JP6358920B2 - Contact state determination device, secondary battery inspection device, and contact state determination method - Google Patents

Description

  The present invention relates to an exterior member formed by molding a laminate film in which a synthetic resin layer is bonded to both surfaces of a metal layer into a bag shape or a cup shape, an electrode group and an electrolyte housed in the exterior member, and an exterior member Battery voltage for a capacitive object to be measured such as a secondary battery having one end projecting from each other and the other end in the exterior member connected to the positive electrode and the negative electrode of the electrode group. Contact state discriminating device and contact state discriminating method for discriminating the contact state between a pair of probes of a measuring device for measuring the measured amount of the electrode and the electrode to be measured, and inspection of a secondary battery provided with the contact state discriminating device It relates to the device.

  As this type of secondary battery inspection method, a secondary battery inspection method disclosed in Patent Document 1 below is known. In this secondary battery inspection method, a laminate film in which at least a heat-sealable resin layer, a metal layer made of aluminum or an aluminum alloy, and a synthetic resin layer are laminated in this order is formed into a bag shape, and the heat-sealability at the periphery of the opening An exterior member in which the resin layers are heat-sealed to form a heat seal portion, a positive electrode housed in the exterior member, an electrode group having a negative electrode and a separator and a non-aqueous electrolyte, and a positive electrode led out from the exterior member And a negative electrode terminal connected to the negative electrode and having a voltage of 3.75V to 3.90V.

  In this secondary battery, pinholes or the like may exist in the resin layer on the inner surface of the laminate film. In this case, lithium ions in the electrolyte react with the aluminum or aluminum alloy in the metal layer to cause a lithium-aluminum alloy. Is generated. This lithium-aluminum alloy has a large volume expansion and high reactivity with moisture. For this reason, the malfunction that a barrier property with respect to the water | moisture content etc. which is the original objective falls by time will generate | occur | produce in a secondary battery.

  Therefore, in the secondary battery inspection method disclosed in Patent Document 1, the voltage between the positive electrode terminal of the nonaqueous electrolyte secondary battery and the metal layer located in the heat seal portion of the exterior member is set to an input impedance of 1 G ohm or more. In this case, the presence or absence of the above-described defect is inspected by determining whether the voltage range of 0.2V to 3.1V is a determination index. In measuring the voltage between the positive electrode terminal and the metal layer of the exterior member, for example, one of the pair of measurement terminals is brought into contact with the positive electrode terminal, and the other measurement terminal has the tip of the exterior member. The synthetic resin layer located in the seal portion is penetrated to contact the metal layer.

  Further, in this secondary battery inspection method, although a voltmeter having an input impedance of 1 G ohm or more is used, the contact resistance between one measurement terminal and the positive terminal, and the other measurement terminal and the exterior member When the contact resistance with the metal layer is large (generally, the latter resistance value is likely to increase), the measurement error for the voltage of the secondary battery increases. For this reason, in this secondary battery inspection method, prior to voltage measurement with a voltmeter, the tip of the auxiliary measurement terminal penetrates the synthetic resin layer located at the seal portion of the exterior member and pierces the metal layer, The resistance between the measurement terminal and the auxiliary measurement terminal is measured to check the continuity between the other measurement terminal and the metal layer. Thereby, voltage measurement can be performed in a state in which the other measurement terminal is reliably in contact with the metal layer of the exterior member in a state where the contact resistance is small, and the reliability of the inspection is improved.

  By the way, in said structure using the auxiliary | assistant measurement terminal, since this auxiliary | assistant measurement terminal is provided in addition to a pair of measurement terminal, an apparatus structure becomes complicated so much. For this reason, it is preferable that the auxiliary measurement terminal is not used. As a configuration similar to the configuration for confirming the contact state between the pair of measurement terminals and the pair of terminals to be measured without using such auxiliary measurement terminals, the applicant of the present application The configuration disclosed in Document 2 has already been proposed. This configuration is for contact check, and includes a current source that supplies an AC constant current to the measurement target (sample to be measured), and an AC that detects an AC voltage generated at the measurement target when the AC constant current is supplied. An output amplifier and a second lock-in amplifier that synchronously detects an output signal of the AC output amplifier at a frequency of an AC constant current, and detecting contact resistance based on a voltage output from the second lock-in amplifier Is possible.

Japanese Patent Laying-Open No. 2005-251685 (page 3-9, FIG. 3) JP 2006-322821 A (pages 8-9, FIG. 4)

  However, the above-described configuration for confirming the contact state (configuration for contact check) has the following problems to be improved. That is, in the configuration for confirming the contact state, when the capacitance (capacitance) between the pair of probes connecting the measuring apparatus and the object to be measured is extremely small or negligible, the contact resistance is almost reduced. Although it is possible to detect accurately, under the situation where the capacitance between a pair of probes cannot be ignored, even if the contact resistance is large, the voltage output from the second lock-in amplifier is affected by the capacitance between the probes. descend. Therefore, the configuration for confirming the contact state accurately detects the contact state between the pair of measurement terminals and the pair of terminals to be measured in a situation where the capacitance between the pair of probes cannot be ignored. There is an issue that needs to be improved that there are cases where it cannot be done.

  The present invention has been made in order to improve such a problem, and without using an auxiliary measurement terminal, each of the objects to be measured of the pair of probes can be obtained even in a situation where the capacity between the pair of probes cannot be ignored. A contact state discriminating apparatus and a contact state discriminating method capable of accurately discriminating the contact state with the electrode, and a secondary battery capable of accurately executing the inspection of the secondary battery to be measured with the contact state discriminating apparatus. The main purpose is to provide an inspection device.

