Battery controller, battery pack, electric vehicle, battery diagnosis method, recording medium

Abstract

A battery controller, a battery pack, an electric vehicle, a battery diagnosis method, a recording medium are provided. A battery diagnosis device according to the present application includes: a voltage detector configured to measure a cell voltage of a battery cell; and a control circuit that applies a moving window of a first time length to a reference voltage curve to determine a plurality of sub voltage curves, the reference voltage curve being a time series indicating voltage values of the cell voltage measured at each sampling time within a predetermined period, and determines, for each sub voltage curve, a long-term average voltage value of the sub voltage curve using a first average filter of the first time length, a short-term average voltage value of the sub voltage curve using a second average filter of a second time length shorter than the first time length; and compares each of a plurality of voltage deviations determined for the plurality of sub voltage curves with a first deviation threshold and / or a second deviation threshold to determine whether the battery cell is abnormal.

Description

[0001] This application is a divisional application of the invention patent application with application number 202280006433.0 (international application number PCT / KR2022 / 010158, international application date July 12, 2022, and invention title "Battery diagnostic device, battery pack, electric vehicle and battery diagnostic method"). Technical Field

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0091231, filed on July 12, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] This disclosure relates to a method for diagnosing abnormalities in battery cells. Background Technology

[0004] Recently, the demand for portable electronic products such as laptops, cameras, and mobile phones has increased rapidly, and with the widespread development of electric vehicles, energy storage batteries, robots, and satellites, a great deal of research is underway on rechargeable, high-performance batteries.

[0005] Currently available battery packs include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among them, lithium batteries have almost no memory effect. Therefore, lithium batteries are more popular than nickel-based batteries because they can be charged at any time when convenient, have extremely low self-discharge rate, and high energy density.

[0006] Recently, with the widespread use of applications requiring high voltage (such as electric vehicles and energy storage systems), there is an increasing demand for diagnostic technologies that can accurately detect anomalies in each of the multiple battery cells connected in series in a battery pack.

[0007] Existing technologies typically employ a method of detecting anomalies in each battery cell by comparing the state parameters (e.g., cell voltage) of each cell with the state parameters of at least one of the remaining battery cells. However, such methods have the following drawbacks: (i) they require a large amount of software resources (computational complexity) and time to diagnose anomalies in all battery cells individually due to the number of comparison processes required corresponding to the number of battery cells, and (ii) diagnostic errors are more likely to occur as the number of anomalous battery cells increases. Summary of the Invention

[0008] Technical issues

[0009] This disclosure is designed to solve the above-mentioned problems. Therefore, this disclosure aims to provide a battery diagnostic device, battery pack, electric vehicle, and battery diagnostic method for diagnosing anomalies in a single battery cell or each of a plurality of battery cells connected in series by utilizing the time-dependent changes in the cell voltage of each battery cell, without requiring a process of comparing the cell voltage of each battery cell with the cell voltages of other battery cells.

[0010] These and other objects and advantages of this disclosure will be understood from the following description and will become apparent from embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means set forth in the appended claims and combinations thereof.

[0011] Technical solution

[0012] A battery diagnostic device according to one aspect of this disclosure includes: a voltage detector configured to measure the cell voltage of a battery cell; and a control circuit configured to determine a plurality of sub-voltage curves by applying a moving window of a first time length to a reference voltage curve, the reference voltage curve being a time series indicating voltage values ​​of the cell voltage measured at each sampling time within a predetermined time period. The control circuit is configured to: for each sub-voltage curve, determine a long-term average voltage value of the sub-voltage curve using a first averaging filter of the first time length, determine a short-term average voltage value of the sub-voltage curve using a second averaging filter of a second time length shorter than the first time length, and determine a voltage deviation associated with the sub-voltage curve by subtracting one of the long-term average voltage value and the short-term average voltage value from the other. The control circuit is configured to determine whether the battery cell is abnormal by comparing each of the plurality of voltage deviations determined for the plurality of sub-voltage curves with at least one of a first deviation threshold and a second deviation threshold.

[0013] The first deviation threshold can be a positive number, and the second deviation threshold can be a negative number whose absolute value is equal to the first deviation threshold.

[0014] The control circuit can be configured to determine that the battery cell is abnormal when the voltage deviation of a predetermined number or more of the plurality of sub-voltage curves is greater than the first deviation threshold or less than the second deviation threshold.

