JP2013032985A - Device and method for evaluating secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and highly accurately inspect performances of a secondary battery in a short time.SOLUTION: A voltage is applied between electrodes of a secondary battery BA to pass a current, and a magnetic sensor 10 is positioned facing a plurality of parts of the secondary battery BA, and magnetic fields at a plurality of facing positions are detected. A controller 70 calculates magnitudes of a plurality of currents flowing the plurality of parts of the secondary battery BA from the detected magnetic fields respectively and extracts the magnitudes of the plurality of currents in an electrolyte area located between the electrodes of the secondary battery BA out of the calculated magnitudes of the plurality of currents. The controller 70 creates a graph representing a distribution state of the extracted magnitudes of the plurality of currents and displays it on a display device 72.

Description

  The present invention relates to a secondary battery evaluation apparatus and evaluation method for evaluating the performance of a rechargeable battery (hereinafter referred to as a secondary battery).

  Conventionally, several methods have been proposed as methods for evaluating the performance of secondary batteries. For example, as shown in Patent Document 1 below, the secondary battery is charged to measure the charging current, and the charging capacity of the secondary battery is calculated by integrating the measured charging current, and the calculated charging There is a method for evaluating the performance of the secondary battery using the capacity. Further, as shown in Patent Document 2 below, an AC voltage is applied to the secondary battery to measure the current flowing through the secondary battery, and the internal impedance of the secondary battery is calculated from the measurement result, and the calculation is performed. There is also a method for evaluating the performance of the secondary battery using the internal impedance. In addition, as shown in Patent Document 3 below, a predetermined current is supplied from the secondary battery, and a voltage drop is measured after a predetermined time. There is also a method for evaluating a large current characteristic (a discharge characteristic of a large current that is instantaneously required). If the secondary battery is evaluated by these methods, the performance of the secondary battery can be determined. If the initial evaluation result is obtained, the degree of deterioration of the secondary battery can also be determined.

JP 2000-306612 A JP 2004-163344 A JP 2003-197271 A

  However, the present inventor has discovered that the current flow between the electrodes inside the secondary battery greatly varies depending on the type of the secondary battery and the degree of deterioration of the secondary battery. Specifically, the current flow between the electrodes inside the secondary battery is such that the largest current flows in a part of the route between the electrodes, and the current that flows away from the route becomes smaller. It has been found that it varies greatly depending on the type of secondary battery and the degree of deterioration of the secondary battery. That is, a secondary battery having a large degree of current reduction is limited to a region where a large current flows inside the secondary battery, and heat generation at that portion is large. Although it is not good, the evaluation from such a viewpoint has not been done so far. In addition, the present inventor has also found that even if there is no significant difference in the items evaluated in the above-described prior art, if the secondary battery deteriorates, there will be a large difference in the way the current flows inside the secondary battery. did. This means that there is a problem that the performance of the secondary battery cannot be accurately evaluated only by the evaluation items shown in the prior art.

  The present invention has been made to solve this problem, and an object of the present invention is to detect how the current flows in the secondary battery and to easily evaluate the performance of the secondary battery from the detection result. It is in providing the evaluation apparatus of a secondary battery. In addition, in the description of each constituent element of the present invention below, in order to facilitate understanding of the present invention, reference numerals of corresponding portions of the embodiment are described in parentheses, but each constituent element of the present invention is The present invention should not be construed as being limited to the configurations of the corresponding portions indicated by the reference numerals of the embodiments.

  In order to achieve the above-described object, the present invention is characterized in that an energization means (65, 66) for applying a voltage between the electrodes (EP1, EP2) of the secondary battery (BA) to flow a current, Magnetic field detection means (10) that is positioned opposite to a plurality of parts, detects a magnetic field generated by current flowing in the plurality of parts, and outputs a signal representing the detected magnetic field, and detection output from the magnetic field detection means Evaluation target physical quantities for calculating, as a plurality of evaluation target physical quantities, the magnitudes of a plurality of currents flowing in a plurality of parts of a secondary battery or the strengths of a plurality of magnetic fields at positions facing the plurality of parts from a signal representing a magnetic field. Among the plurality of evaluation target physical quantities calculated by the calculation means (70, S10 to S80, S102 to S124) and the evaluation target physical quantity calculation means, a plurality of values in the electrolyte region located between the electrodes of the secondary battery The evaluation target physical quantity extraction means (70, S190 to S204, S212) for extracting a plurality of evaluation target physical quantities corresponding to the minutes, and the distribution state of the sizes of the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction means It is provided with graph display means (70, S210 to S220, S224) for creating and displaying a graph.

  In this case, the graph indicating the distribution state of the sizes of the plurality of evaluation target physical quantities is, for example, the size of the evaluation target physical quantity among the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction unit, and the evaluation target physical quantity. It is a relationship curve which shows the relationship with the ratio for which the magnitude | size of the magnitude | size of the evaluation object physical quantity more than the following or below is occupied. In addition, the graph representing the distribution state of the sizes of the plurality of evaluation target physical quantities is the size of the evaluation target physical quantity and the size of the evaluation target physical quantity among the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction unit. The relationship curve which shows the relationship with the ratio which occupies may be sufficient.

  In the present invention configured as described above, the evaluation target physical quantity extracting means includes a plurality of evaluation target physical quantities corresponding to a plurality of portions in the electrolyte region located between the electrodes of the secondary battery (that is, a plurality of evaluation values of the secondary battery). A plurality of currents flowing through the portion or a plurality of magnetic field strengths at positions facing the plurality of portions), and the graph display means displays the distribution state of the extracted plurality of physical quantities to be evaluated. Create and display a graph to represent. In this case, since the strength of the magnetic field is proportional to the magnitude of the current, the operator can grasp the distribution state of the current flowing in each part of the electrolyte region from the graph displayed on the graph display means. That is, as described above, the operator can grasp the degree of decrease in the current with respect to the large current flowing in a part of the route between the electrodes, and can easily evaluate the performance of the secondary battery including the degree of deterioration. become.

  Another feature of the present invention is that the relationship curve is created using, for example, the size of the evaluation target physical quantity divided by the maximum value of the sizes of the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction unit. It is to be a thing. According to this, the axis of the evaluation target physical quantity (the magnitude of the current or the strength of the magnetic field) in the relationship curve is “1” at the maximum in any case. In addition, since the axis of the ratio of the size of the evaluation target object, which is another axis, is also “1” at the maximum, the scale of the axis of the relational curve is constant in any case. Therefore, the secondary battery can be easily evaluated based on the relationship curve regardless of the type of the secondary battery and the applied voltage.

  Another feature of the present invention is that an integral value display means (70, S222, S224) for calculating and displaying an integral value of a function defining the relation curve is further provided. In this case, the integral value of the function that defines the relationship curve has a small evaluation target physical quantity when the ratio of the large evaluation target physical quantity (the magnitude of the current or the strength of the magnetic field) is larger than the ratio of the small evaluation target physical quantity. A different value is taken when the ratio becomes smaller than the ratio. Therefore, the secondary battery including the degree of deterioration can be evaluated depending on the magnitude of the integrated value.

  Another feature of the present invention is that an electrolyte region determining unit (70, S192 to S204) in which the evaluation target physical quantity extracting unit determines an electrolyte region using a plurality of evaluation target physical quantities calculated by the evaluation target physical quantity calculating unit. It is in having. According to this, since the region of the electrolyte part of the secondary battery is automatically detected from the physical quantity to be evaluated, that is, the current distribution or the magnetic field distribution, the operator does not need to specify the electrolyte region of the secondary battery.

  Another feature of the present invention is that the energizing means applies a DC voltage in which an alternating current component having a predetermined frequency is superimposed on the DC voltage between the electrodes of the secondary battery, and the magnetic field detecting means has a frequency equal to the predetermined frequency. Is to detect a magnetic field that changes in order to output a signal representing the detected magnetic field. According to this, the influence of the geomagnetism and the external magnetic field can be eliminated, only the magnetic field generated by the current flowing through the battery can be detected, and the accuracy of evaluation of the secondary battery is improved.

  Another feature of the present invention is that the DC voltage before the AC component is superimposed is within the operating voltage range of the secondary battery. According to this, during the evaluation of the secondary battery, the secondary battery is repeatedly charged and discharged, and the output voltage of the secondary battery after the evaluation is always within the operating voltage range of the secondary battery, and the secondary battery is overcharged. Or it will not be overdischarged.

  Furthermore, in carrying out the present invention, the present invention is not limited to the invention of a secondary battery evaluation device, and can also be implemented as an invention of a secondary battery evaluation method.

It is a whole block diagram of the evaluation apparatus of the secondary battery which concerns on one Embodiment of this invention. It is a schematic perspective view which shows the specific example of the moving mechanism of the stage of FIG. 1, and a magnetic sensor. It is a schematic perspective view of the battery setting table set to the stage. It is a detailed circuit block diagram of the magnetic sensor and sensor signal extraction circuit of FIG. FIG. 2 is a detailed circuit block diagram of the lock-in amplifier of FIG. 1. 3 is a flowchart showing the first half of a data acquisition program executed by the controller of FIG. It is a flowchart which shows the second half part of the said data acquisition program. 2 is a flowchart showing a head portion of an evaluation program executed by the controller of FIG. It is a flowchart which shows the part following FIG. 7A of the said evaluation program. It is a flowchart which shows the part following FIG. 7B of the said evaluation program. It is a flowchart which shows the part following FIG. 7C of the said evaluation program. It is a flowchart which shows the part following FIG. 7D of the said evaluation program. It is a wave form diagram of the energization voltage impressed to the electrode of a rechargeable battery. It is a wave form diagram of the electric current which flows into the secondary battery detected. It is explanatory drawing of the scanning aspect with respect to the secondary battery by a magnetic sensor. It is a figure showing the frequency distribution of the electric current magnitude data Iy of a Y direction. It is a figure for demonstrating the electrode area | region of a lithium ion secondary battery, and the electrolyte area | region through which an electric current flows. It is a figure which shows the electric current which flows through the electrolyte area | region of a lithium ion secondary battery. A current magnitude ratio that represents a ratio of the magnitude of the current to the maximum value of the current flowing in each part in the electrolyte region, and a current that is flowing in each part in the electrolyte region and is greater than or equal to the current magnitude ratio It is a figure of the relationship curve which shows the relationship with the ratio which occupies. It is a figure for demonstrating the computing equation for calculating the integral value of the function represented by the relationship curve of FIG. 14, ie, the area of the part enclosed by the said relationship curve, and X and Y axis. A current magnitude ratio representing a ratio of a current magnitude to a maximum value of a current flowing in each portion in the electrolyte region, and a current magnitude flowing below each current magnitude ratio in the electrolyte region and less than the current magnitude ratio It is a figure of the relationship curve which shows the relationship with the ratio which occupies. A current magnitude ratio representing a ratio of a current magnitude to a maximum value of a current flowing in each portion in the electrolyte region, and a current flowing in each portion in the electrolyte region, and the current magnitude of the current magnitude ratio is It is a figure of the relationship curve which shows the relationship with the ratio occupied.

  Hereinafter, a secondary battery evaluation apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic diagram of the secondary battery evaluation apparatus. This secondary battery evaluation apparatus has a structure that allows a plurality of secondary batteries (lithium ion secondary batteries BA) according to this embodiment to be evaluated at one time. Various structures can be employed accordingly.

  The evaluation apparatus for a secondary battery includes a sensor support base 11 that supports and fixes the magnetic sensor 10, and the sensor support base 11 is moved in the X direction (left and right direction on the paper surface) by the X direction slide mechanism 20 and also in the Y direction. The slide mechanism 30 moves in the Y direction (the direction perpendicular to the paper surface). As shown in detail in FIG. 2, the sensor support 11 is formed of a rectangular flat plate, and supports and fixes the magnetic sensor 10 on the upper surface. The sensor support 11 is supported by a rectangular moving member 21 that forms part of the X-direction slide mechanism 20. The moving member 21 is provided with an adjustment mechanism (not shown) that adjusts the vertical position of the magnetic sensor 10 by displacing the sensor support base 11 up and down. The position is adjusted in the vertical direction.

  On the lower surface of the moving member 21, a convex portion 21a having a predetermined width in the Y direction is provided. The convex portion 21a enters the groove 23a provided on the upper surface of the support member 23 extending in the X direction, and slides in the groove 23a in the X direction. A male screw 24 that extends in the X direction and penetrates the convex portion of the moving member 21 is accommodated in the groove 23 a of the support member 23. A nut (not shown) screwed into the male screw 24 is incorporated in the convex portion 21 a of the moving member 21, and the moving member 21 moves in the X direction by the rotation of the male screw 24. That is, the ball screw mechanism is constituted by the male screw 24 and the nut incorporated in the moving member 21. One end of the male screw 24 is connected to a rotation shaft of an X-direction motor 25 assembled to one end of the support member 23, and the other end of the male screw 24 is rotatably supported by the other end of the support member 23. Thereby, the male screw 24 rotates around the axis by the rotation of the X direction motor 25, and the moving member 21, the sensor support base 11, and the magnetic sensor 10 move in the X direction.

  Convex portions 23 b and 23 c having a predetermined width in the X direction are provided on the lower surface of the support member 23 in the vicinity of both ends in the X direction. These convex portions 23b and 23c enter the grooves 31a and 32a provided on the upper surfaces of the support members 31 and 32 respectively extending in the Y direction, and slide in the grooves 31a and 32a in the Y direction. ing. In the groove 31a of the support member 31, a male screw 33 extending in the Y direction and passing through the convex portion 23b of the support member 23 is accommodated. A nut (not shown) screwed into the male screw 33 is incorporated in the convex portion 23 b of the support member 23, and the support member 23 is moved in the Y direction by the rotation of the male screw 33. That is, the ball screw mechanism is configured by the male screw 33 and the nut incorporated in the support member 23. One end of the male screw 33 is connected to a rotation shaft of a Y-direction motor 34 assembled to one end of the support member 31, and the other end of the male screw 33 is rotatably supported by the other end of the support member 31. Thereby, the male screw 33 rotates around the axis by the rotation of the Y direction motor 34, and the support member 23 moves in the Y direction together with the moving member 21, the sensor support 11 and the magnetic sensor 10.

  In addition, the evaluation apparatus for a secondary battery includes a stage 40 on which the lithium ion secondary battery BA is placed. The stage 40 includes a frame 42 disposed above the support members 31 and 32 via connecting portions 41 a, 41 b, 41 c and 41 d extending upward from the respective end portions of the support members 31 and 32. Yes. The frame 42 includes outer frames 42a and 42b positioned above the support members 31 and 32, and outer frames 42c and 42d respectively connecting both ends of the outer frames 42a and 42b. The outer frames 42a, 42b, 42c, and 42d are integrally provided with an inner frame 42e that connects the outer frames 42a, 42b, 42c, and 42d to form a rectangular window. Steps are provided in the windows formed by the outer frames 42a, 42b, 42c, 42d and the inner frame 42e, and the battery setting table 50 is assembled to each of these windows.

  As shown in FIG. 3, the battery setting table 50 includes a support plate 51 having a size that is mounted on and mounted on a rectangular window of the stage 40. The support plate 51 is provided with a rectangular recess 51a in which the lithium ion secondary battery BA is set. If the lithium ion secondary battery BA is not disposed on the side surface where the electrodes 52a and 52b are opposed to each other, the corner portion where the two adjacent side surfaces not having the electrodes 52a and 52b of the lithium ion secondary battery BA intersect is X The two side surfaces are arranged so as to be in contact with the end surface of the recess 51a so as to be closest to the origin position of the -Y coordinate. On the other hand, when the electrodes 52a and 52b of the lithium ion secondary battery BA are respectively disposed on the opposite side surfaces, one side surface on which the electrodes 52a and 52b are not disposed extends in the X direction or the Y direction of the recess 51a. The lithium ion secondary battery BA is brought to the origin of the XY coordinates by bringing it into contact with one end face and bringing the side face having one of the electrodes 52a, 52b as close as possible to the other end face extending in the X direction or Y direction. Position closest to the location. The electrode 52a is a positive electrode, and the electrode 52b is a negative electrode. When the battery setting table 50 is assembled to the window of the stage 40 and the lithium ion secondary battery BA is set to the battery setting table 50, the magnetic sensor 10 is positioned below the lithium ion secondary battery BA. ing. On the upper surface of the support plate 51, handles 53 for carrying the battery setting table 50 are also provided.

