Detection system and detection method

Abstract

A detection system (1) for detecting whether or not the connection of connection portions where a plurality of electrode tabs in a wound battery (A) are connected to an external electrode is good, the detection system (1) being provided with: a power supply unit (22) for supplying a current between a positive electrode tab (B11) of the wound battery (A) and a negative electrode tab (C11) of the wound battery (A); a detection unit (4) that detects a magnetic field caused by the supply of current to the wound battery (A); and a processing unit (24) that determines whether or not the connection of the connection portion is good on the basis of the magnitude of the magnetic field.

Description

Technical Field

[0001] The present invention relates to a detection system and a detection method for detecting whether the connection of an electrode sheet of a wound battery is good. Background Art

[0002] JP2002-008709A discloses a wound-type battery in which a positive electrode and a negative electrode having an electrode active material formed on a strip-shaped current collector are stacked with a separator interposed therebetween.

[0003] Furthermore, in the invention described in JP2002-008709A, when a plurality of electrode sheets (specifically, positive electrode sheets and negative electrode sheets) are connected to external electrodes, poor connection is likely to occur.

[0004] Conventionally, as a method for detecting such a connection failure, the internal resistance of a wound battery is detected, and whether the connection is good or not is determined based on the detected internal resistance. Summary of the invention

[0005] However, in the conventional detection method, there is a problem that a connection failure cannot be detected with high accuracy because the contact resistance of the electrode accounts for an extremely small proportion of the internal resistance of the wound battery.

[0006] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a detection system and a detection method which can detect with high accuracy whether the connection of the electrode tabs of a wound battery is good or not.

[0007] According to one embodiment of the present invention, a detection system is provided for detecting whether the connection between a plurality of electrode sheets in a wound battery and a connecting portion connected to an external electrode is good, the detection system comprising: a power supply unit or a discharge unit for supplying power or discharging power between a positive electrode sheet of the wound battery and a negative electrode sheet of the wound battery; a detection unit for detecting magnetic field-related parameters caused by supplying power to the wound battery or discharging from the wound battery; and a processing unit for determining whether the connection of the connecting portion is good based on the detected magnetic field-related parameters.

[0008] According to another embodiment of the present invention, a detection method is provided for detecting whether the connection between a plurality of electrode sheets in a wound battery and a connecting portion connected to an external electrode is good, the detection method comprising: a power supply or discharge step for performing power supply or discharge between a positive electrode sheet of the wound battery and a negative electrode sheet of the wound battery; a detection step for detecting magnetic field-related parameters caused by power supply to the wound battery or discharge from the wound battery; and a determination step for determining whether the connection of the connecting portion is good based on the detected magnetic field-related parameters.

[0009] According to the aspect of the present invention, it is possible to detect with high accuracy whether the connection between the plurality of electrode tabs of a wound battery and the external electrodes is good or not. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic cross-sectional view showing the structure of a wound-type battery according to the first embodiment.

[0011] Figure 2 It is a schematic explanatory diagram showing each configuration of the detection system according to the first embodiment.

[0012] Figure 3 It is a block diagram showing the components of the detection device constituting the detection system according to the first embodiment.

[0013] Figure 4 It is a flowchart showing each step of the detection method implemented by the detection system of the first embodiment.

[0014] Figure 5A This is a schematic development view showing a connection failure of a single positive electrode sheet located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery.

[0015] Figure 5B This is a schematic perspective view showing a connection failure of a single positive electrode sheet located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery.

[0016] Fig. 6A This is a schematic development view showing poor connection of a plurality of positive electrode sheets located on the outer peripheral side of a connection portion where the plurality of electrode sheets are connected to an external electrode in a wound-type battery.

[0017] Figure 6B This is a schematic perspective view showing a connection failure of a plurality of positive electrode sheets located on the outer peripheral side of a connection portion where the plurality of electrode sheets are connected to an external electrode in a wound type battery.

[0018] Fig. 7A This is a schematic development view showing a connection failure of a single negative electrode sheet located on the innermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery.

[0019] Figure 7B This is a schematic perspective view showing a connection failure of a single negative electrode sheet located on the innermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound type battery.

[0020] Fig. 8A This is a schematic development view showing poor connection of a plurality of negative electrode sheets located on the inner circumference side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery.

[0021] Figure 8BThis is a schematic perspective view showing a connection failure of a plurality of negative electrode sheets located on the inner circumference side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound type battery.

[0022] Fig. 9 It is a schematic explanatory diagram showing each configuration of a detection system according to a modified example.

[0023] Fig. 10A It is a schematic development view showing a connection failure of a single negative electrode sheet located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery according to a modified example.

[0024] Fig. 10B This is a schematic perspective view showing a connection failure of a single negative electrode sheet located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery according to a modified example.

[0025] Fig.11A It is a schematic development view showing a connection failure of a plurality of negative electrode sheets located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery according to a modification.

[0026] Fig. 11B This is a schematic perspective view showing a connection failure of a plurality of negative electrode sheets located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound-type battery according to a modified example.

[0027] Fig.12 It is a schematic explanatory diagram showing each configuration of the detection system according to the second embodiment.

[0028] Fig.13 It is a flowchart showing each step of the detection method implemented by the detection system of the second embodiment.

[0029] Fig.14 It is a flowchart showing each step of the detection method according to the modification example of the second embodiment.

[0030] Fig.15 It is a schematic explanatory diagram showing each configuration of a detection system according to a third embodiment.

[0031] Fig.16 This is a schematic explanatory diagram showing an example of a plurality of detection locations according to the third embodiment.

[0032] Fig.17 It is a flowchart showing each step of the detection method performed by the detection system of the third embodiment.

[0033] Fig.18 This is a graph comparing the ideal characteristic curve, the characteristic curve of good products, and the characteristic curve of defective products.

[0034] Fig.19 This is an explanatory diagram showing an example of calculation of the degree of consistency. DETAILED DESCRIPTION

[0035] Hereinafter, the mode for implementing the present invention will be described with reference to the drawings. In this specification, the same elements are denoted by the same reference numerals throughout the entirety.

[0036] [First embodiment]

[0037] Below, refer to Figures 1 to 11B The wound battery A, the detection system 1, and the detection method according to the first embodiment will be described.

[0038] [Structure of wound battery]

[0039] First, refer to Figure 1 The structure of the wound battery A to be tested according to the first embodiment will be described.

[0040] Figure 1 It is a schematic cross-sectional view showing the structure of a wound battery A according to the first embodiment.

[0041] like Figure 1 As shown, the wound battery A of the first embodiment is a lithium ion battery in which a sheet-shaped positive electrode layer B and a sheet-shaped negative electrode layer C are stacked and wound with a separator (not shown) as an insulator. The wound battery A is sealed in a housing (not shown) for use. It should be noted that the separator prevents short circuits between the positive electrode layer B and the negative electrode layer C, but allows electrons to move between the positive electrode layer B and the negative electrode layer C.

[0042] The wound battery A includes a positive electrode sheet group B1 disposed at one end and a negative electrode sheet group C1 disposed at one end in a manner not to interfere with the positive electrode sheet group B1 (i.e., away from the positive electrode sheet group B1). The positive electrode sheet group B1 is formed by joining (specifically, welding) a plurality of positive electrode sheets B11 arranged in a manner protruding from one end of each wound positive electrode layer B and arranged along the wall thickness direction of the wound battery A. Similarly, the negative electrode sheet group C1 is formed by joining (specifically, welding) a plurality of negative electrode sheets C11 arranged in a manner protruding from one end of each wound negative electrode layer and arranged along the wall thickness direction of the wound battery A.

[0043] The positive electrode sheet group B1 and the negative electrode sheet group C1 are connected to a sheet-shaped first external electrode D1 as an external electrode and a sheet-shaped second external electrode D2 as an external electrode by bonding (specifically, welding). In the first embodiment, the upper surface of one surface of the first external electrode D1 and the upper surface of one surface of the second external electrode D2 are connected to the lower surface of the positive electrode sheet B11 located on the innermost peripheral side in the positive electrode sheet group B1 and the lower surface of the negative electrode sheet C11 located on the outermost peripheral side in the negative electrode sheet group C1, respectively.