[0015] The control circuit can be configured to determine that the battery cell is abnormal when any two of the multiple voltage deviations determined for the multiple sub-voltage curves meet a first requirement, a second requirement, and a third requirement. The first requirement is met when one of the two voltage deviations is equal to or greater than the first deviation threshold. The second requirement is met when the other of the two voltage deviations is equal to or less than the second deviation threshold. The third requirement is met when the time interval between the two voltage deviations is equal to or less than a threshold time.

[0016] The battery diagnostic device may also include a current detector configured to measure the battery current flowing through the battery cell.

[0017] The control circuit can be configured to determine multiple sub-current curves by applying the moving window to a reference current curve, the reference current curve being a time series indicating the current values ​​of the battery current measured at each sampling time within the predetermined time period. The multiple sub-current curves have a one-to-one correspondence with the multiple sub-voltage curves.

[0018] The control circuit can be configured to determine a current change for each sub-current curve, the current change being the difference between the maximum and minimum current values ​​of the sub-current curve, and, provided that the current change is less than a threshold change, determine the long-term average voltage value and the short-term average voltage value of the sub-voltage curve associated with the sub-current curve.

[0019] According to another aspect of this disclosure, the battery pack includes the battery diagnostic device.

[0020] According to another aspect of this disclosure, an electric vehicle includes the battery pack.

[0021] A battery diagnostic method according to another aspect of this disclosure includes: measuring the cell voltage of a battery cell at each sampling time within a predetermined time period, and determining a plurality of sub-voltage curves by applying a moving window of a first time length to a reference voltage curve, the reference voltage curve being a time series of voltage values ​​indicating the cell voltage; for each sub-voltage curve, determining a long-term average voltage value of the sub-voltage curve using a first averaging filter of the first time length, determining a short-term average voltage value of the sub-voltage curve using a second averaging filter of a second time length shorter than the first time length, and determining a voltage deviation associated with the sub-voltage curve by subtracting one of the long-term average voltage value and the short-term average voltage value from the other; and determining whether the battery cell is abnormal by comparing each of the plurality of voltage deviations determined for the plurality of sub-voltage curves with at least one of a first deviation threshold and a second deviation threshold.

[0022] The step of determining whether the battery cell is abnormal may include: determining that the battery cell is abnormal when the voltage deviation of a predetermined number or more of the plurality of sub-voltage curves is greater than the first deviation threshold or less than the second deviation threshold.

[0023] The step of determining whether the battery cell is abnormal may include: determining that the battery cell is abnormal when any two of the multiple voltage deviations determined for the multiple sub-voltage curves meet a first requirement, a second requirement, and a third requirement. The first requirement is met when one of the two voltage deviations is equal to or greater than the first deviation threshold. The second requirement is met when the other of the two voltage deviations is equal to or less than the second deviation threshold. The third requirement is met when the time interval between the two voltage deviations is equal to or less than a threshold time.

[0024] Technical effect

[0025] At least one embodiment of this disclosure can diagnose anomalies in a single battery cell or a plurality of battery cells connected in series by utilizing the time-varying cell voltage of each battery cell, without requiring a process of comparing the cell voltage of each battery cell with the cell voltages of other battery cells. Therefore, it can save the software resources and time required to diagnose anomalies in each battery cell and reduce the risk of diagnostic errors increasing with the number of abnormal battery cells.

[0026] According to at least one embodiment of this disclosure, measurement noise included in the measured cell voltage value of the corresponding battery cell can be effectively removed by calculating the difference between the long-term trend and the short-term trend of the cell voltage of each battery cell, thereby accurately detecting abnormal changes in the cell voltage of the corresponding battery cell.

[0027] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand these and other effects from the appended claims. Attached Figure Description

[0028] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description of the present disclosure, are intended to provide a further understanding of the technical aspects of the present disclosure; therefore, the present disclosure should not be construed as being limited to the drawings.

[0029] Figure 1 A diagram illustrating, by way of example, the components of an electric vehicle according to this disclosure.

[0030] Figure 2 This is an example of a graph showing the voltage curves corresponding to the original time series of the actual voltage values ​​of the cell voltages of the battery cells.

[0031] Figure 3 This exemplifies how measurement noise is mixed in with... Figure 2 The measured voltage curve is obtained by plotting the original time series corresponding to the voltage curve.

[0032] Figure 4 This exemplarily illustrates applying a first averaging filter... Figure 3 The voltage curve is used to obtain the first moving average curve.

[0033] Figure 5 This exemplifies the application of a second averaging filter. Figure 3 The second moving average curve is obtained from the voltage curve.

[0034] Figure 6 It is exemplarily shown as Figure 4 The first moving average curve and Figure 5 A graph of the voltage deviation curve, which is the difference between the second moving average curve and the second moving average curve.

