Battery status determination method and status determination system

Abstract

To provide a battery state determination method and a state determination system capable of improving the accuracy of determining the battery state without increasing the burden of measuring a battery.SOLUTION: A method for determining the state of a battery 60 includes obtaining a measurement value of the magnetic field of the battery 60 mounted in a device 80 measured by a magnetic measurement unit 20, calculating information regarding the relative position of the magnetic measurement unit 20 on the basis of the measurement value of the magnetic field of the battery 60 and a reference value of the magnetic field of the battery 60, and determining the state of the battery 60 on the basis of the information regarding the relative position of the magnetic measurement unit 20.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for determining the state of a battery and a state determination system.

Background Art

[0002] Conventionally, an apparatus for inspecting a battery by comparing the current distribution of the battery to be inspected with a normal current distribution is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The current distribution of the battery to be compared with the normal current distribution is measured with the position of the current measuring device aligned with the reference position of the battery. The measurement accuracy of the current distribution of the battery is affected by the positional deviation of the measuring device with respect to the reference position of the battery. When determining the state of the battery based on the measurement result of the current distribution of the battery, it is required to improve the determination accuracy without increasing the measurement burden.

[0005] The present disclosure has been made in view of the above points, and an object thereof is to provide a method for determining the state of a battery and a state determination system that can improve the determination accuracy of the state of the battery without increasing the measurement burden of the battery.

Means for Solving the Problems

[0006] (1) A battery state determination method according to several embodiments includes obtaining a measurement value of the magnetic field of a battery mounted in a device measured by a magnetic measuring unit, calculating information regarding the relative position of the magnetic measuring unit based on the measurement value of the battery's magnetic field and a reference value of the battery's magnetic field, and determining the state of the battery based on the information regarding the relative position of the magnetic measuring unit. In this way, a positional misalignment between the battery and the magnetic measuring unit is permitted. As a result, the accuracy of determining the state of the battery can be improved even when the battery is measured without being removed from the device.

[0007] (2) The battery status determination method described in (1) above may include determining that the battery is abnormal when the information regarding the relative position of the magnetic measuring unit satisfies the abnormality determination conditions. In this way, the battery is determined to be abnormal without correcting the measured values. In other words, unnecessary correction operations are omitted. As a result, the operating load of the control device is reduced.

[0008] (3) The battery state determination method described in (1) or (2) above may include calculating a correction coefficient for the relative position of the magnetic measuring unit as information regarding the relative position of the magnetic measuring unit. In this way, a positional misalignment between the battery and the magnetic measuring unit is permitted.

[0009] (4) The battery state determination method described in any one of (1) to (3) above may include moving the magnetic measuring unit along one scanning direction in order to measure the magnetic field of the battery with the magnetic measuring unit. In this way, the control device can measure the distribution of the magnetic field generated by the battery.

[0010] (5) The battery state determination method described in (4) above may include shifting the magnetic measuring unit to each of a plurality of positions that are periodically or aperiodically arranged in a direction intersecting the scanning direction, and moving it along the scanning direction from each position. In this way, the control device can measure the planar distribution of the magnetic field generated by the battery.

[0011] (6) The battery state determination method described in (5) above may include shifting the magnetic measuring unit to each position where movement in the scanning direction began when measuring the reference value of the battery's magnetic field, and then moving it along the scanning direction from each position. In this way, the control device can compare the reference value and the measured value with high accuracy.

[0012] (7) The battery state determination method described in any one of (4) to (6) above may include moving the magnetic measuring unit in each of a plurality of directions, including at least a first direction and a second direction, to obtain a measurement of the magnetic field of the battery, and determining the scanning direction based on a first measurement obtained by moving the magnetic measuring unit in the first direction and a second measurement obtained by moving the magnetic measuring unit in the second direction. In this way, the magnetic measuring unit is scanned so that the position of the battery approaches the reference position. As a result, the positional or orientation deviation of the battery is reduced.

[0013] (8) The battery status determination method described in any one of (4) to (7) above may include moving the magnetic measuring unit within a scanning range determined based on the type of device in which the battery is installed. This reduces unnecessary scanning, thereby increasing measurement efficiency.

[0014] (9) A battery state determination system according to some embodiments comprises a magnetic measuring unit and a control device as described in any one of (1) to (8) above.

[0015] (10) The battery state determination system described in (9) above may further include a moving device for moving the magnetic measuring unit relative to the battery. The moving device may be configured to move between the surface on which the equipment on which the battery is mounted is installed and the battery.

[0016] (11) The battery state determination system according to the above (9) or (10) may further include a driving device that moves the device on which the battery is mounted with respect to the magnetic measurement unit. By doing so, the measurement accuracy of the magnetic field of the battery or the determination accuracy of the state of the battery is improved.

[0017] (12) In the battery state determination system according to any one of the above (9) to (11), the magnetic measurement unit may include one or more magnetic sensors that measure the magnetic field of the battery.

[0018] (13) In the battery state determination system according to the above (12), the magnetic measurement unit may include a plurality of the magnetic sensors arranged in a linear or array shape. By doing so, the number of scanning times of the magnetic measurement unit is reduced.

[0019] (14) In the battery state determination system according to the above (12) or (13), the magnetic measurement unit may include a plurality of the magnetic sensors arranged in a range covering the entire battery. By doing so, the scanning of the magnetic measurement unit is omitted.

[0020] (15) In the battery state determination system according to the above (14), the control device may select some of the plurality of magnetic sensors and acquire the measurement values of the selected magnetic sensors. By doing so, the magnetic measurement unit is pseudo-scanned.

Effect of the Invention

[0021] According to the battery state determination method and state determination system according to the present disclosure, the influence of the position of the measurement device is reduced.

