Impurity detection assistance device and impurity detection assistance method

Abstract

The impurity detection auxiliary device (100) includes: a pipe (102) through which a liquid to be inspected flows; a first electrode and a second electrode which are arranged in the pipe (102) and are configured to be able to apply an alternating voltage to or superimpose an alternating current on the liquid to be inspected in a space extending between a first position and a second position that are offset from each other in the extension direction of the pipe (102); a power supply portion (106) which applies an alternating voltage between the electrodes or superimposes an alternating current; a measurement portion (108) which measures a current generated between the electrodes due to the application of the alternating voltage or measures a voltage generated between the electrodes due to the superposition of the alternating current; and a calculation portion (110) which calculates a resistance of the liquid to be inspected using the measurement result of the measurement portion (108), the resistance of the liquid to be inspected being a criterion for determining whether or not the liquid to be inspected contains an electrically conductive impurity.

Description

Technical Field

[0001] This disclosure relates to an auxiliary device and method for impurity detection. Background Technology

[0002] When manufacturing solid-liquid mixtures with electronic conductivity, conductive particles such as metal particles can sometimes be introduced as impurities. When such solid-liquid mixtures containing conductive impurities are used in electronic devices, there is a risk of malfunction due to these impurities. Examples of such electronic devices include energy storage devices such as lithium-ion batteries, lithium-ion rechargeable batteries, alkaline dry batteries, double-layer capacitors, and electrochemical capacitors. Furthermore, electrode slurries used in these energy storage devices can be examples of solid-liquid mixtures. If conductive impurities are introduced into the electrode slurry, these impurities may cause short circuits between the positive and negative electrodes. To address this, for example, Patent Document 1 discloses a method for detecting metallic foreign objects contained in an aqueous slurry containing electrode active material and a particulate binder using magnetic detection.

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: International Publication No. 2014 / 142045 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] Existing methods for detecting conductive impurities using magnetism cannot detect conductive impurities composed of non-magnetic materials. Therefore, the detection rate of conductive impurities is insufficient in existing methods.

[0008] This disclosure is made in view of the following circumstances, and its purpose is to provide a technique for improving the detection rate of conductive impurities in the tested liquid.

[0009] [Technical solutions used to address technical problems]

[0010] One aspect of this disclosure is an auxiliary device for impurity detection. The device includes: a piping supplying a test liquid; a first electrode and a second electrode disposed within the piping and configured to apply an alternating voltage to the test liquid within a space extending between a first position and a second position on the piping, or to superimpose an alternating current onto it, the second position being offset from the first position in the direction of pipe extension; a power supply unit applying an alternating voltage or superimposing an alternating current between the first and second electrodes; a measuring unit measuring the current generated between the first and second electrodes due to the application of the alternating voltage, or measuring the voltage generated between the first and second electrodes due to the superposition of the alternating current; and a calculation unit calculating the resistance of the test liquid using the measurement results from the measuring unit, the resistance of which is an indicator for determining whether the test liquid contains conductive impurities.

[0011] Another aspect of this disclosure is an auxiliary method for impurity detection. The method includes: directing the test liquid to a piping system; applying an alternating voltage or superimposed alternating current to the test liquid within a space extending between a first position on the piping system and a second position offset from the first position in the direction of the piping's extension; measuring the current generated by the applied alternating voltage or the voltage generated by the superimposed alternating current; and calculating the resistance of the test liquid using the measurement results. The resistance of the test liquid is used as an indicator to determine whether the test liquid contains conductive impurities.

[0012] Any combination of the above-mentioned constituent elements, as well as the result of converting the expression of this disclosure between methods, apparatus, systems, etc., are also valid as solutions of this disclosure.

[0013] Invention Effects

[0014] According to this disclosure, the detection rate of conductive impurities in the tested liquid can be improved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a coating apparatus equipped with the impurity detection auxiliary device of Embodiment 1.

[0016] Figure 2 (A) Figure 2 (C) is a schematic diagram of the electrode section.

[0017] Figure 3 This is a flowchart illustrating an example of the impurity detection auxiliary method of Implementation Method 1.

[0018] Figure 4 (A) Figure 4 (C) is a schematic diagram of the electrode section of the impurity detection auxiliary device of Embodiment 2. Detailed Implementation

[0019] Hereinafter, the present disclosure will be described with reference to the accompanying drawings and based on preferred embodiments. These embodiments are not intended to limit the present disclosure, but are merely illustrative; not all features and combinations thereof described in the embodiments are substantive content of the present disclosure. Identical or equivalent constituent elements, components, and processes shown in the various drawings are labeled with the same reference numerals, and repeated descriptions are appropriately omitted. Furthermore, the scales or shapes of the parts shown in the figures are provided for ease of explanation and are not to be interpreted limitingly unless specifically mentioned. In addition, the use of terms such as "first," "second," etc., in this specification or claims does not indicate any order or importance unless specifically mentioned, but is only used to distinguish one component from others. Furthermore, in the various drawings, parts of components that are not important for describing the embodiments are omitted from the illustration.