[0035] Figure 7 This is an exemplary flowchart illustrating a battery diagnostic method according to a first embodiment of the present disclosure.

[0036] Figure 8 This is an exemplary flowchart of a battery diagnostic method according to a second embodiment of the present disclosure. Detailed Implementation

[0037] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms or words used in the specification and appended claims should not be construed as limited to their general and dictionary meanings, but rather interpreted based on their meanings and concepts corresponding to the technical solutions of the present disclosure, in a manner that allows the inventors to appropriately define the terms for the best illustration.

[0038] Therefore, the embodiments described herein and the examples shown in the accompanying drawings are exemplary embodiments of this disclosure and are not intended to fully describe the technical solutions of this disclosure. It should be understood that various other equivalent substitutions and modifications can be made thereto when submitting an application.

[0039] Terms including ordinal numbers such as “first” and “second” are used to distinguish one element from another among various elements, and are not intended to limit the elements.

[0040] Unless the context clearly indicates otherwise, the term "comprising," as used herein, specifies the presence of the stated element but does not exclude the presence or addition of one or more other elements. Additionally, the term "control circuitry" as used herein refers to at least one processing unit that performs at least one function or operation and may be implemented individually or in combination in hardware and software.

[0041] Furthermore, throughout the specification, it will be further understood that when an element is referred to as being “connected to” another element, it can be directly connected to the other element or there can be an intermediary element.

[0042] Figure 1 A diagram illustrating, by way of example, the components of an electric vehicle according to this disclosure.

[0043] Reference Figure 1 The electric vehicle 1 includes a vehicle controller 2, a battery pack 10, an inverter 30, and an electric motor 40. The charging / discharging terminals P+ and P- of the battery pack 10 can be electrically connected to the charger 3 via a charging cable. The charger 3 can be included in the electric vehicle 1 or can be installed in a charging station.

[0044] The vehicle controller 2 (e.g., an electronic control unit (ECU)) is configured to send a key-on signal to the battery diagnostic device 100 in response to the ignition button (not shown) of the electric vehicle 1 being moved to the OFF position by the user. The vehicle controller 2 is also configured to transmit a key-off signal to the battery diagnostic device 100 in response to the user moving the ignition button to the OFF position. The charger 3 can provide constant current or constant voltage charging power via the charging / discharging terminals P+ and P- of the battery pack 10 through communication with the vehicle controller 2. The charger 3 may have a discharging function and, prior to the first charging phase S1 described below, can discharge the battery 11 in response to a request from the vehicle controller 2, such that the battery voltage (e.g., open-circuit voltage (OCV)) of the battery 11 is equal to or less than a predetermined reference voltage.

[0045] The battery pack 10 includes a battery 11, a relay 20, and a battery diagnostic device 100.

[0046] Battery 11 includes at least one battery cell BC. Figure 1 The diagram shows multiple battery cells BC1~BC1 connected in series as illustrated. N (N is a natural number of 2 or greater) 11 batteries. Multiple battery cells BC1~BC N They can be configured with the same electrical and chemical specifications. In the following text, when referring to multiple battery cells BC1~BC... N In the common description, the battery cell is given the reference numeral "BC".

[0047] The battery cell BC is not limited to a specific type and can include any type of battery cell that can be recharged repeatedly, such as a lithium-ion cell.

[0048] Relay 20 is connected in series to battery 11 by connecting battery 11 to the power path of inverter 30. Figure 1 A relay 20 is shown connected between the positive terminal of battery 11 and the charge / discharge terminal P+. Relay 20 is controlled to open / close in response to a switching signal from battery diagnostic device 100. Relay 20 can be a mechanical contactor that opens and closes by the electromagnetic force of a coil, or a semiconductor switch such as a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0049] Inverter 30 is configured to convert direct current (DC) power from battery 11, included in battery pack 10, into alternating current (AC) power in response to commands from battery diagnostic device 100 or vehicle controller 2. Electric motor 40 operates using AC power from inverter 30. Electric motor 40 may include, for example, a three-phase AC motor. Inverter 30, electric motor 40, and components in electric vehicle 1 supplied by the discharge power of battery 11 can be collectively referred to as electrical loads.

[0050] The battery diagnostic device 100 includes a voltage detector 110 and a control circuit 140. The battery diagnostic device 100 may also include at least one of a current detector 120, a temperature detector 130, and a communication circuit 150.

[0051] Voltage detector 110 is connected to the positive and negative terminals of battery cell BC and is configured to measure the cell voltage across battery cell BC and generate a voltage signal indicating the measured cell voltage. Voltage detector 110 may include at least one of known voltage detection devices such as a voltage measurement integrated circuit IC.