  The contact state determination device according to claim 1 is a contact state determination device that determines a contact state between a pair of probes that are brought into contact with a pair of electrodes to be measured. A pair of current output terminals connected to the pair of probes and supplying an AC test current to the object to be measured via the pair of probes; and a pair of voltage input terminals A voltage detection unit that is connected to each probe and detects an AC voltage generated between the pair of probes in the supply state of the AC inspection current as a detection voltage signal; and has the same frequency as the AC inspection current, and the AC inspection A detection signal generation unit that generates a detection signal delayed by an arbitrary angle within an angle range of greater than 0 degrees and less than 90 degrees with respect to the current; and the detected voltage signal It includes a detection unit for generating a DC detection voltage by detecting in use signal, and a processing unit for executing the contact determination process for determining the contact state based on the DC detection voltage.

  The contact state determination device according to claim 2 is the contact state determination device according to claim 1, wherein the processing unit is any one of an open state and a state that is very close to the open state in the contact determination process. Less than the impedance value between the pair of probes calculated in advance based on the AC inspection current and the DC detection voltage in the first contact state, and the contact state is a short-circuit state and a short-circuit state. A value that exceeds the impedance value between the pair of probes calculated in advance based on the alternating current inspection current and the direct current detection voltage in the second contact state that is one of the states that are very close to the state. Based on a predetermined threshold value and the AC inspection current and the DC detection voltage when the pair of probes are in contact with the pair of electrodes. Comparing the calculated impedance value between the pair of probes, when the impedance value is less than or equal to the threshold value, the contact state is good, and when the impedance value exceeds the threshold value The contact state is determined to be defective.

  The contact state determination device according to claim 3 is the contact state determination device according to claim 1, wherein in the contact determination process, the processing unit is any one of an open state and a state very close to the open state. A state that is lower than the voltage value of the DC detection voltage generated by the detection unit in the first contact state, and the contact state is very short and short. A threshold value that is defined in advance to a value that exceeds the voltage value of the DC detection voltage generated by the detection unit in the second contact state, and the pair of probes are in contact with the pair of electrodes. When the voltage value of the DC detection voltage is equal to or lower than the threshold value, the contact state is good, and the voltage of the DC detection voltage is There it is determined that when the value rises above this threshold the contact state is not normal.

  The inspection apparatus for a secondary battery according to claim 4 is a contact state determination device according to any one of claims 1 to 3, the pair of probes, and a pair of measurement terminals to which the pair of probes are respectively connected. A pair of voltage measurement terminals connected to the pair of measurement terminals, respectively, and a voltage measurement unit that measures a DC voltage generated between the pair of electrodes of the secondary battery as the measurement target. .

  The contact state determination method according to claim 5 is a contact state determination method for determining a contact state between a pair of probes brought into contact with a pair of electrodes to be measured, and the pair of currents. An output terminal is connected to each of the pair of probes, and a current supply step for supplying an AC inspection current to the object to be measured via the pair of probes; and a pair of voltage input terminals are connected to the pair of probes, respectively. A voltage detection step of detecting an alternating voltage generated between the pair of probes in the supply state of the alternating current inspection current as a detection voltage signal; and a frequency that is the same as the alternating current inspection current and having a phase relative to the alternating current inspection current. A detection signal generating step for generating a detection signal delayed by an arbitrary angle within an angle range of more than 0 degrees and less than 90 degrees; and the detection voltage signal is converted into the detection signal Performing a detection step of generating a DC detection voltage by detecting the signal, and a contact determination step of determining the contact state based on the DC detection voltage.

  The contact state determination method according to claim 6 is the contact determination step of the contact state determination method according to claim 5, wherein the contact state is one of an open state and a state very close to the open state. The impedance is less than the impedance value between the pair of probes calculated in advance based on the AC inspection current and the DC detection voltage in a single contact state, and the contact state is very close to the short circuit state and the short circuit state. It is preliminarily defined as a value that exceeds the impedance value between the pair of probes calculated in advance based on the AC inspection current and the DC detection voltage in the second contact state that is one of the states. The one calculated based on the threshold value and the AC inspection current and the DC detection voltage when the pair of probes are in contact with the pair of electrodes. When the impedance value is below the threshold value, the contact state is good, and when the impedance value exceeds the threshold value, the contact state is poor. It is determined that

  The contact state determination method according to claim 7 is a contact state determination method according to claim 5, wherein the contact state is one of an open state and a state that is extremely close to the open state. A second contact state that is lower than a voltage value of the DC detection voltage generated by the detection in the one contact state, and the contact state is one of a short circuit state and a state very close to the short circuit state. The DC detection generated when the pair of probes are brought into contact with the pair of electrodes, and a threshold value preliminarily defined to a value exceeding the voltage value of the DC detection voltage generated by the detection. When the voltage value of the DC detection voltage is less than or equal to the threshold value, the contact state is good, and the voltage value of the DC detection voltage exceeds the threshold value. Sometimes the contact state is determined to be defective.

  According to the contact state determination device according to claim 1 and the contact state determination method according to claim 5, each detection voltage signal is detected based on a DC detection voltage generated by detecting the detection voltage signal with a detection signal delayed by an arbitrary angle. By determining the contact state between the probe and each electrode to be measured, the auxiliary measurement terminal can be connected even if there is a capacitance that cannot be ignored between the pair of probes. Without using, it is possible to accurately determine the contact state between each probe and each electrode to be measured.

  The contact state determination apparatus according to claim 2 and the contact state determination method according to claim 6, wherein the DC detection voltage generated when the contact state between each probe and each electrode to be measured is the first contact state. The threshold value is preliminarily defined to an arbitrary value that is lower than the impedance value calculated based on the voltage and exceeds the impedance value calculated based on the DC detection voltage generated when the contact state is the second contact state. Has been.

  The contact state determination device according to claim 3 and the contact state determination method according to claim 7, wherein the DC detection voltage generated when the contact state between each probe and each electrode to be measured is the first contact state. The threshold value is defined in advance to an arbitrary value that is lower than the voltage value of the DC detection voltage and exceeds the voltage value of the DC detection voltage generated when the contact state is the second contact state.

  Therefore, according to these contact state determination devices and these contact state determination methods, based on the threshold value thus defined and the DC detection voltage generated when each probe is in contact with each electrode. By comparing the impedance value (or the voltage value of the DC detection voltage) calculated in this way, the quality of the contact state between each probe and each electrode to be measured can be reliably determined.