  Returning to the description of FIG. 1, an encoder 25 a that detects the rotation of the X-direction motor 25 and outputs a rotation signal representing the rotation is incorporated in the X-direction motor 25. This rotation signal is a pulse train signal that alternately switches between a high level and a low level each time the X-direction motor 25 rotates by a predetermined minute angle, and is phase-shifted by π / 2 to identify the rotation direction. The A phase signal and the B phase signal. The rotation signal is output to the X direction position detection circuit 61 and the X direction feed motor control circuit 62. The X-direction position detection circuit 61 counts up or down the number of pulses of the rotation signal in accordance with the rotation direction of the X-direction motor 25, and the X direction of the sensor support 11 with respect to the stage 40 by the X-direction motor 25 from the count value. The position (that is, the X-direction position of the magnetic sensor 10) is detected, and the detected X-direction position is output to the X-direction feed motor control circuit 62 and a controller 70 described later. The X-direction feed motor control circuit 62 controls driving and stopping of the X-direction motor 25 according to instructions from the controller 70. When driving the X-direction motor 25, the X-direction feed motor control circuit 62 rotates the X-direction motor 25 at a predetermined rotation speed using a rotation signal from the encoder 25a.

  The initial setting of the count value in the X-direction position detection circuit 61 is performed according to an instruction from the controller 70 when the power is turned on. That is, the controller 70 instructs the X-direction feed motor control circuit 62 to move to the X-direction limit position corresponding to the initial position of the sensor support 11 and the X-direction position detection circuit 61 to perform initial setting when the power is turned on. In response to this instruction, the X-direction feed motor control circuit 62 drives the X-direction motor 25 to move the sensor support 11 to the X-direction limit position corresponding to the initial position. The X-direction position detection circuit 61 continues to input a rotation signal from the encoder 25a in the X-direction motor 25 while the sensor support base 11 is moving in the X direction. When the sensor support 11 reaches the X direction limit position corresponding to the initial position and the rotation of the X direction motor 25 stops, the X direction position detection circuit 61 detects the stop of the input of the rotation signal from the encoder 25a, The count value is reset to “0”. At this time, the X-direction position detection circuit 61 outputs a signal for stopping output to the X-direction feed motor control circuit 62, whereby the X-direction feed motor control circuit 62 outputs a drive signal to the X-direction motor 25. To stop. Thereafter, when the X direction motor 25 is driven, the X direction position detection circuit 61 counts up or down the number of pulses of the rotation signal in accordance with the rotation direction of the X direction motor 25, and based on the count value. Then, the X direction position of the sensor support 11 is calculated, and the calculated X direction position is continuously output to the X direction feed motor control circuit 62 and the controller 70.

  In the Y-direction motor 34, an encoder 34a that detects the rotation of the Y-direction motor 34 and outputs a rotation signal indicating the rotation is incorporated in the same manner as the X-direction motor 25. This rotation signal is output to the Y direction position detection circuit 63 and the Y direction feed motor control circuit 64. The Y-direction position detection circuit 63 counts up or counts down the number of pulses of the rotation signal in accordance with the rotation direction of the Y-direction motor 34, and the Y-direction position of the sensor support 11 by the Y-direction motor 34 (ie, the count value) The Y position of the magnetic sensor 10 is detected, and the detected Y direction position is output to the Y direction feed motor control circuit 64 and the controller 70. The Y-direction feed motor control circuit 64 controls the driving and stopping of the Y-direction motor 34 according to instructions from the controller 70 as in the case of the X-direction feed motor control circuit 62. When driving the Y-direction motor 34, the Y-direction feed motor control circuit 64 rotates the Y-direction motor 34 at a predetermined speed using a rotation signal from the encoder 34a.

  The initial setting of the count value in the Y-direction position detection circuit 63 is also performed by an instruction from the controller 70 when the power is turned on. That is, the controller 70 instructs the Y-direction feed motor control circuit 64 to move to the Y-direction limit position corresponding to the initial position of the sensor support base 11 and the Y-direction position detection circuit 63 to perform initial setting when the power is turned on. In response to this instruction, the Y-direction feed motor control circuit 64 drives the Y-direction motor 34 to move the sensor support 11 to the Y-direction limit position corresponding to the initial position. The Y-direction position detection circuit 63 continues to input a rotation signal from the encoder 34a in the Y-direction motor 34 while the sensor support 11 is moving in the Y direction. When the sensor support base 11 reaches the Y-direction limit position corresponding to the initial position and the rotation of the Y-direction motor 34 stops, the Y-direction position detection circuit 63 detects the stop of input of the rotation signal from the encoder 34a, The count value is reset to “0”. At this time, the Y-direction position detection circuit 63 outputs a signal for stopping the output to the Y-direction feed motor control circuit 64, whereby the Y-direction feed motor control circuit 64 outputs a drive signal to the Y-direction motor 34. To stop. Thereafter, when the Y direction motor 34 is driven, the Y direction position detection circuit 63 counts up or down the number of pulses of the rotation signal in accordance with the rotation direction of the Y direction motor 34, and based on the count value. The Y-direction position of the sensor support 11 is calculated and the calculated Y-direction position is continuously output to the Y-direction feed motor control circuit 64 and the controller 70.

  The secondary battery evaluation device further includes an energization signal supply circuit 65, an energization circuit 66, an energization selection circuit 67, a sensor signal extraction circuit 68, a lock-in amplifier 69, and a controller 70. The energization signal supply circuit 65 includes a sine wave oscillator and a rectangular wave conversion circuit, and is controlled by the controller 70 to supply a sine wave signal oscillated by the sine wave oscillator to the energization circuit 66 as an energization signal. The energization signal is a signal that changes from positive to negative with reference to “0”, and the frequency is, for example, about several tens of hertz to several hundreds of hertz. The energization signal supply circuit 65 generates a rectangular wave signal that changes positively and negatively around “0” in synchronization with the energization signal by converting the energization signal composed of the sine wave signal by the rectangular wave conversion circuit. The reference signal is output to the lock-in amplifier 69.

  The energization circuit 66 is also controlled by the controller 70 and energizes the lithium ion secondary battery BA via the energization selection circuit 67. In this case, the energization circuit 66 adds a positive offset voltage to a sine wave signal that changes positively or negatively with respect to “0” supplied from the energization signal supply circuit 65, and changes in a sine wave shape with the offset voltage as the center. Then, it is converted into an energization signal that always changes within the positive range, and is supplied to the anode 52a of the lithium ion secondary battery BA through the connection line L1. On the other hand, the ground side terminal of the energization circuit 66 is connected to the cathode 52b of the lithium ion secondary battery BA. That is, a direct current voltage on which an alternating current component having a predetermined frequency is superimposed is applied between the anode 52a and the cathode 52b of the lithium ion secondary battery BA. Note that the DC voltage (energization voltage) on which the AC component is superimposed varies within the operating voltage range of the lithium ion secondary battery BA. That is, the maximum voltage of the energization voltage is not more than the upper limit value of the charging voltage of the lithium ion secondary battery BA, and the minimum voltage is not less than the lower limit value of the discharge voltage of the lithium ion secondary battery BA.

  Specifically, for example, when the upper limit of the charging voltage of the lithium ion secondary battery BA is 4.1 v and the lower limit of the discharge voltage is 2.9 v, a voltage in the vicinity of these (for example, 3.5 v) An AC signal is superimposed on (see FIG. 8). In particular, even if the AC signal is not superimposed on the voltage in the vicinity of the intermediate point, the energized voltage on which the AC signal is superimposed is always between the upper limit of the charging voltage and the lower limit of the discharging voltage of the lithium ion secondary battery BA. For example, an appropriate voltage can be used. Further, the amplitude of the superimposed AC signal is also set so that the energization voltage as a result of the superposition is always between the upper limit of the charging voltage of the lithium ion secondary battery BA and the lower limit of the discharging voltage.

  In this case, when a voltage higher than the current output voltage is applied to the lithium ion secondary battery BA, the current flows in the direction of the current by the energized voltage, that is, the lithium ion secondary battery BA is charged. Further, when a voltage lower than the current output voltage is applied to the lithium ion secondary battery BA, a current flows in a direction opposite to the direction of the current due to the energized voltage, that is, the lithium ion secondary battery BA is discharged. For this reason, the lithium ion secondary battery BA repeats charging and discharging by the application of the energization voltage. FIG. 9 shows the current intensity change at this time in the direction of the current during charging. When a magnetic field component having the same frequency as the energized voltage is detected by the lock-in amplifier 69 and converted into a current component, the value indicated by the arrow is detected as a positive value. This is as if the current flowing in the charging direction was detected by the energization voltage. As a result, as will be described in detail later, the lithium ion secondary battery BA can be evaluated by grasping the distribution state of the current magnitude obtained by obtaining the detected values at a plurality of positions.

  The energization selection circuit 67 supplies the energization voltage supplied from the energization circuit 66 to the lithium ion secondary battery BA via the connection line L1. That is, the plurality of connection lines L1 are respectively connected to the positive electrode 52a and the negative electrode 52b provided in the lithium ion secondary battery BA. In this case, the energization selection circuit 67 is controlled by the controller 70 and energizes one lithium ion secondary battery BA designated by the controller 70 among the plurality of set lithium ion secondary batteries BA.

  Next, the magnetic sensor 10 will be described. As shown in FIG. 4, the magnetic sensor 10 includes an X-direction magnetic sensor 10A that detects a magnetic field in the X direction and a Y-direction magnetic sensor 10B that detects a change in the magnetic field in the Y direction. The X-direction magnetic sensor 10A is constituted by a bridge circuit composed of resistors r11, r12, r13 and a magnetoresistive element MR1, and between the connection point of the resistors r11, r13 and the connection point of the resistor r12 and the magnetoresistive element MR1. In addition, voltages + V and −V are applied from a constant voltage supply circuit 68a (described later) of the sensor signal extraction circuit 68. In the X-direction magnetic sensor 10A, a voltage between the connection point of the resistor r13 and the magnetoresistive element MR1 and the connection point between the resistors r11 and r12 is output as an X-direction magnetic detection signal. The values of the resistors r11, r12, r13 are the same and are equal to the resistance value of the magnetoresistive element MR1 when the magnetic field strength is “0”. As a result, the X direction magnetic field detection signal is a voltage that changes positively or negatively in proportion to the magnitude of the magnetic field in the X direction with reference to approximately “0” due to the positive or negative change in the X direction magnetic field with respect to approximately “0”. Signal.

  The Y-direction magnetic sensor 10B is composed of a bridge circuit composed of resistors r21, r22, r23 and a magnetoresistive element MR2, and between the connection point of the resistors r21, r22 and the connection point of the resistor r23 and the magnetoresistive element MR2. In addition, voltages + V and −V are applied from a constant voltage supply circuit 68b, which will be described later, of the sensor signal extraction circuit 68. In the Y direction magnetic sensor 10B, a voltage between the connection point of the resistor r22 and the magnetoresistive element MR2 and the connection point between the resistors r21 and r23 is output as a Y direction magnetic detection signal. The values of the resistors r21, r22, r23 are the same, and are equal to the resistance value of the magnetoresistive element MR2 when the magnetic field strength is “0”. As a result, the positive and negative changes in the magnetic field in the Y direction with respect to “0” as a reference cause the Y direction magnetic detection signal to change in positive and negative in proportion to the magnitude of the magnetic field in the Y direction with reference to “0”. Signal.

  The sensor signal extraction circuit 68 includes constant voltage supply circuits 68a and 68b and amplifiers 68c and 68d. The constant voltage supply circuits 68a and 68b supply constant voltages + V and −V to the X-direction magnetic sensor 10A and the Y-direction magnetic sensor 10B according to instructions from the controller 70. The amplifiers 68c and 68d amplify the X direction magnetic detection signal and the Y direction magnetic detection signal, respectively, and output the amplified signals to the lock-in amplifier 69.

  As shown in detail in FIG. 5, the lock-in amplifier 69 includes a high-pass filter 69a that inputs an X-direction magnetic detection signal supplied from the X-direction magnetic sensor 10A via the amplifier 68c, and an amplifier 68d from the Y-direction magnetic sensor 10B. And a high-pass filter 69b for inputting a Y-direction magnetic detection signal supplied via the. The high-pass filters 69a and 69b remove unnecessary components other than the signal component proportional to the strength of the magnetic field included in the X-direction magnetic detection signal and the Y-direction magnetic detection signal, and change the signal around the ground level. To.

  The output of the high pass filter 69a is supplied to the phase detection circuits 69d and 69e via the amplifier 69c. The phase detection circuits 69d and 69e are each configured by a multiplier. The phase detection circuit 69d multiplies the X direction magnetic detection signal supplied via the high pass filter 69a and the amplifier 69c by the reference signal from the energization signal supply circuit 65 and outputs the result to the low pass filter 69f. The phase detection circuit 69e adds a delayed reference signal obtained by delaying the phase of the reference signal from the energization signal supply circuit 65 by 90 degrees by the phase shift circuit 69g to the X-direction magnetic detection signal supplied via the high-pass filter 69a and the amplifier 69c. Multiply and output to low pass filter 69h. Thus, a component synchronized with the energization signal (reference signal) of the X-direction magnetic detection signal is supplied to the low-pass filter 69f, and the low-pass filter 69f performs low-pass filter processing on the supplied component signal and supplies the X-direction magnetic detection signal A signal indicating the magnitude of the component synchronized with the signal is output. The low-pass filter 69h is supplied with a component synchronized with a signal (delayed reference signal) delayed in phase by 90 degrees from the energization signal of the X-direction magnetic detection signal, and the low-pass filter 69h performs low-pass filter processing on the supplied component signal. A signal representing the magnitude of the component synchronized with the signal delayed in phase by 90 degrees from the energization signal of the X direction magnetic detection signal is output.

  The output of the high pass filter 69b is supplied to the phase detection circuits 69j and 69k via the amplifier 69i. Low-pass filters 69m and 69n are connected to the phase detection circuits 69j and 69k. The phase detection circuits 69j and 69k and the low-pass filters 69m and 69n are configured similarly to the phase detection circuits 69d and 69e and the low-pass filters 69f and 69h described above. As a result, a component synchronized with the energization signal (reference signal) of the Y-direction magnetic detection signal is supplied to the low-pass filter 69m, and the low-pass filter 69m performs low-pass filter processing on the supplied component signal, A signal indicating the magnitude of the component synchronized with the signal is output. The low-pass filter 69n is supplied with a component synchronized with a signal (delayed reference signal) delayed in phase by 90 degrees from the energization signal of the Y-direction magnetic detection signal, and the low-pass filter 69n performs low-pass processing on the supplied component signal. A signal indicating the magnitude of the component synchronized with the signal delayed by 90 degrees from the energization signal of the direction magnetic detection signal is output. The low-pass filters 69f, 69h, 69m, and 69n are connected to A / D converters 69o, 69p, 69q, and 69r, respectively. The A / D converters 69o, 69p, 69q, and 69r respectively A / D convert the signals from the low-pass filters 69f, 69h, 69m, and 69n and supply the signals to the controller 70 at predetermined time intervals.