Brief Description of the Drawings

[0022] [Figure 1] It is a side view showing an example of the positional relationship between the battery and the magnetic measurement unit. [Figure 2] It is a plan view showing an example of the positional relationship between the battery and the magnetic measurement unit. [Figure 3]It is a block diagram showing a configuration example of a state determination system according to an embodiment. [Figure 4] It is a flowchart showing an example of a procedure of a method for determining the state of a battery. [Figure 5] It is a diagram showing an example in which a battery is arranged such that the array of cells of the battery is along the scanning direction of the magnetic measurement unit. [Figure 6] It is a diagram showing an example in which a battery is arranged such that the array of cells of the battery is inclined with respect to the scanning direction of the magnetic measurement unit. [Figure 7] It is a diagram showing an example in which a battery is arranged such that the array plane of cells of the battery is parallel to the scanning plane of the magnetic measurement unit. [Figure 8] It is a diagram showing an example in which a battery is arranged such that the array plane of cells of the battery is inclined with respect to the scanning plane of the magnetic measurement unit. [Figure 9] It is a diagram showing an example in which a battery is arranged such that the distance between the array of cells of the battery and the scanning path of the magnetic measurement unit changes. [Figure 10] It is a graph showing an example of a waveform of a magnetic field measurement value measured by the magnetic measurement unit when the position of the battery is shifted in the scanning direction of the magnetic measurement unit. [Figure 11] It is a graph showing an example of a waveform of a magnetic field measurement value measured by the magnetic measurement unit when the position of the battery is shifted so that the distance between the array of cells of the battery and the scanning path of the magnetic measurement unit increases. [Figure 12] It is a graph showing an example of a waveform of a magnetic field measurement value measured by the magnetic measurement unit when the position of the battery is shifted so that the array plane of cells of the battery rotates about an axis intersecting the scanning direction of the magnetic measurement unit. [Figure 13] It is a three-dimensional graph showing an example of waveforms of magnetic field measurement values of each scanning path measured by scanning the magnetic measurement unit along a plurality of scanning paths. [Figure 14] It is a diagram showing an example of scanning the magnetic measurement unit in two intersecting directions for a preliminary diagnosis of the array of cells of the battery. [Figure 15] It is a side view showing an example of a moving device that moves the magnetic measurement unit in the scanning direction. [Figure 16]This is a plan view showing an example of a drive system for moving a vehicle equipped with batteries. [Modes for carrying out the invention]

[0023] A magnetic field is generated when charging and discharging current flows through a secondary battery. The state of a secondary battery can sometimes be inspected by measuring the magnetic field generated during charging and discharging. A battery to be measured for magnetic field analysis is, for example, a battery having an electrode body in which a positive electrode active material layer and a negative electrode active material layer are stacked with an insulating layer in between, and an outer casing that houses the electrode body. Hereinafter, embodiments of the battery state determination method and state determination system 1 (see Figure 3) according to this disclosure will be described in comparison with comparative examples.

[0024] (Comparative example) The apparatus in the comparative example first obtains data on the current distribution of a normal battery by placing a normal battery in a reference position and measuring the magnetic field when a reference current is passed through the normal battery using a magnetic measuring unit. The apparatus in the comparative example first obtains data on the current distribution of a battery to be tested by placing the battery to be tested in a reference position and measuring the magnetic field when a reference current is passed through the battery to be tested using a magnetic measuring unit. The apparatus in the comparative example determines the state of the battery to be tested by comparing the current distribution data of the battery to be tested with the current distribution data of a normal battery.

[0025] Here, if the battery being tested is misaligned from its reference position, an error occurs in the current distribution data of the battery being tested. This error in the current distribution data reduces the accuracy of the battery condition test. In other words, misalignment of the battery being tested affects the accuracy of the battery condition test.

[0026] However, the apparatus in the comparative example may not be able to accurately position the battery under inspection at a reference location. For example, if the battery under inspection is mounted on an electric vehicle, it is difficult to accurately reproduce the vehicle's position and orientation. If the battery under inspection needs to be removed from the vehicle in order to accurately reproduce its position and orientation, the work of removing the battery from the vehicle increases the workload and cost of battery inspection. Therefore, it is necessary to determine the state of the battery while taking into account the effect of any displacement in the battery's position.

[0027] Therefore, the battery state determination method and state determination system 1 (see Figure 3) according to this disclosure determines the state of the battery by measuring the magnetic field of the battery without attaching or detaching the battery from equipment such as an electric vehicle, taking into account the displacement of the battery being inspected. The battery state determination method and state determination system 1 according to one embodiment of this disclosure will be described below.

[0028] (One embodiment of the present disclosure) As shown in Figures 1 and 2, the battery 60 to be inspected in the state determination system 1 according to one embodiment of the present disclosure is mounted on a vehicle 80. The vehicle 80 has tires 82 and is in contact with the ground 70 at the tires 82. In this embodiment, the ground 70 is assumed to be aligned with the XY plane. The normal direction (vertical direction) of the ground 70 corresponds to the Z axis. The vertically upward direction is assumed to be the positive direction of the Z axis.

[0029] The battery 60 has cells 62 (see Figure 5) arranged in a grid, as will be described later. The battery 60 is mounted on the vehicle 80 such that the plane on which the cells 62 are arranged is aligned with the ground 70. The magnetic measuring unit 20 is installed on the ground 70 and measures the magnetic field generated by the battery 60. The magnetic measuring unit 20 may be configured to move along the ground 70, that is, along the direction of the arrangement of the cells of the battery 60. The vehicle 80 may be configured to move along the ground 70, that is, along the direction of the arrangement of the cells of the battery 60, relative to the magnetic measuring unit 20.

[0030] (Example configuration of state determination system 1) As shown in Figure 3, a state determination system 1 according to one embodiment of the present disclosure comprises a control device 10 and a magnetic measuring unit 20. The control device 10 comprises an acquisition unit 11, a calculation unit 12, a determination unit 13, and a scanning unit 14. The acquisition unit 11 acquires the measurement results of the magnetic field of the battery 60 from the magnetic measuring unit 20. By scanning the magnetic measuring unit 20 with respect to the battery 60, the acquisition unit 11 can acquire the distribution of the measurement results of the magnetic field of the battery 60. The calculation unit 12 calculates the current distribution of the battery 60 based on the measurement results of the magnetic field of the battery 60. The determination unit 13 determines the state of the battery 60 based on the current distribution of the battery 60. The scanning unit 14 controls the position of the magnetic measuring unit 20 so that the magnetic measuring unit 20 scans the battery 60 when the magnetic measuring unit 20 is configured to be movable. The scanning unit 14 measures the magnetic field of the battery 60 by scanning the magnetic measuring unit 20 by moving it along one scanning direction.