[0044] Furthermore, the connection portions where the plurality of electrode sheets (specifically, the positive electrode sheet B11 and the negative electrode sheet C11) in the wound battery A are connected to the external electrodes (specifically, the first external electrode D1 and the second external electrode D2) by bonding (e.g., welding) are prone to poor connection. Therefore, the inventors have conducted in-depth research and have invented a detection system 1 (see Figure 2 ) and a detection method implemented by the detection system 1. It should be noted that the details of the detection system 1 and the detection method will be described later.

[0045] [Composition of the detection system]

[0046] Next, refer to Figure 2 and Figure 3 , a detection system 1 according to a first embodiment will be described.

[0047] Figure 2 It is a schematic explanatory diagram showing each configuration of the detection system 1 according to the first embodiment. Figure 3 It is a block diagram showing the components of the detection device 2 constituting the detection system 1 according to the first embodiment.

[0048] like Figure 2 As shown, the detection system 1 of the first embodiment is a system for detecting whether the connection between the plurality of electrode sheets (specifically, the positive electrode sheet B11 and the negative electrode sheet C11) and the external electrodes (specifically, the first external electrode D1 and the second external electrode D2) in the wound battery A is good. The detection system 1 includes a detection device 2, a current wiring 3, a detection unit 4, and a detection wiring 5.

[0049] like Figure 3As shown, the detection device 2 has an input interface 21, a power supply unit 22, a storage unit 23, a processing unit 24, and a display unit 25 as a notification unit. In the first embodiment, the power supply unit 22, the storage unit 23, the processing unit 24, and the display unit 25 are formed in a manner of being built into the detection device 2, but it is not limited to this, for example, they can also be formed separately. In addition, when the power supply unit 22, the storage unit 23, the processing unit 24, and the display unit 25 are built into the detection device 2, the overall simplification of the detection system 1 can be achieved.

[0050] The detection result detected by the detection unit 4 is input to the input interface 21 . The input interface 21 outputs the detection result from the detection unit 4 to the processing unit 24 .

[0051] The power supply unit 22 supplies current (specifically, a specified DC current pre-stored in the storage unit 23) between the positive electrode sheet group B1 (i.e., multiple positive electrode sheets B11) of the wound battery A and the negative electrode sheet group C1 (i.e., multiple negative electrode sheets C11) of the wound battery A via the first external electrode D1 and the second external electrode D2.

[0052] The storage unit 23 stores processing programs and algorithm programs executed in the processing unit 24. In addition, the storage unit 23 temporarily stores the detection results detected by the detection unit 4 via the input interface 21. In the first embodiment, the storage unit 23 and the processing unit 24 are provided separately, but the present invention is not limited thereto, and the storage unit 23 may also be built into the processing unit 24.

[0053] The storage unit 23 stores a predetermined DC current to be supplied between the positive electrode sheet group B1 of the wound battery A and the negative electrode sheet group C1 of the wound battery A, a predetermined threshold used in the determination process of whether the connection is good or not by the processing unit 24, and a table used in the identification process of the poorly connected electrode sheet. It should be noted that the table is composed of a plurality of magnetic field magnitude ranges, the directions of the magnetic field (positive or negative) corresponding to the plurality of magnetic field magnitude ranges, and a plurality of poorly connected electrode sheets corresponding to the two.

[0054] The processing unit 24 determines whether the connection of the connection part (specifically, the electrode sheet) is good based on the detection result from the detection unit 4, and outputs the determination result to the display unit 25. In addition, when the connection of the connection part is determined to be poor, the processing unit 24 determines the electrode sheet with poor connection, and outputs the determination result to the display unit 25. In addition, in the first embodiment, the processing unit 24 is composed of a CPU (Central Processing Unit: central processing unit) as a computer, but it is not limited to this. The processing unit 24 can also be composed of, for example, a plurality of microcomputers. It should be noted that the details of the processing unit 24 will be described later.

[0055] The display unit 25 is a means for notifying the determination result output from the processing unit 24 or a display for displaying the determination result. In the first embodiment, the notification unit is constituted by the display unit 25, but the present invention is not limited thereto, and the notification unit may be constituted by a speaker, for example.

[0056] return Figure 2 The current wiring 3 includes a first current wiring 31 connecting the power supply part 22 of the detection device 2 with the positive electrode sheet group B1 (ie, multiple positive electrode sheets B11) and a second current wiring 32 connecting the power supply part 22 with the negative electrode sheet group C1 (ie, multiple negative electrode sheets C11).

[0057] One end of the first current wiring 31 is connected to one end of the power supply unit 22, and the other end of the first current wiring 31 is connected to the positive electrode sheet group B1 via the first external electrode D1. Similarly, one end of the second current wiring 32 is connected to the other end of the power supply unit 22, and the other end of the second current wiring 32 is connected to the negative electrode sheet group C1 via the second external electrode D2.

[0058] From the viewpoint of suppressing the generation of an external magnetic field, it is preferred that the first current wiring 31 and the second current wiring 32 are composed of magnetic shielding wiring. In this case, there is no need to provide another magnetic shielding unit, and the overall simplification of the detection system 1 can be achieved. On the other hand, the first current wiring 31 and the second current wiring 32 may also be composed of a four-terminal pair measurement structure wiring, a twisted wiring, or a coaxial wiring, instead of being composed of magnetic shielding wiring.

[0059] The detection unit 4 detects a magnetic field as a magnetic field-related parameter caused by supplying current to the wound battery A. The detection unit 4 includes: a first detection sensor 41 as a first detection unit, which is provided close to the wound battery A and detects a first magnetic field as a magnetic field (specifically, a magnetic field including an external magnetic field); and a second detection sensor 42 as a second detection unit, which is provided farther from the wound battery A than the first detection sensor 41 and detects a second magnetic field as an external magnetic field.

[0060] The first detection sensor 41 is a sensor for detecting a first magnetic field in the axial direction of the wound battery A, and the second detection sensor 42 is a sensor for detecting a second magnetic field in the axial direction of the wound battery A. Thus, the generation of noise caused by an external magnetic field or the like can be suppressed, and the detection accuracy can be improved, so whether the connection of the connection portion is good or not can be detected with higher accuracy.

[0061] In addition, the first detection sensor 41 and the second detection sensor 42 are both provided on one end side or the other end side of the wound battery A. Thus, the first magnetic field and the second magnetic field caused by the current flowing in the winding direction of the wound battery A can be detected with high accuracy, and thus it is possible to detect with higher accuracy whether the connection of the connection part is good. In the first embodiment, the first detection sensor 41 and the second detection sensor 42 are respectively provided on one end side of the wound battery A (i.e., the side provided with the electrode sheet) and the other end side of the wound battery A (i.e., the side without the electrode sheet).

[0062] The detection wiring 5 is a wiring connecting the detection unit 4 and the processing unit 24. Specifically, the detection wiring 5 includes a first detection wiring 51 connecting the first detection sensor 41 and the processing unit 24 and a second detection wiring 52 connecting the second detection sensor 42 and the processing unit 24.

[0063] From the viewpoint of being less susceptible to the influence of the external magnetic field, the first detection wiring 51 and the second detection wiring 52 are preferably composed of magnetic shielding wiring. In this case, there is no need to set up another magnetic shielding unit, which can simplify the entire detection system 1. On the other hand, the first detection wiring 51 and the second detection wiring 52 can also be composed of a four-terminal pair measurement structure wiring, a twisted wiring or a coaxial wiring instead of a magnetic shielding wiring.

[0064] [Detection method implemented by the detection system]

[0065] Next, refer to Figures 4 to 8B , the detection method of the first embodiment is described.