  Further, according to the secondary battery inspection apparatus of the fourth aspect, the contact state between each probe and each electrode of the secondary battery as the object to be measured is reliably made good by the contact state determination device. Since the battery voltage of the secondary battery can be measured by the voltage measurement unit in the state, the voltage measurement unit can accurately measure the battery voltage, and as a result, the quality of the secondary battery can be accurately inspected based on this accurate battery voltage. Can do.

It is a block diagram of the contact state determination apparatus 1 and the inspection apparatus 11 of a secondary battery. 4 is an equivalent circuit for a pair of measurement terminals TP1 and TP2, a pair of probes PL1 and PL2, and a secondary battery 70. Impedance (| Z when contact resistance Rc is changed from 1Ω to 1MΩ for each angle θ (0 °, −5 °, −10 °, −20 °, −40 °, −60 °, −90 °) | × cos θ) is a characteristic diagram. FIG. 4 is a characteristic diagram obtained by normalizing the value of the impedance (| Z | × cos θ) for each angle θ in FIG. 3 as “100%” when the contact resistance Rc is 1 MΩ.

  Hereinafter, embodiments of a contact state determination device, a secondary battery inspection device, and a contact state determination method will be described with reference to the accompanying drawings.

  First, each configuration of the contact state determination device and the secondary battery inspection device will be described with reference to the drawings.

  First, the configuration of the contact state determination device 1 as the contact state determination device shown in FIG. 1 will be described. The contact state discriminating apparatus 1 has a pair of electrodes EL1, EL2 (a secondary battery as an example in this example) whose tip side is a measurement object 70 (in this example, a secondary battery; hereinafter also referred to as a secondary battery 70). A pair of probes PL1 and PL2 that are brought into contact with a later-described positive electrode terminal 74 connected to a later-described positive electrode 72 and a metal layer 76a of an exterior member 71 described later (also referred to as a positive electrode terminal EL1 and a metal layer EL2). It is an apparatus which discriminate | determines the contact state between a pair of electrode EL1, EL2. As shown in FIG. 1, the base end of one probe PL1 of the pair of probes PL1 and PL2 is one measurement terminal TP1 of a pair of measurement terminals TP1 and TP2 of the inspection apparatus 11 described later. The base end of the other probe PL2 is connected to the other measurement terminal TP2.

  As shown in FIG. 1, as an example, the secondary battery 70 whose contact state with the pair of probes PL1 and PL2 is determined by the contact state determination device 1 includes an exterior member 71, electrode groups 72 and 73, and an electrolyte (not shown). The positive terminal 74 and the negative terminal 75 are provided. In this case, the exterior member 71 is configured by molding a laminate film 76 in which a synthetic resin layer (for example, polyethylene) 76b is bonded to both surfaces of a metal layer (sealant) 76a into a bag shape or a cup shape. The electrode groups 72 and 73 and the electrolyte are housed in the exterior member 71. The positive electrode terminal 74 is connected to the positive electrode 72 of the electrode groups 72 and 73, and the negative electrode terminal 75 is connected to the negative electrode 73 of the electrode groups 72 and 73.

  With the above configuration, the secondary battery 70 is configured such that when the positive electrode terminal 74 and the metal layer 76a become a pair of electrodes EL1 and EL2, the positive electrode terminal 74 and the metal layer 76a are coupled via the capacitance Cp. Therefore, it is a capacitive object to be measured. Note that the secondary battery 70 is also a capacitive measurement target even when the negative electrode terminal 75 and the metal layer 76a become a pair of electrodes EL1 and EL2.

  As shown in FIG. 1, the contact state determination device 1 includes, as an example, a current supply unit 2, a voltage detection unit 3, a detection signal generation unit 4, a detection unit 5, a processing unit 6, an output unit 7, and a storage unit 8. ing. The current supply unit 2 is composed of, for example, an AC constant current source (component having extremely high output impedance), and a pair of current output terminals 2a and 2b are connected to the base ends of the pair of probes PL1 and PL2 (each base end is connected). Are connected to a pair of measurement terminals TP1, TP2). With this configuration, the current supply unit 2 can supply an AC inspection current (AC constant current with a constant frequency f) I1 to the secondary battery 70 via the pair of probes PL1 and PL2. In the current supply unit 2, the current output terminal 2 b is connected to the reference potential (ground potential G) in the contact state determination device 1. Further, the current supply unit 2 outputs the reference signal Vref having the same frequency f and the same phase as the AC test current I1 to the detection signal generation unit 4 when the AC test current I1 is supplied.

  The voltage detection unit 3 is composed of, for example, an operational amplifier (not shown) configured in a voltage follower circuit, and a pair of probes to which a pair of voltage input terminals 3a and 3b are connected in the supply state of the AC inspection current I1. An AC voltage V1 generated between the base ends of PL1 and PL2 (a pair of measurement terminals TP1 and TP2 to which the base ends are connected) is detected with an extremely high input impedance, and a detection voltage signal V2 (in this example) As an example, an AC signal having the same amplitude as the AC voltage V1 is output with low impedance.

  The detection signal generation unit 4 receives the reference signal Vref, and has the same frequency f as the reference signal Vref, and an arbitrary phase within an angle range of more than 0 degrees and less than 90 degrees with respect to the reference signal Vref. Detection signal V3 delayed by an angle of (a detection signal V3 having a delay angle θ relative to the reference signal Vref, where angle θ is an arbitrary value within a range of 0 degree> θ> −90 degrees). Output. As described above, since the reference signal Vref has the same frequency and the same phase as the AC inspection current I1, the detection signal V3 has the same frequency as the AC inspection current I1 and is equal to the AC inspection current I1. It is also a signal delayed by an arbitrary angle within an angle range in which the phase exceeds 0 degree and less than 90 degrees (a signal in a range where the angle θ is less than 0 degree and exceeds −90 degrees).