[0031] The acquisition unit 11 includes a communication device for communicating with the magnetic measurement unit 20 via wired or wireless connection. The communication device may include a communication module that transmits and receives data based on data communication standards such as RS-232C or RS-485. The communication device may include a communication module that supports mobile communication standards such as 4G (4th Generation), LTE (Long Term Evolution), or 5G (5th Generation). The communication device is not limited to the example communication module and may include various other devices or modules.

[0032] The calculation unit 12, the determination unit 13, or the scanning unit 14 may include a processor such as a CPU (Central Processing Unit). The calculation unit 12, the determination unit 13, or the scanning unit 14 may realize predetermined functions by causing the processor to execute predetermined programs. The calculation unit 12, the determination unit 13, or the scanning unit 14 may be configured as an integrated unit with at least some combinations, or they may be configured as separate units. Hereinafter, the calculation unit 12, the determination unit 13, or the scanning unit 14 will also be collectively referred to as the control unit. The control unit may include a storage unit. The storage unit may store various information used in the operation of the control unit, or programs for realizing the functions of the control unit. The storage unit may function as the work memory of the control unit. The storage unit may be composed of, for example, semiconductor memory. The storage unit may include volatile memory or non-volatile memory. The storage unit may be included in the control unit, or it may be configured as a separate unit from the control unit.

[0033] The magnetic measuring unit 20 may be equipped with a magnetic sensor for measuring magnetic fields. The magnetic measuring unit 20 may have one or more magnetic sensors. The magnetic measuring unit 20 may be configured by arranging multiple magnetic sensors in a linear or array configuration. As described above, when the magnetic measuring unit 20 scans the battery 60, the number of scans is reduced by arranging the magnetic sensors in a linear or array configuration. The reduction in the number of scans shortens the measurement time for the magnetic field of the battery 60.

[0034] The magnetic measuring unit 20 may be configured by arranging multiple magnetic sensors to cover the entire battery 60. By arranging multiple magnetic sensors to cover the entire battery 60, scanning of the battery 60 by the magnetic measuring unit 20 is omitted. The magnetic measuring unit 20 may select a specific magnetic sensor from among the multiple magnetic sensors arranged to cover the entire battery 60 and obtain a measurement value for the selected specific magnetic sensor. In other words, the magnetic measuring unit 20 may select some of the magnetic sensors from among the multiple magnetic sensors arranged to cover the entire battery 60 and obtain a measurement value for the selected some magnetic sensors. By obtaining a measurement value for some magnetic sensors, the operation of scanning the magnetic sensors is simulated. The specific magnetic sensor may be selected from magnetic sensors arranged at equal intervals, or from magnetic sensors arranged at arbitrary intervals that are not equal.

[0035] The magnetic sensor may be configured to measure the magnetic field in one axis, or it may be configured to measure the magnetic field in three axes simultaneously. Regardless of the direction of the measurement axis of the magnetic sensor, it is desirable that the magnetic sensor be positioned so that the magnetic sensing surface and the magnetic field emitted by the battery 60 are perpendicular to each other. The reason for positioning the magnetic sensor so that the magnetic sensing surface and the magnetic field emitted by the battery 60 are perpendicular to each other is that by aligning the macroscopic current of the battery 60 with the magnetic sensing surface, it becomes easier to obtain a magnetic field distribution that reflects the orientation or position of the battery 60.

[0036] A magnetic sensor may include at least one magnetic element. The magnetic element may be an analog or digital element. The magnetic element may include, for example, a magnetoresistive element such as a Hall element, AMR (Anisotropic magnetoresistance effect), GMR (Giant magnetoresistance effect), or TMR (Tunnel magnetoresistance effect). The magnetic element may include, for example, a magneto-impedance element such as MI (Magneto-Impedance) or a fluxgate. The magnetic element may include, for example, a thin-film magnetic element based on the anomalous Hall effect using a topological magnetic material. If an alternating current is flowing through the object to be measured, a pickup coil may be used as the magnetic element.

[0037] The magnetic measuring unit 20 is not limited to a magnetic sensor and may include various other configurations capable of measuring magnetic fields.

[0038] (Example of operation of state determination system 1) A state determination system 1 according to one embodiment of this disclosure determines the state of a battery 60 by measuring the magnetic field of the battery 60. The control device 10 may execute a battery state determination method including the steps of the flowchart illustrated in Figure 4. The battery state determination method may be implemented as a state determination program to be executed by a processor constituting the control device 10. The state determination program may be stored in a non-temporary computer-readable medium.

[0039] The control device 10 acquires a reference value for the magnetic field of the battery 60 (step S1). The reference value is the measured value of the magnetic field obtained by scanning the magnetic measuring unit 20 with the battery 60 placed in a reference position, provided that the battery 60 is known to be in a normal state.

[0040] The battery 60 has cells 62 arranged in a grid along the X-axis and Y-axis directions, respectively, as illustrated in Figure 5. In other words, the cells 62 are arranged on an arrangement plane along the XY plane. In this embodiment, the magnetic measuring unit 20 is scanned in the X-axis direction. That is, the scanning direction 22 of the magnetic measuring unit 20 corresponds to the X-axis direction. The magnetic measuring unit 20 is scanned multiple times, with the starting point of the scan shifted in the Y-axis direction. In other words, the control device 10 may scan the magnetic measuring unit 20 by moving it along the scanning direction 22 from each of a plurality of positions shifted to each of a plurality of positions arranged periodically or aperiodically in a direction intersecting the scanning direction 22. The reference position of the battery 60 is the installation position of the battery 60 when the arrangement direction of the cells 62 coincides with the scanning direction 22 of the magnetic measuring unit, as shown in Figure 5.