  Returning to the description of FIG. 1 again, the controller 70 is an electronic control unit including a microcomputer including a CPU, a ROM, and a RAM, a storage device such as a hard disk and a nonvolatile memory, an input / output interface, and the like. The controller 70 controls the operation of the secondary battery evaluation device by executing the data acquisition program of FIGS. 6A and 6B and the evaluation program of FIGS. 7A and 7E stored in the storage device. Connected to the controller 70 are an input device 71 for an operator to instruct various parameters, processing, and the like, and a display device 72 for visually informing the operator of the operation status and the like.

  Next, the operation of the secondary battery evaluation apparatus configured as described above will be described. As shown in FIG. 1, the operator assembles a plurality of battery setting tables 50 on the frame 42 of the stage 40 and sets a lithium ion secondary battery BA to be inspected on the battery setting table 50. Then, the worker connects the positive electrode 52a and the negative electrode 52b of the lithium ion secondary battery BA to the energization selection circuit 67 through the connection line L1. In this state, when the secondary battery evaluation device is powered on, as described above, the X-direction feed motor control circuit 62 and the Y-direction feed motor control circuit 64 cause the sensor support 11 ( That is, the magnetic sensor 10) is moved to the limit positions in the X direction and the Y direction, and the X direction position detection circuit 61 and the Y direction position detection circuit 63 set the detected X direction position and Y direction position to initial values.

  Thereafter, the operator operates the input device 71 to provide the lithium ion secondary battery BA set on the battery setting table 50, and the length of the lithium ion secondary battery BA in the X direction and the Y direction. And the number of electrodes are input in the order of evaluation. At this time, if the length in the X direction and the length in the Y direction are set such that the corners of the lithium ion secondary battery BA are in contact with the corners of the recesses 51a of the battery setting table 50, the lithium ion secondary battery can be used. What is necessary is just to input the length in the X direction and the length in the Y direction of the BA itself. Otherwise, the length from the corner of the recess 51a to each end of the lithium ion secondary battery BA is set as the length in the X direction and Enter as the length in the Y direction. The order of evaluation is set so as to reciprocate from the origin position in the X and Y axis directions to the X axis direction positive side and the negative side and to the Y axis direction positive side, for example. Thereafter, the operator operates the input device 71 to instruct the controller 70 to start evaluation of the lithium ion secondary battery BA. In response to this instruction, the controller 70 starts executing the data acquisition program in step S10 of FIG. 6A, and sets the variable s to “1” in step S12. This variable s designates each of the lithium ion secondary batteries BA set on the stage 40 via the battery setting table 50. For all the lithium ion secondary batteries BA, 1, 2, 3. A variable s that changes in the order of evaluation of smax is assigned.

  After the processing of step S12, the controller 70 selects the lithium ion secondary battery BA specified by the variable s in step S14, and supplies the electrification selection circuit 67 so as to energize the selected lithium ion secondary battery BA. An instruction signal is output. The energization selection circuit 67 selects the lithium ion secondary battery BA that is energized through the connection L1. Next, in step S16, the controller 70 initializes the variable n to “0” and initializes the variables m and a to “1”. The variables n and m are variables indicating the scanning positions of the magnetic sensor 10 in the X direction and the Y direction with respect to the selected lithium ion secondary battery BA. The variable a represents a state where the center position of the magnetic sensor 10 is moved to the X axis direction positive side by “1”, and the center position of the magnetic sensor 10 is moved to the X axis direction negative side by “−1”. It represents the state. Hereinafter, the center position of the magnetic sensor 10 is referred to as an inspection position.

  In this case, as shown in FIG. 10, the magnetic sensor 10 changes the end position represented by the end value Xmax in the X direction from the initial position specified by the initial values Xs and Ys for each lithium ion secondary battery BA. The movement is controlled by a predetermined minute value ΔX until it exceeds. When the end position in the X direction is reached, the magnetic sensor 10 is controlled to move by a predetermined minute value ΔY in the Y direction, and thereafter, the movement is controlled by a minute value ΔX from the end position in the X direction to the start position in the X direction. The Again, the magnetic sensor 10 is controlled to move by a minute value ΔY in the Y direction, and is controlled to move by a minute value ΔX from the start position to the end position in the X direction. Thus, the magnetic sensor 10 moves in the Y direction while reciprocating in the X direction, and scans the lithium ion secondary battery BA. The initial values Xs and Ys are determined and stored in advance for each lithium ion secondary battery BA specified by the variable s. The end values Xmax and Ymax are calculated and stored in advance using the input X-direction length and Y-direction length for each lithium ion secondary battery BA specified by the variable s. Further, the minute values ΔX and ΔY are extremely small compared to the vertical and horizontal lengths of the lithium ion secondary battery BA (values slightly smaller than Xmax−Xs and Ymax−Ys), and are predetermined and stored values. .

  After the processing in step S16, the controller 70 moves the magnetic sensor 10 in the X-axis direction to the X-direction feed motor control circuit 62 in step S18, and the lithium ion secondary whose inspection position is specified by the variable s. The battery BA is instructed to be the initial position represented by the initial value Xs in the X-axis direction, and the magnetic sensor 10 is moved in the Y-axis direction to the Y-direction feed motor control circuit 64 so that the inspection position is a variable s. Is designated to be the initial position represented by the initial value Ys in the Y-axis direction of the lithium ion secondary battery BA designated by. In response to this instruction, the X-direction feed motor control circuit 62 inputs the X-direction detection position (inspection position in the X-axis direction) from the X-direction position detection circuit 61, and the X-direction detection position matches the initial value Xs. The X direction motor 25 is driven and controlled until The Y-direction feed motor control circuit 64 inputs the Y-direction detection position (inspection position in the Y-axis direction) from the Y-direction position detection circuit 63, and controls the Y-direction motor 34 until the Y-direction detection position matches the initial value Ys. Drive control.

  After the process of step S18, the controller 70 instructs the operation start of the energization signal supply circuit 65 in step S20. In response to this instruction, the energization signal supply circuit 65 supplies a sinusoidal energization signal to the energization circuit 66 and starts supplying a rectangular wave reference signal synchronized with the energization signal to the lock-in amplifier 69. Next, the controller 70 instructs the operation start of the energization circuit 66 in step S22. In response to this instruction, the energization circuit 66 converts the supplied energization signal into an energization signal (see FIG. 8) that changes within the operating voltage range of the lithium ion secondary battery BA and outputs the energization signal to the energization selection circuit 67. To do. The energization selection circuit 67 supplies the energization signal supplied from the energization circuit 66 to the lithium ion secondary battery BA designated by the process of step S14. As a result, the designated lithium ion secondary battery BA starts flowing an energization signal to the positive electrode, the negative electrode, and the electrolyte region while repeating charge and discharge. Next, the controller 70 instructs the operation start of the sensor signal extraction circuit 68 in step S24. In response to this instruction, the constant voltage supply circuits 68a and 68b in the sensor signal extraction circuit 68 start to supply the constant voltage signals + V and −V to the X direction magnetic sensor 10A and the Y direction magnetic sensor 10B. Thereby, the X direction magnetic detection signal and the Y direction magnetic detection signal by the X direction magnetic sensor 10A and the Y direction magnetic sensor 10B start to be supplied to the lock-in amplifier 69 via the amplifiers 68c and 68d, respectively.

  The X direction magnetic detection signal and the Y direction magnetic detection signal will be described. By charging / discharging the lithium ion secondary battery BA by supplying the energization signal to the lithium ion secondary battery BA specified by the variable s described above, the anode, cathode and electrolyte in the lithium ion secondary battery BA are charged and discharged. (See FIG. 9). Due to this current, a magnetic field corresponding to the current is generated in the vicinity of the front and back surfaces of the lithium ion secondary battery BA. Then, the X direction magnetic sensor 10A starts outputting a voltage proportional to the magnitude of the magnetic field Hx in the X direction as an X direction magnetic detection signal. The Y-direction magnetic sensor 10B starts outputting a voltage proportional to the magnitude of the magnetic field Hy in the Y direction as a Y-direction magnetic detection signal. These X direction magnetic detection signal and Y direction magnetic detection signal are signals that change sinusoidally because the current changes sinusoidally.

  In the lock-in amplifier 69, the input X-direction magnetic detection signal is supplied to the phase detection circuits (multipliers) 69d and 69e via the high-pass filter 69a and the amplifier 69c, respectively, and the input Y-direction magnetic detection signal. Are supplied to phase detection circuits (multipliers) 69j and 69k through a high-pass filter 69b and an amplifier 69i, respectively. A rectangular wave reference signal from the energization signal supply circuit 65 is supplied to the phase detection circuits 69d and 69j. The phase detection circuits 69e and 69k are supplied with a delayed reference signal obtained by delaying the phase of the reference signal by 90 degrees by the phase shift circuit 69g. Then, the phase detection circuits 69d and 69e multiply the X direction magnetic detection signal supplied via the amplifier 69c by the reference signal and the delayed reference signal, respectively, and the multiplied signals are A / A via the low pass filters 69f and 69h. The D converters 69o and 69p are supplied. The phase detection circuits 69j and 69k multiply the Y direction magnetic detection signal supplied via the amplifier 69i by the reference signal and the delayed reference signal, respectively, and A / D convert the multiplied signals via the low pass filters 69m and 69n. It supplies to the devices 69q and 69r, respectively.

  Here, the low-pass filters 69f, 69h, 69j and 69k function to output a signal representing the magnitude of the component of the supplied signal, that is, a signal representing the magnitude proportional to the amplitude of the sinusoidal signal. Therefore, the A / D converter 69o is supplied with a signal indicating the magnitude of the signal component synchronized with the reference signal of the X direction magnetic detection signal. The A / D converter 69p is supplied with a signal representing the magnitude of the signal component whose phase is delayed by 90 degrees from the reference signal of the X direction magnetic detection signal. A signal representing the magnitude of the signal component synchronized with the reference signal of the Y-direction magnetic detection signal is supplied to the A / D converter 69q. The A / D converter 69r is supplied with a signal representing the magnitude of the signal component whose phase is delayed by 90 degrees from the reference signal of the Y-direction magnetic detection signal. The A / D converters 69o, 69p, 69q, and 69r sample the supplied signals at predetermined intervals, perform A / D conversion, and supply the A / D converted sampling data to the controller 70. Therefore, the sampling data representing the magnitude of each signal component every predetermined time is supplied to the controller 70 every predetermined time.

  After the process of step S24, the controller 70 adds the variable a to the variable n in step S26. In this case, since the variable n before the process of step S26 is “0” and the variable a is “1”, the variable n is changed to “1”. After the processing of step S26, the controller 70 fetches the sampling data supplied from the A / D converters 69o, 69p, 69q, 69r of the lock-in amplifier 69 in step S28, and fetches the sampling data fetched in step S30. It is determined whether or not the number of sampling data has reached a predetermined number K. The predetermined number K is set to a value representing the number of sampling data of several to several tens, for example. If the number of each sampling data has not reached the predetermined number K, the controller 70 makes a “No” determination at step S30, and at step S28, from the A / D converters 69o, 69p, 69q, 69r to the next. Takes output sampling data. When the number of sampling data fetched from the A / D converters 69o, 69p, 69q, 69r reaches a predetermined number K, the controller 70 determines “Yes” in step S30, and after step S32 Execute the process. The sampling data fetched in step S28 is stored in the RAM as a sampling data group designated by the variable s and the variables n and m.

  Specifically, a predetermined number K of sampling data fetched from the A / D converter 69o, that is, a predetermined number K of data representing the magnitude of the signal component synchronized with the reference signal of the X-direction magnetic detection signal is represented by the variable s. Is stored in the RAM as a sampling data group Sx1 (n, m) of the lithium ion secondary battery BA designated by. The predetermined number K of sampling data taken from the A / D converter 69p, that is, the predetermined number K of data representing the magnitude of the signal component synchronized with the delayed reference signal of the X direction magnetic detection signal is the same lithium ion 2 as described above. The data is stored in the RAM as the sampling data group Sx2 (n, m) of the secondary battery BA. The predetermined number K of sampling data taken from the A / D converter 69p, that is, the predetermined number K of data representing the magnitude of the signal component synchronized with the reference signal of the Y-direction magnetic detection signal is the same as the lithium ion secondary as described above. The sampling data group Sy1 (n, m) of the battery BA is stored in the RAM. The predetermined number K of sampling data fetched from the A / D converter 69r, that is, the predetermined number K of data representing the magnitude of the signal component synchronized with the delayed reference signal of the Y direction magnetic detection signal is the same lithium ion 2 as described above. The data is stored in the RAM as a sampling data group Sy2 (n, m) of the secondary battery BA. In this case, the variables n and m are both “1”.

  After the processing of steps S28 and S30, the controller 70 determines whether or not the variable a is “1” in step S32. Since the variable a is initially set to “1”, the controller 70 determines “Yes” in step S32 in this case, and the value Xs + n · ΔX is the end value Xmax in the X-axis direction in step S34. It is judged whether it is larger than. The end value Xmax is an end value stored in advance in the X-axis direction for the lithium ion secondary battery BA specified by the variable s. The value Xs + n · ΔX is a value obtained by multiplying a predetermined value ΔX representing the scanning interval in the X-axis direction by the variable n and adding the initial value Xs, and the next measurement position in the X-axis direction (scanning position in the X-axis direction) (See FIG. 10). If the value Xs + n · ΔX is equal to or less than the end value Xmax, the controller 70 determines “No” in step S34, and in step S36, the controller 70 sets the measurement position of the magnetic sensor 10 in the X-direction feed motor control circuit 62. Instructs to move to the X axis direction positive side. Thereby, the X-direction feed motor control circuit 62 starts to move the measurement position by the magnetic sensor 10 to the X axis direction positive side by operating the X direction motor 25.

  Next, the controller 70 inputs the X direction position from the X direction position detection circuit 61 in step S38, and whether or not the X direction position input in step S40 has reached the next measurement position in the X axis direction. That is, it is determined whether or not the value indicating the position in the X direction is equal to or greater than the value Xs + n · ΔX. The controller 70 continues to determine “No” in step S40 until the X-direction position input from the X-direction position detection circuit 61 reaches the next measurement position in the X-axis direction, and the processing in steps S38 and S40. Repeatedly. When the X-direction position input from the X-direction position detection circuit 61 reaches the next measurement position in the X-axis direction, the controller 70 determines “Yes” in step S40, and in step S42, the X-direction feed motor control circuit. 62 is instructed to stop the movement of the measurement position of the magnetic sensor 10 to the positive side in the X-axis direction. Thereby, the X-direction feed motor control circuit 62 stops the operation of the X-direction motor 25 and stops the movement of the measurement position by the magnetic sensor 10 to the positive side in the X-axis direction. As a result, the magnetic sensor 10 starts to detect the magnetic field at the X-axis direction position represented by the value Xs + n · ΔX and the Y-axis direction initial value Ys.

  After the process of step S42, the controller 70 returns to step S26, adds the variable a (in this case, a = 1) to the variable n by the process of step S26, and performs the sampling data of the above-described steps S28 and S30. Execute capture processing. By the processing of these steps S28 and S30, the measurement result of the magnetic sensor 10 of the X-axis direction position (the next irradiation position) represented by the value Xs + (n−1) · ΔX and the Y-axis direction initial value Ys is obtained. Sampling data is newly stored in the RAM. Specifically, a predetermined number K of sampling data representing the magnitudes of the signal components synchronized with the reference signal and the delayed reference of the X direction magnetic detection signal are the sampling data of the lithium ion secondary battery BA specified by the variable s. Groups Sx1 (n, m) and Sx2 (n, m) are stored in the RAM. In addition, a predetermined number K of sampling data representing the magnitudes of the signal components synchronized with the reference signal and the delayed reference signal of the Y-direction magnetic detection signal are the sampling data group Sy1 of the lithium ion secondary battery BA specified by the variable s. (n, m) and Sy2 (n, m) are stored in the RAM. In this case, the variable n is “2” and the variable m is “1”.