[0052] A current detector 120 is connected in series to the battery 11 via the current path between the battery 11 and the inverter 30. The current detector 120 is configured to measure the battery current (also referred to as the "charge / discharge current") flowing through the battery 11 and generate a current signal indicating the measured battery current. Due to multiple battery cells BC1~BC N Connected in series, flowing through multiple battery cells BC1~BC N The battery current of any one of them is equal to the battery current flowing through the remaining battery cells. The current detector 120 may include at least one of known current detection devices such as a shunt resistor or a Hall effect device.

[0053] Temperature detector 130 is configured to measure the battery temperature of battery 11 and generate a temperature signal indicating the measured battery temperature. Temperature detector 130 may include at least one of known temperature sensing devices such as thermocouples, thermistors, and bimetallic devices.

[0054] The communication circuit 150 is configured to support wired or wireless communication between the control circuit 140 and the vehicle controller 2. Wired communication may be, for example, Controller Area Network (CAN) communication, while wireless communication may be, for example, Zifeng or Bluetooth communication. The communication protocol is not limited to a specific type and may include any type of communication protocol that supports wired / wireless communication between the control circuit 140 and the vehicle controller 2. The communication circuit 150 may include output devices (e.g., a display, a speaker) to provide information received from the control circuit 140 and / or the vehicle controller 2 in a format recognizable by the user (driver).

[0055] The control circuit 140 is operatively connected to the relay 20, the voltage detector 110, and the communication circuit 150. "Operationally connected" means directly or indirectly connected to transmit and receive signals in one or both directions.

[0056] Control circuit 140 may collect voltage signals from voltage detector 110, current signals from current detector 120, and / or temperature signals from temperature detector 130. That is, control circuit 140 may use an analog-to-digital converter (ADC) within control circuit 140 to convert each analog signal collected from voltage detector 110, current detector 120, and temperature detector 130 into a digital value and record that value. Alternatively, each of voltage detector 110, current detector 120, and temperature detector 130 may include its own ADC to send a digital value to control circuit 140.

[0057] The control circuit 140 may also be referred to as a "battery controller" and may be implemented in hardware using at least one of an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a microprocessor, or an electrical unit for performing other functions.

[0058] Memory 141 may include at least one type of storage medium selected from, for example, flash memory, hard disk, solid-state drive (SSD), silicon disk drive (SDD), multimedia card micro, random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), or programmable read-only memory (PROM). Memory 141 may store data and programs required for calculations by control circuit 140. Memory 141 may store data indicating the calculation results of control circuit 140. Memory 141 may store datasets and software used to determine whether battery cell BC is abnormal. Memory 141 may be integrated into control circuit 140.

[0059] When relay 20 is turned on during the operation of inverter 30, electric motor 40, and / or charger 3, battery 11 enters charging mode or discharging mode. When relay 20 is turned off while battery 11 is in charging or discharging mode, battery 11 is switched to sleep mode.

[0060] Control circuit 140 can open relay 20 in response to a start signal. Control circuit 140 can close relay 20 in response to an ignition stop signal. The start signal is a signal requesting a switch from sleep mode to charging or discharging. The ignition stop signal is a signal requesting a switch from charging or discharging to sleep mode. Alternatively, vehicle controller 2 can replace control circuit 140 in controlling the opening / closing of relay 20.

[0061] although Figure 1 A battery diagnostic device 100 included in a battery pack 10 for an electric vehicle 1 is shown, but it should be understood that this is provided for illustrative purposes. That is, the battery diagnostic device 100 can be included in a test system for anomaly screening tests during the production of battery cells BC.

[0062] Figure 2 This is an example of a graph showing the voltage curves corresponding to the original time series of the actual voltage values ​​of the battery cells. Figure 3 This exemplifies how measurement noise is mixed in with... Figure 2 The measured voltage curve is obtained by plotting the original time series corresponding to the voltage curve. Figure 4 This exemplarily illustrates applying a first averaging filter... Figure 3 The voltage curve is used to obtain the first moving average curve graph. Figure 5 This exemplifies the application of a second averaging filter. Figure 3 The voltage curve is used to obtain the second moving average curve graph, and Figure 6 It is exemplarily shown as Figure 4The first moving average curve and Figure 5 A graph of the voltage deviation curve, which is the difference between the second moving average curve and the second moving average curve.

