Battery monitoring method and device

Abstract

To provide a battery monitoring method and a device capable of increasing reliability of monitoring information on a battery state using a current value having undergone linearity compensation and temperature compensation.SOLUTION: The present invention is a method performed by a battery monitoring device, comprising: measuring a first voltage drop across a first shunt resistor of a bus bar electrically connected to a battery, and a second voltage drop across a second shunt resistor in a parallel or series relation with the first shunt resistor; calculating a first current and a second current respectively flowing through the first shunt resistor and the second shunt resistor, using a first voltage drop value and a second voltage drop value; and determining a state of the battery using a difference between a first current value and a second current value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for monitoring a battery, and more particularly to a method and apparatus for measuring currents input to and output from a battery using a shunt resistor and monitoring the state of the battery using the measured currents. [Background technology]

[0002] A shunt resistor is a resistor with a very small resistance that is mainly used for current measurement. Compared to a Hall sensor, which uses the magnetic field generated when current flows through a conductor, current measurement using a shunt resistor is characterized by its low cost and high accuracy.

[0003] The ammeter equipped with the coil includes a shunt resistor connected in parallel inside, and the ammeter connected in series to the terminal formed by cutting the conductor can measure the current flowing in the conductor using the strength of the magnetic field formed in the coil and the value of the current flowing in the shunt resistor.

[0004] When a shunt resistor is inserted between the wires, the voltage across the shunt resistor is measured, and the current value is calculated from the measured voltage according to Ohm's law.

[0005] The current flowing through the terminals connected to the battery is a current resulting from the discharge or charge of the battery, and is used as an index for calculating the remaining capacity or charge capacity of the battery, so accurate measurement of the current value is required.

[0006] For stable current sensing of batteries, e.g., electric vehicle batteries, redundancy is possible using two or more resistors. However, if the difference between the current values ​​measured for redundancy verification falls outside the error range, it can cause problems in determining the battery state. Furthermore, as the current conduction time and current value increase, the battery temperature rises and the error range also increases, so current measurement that can accurately indicate the actual chemical state of the battery is required.

[0007] As a technology related to the present disclosure, a current measuring device using a shunt resistor disclosed in a Korean patent publication discloses a current measuring device including a bus bar, a shunt resistor, and a measuring unit. While this related technology merely uses switches to control the operation of multiple measuring units, the present disclosure is distinguished in its configuration and effects in that it can measure current values ​​with high accuracy by reducing measurement errors through linearity compensation and temperature compensation for the difference between two or more current values ​​measured by the measuring units. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent No. 10-1998091 (Announced on July 9, 2019) Summary of the Invention [Problem to be solved by the invention]

[0009] One problem to be solved by the present disclosure is to provide a current measurement method and device for measuring a current flowing through a bus bar through a shunt resistor.

[0010] One problem to be solved by the present disclosure is to provide a current measurement method and apparatus that can reduce measurement errors through linearity compensation and temperature compensation.

[0011] One problem to be solved by the present disclosure is to provide a current measurement method and apparatus that enables temperature compensation for current measurements through busbar temperature prediction at high temperatures.

[0012] The problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0013] A dual-redundancy design according to one embodiment of the present invention is a battery monitoring device that uses shunt resistors with two resistance values ​​on one bus bar and has two independent analog-to-digital converters (ADCs). The battery monitoring device senses rapidly changing currents, compares the two current values, and transmits a warning message to a higher-level system if the error between the two current values ​​exceeds a set value. The number of shunt resistors is not limited to two, and the technical concept of the present invention can be similarly applied to cases where one bus bar has multiple shunt resistors.

[0014] The battery monitoring device has an isolated voltage converter for use in high voltage applications and is characterized by including a digital isolated converter for communication.

[0015] The two shunt resistors allow for various changes such as 1:1, 2:1, 0.75:1 as needed to determine the optimum current value as well as verifying the current value within the current sensor. In addition, if necessary, one shunt resistor can be combined with other measurement methods such as a Hall sensor or magnetoresistive sensor, and this has the advantage of being able to verify the value independently within the current sensor.