  Then, the controller 70 changes the measurement position to X by performing the processing of steps S26 to S42 until the value Xs + n · ΔX representing the next measurement position in the X-axis direction (scanning position in the X-axis direction) becomes larger than the end value Xmax. Sampling data is taken in while moving by a predetermined value ΔX to the positive side in the axial direction and increasing the variable n by “1”. When the value Xs + n · ΔX representing the next measurement position in the X-axis direction becomes larger than the end value Xmax, the controller 70 determines “Yes” in step S34 and advances the program to step S54 in FIG. 6B. . In this state, the sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) (n = n = n) of the lithium ion secondary battery BA designated by the variable s. 1, 2, 3... N, m = 1) are stored in the RAM. The value N is the value of the variable n related to the sampling data group at the measurement position immediately before the end value Xmax, and represents the number of measurement positions in the X-axis direction.

  In step S54, the controller 70 instructs the Y-direction feed motor control circuit 64 to move the measurement position by the magnetic sensor 10 to the Y axis direction positive side. Thereby, the Y-direction feed motor control circuit 64 starts to move the measurement position by the magnetic sensor 10 to the Y axis direction positive side by operating the Y direction motor 34. Next, the controller 70 inputs the Y-direction position from the Y-direction position detection circuit 63 in step S56, and whether the Y-direction position input in step S58 has reached the next measurement position Ys + m · ΔY in the Y-axis direction. Determine whether or not. The next measurement position Ys + m · ΔY in the next Y-axis direction is multiplied by a variable m to a predetermined value ΔY representing the scanning interval in the Y-axis direction, similarly to the next measurement position Xs + n · ΔX in the X-axis direction. (See FIG. 10). The controller 70 continues to make a “No” determination at step S58 until the Y-direction position input from the Y-direction position detection circuit 63 reaches the next measurement position in the Y-axis direction, and the processing of steps S56 and S58. Repeatedly. When the Y-direction position input from the Y-direction position detection circuit 63 reaches the next measurement position in the Y-axis direction, the controller 70 determines “Yes” in step S58, and the Y-direction feed motor control circuit in step S60. 64 is instructed to stop the movement of the measurement position by the magnetic sensor 10 to the positive side in the Y-axis direction. Thereby, the Y-direction feed motor control circuit 62 stops the operation of the Y-direction motor 34 and stops the movement of the measurement position by the magnetic sensor 10 to the Y axis direction positive side. As a result, the magnetic sensor 10 is represented by a value Xs + (n−1) · ΔX (= Xs + (N−1) · ΔX) and an X-axis direction position, and a value Ys + m · ΔY (= Ys + ΔY). Start measuring the magnetic field at the position in the Y-axis direction.

  After the process of step S60, the controller 70 inputs the Y-direction position from the Y-direction position detection circuit 63 in step S62, and the scanning in the Y-axis direction in which the input Y-direction position is represented by the end value Ymax is completed. It is determined whether or not the position has been exceeded. The end value Ymax is a prestored end value in the Y-axis direction related to the lithium ion secondary battery BA specified by the variable s. If the position in the Y direction does not exceed the scanning end position, the controller 70 determines “No” in step S62, adds “1” to the variable m in step S64, and sets the variable a in step S66. Multiply by “−1”. In this case, the variable m becomes “2” by the process of step S64, and the variable a becomes “−1” by the process of step S66. The variable n is kept at the value N. After the process of step S66, the controller 70 returns to step S28 of FIG. 5A, and each of the K sampling data groups Sx1 (N, 2), Sx2 (N, 2), Sy1 (N, 2) and Sy2 (N, 2) are fetched from the lock-in amplifier 69 and stored.

  After the processing of steps S28 and S30, the controller 70 determines whether or not the variable a is “1” in step S32. In this case, since the variable a is set to “−1” by the process of step S66, the controller 70 determines “No” in step S32, and the value Xs + (n−2) in step S44. ) · ΔX is determined whether or not it is smaller than the initial value Xs in the X-axis direction. In this case, the variable n is N, and the value Xs + (n−2) · ΔX is a value representing the second detection position from the right end in FIG. If the value Xs + (n−2) · ΔX is not smaller than the initial value Xs, the controller 70 determines “No” in step S44, and in step S46, instructs the X-direction feed motor control circuit 62 to An instruction is given to move the measurement position by the sensor 10 to the X axis direction negative side. Thereby, the X-direction feed motor control circuit 62 operates the X-direction motor 25 to start moving the measurement position by the magnetic sensor 10 to the X-axis direction negative side.

  Next, the controller 70 inputs the X direction position from the X direction position detection circuit 61 in step S48, and whether or not the X direction position input in step S50 has reached the next measurement position in the X axis direction. That is, it is determined whether or not the value indicating the position in the X direction is equal to or less than the value Xs + (n−2) · ΔX. The controller 70 continues to make a “No” determination in step S50 until the X-direction position input from the X-direction position detection circuit 61 reaches the next measurement position in the X-axis direction, and the processing in steps S48 and S50. Repeatedly. When the X-direction position input from the X-direction position detection circuit 61 reaches the next measurement position in the X-axis direction, the controller 70 determines “Yes” in step S50, and in step S52, the X-direction feed motor control circuit. 62 is instructed to stop the movement of the measurement position by the magnetic sensor 10 to the negative side in the X-axis direction. Thereby, the X-direction feed motor control circuit 62 stops the operation of the X-direction motor 25 and stops the movement of the measurement shooting position by the magnetic sensor 10 to the negative side in the X-axis direction. As a result, the magnetic sensor 10 has the X-axis direction position represented by the value Xs + (n−2) · ΔX (= Xs + (N−2) · ΔX) and the value Ys + (m−1) · ΔYs (= Ys + ΔYs). The magnetic field at the position in the Y-axis direction represented by

  After the process of step S52, the controller 70 returns to step S26, adds the variable a (in this case, a = -1) to the variable n by the process of step S26, and samples the sampling data of the above-described steps S28 and S30. Execute the import process. By the processing in steps S28 and S30, the position in the X-axis direction represented by the value Xs + (n−2) · ΔX (= Xs + (N−2) · ΔX) before the processing in step S26, and the value Ys + ( m−1) · YS (= Ys + ΔYs), each of K sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) is captured and stored. Note that the variable n regarding the sampling data group to be captured and stored is the value N−1, and the variable m is “2”.

  Then, the controller 70 proceeds to steps S26 to S32, S44, and so on until the value Xs + (n−2) · ΔX representing the next measurement position in the X-axis direction (scanning position in the X-axis direction) becomes smaller than the initial value Xs. By the processing of S52, the measurement position is moved to the negative side in the X-axis direction by a predetermined value ΔX, and sampling data is taken in while decreasing the variable n by “1”. Then, when the value Xs + (n−2) · ΔX representing the next measurement in the X-axis direction becomes smaller than the initial value Xs, the controller 70 determines “Yes” in step S44 and performs step S54 in FIG. 6B. Proceed to Note that the variable n at this time is “1”. In this state, the sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) (n = 1, 2, 3... N, m = 1), sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) (n = 1, 2, 3... N, m = 2) is stored in the RAM.

  The controller 70 operates the Y direction motor 34 and moves the measurement position by the magnetic sensor 10 to the next Y-axis direction irradiation position Ys + m · ΔY by the processes of steps S54 to S60 described above. As a result, the magnetic sensor 10 starts to detect the magnetic field at the initial position in the X-axis direction represented by the initial value Xs and at the position in the Y-axis direction represented by the value Ys + m · ΔY (= Ys + 2 · ΔY). Next, on the condition that the Y-direction position detected by the Y-direction position detection circuit 63 does not exceed the end position, the controller 70 determines “No” in step S62, and step S64. In step S66, “1” is added to the variable m, and in step S66, the variable a is multiplied by “−1”. In this case, the variable m becomes “3” by the process of step S64, and the variable a becomes “1” by the process of step S66. The variable n is kept at “1”. After the process of step S66, the controller 70 returns to step S28, and from the processes of steps S28 and S30, the K sampling data groups Sx1 (1, 1) for the lithium ion secondary battery BA specified by the variable s. 3), Sx2 (1,3), Sy1 (1,3), Sy2 (1,3) are taken in from the lock-in amplifier 69 and stored.

  After the processing of steps S28 and S30, the controller 70 determines whether or not the variable a is “1” in step S32. In this case, since the variable a is set to “1” by the process of step S66, the controller 70 determines “Yes” in step S32, and the processes of steps S34 to S42 and S26 to S32 described above. Are repeatedly executed until the value Xs + n · ΔX becomes larger than the end value Xmax. As a result, the measurement position of the magnetic sensor 10 is scanned to the positive side in the X-axis direction, and sampling data groups Sx1 (n, m), Sx2 (n, m), of the lithium ion secondary battery BA specified by the variable s. Sy1 (n, m), Sy2 (n, m) (n = 1, 2, 3... N, m = 3) are newly stored in the RAM.

  When the variable m is set to “3” and the scanning of the measurement position of the magnetic sensor 10 to the positive side in the X-axis direction is completed, the processes of steps S54 to S66 are executed by the determination process of step S34. The measurement position of the magnetic sensor 10 is changed to the next position in the Y-axis direction, and the variables m and a are changed. Then, the measurement position of the magnetic sensor 10 is scanned to the negative side in the X-axis direction by the processes of steps S26 to S32 and S44 to S52 described above, and the sampling data group Sx1 () of the lithium ion secondary battery BA specified by the variable s. n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) (n = 1, 2, 3... N, m = 4) are newly stored in the RAM. .

  Through the processing of steps S26 to S66, the measurement position of the magnetic sensor 10 is scanned so as to reciprocate in the X-axis direction, and is scanned to the Y-axis direction positive side, and is detected by the Y-direction position detection circuit 63. When the position in the Y direction becomes larger than the end value Ymax, the controller 70 determines “Yes” in step S62, and proceeds to step S68. In step S68, the controller 70 determines whether or not there is a lithium ion secondary battery BA that is the next inspection target, that is, whether or not the variable s has reached the number Smax of lithium ion secondary batteries BA. In this case, if the variable s is “1” and the number of lithium ion secondary batteries BA has not been reached, the controller 70 determines “Yes” in step S68 and sets the variable s in step S70. “1” is added, and the process returns to step S14 in FIG. 6A. In this state, the K sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n) for the lithium ion secondary battery BA specified by the variable s (= 1) are stored in the RAM. , m), Sy2 (n, m) (n = 1 to N, m = 1 to M) are stored. The value M is the value of the variable m related to the sampling data group at the measurement position immediately before the end value Ymax, and represents the number of measurement positions in the Y-axis direction.

  In step S14, the controller 70 selects the lithium ion secondary battery BA specified by the variable s, and outputs an instruction signal to the energization selection circuit 67 so as to energize the selected lithium ion secondary battery BA. The energization selection circuit 67 selects the lithium ion secondary battery BA that is energized through the connection L1. Next, the controller 70 initializes the variable n to “0” by the process of step S16 described above, initializes the variables m and a to “1”, respectively, and performs the magnetic sensor by the process of step S18 described above. The ten measurement positions are positioned at the initial positions in the X and Y axis directions represented by the initial values Xs and Ys of the lithium ion secondary battery BA specified by the variable s (= 2). Then, the start of operation of the energization signal supply circuit 65, the energization circuit 66, and the sensor signal extraction circuit 68 is instructed by the processing of steps S20 to S24 described above. However, in this case, since the energization signal supply circuit 65, the energization circuit 66, and the sensor signal extraction circuit 68 are operating, in practice, the energization signal supply circuit 65, the energization circuit 66, and the sensor signal extraction circuit 68 continue to operate. Only.

  After the process of step S24, the controller 70 executes the process of step S26 of FIG. 6A to step S66 of FIG. 6B described above. As a result, the K sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, n) for the lithium ion secondary battery BA specified by the variable s (= 2) are stored in the RAM. m), Sy2 (n, m) (n = 1 to N, m = 1 to M) are stored. Thereafter, the controller 70 determines “Yes” in step S68 until the next lithium ion secondary battery BA to be inspected does not exist, that is, until the variable s reaches the number smax of the lithium ion secondary batteries BA. Then, the process from step S14 in FIG. 6A to step S70 in FIG. 6B is repeatedly executed while increasing the variable s by “1” in step S70. When the variable s reaches the number smax of the lithium ion secondary batteries BA, the controller 70 determines “No” in step S68. Proceed to step S72 and subsequent steps. In this state, K sampling data groups Sx1 (n, m) and Sx2 (n, n) are stored in the RAM for all the lithium ion secondary batteries BA specified by the variable s (1 to smax). m), Sy1 (n, m), Sy2 (n, m) (n = 1 to N, m = 1 to M) are stored.

  The controller 70 instructs the operation stop of the sensor signal extraction circuit 68 in step S72, instructs the operation stop of the energization circuit 66 in step S74, and instructs the operation stop of the energization signal supply circuit 65 in step S76. The operation of the magnetic sensor 10, the energization signal supply circuit 65, the energization circuit 66, the energization selection circuit 67, the sensor signal extraction circuit 68, and the lock-in amplifier 69 is stopped according to these operation stop instructions. After the process of step S76, the controller 70 moves the sensor support base 11 (that is, the magnetic sensor 10) to the X direction drive limit position in step S78, and the X direction position detection circuit 61 and the X direction feed motor control circuit. And instructing the Y-direction position detection circuit 63 and the Y-direction feed motor control circuit 64 to move the sensor support 11 to the Y-direction drive limit position, and executing the data acquisition program in step S80. finish. The X-direction feed motor control circuit 62 moves the sensor support 11 to the X-direction drive limit position in cooperation with the X-direction position detection circuit 61 as in the initial setting described above. As described above, the Y-direction feed motor control circuit 64 moves the sensor support 11 to the Y-direction drive limit position in cooperation with the Y-direction position detection circuit 63.

  Next, a predetermined number K of sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, n) for each lithium ion secondary battery BA specified by the variable s acquired by the data acquisition program. m), Sy2 (n, m) (n = 1 to N, m = 1 to M), a method for evaluating a lithium ion secondary battery will be described. In this case, the operator operates the input device 71 to cause the controller 70 to execute the evaluation programs of FIGS. 7A and 7B. The execution of this evaluation program is started in step S100, and the controller 70 sets the variable s to “1” in step S102. This variable s (= 1 to smax) is the same as that of the data acquisition program described above, and designates each of smax lithium ion secondary batteries BA. Next, after initializing the variables n and m to “1” in step S104, the controller 70 relates to the lithium ion secondary battery BA specified by the variable s in step S106, using the variables n and m. Each of the average values Sx1, Sx2 of the magnitudes of the magnetic fields of the sampling data groups Sx1 (n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) of a predetermined number K specified. , Sy1, Sy2 are calculated. Specifically, for each sampling data group Sx1 (n, m), Sx2 (n, m), Sy1 (n, m), Sy2 (n, m) regarding the lithium ion secondary battery BA specified by the variable s. And K sampling data are added and divided by the value K.

Next, in step S108, the controller 70 performs the following calculations 1 and 2 using the calculated average values Sx1 and Sx2, and thereby the local maximum value Hx of the X direction magnetic detection signal and the X direction magnetic detection signal. The phase shift amount θx with respect to the reference signal is calculated.
Hx = (Sx1 ² + Sx2 ² ) ^1/2 Formula 1
θx = tan ^-1 (Sx2 / Sx1) ... Formula 2
As a result, Hx · sin (2πft + θx) is detected as the X-direction magnetic detection signal. Note that f is equal to the frequency of the energization signal and the reference signal output from the energization signal supply circuit 65.

Next, in step S110, the controller 70 performs the calculations of the following equations 3 and 4 using the calculated average values Sy1 and Sy2, and thereby the maximum value Hy of the Y-direction magnetic detection signal and the Y-direction magnetic detection signal. The phase shift amount θy with respect to the reference signal is calculated.
Hy = (Sy1 ² + Sy2 ² ) ^1/2 Formula 3
θy = tan ^-1 (Sy2 / Sy1) ... Equation 4
As a result, Hy · sin (2πft + θy) is detected as the Y-direction magnetic detection signal.