[0063] First, refer to Figure 2 Voltage curve 200 includes the predetermined time period t1~t2. M An example of the original time series of the actual voltage values ​​of battery cell BC during charging. For ease of understanding, the cell voltage increases linearly, and the time periods before value t1 and t2 are omitted. M A graph showing the actual voltage values ​​for the subsequent time period.

[0064] When the battery cell BC is normal, the cell voltage increases slowly during charging. Conversely, when the battery cell BC is abnormal due to internal fault conditions (such as micro-short circuits or torn portions of the electrode connectors), irregular behaviors such as temporary sharp drops or sharp rises in cell voltage may be observed during charging. Figure 2 The voltage curve 200 correlates with anomalies in battery cell BC, with region X indicating the time range of an abnormally sharp drop in cell voltage and region Y indicating the time range of an abnormally sharp rise in cell voltage. Although Figure 2 The cell voltage during charging is shown, but abnormal battery cells may exhibit abnormal voltage changes during discharging or resting. For example, during discharging, the cell voltage of a normal battery cell may decrease slowly, while the cell voltage of an abnormal battery cell may temporarily rise or drop sharply.

[0065] Next, refer to Figure 3 The voltage curve 300 indicates that measurement noise is mixed in. Figure 2 The voltage curve 200 is the result of the actual unit voltage, that is, a time series of multiple voltage values ​​indicating the measured unit voltages, arranged in chronological order. When M is a natural number indicating a predetermined total sample size (e.g., 300) and K is a natural number of M or less, t K It is the Kth voltage value V in time sequence among the total M voltage values ​​included in voltage curve 300. m The measurement time of [K] (the Kth measurement time t) K And two adjacent measurement moments are time intervals corresponding to a predetermined sampling time (e.g., 0.1 seconds). Voltage value V m [K] is the index to measurement time t among the total M voltage values ​​included in voltage curve 300. K Data points.

[0066] Measurement noise may occur irregularly due to internal / external factors of the voltage detector 110 (such as temperature, sampling rate, and electromagnetic waves from the voltage measuring device). The current curve 310 includes the predetermined time period t1~t2. M The time series of battery current values ​​measured internally. For ease of description, the attached figure shows the battery current during a predetermined time period t1~t2. M The internal state is constant.

[0067] When Figure 3 Voltage curve 300 and Figure 2 When comparing the voltage curve 200, from Figure 2 Abnormal behaviors X and Y are easily identified in the voltage curve 200 without measured noise, and are observed throughout the predetermined time period t1~t2. M Internal noise measurement Figure 3 The voltage curve 300 makes it difficult to identify abnormal behaviors X and Y.

[0068] The inventors discovered that the above-mentioned problem has been solved by applying a first averaging filter and a second averaging filter to the voltage curve 300, which includes measurement noise occurring at the measurement moment of the cell voltage. The time series of voltage values ​​of the target battery cell BC acquired over a predetermined past period can be referred to as the "reference voltage curve," and the time series of current values ​​can be referred to as the "reference current curve." The following description is made under the assumption that the voltage curve 300 and the current curve 310 are the reference voltage curve and the reference current curve, respectively.

[0069] First, the control circuit 140 can determine multiple sub-voltage curves by applying a moving window of a first time length to the reference voltage curve 300. Further, the control circuit 140 can determine multiple sub-current curves that have a one-to-one correspondence with the multiple sub-voltage curves by applying a moving window of the first time length to the reference current curve 310.

[0070] When K is a natural number of M or less, a total of M sub-voltage curves (i.e., the first to the Mth sub-voltage curves) can be determined from the reference voltage curve 300. The reference voltage curve 300 includes a total of M voltage values ​​(i.e., the first to the Mth voltage values) measured sequentially at each sampling time W. As a subset of the reference voltage curve 300, the sub-voltage curves S K This includes (A / W+1) consecutive voltage values ​​in chronological order. In the example where the sampling time W = 0.1 seconds and the first time length A = 10 seconds, the sub-voltage curve S... K It is a time series of a total of 101 voltage values ​​from the (KP)th voltage value to the (K+P)th voltage value. P=A / 2W=50.

[0071] exist Figure 3 In the middle, R K It is related to the sub-voltage curve S K The relevant sub-current curve. Therefore, the sub-current curve R K It can also include (A / W+1) consecutive data points (current values) in chronological order.

[0072] When the battery current changes significantly, the cell voltage also changes significantly. This rapid change in cell voltage caused by the battery current is a factor that prevents the identification of abnormal cell voltage behavior from the reference voltage curve 300. Therefore, the control circuit 140 can adjust the sub-current curve R... K Under the condition that the current change is equal to or less than the threshold change, for the sub-voltage curve S K Perform the following calculations. Sub-current curve R K The change in current can be represented by the sub-current curve R. K The difference between the maximum and minimum current values. This disclosure is suitable for diagnosing abnormalities in battery cells from time series of cell voltages measured during constant current charging or dormancy (e.g., during periods of small variation in battery current).

