KR20220146255A - Apparatus and method for diagnosing battery - Google Patents

Abstract

An apparatus for diagnosing a battery according to an embodiment of the present invention includes: a voltage measuring unit configured to measure a voltage of each of a plurality of battery cells and measure a voltage variation of each of the plurality of battery cells at predetermined time intervals; and a control unit which is configured to calculate a voltage deviation for each of the plurality of battery cells based on a plurality of voltage variations measured by the voltage measuring unit, calculate a cumulative deviation obtained by integrating voltage deviations for each of the plurality of battery cells for each of the plurality of battery cells, set a standard deviation interval based on the calculated plurality of cumulative deviations, determine one or more target cells from among the plurality of battery cells, and diagnose the state of each target cell based on a result of comparing the standard deviation interval with the cumulative deviation of each determined target cell. The present invention diagnoses the condition of a plurality of battery cells in a non-destructive way.

Description

BATTERY DIAGNOSTIC DEVICES AND METHODS

The present invention relates to a battery diagnosis apparatus and method, and more particularly, to a battery diagnosis apparatus and method capable of diagnosing states of a plurality of battery cells based on voltages of the plurality of battery cells.

Recently, as the demand for portable electronic products such as laptops, video cameras, and portable telephones is rapidly increasing, and development of electric vehicles, energy storage batteries, robots, satellites, etc. is in full swing, high-performance batteries that can be repeatedly charged and discharged have been developed. Research is actively underway.

Currently, commercially available batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium batteries. It is attracting attention due to its low energy density and high energy density.

In general, a voltage of a battery is measured, and an abnormal battery is detected based on the measured voltage. For example, whether the battery is an abnormal battery is detected based on a magnitude comparison between the voltage of the battery and a set threshold voltage. Since the conventional method has to measure an open circuit voltage (OCV) after the battery is fully charged and compare the measured OCV with a threshold voltage, there is a limitation in that it takes a long time to detect an abnormal battery.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery diagnosis apparatus and method for diagnosing states of a plurality of battery cells in a non-destructive manner based on voltages of the plurality of battery cells. .

Other objects and advantages of the present invention may be understood by the following description, and will become more clearly understood by the examples of the present invention. In addition, it will be readily apparent that the objects and advantages of the present invention can be realized by means and combinations thereof indicated in the claims.

According to an aspect of the present invention, a battery diagnosis apparatus includes: a voltage measuring unit configured to measure a voltage of each of a plurality of battery cells and measure a voltage change amount of each of the plurality of battery cells at a predetermined time interval; and calculating a voltage deviation for each of the plurality of battery cells based on a plurality of voltage variations measured by the voltage measuring unit, and accumulating the voltage deviation for each of the plurality of battery cells for each of the plurality of battery cells Calculating a deviation, setting a reference deviation interval based on the calculated plurality of accumulated deviations, determining one or more target cells among the plurality of battery cells, and comparing the accumulated deviation of each determined target cell with the reference deviation interval and a control unit configured to diagnose the state of each of the target cells based on the result.

The controller may be configured to calculate an average and standard deviation for the plurality of accumulated deviations, and set the reference deviation interval based on the calculated average and standard deviation.

The control unit calculates a weight value by adding a preset weight to the standard deviation, sets a value obtained by adding the weight value to the calculated average as an upper limit of the reference deviation interval, and sets the weight value from the calculated average It may be configured to set a value obtained by subtracting ? as a lower limit of the reference deviation interval.

The controller may be configured to determine, as the target cell, a battery cell corresponding to a maximum value and a battery cell corresponding to a minimum value among a plurality of calculated cumulative deviations.

The controller may be configured to determine the plurality of battery cells as the target cells.

The controller may be configured to diagnose the state of each target cell as a normal state or an abnormal state based on whether the accumulated deviation of each of the target cells belongs to the reference deviation interval.

The control unit sets a counting coefficient for each of the plurality of battery cells based on a voltage deviation for each of the plurality of battery cells, and when the accumulated deviation of at least one target cell does not fall within the reference deviation period, the It may be configured to diagnose the state of the target cell based on a counting coefficient set for the target cell.

The controller may be configured to compare the voltage deviation of each of the plurality of battery cells with a preset reference voltage section, and set a counting coefficient for each of the plurality of battery cells based on the comparison result.

The controller may be configured to increase a counting coefficient for a corresponding battery cell when the voltage deviation exceeds an upper limit of the reference voltage section.

The controller may be configured to decrease a counting coefficient for a corresponding battery cell when the voltage deviation is less than a lower limit of the reference voltage section.

The control unit, after setting the counting coefficients for each of the plurality of battery cells, if the maximum and minimum values of the plurality of voltage deviations calculated for the plurality of battery cells do not all fall within a preset threshold period, the plurality of and end state diagnosis of the plurality of battery cells at a current time without calculating the accumulated deviation for the battery cells of .

The controller may be configured to diagnose the state of the target cell as the normal state when the counting coefficient of the target cell belongs to a preset counting interval.

The controller may be configured to diagnose the state of the target cell as the abnormal state when the counting coefficient of the target cell does not belong to the counting interval.

The controller may be configured to initialize the counting coefficient set in a target cell in which the counting coefficient does not belong to the counting period, and to maintain the counting coefficient set in the remaining battery cells.

A battery pack according to another aspect of the present invention may include the battery diagnosis apparatus according to an aspect of the present invention.