[0016] Conventionally, when switching is performed using a single analog-to-digital converter, it is difficult to simultaneously measure rapidly changing current values, and the comparison function for verifying current values ​​has a problem with time differences in current values, resulting in unnecessary diagnosis due to differences in current values ​​even though the actual current values ​​are the same.

[0017] To solve this problem, two independent analog-to-digital converters (ADCs) are used, and a separate compensation algorithm is also used to ensure their independence and synchronize the measurement time, strengthening the current value verification function. The number of analog-to-digital converters (ADCs) is not limited to two. Shunt resistors are sensitive to temperature, so a temperature sensor must be used, but this temperature sensor is unable to measure the actual temperature of the shunt resistor that rises due to high current, so a temperature prediction algorithm is required. This temperature prediction algorithm predicts the temperature based on factors such as the current magnitude, current conduction time, external temperature, and shunt resistance value.

[0018] The synchronization algorithm involves comparing the measured value with the high-speed converter value when the value is measured using a low-speed converter, and if the measured value is output as a high-speed value, the current value can be identified at high speed and the current value can be verified.

[0019] The battery monitoring device is also characterized by having a rolling count (RC) and a communication error check function (CRC: Cyclic Redundancy Check) to detect communication leaks and errors.

[0020] To achieve the above-mentioned objects, according to one embodiment of the technical concept of the present invention, a battery monitoring method is disclosed, which is performed by a battery monitoring device and includes the steps of measuring a first voltage drop across a first shunt resistor of a bus bar electrically connected to a battery and a second voltage drop across a second shunt resistor connected in parallel or series to the first shunt resistor; calculating a first current and a second current flowing through the first shunt resistor and the second shunt resistor, respectively, using the first voltage drop value and the second voltage drop value; and determining a battery state using a difference between the first current value and the second current value.

[0021] In addition, the battery monitoring method may be configured such that the step of calculating the first and second currents includes the steps of converting the first and second voltage drop values ​​into digital values; calculating the first and second current values ​​by applying calibration data for the first and second shunt resistors to the first and second voltage drop values; and amplifying the first and second current values.

[0022] The battery monitoring method may further include measuring a temperature according to the current using a temperature sensor.

[0023] Furthermore, the battery monitoring method may be configured such that the temperature sensor includes an internal temperature sensor that measures a first temperature value of the bus bar and an external temperature sensor that measures a second temperature value of a PCB on which the bus bar is provided, and the step of measuring the temperatures includes the step of applying weights to the first temperature value and the second temperature value, respectively.

[0024] In addition, the battery monitoring method may further include a step of performing linearity compensation on the first current value and the second current value using linearity data including a temperature value, inflection point information between the first current value and the second current value, an amplification value of the first current value and the second current value, and a predicted temperature increase value due to the current.

[0025] The battery monitoring method is characterized in that the step of performing linearity compensation includes compensating for linearity for each current section due to an inflection point according to an amplification factor of the first current and the second current.

[0026] The battery monitoring method may further include performing synchronization and temperature compensation on the first and second current values ​​that change rapidly according to a change in temperature.

[0027] In addition, the battery monitoring method may be configured such that the step of performing synchronization and temperature compensation includes a step of determining a temperature prediction variable based on the magnitudes of the first current value and the second current value and a current application time, a step of calculating a temperature prediction variable value based on the temperature prediction variable, and a step of performing temperature compensation on the first current value and the second current value using the temperature prediction variable value.

[0028] To achieve the above objects, one embodiment of the present invention provides a battery monitoring device including: a voltage measurement unit that measures a first voltage drop across a first shunt resistor of a bus bar electrically connected to a battery and a second voltage drop across a second shunt resistor that is connected in parallel or series to the first shunt resistor; a current calculation unit that calculates a first current and a second current that flow through the first shunt resistor and the second shunt resistor, respectively, using the first and second voltage drop values; a temperature measurement unit that measures temperature changes due to the first and second currents using a temperature sensor; and a control unit that determines a battery state using a difference between the first and second current values ​​calculated through linearity compensation, synchronization, and temperature compensation based on element characteristics for the first and second current values.