  The detection unit 5 receives the detection voltage signal V2 and the detection signal V3, detects the detection voltage signal V2 with the detection signal V3 (synchronous detection), and generates and outputs a DC detection voltage V5. In this example, as an example, the detection unit 5 multiplies the detection voltage signal V2 and the detection signal V3 and outputs a multiplication signal V4, as shown in FIG. 1, and smoothes the multiplication signal V4. And a filter unit (low-pass filter) 5b for outputting the DC detection voltage V5.

  The DC detection voltage V5 will be specifically described. One detection voltage signal V2, which is the source of the DC detection voltage V5, that is, the AC voltage V1, is a voltage generated between the pair of measuring terminals TP1 and TP2 in the supply state of the AC inspection current I1, as described above. . Therefore, as shown in FIG. 1, when the impedance between the pair of measuring terminals TP1, TP2 in a state where the pair of probes PL1, PL2 is in contact with the pair of electrodes EL1, EL2 of the secondary battery 70 is Z. Furthermore, a voltage (| Z | × I1) generated in the impedance Z when the AC inspection current I1 flows through the impedance Z.

Note that the wiring capacitance (capacitance) between the pair of probes PL1 and PL2 connected to the pair of measurement terminals TP1 and TP2 is Cc, the contact resistance between the probe PL1 and the electrode EL1 is Rc1, and the probe PL2 and the electrode EL2 The contact resistance between them is assumed to be Rc2, and the secondary battery 70 is to be measured (capacitance Cp) to be measured in the configuration in which the positive electrode terminal 74 and the metal layer 76a are connected to the pair of electrodes EL1 and EL2. In consideration, an equivalent circuit from the pair of measurement terminals TP1 and TP2 to the secondary battery 70 has a configuration shown in FIG. Therefore, the impedance Z is the combined impedance of a circuit in which the capacitance Cc is connected in parallel to the series circuit of the two contact resistors Rc1 and Rc2 and the capacitance Cp (see the following formula (1)). .
Z = 1 / (1 / (Rc + 1 / jωCp) + jωCc) (1)
ω = 2πf and Rc = Rc1 + Rc2.

Here, when the alternating current inspection current I1 is an alternating current of a [A] (that is, a sine wave (a × sinωt) having an amplitude a), the alternating current voltage V1 generated when the alternating current inspection current I1 flows through the impedance Z ( In this example, the detection voltage signal V2) is | Z | × a × sin ωt. Therefore, if the reference signal Vref at this time is a sine wave (sin ωt), the detection signal V3 output from the detection signal generation unit 4 becomes sin (ωt + θ), and thus is output from the multiplication circuit 5a of the detection unit 5. The multiplication signal V4 is expressed as the following equation (2).
V4 = | Z | × a × sin ωt × sin (ωt + θ)
= | Z | × a × [cos θ−cos (2ωt + θ)] (2)

As a result, the DC detection voltage V5 output from the filter unit 5b of the detection unit 5 configured by a low-pass filter is a DC component of the multiplication signal V4 expressed by the above equation (2). ).
V5 = | Z | × a × cos θ (3)

  Based on this equation (3), when the contact resistance Rc, which is a parameter of | Z |, is changed from 1Ω to 1MΩ, the impedance calculated from the voltage value of the DC detection voltage V5 (the voltage of the DC detection voltage V5). A value obtained by dividing the value by the current value a of the AC inspection current I1 is a characteristic diagram showing | Z | × cos θ, for each angle θ (for example, 0 degrees, −5 degrees, −10 degrees, −20 degrees). -40 degrees, -60 degrees, -90 degrees), the result is as shown in FIG.

  Here, the state in which the contact resistance Rc is 1 MΩ means a state in which the contact resistance Rc is increased, which is one of a first contact state (open state (open state) and a state very close to the open state). Is an example of a case where the capacitance is substantially only the capacitance Cc). Further, the state in which the contact resistance Rc is 1Ω is the second contact state in which the contact resistance Rc is small (a short circuit state or a state extremely close to the short circuit state. The equivalent circuit in FIG. This is an example of a case where only a parallel circuit of Cc and capacitance Cp is provided. The capacitance Cc is set to 500 pF on the assumption that a 5 m coaxial cable (1.5D-2V) is used for the pair of probes PL1 and PL2, and the capacitance Cp of the secondary battery 70 is small lithium. Assuming an ion battery (for example, a laminate type lithium ion battery having an outer shape of 50 mm × 50 m, a relative dielectric constant of polyethylene of 2.3, and a sealant thickness of 50 μm), it is set to 2 nF. The frequency f of the AC inspection current I1 is 1 MHz.

  Further, in the characteristic diagram of the impedance (| Z | × cos θ) for each angle θ in FIG. 3, the value (reference value) when the contact resistance Rc is 1 MΩ is set to “100%”, and the impedance at each contact resistance Rc. FIG. 4 shows a characteristic diagram obtained by normalizing the values of.

  As is apparent from FIG. 4, an angle (angle θ, which is also a detection phase in the detection unit 5) to be delayed by the detection signal generation unit 4 is set to an arbitrary angle within an angle range of more than 0 degree and 90 degrees or less. In some cases, the contact resistance Rc is 1 MΩ (first contact state) as a reference value (100%), and the contact resistance at any angle θ (an angle less than 0 degree and greater than −90 degrees). The value in the second contact state where Rc becomes small converges to a convergence value for each angle θ (in this example, about 20% at any angle θ as an example). Therefore, an arbitrary impedance value (| Z | × cos θ) within the range exceeding the convergence value and below the reference value (100%) is calculated as an impedance value (| Z calculated based on the DC detection voltage V5). When the calculated impedance value (| Z | × cos θ) exceeds this threshold value by setting the threshold value for | × cos θ), the contact state is bad because the contact resistance Rc is large. When the determined impedance value (| Z | × cos θ) is less than or equal to this threshold value, it is possible to determine that the contact state is good because the contact resistance Rc is small.