A battery diagnosis method according to another aspect of the present invention includes: a voltage measuring step configured to measure a voltage of each of a plurality of battery cells and measure a voltage change amount of each of the plurality of battery cells at a predetermined time interval; a voltage deviation calculating step of calculating a voltage deviation for each of the plurality of battery cells based on the plurality of voltage variations measured in the voltage measuring step; a cumulative deviation calculating step of calculating a cumulative deviation obtained by accumulating voltage deviations for each of the plurality of battery cells for each of the plurality of battery cells; a reference deviation section setting step of setting a reference deviation section based on the plurality of accumulated deviations calculated in the cumulative deviation calculating step; a target cell determination step of determining one or more target cells among the plurality of battery cells; and a state diagnosis step of diagnosing the state of each target cell based on a result of comparing the reference deviation period with the accumulated deviation of each target cell determined in the target cell determination step.

According to an aspect of the present invention, the states of the plurality of battery cells may be non-destructively diagnosed based on the voltages of the plurality of battery cells. In particular, the state of the battery module may be diagnosed based on the voltage deviation between the plurality of battery cells.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Since the following drawings attached to the present specification serve to further understand the technical idea of the present invention together with the detailed description of the present invention to be described later, the present invention should not be construed as being limited only to the matters described in such drawings.
1 is a diagram schematically illustrating an apparatus for diagnosing a battery according to an embodiment of the present invention.
2 is a diagram schematically illustrating a battery pack including a battery diagnosis apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram schematically illustrating an exemplary configuration of the battery pack of FIG. 2 .
4 is a diagram schematically illustrating a method for diagnosing a battery according to an embodiment of the present invention.
5 is a diagram schematically illustrating an embodiment further including a counting coefficient setting step in the battery diagnosis method of FIG. 4 .
FIG. 6 is a diagram illustrating a state diagnosis step in more detail in response to the counting coefficient setting step of FIG. 5 .
FIG. 7 is a diagram schematically illustrating an embodiment that further includes the step of determining whether a state is diagnosed in the method for diagnosing the battery of FIG. 5 .

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in the present specification is merely the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

In addition, in the description of 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 thereof will be omitted.

Terms including an ordinal number such as 1st, 2nd, etc. are used for the purpose of distinguishing any one of various components from the others, and are not used to limit the components by such terms.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

In addition, throughout the specification, when a part is "connected" with another part, it is not only "directly connected" but also "indirectly connected" with another element interposed therebetween. include

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

1 is a diagram schematically illustrating a battery diagnosis apparatus 100 according to an embodiment of the present invention. 2 is a diagram schematically illustrating a battery pack 1 including the battery diagnosis apparatus 100 according to an embodiment of the present invention. FIG. 3 is a diagram schematically illustrating an exemplary configuration of the battery pack 1 of FIG. 2 .

Referring to FIG. 1 , the battery diagnosis apparatus 100 may include a voltage measurement unit 110 and a control unit 120 .

The voltage measuring unit 110 may be configured to measure the voltage of each of the plurality of battery cells, and measure the voltage change amount of each of the plurality of battery cells at a predetermined time interval.

Here, the battery cell has a negative terminal and a positive terminal, and means one physically separable independent cell. For example, a lithium ion battery or a lithium polymer battery may be considered a battery.

For example, in the embodiments of FIGS. 2 and 3 , the battery pack 1 may include a battery module 10 including a plurality of battery cells. However, although a plurality of battery cells included in the battery module 10 are shown to be connected in series in FIGS. 2 and 3 , the plurality of battery cells may be connected in series and/or in parallel to be provided in the battery module 10 . have. In addition, a plurality of battery modules 10 may be provided in the battery pack 1 . In this case, the connection relationship between the plurality of battery cells included in the plurality of battery modules 10 is preferably the same, but in some cases, the connection relationship between the plurality of battery cells included in the plurality of battery modules 10 may be different. may be

Specifically, the voltage measuring unit 110 may measure a first voltage of each of the plurality of battery cells at a first time point. In addition, the voltage measuring unit 110 may measure the second voltage of each of the plurality of battery cells at a second time point different from the first time point. The voltage measuring unit 110 calculates a difference between the first voltage and the second voltage measured for each battery cell, and may measure a voltage change amount for each battery cell.

For example, the second time point may be a time point when about 15 seconds have elapsed from the first time point. As a specific example, the voltage measuring unit 110 may measure a first voltage for each battery cell at a first time point while the plurality of battery cells are being charged or discharged. In addition, a second voltage for each battery cell may be measured at a second time point when 15 seconds have elapsed from the first time point. Thereafter, the voltage measuring unit 110 may calculate a voltage change amount by calculating a difference between the first voltage and the second voltage for each battery cell.

Preferably, while the voltage change amount is measured by the voltage measuring unit 110 , a minute current may flow into the plurality of battery cells or a minute current may be output from the plurality of battery cells. The voltage measuring unit 110 may measure the voltage change of each of the plurality of battery cells by measuring the voltage change of the plurality of battery cells according to the inflow or output of the minute current.

The control unit 120 may be configured to calculate a voltage deviation for each of the plurality of battery cells based on the plurality of voltage variations measured by the voltage measurement unit 110 .

Specifically, the controller 120 may calculate a representative change amount for a plurality of voltage change amounts. In addition, the controller 120 may calculate the calculated representative change amount and the voltage deviation of each of the plurality of voltage change amounts. Here, the representative change amount may be an average value or a median value.