[0029] The battery monitoring device may further include a linearity compensator that compensates for linearity for each current section based on an inflection point according to an amplification factor of the first current and the second current.

[0030] The battery monitoring device may further include a temperature compensation unit that determines a temperature prediction variable based on the magnitude of the first current value and the second current value and the current application time, and performs temperature compensation on the first current value and the second current value using a temperature prediction variable value calculated based on the temperature prediction variable.

[0031] The battery monitoring device may further include a battery status determination unit that determines an error based on the range of the difference value and diagnoses the battery status based on the number of times the error occurs.

[0032] Specific details of other embodiments are included in the "Specific Contents for Carrying Out the Invention" and the accompanying "Drawings."

[0033] The advantages and / or features of the present invention and the manner in which they are achieved will become more apparent with reference to the various embodiments described in detail below in conjunction with the accompanying drawings.

[0034] However, it should be understood that the present invention is not limited to the configuration of each embodiment disclosed below, but may be embodied in various different forms, and that each embodiment disclosed in this specification is provided merely to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the present invention, and that the present invention is defined only by the scope of each claim in the claims. [Effects of the Invention]

[0035] According to the present invention, the measurement error of the current value can be reduced through linearity compensation and temperature compensation. In addition, the reliability of monitoring information regarding the battery state can be improved by using a current value that has undergone linearity compensation and temperature compensation.

[0036] The effects of the battery monitoring method and apparatus according to the technical idea of ​​the present invention are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawings]

[0037] [Figure 1] 2 is a diagram illustrating a schematic example of a bus bar included in a battery monitoring device according to an embodiment of the present invention. [Figure 2] 1 is a block diagram of a battery monitoring device according to an embodiment of the present invention; [Figure 3] 2 is a block diagram of a measurement unit included in a battery monitoring device according to an embodiment of the present invention. [Figure 4] 3 is a flowchart of a battery monitoring method according to an embodiment of the present invention. [Figure 5] 5 is a detailed flowchart of step S150 in FIG. 4. [Figure 6] FIG. 10 illustrates an example of linearity compensation according to an embodiment of the present invention. [Figure 7] 5 is a detailed flowchart of step S170 in FIG. 4. [Figure 8] 5 is a detailed flowchart of step S180 in FIG. 4. [Figure 9] FIG. 10 illustrates an example of temperature compensation according to one embodiment of the present invention. [Figure 10] FIG. 10 illustrates an example before temperature compensation according to one embodiment of the present invention. [Figure 11] FIG. 10 illustrates an example after temperature compensation according to one embodiment of the present invention. [Figure 12] 5 is a detailed flowchart of step S190 in FIG. 4. [Figure 13] 10A and 10B are diagrams illustrating an example of a comparison between before and after compensation according to an embodiment of the present invention. [Figure 14] FIG. 10 illustrates an example of accuracy and linearity with compensation according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] Before describing the present invention in detail, it should be understood that the terms and words used in this specification should not be interpreted unconditionally and limited to their ordinary or dictionary meanings, but rather that the inventor of the present invention may appropriately define and use the concepts of various terms in order to explain his / her invention in the best possible way, and further, that these terms and words should be interpreted as meanings and concepts that correspond to the technical idea of ​​the present invention.

[0039] In other words, it should be understood that the terms used in this specification are used to describe preferred embodiments of the present invention and are not intended to specifically limit the content of the present invention, but rather are terms defined in consideration of various possibilities of the present invention.

[0040] Furthermore, it should be understood that in this specification, singular expressions can include plural expressions unless the context clearly indicates a different meaning, and that even if similar expressions are used in the plural, they can also include the meaning of the singular.

[0041] Throughout this specification, when a component is described as "comprising" other components, unless otherwise specified to the contrary, this does not mean that it excludes any other components, but that it may also include any other components.

[0042] Furthermore, when a component is described as being "inside or connected to" another component, it should be understood that this component may be directly connected to the other component, be in contact with the other component, or be spaced apart at a certain distance. In the case where the component is spaced apart at a certain distance, a third component or means may be present to fix or connect the component to the other component, and the description of this third component or means may be omitted.