Next, in step S112, the controller 70 executes the following Equations 5 and 6 using the calculated Hx, θx, Hy, and θy, and thereby the timing at which the energization current amount becomes maximum (the X-direction magnetic detection). The magnetic field strength Hxy and the magnetic field direction θxy at the inspection position at the signal Hx · sin (2πft + θx) and the 2πft in the Y-direction magnetic detection signal Hy · sin (2πft + θy) are π / 2 are calculated. In this case, the reason why the timing at which the energization current amount is maximum is adopted is that the phase shift amounts θx and θy are small, and the magnetic field strength Hxy at the inspection position is a value near the maximum value in the vicinity of the timing at which the energization current amount is maximum. Because it becomes. When the phase shift amounts θx and θy are not small and the magnetic field strength Hxy at the inspection position does not become close to the maximum value near the timing when the energization current amount becomes maximum, the magnetic field strength Hxy is close to the maximum value. The timing angle may be used instead of π / 2.
Hxy = [{Hx · sin (π / 2 + θx)} ² + {Hy · sin (π / 2 + θy)} ² ] ^1/2
θxy = tan ⁻¹ {Hy · sin (π / 2 + θy)} / {Hx · sin (π / 2 + θx)} Equation 6

Next, in step S114, the controller 70 determines that the current flowing through each part in the lithium ion secondary battery BA is proportional to the magnetic field strength Hxy and the direction is different from the magnetic field direction θxy by −π / 2. The magnitude Ixy and the direction θixy of the current flowing at the inspection position of the lithium ion secondary battery BA at the timing when the amount of energization current becomes maximum by executing the calculations of the following formulas 7 and 8 using the calculated Hxy and θxy. Calculate However, the value K is a proportionality constant.
Ixy = K · Hxy Equation 7
θixy = θixy−π / 2 Equation 8

  In step S114, the calculated current magnitude Ixy and direction θixy are data relating to the lithium ion secondary battery BA specified by the variable s, and the inspection position of the lithium ion secondary battery BA is determined. Using the variables n and m to represent, the current magnitude data Ixy (n, m) and the current direction data θixy (n, m) are stored in the RAM or the storage device.

Next, in step S116, the controller 70 executes currents flowing in the X direction and the Y direction at the inspection position of the lithium ion secondary battery BA by executing the calculations of the following formulas 9 and 10 using the calculated Ixy and θixy. The magnitudes Ix and Iy are calculated.
Ix = Ixy · cosθixy (Equation 9)
Iy = Ixy · sinθixy (Formula 10)
In step S116, the calculated current magnitudes Ix and Iy are also data related to the lithium ion secondary battery BA specified by the variable s and represent the inspection position of the lithium ion secondary battery BA. Using the variables n and m, current magnitude data Ix (n, m) and Iy (n, m) in the X and Y directions are stored in the RAM or storage device.

  After the process of step S116, the controller 70 adds “1” to the variable n in step S118, and determines in step S120 whether or not the variable n is larger than a value N representing the number of detected positions in the X-axis direction. To do. If the variable n is less than or equal to the value N, the controller 70 determines “No” in step S120, returns to step S106, and repeatedly executes the processes of steps S106 to S120 described above. If the variable n becomes larger than the value N during the repetitive processing in steps S106 to S120, the controller 70 determines “Yes” in step S120 and defines the inspection position in the Y-axis direction in step S122. In step S124, it is determined whether or not the variable m is larger than a value M representing the number of detected positions in the Y-axis direction. If the variable m is equal to or less than the value M, the controller 70 determines “No” in step S124, returns the variable n to the initial value “1” in step S126, and then performs steps S106 to S126 described above. Repeat the process. If the variable m becomes larger than the value M during the repetition processing of steps S106 to S126, the controller 70 determines “Yes” in step S124 and proceeds to step S130 in FIG. 7B.

  At this time, current magnitude data Ixy (n, m), current direction data θixy (n, m), and current magnitude data in the X direction for each inspection position of the lithium ion secondary battery BA specified by the variable s. Ix (n, m) and Y-direction current magnitude data Iy (n, m) (n = 1 to N, m = 1 to M) are stored in the RAM or the storage device.

  The processing of steps S130 to S156 in FIG. 7B uses the Y-direction current magnitude data Iy (n, m) (n = 1 to N, m = 1 to M), and the electrodes of each lithium ion secondary battery BA. This is a process for detecting the position. In step S130, the controller 70 initializes a variable ep for specifying an electrode to “1”. Next, in step S132, the controller 70 first uses the current magnitude data Iy (n, m) (n = 1 to N, m = 1 to M) in all Y directions to calculate the current in the Y direction. Find frequency distribution with respect to size. For example, as shown in FIG. 11, the frequency distribution is a distribution in which a small current portion and a large current portion are clearly distinguished. This is based on the fact that a large current flows in the extending direction of the electrode at the electrode position (electrode region), and no large current flows in the extending direction of the electrode in the electrolyte region. In step S132, the controller 70 derives the maximum value of the current magnitude based on the frequency distribution, and derives the magnitude of the current having the maximum frequency (hereinafter referred to as a maximum value). From the current magnitude data Iy (n, m) in all Y directions, current magnitude data greater than or equal to the maximum value−2 × (maximum value−maximum value) (see FIG. 11) is extracted to obtain candidate electrode positions. The current magnitude data Iy (n, m) is stored in a RAM or a storage device.

  Next, in step S134, the controller 70 classifies the extracted electrode position candidate current magnitude data Iy (n, m) for each variable n, and the variable n is the same and has the maximum number. The size data Iy (n, m) is extracted and separated, and the number of separation and extraction is stored in the RAM or storage device as the number of extraction Ny (ep), and the current magnitude data group that has been separated and extracted is newly electroded. The current magnitude data Iy (n, m, ep) of the position is stored in the RAM or the storage device. By the extraction / separation process, the current magnitude data Iy of the electrode position newly stored from the current magnitude data Iy (n, m) of the electrode position candidate stored in the RAM or the storage device by the process of step S132. The current magnitude data Iy (n, m) corresponding to (n, m, ep) is removed (erased).

  Next, in step S136, the controller 70 determines whether the extraction number Ny (ep) is equal to or greater than the predetermined number Ny0. The predetermined number Ny0 is a determination value of the electrode length in the Y direction. For example, the input value in the Y direction of the lithium ion secondary battery and a minute value ΔY indicating a predetermined detection interval in the Y direction are obtained. The value calculated by using (Y-direction length / ΔY) / 3. First, the case where the electrode is extended in the Y direction and the extraction number Ny (ep) is equal to or greater than the predetermined number Ny0 will be described. In this case, the controller 70 determines “Yes” in step S136, and executes the processing after step S150. In this state, one electrode extending in the Y direction of the designated lithium ion secondary battery is detected, and current magnitude data Iy (n, m, ep) (ep = 1) is detected. It is stored in RAM or a storage device as data representing the electrode position.

  In step S150, the controller 70 adds “1” to the variable ep. In step S152, the controller 70 determines whether or not the added variable ep is greater than the number of input electrodes of the designated lithium ion secondary battery. If the variable ep is still less than or equal to the number of electrodes, the controller 70 determines “No” in step S152 and proceeds to step S154.

  In step S154, the controller 70 obtains the electrode position candidate current magnitude data Iy (n, m) extracted by the process of step S132, and the electrode position current magnitude data Iy of the step S134. From the remaining current magnitude data Iy (n, m) from which (n, m, ep) is extracted and separated and stored in the RAM or storage device, the current magnitude data Iy (n , M, ep) exclude (ie, erase) current magnitude data Iy (n, m) at positions on both sides in the X direction of the position defined by variable n and where the X direction position specified by variable n is less than a predetermined number K. ) To extract current magnitude data Iy (n, m) of a new electrode position candidate. The predetermined number K is a determination value of the length between the electrodes in the X direction. For example, the input X direction length of the lithium ion secondary battery and a minute value ΔX indicating a predetermined detection interval in the X direction. The value calculated by using (length in the X direction / ΔX) / 5. By the process of step S154, other electrodes are not erroneously detected by the next detection process near the side of the electrode position determined by the process of step S134.

  Next, in step S156, the controller 70 classifies the current magnitude data Iy (n, m) of the electrode position candidate newly extracted by the process of step S154 for each variable n, and the variable n is the same. The current magnitude data Iy (n, m) having the largest number is extracted and separated, and the separated and extracted number is stored in the RAM or the storage device as the extracted number Ny (ep), and the separated and extracted current is stored. The magnitude data group is stored in the RAM or storage device as the current magnitude data Iy (n, m, ep) of the new electrode position. Also in this extraction / separation process, the current magnitude of the extracted electrode position is extracted from the current magnitude data Iy (n, m) of the electrode position candidate extracted by the process of step S154 and stored in the RAM or the storage device. The current magnitude data Iy (n, m) corresponding to the data Iy (n, m, ep) is removed (erased).

  After the process of step S156, the controller 70 again determines in step S136 whether the extraction number Ny (ep) is equal to or greater than the predetermined number Ny0. Also in this case, if the extraction number Ny (ep) is equal to or greater than the predetermined number Ny0, the controller 70 determines “Yes” in step S136, and executes the processes in and after step S150. In this state, the second electrode extending in the Y direction of the designated lithium ion secondary battery is detected, and current magnitude data Iy (n, m, ep) (ep = 2) Is stored in the RAM or storage device as data representing the second electrode position. Then, until the variable ep indicating the number of electrodes increased by the process of step S150 becomes larger than the input number of electrodes, it is determined as “No” in step S152, and the controller 70 performs the steps S150 to S156, S136. By executing the process, the electrode position extended in the Y direction is detected, and the current magnitude data Iy (n, m, ep) of the detected electrode position is stored in the RAM or the storage device. On the other hand, if the variable ep indicating the number of electrodes increased by the process of step S150 is larger than the input number of electrodes, the controller 70 determines “Yes” in step S152 and performs step S160 of FIG. 7C. Proceed to

  Next, the case where the electrode is extended in the X direction will be described. In this case, the extraction number Ny (ep) set by the process of step S134 is smaller than the predetermined number Ny0 because the electrode extends in the X direction, and the controller 70 performs the process after the process of step S134. In step S136, it is determined as “No”, and the process proceeds to step S138. In step S138, the controller 70 determines whether or not the variable ep indicating the number of electrodes is “1”. In this case, since the electrode extends in the X direction and the position of the electrode extended in the Y direction is not detected, the variable ep is still “1”, and the controller 70 determines “Yes in step S138. And proceeds to step S140.

  In step S140, the controller 70 obtains a frequency distribution with respect to the current magnitudes of all the current magnitude data Ix (n, m) (n = 1 to N, m = 1 to M) in the X direction. Also in this case, the frequency distribution is as shown in FIG. 11, for example. Then, in step S140, the controller 70 derives the maximum value of the current magnitude based on the frequency distribution in the same manner as in the process of step S132, and the current magnitude (hereinafter referred to as the maximum) having the maximum frequency. Electrode) by extracting current magnitude data of maximum value-2 x (maximum value-maximum value) or more from all current magnitude data Iy (n, m) in the X direction. Candidate current magnitude data Ix (n, m) is stored in a RAM or storage device.

  Next, in step S142, the controller 70 erases the electrode position data Iy (n, m, ep) stored in the RAM or the storage device by the process of step S134, and the electrode position extracted by the process of step S140. The candidate current magnitude data Ix (n, m) is classified for each variable m, and the current magnitude data Ix (n, m) having the same variable m and the largest number is extracted and separated. The separated and extracted number is stored in the RAM or storage device as the extracted number Nx (ep), and the separated or extracted current magnitude data group is stored as the electrode position current magnitude data Ix (n, m, ep) in the RAM or storage device. To remember. In this case as well, by the extraction / separation process, the electrode position candidate current magnitude data Ix (n, m) stored in the RAM or the storage device by the process of step S140 is used to determine the newly stored electrode position. The current magnitude data Ix (n, m) corresponding to the current magnitude data Ix (n, m, ep) is removed (erased).

  Next, in step S144, the controller 70 determines whether the extraction number Nx (ep) is equal to or greater than the predetermined number Nx0. The predetermined number Nx0 is a determination value of the electrode length in the X direction. For example, the input X direction length of the lithium ion secondary battery and a minute value ΔX indicating a predetermined detection interval in the X direction are used. (X-direction length / ΔX) / 3. In this case, since the electrode extends in the X direction and the extraction number Nx (ep) is equal to or greater than the predetermined number Nx0, the controller 70 determines “Yes” in step S144, and performs the processing in steps S146 and S148. Execute. In this state, one electrode extending in the X direction of the designated lithium ion secondary battery is detected, and current magnitude data Ix (n, m, ep) (ep = 1) is detected. It is stored in RAM or a storage device as data representing the electrode position.

  In step S146, all current magnitude data Ixy (n, m), current direction data θixy (n, m), X-direction current magnitude data Ix (n, m), and Y-direction current magnitude data Iy. (n, m), the extracted number Nx (ep), and the current magnitude data Ix (n, m, ep) of the electrode position are replaced with the current magnitude data Ixy ( m, n), current direction data θixy (m, n), current magnitude data Ix (m, n) in the X direction, current magnitude data Iy (m, n) in the Y direction, extraction number Nx (ep) and It is converted into current magnitude data Ix (m, n, ep) at the electrode position. That is, this conversion is performed for all current magnitude data Ixy (n, m), current direction data θixy (n, m), current magnitude data Ix (n, m) in the X direction, current magnitude data in the Y direction. The distribution in the XY coordinates of Iy (n, m), the number of extractions Nx (ep) and the current magnitude data Ix (n, m, ep) of the electrode position is divided into two equal parts passing through the origins of the X axis and the Y axis. It means to move symmetrically around the line. The reason for performing this conversion is to detect the electrode extending in the X direction by the processing in steps S154, S156, and S136 described above (detection processing of the electrode extending in the Y direction). In step S148, the variable CH representing the conversion in step S146 is set to “1”. The variable CH is initially set to “0”.

  After the process of step S148, the controller 70 detects the electrode extended in the X direction while increasing the variable ep indicating the number of electrodes by “1” by the process of steps S150 to S156 and S136 described above. The Y direction current magnitude data Iy (n, m) of the detected electrode position is stored in the RAM or the storage device as the current magnitude data Iy (n, m, ep) of the electrode position. Then, until the variable ep indicating the number of electrodes increased by the process of step S150 becomes larger than the input number of electrodes, it is determined as “No” in step S152, and the controller 70 performs the steps S150 to S156, S136. By executing this process, the electrode position extended in the X direction is detected, and the current magnitude data Iy (n, m, ep) of the detected electrode position is sequentially stored in the RAM or the storage device. On the other hand, if the variable ep indicating the number of electrodes increased by the process of step S150 is larger than the input number of electrodes, the controller 70 determines “Yes” in step S152 and performs step S160 of FIG. 7C. Proceed to

  Next, the case where the electrode of the lithium ion secondary battery BA is not detected will be described. As an example of the case where this electrode is not detected, an electrode having a predetermined length is extended in the same direction as the first detected direction when no electrode is detected in either the X direction or the Y direction. There are cases where electrodes are not detected for the number of input electrodes. In the former case, since the variable ep representing the number of electrodes is set to “1” by the process of step S130, the controller 70 determines “No” in step S136, that is, the number of extractions Ny (ep) by step S134. It is determined that the number is less than the predetermined number Ny0 and “No” in step S144 after the determination of “Yes” (ep = 1) in step S138, that is, the number Nx (ep) extracted in step S142 is less than the predetermined number Nx0. It is determined that there is, and the process proceeds to step S226 in FIG. 7E. In the latter case, the variable ep is processed in step S150 by detecting the electrode extended in the Y direction by the processes in steps S132 to S136 or detecting the electrode extended in the X direction by the processes in steps S140 to S144. Therefore, the controller 70 determines that “No” in step S136, that is, the number Ny (ep) extracted in step S134 is less than the predetermined number Ny0, and the process returns to step S138. If “No”, that is, the variable ep is not “1”, the process proceeds to step S226 in FIG. 7E.