[0041] As illustrated in Figure 6, the battery 60 may be positioned such that the arrangement direction of the cells 62 is tilted with respect to the X-axis and Y-axis directions. In other words, the scanning direction 22 of the magnetic measuring unit 20 is tilted with respect to the arrangement direction of the cells 62. In this case, the installation position of the battery 60 is shifted from the reference position. Therefore, the position and orientation of the battery 60 or the equipment on which the battery 60 is mounted, or the scanning direction of the magnetic measuring unit 20, is adjusted so that the position of the battery 60 becomes the reference position.

[0042] As illustrated in Figure 7, the battery 60 is installed in the vehicle 80 such that the cells 62 are aligned along the XY plane. The magnetic measuring unit 20 is scanned in the depth direction of the paper. The reference position of the battery 60 is the installation position of the battery 60 when the distance in the Z-axis direction between the magnetic measuring unit 20 and the arrangement plane of the cells 62 is constant when the magnetic measuring unit 20 is scanned.

[0043] As illustrated in Figures 8 and 9, if the vehicle 80 carrying the battery 60 is tilted relative to the ground 70, the battery 60 may be positioned such that the arrangement plane of the cells 62 is tilted with respect to the XY plane. In the example in Figure 8, the arrangement plane of the cells 62 is rotated around the X axis. In other words, the arrangement plane of the cells 62 is parallel to the X axis and tilted with respect to the Y axis. In the example in Figure 9, the arrangement plane of the cells 62 is rotated around the Y axis. In other words, the arrangement plane of the cells 62 is parallel to the Y axis and tilted with respect to the X axis. In these cases, the installation position of the battery 60 is deviated from the reference position. Therefore, the position and orientation of the battery 60 or the equipment carrying the battery 60, or the scanning direction of the magnetic measuring unit 20, is adjusted so that the position of the battery 60 becomes the reference position.

[0044] The reference value may be a measured magnetic field value with the battery 60 installed in the device, or it may be a measured magnetic field value with the battery 60 removed from the device. The reference value may be represented as a waveform of continuous magnetic field measurements along the scanning direction of the magnetic measuring unit 20 (see, for example, the graph in Figure 10). The reference value may also be represented as a set of magnetic field measurements at discrete positions along the scanning direction of the magnetic measuring unit 20. In this embodiment, the reference value is represented as a continuous waveform. The waveform representing the reference value changes with a period corresponding to the interval of the cells 62. The waveform representing the reference value may be, for example, a sine wave or a waveform approximated by a sine wave. The waveform representing the reference value is not limited to a sine wave, but may be any other waveform with periodicity, such as a triangular wave or a pulse wave.

[0045] The waveform representing the reference value is not limited to waveforms with a constant amplitude, such as sine waves, but may also include waveforms with varying amplitudes. In the arrangement of the electrodes of battery 60, if one positive electrode and one negative electrode are alternately arranged in a certain direction, the amplitude of the waveform representing the reference value may be constant. On the other hand, in the arrangement of the electrodes of battery 60, if the positive and negative electrodes are not alternately arranged in a certain direction, there may be a bias in the number of positive or negative electrodes in a limited section. For example, if the electrodes of battery 60 are arranged in the order of positive electrode, positive electrode, negative electrode, negative electrode, positive electrode, the waveform measured by taking only the section in which the first two positive electrodes are arranged will have a different amplitude than the waveform measured including the other sections. In other words, the amplitude of the waveform is not constant depending on the section being measured. Therefore, the waveform representing the reference value is not limited to sine waves or waveforms approximated by sine waves, but may also be a waveform approximated by a polynomial of order two or higher. In other words, the waveform representing the reference value may be a waveform that does not have periodicity in at least some sections.

[0046] The control device 10 may acquire pre-prepared reference values ​​using the acquisition unit 11. Reference values ​​for the magnetic field of the battery 60 may be prepared in advance as an external database. Reference values ​​for the magnetic field of the battery 60 may be stored in a database for each type of battery 60. Reference values ​​for the magnetic field of the battery 60 may be stored in a database for each device in which the battery 60 is installed. The control device 10 may acquire the reference values ​​by scanning the magnetic measurement unit 20 with the scanning unit 14 while the battery 60, which is known to be in a normal state, is placed in a reference position, and acquiring the magnetic field measurement results from the magnetic measurement unit 20 with the acquisition unit 11.

[0047] Returning to the flowchart in Figure 4, the control device 10 measures the magnetic field of the battery 60 to be measured (step S2). Assume that the vehicle 80 or other device on which the battery 60 is installed is positioned so that the magnetic field of the battery 60 can be measured by the magnetic measuring unit 20. If the magnetic measuring unit 20 is configured to be movable, the control device 10 scans the magnetic measuring unit 20 with the scanning unit 14 and acquires the measurement results of the magnetic field generated from each part of the battery 60 with the acquisition unit 11. If the device on which the battery 60 is installed is configured to be movable, the control device 10 controls the position of the device so that the measurement results of the magnetic field generated from each part of the battery 60 can be acquired with the acquisition unit 11.

[0048] The control device 10 may scan the magnetic measuring unit 20 multiple times by shifting the starting point of the scan in the Y-axis direction in order to measure the magnetic field of the battery 60 to be measured. In other words, the control device 10 may scan the magnetic measuring unit 20 by moving it along the scanning direction 22 from each of a plurality of positions that are shifted to each of a plurality of positions that are periodically or aperiodically arranged in a direction intersecting the scanning direction 22. The control device 10 may shift the magnetic measuring unit 20 to each position where movement in the scanning direction began when the reference value of the magnetic field of the battery 60 was measured, and then move the magnetic measuring unit 20 along the scanning direction from each position. In other words, the control device 10 may scan the magnetic measuring unit 20 in line with the starting point of the scan when the reference value of the magnetic field of the battery 60 was measured. By aligning the starting point of the scan for measuring the magnetic field of the battery 60 to be measured with the starting point of the scan when the reference value of the magnetic field of the battery 60 was measured, the control device 10 can compare the reference value and the measured value with high accuracy.

[0049] The control device 10, in its calculation unit 12, determines whether the difference between the reference value and the measured value of the magnetic field of the battery 60 satisfies the matching conditions (step S3). The matching conditions include the reference value and the measured value of the magnetic field of the battery 60 matching, or the difference between the reference value and the measured value of the magnetic field of the battery 60 being small.