  For example, in the example shown in FIG. 4, the convergence value is less than 25% even at an angle θ (θ = −5 degrees) at which the convergence value in the second contact state in which the contact resistance Rc is small is the largest. Set an arbitrary impedance value within a range greater than or equal to 100% and lower than 100% (for example, an impedance value at 40%) as a threshold value for the impedance calculated based on the DC detection voltage V5. Therefore, when the calculated impedance value exceeds the threshold value, the contact resistance Rc is large, so that the contact state is determined to be defective. When the calculated impedance value is equal to or lower than the threshold value, the contact state is determined. Since the resistance Rc is small, it can be determined that the contact state is good.

  However, as shown in FIG. 4, the normalized impedance is obtained when the angle θ is less than 0 degrees and any value within an angle range of −90 degrees or more (angle range including up to −90 degrees). In addition, as the contact resistance Rc increases from a small state, it increases from the respective convergence value toward the reference value (100%). However, the contact resistance Rc at which the increase starts increases as the angle θ decreases (the delay itself increases). That is, when the angle θ is −90 degrees, the contact resistance Rc that starts to increase is the largest, and as a result, it is determined that the contact state is good based on the threshold value defined as described above. The contact resistance Rc that can be increased.

  For example, in FIG. 4, when the threshold value is 80%, for example, when the angle θ is −5 degrees, the contact state is good when the contact resistance Rc is about 26Ω or less. In contrast, when the angle θ is −10 degrees, the angle θ is about 53Ω or less, when the angle θ is −20 degrees, the angle θ is about 110Ω or less, when the angle θ is −40 degrees, the angle θ is about 220Ω or less, and the angle θ is −60 degrees. The contact resistance Rc that can be determined to be good is about 370Ω or less and the angle θ is about 700Ω or less when the angle θ is −90 degrees, and the contact resistance Rc increases as the angle θ decreases (from 0 degrees to −90 degrees). Therefore, when the angle θ is −90 degrees, the contact resistance Rc becomes extremely large (detection sensitivity is deteriorated), which is not preferable. Therefore, the angle θ in the detection signal generation unit 4 needs to be an angle larger than −90 degrees (an angle closer to 0 degrees than −90 degrees, −80 degrees, −70 degrees, etc.).

  Thereby, in this contact state discrimination device 1, the angle delayed in the detection signal generation unit 4 is any value within the angle range of more than 0 degrees and less than 90 degrees (the angle θ is less than 0 degrees and −90). Any value within an angular range exceeding 50 degrees), and the impedance value (| Z | × cos θ) when the contact resistance Rc is 1 MΩ (first contact state) at this time is the reference value (100%) An arbitrary impedance value (| Z | × cos θ) that is lower than the reference value in the first contact state and exceeds the value in the second contact state (a value of about 20% in this example). The threshold value Dth indicating this threshold value is stored in advance in the storage unit 8 as will be described later.

  When the AC inspection current I1 supplied to the secondary battery 70 is a constant current as in the contact state determination device 1 of this example, the voltage value of the DC detection voltage V5 is proportional to the impedance (| Z | × cos θ). Therefore, it is possible to determine the magnitude of the contact resistance Rc, that is, whether the contact state is good or bad by setting a threshold value for the voltage value of the DC detection voltage V5. When this configuration is adopted, the angle delayed by the detection signal generation unit 4 is set to any value (arbitrary value) within an angle range of more than 0 degrees and less than 90 degrees. At this time, the contact resistance Rc is set to 1 MΩ (first value). The voltage value of the DC detection voltage V5 in the first contact state) is set as a reference value (100%), which is lower than the reference value in the first contact state and the value in the second contact state described above (above An arbitrary value (voltage value of the DC detection voltage V5) exceeding the convergence value) is calculated in advance as a threshold value, and threshold value data Dth indicating this threshold value is stored in the storage unit 8 in advance. .

  As apparent from the tendency shown in FIG. 3, when the angle θ in the detection signal generation unit 4 is changed from −5 degrees to a value closer to 0 degrees, the contact resistance Rc is set to 1 MΩ (first contact state). In this case, the impedance value (| Z | × cos θ) further decreases as indicated by an arrow in FIG. For this reason, for the same reason as when the angle θ is set to 0 degree, it may be difficult to accurately detect the contact state between the pair of probes PL1 and PL2 and the pair of electrodes EL1 and EL2. Further, as described above, when the angle θ is close to −90 degrees, the detectable contact resistance Rc increases. Therefore, the angle θ is preferably in the range of −5 degrees or more and −70 degrees or less.

  As an example, the processing unit 6 includes an A / D converter, a CPU, and a memory (all not shown), and functions as a part of the contact state determination device 1 and a part of the inspection device 11. Also works. In this case, when the processing unit 6 functions as a part of the contact state determination device 1 and executes the contact determination process, the A / D converter outputs the DC detection voltage V5 output from the detection unit 5 to the first. This is converted into voltage data (data indicating the voltage value of the DC detection voltage V5), and the CPU detects the first voltage data (voltage value of the DC detection voltage V5 indicated by the first voltage data) and the known current of the AC inspection current I1. An impedance calculation process for calculating an impedance based on the value is executed, and the calculated impedance is compared with threshold data Dth (described later) stored in the storage unit 8 to compare the pair of probes PL1 and PL2. The contact state between the pair of electrodes EL1, EL2 is determined.

  On the other hand, when the processing unit 6 functions as a part of the inspection device 11 and executes the inspection process, the second voltage data Dv indicating the voltage value of the battery voltage Vbat output from the voltage measurement unit 12 described later is used. The quality of the secondary battery 70 is inspected by comparing with voltage range data Dra described later stored in the storage unit 8.