For example, the controller 120 may calculate the average value by calculating the formula of “the sum of the plurality of voltage variations ÷ the number of the plurality of battery cells”. In addition, the controller 120 may calculate a voltage deviation for each of the plurality of battery cells by calculating a formula of “voltage variation-average value” for each of the plurality of voltage variations.

In the embodiment of FIG. 3 , the controller 120 may calculate an average value of the voltage changes of the first to fifth battery cells 11 to 15 . Also, the controller 120 may calculate a voltage deviation for each of the first to fifth battery cells 11 to 15 by using the calculated average value as a representative change amount.

The controller 120 may be configured to calculate a cumulative deviation obtained by integrating voltage deviations for each of the plurality of battery cells for each of the plurality of battery cells.

Here, the accumulated deviation may be a value obtained by integrating voltage deviations from a previous time point to a current time point.

For example, it is assumed that the first to 99th voltage deviations for the battery cells are calculated from the first cycle to the 99th cycle, and the 100th voltage deviation for the battery cells is calculated even in the current 100th cycle. The controller 120 may calculate the accumulated deviation by integrating the first to the 100th voltage deviations.

In the embodiment of FIG. 3 , the controller 120 may calculate the accumulated deviation by accumulating the voltage deviation for each of the first to fifth battery cells 11 to 15 .

The controller 120 may be configured to set a reference deviation interval based on the plurality of calculated accumulated deviations.

Here, the reference deviation section is a deviation section that can be set based on a plurality of accumulated deviations calculated by the controller 120 , and can be adaptively set based on the plurality of accumulated deviations.

Specifically, the controller 120 may be configured to calculate an average and standard deviation for a plurality of accumulated deviations, and set a reference deviation interval based on the calculated average and standard deviation.

First, the controller 120 may calculate a weight value by adding a preset weight to the standard deviation.

For example, the weight is a preset value and may be set as a positive number between 1 and 5. When the weight is set to 3, the weight value obtained by adding the weight to the standard deviation σ may be 3σ.

Next, the controller 120 may be configured to set a value obtained by adding a weight value to the calculated average as the upper limit of the reference deviation section, and set a value obtained by subtracting the weight value from the calculated average as the lower limit of the reference deviation period.

With reference to the previous embodiment, it is assumed that the weight value is 3σ and the average is x. The controller 120 may calculate an expression of “x+3σ” and set it as an upper limit of the reference deviation section, and calculate an expression of “x-3σ” to set it as a lower limit of the reference deviation section.

The controller 120 may be configured to determine one or more target cells among a plurality of battery cells.

Specifically, the controller 120 may determine two or more battery cells among the plurality of battery cells as target cells. Here, the number of battery cells determined as target cells may be preset in consideration of quickness and accuracy of the state diagnosis results of the plurality of battery cells. Details of the number of battery cells determined as target cells will be described later.

The controller 120 may be configured to diagnose the state of each target cell based on a result of comparing the determined cumulative deviation of each target cell with the reference deviation interval.

Specifically, the controller 120 may be configured to diagnose the state of each target cell as a normal state or an abnormal state based on whether the accumulated deviation of each target cell belongs to a reference deviation interval.

For example, in the embodiment of FIG. 3 , it is assumed that the first battery cell 11 and the second battery cell 12 are determined as target cells. When the accumulated deviation of the first battery cell 11 falls within the reference deviation period, the controller 120 may diagnose the state of the first battery cell 11 as a normal state. Conversely, if the accumulated deviation of the second battery cell 12 does not belong to the reference deviation period, the controller 120 may diagnose the state of the second battery cell 12 as an abnormal state.

That is, the controller 120 may diagnose the state of the target cell in consideration of the voltage imbalance between the plurality of battery cells provided together in the battery module 10 and/or the battery pack 1 . Specifically, the diagnosis result by the controller 120 may be a result that reflects the actual operating environment more than a result diagnosed based on an arbitrarily set threshold value (a value set as an ideal reference through theory or experiment). Accordingly, the battery diagnosis apparatus 100 according to an embodiment of the present invention has the advantage of deriving an adaptive state diagnosis result for an actually operated battery cell.

Meanwhile, the controller 120 included in the battery diagnosis apparatus 100 includes a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and a register known in the art to execute various control logics performed in the present invention. , a communication modem, a data processing device, and the like may be optionally included. Also, when the control logic is implemented in software, the controller 120 may be implemented as a set of program modules. In this case, the program module may be stored in the memory and executed by the controller 120 . The memory may be inside or outside the control unit 120 , and may be connected to the control unit 120 by various well-known means.

Also, the battery diagnosis apparatus 100 may further include a storage unit 130 . The storage unit 130 may store data necessary for each component of the battery diagnosis apparatus 100 to perform an operation and function, a program, or data generated while an operation and a function are performed. The storage unit 130 is not particularly limited in its type as long as it is a known information storage means capable of writing, erasing, updating and reading data. As an example, the information storage means may include a RAM, a flash memory, a ROM, an EEPROM, a register, and the like. Also, the storage unit 130 may store program codes in which processes executable by the control unit 120 are defined.