[0050] Figures 10, 11, and 12 illustrate examples of waveforms of the measured values ​​of battery 60 when its installation position is deviated from the reference position. In the graphs of Figures 10 to 12, the horizontal axis represents the X-coordinate position corresponding to the position in the X-axis direction. The vertical axis represents the measured magnetic field value at each position. Solid lines represent the reference value. Dotted lines represent the measured values.

[0051] In Figure 10, the phase of the measured waveform is shifted by ΔT in the X-axis direction relative to the phase of the reference value waveform. In this case, the installation position of the battery 60 is shifted from the reference position in the X-axis direction. The calculation unit 12 may determine that the matching condition is met if ΔT, which is the difference between the phase of the measured waveform and the phase of the reference value waveform, is less than the phase threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if ΔT, which is the difference between the phase of the measured waveform and the phase of the reference value waveform, is greater than or equal to the phase threshold. The phase threshold may be set as appropriate. As described above, the shift in the X-axis direction of the battery 60 without changing its orientation at the reference position is detected as a phase shift in the waveform.

[0052] In Figure 11, the amplitude (A') of the measured waveform is smaller than the amplitude (A) of the reference waveform. In this case, the battery 60 is separated from the magnetic measuring unit 20 without changing its orientation at the reference position. That is, the installation position of the battery 60 is shifted in the Z-axis direction from the reference position while the arrangement plane of the cells 62 remains aligned with the XY plane. The calculation unit 12 may determine that the matching condition is met if the difference between the amplitude of the measured waveform and the amplitude of the reference waveform is less than the amplitude threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if the difference between the amplitude of the measured waveform and the amplitude of the reference waveform is greater than or equal to the amplitude threshold. The amplitude threshold may be set as appropriate. As described above, the shift in the Z-axis direction of the battery 60 without changing its orientation at the reference position is detected as a change in the amplitude of the waveform.

[0053] In Figure 12, the period (T') of the measured waveform is shorter than the period (T) of the reference value waveform. Also, the amplitude (A') of the measured waveform increases as it moves in the positive direction of the X-axis. Conversely, the amplitude (A') of the measured waveform decreases as it moves in the negative direction of the X-axis. The amplitude of the waveform is represented by a dashed line connecting the peaks of the waveform. In this case, the arrangement plane of the cells 62 of the battery 60 is rotated around the Y-axis as illustrated in Figure 9. The calculation unit 12 may determine that the matching condition is met if the difference between the period of the measured waveform and the period of the reference value waveform is less than the period threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if the difference between the period of the measured waveform and the period of the reference value waveform is greater than or equal to the period threshold. The period threshold may be set as appropriate. The calculation unit 12 may also determine that the matching condition is met if the rate of change of the amplitude of the measured waveform with respect to the X coordinate is less than the amplitude change threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if the rate of change in the amplitude of the measured waveform with respect to the X coordinate is greater than or equal to the amplitude change threshold. The amplitude change threshold may be set as appropriate. As described above, the rotation of the battery 60 around the Y axis is detected as a change in the period of the waveform or as a rate of change in the amplitude with respect to the X axis coordinate.

[0054] As described above, positional deviations in the X-axis and Z-axis directions, as well as rotation around the Y-axis, are detected.

[0055] In addition, displacement in the Y-axis direction and rotation around the X and Z axes are detected. To detect these displacements and rotations, the control device 10 scans the magnetic measuring unit 20 in a planar manner by scanning it through multiple scanning paths. By scanning the magnetic measuring unit 20 through multiple scanning paths, the control device 10 can measure the planar distribution of the magnetic field generated by the battery 60. For example, when scanning the magnetic measuring unit 20 with the X-axis direction as the scanning direction, the scanning unit 14 of the control device 10 may scan the magnetic measuring unit 20 through multiple scanning paths with the scanning start point shifted in the Y-axis direction. The scanning start point is the starting point of the scanning path of the magnetic measuring unit 20, and is the position where the magnetic measuring unit 20 begins to move in the scanning direction. In other words, the scanning unit 14 may set scanning start points at each of multiple positions that are periodically or aperiodically arranged in directions intersecting the scanning direction, and move the magnetic measuring unit 20 along the scanning direction from each position.

[0056] Each position that serves as the scanning start point is set to be the same as the scanning start point when the reference value of the magnetic field of the battery 60 was measured. In other words, multiple scanning paths may be set to be the same when measuring the reference value and when measuring the battery 60 to be judged. The magnetic measuring unit 20 may be shifted to each position where movement in the scanning direction started when the reference value of the magnetic field of the battery 60 was measured, and then moved along the scanning direction from each position. In this way, the control device 10 can compare the reference value and the measured value with high accuracy.

[0057] Multiple scanning paths may be set to different paths when measuring the reference value and when measuring the battery 60 to be judged. In this case, the control device 10 may compare the reference value and the measured value by interpolating the measured values ​​between the multiple scanning paths.

[0058] Specifically, as illustrated in Figure 13, waveforms 51-55 of multiple measurements can be obtained by scanning in the X-axis direction from each of multiple starting points shifted in the Y-axis direction. The graph in Figure 13 is a three-dimensional graph representing the magnitude of magnetic field measurements at each position in the XY plane. Each waveform in the graph of Figure 13 represents the result of scanning in the X-axis direction. In the three-dimensional graph of Figure 13, an envelope is generated connecting magnetic field measurements aligned in the Y-axis direction at a specific X-coordinate. The envelope corresponds to the result of scanning in the Y-axis direction starting from that X-coordinate. The envelope can be represented as a periodic waveform when the interval between the shifted starting points in the Y-axis direction is sufficiently shorter than the period in the Y-axis direction. For example, the interval between the starting point of the scan to measure waveform 51 and the starting point of the scan to measure waveform 52 is W1 in the Y-axis direction. Also, the interval between the starting point of the scan to measure waveform 52 and the starting point of the scan to measure waveform 53 is W2 in the Y-axis direction. By further shortening W1 or W2, the envelope can be represented as a periodic waveform. W1 and W2 may be set to the same value or to different values. Also, the Y-axis spacing between waveform 53 and waveform 54, or between waveform 54 and waveform 55, may be set to the same value or to different values. The interval for shifting the scanning start point in the Y-axis direction may be set to the same value or to different values.