[0066] Figure 4 It is a flowchart showing each step of the detection method implemented by the detection system 1 of the first embodiment. Figure 5A 1 is a schematic development diagram showing a connection failure of a single positive electrode tab B11_6 located on the outermost peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound battery A. FIG. Figure 5B This is a schematic perspective view showing a connection failure of a single positive electrode tab B11_1 located on the outermost peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound battery A. Fig. 6A It is a schematic development view showing a connection failure of a plurality of positive electrode tabs B11_4 to B11_6 located on the outer peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound type battery A. Figure 6B This is a schematic perspective view showing a connection failure of a plurality of positive electrode tabs B11_4 to B11_6 located on the outer peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound type battery A. Fig. 7A1 is a schematic development diagram showing a connection failure of a single negative electrode tab C11_1 located on the innermost peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound battery A. FIG. Figure 7B 1 is a schematic perspective view showing a connection failure of a single negative electrode tab C11_1 located on the innermost peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound battery A. FIG. Fig. 8A 1 is a schematic development diagram showing a connection failure of a plurality of negative electrode sheets C11_1 to C11_3 located on the inner circumference side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound type battery A. FIG. Figure 8B 1 is a schematic perspective view showing poor connection of a plurality of negative electrode sheets C11_1 to C11_3 located on the inner circumference of the connection portion where the plurality of electrode sheets are connected to the external electrode in the wound battery A. Figure 5A , Fig. 6A , Fig. 7A as well as Fig. 8A As shown in FIG. 1 , as an example, the wound battery A to be inspected for good connection has six positive electrode sheets B11_1 to B11_6 and six negative electrode sheets C11_1 to C11_6 in order from the inner circumference to the outer circumference. Figure 5A , Fig. 6A , Fig. 7A as well as Fig. 8A As shown, the arrows drawn on the positive electrode layer B and the negative electrode layer C indicate the directions of electrons.

[0067] When the switch of the detection device 2 is switched from off to on by the user, each step of the detection method implemented by the detection system 1 is executed.

[0068] like Figure 4 As shown, first, in step S1, the power supply unit 22 supplies a predetermined DC current between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A via the current wiring 3, and then proceeds to step S2. Then, in the event of a poor connection of the connection portion (specifically, the electrode sheet), the current flows in the winding direction of the wound battery A (see Figure 5B , Figure 6B , Figure 7B as well as Figure 8B On the other hand, when there is no poor connection of the connection portion (specifically, the electrode sheet), the current does not flow in the winding direction of the wound battery A, or the current flowing in the winding direction of the wound battery A is weak, so no magnetic field is generated around it.

[0069] Next, in step S2, the first detection sensor 41 and the second detection sensor 42 respectively detect the first magnetic field and the second magnetic field caused by the current flowing in the winding direction of the wound battery A. Then, the first detection sensor 41 and the second detection sensor 42 output the detected first magnetic field and the second magnetic field to the processing unit 24 via the input interface 21, and the process proceeds to step S3.

[0070] Next, in step S3, the processing unit 24 removes the external magnetic field based on the first magnetic field and the second magnetic field output from the first detection sensor 41 and the second detection sensor respectively, calculates the third magnetic field which is the magnetic field caused only by the current flowing in the winding direction of the wound battery A, and enters step S4.

[0071] In the first embodiment, in step S3, the processing unit 24 removes the external magnetic field based on the difference between the first magnetic field and the second magnetic field, thereby calculating the third magnetic field. In this way, the influence of the external magnetic field on the determination of whether the connection is good or not can be removed, so that whether the connection of the connection part is good or not can be detected with higher accuracy. However, in step S3, the processing unit 24 is not limited to this. For example, in the case where the first detection sensor 41 and the second detection sensor 42 are respectively provided at one end side of the wound battery A and the other end side of the wound battery A, the external magnetic field can also be removed based on the addition operation of the first magnetic field and the second magnetic field to calculate the third magnetic field.

[0072] Next, in step S4 , the processing unit 24 determines whether the connection of the connection portion (specifically, the plurality of positive electrode sheets B11 and the plurality of negative electrode sheets C11 ) is good or not based on the calculated third magnetic field.

[0073] Specifically, in step S4, the processing unit 24 determines whether the contact of the connection part is good based on the magnitude (absolute value) of the third magnetic field and the predetermined threshold value (value greater than 0) pre-stored in the storage unit 23. Then, when the magnitude of the third magnetic field is greater than the predetermined threshold value (in the case of "yes"), the processing unit 24 determines that the connection of the connection part is poor, and proceeds to step S5. On the other hand, when the magnitude of the third magnetic field is less than the predetermined threshold value (in the case of "no"), the processing unit 24 determines that the connection of the connection part is good, notifies the display unit 25 of the determined good connection part, and proceeds to step S7. Thus, by using the magnetic field caused by the current flowing only in the winding direction of the wound battery A to determine whether the connection of the connection part is good, it is possible to detect whether the connection of the connection part is good with high accuracy without relying on the measurement of the resistance value of the wound battery A.

[0074] Next, in step S5, the processing unit 24 determines the poorly connected electrode patch based on the magnitude and direction of the third magnetic field. Then, the processing unit 24 outputs the determined poorly connected electrode patch to the display unit 25, and the process proceeds to step S6.

[0075] Specifically, in step S5, the processing unit 24 determines the poorly connected electrode sheet based on the magnitude of the third magnetic field, the direction of the third magnetic field (positive or negative), and the table pre-stored in the storage unit 23. More specifically, in step S5, the processing unit 24 determines the poorly connected electrode sheet that is consistent with both the magnitude of the third magnetic field and the direction of the third magnetic field from the table based on the magnitude of the third magnetic field, the direction of the third magnetic field, and the table. Thus, the poorly connected electrode sheet can be easily determined.

[0076] like Figure 5A and Figure 5B As shown, when the positive electrode sheet B11_6 located at the outermost peripheral side of the connection portion connecting the plurality of electrodes and the external electrode in the wound battery A is poorly connected, a relatively small current I1 flowing in the clockwise direction (inner winding direction) of the wound battery A is generated, and a relatively small magnetic flux φ1 (i.e., the third magnetic field) in the positive direction of the axis of the wound battery A caused by the current I1 is generated. It should be noted that, here, the positive direction of the axis refers to the direction from one end side of the wound battery A toward the other end side of the wound battery A, which is also simply referred to as the positive direction.

[0077] On the other hand, Fig. 6A and Figure 6B As shown, when a plurality of positive electrode sheets B11_4 to B11_6 located on the outer peripheral side of the connection portion where the plurality of electrode sheets are connected to the external electrode in the wound battery A are poorly connected, a current I2 that is larger than the current I1 flowing in the clockwise direction (inner winding direction) of the wound battery A will be generated, and a magnetic flux φ2 (i.e., a third magnetic field) that is larger than the magnetic flux φ1 in the positive direction of the axis of the wound battery A caused by the current I2 will be generated.

[0078] In addition, if Fig. 7A and Figure 7B As shown, when a poor connection occurs at the negative electrode sheet C11_1 located at the innermost peripheral side of the connection portion where multiple electrode sheets are connected to the external electrode in the wound battery A, a relatively small current I3 will be generated in the clockwise direction (inner winding direction) of the wound battery A, and a relatively small magnetic flux φ3 (i.e., the third magnetic field) will be generated in the positive direction of the wound battery A due to the current I3.

[0079] On the other hand, Fig. 8A and Figure 8BAs shown, when a poor connection occurs in a plurality of negative electrode sheets C11_1 to C11_3 located on the inner circumferential side of the connection portion where the plurality of electrode sheets are connected to the external electrode in the wound battery A, a current I4 that is larger than the current I3 flowing in the clockwise direction (inner winding direction) of the wound battery A will be generated, and a magnetic flux φ4 (i.e., a third magnetic field) that is larger than the magnetic flux φ3 in the positive direction of the wound battery A caused by the current I4 will be generated.

[0080] And, if FIG. 5A to FIG. 6B or 7A to 8B As shown, the larger the third magnetic field is, the closer the electrode piece determined as poorly connected by the processing unit 24 is to the external electrode. Thus, the position of the poorly connected electrode piece among the plurality of arranged electrode pieces can be roughly determined.

[0081] In addition, if FIG. 5A to FIG. 8B As shown, the processing unit 24 determines the positive and negative of the poorly connected electrode piece based on the direction of the third magnetic field. Thus, the positive and negative of the poorly connected electrode piece can be easily determined.