[0043] On the other hand, when an element is described as being "directly coupled" or "directly connected" to another element, it should be understood that there is no third element or means present.

[0044] Similarly, other expressions describing the relationship between components, such as "between" and "immediately between," or "adjacent to" and "directly adjacent to," must be analyzed as having the same intent.

[0045] Furthermore, in this specification, terms such as "one side," "other side," "one side," "other side," "first," and "second," if used, are used to clearly distinguish one component from other components, and it should be understood that such terms are not used to limit the meaning of the components in question.

[0046] Furthermore, in this specification, when terms related to positions such as "upper," "lower," "left," and "right" are used, they should be understood to indicate the relative positions of the components in the drawings, and should not be understood to refer to absolute positions, unless absolute positions are specified for these positions.

[0047] Furthermore, in this specification, when specifying the reference numerals for each component in each drawing, the same component has the same reference numeral even if the component appears in another drawing, i.e., the same reference numeral indicates the same component throughout the specification.

[0048] In the accompanying drawings of this specification, the size, position, connection relationship, etc. of each component constituting the present invention may be partially exaggerated, reduced, or omitted in order to sufficiently and clearly convey the concept of the present invention or for the convenience of explanation, and therefore the proportions and scales may not be strictly adhered to.

[0049] Furthermore, in the following description of the present invention, detailed descriptions of configurations that are deemed to be likely to obscure the gist of the present invention, such as publicly known technologies including conventional technologies, may be omitted.

[0050] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic example of a bus bar included in a battery monitoring device according to an embodiment of the present invention. 1, the bus bar 100 may be configured to include a conductor 110, a shunt resistor 120, a sensing pin 130, and a hole 140. The bus bar 100 may be configured in a form in which a plurality of shunt resistors 120, for example, two or more shunt resistors 120 and the conductor 110 are alternately connected. In this embodiment, two shunt resistors 120 are described as being provided, but the present invention is not limited to this. In addition, the battery monitoring device of the present invention may be manufactured as a module and used in various electronic devices.

[0051] Sensing pins 130 are disposed on both ends of the shunt resistor 120. Two selected sensing pins 130 are connected to a positive terminal and a negative terminal of a voltmeter, respectively.

[0052] Holes 140 connected to a battery and a circuit are formed at both ends of the bus bar 100. A secondary battery is connected through the holes 140.

[0053] The bus bar 100 is not limited to a linear shape. JPEG2025164914000002.jpg629, and multiple shunt resistors can be connected in series or in parallel to form a circuit.

[0054] The shunt resistor 120 can be implemented using a copper alloy, for example, manganin, which is an alloy of copper, manganese, and nickel. The shunt resistor 120 has a relatively small resistance, but the current value is calculated by measuring the voltage value between the sensing pins 130 on both ends of the shunt resistor 120.

[0055] FIG. 2 is a block diagram of a battery monitoring device according to an embodiment of the present invention. 2, a battery monitoring device 10 according to an embodiment of the present invention may be configured to include a bus bar 100, a measuring unit 200, a first temperature sensor 310, and a second temperature sensor 320. The measuring unit 200 is electrically connected to sensing pins 130 disposed on both ends of a shunt resistor 120 included in the bus bar 100.

[0056] The bus bar 100 functions to form a plurality of voltage drops across the shunt resistors 120 using shunt resistors 120 connected in series or parallel. The measuring unit 200 is electrically connected to sensing pins 130 formed on both ends of the shunt resistors 120.

[0057] The measuring unit 200 measures multiple voltage drops, calculates and compensates for current based on the measured voltage drops, and outputs accurate current values ​​when the battery is discharged and charged. The measuring unit 200 also monitors the battery status based on the current values. Battery monitoring includes predicting the battery life and state of charge (SOC) and determining whether the battery is in a normal state.