  Next, processing in steps S160 to S186 in FIG. 7C will be described. The processing of steps S160 to S186 is performed by the electrode position current magnitude data Iy (n, m, ep) extracted for each electrode (ep = 1, 2,...) By the processing of steps S130 to S156 of FIG. Is used to newly set the current magnitude data Iy (n, m, ep) of the electrode area, and the electrode area EP1 using the newly set current magnitude data Iy (n, m, ep) of the electrode area. , EP2... That is, the current magnitude data Iy (n, m, ep) corresponding to the width of the electrode (width in the X and Y directions) is added to the current magnitude data Iy (n, m, ep) at the electrode position. Region current magnitude data Iy (n, m, ep) is set, and as shown in FIG. 12, two X, Y defined by the current magnitude data Iy (n, m, ep) of the electrode region are set. The electrode regions EP1, EP2,... Surrounded by the coordinate values (Nmi (ep), Mmi (ep)), (Nma (ep), Mma (ep)) are detected. In FIG. 12, a square by the outermost solid line indicates a magnetic field detection region, and a square by the inner broken line indicates an outer frame of the lithium ion secondary battery BA.

  In this electrode region detection process, the controller 70 first initializes a variable ep representing an electrode to “1” in step S160. Next, in step S162, the controller 70 selects electrodes (variables) from all the detected Y-direction current magnitude data Iy (n, m) (n = 1 to N, m = 1 to M). ep), the X, Y coordinate value periphery of the electrode position defined by the current magnitude data Iy (n, m, ep) of the electrode position determined by the processing of steps S130 to S156, that is, the electrode position is determined. The current magnitude data Iy (na, mb, ep) to Iy (n + a, m + b, ep) around the included electrode position are extracted, and the extracted current magnitude data Iy (na, mb) , Ep) to Iy (n + a, m + b, ep) are stored in the RAM or the storage device as current magnitude data Iy (n, m, ep) of the electrode region candidates. In this case, the values a and b are sufficiently large values that are determined in advance and surround the electrode region. For example, the value a is a value calculated using the input X-direction length of the lithium ion secondary battery and a minute value ΔX indicating a predetermined detection interval in the X direction (X-direction length × 0. 2) / ΔX. The value b is a value calculated using the input Y-direction length of the lithium ion secondary battery and a minute value ΔY indicating a predetermined detection interval in the Y-direction (Y-direction length × 0. 2) / ΔY). Note that the current magnitude data Iy (n, m, ep) at the electrode position described above is included in the current magnitude data Iy (n, m, ep) of the electrode region candidate and is substantially erased.

  After the process of step S162, the controller 70, in step S164, the current magnitude data Iy (n, m) of the extracted electrode region candidate having the same variable m that defines the position in the Y direction (electrode extending direction). , Ep) average value AveIy (m, ep) is calculated for each variable m. In other words, average values AveIy (m, ep) of the current magnitude data Iy (n, m, ep) of the electrode region candidates are calculated along the Y direction. In step S166, the maximum value is extracted from all the calculated average values AveIy (m, ep) and set as the maximum value MaxIym (ep). Next, in step S168, the controller 70 multiplies the extracted maximum value MaxIym (ep) by a predetermined set ratio from the calculated average values AveIy (m, ep) (MaxIym ( The average value AveIy (m, ep) is extracted. In this case, the set ratio is a predetermined value for calculating the minimum value of the magnitude of the current flowing in the Y direction in the Y direction of the electrode, and is 0.05, for example.

  After the process of step S168, the controller 70 sets the maximum value of the variable m in the average value AveIy (m, ep) extracted by the process of step S168 as the Y-direction maximum value Mma (ep) in step S170. In step S172, the minimum value of the variable m in the average value AveIy (m, ep) extracted by the process in step S168 is set as the Y-direction minimum value Mmi (ep). Thereby, as shown in FIG. 12, both ends in the Y direction of the electrode specified by the variable ep are specified as the Y direction maximum value Mma (ep) and the Y direction minimum value Mmi (ep).

  After the processing of step S172, the controller 70, in step S174, calculates the average value of the current magnitude data Iy (n, m, ep) of the extracted electrode region candidates having the same variable n that defines the position in the X direction. AveIy (n, ep) is calculated for each variable n. In other words, average values AveIy (n, ep) of the current magnitude data Iy (n, m, ep) of the electrode region candidates are calculated along the X direction. In step S176, the maximum value is extracted from all the calculated average values AveIy (n, ep) and set as the maximum value MaxIyn (ep). Next, in step S178, the controller 70 multiplies the extracted maximum value MaxIyn (ep) by a predetermined setting ratio (MaxIyn (ep) from all the calculated average values AveIx (n, ep). ep) × setting ratio) The average value AveIy (n, ep) above is extracted. In this case, the set ratio is a predetermined value for calculating the minimum value of the magnitude of the current flowing in the Y direction in the X direction of the electrode, for example, 0.05.

  After the process of step S178, the controller 70 sets the maximum value of the variable n in the average value AveIy (n, ep) extracted by the process of step S178 as the maximum value in the X direction Nma (ep) in step S180. In step S182, the minimum value of the variable n in the average value AveIy (m, ep) extracted by the process in step S178 is set as the X direction minimum value Mmi (ep). Thereby, as shown in FIG. 12, both ends in the X direction of the electrode specified by the variable ep are specified as the X direction maximum value Nma (ep) and the X direction minimum value Nmi (ep). As a result, the electrode region specified by the variable ep (= 1) has four X and Y coordinate values (Nmi (1), Mmi (1)), (Nmi (1), Mma (1)), (Nma (1), Mmi (1)), (Nma (1), Mma (1)) is determined as an area EP1.

  After the process of step S182, the controller 70 adds “1” to the variable ep representing the electrode in step S184, and the variable ep exceeds the number of electrodes of the input lithium ion secondary battery BA in step S186. Determine whether or not. If the variable ep does not exceed the input number of electrodes, the controller 70 determines “No” in step S186 and returns to step S162. Then, by the processing consisting of steps S162 to S182 described above, four X and Y coordinate values (Nmi (2), Mmi (2) defining the region EP2 of the electrode specified by the variable ep (= 2), that is, the region EP2. )), (Nmi (2), Mma (2)), (Nma (2), Mmi (2)), (Nma (2), Mma (2)) are detected.

  In this way, the electrode regions EP1 and EP2 of the lithium ion secondary battery BA are sequentially detected. Further, if there is an electrode, that is, if the variable ep does not exceed the input number of electrodes, the controller 70 again determines “No” in step S186 and detects the region of the next electrode. Steps S162 to S182 are executed. On the other hand, that is, when the variable ep exceeds the input number of electrodes, the controller 70 determines “Yes” in step S186 and proceeds to step S190 in FIG. 7D.

  Next, the processing in steps S190 to S204 in FIG. 7D will be described. The processes in steps S190 to S204 are processes for detecting an electrolyte region ER in which a current flows in the lithium ion secondary battery BA as shown in FIG. In this electrolyte region detection process, first, in step S190, the controller 70 sets all the current magnitude data Ix (n, m) (n = 1 to N) in the X direction detected by the process of step S116. , M = 1 to M), the current magnitude data Ix (n, m) in the X direction excluding the current magnitude data Ix (n, m) in the X direction of the electrode region is extracted, The extracted X-direction current magnitude data Ix (n, m) group is stored in the RAM or storage device as the electrolyte region candidate current magnitude data Ix1 (n, m) group. In this case, since the main direction of the current flowing through the electrolyte region is the X direction including the X coordinate and the Y coordinate converted by the process of step S146 of FIG. 7B, the current magnitude data Ix in the X direction (n, m) is adopted. In addition, the current magnitude data Ix (n, m) in the X direction of the excluded electrode region includes four X, Y representing the regions of all the electrodes detected by the processes in steps S160 to S186 in FIG. 7C. Coordinate values (Nmi (ep), Mmi (ep)), (Nmi (ep), Mma (ep)), (Nma (ep), Mmi (ep)), (Nma (ep), Mma (ep)) ( ip = 1, 2,...)

After the processing of step S190, the controller 70, in step S192, the current magnitude data Ix1 (n, m) of the extracted electrolyte region candidate having the same variable m that defines the position in the Y direction (electrode extending direction). ) Average value AveIx (m) is calculated for each variable m. In other words, the average value AveIy (m) of the current magnitude data Ix1 (n, m) of the electrolyte region candidate is calculated along the Y direction. In step S194, the rate of change SL (m) of the average value AveIy (m) is calculated by executing the calculation of the following equation 11 while changing the variable m from “1” to “M−1”. .
SL (m) = | AveIx (m) −AveIx (m + 1) | / {AveIx (m) + AveIx (m + 1)}
(M = 1 to M−1) Equation 11
The rate of change SL (m) represents the rate of change of adjacent current magnitude data Ix1 (n, m) in the Y direction (electrode extending direction).

  Next, in step S196, the controller 70 detects and detects the variable m having the maximum change rate SL (m) in the Y-direction region where the variable m is between “1” and “M / 4”. Let the value of the variable m be the minimum value Mmin in the Y direction. In step S198, the variable m having the maximum change rate SL (m) is detected in the Y-direction region where the variable m is between “3 · M / 4” and “M−1”. Let the value of m be the maximum value Mmax in the Y direction. These minimum value Mmin in the Y direction and maximum value Mmax in the Y direction are values that define the lower limit and the upper limit in the Y direction of the electrolyte region through which the current flows. In the detection of the boundary (lower limit and upper limit) of the electrolyte region through which the current flows through the processing of these steps S196 and 198, the current magnitude data Ix1 (n, m) changes extremely at the boundary of the electrolyte region. Based on that. In the process of step S196, the reason why the variable m is limited to the Y-direction region between “1” and “M / 4” is that the lower limit of the electrolyte region through which the current flows is at least the variable m from “1” to “M This is because it exists at a position in the Y direction between “/ 4”. In the process of step S198, the variable m is limited to the Y direction region between “3 · M / 4” and “M−1” because the upper limit of the electrolyte region through which the current flows is at least “3”. It is because it exists in the Y direction position between “M / 4” and “M−1”.

  After the process in step S198, the controller 70 determines in step S200 that the minimum value among the X direction minimum values Nmi (ep) (ep = 1 to the number of electrodes) for all the electrodes by the process in step S182 of FIG. X direction minimum value Nmi (ep) is detected, and the detected X direction minimum value Nmi (ep) is set as the X direction minimum value Nmin. Next, in step S202, the controller 70 determines the maximum X-direction maximum among the X-direction maximum values Nma (ep) (ep = 1 to the number of electrodes) related to all electrodes by the process of step S180 of FIG. 7C. The value Nma (ep) is detected, and the detected X direction maximum value Nma (ep) is set as the X direction maximum value Nmax. These X direction minimum value Nmin and X direction maximum value Nmax represent both outer ends of the pair of electrodes located on the outermost side in the X direction of the lithium ion secondary battery BA.

  After the processing in step S202, the controller 70 in step S204, the region surrounded by the X direction minimum value Nmin, the X direction maximum value Nmax, the Y direction minimum value Mmin, and the Y direction maximum value Mmax, that is, the X direction in the X direction. A region that is sandwiched between the minimum value Nmin and the maximum value Nmax in the X direction, and that excludes the electrode regions EP1, EP2,... From the region sandwiched between the minimum value Mmin in the Y direction and the maximum value Mmax in the Y direction in the Y direction. An XY coordinate group representing the ER, that is, the electrolyte region is defined as an electrolyte coordinate group B (n, m) (see FIG. 12). The electrode regions EP1, EP2,... Are the X direction minimum value Mmi (ep) and the X direction maximum value Nma related to the electrodes (ep = 1 to the number of electrodes) obtained by the processing in steps S170, S172, S180, and S182 of FIG. (ep), the region surrounded by the minimum value Mmi (ep) in the Y direction and the maximum value Mma (ep) in the Y direction, that is, sandwiched between the minimum value Mmi (ep) in the X direction and the maximum value Nma (ep) in the X direction. And a region sandwiched between the Y direction minimum value Mmi (ep) and the Y direction maximum value Mma (ep) in the Y direction. In this case, the variable n represents the coordinate position of each detection position of the magnetic field in the X direction, and the variable m represents the coordinate position of each detection position in the Y direction.

After the process of step S204, the controller 70 executes the processes of steps S210 to S222 in FIG. 7E. The processes in steps S210 to S222 are processes for evaluating the performance of the lithium ion secondary battery BA based on the distribution of the magnitude of the current flowing through the electrolyte region ER. FIG. 13 shows a distribution state of current magnitude data Ixy (n, m) flowing through the electrolyte region ER. First, in step S210, the controller 70 uses the current magnitude data Ixy (n, m) detected and stored by the process of step S114 of FIG. 7A to determine the current magnitude data Ixy (in the determined electrolyte region). n, m), that is, the maximum value of the current magnitude data Ixy (n, m) at the XY coordinate position defined by the electrolyte coordinate group B (n, m) is detected, and the detected maximum value is determined as the current. Set as the maximum value MaxIxy. Next, in step S212, the controller 70 calculates the following equation 12 for all current magnitude data Ixy (n, m) at the XY coordinate positions defined by the electrolyte coordinate group B (n, m). The current magnitude ratio Irxy (n, m) is calculated by executing the above calculation.
Irxy (n, m) = Ixy (n, m) / MaxIxy Equation 12

Next, in step S214, the controller 70 initializes the current magnitude ratio p to a predetermined minute value Δra. In step S216, among the calculated current magnitude ratio Irxy (n, m), the number of current magnitude ratios Irxy (n, m) greater than or equal to the current magnitude ratio p is detected, and the detected number. Is divided by the number of electrolyte coordinate groups B (n, m) (that is, the number of all current magnitude ratios Irxy (n, m)). The ratio occupied by the magnitude ratio Irxy (n, m) is calculated and stored in the RAM or the storage device as the current magnitude ratio ratio Rate (p).
Rate (p) = number of Irxy (n, m) greater than or equal to p / number of B (n, m) Equation 13
Next, the controller 70 determines whether or not the current magnitude ratio p is “1” or more in step S218. In this case, since the current magnitude ratio p is equal to the minute value Δra, the controller 70 determines “No” in step S218, and adds the minute value Δra to the current magnitude ratio p in step S220. The processing of S216 and S218 is executed again.

Through the processing in steps S216 to S220, the current magnitude ratio Rate (p) is sequentially calculated while increasing the current magnitude ratio p by a minute value Δra. When the current magnitude ratio p becomes “1” or more, the controller 70 determines “Yes” in step S218, and sets each current magnitude ratio Irxy (n, m) in step S222. The following formula 14 is used to multiply and add the ratio (number of 1 / B (n, m)) that the current magnitude ratio Irxy (n, m) occupies with respect to all the current magnitude ratios Irxy (n, m). The area value Area is calculated by executing the calculation.
Area = ΣIrxy (n, m) / number of B (n, m) Equation 14
Next, in step S224, the controller 70 creates a graph representing a change in the current magnitude ratio Rate (p) with respect to the intensity ratio 0 to 1, and displays the created graph on the display device 72. Further, the controller 70 also displays the calculated area value Area in the step S224.