  Here, the voltage range data Dra will be described. As disclosed in Patent Document 1 described above, which electrode of each electrode (the positive electrode terminal 74, the negative electrode terminal 75, and the metal layer 76a) of the secondary battery 70 is described. Includes a voltage generated between the pair of electrodes EL1 and EL2 when the secondary battery 70 is in a good state (normal state) depending on whether the pair of electrodes EL1 and EL2 is an electrode (the electrode that contacts the pair of probes PL1 and PL2). Voltage range (voltage range serving as a pass / fail judgment index) is uniquely determined. Therefore, for example, for the secondary battery 70 to be inspected, this voltage range is obtained in advance by experiments or the like, and data indicating this voltage range is stored in the storage unit 8 as the voltage range data Dra.

  In addition, the processing unit 6 causes the output unit 7 to output the determination result in the contact determination process and the result of the inspection process by executing the output process. In this example, the output unit 7 is configured by a display device such as a display device, functions as a part of the contact state determination device 1, displays the determination result in the contact determination processing on the screen, and also inspects the inspection device. 11 also functions as a part of 11 and displays the result of the inspection process on the screen. Note that the output unit 7 may be configured by an external interface circuit instead of the display device. In this configuration, the output unit 7 outputs the results of the above processes to the external device via the external interface circuit.

  The storage unit 8 is composed of, for example, a semiconductor memory or a hard disk device, and functions as a part of the contact state determination device 1 and also functions as a part of the inspection device 11. The storage unit 8 defines an operation program for the processing unit 6, threshold value data Dth indicating a threshold value used in the contact determination process, and a non-defective voltage range used in the inspection process. Voltage range data Dra is stored in advance.

  Next, the configuration of the inspection apparatus 11 as the secondary battery inspection apparatus shown in FIG. 1 will be described. The inspection device 11 includes a contact state determination device 1, a pair of measurement terminals TP1 and TP2, a pair of probes PL1 and PL2, a voltage measurement unit 12, a processing unit 6, an output unit 7, and a storage unit 8, and includes a secondary battery. The battery voltage Vbat generated between the pair of electrodes EL1, EL2 is measured, and the secondary battery 70 can be inspected based on the measured battery voltage Vbat. Note that the description of the configuration (the processing unit 6, the output unit 7, and the storage unit 8) shared with the above-described contact state determination device 1 is omitted because it has already been described in the description of the configuration of the contact state determination device 1.

  The voltage measuring unit 12 is composed of a voltage measuring device having an extremely high input resistance Rin such as a digital multimeter, for example, and each base end of the pair of probes PL1 and PL2 (a pair of measurements to which the base ends are connected) DC voltage (battery voltage Vbat in this example) input between the pair of voltage input terminals 12a and 12b connected to the terminals TP1 and TP2) is accurately (when the contact state of the probes PL1 and PL2 is normal). Measurement is performed (without being influenced by the contact resistance Rc), and voltage data Dv indicating the voltage value of the battery voltage Vbat is output to the processing unit 6.

  Note that the voltage measuring unit 12 may have the same configuration as that of the voltage detecting unit 3 instead of the configuration of outputting the voltage data Dv indicating the voltage value of the battery voltage Vbat such as a digital multimeter. When this configuration is adopted, the voltage measuring unit 12 detects the battery voltage Vbat with an extremely high input impedance and outputs it as a voltage signal. Therefore, in this case, when the processing unit 6 functions as a part of the inspection device 11 and executes the inspection process, the A / D converter outputs the voltage signal output from the voltage measurement unit 12. The voltage data (second voltage data Dv indicating the voltage value of the battery voltage Vbat) is converted, and the quality of the secondary battery 70 is inspected based on the voltage data.

  Next, the operation of the contact state determination device 1 will be described together with the contact state determination method, and the operation of the inspection device 11 will also be described. It is assumed that the probe PL1 is in contact with the positive electrode terminal 74 serving as the electrode EL1 of the secondary battery 70, and the probe PL2 is in contact with the metal layer 76a serving as the electrode EL2 of the secondary battery 70.

  In the inspection device 11, first, the contact state determination device 1 operates to determine the contact state between the probe PL1 and the positive electrode terminal 74 and between the probe PL2 and the metal layer 76a.

  Specifically, in the contact state determination device 1, the current supply unit 2 supplies the AC inspection current I1 to the secondary battery 70 (current supply step) and also supplies the reference signal Vref to the detection signal generation unit 4. Execute the output. Further, the voltage detector 3 detects the AC voltage V1 generated between the pair of measurement terminals TP1 and TP2 in the supply state of the AC inspection current I1, and outputs it as a detection voltage signal V2 (voltage detection step). Further, the detection signal generation unit 4 has the same frequency as the input reference signal Vref, and the phase is delayed by an arbitrary angle within an angle range of more than 0 degrees and less than 90 degrees with respect to the reference signal Vref. A detection signal V3 (detection signal V3 having an arbitrary angle within an angle range in which the angle θ is less than 0 degree and greater than −90 degrees) is generated and output (detection signal generation step).

  The detection unit 5 receives the detection voltage signal V2 and the detection signal V3, and detects (synchronous detection) the detection voltage signal V2 with the detection signal V3, thereby generating a DC detection voltage V5 and processing unit. 6 (detection step).

  Moreover, the process part 6 functions as a part of contact state determination apparatus 1, and performs a contact determination process (contact determination step). In the contact determination process, the processing unit 6 first converts the DC detection voltage V5 into first voltage data, and the first voltage data (the voltage value of the DC detection voltage V5 indicated by the first voltage data) and the AC inspection. The impedance is calculated based on the known current value of the current I1. Next, the processing unit 6 reads the threshold data Dth stored in the storage unit 8 and compares it with the calculated impedance. As a result of this comparison, when the calculated impedance exceeds the threshold value indicated by the threshold value data Dth, the processing unit 6 determines that the contact state is defective because the contact resistance Rc is large, and is calculated. When the impedance is less than or equal to this threshold value, it is determined that the contact state is good because the contact resistance Rc is small. Thereby, the contact determination process is completed, and thereafter the processing unit 6 causes the output unit 7 to output the determination result of the contact determination process by executing the output process.