For example, the storage unit 130 stores a voltage change amount for a plurality of battery cells measured by the voltage measurement unit 110 , an accumulated deviation for each of the plurality of battery cells, and a reference deviation section set by the control unit 120 . can The controller 120 may directly receive the voltage change amount for the plurality of battery cells from the voltage measuring unit 110 , or access the storage unit 130 to obtain the voltage change amount stored for each of the plurality of battery cells.

The controller 120 may adjust the number of target cells determined from among the plurality of battery cells.

In an embodiment, the controller 120 may be configured to determine, as a target cell, a battery cell corresponding to a maximum value and a battery cell corresponding to a minimum value among a plurality of calculated cumulative deviations.

For example, in the embodiment of FIG. 3 , it is assumed that the accumulated deviation for the first battery cell 11 is the maximum value and the accumulated deviation for the second battery cell 12 is the minimum value. The controller 120 may determine the first battery cell 11 and the second battery cell 12 as target cells.

In addition, the controller 120 compares the accumulated deviation between the first battery cell 11 and the second battery cell 12 with a reference deviation section to compare the states of the first battery cell 11 and the second battery cell 12 . can be diagnosed

For example, when the accumulated deviation of the first battery cell 11 belongs to the reference deviation period, the controller 120 may diagnose the state of the first battery cell 11 as a normal state. Conversely, when the accumulated deviation of the first battery cell 11 does not belong to the reference deviation period, the controller 120 may diagnose the state of the first battery cell 11 as an abnormal state.

Similarly, when the accumulated deviation of the second battery cell 12 falls within the reference deviation period, the controller 120 may diagnose the state of the second battery cell 12 as a normal state. Conversely, when the accumulated deviation of the second battery cell 12 does not belong to the reference deviation period, the controller 120 may diagnose the state of the second battery cell 12 as an abnormal state.

That is, by determining the target cell as a battery cell having a maximum value and a battery cell having a minimum value, the controller 120 can quickly diagnose a state of a battery cell having the greatest difference in voltage behavior among a plurality of battery cells. If the states of the target cells are all diagnosed as normal, the controller 120 can quickly diagnose the states of the plurality of battery cells because the states of the plurality of battery cells can all be regarded as the normal states. .

In another embodiment, the controller 120 may be configured to determine a plurality of battery cells as target cells.

For example, in the embodiment of FIG. 3 , the controller 120 may determine all of the first to fifth battery cells 11 to 15 as target cells. In addition, the controller 120 controls the accumulated deviation of the first battery cell 11 , the accumulated deviation of the second battery cell 12 , the accumulated deviation of the third battery cell 13 , and the accumulated deviation of the fourth battery cell 14 . and the accumulated deviation of the fifth battery cell 15 may be compared with a reference deviation section, respectively.

Unlike the previous embodiment, the controller 120 may diagnose the state of the battery cells more accurately by diagnosing the states of the plurality of battery cells one by one.

That is, the controller 120 may appropriately change the number of target cells determined from among the plurality of battery cells according to a factor that is more considered between the time required for state diagnosis (fastness) and the accurate state diagnosis result (accuracy). Accordingly, time required for battery diagnosis and system resources may be appropriately adjusted according to the operating environment of the plurality of battery cells.

Hereinafter, an embodiment in which the controller 120 diagnoses the states of a plurality of battery cells by further considering the counting coefficients will be described.

The controller 120 may be configured to set a counting coefficient for each of the plurality of battery cells based on a voltage deviation for each of the plurality of battery cells.

Here, the counting coefficient is a factor obtained by quantifying a voltage deviation between a plurality of battery cells, and may be expressed as an integer. For example, a counting coefficient may be increased for a battery cell having a relatively high voltage, and a counting coefficient may be decreased for a battery cell having a relatively low voltage. Preferably, the initial value of the counting coefficient is 0, and may be increased or decreased by 1.

For example, in the embodiment of FIG. 3 , the controller 120 may set a counting coefficient for each of the first to fifth battery cells 11 to 15 .

Specifically, the controller 120 may be configured to compare the voltage deviation for each of the plurality of battery cells with a preset reference voltage section, and to set a counting coefficient for each of the plurality of battery cells based on the comparison result.

Here, the reference voltage section is a factor that can be compared with the voltage deviation, and refers to a reference section for determining whether a battery cell is in a relative overvoltage state or a relatively low voltage state.

For example, the reference voltage range may be -2mV to 2mV. In this case, the lower limit of the reference voltage section may be -2mV, and the upper limit may be 2mV.

For example, when the voltage deviation exceeds the upper limit of the reference voltage section, the controller 120 may be configured to increase the counting coefficient for the corresponding battery cell. Preferably, the controller 120 may increase the counting coefficient for the corresponding battery cell by 1.

As another example, when the voltage deviation is less than the lower limit of the reference voltage section, the controller 120 may be configured to decrease the counting coefficient for the corresponding battery cell. Preferably, the controller 120 may decrease the counting coefficient for the corresponding battery cell by one.

Also, when the accumulated deviation of at least one target cell does not belong to the reference deviation interval, the controller 120 may be configured to diagnose the state of the target cell based on a counting coefficient set for the target cell.

Preferably, the controller 120 may diagnose the state of the target cell in which the accumulated deviation does not belong to the reference deviation interval based on the counting coefficient. Specifically, the controller 120 may diagnose the state of the target cell according to whether the counting coefficient of the target cell whose accumulated deviation does not belong to the reference deviation interval belongs to a preset coefficient interval.