[0058] The first temperature sensor 310, also referred to as an internal sensor, is provided on the busbar 100 and has the function of sensing the temperature of the busbar 100, i.e., a first temperature value. The second temperature sensor 320, also referred to as an external sensor, is provided on a circuit board (PCB) on which the busbar 100 is provided and has the function of sensing the temperature of the circuit board, i.e., a second temperature value.

[0059] The measuring unit 200 is electrically connected to the first temperature sensor 310 and the second temperature sensor 320 to receive the first and second temperature values.

[0060] FIG. 3 is a block diagram of a measurement unit included in a battery monitoring device according to an embodiment of the present invention. Referring to FIG. 3, the measurement unit 200 included in the battery monitoring device 10 according to one embodiment of the present invention may be configured to include a control unit 210, a voltage measurement unit 220, a current calculation unit 230, a temperature measurement unit 240, a current compensation unit 250, and a battery state determination unit 280.

[0061] The voltage measurement unit 220 has a function of measuring a first voltage drop across a first shunt resistor of a bus bar electrically connected to the battery, and a second voltage drop across a second shunt resistor in a parallel or series relationship with the first shunt resistor.

[0062] The current calculation unit 230 has a function of calculating the first current and the second current flowing through the first shunt resistor and the second shunt resistor, respectively, using the first voltage drop value and the second voltage drop value.

[0063] The temperature measurement unit 240 has a function of measuring a temperature change of the shunt resistor 120 due to a first current and a second current using the first temperature sensor 310 and the second temperature sensor 320. The temperature measurement unit 240 receives the first temperature value and the second temperature value from the first temperature sensor 310 and the second temperature sensor 320, respectively, converts these values ​​into digital values, and applies weighting values ​​to the digital first temperature value and second temperature value to output a shunt resistor temperature value. The shunt resistor temperature value is used for linearity compensation and temperature compensation of the current value.

[0064] The control unit 210 has a function of determining the state of the battery using a difference between the first and second current values ​​calculated through linearity compensation according to device characteristics, synchronization, and temperature compensation for the first and second current values. The control unit 210 compares measurement times of the first and second voltage drop values ​​prior to temperature compensation, and if the measurement times of the two values ​​are different, controls the voltage measurement unit 220 to make the measurement times of both values ​​the same based on one of the measurement times.

[0065] The linearity compensator 260 compensates for linearity for each current section corresponding to an inflection point according to the amplification factor of the first and second currents. For example, if the first current value contains an error compared to an abnormal value, the error ratio will appear discontinuously on the graph due to the nonlinearity of the device. When linearity compensation is performed on such an error ratio, the error ratio will be distributed continuously.

[0066] The temperature compensator 270 determines a temperature prediction variable based on the magnitude of the first and second current values ​​and the current application time, and performs temperature compensation on the first and second current values ​​using the temperature prediction variable value calculated based on the temperature prediction variable. The reason for performing temperature compensation on the current value is that the temperature measurement speed using a temperature sensor cannot keep up with the temperature rise speed. A temperature compensation process is necessary to measure a temperature that changes rapidly.

[0067] The battery status determination unit 280 has a function of determining an error based on the range of the difference value and diagnosing the battery status based on the number of errors that occur. Whether the battery status is normal or abnormal is determined based on the difference between the first current value and the second current value. For example, if the difference between the first current value and the second current value calculated through linearity compensation and temperature compensation is outside a predetermined critical value or the critical number of times, it is highly likely that the battery is not in a normal state. The battery monitoring method (step S100) performed by the battery monitoring device 10 will now be described.

[0068] FIG. 4 is a flowchart of a battery monitoring method according to one embodiment of the present invention. Referring to FIG. 4, the battery monitoring method (step S100) can be configured to include voltage drop measurement (step S110), temperature measurement (step S120), current calculation (step S130), current value compensation (step S140), and battery state determination (step S190).

[0069] First, the battery monitoring device 10 can measure a first voltage drop across a first shunt resistor of a bus bar electrically connected to the battery and a second voltage drop across a second shunt resistor in a parallel or series relationship with the first shunt resistor (step S110).

[0070] The battery monitoring device 10 can measure the temperature according to the current using the temperature sensor 300 (step S120).