[0073] Reference Figure 4 The first average voltage curve 400 is obtained by applying a first averaging filter of a first time length A to the reference voltage curve 300. The first averaging filter may be a low-pass filter (e.g., a center-moving average with a subset size (A / W+1) corresponding to the first time length A). In the example, the control circuit 140 calculates the values ​​included in the sub-voltage curve S. K The index to measurement time t is determined by the average of the (A / W+1) voltage values ​​(i.e., the voltage values ​​from the (KP)th to the (K-1)th, the Kth, and the (K+1)th to the (K+P)th voltage values). K Long-term average voltage value V av1 [K]. Equation 1 below represents the first averaging filter.

[0074] Equation 1

[0075] In equation 1, V m [i] is the i-th voltage value included in the reference voltage curve 300, A is the first time length, W is the sampling time, P = A / 2W, and V av1 [K] is at the measurement time t K The long-term average voltage value. Control circuit 140 can determine this by substituting 1 to M into K in Equation 1. Figure 4The first average voltage curve is 400. The first time length A is preset to be an integer multiple of the sampling time W. Therefore, the first time length A indicates the value of the long-term average voltage V used to calculate the voltage. av1 The size of the subset of [K] is (A / W+1).

[0076] Reference Figure 5 A second average voltage curve 500 is obtained by applying a second averaging filter, which is shorter than the first time length A, to the reference voltage curve 300. The second averaging filter can be a low-pass filter (e.g., a center-moving average with a subset size B / W+1 corresponding to the second time length B). In this example, the control circuit 140 calculates the values ​​included in the sub-voltage curve S... K The average of the (B / W+1)th voltage values ​​(i.e., the voltage values ​​from (KQ)th to (K-1), the Kth voltage value, and the voltage values ​​from (K+1)th to (K+Q)th voltage values) is used to determine the index to the measurement time t. K short-term average voltage value V av2 [K]. Q = B / 2W. Short-term average voltage value V av2 [K] is the sub-voltage curve S K subset U K The average value of subset U. K In the sub-voltage curve S K Within a time range, it has the same time range t K-P ~ t K+P Same center t K Time range t K-Q ~ t K+Q The voltage curve. Equation 2 below represents the second averaging filter.

[0077] Equation 2

[0078] In equation 2, V m [i] is the i-th voltage value included in the reference voltage curve 300, B is the second time length, W is the sampling time, Q = B / 2W, and V av2 [K] is at the measurement time t K The short-term average voltage value. Control circuit 140 can determine this by substituting 1 to M one by one into K in equation 2. Figure 5 The second average voltage curve is 500. The second time length B is preset to be an integer multiple of the sampling time W. Therefore, the second time length B indicates the value of the short-term average voltage V used to calculate the voltage. av2 The size of the subset of [K] (B / W+1).

[0079] If the first time length A is greater than the second time length B, each data point of the first average voltage curve 400 (i.e., the long-term average voltage value) can be called the "long-term average value," and each data point of the second average voltage curve 500 (i.e., the short-term average voltage value) can be called the "short-term average value." In the example, A can be ten times larger than B.

[0080] Reference Figure 6 The voltage deviation curve 600 is the result of subtracting one of the first average voltage curve 400 and the second average voltage curve 500. That is, the voltage deviation curve 600 is the result of subtracting one of the two average voltage curves for a predetermined time period t1~t2. M The time series of a total of M voltage deviations. And the sub-voltage curve S K The relevant voltage deviation ΔV[K] is obtained from the long-term average voltage value V av1 [K] and short-term average voltage value V av2 The value is calculated by subtracting one from the other in [K]. In the example, ΔV[K] = V av2 [K]-V av1 [K]

[0081] As mentioned above, the long-term average voltage value V av1 [K] is relative to the measurement time t. K The long-term average cell voltage of the first time length A, and the short-term average voltage value V. av2 [K] is relative to the measurement time t. K The short-term average cell voltage of the second time length B. Therefore, when the voltage is obtained from the long-term average voltage value V... av1 [K] and short-term average voltage value V av2 When calculating the voltage deviation ΔV[K] by subtracting one from the other in [K], it is possible to effectively remove the voltage deviation relative to the measurement time t. K Measurement noise generated within the predetermined time period.