[0059] In other words, the interval of the scanning measurement can be periodic or random. Whether the measurement is periodic or at random intervals, a different waveform will be obtained in each measurement due to the structure of the battery 60. For example, when measuring the front of a module, the measured value is dominated by the magnetic field generated from the cell 62 or module located directly in front. However, by measuring the middle point of the module, the measured value will be influenced by the modules on both sides. From the above, the control device 10 may periodically measure the front of the module based on the structure of the device, or it may alternately measure the front and the middle. The control device 10 may measure the magnetic field wherever it can measure the magnetic field generated from the module. However, the position of measurement for the magnetic field is the same as the position specified when measuring the reference value.

[0060] The positional shift in the Y-axis direction is represented as the difference between the phase of the envelope waveform in the Y-axis direction of the 3D graph of the reference value and the phase of the envelope waveform in the Y-axis direction of the 3D graph of the measured value. The calculation unit 12 may determine that the matching condition is met if the difference between the phase of the envelope waveform in the Y-axis direction of the measured value and the phase of the envelope waveform in the Y-axis direction of the reference value is less than the phase threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if the difference between the phase of the envelope waveform in the Y-axis direction of the measured value and the phase of the envelope waveform in the Y-axis direction of the reference value is greater than or equal to the phase threshold. The phase threshold may be set to the same value for the X-axis direction and the Y-axis direction, or it may be set to different values.

[0061] The rotation around the X-axis is represented as the difference between the amplitude of the envelope waveform in the Y-axis direction of the 3D graph of the reference value and the amplitude of the envelope waveform in the Y-axis direction of the 3D graph of the measured value. The calculation unit 12 may determine that the matching condition is met if the difference between the amplitude of the envelope waveform in the Y-axis direction of the measured value and the amplitude of the envelope waveform in the Y-axis direction of the reference value is less than the amplitude threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if the difference between the amplitude of the envelope waveform in the Y-axis direction of the measured value and the amplitude of the envelope waveform in the Y-axis direction of the reference value is greater than or equal to the amplitude threshold. The amplitude threshold may be set to the same value for the X-axis direction and the Y-axis direction, or it may be set to different values.

[0062] The rotation around the Z-axis is represented as the angle that the ridge line 50, which connects the peaks of waveforms 51 to 55 in the 3D graph of the measured values, makes with respect to the Y-axis. The calculation unit 12 may determine that the matching condition is met if the angle of the ridge line 50 with respect to the Y-axis is less than the angle threshold. Conversely, the calculation unit 12 may determine that the matching condition is not met if the angle of the ridge line 50 with respect to the Y-axis is greater than or equal to the angle threshold. The angle threshold may be set as appropriate.

[0063] As described above, the matching conditions are set so that the positional deviation and orientation deviation of the battery 60 from the reference position are less than the judgment threshold.

[0064] Returning to the flowchart in Figure 4, the control device 10 proceeds to step S7 if the difference between the reference value and the measured value of the magnetic field of the battery 60 satisfies the matching condition (step S3: YES). If the difference between the reference value and the measured value of the magnetic field of the battery 60 does not satisfy the matching condition (step S3: NO), the control device 10 calculates information regarding the relative position of the magnetic measuring unit 20 in the calculation unit 12 (step S4). When the battery 60 is in a normal state and the same current flows as when measured at the reference position, the difference between the waveform of the measured value of the magnetic field of the battery 60 and the waveform of the reference value is caused by the difference in the relative position between the battery 60 or the device on which the battery 60 is installed and the magnetic measuring unit 20. In other words, the calculation unit 12 may calculate the magnitude of the positional displacement of the battery 60 in the X, Y, or Z axis direction based on the difference between the reference value and the measured value of the magnetic field of the battery 60 as information regarding the relative position of the magnetic measuring unit 20. Furthermore, the calculation unit 12 may calculate the rotation angle of the battery 60 around the X-axis, Y-axis, or Z-axis as information relating to the relative position of the magnetic measuring unit 20. The rotation angle of the battery 60 around the X-axis, Y-axis, or Z-axis represents the magnitude of the orientation deviation of the battery 60.

[0065] The calculation unit 12 may calculate a correction coefficient as information regarding the relative position of the magnetic measuring unit 20. The correction coefficient is used to correct for positional or orientation deviations of the battery 60. The correction coefficient may also be used to correct the waveform of the measured magnetic field of the battery 60 to the waveform that would be present if the battery 60 were placed in a reference position.

[0066] The calculation unit 12 may calculate a pattern representing the difference between the waveform of the reference value of the magnetic field of the battery 60 and the waveform of the measured value, as information regarding the relative position of the magnetic measurement unit 20. The calculation unit 12 may calculate a pattern representing the difference between the three-dimensional waveform of the reference value and the three-dimensional waveform of the measured value. In other words, the calculation unit 12 may recognize the difference between the waveform of the reference value and the waveform of the measured value as a pattern.

[0067] The control device 10 determines in the determination unit 13 whether the information regarding the relative position of the magnetic measuring unit 20 satisfies the abnormality determination conditions (step S5). The abnormality determination conditions are set to be met when the state of the battery 60 is not normal. For example, even if the measured value does not match the reference value or deviates significantly from the reference value, the determination unit 13 may determine that the state of the battery 60 is normal if it can identify how the battery 60 is deviating from the reference position.

[0068] Specifically, the difference between the measured magnetic field value and the reference value when the battery 60 is in a normal state is caused by the difference in the relative position of the magnetic measuring unit 20. In other words, the difference between the measured value and the reference value is caused by a misalignment or misalignment of the battery 60. In this case, the correction coefficient is calculated as a value proportional to the misalignment or misalignment of the battery 60. Then, the determination unit 13 may determine that the battery 60 is in a normal state if the magnitude of the misalignment or misalignment determined based on the correction coefficient is, for example, within the size of the device that houses the battery 60. Conversely, the determination unit 13 may determine that the battery 60 is in an abnormal state if the magnitude of the misalignment or misalignment determined based on the correction coefficient is, for example, exceeding the size of the device that houses the battery 60, or to an extent that is physically impossible. The determination unit 13 may determine that the battery 60 is in a normal state if the correction coefficient is less than the determination threshold, and that the battery 60 is in an abnormal state if the correction coefficient is equal to or greater than the determination threshold. In other words, the abnormality determination condition may be that the correction coefficient is equal to or greater than the determination threshold. The judgment threshold may be set appropriately based on, for example, the size of the device in which the battery 60 is installed.