[0071] The temperature sensor 300 includes a first temperature sensor 310 that measures a first temperature value of the busbar and a second temperature sensor 320 that measures a second temperature value of the PCB on which the busbar 100 is provided, and the step of measuring the temperature (step S120) may be configured to include a step of applying a weight to each of the first temperature value and the second temperature value. Because the value of the current flowing through the shunt resistor 120 is affected in a composite manner by the temperature of the busbar 100 and the temperature of the PCB to which the busbar 100 is connected, the weight to be applied to the first temperature value and the weight to be applied to the second temperature value are determined depending on the connection relationship, shape, and size of the busbar 100 and the PCB.

[0072] Next, the battery monitoring device 10 may calculate a first current and a second current flowing through the first shunt resistor 121 and the second shunt resistor 122, respectively, using the first voltage drop value and the second voltage drop value (step S130). The calculation of the current values ​​is based on Ohm's law, but shunt resistor calibration data including discontinuity or inflection point information is used.

[0073] For example, the battery monitoring device 10 may convert the first voltage drop value and the second voltage drop value into digital values ​​(step S131), apply the calibration data of the first shunt resistor and the calibration data of the second shunt resistor to the first voltage drop value and the second voltage drop value to calculate the first current value and the second current value (step S132), and then amplify the first current value and the second current value (step S133).

[0074] Next, the battery monitoring device 10 can perform various compensations for the first current value and the second current value (step S140).

[0075] For example, the battery monitoring device 10 can perform linear compensation on the first current value and the second current value using linear data including the temperature value, inflection point information between the first current value and the second current value, amplification values ​​of the first current value and the second current value, and a predicted temperature increase value due to the current (step S150).

[0076] The linearity compensation (step S150) is characterized by compensating for linearity for each current section based on an inflection point according to the amplification factor of the first current and the second current.

[0077] Furthermore, the battery monitoring device 10 can perform synchronization and temperature compensation for the first and second current values ​​that change rapidly according to changes in temperature (steps S170 and S180).

[0078] For example, the battery monitoring device 10 determines a temperature prediction variable based on the magnitude of the first current value and the second current value and the current application time, calculates a temperature prediction variable value based on the temperature prediction variable, and can perform temperature compensation for the first current value and the second current value using the temperature prediction variable value.

[0079] Finally, the battery monitoring device 10 can determine the state of the battery using the difference between the first current value and the second current value (step S190).

[0080] FIG. 5 is a detailed flowchart of step S150 in FIG. 5, the first and second voltage drops are converted into digital values ​​(steps S151 and S161) and then converted into current values ​​(steps S152 and S162) by the voltage measurement unit 220. In this case, the first current value is amplified by an amplifier (step S153).

[0081] Next, linearity compensation is performed on the first and second current values. The linearity compensation process may include determining an amplification factor (256x, 64x, 16x, 4x) depending on the magnitude of the current value (step S154) and determining a current range as shown in FIG. 6 (steps S155 and S165). The temperature converted in step S158 is used for linearity compensation (steps S156a and S165a), and linear data is used (steps S156a and S165a). Through linearity compensation, the first and second current values ​​are compensated to new first and second current values.

[0082] The first and second temperature values ​​collected through the internal sensor, i.e., the first temperature sensor 310, and the external sensor, i.e., the second temperature sensor 320, are converted into digital values ​​(step S157), and the temperatures are converted by applying weights (step S158).

[0083] FIG. 6 is a diagram illustrating an example of linearity compensation according to an embodiment of the present invention. Referring to Figure 6, a graph is shown showing the results before and after compensation using the linearity-related calibration and compensation algorithm. The current value error is depicted as a discontinuous graph according to the size interval. For example, the current value error is depicted in four intervals. Through linearity compensation, the graph is rearranged around 0% error, which is the center of the positive and negative errors (yellow line), and finally, through linearity compensation, the error range is compensated to approach 0% (green line). Here, "Linearity compensation" refers to the point where linearity compensation is performed, and "customer spec" refers to the required error range.

[0084] FIG. 7 is a detailed flowchart of step S170 in FIG.