Here, the counting period may be a preset period in order to determine the voltage behavior of the battery cell. For example, when the counting coefficient belongs to the counting period, the voltage behavior of the corresponding battery cell may be in a relatively constant state. Conversely, if the counting coefficient does not belong to the counting period, the voltage behavior of the corresponding battery cell may be different from that of other battery cells.

For example, if the counting coefficient of the target cell belongs to a preset counting interval, the controller 120 may be configured to diagnose the state of the target cell as a normal state. Conversely, if the counting coefficient of the target cell does not belong to the counting period, the controller 120 may be configured to diagnose the state of the target cell as an abnormal state.

Specifically, the controller 120 considers the difference between the relative accumulated deviations between the plurality of battery cells and the target cell according to whether the accumulated deviation of the target cell belongs to the reference deviation section, and the counting coefficient of the target cell belongs to the counting section. Depending on whether or not to do so, a difference in relative voltage deviation between the plurality of battery cells and the target cell may be considered.

That is, with respect to the plurality of battery cells, the controller 120 may diagnose the state of the battery cells in consideration of both the voltage deviation at the current diagnosis time and the accumulated deviation accumulated from the past diagnosis time. Accordingly, the controller 120 may more accurately diagnose the state of the battery cell by considering both the current and past voltage behavior of the battery cell.

The controller 120 may be configured to initialize a counting coefficient set in a target cell whose counting coefficient does not belong to a counting interval, and to maintain the counting coefficient set in the remaining battery cells.

Preferably, the controller 120 may reset the counting coefficient for the target cell by initializing the counting coefficient for the corresponding target cell. In addition, the controller 120 may transmit information on the target cell diagnosed as abnormal to a user or an external server.

Specifically, the counting coefficient may be a value that is integrated for each diagnosis time point. Accordingly, the counting coefficients set at the current diagnosis time may be values that reflect all the counting coefficients set at the previous diagnosis time. Also, the state of the target cell in which the counting coefficient set at the current diagnosis time does not belong to a preset counting interval may be diagnosed as an abnormal state. Accordingly, the controller 120 initializes the counting coefficients of the target cells in which the counting coefficients set at the current diagnosis time do not belong to the preset counting period, so that the counting coefficients for the corresponding target cells are calculated in consideration of only the voltage deviation from the subsequent diagnosis time. can be reset.

If the state of the target cell is diagnosed as an abnormal state even at the time of diagnosis after the counting coefficient is initialized, the number of abnormal state diagnoses for the target cell is accumulated, so the reliability of the state diagnosis result for the target cell is increased can be

However, in the above, an embodiment in which the controller 120 diagnoses the state of the target cell as an abnormal state after initializing the counting coefficient of the target cell has been described, but the controller 120 diagnoses the state of the target cell as an abnormal state Note that the counting coefficient set in the corresponding target cell may be initialized.

After setting the counting coefficients for each of the plurality of battery cells, the controller 120 determines that if the maximum and minimum values of the plurality of voltage deviations calculated for the plurality of battery cells do not all fall within a preset threshold period, the plurality of batteries It may be configured to terminate the state diagnosis of the plurality of battery cells at the current time without calculating the cumulative deviation for the cells.

Here, the critical section is a section including the reference voltage section, and depending on whether the voltage deviation belongs to the critical section, it is a factor used as a criterion for determining whether the voltage change amount of the plurality of battery cells measured at the current diagnosis time is reliable. can For example, the threshold period may be preset to -10mV to 10mV.

For example, the voltage change amount measured by the voltage measuring unit 110 may be inaccurate due to noise generated inside and/or outside the battery diagnosis apparatus 100 . If the states of a plurality of battery cells are diagnosed by such an inaccurate amount of voltage change, there is a problem that the diagnosis result may also be inaccurate. Accordingly, the controller 120 may determine whether the noise has an influence in the voltage change amount measurement process by checking whether both the maximum and minimum values of the plurality of voltage deviations do not belong to the threshold section. If both the maximum and minimum values of the plurality of voltage deviations do not belong to the critical section, the control unit 120 determines that the noise has affected the voltage change amount measurement process, and sets the counting coefficient but does not calculate the cumulative deviation have.

The battery diagnosis apparatus 100 according to the present invention may be applied to a battery management system (BMS). That is, the BMS according to the present invention may include the battery diagnosis apparatus 100 described above. In this configuration, at least some of the respective components of the battery diagnosis apparatus 100 may be implemented by supplementing or adding functions of components included in the conventional BMS. For example, the voltage measurement unit 110 , the control unit 120 , and the storage unit 130 of the battery diagnosis apparatus 100 may be implemented as components of the BMS.

Also, the battery diagnosis apparatus 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 diagnosis apparatus 100 and one or more battery cells. In addition, the battery pack 1 may further include electrical equipment (relays, fuses, etc.) and a case.

2 and 3 , the battery pack 1 includes one battery module 10 , and the battery module 10 includes a first battery cell 11 and a second battery cell 12 connected in series. , a third battery cell 13 , a fourth battery cell 14 , and a fifth battery cell 15 may be included.

However, unlike the embodiment of FIG. 3 , a plurality of battery cells included in the battery module 10 may be connected to each other in series and/or in parallel. That is, a connection relationship between a plurality of battery cells included in the battery module 10 may be applied without limitation.

Also, unlike the embodiment of FIG. 3 , a plurality of battery modules 10 may be included in the battery pack 1 .