[0082] Next, in step S6, the display unit 25 displays the poorly connected electrode pad output from the processing unit 24, and the present process ends. Thus, the user can easily understand the occurrence of poor connection and the poorly connected electrode pad.

[0083] On the other hand, in step S7, the display unit 25 displays that the connection portion notified from the processing unit 24 is well connected, and ends the present process. Thus, the user can easily understand that the connection portion is well connected.

[0084] [Functions and Effects Achieved by the First Embodiment]

[0085] Next, main effects achieved by the first embodiment will be described.

[0086] The detection system 1 of the first embodiment is a detection system 1 for detecting whether the connection between the connection parts of multiple electrode sheets in the wound battery A and the external electrodes is good, and comprises: a power supply unit 22, which supplies power between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A; a detection unit 4, which detects the magnetic field caused by the power supply to the wound battery A; and a processing unit 24, which determines whether the connection of the connection part is good based on the size of the detected magnetic field.

[0087] The detection method of the first embodiment is a detection method for detecting whether the connection between the connecting parts of multiple electrode sheets in a wound battery A and the external electrode is good, comprising: a power supply step, supplying power between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A; a detection step, detecting the magnetic field caused by the power supply to the wound battery A; and a judgment step, judging whether the connection of the connecting part is good based on the size of the detected magnetic field.

[0088] According to these configurations, by supplying power between the positive electrode sheet B11 composed of a plurality of sheets of the wound battery A and the negative electrode sheet C11 composed of a plurality of sheets of the wound battery A, when a connection failure occurs at a connection portion where the plurality of electrode sheets in the wound battery A are connected to an external electrode, a current can be generated that flows in the winding direction of the wound battery A. Furthermore, by detecting the magnetic field generated by the current flowing in the winding direction of the wound battery A and using it to determine whether the connection at the connection portion is good, it is possible to detect whether the connection at the connection portion is good with high accuracy without relying on the measurement of the resistance value of the wound battery A.

[0089] In addition, in the first embodiment, the processing unit 24 determines that the connection of the connection part is good when the magnitude (absolute value) of the magnetic field is below a prescribed threshold value, and determines that the connection of the connection part is poor when the magnitude (absolute value) of the magnetic field is greater than the prescribed threshold value.

[0090] According to this configuration, by using a predetermined threshold value, it is possible to accurately detect whether the connection of the connection portion is good or not.

[0091] In addition, in the first embodiment, the power supply unit 22 supplies a direct current between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A, and the detection unit 4 has: a first detection sensor 41, which is arranged close to the wound battery A and detects the magnetic field; and a second detection sensor 42, which is arranged farther away from the wound battery A than the first detection sensor and detects the external magnetic field, and the processing unit 24 determines whether the connection of the connecting part is good based on the detected magnetic field and the external magnetic field.

[0092] According to this configuration, the influence of the external magnetic field on the determination of whether the connection is good or not can be eliminated, so whether the connection of the connection portion is good or not can be detected with higher accuracy.

[0093] In the first embodiment, the detection system 1 further includes a current wiring 3 composed of a four-terminal pair measurement structure wiring, a twisted wiring, a coaxial wiring, or a magnetic shielding wiring connecting the power supply unit 22 and the positive electrode sheet B11 or the negative electrode sheet C11.

[0094] According to this configuration, since the generation of an external magnetic field can be suppressed, whether or not the connection at the connection portion is good can be detected with higher accuracy.

[0095] Furthermore, in the first embodiment, the detection system 1 further includes a detection wiring 5 composed of a four-terminal pair measurement structure wiring, a twisted wiring, a coaxial wiring, or a magnetic shield wiring that connects the detection unit 4 and the processing unit 24 .

[0096] According to this configuration, since the device is less susceptible to the influence of the external magnetic field, it is possible to detect with higher accuracy whether the connection at the connection portion is good or not.

[0097] Furthermore, in the first embodiment, the detection unit 4 detects the magnetic field generated by the current flowing in the winding direction of the wound battery A.

[0098] According to this configuration, it is possible to suppress the generation of noise caused by an external magnetic field or the like and improve the detection accuracy, so it is possible to detect with higher accuracy whether the connection of the connection portion is good or not.

[0099] Furthermore, in the first embodiment, the processing unit 24 determines that when the magnitude of the detected magnetic field (magnetic field related parameter) is greater than a predetermined threshold value, the greater the magnetic field (magnetic field related parameter), the closer the poorly connected electrode piece is to the external electrode.

[0100] According to this configuration, the position of an electrode sheet having a poor connection among the plurality of arranged electrode sheets can be roughly identified.

[0101] In the first embodiment, when the magnitude of the detected magnetic field (magnetic field related parameter) is larger than a predetermined threshold, the processing unit 24 determines the positive and negative of the poorly connected electrode pad based on the direction of the magnetic field (magnetic field related parameter).

[0102] According to this configuration, the positive and negative poles of the electrode pad having a poor connection can be easily identified.

[0103] In addition, in the first embodiment, when the magnitude of the detected magnetic field (magnetic field associated parameter) is greater than a specified threshold, the processing unit 24 determines the electrode sheet with poor connection based on the magnitude of the magnetic field (magnetic field associated parameter) and the direction of the magnetic field (magnetic field associated parameter).

[0104] According to this configuration, an electrode pad having a poor connection can be easily identified.

[0105] Furthermore, in the first embodiment, the power supply unit 22 and the processing unit 24 are integrally formed.

[0106] According to this configuration, the entire detection system 1 can be simplified.

[0107] [Modification of the first embodiment]

[0108] Next, refer to Figures 9 to 11B A detection system 1 according to a modified example will be described.

[0109] Fig. 9 It is a schematic explanatory diagram showing each configuration of the detection system 1 according to a modified example. Fig. 10A 1 is a schematic development view showing a connection failure of a negative electrode tab C11_6 located on the outermost peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound battery A according to a modified example. Fig. 10B 1 is a schematic perspective view showing a connection failure of a negative electrode tab C11_6 located on the outermost peripheral side of a connection portion where a plurality of electrode tabs are connected to an external electrode in a wound battery A according to a modified example. Fig.11A It is a schematic development view showing a connection failure of a plurality of negative electrode sheets C11_4 to C11_6 located on the outermost peripheral side of a connection portion where a plurality of electrode sheets are connected to an external electrode in a wound type battery A of a modified example. Fig. 11B 1 is a schematic perspective view showing a poor connection of a plurality of negative electrode sheets C11_4 to C11_6 located on the outermost peripheral side of the connection portion where the plurality of electrode sheets are connected to the external electrode in a wound-type battery A of a modified example. Fig. 10A and Fig.11A As shown in FIG. 1 , as an example, the wound battery A to be inspected for good connection has six positive electrode sheets B11_1 to B11_6 and six negative electrode sheets C11_1 to C11_6 in order from the inner circumference to the outer circumference. Fig. 10A and Fig.11A As shown, arrows drawn on the positive electrode layer B and the negative electrode layer C indicate the direction of electrons. In the modification, the same points as those in the first embodiment are omitted, and the points different from the first embodiment are mainly described.

[0110] In the first embodiment described above, a power supply unit 22 for supplying current is connected between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A, but the present invention is not limited thereto. For example, a resistor 6 as a discharge unit for discharging the wound battery A may be connected (see Fig. 9 ).

[0111] In this case, by discharging the wound battery A, a current can be generated that flows in the winding direction of the wound battery A, similarly to the first embodiment described above. Also, similarly to the first embodiment described above, the detection unit 4 can detect a magnetic field generated by the current flowing in the winding direction of the wound battery A.

[0112] In the first embodiment, the detection unit 4 is composed of the first detection sensor 41 and the second detection sensor 42, but the present invention is not limited thereto. For example, the detection unit 4 may be composed of only the first detection sensor 41 or may be composed of a solenoid coil instead of a detection sensor.