  Here, a graph representing a change in the current magnitude ratio Rate (p) with respect to the current magnitude ratio p (= 0 to 1) and the area value Area will be described. Changes in the current magnitude ratio Rate (p) with respect to the current magnitude ratio p (= 0 to 1), that is, the current magnitude ratio p (= 0 to 1) and the current magnitude ratio ratio greater than the current magnitude ratio p. The relationship curve with Rate (p) is as shown in FIG. The ratio of the current magnitude ratio Irxy (n, m) exceeding “1” is “0”, and the ratio of the current magnitude ratio Irxy (n, m) greater than “0” is “1”. Therefore, every relational curve becomes a curve connecting (0, 1) and (1, 0) in the X and Y coordinates. When the ratio of the large current is larger than the ratio of the small current, the relation curve becomes a solid line indicated by A. On the other hand, when the ratio of the small current is larger than the ratio of the large current, the relation curve becomes a broken line shown in B. If all the currents are uniform, the relationship curve looks like a rectangle indicated by a two-dot chain line. And it shows that the performance of the lithium ion secondary battery BA including the degree of deterioration tends to become worse as the distance from the rectangle indicated by the two-dot chain line increases, that is, as the relationship curve becomes a broken line B through the solid line A.

  Next, the area value Area will be described. The area surrounded by the relationship curve and the X and Y axes in FIG. 14 is such that the smaller the current ratio, the greater the current ratio, that is, the worse the performance of the lithium ion secondary battery BA including the degree of deterioration. , Get smaller. In addition, calculation of this area means calculating the integral value of the function which prescribes | regulates the relationship curve in this invention. That is, if all currents are uniform, the area is “1”. Then, the performance of the lithium ion secondary battery BA including the degree of deterioration is not good, that is, the ratio of the small current to the ratio of the large current becomes large, and the relation curve becomes a relation curve by the broken line B through the solid line A. The area becomes smaller. That is, the smaller the area, the less the performance of the lithium ion secondary battery BA.

  On the other hand, this area is equal to the area value Area calculated by Equation (13). FIG. 15 shows a relational curve indicated by a solid line A in FIG. 14. The minute width in the Y-axis direction corresponding to the current magnitude ratio p is equal to the ratio occupied by the current magnitude ratio Irxy (n, m). It is. The calculation of the equation 13 is an operation of adding the multiplication result of the current magnitude ratio Irxy (n, m) and the ratio thereof. In other words, the calculation of the area value Area of the equation 13 is shown in FIGS. It is equal to the calculation result obtained by integrating the relationship curve in the Y-axis direction. Therefore, the area value Area based on the calculation result of Expression 13 is equal to the area surrounded by the relational curve in FIG. 14 and the X and Y axes. The performance of the lithium ion secondary battery BA can be evaluated depending on how far it is from “1”.

  After the process of step S224, the controller 70 proceeds to step S228. On the other hand, as described above, when the electrode of the lithium ion secondary battery BA is not detected and it is determined “No” in steps S138 and S144 of FIG. 7B, the process proceeds to step S226 of FIG. 7E. In step S226, the controller 70 displays on the display device 72 that the evaluation is impossible, that is, it is impossible to evaluate the degree of uniformity of the current in each part of the electrolyte region, and the process proceeds to step S228. . In this case, the operator may determine the reason why the evaluation cannot be performed by looking at a current distribution image to be described later, set the electrolyte region while viewing the screen, and perform the same processing as the processing by the program. In addition, for example, processing such as re-measurement by changing the placement of the lithium ion secondary battery BA, or re-measurement by changing the setting when extracting the electrolyte region may be performed.

  In step S228, it is determined whether or not the variable CH is “1”, that is, whether or not the conversion processing of the X and Y coordinate values in step S146 of FIG. 7B described above has been performed. If the variable CH is “0” and the X and Y coordinate values are not converted, the controller 70 determines “No” in step S228 and proceeds to step S232. On the other hand, if the variable CH is “1” and the conversion processing of the X and Y coordinate values has been performed, the controller 70 determines “Yes” in step S228 and proceeds to step S230. In step S230, all current magnitude data Ixy (n, m), current direction data θixy (n, m), current magnitude data Ix (n, m) in the X direction, and current magnitude data Iy in the Y direction. By replacing (n, m) with their X coordinate value and Y coordinate value, current magnitude data Ixy (m, n), current direction data θixy (m, n), current magnitude data Ix in the X direction (m, n) and Y-direction current magnitude data Iy (m, n). Then, the process proceeds to step S232. That is, the conversion processing of the X and Y coordinate values in step S146 of FIG.

  In step S232, the controller 70 determines the current magnitude data Ixy (n, m) and direction data θixy (n, m) (n = 1 to N, m = 1 to M), and the X direction and the Y direction. The display image data is generated from the magnitude data Ix (n, m), Iy (n, m) (n = 1 to N, m = 1 to M) of the current flowing through the image, and the image is represented by the image data. Is displayed on the display device 72 together with a display for specifying the lithium ion secondary battery BA specified by the variable s. In this image, for example, the length of the arrow varies depending on the current magnitude data Ixy (n, m) for each inspection position of the lithium ion secondary battery BA, and the current direction data θixy (n, m) It is better to display the arrows in different directions. In addition, a display that changes the brightness, color, etc. of the inspection position according to the current magnitude data Ixy (n, m) may be included. Further, regarding the magnitude data Ix (n, m) and Iy (n, m) of the current flowing in the X direction and the Y direction, the current magnitude data Ixy (n, m) and the direction data θixy (n, m) ) May be used, but in this case, since the direction of the current is constant, the brightness, color, etc. of the inspection position are represented by current magnitude data Ix (n, m), Iy (n, It may be different depending on m).

  Next, the controller 70 determines whether or not there is an instruction to evaluate the next lithium ion secondary battery BA in step S234. In this case, if the operator does not instruct switching to the next lithium ion secondary battery BA, the controller 70 continues to determine “No” in step S234 and repeatedly executes the determination process in step S234. On the other hand, when the operator uses the input device 71 to instruct switching to the next lithium ion secondary battery BA, the controller 70 determines “Yes” in step S234 and proceeds to step S236. In step S236, the controller 70 determines whether or not the variable s has reached the number smax of the lithium ion secondary batteries BA. If the variable s has not yet reached the number smax, the controller 70 determines “No” in step S236, adds “1” to the variable s in step S238, and proceeds to step S104 in FIG. 7A. Return.

  Then, the above-described processing of steps S104 to S232 is performed, and the above-described evaluation regarding the next lithium ion secondary battery BA specified by the variable s is performed. Then, until the variable s reaches the number smax of the lithium ion secondary batteries BA, in response to the designation of the next lithium ion secondary battery BA by the operator, “Yes” in step S234 and “No” in step S236. In step S238, the variable s is sequentially incremented, and the process consisting of steps S104 to S232 is sequentially performed on the lithium ion secondary battery BA designated by the incremented variable s, so that a plurality of lithium ions are obtained. Secondary batteries BA are evaluated one after another. When the variable s reaches the number smax of the lithium ion secondary batteries BA, the controller 70 determines “Yes” in step S236 and ends the execution of the evaluation program in step S240.

  In the embodiment operating as described above, the energization signal supply circuit 65 and the energization circuit 66 apply a DC voltage on which an alternating current component of a predetermined frequency is superimposed between the positive electrode and the negative electrode of the lithium ion secondary battery BA. As a result, a current corresponding to the AC component flows in the anode, cathode, and electrolyte in the lithium ion secondary battery BA, and a magnetic field is generated in a portion facing the lithium ion secondary battery BA. Then, this magnetic field is detected by the magnetic sensor 10, and the lithium ion secondary battery BA is evaluated based on the current flowing through each part in the lithium ion secondary battery BA calculated based on the detected magnetic field.

  In this case, the DC voltage on which the AC component is superimposed is a DC voltage that changes within the operating voltage range of the lithium ion secondary battery BA. The lithium ion secondary battery BA is repeatedly charged and discharged, and the lithium ion secondary battery BA is applied to the lithium ion secondary battery BA. A current flows. As a result, after the inspection, neither the overcharge state nor the overdischarge state occurs, and even during the inspection, the maximum value and the minimum value of the voltage applied between the electrodes of the secondary battery are always the operations of the secondary battery. Since it is maintained within the voltage range, there is no adverse effect on the secondary battery due to charging and discharging, and the secondary battery is inspected satisfactorily. Further, since only the signal representing the magnetic field generated in relation to the AC component of the predetermined frequency is taken out by the lock-in amplifier 69, a magnetic field that is not affected by the external magnetic field can be detected with a relatively simple configuration. . As a result, it is not necessary to make the external magnetic field uniform while suppressing the cost of the evaluation apparatus for the secondary battery, and the magnetic field generated by the current flowing through the plurality of portions of the lithium ion secondary battery BA is reduced. Since the detection can be performed with high accuracy, the performance of the lithium ion secondary battery BA can be evaluated with high accuracy.

  Further, in the above embodiment, the magnetic field at the position facing each part of the lithium ion secondary battery BA is detected by the processing of steps S26 to S66, and the current magnitude data Ixy (n, m) is processed by the processing of steps S102 to S126. , Current direction data θixy (n, m), current magnitude data Ix (n, m) in the X direction, and current magnitude data Iy (n, m) in the Y direction are calculated. The electrode position of the lithium ion secondary battery BA is detected by the processing of steps S130 to S156, and the electrode regions EP1, EP2,... Are detected by the processing of steps S160 to S186. Then, the electrolyte region ER through which current flows in the lithium ion secondary battery BA is detected by the processing of steps S190 to S204, and the current magnitude corresponding to a plurality of portions in the electrolyte region ER is detected by the processing of steps S210 to S220 and S224. The data Ixy (n, m) is extracted, and a graph representing the distribution state relating to the magnitudes of the plurality of extracted current magnitude data Ixy (n, m) is created and displayed on the display device 72. The graph in this case is a relational curve showing the relationship between the current magnitude and the proportion of current magnitude data Ixy (n, m) greater than or equal to the current magnitude. As a result, the operator can grasp the distribution state of the current flowing in each part of the electrolyte region ER from the graph displayed on the display device 72. That is, as described above, the operator can grasp the degree to which the current becomes small with respect to the large current flowing in a part of the route between the electrodes, and easily perform the performance of the lithium ion secondary battery BA including the degree of deterioration. Can be evaluated. Moreover, the electrolyte region ER is automatically detected, and the current magnitude data Ixy (n, m) corresponding to a plurality of portions in the electrolyte region ER is also automatically extracted, so that the performance of the lithium ion secondary battery BA Is easily evaluated.

  In addition, the relationship curve is obtained by dividing the current magnitude Ixy (n, m) of the electrolyte region by the maximum value MaxIxy of the current magnitude Ixy (n, m) by the processing of steps S210 and S212. It was created using the thickness ratio Irxy (n, m). According to this, the value of the X axis that is the axis of the current magnitude Ixy (n, m) in the relation curve is “1” at any maximum. In addition, since the Y axis of the ratio of the current magnitude ratio Irxy (n, m), which is another axis, is also “1” at the maximum, the scales of the X and Y axes of the relationship curve are constant in any case. Become. Therefore, the secondary battery can be easily evaluated by the relation curve regardless of the type of lithium ion secondary battery BA and the applied voltage.

  In the above-described embodiment, the integral value of the function that defines the relationship curve, that is, the area value Area of the region surrounded by the relationship curve and the X and Y axes is calculated by the processing in steps S222 and S224. 72. In this case, the integral value, that is, the area value Area is a large current when the ratio of the small current magnitude Ixy (n, m) is larger than the ratio of the large current magnitude Ixy (n, m). Since the ratio of the magnitude Ixy (n, m) is smaller than the ratio of the small current magnitude Ixy (n, m), the integral value, that is, the area value Area depends on the magnitude. In addition, the secondary battery including the degree of deterioration can be evaluated.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.

  In the above embodiment, the electrode regions EP1, EP2,... Are detected by the process of Step S130 in FIG. 7B to Step 186 in FIG. 7C using the current magnitude data Iy (n, m) in the Y direction at each detection position. Using the electrode regions EP1, EP2,..., The electrolyte region ER through which a current flows is detected by the processing in steps S190 to S204 in FIG. However, instead of this, if the evaluation time of the lithium ion secondary battery BA may be long, the operator determines the electrolyte region through which the current flows by looking at the current distribution image of the lithium ion secondary battery, and this The relationship curve shown in FIG. 14 is obtained using the current magnitude data Ixy (n, m) flowing through each part in the determined electrolyte region, or the area value Area of the region surrounded by the relationship curve and the XY coordinate axes is obtained. Or may be calculated.

  In the above embodiment, the electrolyte region ER is determined for each lithium ion secondary battery BA. However, in the case of evaluating a plurality of lithium ion secondary batteries BA of the same type, an electrolyte region ER through which a current flows is determined in advance, and current magnitude data flowing through each part within the predetermined electrolyte region ER The relationship curve shown in FIG. 14 may be obtained using Ixy (n, m), or the area value Area of the region surrounded by this relationship curve and the XY coordinate axes may be calculated.

  In the above embodiment, the current magnitude ratio Rate (p) occupied by the current magnitude ratio Irxy (n, m) greater than or equal to the current magnitude ratio p is calculated by the process of step S216 of FIG. A graph representing a change in the current magnitude ratio Rate (p) is created by the above process, and the created graph is displayed on the display device 72. However, instead of this, a current magnitude ratio Rate (p) occupied by a current magnitude ratio Irxy (n, m) equal to or smaller than the current magnitude ratio p is calculated in step S216, and this calculation is performed in step S224. A graph representing the change in the current ratio ratio Rate (p) may be created and the created graph may be displayed on the display device 72. In this case, the current magnitude ratio Rate (p) is equal to the value subtracted from “1” in the above embodiment.

  Therefore, in the case of the lithium ion secondary battery BA having the characteristics shown by the solid line A in FIG. 14, as shown in FIG. 16, with respect to a straight line parallel to the X axis where the Y axis value is 0.5, The relationship curve is symmetrical to the relationship curve indicated by the solid line A. Further, in the case of the lithium ion secondary battery BA having the characteristics shown by the broken line B in FIG. 14, as shown in FIG. 16, with respect to a straight line parallel to the X axis where the Y axis value is 0.5, The relationship curve is symmetrical to the relationship curve indicated by the broken line B. Also in this case, if the performance of the lithium ion secondary battery BA is good and the ratio of the large current magnitude Ixy (n, m) is larger than the small current magnitude Ixy (n, m), the relationship The curve is not indicated by the broken line B but indicated by the solid line A. On the contrary, the performance is not good due to the progress of deterioration of the lithium ion secondary battery BA, and the ratio of the small current magnitude Ixy (n, m) is larger than the large current magnitude Ixy (n, m). If it is larger, the relationship curve is indicated by a broken line B. Also by this, the performance of the lithium ion secondary battery BA can be evaluated by the graph display.

In this modification, the area value Area of the region surrounded by the relationship curve calculated in step S222 and the X and Y axes is the current magnitude ratio Rate (p) of “1” in the above embodiment. Since it is equal to the value obtained by subtracting from, it is calculated by the following equation (15).
Area = 1−ΣIrxy (n, m) / number of B (n, m) Equation 15
In this modification, contrary to the above-described embodiment, the performance of the lithium ion secondary battery BA is good and the ratio of the large current magnitude Ixy (n, m) is small. , M), the area value Area (integral value of the present invention) surrounded by the relationship curve and the X and Y axes is small. On the contrary, the performance is not good due to the progress of deterioration of the lithium ion secondary battery BA, and the ratio of the small current magnitude Ixy (n, m) is larger than the large current magnitude Ixy (n, m). If it is larger, the area value Area becomes larger. Therefore, the performance of the lithium ion secondary battery BA can also be evaluated by displaying the area value Area.