Referring to FIG. 3 , the voltage measuring unit 110 includes a first sensing line SL1 , a second sensing line SL2 , a third sensing line SL3 , a fourth sensing line SL4 , and a fifth sensing line ( SL5) and the sixth sensing line SL6.

Specifically, the voltage measuring unit 110 may measure the amount of change in the voltage of the first battery cell 11 through the first sensing line SL1 and the second sensing line SL2 . The voltage measuring unit 110 may measure a voltage change amount of the second battery cell 12 through the second sensing line SL2 and the third sensing line SL3 . The voltage measuring unit 110 may measure the amount of change in the voltage of the third battery cell 13 through the third sensing line SL3 and the fourth sensing line SL4 . The voltage measuring unit 110 may measure the amount of change in the voltage of the fourth battery cell 14 through the fourth sensing line SL4 and the fifth sensing line SL5 . The voltage measuring unit 110 may measure a voltage change amount of the fifth battery cell 15 through the fifth sensing line SL5 and the sixth sensing line SL6 .

4 is a diagram schematically illustrating a method for diagnosing a battery according to an embodiment of the present invention.

Preferably, each step of the battery diagnosis method may be performed by the battery diagnosis apparatus 100 . Hereinafter, for convenience of description, the content overlapping with the previously described content will be omitted or briefly described.

4 , the battery diagnosis method includes a voltage measurement step (S100), a voltage deviation calculation step (S200), a cumulative deviation calculation step (S300), a reference deviation interval setting step (S400), a target cell determination step (S500), and It may include a state diagnosis step (S600).

The voltage measuring step ( S100 ) is a step of measuring the voltage of each of the plurality of battery cells and measuring the voltage change amount of each of the plurality of battery cells at a predetermined time interval, and may be performed by the voltage measuring unit 110 . .

For example, in the embodiment of FIG. 3 , the voltage measuring unit 110 may measure a voltage change amount for each of the first to fifth battery cells 11 to 15 .

The voltage deviation calculating step S200 is a step of calculating a voltage deviation for each of the plurality of battery cells based on the plurality of voltage variations measured in the voltage measuring step S100 , and may be performed by the controller 120 .

For example, in the embodiment of FIG. 3 , the controller 120 may calculate a representative change amount with respect to the voltage change amount of the first to fifth battery cells 11 to 15 . Preferably, the representative change amount may be an average value.

The step of calculating the accumulated deviation ( S300 ) is a step of calculating the accumulated deviation obtained by integrating the voltage deviation of each of the plurality of battery cells for each of the plurality of battery cells, and may be performed by the controller 120 .

For example, in the embodiment of FIG. 3 , the controller 120 may calculate the accumulated deviation by integrating the voltage deviation calculated from the previous time point to the present time point for each of the first to fifth battery cells 11 to 15 .

The step of setting the reference deviation section ( S400 ) is a step of setting a reference deviation section based on the plurality of accumulated deviations calculated in the step of calculating the cumulative deviation ( S300 ), and may be performed by the controller 120 .

For example, the controller 120 may calculate an average and standard deviation for a plurality of accumulated deviations. In addition, the controller 120 may calculate a weight value by applying a weight to the standard deviation. The controller 120 may set the upper limit of the reference deviation section by adding a weight value to the average, and set the difference between the average and the weight value as the lower limit of the reference deviation section.

3 , a cumulative deviation may be calculated for each of the first to fifth battery cells 11 to 15 . In addition, the controller 120 may set a reference deviation section adaptive to the first to fifth battery cells 11 to 15 based on a plurality of accumulated deviations.

The target cell determination step S500 is a step of determining one or more target cells among a plurality of battery cells, and may be performed by the controller 120 .

The number of target cells determined by the controller 120 may be adjusted in consideration of the speed and accuracy of state diagnosis for a plurality of battery cells. That is, in the case of rapid status diagnosis, the number of target cells determined may be smaller than in the case of accurate status diagnosis.

For example, it is assumed that the battery pack 1 is provided in a vehicle. When a plurality of battery cells are temporarily charged or discharged while driving a vehicle, two target cells may be determined for rapid state diagnosis. Conversely, when the vehicle is parked after the operation of the vehicle is finished, all battery cells may be determined as target cells for accurate state diagnosis.

The state diagnosis step (S600) is a step of diagnosing the state of each target cell based on the result of comparing the accumulated deviation and the reference deviation period of each target cell determined in the target cell determination step (S500), and is performed by the controller 120 can be performed.

Specifically, the controller 120 may be configured to diagnose the state of each target cell as a normal state or an abnormal state based on whether the accumulated deviation of each target cell belongs to a reference deviation interval.

For example, in the embodiment of FIG. 3 , it is assumed that the first battery cell 11 and the second battery cell 12 are determined as target cells. When the accumulated deviation of the first battery cell 11 falls within the reference deviation period, the controller 120 may diagnose the first battery cell 11 as a normal state. Conversely, when the accumulated deviation of the first battery cell 11 does not belong to the reference deviation period, the controller 120 may diagnose the first battery cell 11 as an abnormal state. Similarly, the controller 120 may diagnose the state of the second battery cell 12 as a normal state or an abnormal state according to whether the accumulated deviation of the second battery cell 12 belongs to the reference deviation period.