[0113] In addition, in the first embodiment described above, the power supply unit 22 supplies a predetermined direct current to the wound battery A, but the present invention is not limited thereto. For example, the power supply unit 22 may supply an alternating current to the wound battery A. In this case, the processing unit 24 determines whether the connection of the connection portion is good or not based on the ratio of the magnetic field detected by the detection unit 4 to the alternating current generated by the power supply unit 22 and the table. In this case, the table is composed of a magnitude range of the ratio of the magnetic field to the alternating current, the direction of the magnetic field, and a plurality of poorly connected electrode sheets corresponding to the ratio of the magnetic field to the alternating current.

[0114] Furthermore, in this case, the detection unit 4 detects a magnetic field of the same frequency component as the alternating current supplied from the power supply unit 22. Then, the processing unit 24 determines whether the connection of the connection part is good based on the magnetic field of the frequency component. For example, the processing unit 24 includes a lock-in amplifier, and specifically, the noise of the magnetic field of the same frequency component as the alternating current is removed by the lock-in amplifier. Then, the processing unit 24 determines whether the connection of the connection part is good based on the magnetic field of the frequency component from which the noise is removed (the magnitude of the magnetic field of the frequency component and the direction of the magnetic field of the frequency component).

[0115] According to this variation, by supplying alternating current to the wound battery A instead of direct current, the generation of noise caused by external magnetic fields (such as the earth's magnetic field) can be suppressed compared to the case where direct current is supplied to the wound battery A, and the detection accuracy can be improved, thereby enabling the detection of whether the connection of the connection part is good with higher accuracy.

[0116] Furthermore, when the power supply unit 22 supplies an alternating current to the wound battery A sealed in the housing, the frequency of the alternating current is preferably 10 kHz or less. This is because if the alternating current is set to a high frequency, the magnetic field caused by the current flowing in the winding direction of the wound battery A may not be detected from the outside of the housing due to the magnetic shielding effect achieved by the housing.

[0117] In addition, in the first embodiment described above, the first external electrode D1 and the second external electrode D2 are respectively connected to the lower surface of the positive electrode sheet B11 located at the innermost circumference in the positive electrode sheet group B1 and the lower surface of the negative electrode sheet C11 located at the outermost circumference in the negative electrode sheet group C1. However, the first external electrode D1 and the second external electrode D2 are not limited thereto, and for example, they may also be respectively connected to the lower surface of the positive electrode sheet B11 located at the innermost circumference in the positive electrode sheet group B1 and the upper surface of the negative electrode sheet C11 located at the innermost circumference in the negative electrode sheet group C1 (see FIG. 10A to FIG. 11B ).

[0118] In this case, if Fig. 10A and Fig. 10B As shown, when a connection failure occurs in the negative electrode sheet C11_6 located at the outermost peripheral side of the connection portion where the plurality of electrodes are connected to the external electrode in the wound battery A of the modified example, a relatively small current I5 flowing in the counterclockwise direction (outer winding direction) of the wound battery A of the modified example is generated, and a relatively small magnetic flux φ5 (i.e., a third magnetic field) in the negative direction of the axis of the wound battery A of the modified example is generated by the current I5. Here, the negative direction of the axis is the direction from the other end side of the wound battery A toward the one end side of the wound battery A, and is also simply referred to as the negative direction.

[0119] On the other hand, Fig.11A and Fig. 11B As shown, when a plurality of negative electrode sheets C11_4 to C11_6 located on the peripheral side of the connection portion where the plurality of electrode sheets are connected to the external electrode in the wound battery A of the modified example are poorly connected, a current I6 that is larger than the current I5 flowing in the counterclockwise direction (outer winding direction) of the wound battery A of the modified example will be generated, and a magnetic flux φ6 (i.e., a third magnetic field) that is larger than the magnetic flux φ5 in the negative direction of the wound battery A of the modified example will be generated due to the current I6.

[0120] [Second Embodiment]

[0121] Below, refer to Fig.12 and Fig.13 A detection system 1 and a detection method according to a second embodiment will be described. It should be noted that in the second embodiment, points identical to those of the first embodiment will be omitted, and points different from the first embodiment will be mainly described.

[0122] [Composition of the detection system]

[0123] First, refer to Fig.12 A detection system according to the second embodiment will be described.

[0124] Fig.12 It is a schematic explanatory diagram showing each structure of the detection system 1 according to the second embodiment.

[0125] In the first embodiment described above, the detection system 1 includes the detection device 2, the current wiring 3, the detection unit 4 and the detection wiring 5. Fig.12As shown, in the second embodiment, the detection system 1 includes a vibration table 7 as an application mechanism in addition to the detection device 2, the current wiring 3, the detection unit 4 and the detection wiring 5. It should be noted that in the second embodiment, the application mechanism is composed of the vibration table 7, but it is not limited to this. The application mechanism may also be composed of a mechanism having a function of applying an impact to the wound battery A, for example.

[0126] like Fig.12 As shown in FIG. 1 , a wound battery A is fixed on the vibration table 7. Thus, the vibration table 7 can apply vibrations of a predetermined amplitude and a predetermined frequency to the wound battery A. Furthermore, the vibration table 7 is electrically connected to the detection device 2. Thus, the processing unit 24 (refer to FIG. 1 ) of the detection device 2 can be used to detect the wound battery A. Figure 3 ) controls the movement of the vibration table 7.

[0127] It should be noted that, in the second embodiment, the vibration table 7 is configured to be controlled by the processing unit 24 , but the present invention is not limited thereto, and the vibration table 7 may be configured to be controlled by, for example, a controller built into the vibration table 7 .

[0128] In the first embodiment described above, the storage unit 23 of the detection device 2 stores the prescribed DC current, the prescribed threshold value, and the table. In contrast, in the second embodiment, the storage unit 23 stores, in addition to the prescribed DC current, the first threshold value that is the same as the prescribed threshold value, and the table, a prescribed frequency for the operation of the vibration table 7, a normal waveform as a normal parameter for determining whether the connection is good or not by the processing unit 24, and the second threshold value (see Figure 3 ).

[0129] [Detection method implemented by the detection system]

[0130] Next, refer to Fig.13 A detection method implemented by the detection system 1 of the second embodiment will be described.

[0131] Fig.13 It is a flowchart showing each step of the detection method implemented by the detection system 1 of the second embodiment.

[0132] In the first embodiment described above, the detection method implemented by the detection system 1 includes steps S1 to S7. In contrast, Fig.13 As shown, in the second embodiment, the detection method includes steps S101 to S111. It should be noted that steps S101 to S103 and steps S109 to S111 in the second embodiment are respectively consistent with steps S1 to S3 and steps S5 to S7 in the first embodiment, so their descriptions are omitted.

[0133] like Fig.13As shown, in step S104, the processing unit 24 determines whether the magnitude (absolute value) of the third magnetic field is greater than the first threshold value (a value greater than 0) pre-stored in the storage unit 23. Then, when the magnitude of the third magnetic field is greater than the predetermined threshold value (in the case of "yes"), the processing unit 24 determines that the connection of the connection part is poor, and proceeds to step S109. On the other hand, when the magnitude of the third magnetic field is less than the first threshold value (in the case of "no"), the processing unit 24 proceeds to step S105.

[0134] Next, in step S105, the vibration table 7 applies vibrations having a predetermined frequency to the wound battery A. Specifically, in step S105, the processing unit 24 generates a control signal for vibrating the vibration table 7 and outputs it to the vibration table 7. Then, the vibration table 7 applies vibrations having a predetermined frequency to the wound battery A based on the control signal output from the processing unit 24, and the process proceeds to step S106.

[0135] Next, in step S106 , the first detection sensor 41 detects the vibration magnetic field as the second magnetic field-related parameter in a state where vibration is applied to the wound battery A. Then, the first detection sensor 41 outputs the detected vibration magnetic field to the processing unit 24 via the input interface 21 , and the process proceeds to step S107 .

[0136] Next, in step S107, the processing unit 24 obtains a magnetic field variation waveform as a magnetic field variation parameter based on the magnetic field during vibration output from the first detection sensor 41. Then, the processing unit 24 calculates the correlation between the obtained magnetic field variation waveform and the normal waveform pre-stored in the storage unit 23, and proceeds to step S108. It should be noted that the normal waveform is, for example, a waveform detected by the first detection sensor 41 during vibration when the connection of the connection part is good.