  In the above embodiment or modification, the current magnitude ratio Rate (p) occupied by the current magnitude ratio Irxy (n, m) that is greater than or equal to the current magnitude ratio p is calculated, and the current magnitude ratio ratio is calculated. A graph representing the change in Rate (p) was created and the created graph was displayed on the display device 72. However, instead of this, the current magnitude ratio Rate (p) occupied by the current magnitude ratio Irxy (n, m) equal to the current magnitude ratio p is calculated in step S216, and this calculation is performed in step S224. A graph representing the change in the current ratio ratio Rate (p) may be created and the created graph may be displayed on the display device 72. In this case, if the performance of the lithium ion secondary battery BA is good and the ratio of the large current magnitude Ixy (n, m) is larger than the small current magnitude Ixy (n, m), the solid line in FIG. This is indicated by A. On the contrary, the performance is not good due to the progress of deterioration of the lithium ion secondary battery BA, and the ratio of the small current magnitude Ixy (n, m) is larger than the large current magnitude Ixy (n, m). If it is larger, the relationship curve is shown by a broken line B in FIG. Also by this, the performance of the lithium ion secondary battery BA can be evaluated by the graph display of the relationship curve.

  Moreover, in the said embodiment and modification, the relationship curve was created using the electric current magnitude ratio p. However, when evaluating by applying voltage to the same type of lithium ion secondary battery BA under the same conditions, the current magnitude data Ixy (n, m) is used as it is instead of the current magnitude ratio p, and the relationship curve is used. May be created. In this case, since the maximum value of the current magnitude data Ixy (n, m) changes variously, the X coordinate value of the relational curve with the Y coordinate value “0” is not “1” as in the above embodiment. Variously. However, if the type and voltage application conditions of the lithium ion secondary battery BA are fixed, each lithium ion secondary battery BA can be evaluated by comparing the relationship curves between different lithium ion secondary batteries BA. Further, each lithium ion secondary battery BA can be evaluated by comparing the area value Area of the area surrounded by the relationship curve and the X and Y coordinate axes.

  In the above embodiment, the performance of the lithium ion secondary battery BA is evaluated using the current magnitude Ixy obtained from the magnetic field detected by the magnetic sensor 10. However, the magnetic field strength Hxy and the current magnitude Ixy are in a proportional relationship, and the magnetic field direction θxy and the current direction Ixy differ only by 90 degrees, so that instead of the current magnitude Ixy, The lithium ion secondary battery BA may be evaluated using the strength Hxy. In this case, the processes in steps S10 to S80 and S102 to S124 are opposed to the plurality of portions instead of the plurality of current magnitudes Ixy (n, m) flowing in the plurality of portions of the lithium ion secondary battery BA. A plurality of magnetic field strengths Hxy (n, m) at the position are respectively calculated as a plurality of physical quantities to be evaluated, and the calculated plurality of magnetic field strengths Hxy (n, m) are obtained by the processes of steps S190 to S204 and S212. ), A plurality of magnetic field strengths Hxy (n, m) corresponding to a plurality of portions in the electrolyte region ER are extracted, and a plurality of magnetic field strengths Hxy (extracted by the processing of S210 to S220, S224). A graph representing the distribution state of (n, m) may be created and displayed.

  Also in this case, the relationship curve representing the distribution state of the plurality of magnetic field strengths Hxy (n, m) is obtained by calculating the magnetic field strength Hxy (n, m) in the electrolyte region by the processing in steps S210 and S212. The magnetic field strength ratio Hrxy (n, m) divided by the maximum value MaxHxy of the magnetic field strength Hxy (n, m) may be used. Then, the integrated value of the function that defines the relationship curve, that is, the area value Area of the region surrounded by the relationship curve and the X and Y axes may be calculated and displayed on the display device 72 by the processing of steps S222 and S224.

  Further, when a graph representing the distribution state of a plurality of magnetic field strengths Hxy (n, m) is used, the magnetic field strength equal to or smaller than the magnetic field strength ratio p in step S216 as in the modification of the above embodiment. The magnetic field strength ratio rate Rate (p) occupied by the ratio Hrxy (n, m) is calculated, and a graph representing the change in the calculated magnetic field strength ratio rate Rate (p) is created in step S224. The graph may be displayed on the display device 72. In step S216, the magnetic field strength ratio Rate (p) occupied by the magnetic field strength ratio Hrxy (n, m) equal to the magnetic field strength ratio p is calculated. In step S224, the calculated magnetic field strength ratio is calculated. A graph representing a change in the rate Rate (p) may be created and the created graph may be displayed on the display device 72. As described above, even when the magnetic field strength Hxy (n, m) is used, the performance of the lithium ion secondary battery BA can be evaluated as in the case where the current magnitude Ixy (n, m) is used.

  Further, when the magnetic field strength Hxy (n, m) is used, as in the case of the modified example, in the case where evaluation is performed by applying a voltage to the same type of lithium ion secondary battery BA under the same conditions, The relationship curve may be created using the magnetic field strength data Hxy (n, m) instead of the magnetic field strength ratio p. Also by this, the performance of the lithium ion secondary battery BA is evaluated.

  Further, in the above embodiment, the energization voltage applied to the lithium ion secondary battery BA by the energization circuit 66 does not always exceed the operating voltage range of the lithium ion secondary battery BA. However, the center voltage of fluctuation of the energization voltage, that is, the DC voltage on which the AC signal is superimposed is within the operating voltage range of the lithium ion secondary battery BA, that is, the lower limit value of the discharge voltage of the lithium ion secondary battery BA and the charge voltage There is no major problem as long as it is below the upper limit. In this case, if the DC voltage on which the AC signal is superimposed is close to the upper limit of the operating voltage range (that is, the charging voltage) of the lithium ion secondary battery BA, during the inspection, the energization voltage (voltage at the time of charging) is the lithium ion 2. The upper limit of the operating voltage range of the secondary battery BA may be exceeded. Further, if the DC voltage on which the AC signal is superimposed is close to the lower limit of the operating voltage range (that is, the discharge voltage) of the lithium ion secondary battery BA, the energization voltage (the voltage at the time of discharge) is increased during the inspection. In some cases, the operating voltage range of the battery BA is lower than the lower limit. However, the output voltage of the lithium ion secondary battery BA after the inspection is within the operating voltage range, and the lithium ion secondary battery BA after the inspection is not overcharged or overdischarged. The effect on the battery BA is not so great.

  Further, in the above-described embodiment, the DC voltage on which the AC signal that changes around “0” supplied from the energization signal supply circuit 65 is superimposed by the energization circuit 66 is always constant. However, instead of this, the DC voltage on which the AC signal is superimposed may be the same as the output voltage of the lithium ion secondary battery BA before the inspection. In this case, the output voltage of the lithium ion secondary battery BA may be automatically measured before the inspection, and the energization circuit 66 may automatically superimpose the AC signal on the measured output voltage. In addition, the operator measures the output voltage of the lithium ion secondary battery BA before the inspection, and inputs the measured voltage to the controller 70 using the input device 71. The controller 70 controls the energization circuit 66 to measure the voltage. The AC signal may be superimposed on the voltage. Also in this case, if the output voltage of the lithium ion secondary battery BA before the inspection is close to the upper limit or the lower limit of the operating voltage range of the lithium ion secondary battery BA, as described above, The operating voltage range of the lithium ion secondary battery BA may be exceeded. However, also in this case, as described above, the problem given to the lithium ion secondary battery BA is not so great.

  On the other hand, according to this modification, the voltage applied between the anode and the cathode of the lithium ion secondary battery BA by the energization circuit 66 changes up and down around the output voltage of the lithium ion secondary battery BA before the inspection. Thus, charging and discharging are repeated, so that the output voltage of the lithium ion secondary battery BA after the inspection becomes the same as the output voltage before the inspection. As a result, the state of the lithium ion secondary battery BA can be kept almost the same before and during the inspection, and can be kept the same as before the inspection after the inspection. The performance of the lithium ion secondary battery BA can be evaluated, and other inspections and operations can be realized while maintaining the same state.

  Moreover, in the said embodiment, the stage 40 which can set several lithium ion secondary battery BA was used, and it was made to evaluate several lithium ion secondary battery at once. However, when evaluating the lithium ion secondary batteries BA one by one, a stage 40 on which only one lithium ion secondary battery BA can be set is prepared. What is necessary is just to scan the circumference | surroundings with the magnetic sensor 10. FIG. According to this, when evaluating a plurality of lithium ion secondary batteries, although the evaluation time is longer than that of the above embodiment, the evaluation device can be configured compactly.

  Moreover, in the said embodiment, the one magnetic sensor 10 was moved to the X direction and the Y direction, and several lithium ion secondary battery BA was evaluated. However, a plurality of magnetic sensors may be arranged in a matrix below the stage 40, and a plurality of lithium ion secondary batteries BA may be evaluated without moving the plurality of magnetic sensors. In addition, a plurality of magnetic sensors are provided in one row along the X direction, a plurality of magnetic sensors are provided in one row along the Y direction, or a small number of magnetic sensors are provided in a matrix in the X and Y directions. Then, the plurality of lithium ion secondary batteries may be evaluated by appropriately moving these magnetic sensor groups and scanning the plurality of lithium ion secondary batteries.

  In the above embodiment, a magnetoresistive element (MR element) is used as the magnetic sensor. Instead, a Hall element, a magneto-impedance element effect sensor, a flux gate, a superconducting quantum interference element, or the like is used. May be.

  Moreover, in the said embodiment, although the evaluation apparatus based on this invention was utilized for the test | inspection of the lithium ion secondary battery BA, evaluation apparatuses based on this invention are lithium, such as a nickel cadmium secondary battery and a nickel hydride secondary battery. The present invention can also be applied to rechargeable secondary batteries other than the ion secondary battery BA. In this case, when the secondary battery cannot be set on the battery setting table 50 of the above embodiment, a stage 40 and a battery setting table 50 different from those of the above embodiment are prepared according to the shape and size of the secondary battery. You just have to do it. Further, even if it is a lithium ion secondary battery, when the secondary battery cannot be set on the battery setting table 50 of the above embodiment, the stage 40 and the battery setting table 50 suitable for the lithium ion secondary battery are prepared. What should I do?

DESCRIPTION OF SYMBOLS 10 ... Magnetic sensor, 20 ... X direction slide mechanism, 25 ... X direction motor, 30 ... Y direction slide mechanism, 34 ... Y direction motor, 40 ... Stage, 50 ... Table for battery set, 61 ... X direction position detection circuit, 62 ... X direction feed motor control circuit, 63 ... Y direction position detection circuit, 64 ... Y direction feed motor control circuit, 65 ... energization signal supply circuit, 66 ... energization circuit, 67 ... energization selection circuit, 68 ... sensor signal extraction circuit 69 ... Lock-in amplifier, 70 ... Controller, 72 ... Display device

Claims (14)

Energization means for applying a voltage between the electrodes of the secondary battery to flow current;
A magnetic field detecting means positioned opposite to a plurality of parts of the secondary battery, detecting a magnetic field generated by a current flowing through the plurality of parts, and outputting a signal representing the detected magnetic field;
From the signal representing the detected magnetic field output from the magnetic field detection means, the magnitudes of the plurality of currents flowing through the plurality of portions of the secondary battery or the strengths of the plurality of magnetic fields at positions facing the plurality of portions are plural. An evaluation target physical quantity calculating means for calculating each of the evaluation target physical quantities;
Evaluation target physical quantity extraction for extracting a plurality of evaluation target physical quantities corresponding to a plurality of portions in the electrolyte region located between the electrodes of the secondary battery among the plurality of evaluation target physical quantities calculated by the evaluation target physical quantity calculation means Means,
An evaluation apparatus for a secondary battery, comprising: a graph display means for creating and displaying a graph representing a distribution state of a plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction means. The evaluation apparatus for a secondary battery according to claim 1,
The graph representing the distribution state of the sizes of the plurality of evaluation target physical quantities includes the size of the evaluation target physical quantity and the size of the evaluation target physical quantity among the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction unit. An evaluation apparatus for a secondary battery, characterized in that it is a relational curve showing a relation with a ratio of the size of the physical quantity to be evaluated described above or below. The evaluation apparatus for a secondary battery according to claim 2, further comprising:
An evaluation apparatus for a secondary battery, comprising: an integral value display means for calculating and displaying an integral value of a function defining the relation curve. The evaluation apparatus for a secondary battery according to claim 1,
The graph representing the distribution state of the sizes of the plurality of evaluation target physical quantities includes the size of the evaluation target physical quantity and the size of the evaluation target physical quantity among the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction unit. An evaluation apparatus for a secondary battery, wherein the evaluation curve is a relational curve showing a relation with a ratio occupied by. In the evaluation apparatus of the secondary battery as described in any one of Claims 2 thru | or 4,
The relation curve is created using the magnitude of the evaluation target physical quantity divided by the maximum value of the magnitudes of the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extracting means. Battery evaluation device. The evaluation apparatus for a secondary battery according to any one of claims 1 to 5,
The evaluation target physical quantity extracting means includes an electrolyte region determining means for determining the electrolyte region using a plurality of evaluation target physical quantities calculated by the evaluation target physical quantity calculating means. The evaluation apparatus for a secondary battery according to any one of claims 1 to 6,
The energization means applies a DC voltage obtained by superimposing an AC component of a predetermined frequency on the DC voltage between the electrodes of the secondary battery,
The evaluation apparatus for a secondary battery, wherein the magnetic field detection means detects a magnetic field changing at a frequency equal to the predetermined frequency and outputs a signal representing the detected magnetic field. In the evaluation apparatus of the secondary battery according to claim 7,
The evaluation apparatus for a secondary battery, wherein the DC voltage before the AC component is superimposed is within an operating voltage range of the secondary battery. Energization means for applying a voltage between the electrodes of the secondary battery to flow current;
Evaluation of a secondary battery provided with magnetic field detection means positioned opposite to a plurality of parts of the secondary battery, detecting a magnetic field generated by the current flowing through the plurality of parts, and outputting a signal representing the detected magnetic field Applied to the device,
From the signal representing the detected magnetic field output from the magnetic field detection means, the magnitudes of the plurality of currents flowing through the plurality of portions of the secondary battery or the strengths of the plurality of magnetic fields at positions facing the plurality of portions are plural. An evaluation target physical quantity calculation step for calculating each of the evaluation target physical quantities;
Evaluation target physical quantity extraction for extracting a plurality of evaluation target physical quantities corresponding to a plurality of portions in an electrolyte region located between electrodes of a secondary battery among a plurality of evaluation target physical quantities calculated by the evaluation target physical quantity calculation step Steps,
A method of evaluating a secondary battery, comprising: a graph display step of creating and displaying a graph representing a distribution state of a plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction step. The secondary battery evaluation method according to claim 9,
The graph representing the distribution state of the sizes of the plurality of evaluation target physical quantities includes a size of the evaluation target physical quantity and a size of the evaluation target physical quantity among the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction step. An evaluation method for a secondary battery, characterized in that it is a relational curve showing a relation with a ratio of the size of the physical quantity to be evaluated described above or below. The method for evaluating a secondary battery according to claim 9, further comprising:
An evaluation method for a secondary battery, comprising: an integral value display step of calculating and displaying an integral value of a function defining the relation curve. The secondary battery evaluation method according to claim 9,
The graph representing the distribution state of the sizes of the plurality of evaluation target physical quantities includes a size of the evaluation target physical quantity and a size of the evaluation target physical quantity among the plurality of evaluation target physical quantities extracted by the evaluation target physical quantity extraction step. A method for evaluating a secondary battery, characterized in that the curve is a relational curve indicating a relation with a ratio occupied by. In the evaluation method of the rechargeable battery according to any one of claims 10 to 12,
The relation curve is created using the magnitude of the evaluation target physical quantity divided by the maximum value of the magnitudes of the plurality of evaluation target physical quantities extracted in the evaluation target physical quantity extraction step. Battery evaluation method. In the evaluation method of the rechargeable battery given in any 1 paragraph of Claims 9 thru / or 13,
The evaluation target physical quantity extraction step includes an electrolyte region determination step of determining the electrolyte region using a plurality of evaluation target physical quantities calculated by the evaluation target physical quantity calculation step.

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