FIG. 5 is a diagram schematically illustrating an embodiment that further includes a counting coefficient setting step ( S700 ) in the battery diagnosis method of FIG. 4 . FIG. 6 is a diagram illustrating the state diagnosis step S600 in more detail in response to the counting coefficient setting step S700 of FIG. 5 .

Referring to FIG. 5 , the battery diagnosis method may further include a counting coefficient setting step ( S700 ). Preferably, the counting coefficient setting step ( S700 ) may be performed after the voltage deviation calculation step ( S200 ).

The counting coefficient setting step S700 is a step of setting a counting coefficient for each of the plurality of battery cells based on the voltage deviation for each of the plurality of battery cells, and may be performed by the controller 120 .

In step S710 , the controller 120 may select any one of a plurality of battery cells.

In operation S720 , the controller 120 may determine whether the voltage deviation of the selected battery cell exceeds the upper limit of the reference voltage section. If the determination result of step S720 is YES, step S730 may be performed, and if NO, step S740 may be performed.

In operation S730, when the voltage deviation of the selected battery cell exceeds the upper limit of the reference voltage section, the controller 120 may increase the counting coefficient for the corresponding battery cell. For example, the controller 120 may increase the counting coefficient for the corresponding battery cell by 1.

In operation S740, the controller 120 may determine whether the voltage deviation of the selected battery cell is less than the lower limit of the reference voltage section. If the determination result of step S740 is YES, step S750 may be performed, and if NO, step S760 may be performed.

In operation S750 , when the voltage deviation of the selected battery cell is less than the lower limit of the reference voltage section, the controller 120 may decrease the counting coefficient for the corresponding battery cell. For example, the controller 120 may decrease the counting coefficient for the corresponding battery cell by one.

In operation S760 , the controller 120 may determine whether counting coefficient setting for the plurality of battery cells is completed, and if completed, may perform the operation of calculating the cumulative deviation ( S300 ).

That is, referring to steps S720 to S750, the counting coefficient for battery cells in which the voltage deviation exceeds the upper limit of the reference voltage section is increased, and the counting coefficient for the battery cells in which the voltage deviation is less than the lower limit of the reference voltage section can be decreased. have. In addition, the counting coefficient for the battery cell in which the voltage deviation belongs to the reference voltage section may be maintained without being changed.

Referring to FIG. 6 , the state diagnosis step S600 may include steps S610 to S650 .

In operation S610, the controller 120 may determine whether the accumulated deviation of the target cell belongs to a reference deviation interval. If the determination result of step S610 is YES, step S620 may be performed, and if NO, step S630 may be performed.

In step S620, the controller 120 may determine the state of the target cell as a normal state.

That is, the controller 120 maintains the counting coefficient of the target cell as it is, and when the accumulated deviation falls within the reference deviation interval, the control unit 120 may diagnose the state of the target cell as a normal state.

In step S630, the controller 120 may determine whether the counting coefficient of the target cell belongs to a preset counting interval. If the determination result of step S630 is YES, step S620 may be performed, and if NO, step S640 may be performed.

In operation S640, the controller 120 may initialize the counting coefficient of the target cell.

And, in step S650, the controller 120 may diagnose the state of the target cell as an abnormal state.

3 , it is assumed that the first battery cell 11 and the second battery cell 12 are determined as target cells.

For example, if the accumulated deviation of the first battery cell 11 falls within the reference deviation section, the controller 120 determines the state of the first battery cell 11 without considering the counting coefficient of the first battery cell 11 . can be considered as normal.

As another example, if the accumulated deviation of the second battery cell 12 does not belong to the reference deviation period, the controller 120 may determine whether the counting coefficient of the second battery cell 12 belongs to the counting period. If the counting coefficient of the second battery cell 12 belongs to the counting period, the controller 120 may diagnose the state of the second battery cell 12 as a normal state. Conversely, if the counting coefficient of the second battery cell 12 does not belong to the counting period, the controller 120 initializes the counting coefficient set in the second battery cell 12 and sets the state of the second battery cell 12 as abnormal. condition can be diagnosed.

However, in the above, an embodiment in which the controller 120 diagnoses the state of the target cell as an abnormal state after initializing the counting coefficient of the target cell has been described, but the controller 120 diagnoses the state of the target cell as an abnormal state Note that the counting coefficient set in the corresponding target cell may be initialized. That is, the execution order of steps S640 and S650 may be changed from each other.

In summary, the controller 120 may primarily diagnose the state of the target cell by comparing the accumulated deviation of the target cell with a reference deviation section set based on the accumulated deviation of the plurality of battery cells. In addition, the controller 120 may secondarily diagnose the state of the target cell by comparing the counting coefficient of the target cell with the counting interval.

Accordingly, since the controller 120 diagnoses the state of the battery cell in consideration of both the voltage deviation and the accumulated deviation of the plurality of battery cells, the state of the battery cell can be more accurately diagnosed.

FIG. 7 is a diagram schematically illustrating an embodiment that further includes the step of determining whether a state is diagnosed ( S800 ) in the method of diagnosing the battery of FIG. 5 .

In the state diagnosis determination step ( S800 ), it is determined whether the state diagnosis on the plurality of battery cells is performed by determining whether the maximum and minimum values of the plurality of voltage deviations calculated for the plurality of battery cells all belong to a preset threshold section. This step may be performed by the controller 120 .

If the determination result of step S760 is YES, the state diagnosis determination step S800 may be performed.