[0020] (Implementation Method 1)

[0021] Figure 1 This is a schematic diagram of a coating apparatus 1 equipped with the impurity detection auxiliary device 100 of Embodiment 1. Figure 1 In this text, a portion of the constituent elements of each device is depicted as a functional block. These functional blocks, as hardware components, are implemented by elements or circuits, such as a computer's CPU or memory; as software components, they are implemented through computer programs, etc. Those skilled in the art will understand that these functional blocks can be implemented in various forms through a combination of hardware and software.

[0022] The coating apparatus 1 includes a coating die head 2, a valve 4, a tank 6, a pump 8, a delivery pipe 10, a return pipe 12, and a die head supply pipe 14.

[0023] The coating die 2 is an apparatus for applying coating material 18 to the substrate 16. As an example, the coating apparatus 1 of this embodiment is used to manufacture electrode plates for secondary batteries. Electrode plates for secondary batteries are sheet-like electrode raw materials obtained by coating an electrode slurry onto a current collector and drying it. Therefore, in this embodiment, the substrate 16 is the current collector of the secondary battery, and the coating material 18 is the electrode slurry for the secondary battery. The current collector is, for example, a metal foil. The electrode slurry is an electronically conductive solid-liquid mixture containing at least one of a solvent, an electrode active material, and a conductive additive. In the case of a typical lithium-ion secondary battery, the positive electrode plate is manufactured by coating an electrode slurry onto an aluminum foil, the electrode slurry containing a positive electrode active material such as lithium cobalt oxide or lithium iron phosphate. Additionally, the positive electrode slurry may also contain conductive additives such as graphite. In addition, the negative electrode plate is made by coating an electrode paste onto a copper foil, the electrode paste containing negative electrode active materials (or conductive additives) such as graphite.

[0024] The coating die 2 is configured such that the nozzle 22 is opposite to the circumferential surface of the support roller 20 at a predetermined interval. By rotating the support roller 20, the body to be coated 16 is continuously conveyed to the position opposite the nozzle 22 on the support roller 20.

[0025] A valve 4 is connected to the coating die 2 via a die supply pipe 14. The valve 4 can switch between supplying and not supplying paint 18 to the coating die 2. The coating apparatus 1 can spray paint 18 from the coating die 2 onto the workpiece 16 while the paint 18 is being supplied to the coating die 2. A tank 6 is connected to the valve 4 via a delivery pipe 10 and a return pipe 12.

[0026] Tank 6 stores paint 18. A pump 8 is installed in the delivery piping 10, and the paint 18 is delivered from tank 6 to valve 4 by the pump 8. Valve 4 supplies the paint 18 from tank 6 to coating die 2 via die supply piping 14. Alternatively, valve 4 returns the paint 18 from tank 6 to tank 6 via return piping 12.

[0027] Since valve 4 supplies paint 18 to coating die 2, paint 18 can be sprayed from coating die 2, thereby forming a coated portion 18a of paint 18 on the coated body 16. Furthermore, since valve 4 returns paint 18 to tank 6, the coating of paint 18 from coating die 2 can be stopped, thereby forming an uncoated portion 16a of paint 18 on the coated body 16. That is, paint 18 can be intermittently applied to the coated body 16 by means of valve 4. The uncoated portion 16a is used for bonding center leads of electrodes, etc. However, the configuration of each part of the coating apparatus 1 is not limited to the above configuration.

[0028] The coating apparatus 1 is provided with an impurity detection auxiliary device 100 according to this embodiment. The impurity detection auxiliary device 100 includes a piping 102, an electrode section 104, a power supply section 106, a measuring section 108, a calculation section 110, and a determination section 112.

[0029] Piping 102 is a flow path for the fluid to be tested, which is the fluid used to check for conductive impurities. Conductive impurities may be, for example, metals. In this embodiment, the area between tank 6 and pump 8 in the delivery piping 10 constitutes piping 102. That is, an impurity detection auxiliary device 100 is provided in the delivery piping 10. Furthermore, the coating 18, in other words, the electrode slurry, corresponds to the fluid to be tested.

[0030] Alternatively, the impurity detection auxiliary device 100 may be installed in the area between the pump 8 and the valve 4 in the delivery piping 10. Furthermore, the impurity detection auxiliary device 100 may also be installed in the return piping 12 or the die supply piping 14, etc. Additionally, the coating apparatus 1 can be interpreted as a circulation or delivery device containing the coating material 18, which is composed of the tank 6, the pump 8, the delivery piping 10, and the return piping 12. In this case, the impurity detection auxiliary device 100 installed in the delivery piping 10 or the return piping 12 can also be interpreted as being installed in the circulation or delivery device. Furthermore, the coating apparatus 1 is not limited to manufacturing electrode plates for secondary batteries, and the coated body 16 and the coating material 18 may not be electrode plates or electrode slurries. Furthermore, the impurity detection auxiliary device 100 may also be installed in a device other than the coating apparatus 1, such as a test liquid manufacturing apparatus.