  Since the discrimination result in the contact discrimination process is output to the output unit 7 in this way, the user of the inspection apparatus 11 is required to generate a capacitance Cc that cannot be ignored between the coaxial cables. Even when the pair of probes PL1 and PL2 is formed of such a material, based on the determination result output to the output unit 7, between the probe PL1 and the positive terminal 74, and between the probe PL2 and the metal layer 76a. It is possible to accurately grasp the contact state. Therefore, when the user grasps that the contact state of the probes PL1 and PL2 is poor, the user recontacts the probe PL1 with the positive electrode terminal 74 until the determination result output to the output unit 7 becomes good. At the same time, by bringing the probe PL2 into contact with the metal layer 76a again, the probes PL1 and PL2 can be reliably brought into contact with the positive electrode terminal 74 and the metal layer 76a in a good state.

  In the inspection device 11, when the contact state determination device 1 determines that the contact state between the probes PL1 and PL2 and the positive electrode terminal 74 and the metal layer 76a is good, the processing unit 6 is a part of the inspection device 11. To perform the inspection process. Prior to the execution of this inspection process, the processing unit 6 causes the current supply unit 2 to stop supplying the AC inspection current I1 to the secondary battery 70 and causes the voltage measurement unit 12 to set the battery voltage Vbat. Start measurement.

  In this inspection process, the processing unit 6 receives the second voltage data Dv indicating the voltage value of the battery voltage Vbat output from the voltage measurement unit 12 and compares it with the voltage range data Dra read from the storage unit 8. Then, the quality of the secondary battery 70 is inspected. Specifically, when the voltage value of the battery voltage Vbat indicated by the second voltage data Dv is included in the voltage range indicated by the voltage range data Dra (the voltage range serving as a pass / fail determination index), the processing unit 6 The secondary battery 70 is determined to be in a good state (for example, the insulating state of the synthetic resin layer 76b corresponding to the inner wall of the exterior member 71 is good (no damage such as pinholes occurs)). On the other hand, when the voltage value of the battery voltage Vbat is not included in the voltage range indicated by the voltage range data Dra, the processing unit 6 indicates that the secondary battery 70 is in a defective state (for example, corresponding to the inner wall of the exterior member 71). It is determined that the insulating state of the synthetic resin layer 76b is poor (damage such as pinholes occurs).

  Thereby, the inspection process is completed, and thereafter the processing unit 6 causes the output unit 7 to output the result of the inspection process by executing the output process. Therefore, the user of the inspection device 11 can grasp the quality of the secondary battery 70 based on the result of the inspection process output to the output unit 7.

  As described above, in the contact state determination device 1 and the contact state determination method, the frequency is the same as that of the AC inspection current I1 supplied to the secondary battery 70 to be measured, and the phase with respect to the AC inspection current I1. Is detected by an arbitrary angle within an angle range of more than 0 degrees and less than 90 degrees (the angle θ is an arbitrary value within an angle range of less than 0 degrees and more than −90 degrees), and a detection signal V3 is generated By detecting the detection voltage signal V2 indicating the AC voltage V1 generated between the base ends of the probes PL1 and PL2 (between the measurement terminals TP1 and TP2) when the AC inspection current I1 is supplied, by detecting the detection signal V3. A DC detection voltage V5 is generated, and based on the DC detection voltage V5 (based on an impedance value (| Z | × cos θ) calculated based on the DC detection voltage V5) or a voltage value of the DC detection voltage V5 Based on), to determine the state of contact between each electrode EL1, EL2 (positive terminal 74, the metal layer 76a in this example) of the tip and the secondary battery 70 of the probe PL1, PL2.

  Therefore, according to the contact state discriminating apparatus 1 and the contact state discriminating method, the auxiliary measurement terminal is used even when the capacitance Cc having a non-negligible magnitude is generated between the probes PL1 and PL2. Without this, it is possible to accurately determine the contact state between the tips of the probes PL1 and PL2 and the electrodes EL1 and EL2 of the secondary battery 70.

  In the contact state determination device 1 and the contact state determination method, the contact state between the tips of the probes PL1 and PL2 and the electrodes EL1 and EL2 of the secondary battery 70 is very close to the open state and the open state. The impedance is less than the value of the impedance calculated based on the DC detection voltage V5 generated by the detection by the detection unit 5 in the first contact state that is one of the states, and the contact state is a short-circuit state and a short-circuit state. Any value (or higher than the impedance value calculated based on the DC detection voltage V5 generated by the detection by the detection unit 5 in the second contact state in which the state is very close to the state (or The detection unit is below the voltage value of the DC detection voltage V5 generated by the detection by the detection unit 5 in the first contact state, and in the second contact state. Threshold to any value) above the voltage value of the DC detection voltage V5 generated by detection is predefined by.

  Therefore, according to the contact state determination device 1 and the contact state determination method, the probes PL1 and PL2 are connected to the electrodes EL1 and EL1 of the secondary battery 70 for the inspection of the secondary battery 70 and the threshold value thus defined. By comparing the impedance value (or the voltage value of the DC detection voltage V5) calculated based on the DC detection voltage V5 detected by the voltage detection unit 3 when contacting the EL2, the probes PL1, PL2 Thus, it is possible to reliably determine whether or not the contact state between each of the tips and the electrodes EL1 and EL2 of the secondary battery 70 is good.

  Further, according to the inspection device 11 for the secondary battery 70 provided with the contact state determination device 1 described above, the contact state determination device 1 causes the tips of the probes PL1 and PL2 and the electrodes EL1 and EL2 of the secondary battery 70 to be detected. Since the battery voltage Vbat of the secondary battery 70 can be measured by the voltage measurement unit 12 in a state where the contact state between and the battery is reliably in a good state, the voltage measurement unit 12 can accurately measure the battery voltage Vbat, The quality of the secondary battery 70 can be accurately inspected based on the accurate battery voltage Vbat.

  In the above example, the processing unit 6 adopts a configuration that functions as part of the contact state determination device 1 and also functions as part of the inspection device 11. It is also possible to adopt a configuration in which a processing unit that functions as a unit and a processing unit that functions as a part of the inspection apparatus 11 are separately provided.