Specifically, if the maximum and minimum values of the plurality of voltage deviations calculated for the plurality of battery cells do not all fall within the preset threshold period, the controller 120 does not calculate the accumulated deviation for the plurality of battery cells at the current time point. may be configured to end the state diagnosis of the plurality of battery cells.

Conversely, when at least one of the maximum and minimum values of the plurality of voltage deviations calculated for the plurality of battery cells belongs to a preset threshold period, the controller 120 may perform the step of calculating the cumulative deviation ( S300 ).

If both the maximum and minimum values of the plurality of voltage deviations do not fall within the threshold section, the controller 120 determines that noise has affected the voltage change amount measurement process, and sets a counting coefficient, but may not calculate the accumulated deviation. Accordingly, since it is prevented that the voltage deviation affected by the noise is continuously accumulated at the current diagnosis time, the controller 120 can more accurately diagnose the states of the plurality of battery cells.

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

In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of the present invention by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various modifications and variations are possible within the scope of equivalents of the claims.

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

1: battery pack
10: battery module
11 to 15: first to fifth batteries
100: battery diagnostic device
110: voltage measuring unit
120: control unit
130: storage

Claims (14)

a voltage measuring unit configured to measure a voltage of each of a plurality of battery cells and measure a voltage change amount of each of the plurality of battery cells at a predetermined time interval; and
A cumulative deviation obtained by calculating a voltage deviation for each of the plurality of battery cells based on a plurality of voltage variations measured by the voltage measuring unit, and accumulating the voltage deviation for each of the plurality of battery cells for each of the plurality of battery cells is calculated, a reference deviation interval is set based on the plurality of calculated cumulative deviations, one or more target cells are determined among the plurality of battery cells, and the accumulated deviation of each of the determined target cells is compared with the reference deviation interval. and a control unit configured to diagnose the state of each of the target cells based on the
According to claim 1,
The control unit is
and calculating an average and standard deviation for the plurality of accumulated deviations, and setting the reference deviation interval based on the calculated average and standard deviation.
3. The method of claim 2,
The control unit is
A weight value is calculated by adding a preset weight to the standard deviation, a value obtained by adding the weight value to the calculated average is set as the upper limit of the reference deviation section, and a value obtained by subtracting the weight value from the calculated average Battery diagnosis apparatus, characterized in that configured to be set as a lower limit of the reference deviation section.
3. The method of claim 2,
The control unit is
and determining, as the target cell, a battery cell corresponding to a maximum value and a battery cell corresponding to a minimum value among a plurality of calculated cumulative deviations.
3. The method of claim 2,
The control unit is
and determine the plurality of battery cells as the target cells.
According to claim 1,
The control unit is
and diagnose the state of each target cell as a normal state or an abnormal state based on whether the accumulated deviation of each of the target cells belongs to the reference deviation interval.
7. The method of claim 6,
The control unit is
A counting coefficient for each of the plurality of battery cells is set based on a voltage deviation for each of the plurality of battery cells, and when the accumulated deviation of at least one target cell does not belong to the reference deviation period, the target cell The battery diagnosis apparatus according to claim 1, configured to diagnose the state of the target cell based on a set counting coefficient.
8. The method of claim 7,
The control unit is
and comparing the voltage deviation of each of the plurality of battery cells with a preset reference voltage section, and setting a counting coefficient for each of the plurality of battery cells based on the comparison result.
9. The method of claim 8,
The control unit is
When the voltage deviation exceeds the upper limit of the reference voltage section, increasing a counting coefficient for a corresponding battery cell,
and if the voltage deviation is less than a lower limit of the reference voltage section, a counting coefficient for a corresponding battery cell is decreased.
8. The method of claim 7,
The control unit is
After setting the counting coefficients for each of the plurality of battery cells, if the maximum and minimum values of the plurality of voltage deviations calculated for the plurality of battery cells do not all fall within the preset threshold period, and terminating the state diagnosis of the plurality of battery cells at a current time without calculating the cumulative deviation for the battery diagnosis apparatus.
8. The method of claim 7,
The control unit is
If the counting coefficient of the target cell belongs to a preset counting interval, the state of the target cell is diagnosed as the normal state,
and when the counting coefficient of the target cell does not belong to the counting period, the state of the target cell is diagnosed as the abnormal state.
12. The method of claim 11,
The control unit is
The battery diagnosis apparatus according to claim 1, wherein the counting coefficient is configured to initialize the counting coefficient set in a target cell that does not belong to the counting period, and to maintain the counting coefficient set in the remaining battery cells.
A battery pack comprising the battery diagnosis device according to any one of claims 1 to 12.
a voltage measuring step configured to measure a voltage of each of a plurality of battery cells and measure a voltage change amount of each of the plurality of battery cells at a predetermined time interval;
a voltage deviation calculating step of calculating a voltage deviation for each of the plurality of battery cells based on the plurality of voltage variations measured in the voltage measuring step;
a cumulative deviation calculating step of calculating a cumulative deviation obtained by accumulating voltage deviations for each of the plurality of battery cells for each of the plurality of battery cells;
a reference deviation section setting step of setting a reference deviation section based on the plurality of accumulated deviations calculated in the cumulative deviation calculating step;
a target cell determination step of determining one or more target cells among the plurality of battery cells; and
and a state diagnosis step of diagnosing the state of each target cell based on a result of comparing the accumulated deviation of each target cell determined in the target cell determination step and the reference deviation interval.

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