[0069] When the determination unit 13 calculates a pattern representing the difference between the waveform of a reference value and the waveform of a measured value as information regarding the relative position of the magnetic measurement unit 20, it may determine whether the pattern corresponds to a pattern indicating that the battery 60 is in a normal state or a pattern indicating that it is in an abnormal state. The determination unit 13 may determine the state of the battery 60 by pattern matching. The determination unit 13 may also determine the state of the battery 60 using a model that outputs the state of the battery 60 when a pattern is input. In other words, the abnormality determination condition may be that the pattern representing the difference between the waveform of a reference value and the waveform of a measured value is different from the pattern indicating that the battery 60 is in a normal state.

[0070] The determination unit 13 may determine that the state of the battery 60 is abnormal, regardless of the correction coefficient, if it obtains a measurement of the magnetic field of the battery 60 that is impossible based on the structure of the device in which the battery 60 is installed. For example, if the measurement value does not match a reference value stored in a database, if a correction coefficient cannot be calculated, or if the correction coefficient falls outside a predetermined range, the determination unit 13 may determine that the state of the battery 60 is abnormal. In other words, the abnormality determination conditions may include cases where the measurement value does not match a reference value stored in a database, where a correction coefficient cannot be calculated, or where the correction coefficient falls outside a predetermined range.

[0071] If the battery 60 is not in a normal state, this may include, for example, cases where the battery 60 installed in the device is not a genuine product, the battery 60 is faulty, or the location of the battery 60 is outside the range in which the magnetic field can be measured by the magnetic measuring unit 20.

[0072] If the control device 10 determines that the information regarding the relative position of the magnetic measuring unit 20 does not meet the abnormality determination conditions (step S5: NO), the calculation unit 12 corrects the measured value of the magnetic field of the battery 60 (step S6). Specifically, the calculation unit 12 corrects the measured value of the magnetic field of the battery 60 based on the information regarding the relative position of the magnetic measuring unit 20. The calculation unit 12 may correct the measured value of the magnetic field of the battery 60 based on a correction coefficient.

[0073] If the matching condition is met in the matching condition determination procedure of step S3, or if the abnormality determination condition is not met in the abnormality determination condition determination procedure of step S5, the control device 10 executes the procedure of step S6 and then determines that the state of the battery 60 is normal (step S7). On the other hand, if the abnormality determination condition is met in the abnormality determination condition determination procedure of step S5 (step S5: YES), the control device 10 determines that the state of the battery 60 is abnormal (step S8). After executing the procedure of step S7 or S8, the control device 10 terminates the execution of the procedure in the flowchart of Figure 4.

[0074] In the flowchart of Figure 4, if the abnormality determination condition is met in step S5, the control device 10 determines that the battery 60 is abnormal without correcting the measured magnetic field value. This eliminates unnecessary correction operations, resulting in a lighter operating load on the control device 10.

[0075] (summary) As described above, according to the battery 60 state determination method of this embodiment, information regarding the relative position of the battery 60 is calculated based on the difference between the reference value and the measured value of the magnetic field of the battery 60, and the measured value is corrected. In this way, positional or orientation deviations of the battery 60 relative to the magnetic measuring unit 20 are permitted. As a result, even when it is difficult to adjust the position of the battery 60 relative to the magnetic measuring unit 20 while the battery 60 is mounted on the device, the magnetic field of the battery 60 can be measured with high accuracy without removing the battery 60 from the device. For example, the battery 60 state determination method according to this disclosure is effective when it is difficult to remove the battery 60 from the device, such as when the battery 60 is mounted on an electric vehicle. By determining the state of the battery 60 while it is mounted on the device, the accuracy of determining the state of the battery is improved without increasing the measurement burden on the battery.

[0076] (Other embodiments) The following describes a battery state determination system 1 and state determination method according to another embodiment.

[0077] <Pre-examination> The arrangement of the cells 62 of the battery 60 may be unknown. In this case, the control device 10 may pre-examine the magnetic measuring unit 20 in both the scanning direction 22X along the X axis and the scanning direction 22Y along the Y axis, as illustrated in Figure 14, and obtain measurement values ​​in each scanning direction. Based on the measurement values ​​in each scanning direction, the control device 10 may estimate the arrangement of the cells 62 of the battery 60 and determine the scanning direction of the magnetic measuring unit 20 to match the estimated arrangement. By determining the scanning direction of the magnetic measuring unit 20 based on the pre-examined measurement, the magnetic measuring unit 20 is scanned so that the position of the battery 60 approaches the reference position. As a result, the positional or orientation deviation of the battery 60 is reduced. The sensor used to pre-examine the magnetic field of the battery 60 may be the same as or different from the magnetic measuring unit 20 used to obtain the magnetic field measurement value for determining the state of the battery 60.

[0078] In other words, the control device 10 may move the magnetic measuring unit 20 in each of a plurality of directions, including at least a first direction and a second direction, to obtain a measurement of the magnetic field of the battery 60. Here, the first direction may correspond to the X-axis direction. The second direction may correspond to the Y-axis direction. The control device 10 may estimate the arrangement of the cells 62 based on a first measurement obtained by moving the magnetic measuring unit 20 in the first direction and a second measurement obtained by moving the magnetic measuring unit 20 in the second direction, and determine the scanning direction of the magnetic measuring unit 20.

[0079] When the battery 60 is installed in a vehicle, the position of the battery 60 and the arrangement of the cells 62 are determined for each vehicle model. The control device 10 may identify the vehicle model based on an image of the vehicle in which the battery 60 is installed, and determine the scanning direction and scanning range of the magnetic measuring unit 20 based on the position of the battery 60 and the arrangement of the cells 62. In other words, the control device 10 may move the magnetic measuring unit 20 within a scanning range determined based on the type of device in which the battery 60 is installed. This reduces unnecessary scanning, resulting in increased measurement efficiency.