[0082] By using the long-term average voltage value V av1 [K] and short-term average voltage value V av2 The process of subtracting one from the other in [K] can alleviate the effects of time t relative to the measurement time to a considerable extent. K Measurement noise generated within the predetermined time period.

[0083] The control circuit 140 can compare the voltage deviation ΔV[K] with a first deviation threshold TH1 and a second deviation threshold TH2. The first deviation threshold TH1 can be a predetermined positive number (e.g., +0.001V), and the second deviation threshold TH2 can be a predetermined negative number (e.g., -0.001V) whose absolute value is equal to the first deviation threshold TH1.

[0084] When a predetermined number (e.g., 10) or more of the voltage deviations included in the voltage deviation curve 600 are equal to or greater than the first deviation threshold TH1 or equal to or less than the second deviation threshold TH2, the control circuit 140 can determine that the battery cell BC is abnormal.

[0085] When any two of the total M voltage deviations included in the voltage deviation curve 600 meet the first, second, and third requirements, the control circuit 140 can determine that the battery cell BC is abnormal. The first requirement is met when one of the two voltage deviations is equal to or greater than the first deviation threshold TH1. The second requirement is met when the other of the two voltage deviations is equal to or less than the second deviation threshold TH2. The third requirement is met when the time interval between the two voltage deviations is equal to or less than a threshold time. The threshold time can be preset to be less than a first time length A. (Refer to...) Figure 6 The voltage deviation ΔV[a] is equal to or less than the second deviation threshold TH2 (satisfying the second requirement), and the voltage deviation ΔV[b] is equal to or greater than the first deviation threshold TH1 (satisfying the first requirement). Therefore, when the time interval Δt between the two voltage deviations ΔV[a] and ΔV[b] is t b - t a When the time is equal to or less than the threshold, the battery cell BC is determined to be abnormal.

[0086] Figure 7 This is an exemplary flowchart illustrating a battery diagnostic method according to a first embodiment of the present disclosure.

[0087] Reference Figures 1 to 7 In step S710, the control circuit 140 determines multiple sub-voltage curves by applying a moving window of the first time length A to the reference voltage curve 300. The reference voltage curve 300 indicates the voltage for a predetermined time period t1~t2. M A time series of multiple voltage values ​​of the cell voltage of battery cell BC measured at each sampling time.

[0088] In step S720, the control circuit 140 determines the relationship between each sub-voltage curve S K The relevant voltage deviation ΔV[K]. Step S720 may include sub-steps S722, S724, and S726.

[0089] In step S722, the control circuit 140 uses a first averaging filter with a first time length A to determine the sub-voltage curve S. K Long-term average voltage value V av1 [K] (see Equation 1).

[0090] In step S724, the control circuit 140 uses a second averaging filter with a second time length B to determine the sub-voltage curve S.K short-term average voltage value V av2 [K] (see Equation 2).

[0091] In step S726, the control circuit 140 obtains the long-term average voltage value V av1 [K] and short-term average voltage value V av2 The voltage deviation ΔV[K] is determined by subtracting one of the values ​​from the other in [K].

[0092] In step S730, the control circuit 140 determines whether the battery cell BC is abnormal by comparing each of the plurality of voltage deviations determined for the plurality of sub-voltage curves with at least one of a first deviation threshold and a second deviation threshold. When the value of step S730 is "yes", step S740 is executed.

[0093] In step S740, the control circuit 140 generates a diagnostic message notifying the battery cell BC of an abnormality. The diagnostic message can be transmitted wired / wirelessly via the vehicle controller 2 and / or the user device.

[0094] Figure 8 This is an exemplary flowchart of a battery diagnostic method according to a second embodiment of the present disclosure.

[0095] Reference Figures 1 to 6 and Figure 8 In step S800, the control circuit 140 determines multiple sub-current curves by applying a moving window of the first time length A to the reference current curve 310. The reference current curve 310 indicates the sub-current curves for a predetermined time period t1~t2. M A time series of multiple current values ​​of the battery current of battery cell BC measured at each sampling time.

[0096] In step S810, the control circuit 140 determines multiple sub-voltage curves by applying a moving window of the first time length A to the reference voltage curve 300. Step S810 is the same as step S710.

[0097] In step S812, the control circuit 140 determines each sub-current curve R. K The change in current.

[0098] In step S820, the control circuit 140 determines each sub-current curve R among the plurality of sub-voltage curves whose current change is equal to or less than a threshold change. K The relevant sub-voltage curve S K The voltage deviation ΔV[K]. Step S820 may include... Figure 7 Steps S722, S724, and S726.