[0137] Next, in step S108 , the processing unit 24 determines whether the connection of the connection portion (specifically, the plurality of positive electrode tabs B11 and the plurality of negative electrode tabs C11 ) is good or not based on the correlation amount.

[0138] Specifically, in step S108, the processing unit 24 determines whether the contact of the connection part is good based on the correlation amount and the second threshold value (a value greater than 0) pre-stored in the storage unit 23. Then, when the correlation amount is less than the second threshold value (in the case of "yes"), the processing unit 24 determines that the connection of the connection part is poor, and proceeds to step S109. On the other hand, when the correlation amount is greater than the second threshold value (in the case of "no"), the processing unit 24 determines that the connection of the connection part is good, notifies the display unit 25 of the determined good connection part, and proceeds to step S111. As a result, even when the resistance value of the wound battery A is low, it is possible to detect whether the connection of the connection part is good with high accuracy, so that the detection accuracy of detecting whether the connection of the connection part is good can be further improved.

[0139] On the other hand, when entering step S109 from step S104, that is, when the processing unit 24 determines that the connection part is poor before applying vibration to the wound battery A, steps S105 to S108 (that is, vibration and other steps) can be skipped, thereby improving the detection accuracy of the detection system 1 while simplifying the operation of the detection system 1.

[0140] [Operation and Effects Achieved by the Second Embodiment]

[0141] Next, main effects achieved by the second embodiment will be described.

[0142] In the second embodiment, the detection system 1 includes a vibration table 7 for applying vibration to the wound battery A in addition to the power supply unit 22, the detection unit 4 and the processing unit 24. The detection unit 4 detects the magnetic field in a state where no vibration is applied to the wound battery A (a first magnetic field-related parameter) and the magnetic field during vibration in a state where vibration is applied to the wound battery A (a second magnetic field-related parameter). The processing unit 24 determines whether the connection of the connection part is good based on the detected magnetic field and the magnetic field during vibration.

[0143] According to this configuration, in addition to the magnetic field in a state where vibration is not applied to the wound type battery A, the magnetic field during vibration is also used to determine whether the connection of the connection portion is good or not. Therefore, even in a state where the resistance value of the wound type battery A is low, whether the connection of the connection portion is good or not can be detected with high accuracy. As a result, the accuracy of detecting whether the connection of the connection portion is good or not can be further improved.

[0144] In addition, in the second embodiment, the processing unit 24 obtains the magnetic field change waveform based on the magnetic field during vibration to calculate the correlation between the magnetic field change waveform and the normal waveform. When the magnitude (absolute value) of the magnetic field is below the first threshold and the correlation is above the second threshold, it is determined that the connection of the connection part is good. When the magnitude (absolute value) of the magnetic field is greater than the first threshold or the correlation is less than the second threshold, it is determined that the connection of the connection part is poor.

[0145] According to this configuration, by using both the first threshold value and the second threshold value, it is possible to detect more accurately whether the connection of the connection portion is good or not.

[0146] [Modification of the Second Embodiment]

[0147] Next, refer to Fig.14 A detection system 1 and a detection method according to a modified example of the second embodiment will be described. Note that, in this modified example, points identical to the second embodiment described above are omitted, and points different from the second embodiment described above are mainly described.

[0148] Fig.14 It is a flowchart showing each step of the detection method according to the modification example of the second embodiment.

[0149] In the second embodiment described above, the storage unit 23 stores a predetermined DC current, a single first threshold, a single predetermined frequency, a single second threshold, a single normal waveform, and a table. In contrast, in this variation, a predetermined DC current, a single first threshold, multiple frequencies that change in stages, multiple second thresholds, multiple normal waveforms, and a table are stored. It should be noted that multiple frequencies, multiple second thresholds, and multiple normal waveforms are associated with each other.

[0150] In the above-mentioned second embodiment, the detection method includes steps S101 to S111, whereas in this variant, it includes steps S201 to S212. It should be noted that steps S201 to S204 and steps S210 to S212 in this variant are respectively consistent with steps S101 to S104 and steps S109 to S111 in the second embodiment, and therefore their descriptions are omitted.

[0151] like Fig.14As shown, in step S205, the vibration table 7 applies vibrations having a specific frequency to the wound battery A. Specifically, in step S205, the processing unit 24 determines the frequency of the vibration table 7 (for example, first determines the frequency with the smallest frequency from a plurality of frequencies, and then switches to determine the frequency in descending order), generates a control signal for causing the vibration table 7 to vibrate at the determined frequency, and outputs it to the vibration table 7. Then, the vibration table 7 applies vibrations having the determined frequency to the wound battery A based on the control signal output from the processing unit 24, and the process proceeds to step S206.

[0152] Next, in step S206 , the first detection sensor 41 detects the vibration magnetic field when the vibration of the determined frequency is applied to the wound battery A. Then, the first detection sensor 41 outputs the detected vibration magnetic field to the processing unit 24 via the input interface 21 , and the process proceeds to step S107 .

[0153] Next, in step S207, the processing unit 24 obtains the magnetic field variation waveform based on the vibration magnetic field output from the first detection sensor 41. Then, the processing unit 24 calculates the correlation between the obtained magnetic field variation waveform and the normal waveform associated with the determined frequency, and proceeds to step S208.

[0154] Next, in step S208, the processing unit 24 determines whether the correlation amount is less than a second threshold value (a value greater than 0) associated with the determined frequency. Then, if the correlation amount is less than the second threshold value (in the case of "Yes"), the processing unit 24 determines that the connection of the connected part is poor, and proceeds to step S210. On the other hand, if the correlation amount is greater than the second threshold value (in the case of "No"), the process proceeds to step S209.

[0155] Next, in step S209, the processing unit 24 determines whether there is an undetermined frequency. Then, if there is an undetermined frequency (in the case of "Yes"), the process returns to step S205. On the other hand, if there is no undetermined frequency (in the case of "No"), the process proceeds to step S212.

[0156] That is, when the magnitude (absolute value) of the magnetic field is less than the first threshold value and the correlation amount is greater than the second threshold value in all frequencies, the processing unit 24 determines that the connection of the connection portion is good. On the contrary, when the correlation amount in any of the multiple frequencies is less than the second threshold value, the processing unit 24 determines that the connection of the connection portion is poor. As a result, the detection accuracy of whether the connection of the connection portion is good can be further improved compared to the case where the wound battery A is vibrated at a single frequency.

[0157] In this variation, the vibration table 7 applies variable frequency vibration to the wound battery A, and the processing unit 24 obtains the magnetic field variation waveform at each frequency based on the magnetic field during vibration (the second magnetic field associated parameter), calculates the correlation between the magnetic field variation waveform and the normal waveform at each frequency, and when the magnitude (absolute value) of the magnetic field is below the first threshold and the correlation is above the second threshold at all frequencies, the connection of the connection part is judged to be good.

[0158] According to this configuration, the accuracy of detecting whether the connection at the connection portion is good or not can be further improved compared to the case where the wound battery A is vibrated at a single frequency.

[0159] In the second embodiment described above, a power supply unit 22 for supplying current is connected between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A, but the present invention is not limited thereto. For example, a resistor 6 for discharging the wound battery A may be connected (see Fig. 9 ).

[0160] In addition, in the modified example of the second embodiment, multiple frequencies are changed in stages during vibration, but this is not limited to this, and for example, they may be changed randomly. In this case, the detection system 1 further includes a frequency detection unit (not shown) for detecting the frequency of vibration applied to the wound battery A. And the detection unit 4 detects the magnetic field according to each detected frequency.

[0161] [Third Embodiment]

[0162] Below, refer to Figures 15 to 19 , a detection system 1 and a detection method according to a third embodiment will be described. It should be noted that in the third embodiment, the same points as those in the first embodiment are omitted, and the differences from the first embodiment will be mainly described.

[0163] [Composition of the detection system]

[0164] First, refer to Figure 15 to Figure 16 , a detection system 1 according to a third embodiment will be described.