[0085] FIG. 8 is a detailed flowchart of step S180 in FIG.

[0086] 7 illustrates a temperature compensation process for a first current value, and FIG. 8 illustrates a temperature compensation process for a second current value. Since the temperature compensation process is common to both the first and second currents, FIG. 7 will be used as a representative example.

[0087] In S171, it is checked whether the measured current value is within the current range that the temperature sensor can respond to. Looking at the data before correction in Figure 10, a deviation between the temperature sensor and the actual temperature occurs at currents above about 300A.

[0088] In S172, the current application time is checked because even if a constant current is applied, the amount of error changes over time, which results in a change in the predicted temperature value over time.

[0089] In step S172, since the predicted temperature is a function of the current and time, a correction limit value is set and a process for checking this portion is carried out. The predicted temperature is changed in real time according to the current and time.

[0090] In S174, if the applied current value is equal to or less than the predicted temperature value, this is a routine for returning the predicted temperature to zero.

[0091] In S175a, the speed at which the predicted temperature control value based on the current value and application time is restored is adjusted (the time until the temperature sensor value and the actual temperature become the same is adjusted).

[0092] Since the accuracy varies depending on the current value and time, the temperature prediction control value must estimate the gradient of the error value.

[0093] FIG. 9 is a diagram illustrating an example of temperature compensation according to one embodiment of the present invention. 9 illustrates the temperature compensated for by predictive control. The time it takes for the temperature sensor to reflect the actual temperature can vary depending on the current value. Therefore, when changing from a high current to a low current, an algorithm is used to estimate the temperature predictive control value as the actual temperature.

[0094] FIG. 10 is a diagram illustrating an example before temperature compensation according to an embodiment of the present invention.

[0095] FIG. 11 is a diagram showing an example after temperature compensation according to one embodiment of the present invention.

[0096] 10, which shows an example before temperature compensation, the error in the current value increases over time, and in some cases the error in the current value exceeds the error range of 0.05%.

[0097] On the other hand, referring to FIG. 11, in the diagram showing an example after temperature compensation, it can be seen that the error in the current value converges to a certain error range, for example, within the range of −0.10 to 0.10%.

[0098] FIG. 12 is a detailed flowchart of step S190 in FIG. 12, the current value is updated based on the voltage value measured in real time (step S191), the difference between the first and second current values ​​is calculated (step S192), and the difference between the current values ​​is compared (step S193). The difference between the current values ​​is checked to see if it is within a critical value range (step S194), and if it is outside the critical value range, counting continues (step S195). If the difference between the current values ​​is outside the critical value range, it is determined whether the count number is outside the reference value (step S196), and if the count number is outside the reference value, a warning message is output (step S197). If the difference between the current values ​​is within the critical value, the system is operating normally (step S198).

[0099] FIG. 13 is a diagram showing an example of a comparison between before and after compensation according to an embodiment of the present invention. Referring to FIG. 13, the accuracy of the current value before compensation and the accuracy of the current value after compensation through linearity compensation and temperature compensation are illustrated.

[0100] FIG. 14 is a diagram illustrating an example of accuracy and linearity with compensation according to an embodiment of the present invention. 14, through the linearity compensation algorithm, the error of 0.08% before compensation was reduced to 0.02%, and the current accuracy of the first and second current values ​​was improved from -0.03 to 0.05% before compensation to -0.01 to 0.01%.

[0101] As described above, according to one embodiment of the present invention, the measurement error of the current value is reduced through linearity compensation and temperature compensation.

[0102] In addition, the reliability of monitoring information regarding the battery state can be improved by using a current value that has undergone linearity compensation and temperature compensation.

[0103] The above describes various preferred embodiments of the present invention using some examples. However, the descriptions of the various embodiments described in the "Specific Contents for Carrying Out the Invention" section are merely illustrative, and a person skilled in the art will understand from the above description that the present invention can be implemented in various modified forms or in an equivalent manner to the present invention.