[0099] In step S830, the control circuit 140 determines whether the battery cell BC is abnormal by comparing each voltage deviation determined in step S820 with at least one of a first deviation threshold and a second deviation threshold. When the value of step S830 is "yes", step S840 is executed.

[0100] In step S840, the control circuit 140 generates a diagnostic message notifying the battery cell BC of an abnormality.

[0101] The embodiments of this disclosure described above can be implemented not only by devices and methods, but also by a program that performs functions corresponding to the configuration of the embodiments of this disclosure or by a recording medium containing the program, and such implementation can be easily carried out by those skilled in the art through the disclosure of the above embodiments.

[0102] Although the present disclosure has been described above with reference to a limited number of embodiments and accompanying drawings, the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various modifications and alterations can be made within the scope of the technical aspects of the present disclosure and the appended claims and their equivalents.

[0103] Furthermore, since those skilled in the art can make many substitutions, modifications and alterations to the above-described disclosure without departing from the technical aspects of this disclosure, this disclosure is not limited to the above embodiments and drawings, and all or some embodiments may be selectively combined to allow for various modifications.

[0104] Explanation of reference numerals in the attached figures

[0105] 1: Electric vehicle 2: Vehicle controller

[0106] 10: Battery pack 11: Battery BC: Battery cell

[0107] 100: Battery diagnostic equipment

[0108] 110: Voltage detector; 120: Current detector

[0109] 140: Control Circuit

Claims

1. A battery controller, the battery controller comprising: A memory, on which a program for battery diagnostics is stored; as well as A processor configured to execute the program for battery diagnostics. When the processor executes the program for battery diagnostics, the processor is configured to: The long-term average voltage value and the short-term average voltage value are determined by applying a first averaging filter of a first time length and a second averaging filter of a second time length to the voltage value indicating the cell voltage of the battery cell, wherein the second time length is shorter than the first time length. Determine the voltage deviation, which is the difference between the long-term average voltage value and the short-term average voltage value; as well as The abnormality of the battery cell is determined by comparing the voltage deviation with at least one of a first deviation threshold or a second deviation threshold.

2. The battery controller according to claim 1, in, The first deviation threshold is a positive number, and Wherein, the second deviation threshold is a negative number whose absolute value is equal to the first deviation threshold.

3. The battery controller according to claim 1, in, The processor is configured to: When the voltage deviation is greater than the first deviation threshold or less than the second deviation threshold, the battery cell is determined to be abnormal.

4. The battery controller according to claim 1, in, The processor is configured to: The current change is determined as the difference between the maximum and minimum current values ​​among current values ​​indicating the current of the battery cell measured within the same time period as the cell voltage. Under the condition that the current change is less than the threshold change, the long-term average voltage value and the short-term average voltage value are determined.

5. A battery pack comprising a battery controller according to any one of claims 1 to 4.

6. An electric vehicle comprising the battery pack according to claim 5.

7. A battery diagnostic method, the battery diagnostic method comprising the following steps: The long-term average voltage value and the short-term average voltage value are determined by applying a first averaging filter of a first time length and a second averaging filter of a second time length to the voltage value indicating the cell voltage of the battery cell, wherein the second time length is shorter than the first time length; Determine the voltage deviation, which is the difference between the long-term average voltage value and the short-term average voltage value; as well as The abnormality of the battery cell is determined by comparing the voltage deviation with at least one of a first deviation threshold or a second deviation threshold.

8. The battery diagnostic method according to claim 7, in, The steps to determine whether the battery cell is malfunctioning include the following: When the voltage deviation is greater than the first deviation threshold or less than the second deviation threshold, the battery cell is determined to be abnormal.

9. The battery diagnostic method according to claim 7, further comprising the following steps: The current change is determined as the difference between the maximum and minimum current values ​​among current values ​​indicating the current of the battery cell measured within the same time period as the cell voltage. Specifically, under the condition that the current change is less than the threshold change, the long-term average voltage value and the short-term average voltage value are determined.

10. A recording medium storing a program for battery diagnostics, the program for battery diagnostics being configured to cause a processor to perform the following operations: The long-term average voltage value and the short-term average voltage value are determined by applying a first averaging filter of a first time length and a second averaging filter of a second time length to the voltage value indicating the cell voltage of the battery cell, wherein the second time length is shorter than the first time length; Determine the voltage deviation, which is the difference between the long-term average voltage value and the short-term average voltage value; as well as The abnormality of the battery cell is determined by comparing the voltage deviation with at least one of a first deviation threshold or a second deviation threshold.

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