[0080] <Position adjustment> In the embodiments described above, if the position of the battery 60 is deviated from the reference position, the control device 10 responds by correcting the measured value without adjusting the position of the battery 60 or the magnetic measuring unit 20. In another embodiment, the position of the battery 60 or the magnetic measuring unit 20 may be adjusted.

[0081] As illustrated in Figure 15, the state determination system 1 may further include a mobile device 30. The magnetic measuring unit 20 may be mounted on the mobile device 30. The mobile device 30 is configured to move, for example, along the ground 70. The mobile device 30 may also be configured to move vertically. The control device 10 may move the magnetic measuring unit 20 so that its scanning range is the same as that of the magnetic measuring unit 20 when the battery 60 is positioned at a reference location, by controlling the scanning direction of the magnetic measuring unit 20 in accordance with the displacement or orientation of the battery 60 using the scanning unit 14.

[0082] As illustrated in Figure 16, the state determination system 1 may further include a drive device 40. The drive device 40 is configured to drive a device equipped with a battery 60, such as a vehicle 80, relative to the ground 70. In the example in Figure 16, the drive device 40 moves the tires 82 of the vehicle 80 along the ground 70, thereby driving the orientation of the battery 60 from a state in which the arrangement of cells 62 is tilted with respect to the X and Y axes to a state aligned with the X and Y axes. The drive device 40 adjusts the position and orientation of the battery 60 relative to the magnetic measuring unit 20.

[0083] The control device 10 may, after adjusting the positions of the battery 60 and the magnetic measuring unit 20 as described above, repeat the measurement of the magnetic field of the battery 60 by scanning with the magnetic measuring unit 20. In other words, the control device 10 may physically correct the relative position of the magnetic measuring unit 20 and then repeat the measurement of the magnetic field. Doing so improves the accuracy of the magnetic field measurement or the accuracy of determining the state of the battery 60.

[0084] If the device equipped with the battery 60 is a low-floor vehicle 80, the magnetic measuring unit 20 may be installed to scan the bottom surface of the vehicle 80 in a space cut out of the ground 70, which is lower than the contact surface of the tire 82.

[0085] The control device 10 may use a distance measuring sensor to calculate the relative position between the battery 60 and the magnetic measuring unit 20.

[0086] While embodiments relating to this disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications or alterations are within the scope of this disclosure. For example, the functions included in each component or step can be rearranged in a logically consistent manner, and multiple components or steps can be combined into one or divided. [Explanation of Symbols]

[0087] 1. State determination system 10 Control device (11: acquisition unit, 12: calculation unit, 13: determination unit, 14: scanning unit) 20 Magnetic measurement section (22, 22X, 22Y: scanning direction) 30 Moving device (32: Direction of movement of the magnetic measuring unit) 40 Drive system (42: Direction of vehicle drive) 50 Ridge 51-55 Waveform of magnetic field measurement 60 batteries (62 cells) 70 ground 80 Vehicles (82: Tires)

Claims

1. This involves obtaining a measurement value of the magnetic field of the battery installed in the device, measured by the magnetic measurement unit, and To calculate information regarding the relative position of the magnetic measuring unit based on the measured value of the magnetic field of the battery and the reference value of the magnetic field of the battery, The state of the battery is determined based on information regarding the relative position of the magnetic measuring unit. A method for determining the state of a battery, including the following.

2. A method for determining the state of a battery according to claim 1, comprising determining that the battery is abnormal when the information regarding the relative position of the magnetic measuring unit satisfies the abnormality determination conditions.

3. The battery state determination method according to claim 2, further comprising calculating a correction coefficient for the relative position of the magnetic measuring unit as information relating to the relative position of the magnetic measuring unit.

4. A method for determining the state of a battery according to any one of claims 1 to 3, comprising moving the magnetic measuring unit along one scanning direction in order to measure the magnetic field of the battery with the magnetic measuring unit.

5. The battery state determination method according to claim 4, further comprising shifting the magnetic measuring unit to each of a plurality of positions that are periodically or aperiodically arranged in a direction intersecting the scanning direction, and moving it from each position along the scanning direction.

6. The battery state determination method according to claim 5, further comprising shifting the magnetic measuring unit to each position where movement in the scanning direction began when measuring a reference value of the battery's magnetic field, and then moving it along the scanning direction from each position.

7. The magnetic measuring unit is moved in each of a plurality of directions, including at least a first direction and a second direction, to obtain a measurement value of the magnetic field of the battery. The scanning direction is determined based on a first measurement value obtained by moving the magnetic measuring unit in the first direction and a second measurement value obtained by moving the magnetic measuring unit in the second direction. The battery state determination method according to claim 4, including the method described in claim 4.

8. The battery state determination method according to claim 4, further comprising moving the magnetic measuring unit within a scanning range determined based on the type of device in which the battery is installed.

9. A battery state determination system comprising a magnetic measuring unit and a control device that performs the battery state determination method described in any one of claims 1 to 3.

10. The device further comprises a moving device for moving the magnetic measuring unit relative to the battery, The battery state determination system according to claim 9, wherein the moving device is configured to move between the surface on which the device equipped with the battery is installed and the battery.

11. The battery state determination system according to claim 9, further comprising a drive device for moving the device on which the battery is mounted relative to the magnetic measuring unit.

12. The battery state determination system according to claim 9, wherein the magnetic measuring unit comprises one or more magnetic sensors for measuring the magnetic field of the battery.

13. The battery state determination system according to claim 12, wherein the magnetic measuring unit comprises a plurality of magnetic sensors arranged in a linear or array-like manner.

14. The battery state determination system according to claim 12, wherein the magnetic measuring unit comprises a plurality of magnetic sensors arranged to cover the entire battery.

15. The battery state determination system according to claim 14, wherein the control device selects some of the plurality of magnetic sensors and obtains the measured values ​​of the selected magnetic sensors.

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