[0165] Fig.15 It is a schematic explanatory diagram showing each configuration of a detection system 1 according to a third embodiment. Fig.16 This is a schematic explanatory diagram showing an example of a plurality of detection locations according to the third embodiment.

[0166] In the first embodiment, the detection unit 4 is composed of the first detection sensor 41 and the second detection sensor 42. Fig.15 As shown, in the third embodiment, the detection unit 4 is composed of only the first detection sensor 41. In this case, Fig.15As shown by the arrows, for example, the first detection sensor 41 is moved while detecting the magnetic field at a plurality of detection locations ( Fig.16 ).

[0167] It should be noted that, in the third embodiment, Fig.16 As shown, a plurality of (i) detection sites (specifically, detection sites P1, P2, ..., Pi-1, Pi) are arranged at predetermined intervals (equal intervals) in the vertical direction in such a manner that they are located between (in the middle of) a plurality of positive electrode layers B and negative electrode layers C. However, the plurality of detection sites are not limited thereto, and for example, the plurality of detection sites may be arranged at intervals in the horizontal direction, or may be arranged at intervals in a direction inclined relative to the horizontal direction.

[0168] In addition, in the third embodiment, the first detection sensor 41 is composed of a single first detection sensor that detects the magnetic field while moving between multiple detection locations, but is not limited to this. The first detection sensor 41 may also be composed of multiple first detection sensors that are pre-set at multiple detection locations to detect the magnetic field.

[0169] Furthermore, in the first embodiment described above, the storage unit 23 of the detection device 2 stores the prescribed DC current, the prescribed threshold value, and the table. In contrast, in the third embodiment, the storage unit 23 stores, in addition to the prescribed DC current, the ideal characteristic curve M as an ideal characteristic parameter used in the determination process of whether the connection is good or not performed by the processing unit 24. ID (x) and an addition threshold as a consistency threshold. Here, the ideal characteristic curve M ID (x) represents the position information of multiple (i) detection parts (i.e., the distance between the reference position and the detection part) under an ideal state and multiple magnetic fields M as magnetic field association parameters respectively associated with the position information of the multiple (i) detection parts. ID (Specifically, the magnetic flux density) characteristic curve (refer to Fig.18 ), where x=1, 2, ..., i-1, i. It should be noted that in the third embodiment, the reference position is composed of the detection part P1 located at the bottom (refer to Fig.16 ), but is not limited to this, and the reference position may be composed of, for example, the detection part Pi located at the top.

[0170] [Detection method implemented by the detection system]

[0171] Next, refer to Figures 17 to 19 , a detection method implemented by the detection system 1 of the third embodiment is described.

[0172] Fig.17It is a flowchart showing each step of the detection method implemented by the detection system 1 of the third embodiment. Fig.18 It represents the ideal characteristic curve M ID (x), good product characteristic curve M OK (x) and defective product characteristic curve M NG (x) is a comparison curve of the three, where x = 1, 2, ..., i-1, i. It should be noted that Fig.18 In FIG. 1 , the position information (mm) of the detection part and the magnetic field M (specifically, the magnetic flux density / μT) are used as the horizontal axis and the vertical axis, respectively. Fig.19 1 is an explanatory diagram showing an example of calculation of the degree of coincidence, showing a good product characteristic curve M of a good product. OK (x) and the ideal characteristic curve M ID (x) is added to the absolute value of the difference ∑|M OK (x)-M ID (x)| and the defective product characteristic curve M of the defective product NG (x) and the ideal characteristic curve M ID (x) is added to the absolute value of the difference ∑|M NG (x)-M ID (x)|, where x = 1, 2, ..., i-1, i. It should be noted that Fig.19 In the graph, the magnetic field M (specifically, magnetic flux density / μT) is the vertical axis.

[0173] In the first embodiment described above, the detection method implemented by the detection system 1 includes steps S1 to S7. In contrast, Fig.17 As shown, in the third embodiment, the detection method includes steps S31 to S37. It should be noted that step S31 and step S37 in the third embodiment are respectively consistent with step S1 and step S7 in the first embodiment, so their descriptions are omitted.

[0174] like Fig.17 As shown, in step S32, the first detection sensor 41 detects the magnetic field caused by the current flowing in the winding direction of the wound battery A at multiple detection locations. Then, the first detection sensor 41 outputs the detected multiple magnetic fields to the processing unit 24 via the input interface 21, and the process proceeds to step S33.

[0175] Next, in step S33, the processing unit 24 generates a detection characteristic curve as a detection characteristic parameter based on the position information of multiple detection parts and multiple magnetic fields output from the first detection sensor 41 (specifically, multiple magnetic fields associated with the position information of multiple detection parts, respectively), and enters step S34.

[0176] Here, if Fig.18As shown, the detection characteristic curve diagram generated by the processing unit 24 includes a good product characteristic curve M OK (x) and defective product characteristic curve M NG (x) Both. It should be noted that the characteristic curve M of the good product OK (x) represents the position information of a plurality of (i) detection locations and a plurality of magnetic fields M associated with the position information of the plurality of (i) detection locations when the connection portion is well connected. OK Characteristic curve of defective product. NG (x) represents position information of a plurality of (i) detection locations and a plurality of magnetic fields M associated with the position information of the plurality of (i) detection locations when the connection of the connection portion is poorly connected. NG Characteristic curve of . Where x=1, 2, …, i-1, i.

[0177] Next, in step S34, the processing unit 24 performs a calculation based on the generated detection characteristic curve and the ideal characteristic curve M. ID (i) to calculate the consistency between the two (for example, the detection characteristic curve and the ideal characteristic curve M ID The absolute value addition operation of the difference (i) is also referred to as “absolute value addition operation of the difference” hereinafter), and the process proceeds to step S35.

[0178] Here, if Fig.19 As shown, the detection characteristic curve calculated by the processing unit 24 is consistent with the ideal characteristic curve M ID The addition operation of the absolute value of the difference of (x) includes: the good product characteristic curve M of the good product OK (x) and the ideal characteristic curve M ID (x) is added to the absolute value of the difference ∑|M OK (x)-M ID (x)| and the defective product characteristic curve M of the defective product NG (x) and the ideal characteristic curve M ID (x) is added to the absolute value of the difference ∑|M NG (x)-M ID (x)|, where x=1, 2, ..., i-1, i.

[0179] Next, in step S35 , the processing unit 24 determines whether the connection of the connected portion is good or not based on the difference absolute value addition and the addition threshold value stored in advance in the storage unit 23 .

[0180] Then, when the difference absolute value addition is greater than the addition threshold value (in the case of "Yes"), that is, when the degree of consistency is less than the degree of consistency threshold value, the processing unit 24 determines that the connection of the connection part is poor, and proceeds to step S36. On the other hand, when the difference absolute value addition is less than the addition threshold value (in the case of "No"), that is, when the degree of consistency is greater than the degree of consistency threshold value, the processing unit 24 determines that the connection of the connection part is poor, and proceeds to step S37.

[0181] Thus, the magnetic fields at the plurality of detection locations caused by the current flowing in the winding direction of the wound battery A are used to determine whether the connection of the connection portion is good or not. Therefore, even when the magnetic field generated by a defective connection portion is small, it is possible to detect whether the connection of the connection portion is good or not with high accuracy. As a result, the accuracy of detecting whether the connection of the connection portion is good or not can be further improved.

[0182] Next, in step S36 , the display unit 25 displays the connection failure of the electrode sheet output from the processing unit 24 , and ends the present process.

[0183] Furthermore, in the third embodiment described above, the degree of coincidence between the detected characteristic parameter and the ideal characteristic parameter is achieved by the above-described difference absolute value addition operation, but the present invention is not limited thereto and may be achieved by other operations or the like.

[0184] In the third embodiment, a power supply unit 22 for supplying current is connected between the positive electrode sheet B11 of the wound battery A and the negative electrode sheet C11 of the wound battery A. However, the present invention is not limited thereto. For example, a resistor 6 for discharging the wound battery A may be connected (see Fig. 9 ).

[0185] [Operation and Effects Achieved by the Third Embodiment]

[0186] Next, main effects achieved by the third embodiment will be described.

