: processor
130: memory

Claims (14)

a measuring unit configured to measure the voltage of the battery at preset voltage measurement cycles for a predetermined period of time after charging of the battery is completed; and
configured to calculate a voltage difference between the voltages of the battery measured at each voltage measurement period, compare the plurality of voltage differences calculated during the predetermined time with a preset threshold, and determine the state of the battery based on the comparison result. A battery diagnostic device including a processor. According to paragraph 1,
The processor,
A battery diagnosis device configured to calculate a representative value based on the plurality of voltage differences and compare the calculated representative value with the threshold value. According to paragraph 2,
The processor,
A battery diagnosis device configured to calculate a minimum value, maximum value, average value, or median value of the plurality of voltage differences as the representative value. According to paragraph 2,
The processor,
If the representative value exceeds a preset threshold, determining that the state of the battery is abnormal,
A battery diagnosis device configured to determine that the state of the battery is in a normal state when the representative value is less than or equal to the threshold value. According to paragraph 1,
The predetermined time is,
A predetermined period of time is set in advance immediately after charging of the battery ends,
The battery is,
A battery diagnostic device that is in an idle state for the predetermined period of time. According to paragraph 1,
The processor,
A battery diagnostic device configured to change the preset threshold based on the SOH of the battery. According to clause 6,
The processor,
A battery diagnostic device configured to increase the threshold as the SOH of the battery decreases. According to paragraph 1,
The processor,
A battery diagnostic device configured to set the threshold based on the SOC of the battery at the time the charging is completed. According to clause 8,
The processor,
A battery diagnosis device configured to select an SOC section to which the SOC of the battery belongs from a plurality of preset SOC sections and set a reference value corresponding to the selected SOC section as the threshold value. According to clause 9,
The plurality of SOC sections are,
A battery diagnosis device in which corresponding reference values are set, and the reference value corresponding to the high SOC section is set to be greater than or equal to the reference value corresponding to the low SOC section. According to paragraph 1,
The processor,
A battery diagnosis device configured to calculate a voltage difference by calculating the difference between the voltage of the previous cycle and the voltage of the current cycle for each voltage measurement cycle. A battery pack comprising the battery diagnostic device according to any one of claims 1 to 11. A vehicle comprising the battery diagnostic device according to any one of claims 1 to 11. A voltage measurement step of measuring the voltage of the battery at preset voltage measurement cycles for a predetermined period of time after charging of the battery is completed;
A voltage difference calculation step of calculating a voltage difference between battery voltages measured at each voltage measurement period;
A comparison step of comparing a plurality of voltage differences calculated during the predetermined time period with a preset threshold value; and
A battery diagnosis method comprising a battery state determination step of determining the state of the battery based on a comparison result of the comparison step.

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