  Further, in the above example, a configuration in which the pair of the positive electrode terminal 74 and the metal layer 76a of the secondary battery 70 is used as each of the electrodes EL1 and EL2 of the secondary battery 70, but the negative electrode terminal 75 and the metal layer are used. The present invention can also be applied to a configuration using the set 76a and a configuration using the set of the positive electrode terminal 74 and the negative electrode terminal 75.

1 Contact state discrimination device
2 Current supply units 2a and 2b A pair of current output terminals
3 Voltage detector 3a, 3b A pair of voltage input terminals
4 Detection signal generator
5 detector
6 Processing Unit 11 Inspection Device 70 Secondary Battery EL1, EL2 Pair of Electrodes I1 AC Inspection Current PL1, PL2 Pair of Probes V1 AC Voltage V2 Detection Voltage Signal V3 Detection Signal V5 DC Detection Voltage
θ angle

Claims (7)

A contact state discriminating apparatus for discriminating a contact state between a pair of probes brought into contact with a pair of electrodes to be measured.
A pair of current output terminals connected to the pair of probes, respectively, and a current supply unit for supplying an AC inspection current to the object to be measured through the pair of probes;
A voltage detection unit for detecting an alternating voltage generated between the pair of probes when the pair of voltage input terminals are connected to the pair of probes, respectively, in the supply state of the alternating current inspection current; and
A detection signal generation unit that generates a detection signal that has the same frequency as the AC inspection current and has a phase delayed from the AC inspection current by an arbitrary angle within an angle range of more than 0 degrees and less than 90 degrees;
A detection unit that generates a DC detection voltage by detecting the detection voltage signal with the detection signal;
A contact state determination apparatus comprising: a processing unit that executes a contact determination process for determining the contact state based on the DC detection voltage.   In the contact determination process, the processing unit includes the alternating current inspection current and the direct current detection voltage when the contact state is in a first contact state in which the contact state is very close to the open state or the open state. When the second contact state is lower than the impedance value calculated in advance based on the pair of probes and the contact state is one of a short-circuit state and a state very close to the short-circuit state. A threshold value preliminarily defined as a value exceeding an impedance value between the pair of probes calculated in advance based on an AC inspection current and the DC detection voltage, and the pair of probes are brought into contact with the pair of electrodes. And comparing the impedance value between the pair of probes calculated based on the AC inspection current and the DC detection voltage when The contact state determination device according to claim 1, wherein the contact state is good when an impedance value is less than or equal to the threshold value, and the contact state is bad when the impedance value exceeds the threshold value. .   In the contact determination process, the processing unit is configured to detect the DC detection generated by the detection unit when the contact state is a first contact state in which the contact state is one of an open state and a state very close to the open state. The voltage of the DC detection voltage generated by the detection unit when the second contact state is lower than the voltage value of the voltage and the contact state is one of a short circuit state and a state very close to the short circuit state. A voltage value of the DC detection voltage is compared with a threshold value preliminarily defined to a value exceeding the value and the DC detection voltage generated when the pair of probes are in contact with the pair of electrodes. The contact state is determined to be good when the value is equal to or less than the threshold value, and the contact state is determined to be defective when the voltage value of the DC detection voltage exceeds the threshold value. Placing a contact state detecting apparatus.   The contact state determination device according to claim 1, the pair of probes, a pair of measurement terminals to which the pair of probes are respectively connected, and a pair of voltage measurement terminals for the pair of measurement An inspection apparatus for a secondary battery, comprising: a voltage measuring unit that is connected to each terminal and measures a DC voltage generated between the pair of electrodes of the secondary battery as the measurement target. A contact state determination method for determining a contact state between a pair of probes to be brought into contact with a pair of electrodes to be measured.
A current supply step in which a pair of current output terminals are connected to the pair of probes, respectively, and an AC inspection current is supplied to the measurement object via the pair of probes;
A voltage detection step in which a pair of voltage input terminals are connected to the pair of probes, respectively, and an alternating voltage generated between the pair of probes in the supply state of the alternating current inspection current is detected as a detection voltage signal;
A detection signal generation step of generating a detection signal having the same frequency as the AC inspection current and a phase delayed from the AC inspection current by an arbitrary angle within an angle range of more than 0 degrees and less than 90 degrees;
A detection step of generating a DC detection voltage by detecting the detection voltage signal with the detection signal;
A contact state determination method for executing a contact determination step of determining the contact state based on the DC detection voltage.   In the contact determination step, the contact state is calculated in advance based on the alternating current inspection current and the direct current detection voltage in the first contact state in which the contact state is one of an open state and a state extremely close to the open state. The alternating current inspection current when the second contact state is lower than the impedance value between the pair of probes and the contact state is one of a short circuit state and a state very close to the short circuit state, and A threshold value preliminarily defined to a value exceeding the impedance value between the pair of probes calculated in advance based on a DC detection voltage, and the pair of probes when the pair of electrodes are in contact with the pair of electrodes Comparing the impedance value between the pair of probes calculated based on the AC inspection current and the DC detection voltage, the impedance The contact state when the value is below the threshold value is good, the contact state determination method according to claim 5, wherein to determine that the contact state is not normal when the value of the impedance is above the threshold.   In the contact determination step, the contact state is lower than a voltage value of the DC detection voltage generated by the detection when the contact state is a first contact state that is one of an open state and a state very close to the open state. In addition, the contact state is preliminarily specified to a value that exceeds the voltage value of the DC detection voltage generated by the detection when the contact state is the second contact state that is one of the short-circuit state and the state extremely close to the short-circuit state. And comparing the DC detection voltage generated when the pair of probes are in contact with the pair of electrodes, the voltage value of the DC detection voltage is less than the threshold 6. The contact state according to claim 5, wherein the contact state is sometimes good, and the contact state is determined to be defective when the voltage value of the DC detection voltage exceeds the threshold value. Another way.

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