[0187] In the third embodiment, the detection unit 4 detects the magnetic field at multiple detection locations, and the processing unit 24 generates a detection characteristic curve based on the position information of the multiple detection locations and multiple magnetic field association parameters associated with the position information of the multiple detection locations, and calculates the detection characteristic curve and the ideal characteristic curve M. ID The absolute value addition of the difference of (x) determines whether the connection of the connected part is good or not based on the absolute value addition of the difference.

[0188] According to this configuration, the magnetic field at a plurality of detection locations caused by the current flowing in the winding direction of the wound battery A is used to determine whether the connection of the connection portion is good or not. Therefore, even when the magnetic field generated by a defective connection portion is small, it is possible to detect whether the connection of the connection portion is good or not with high accuracy. As a result, the accuracy of detecting whether the connection of the connection portion is good or not can be further improved.

[0189] In the third embodiment, the processing unit 24 determines that the connection of the connection part is good when the difference absolute value addition is below the addition threshold, and determines that the connection of the connection part is poor when the difference absolute value addition is greater than the addition threshold.

[0190] According to this configuration, by using the addition threshold value, it is possible to detect with high accuracy whether the connection of the connection portion is good or not.

[0191] This application claims priority based on Japanese Patent Application No. 2022-149275 filed with the Japan Patent Office on September 20, 2022, and priority based on Japanese Patent Application No. 2023-143973 filed with the Japan Patent Office on September 5, 2023, and all the contents of these applications are incorporated herein by reference.

[0192] Although the embodiments and modifications have been described above, the embodiments and modifications merely illustrate a part of application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific configurations of the embodiments.

[0193] Description of Reference Numerals

[0194] 1: Detection system;

[0195] 3: Current wiring;

[0196] 4: Detection department;

[0197] 5: Detect wiring;

[0198] 6: Resistance (discharge part);

[0199] 22: Power supply department;

[0200] 24: Processing Department;

[0201] 41: first detection unit;

[0202] 42: second detection unit;

[0203] A: Wound type battery;

[0204] B11: positive electrode;

[0205] C11: Negative electrode.

Claims

1. A detection system for detecting whether the connection between a plurality of electrode sheets in a wound battery and an external electrode is good, the detection system comprising: A power supply unit or a discharge unit for supplying power or discharging power between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery; a detection unit that detects a magnetic field-related parameter caused by power supply to the wound-type battery or discharge from the wound-type battery; and The processing unit determines whether the connection of the connection portion is good or not based on the detected magnetic field-related parameter.

2. The detection system according to claim 1, wherein: The processing unit determines that the connection of the connection portion is good when the absolute value of the magnetic field related parameter is less than a predetermined threshold value, and determines that the connection of the connection portion is poor when the absolute value of the magnetic field related parameter is greater than the predetermined threshold value.

3. The detection system according to claim 1, wherein: The power supply unit supplies a direct current between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery. The detection unit has: a first detection unit disposed close to the wound battery and detecting a magnetic field; and a second detection unit which is disposed farther from the wound battery than the first detection unit and detects an external magnetic field; The processing unit determines whether the connection of the connection portion is good or not based on the detected magnetic field and the external magnetic field.

4. The detection system according to claim 1, further comprising: The current wiring connects the power supply part or the discharge part with the positive electrode sheet or the negative electrode sheet, and the current wiring is composed of a four-terminal pair measurement structure wiring, a twisted wiring, a coaxial wiring or a magnetic shielding wiring.

5. The detection system according to claim 1, further comprising: The detection wiring connects the detection unit and the processing unit, and the detection wiring is composed of a four-terminal pair measurement structure wiring, a twisted wiring, a coaxial wiring, or a magnetic shielding wiring.

6. The detection system according to claim 1, wherein: The detection unit detects a magnetic field generated by a current flowing in a winding direction of the wound battery.

7. The detection system according to claim 1, wherein: When the power supply unit is connected between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery, The power supply unit supplies an alternating current between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery. The detection unit detects a magnetic field having the same frequency component as the alternating current, The processing unit determines whether the connection of the connection portion is good or not based on the magnetic field of the frequency component.

8. The detection system according to claim 1, wherein: The wound battery is sealed in a housing, When the power supply unit is connected between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery, The power supply unit supplies an alternating current between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery. The frequency of the alternating current is below 10 kHz.

9. The detection system according to claim 1, wherein: When the magnitude of the detected magnetic field-related parameter is greater than a predetermined threshold value, the larger the magnetic field-related parameter is, the closer the electrode piece determined by the processing unit as having a poor connection is to the external electrode.

10. The detection system according to claim 1, wherein: When the magnitude of the detected magnetic field-related parameter is greater than a predetermined threshold value, the processing unit specifies the positive and negative sides of the electrode sheet with poor connection based on the direction of the magnetic field-related parameter.

11. The detection system according to claim 1, wherein: When the detected magnitude of the magnetic field-related parameter is greater than a predetermined threshold value, the processing unit identifies the electrode sheet having a poor connection based on the magnitude of the magnetic field-related parameter and the direction of the magnetic field-related parameter.

12. The detection system according to claim 1, wherein: The power supply unit and the processing unit are formed integrally.

13. The detection system according to claim 1, further comprising: applying mechanism, applying vibration or impact to the wound battery, the detection unit detects a first magnetic field-related parameter which is the magnetic field-related parameter in a state where no vibration or impact is applied to the wound-type battery and a second magnetic field-related parameter which is the magnetic field-related parameter in a state where vibration or impact is applied to the wound-type battery, The processing unit determines whether the connection of the connection portion is good or not based on the detected first magnetic field related parameter and the second magnetic field related parameter.

14. The detection system according to claim 13, wherein: The processing unit performs the following actions: The magnetic field variation waveform is obtained based on the second magnetic field related parameter to calculate the correlation between the magnetic field variation waveform and the normal waveform. When the absolute value of the magnetic field correlation parameter is less than or equal to a first threshold value and the correlation amount is greater than or equal to a second threshold value, the connection of the connection portion is determined to be good. When the absolute value of the first magnetic field-related parameter is greater than a first threshold value, or when the correlation amount is less than a second threshold value, the connection of the connection portion is determined to be defective.

15. The detection system according to claim 13, wherein: The applying mechanism applies variable frequency vibration to the wound battery. The processing unit performs the following actions: Based on the second magnetic field associated parameter, a magnetic field variation parameter is obtained at each frequency, and a correlation between the magnetic field variation parameter and a normal parameter is calculated at each frequency. When the absolute value of the first magnetic field-related parameter is equal to or less than a first threshold value and the correlation amount is equal to or greater than a second threshold value in all frequencies, the connection of the connection portion is determined to be good.

16. The detection system according to claim 15, further comprising: a frequency detection unit that detects the frequency of the vibration applied to the wound type battery, The detection unit detects the second magnetic field-related parameter for each detected frequency.

17. The detection system according to claim 1, wherein: The detection unit detects the magnetic field related parameter at a plurality of detection locations, The processing unit performs the following actions: Based on the position information of the plurality of detection parts and the plurality of magnetic field associated parameters respectively associated with the position information of the plurality of detection parts, a detection characteristic parameter is generated, and the consistency between the detection characteristic parameter and the ideal characteristic parameter is calculated. Whether the connection of the connection portion is good or not is determined based on the degree of coincidence.

18. The detection system according to claim 17, wherein: The processing unit determines that the connection of the connection portion is good when the degree of match is equal to or greater than a degree of match threshold, and determines that the connection of the connection portion is poor when the degree of match is less than the degree of match threshold.

19. A detection method for detecting whether the connection between a plurality of electrode sheets in a wound-type battery and a connection portion of an external electrode is good, the detection method comprising: A power supply or discharge step, performing power supply or discharge between the positive electrode sheet of the wound battery and the negative electrode sheet of the wound battery; a detection step of detecting a magnetic field-related parameter caused by power supply to or discharge from the wound-type battery; and The step of determining whether the connection of the connection portion is good or not is based on the detected magnetic field related parameter.

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