[0104] Furthermore, since the present invention can be embodied in various other forms, the present invention is not limited to the above description. The above description is provided so that the disclosure of the present invention will be complete and will fully convey the scope of the present invention to those skilled in the art. It should be understood that the present invention is defined only by the claims. [Explanation of symbols]

[0105] 10: Battery monitoring device 100: Busbar 200: Measuring part 210: Control unit 220: Voltage measurement unit 230: Current calculation unit 240:Temperature measurement part 250: Current compensation section 260: Linearity compensation section 270: Temperature compensation section 280: Battery state determination unit 310: First temperature sensor 320: Second temperature sensor

Claims

1. 1. A method performed by a battery monitoring device, comprising: measuring a first voltage drop across a first shunt resistor in a bus bar electrically coupled to the battery and a second voltage drop across a second shunt resistor in parallel or series with the first shunt resistor; calculating a first current and a second current flowing through the first shunt resistor and the second shunt resistor, respectively, using a first voltage drop value and a second voltage drop value; increasing an error count when a difference between the first current value and the second current value exceeds a predetermined critical value, and determining that the battery is in an abnormal state when the error count exceeds a predetermined critical number of times; determining that the battery is in a normal state if the difference between the first current value and the second current value is equal to or less than the predetermined critical value; configured to include The method further includes measuring a temperature according to the current using a temperature sensor, and performing linearity compensation on the first current value and the second current value using linear data including a measured temperature value, inflection point information between the first current value and the second current value, an amplification value of the first current value and the second current value, and a predicted temperature increase value due to the current. and / or The method further includes performing synchronization and temperature compensation on the first current value and the second current value, which change rapidly according to a change in the measured temperature value; The step of performing synchronization and temperature compensation includes: determining a temperature prediction variable according to the magnitudes of the first current value and the second current value and a current application time; calculating a temperature predictor value based on the temperature predictor; performing temperature compensation on the first current value and the second current value using the temperature prediction variable value; A battery monitoring method comprising:

2. The step of calculating the first current and the second current includes: converting the first voltage drop value and the second voltage drop value into digital values; calculating the first current value and the second current value by applying calibration data of the first shunt resistor and calibration data of the second shunt resistor to the first voltage drop value and the second voltage drop value; amplifying the first current value and the second current value; The battery monitoring method of claim 1 , further comprising:

3. The temperature sensor an internal temperature sensor for measuring a first temperature value of the bus bar and an external temperature sensor for measuring a second temperature value of a PCB on which the bus bar is provided; The battery monitoring method of claim 1 , wherein measuring the temperature comprises applying a weight to each of the first temperature value and the second temperature value.

4. The step of performing linearity compensation includes: The battery monitoring method of claim 1, wherein linearity is compensated for for each current section due to an inflection point according to an amplification factor of the first current and the second current.

5. a voltage measuring unit that measures a first voltage drop across a first shunt resistor of a bus bar electrically connected to a battery and a second voltage drop across a second shunt resistor that is in a parallel or series relationship with the first shunt resistor; a current calculation unit that calculates a first current and a second current flowing through the first shunt resistor and the second shunt resistor, respectively, using a first voltage drop value and a second voltage drop value; a temperature measurement unit that measures a temperature change caused by the first current and the second current using a temperature sensor; a control unit that increases an error count when a difference between the first current value and the second current value calculated through linearity compensation according to device characteristics, synchronization, and temperature compensation exceeds a predetermined critical value, determines that the battery is in an abnormal state when the error count exceeds a predetermined critical number, and determines that the battery is in a normal state when the difference between the first current value and the second current value is equal to or less than the predetermined critical value; configured to include The power supply may further include a linearity compensator that compensates for linearity for each current section based on an inflection point according to an amplification factor of the first current and the second current. and / or a temperature compensation unit that determines a temperature prediction variable based on magnitudes of the first current value and the second current value and a current application time, and performs temperature compensation on the first current value and the second current value using a temperature prediction variable value calculated based on the temperature prediction variable.

6. The battery monitoring device according to claim 5 , further comprising a battery state determination unit that determines an error based on the range of the difference value and diagnoses the state of the battery based on the number of occurrences of the error.

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