[0031] The electrode section 104 includes a first electrode 114 and a second electrode 116. Hereinafter, the first electrode 114 and the second electrode 116 will sometimes be referred to as a pair of electrodes. Figure 2 (A) Figure 2 (C) is a schematic diagram of the electrode section 104. Figure 2 (A) is the first example of electrode section 104. Figure 2 (B) is the second example of electrode section 104. Figure 2 (C) is the third example of electrode section 104. Additionally, in Figure 2 (B) and Figure 2 In (C), the illustration of the power supply unit 106 is omitted.

[0032] A pair of electrodes are disposed within the piping 102. Furthermore, the electrode section 104 of this embodiment has a rod-shaped body 118, which is inserted into the piping 102 and disposed at a distance from the piping 102. A first electrode 114 is disposed within the piping 102, and a second electrode 116 is disposed within the rod-shaped body 118. The first electrode 114 and the second electrode 116 are insulated from each other. The first electrode 114 and the second electrode 116 are made of a conductive material. For example, the volume resistivity is 0.1 Ω·cm or less. Specific examples of materials constituting the first electrode 114 and the second electrode 116 include insoluble metals such as stainless steel, titanium, platinum, gold, niobium, and ruthenium, or carbon. These materials can also be appropriately combined.

[0033] The first electrode 114 is disposed at least on the inner wall (inner circumferential surface) of the piping 102. The first electrode 114 may be disposed on the entire inner wall of the piping 102 or on a portion thereof. When the first electrode 114 is disposed on a portion of the inner wall, it may be a region in the direction of flow of the test fluid or a region in the circumferential direction of the piping 102. Alternatively, the entire piping 102 may be constructed of an insoluble metal or the like, and the entire piping 102 may constitute the first electrode 114. That is, the first electrode 114 may be disposed only on the surface of the inner wall of the piping 102 or may be disposed inside the inner wall.

[0034] The second electrode 116 is disposed at least on the outer wall (outer peripheral surface) of the rod-shaped body 118. The second electrode 116 may be disposed on the entire outer wall of the rod-shaped body 118 or on a portion thereof. When the second electrode 116 is disposed on a portion of the outer wall, it may be a region in the direction of flow of the test liquid or a region in the circumferential direction of the rod-shaped body 118. Alternatively, the entire rod-shaped body 118 may be constructed of an insoluble metal or the like, and the entire rod-shaped body 118 may constitute the second electrode 116. That is, the second electrode 116 may be disposed only on the surface of the outer wall of the rod-shaped body 118 or disposed inside the outer wall.

[0035] The first electrode 114 and the second electrode 116 are configured to apply an alternating voltage or superimpose an alternating current onto the fluid under test within a space extending between any first position 102a of the piping 102 and a second position 102b offset from the first position 102a in the extending direction of the piping 102. In this embodiment, the first electrode 114 and the second electrode 116 are elongated strips extending in the extending direction of the piping 102. Therefore, the pair of electrodes extend radially spaced apart from each other and parallel to the axis of the piping 102. Preferably, the pair of electrodes are configured such that the distance between them is equal at any position in the extending direction of the piping 102.

[0036] Therefore, an alternating voltage or an superimposed alternating current can be applied to the entire liquid being tested, which extends between the first position 102a and the second position 102b along the extension direction of the piping 102, in other words, the flow direction of the liquid being tested. The distance between the first position 102a and the second position 102b, in other words, the length of the first electrode 114 and the second electrode 116 in the extension direction of the piping 102, is, for example, greater than or equal to the distance between a pair of electrodes, and also, for example, greater than or equal to the diameter of the piping 102.

[0037] Furthermore, the rod-shaped body 118 is configured such that the distance to the inner wall of the pipe 102 is substantially equal at each position in the extending direction of the pipe 102. That is, the rod-shaped body 118 extends parallel to the axis of the pipe 102. This ensures that the distance between a pair of electrodes (the radial distance of the pipe 102) is substantially equal in the extending direction of the pipe 102. As a result, the detection accuracy of the impurity detection auxiliary device 100 for conductive impurities can be improved. Furthermore, the rod-shaped body 118 is configured such that the distance to the inner wall of the pipe 102 is substantially equal at each position in the circumferential direction of the rod-shaped body 118. That is, the pipe 102 and the rod-shaped body 118 are arranged coaxially. This ensures that the distance between a pair of electrodes is substantially equal in the circumferential direction of the rod-shaped body 118. As a result, the detection accuracy of the impurity detection auxiliary device 100 for conductive impurities can be improved. In other words, the rod-shaped body 118 constituting the second electrode 116 is inserted through the center of the pipe 102, and therefore does not deviate radially from the pipe 102, but extends parallel to and without tilting relative to the extension direction of the pipe 102.

[0038] exist Figure 2 In the first example shown in (A), the rod 118 is hollow. The interior of the rod 118 is sealed, and the fluid being tested does not flow. Figure 2 In the second example shown in (B), the rod 118 is solid. By using a hollow or solid rod 118, the increased pressure loss of the fluid being tested as it passes through pipe 102 due to the rod 118 can be suppressed. On the other hand, in Figure 2 In the third example shown in (C), the rod-shaped body 118 is a cylindrical mesh. The liquid to be tested can flow within the piping 102 while passing through the opening of the mesh inside and outside the rod-shaped body 118. By using the cylindrical mesh rod-shaped body 118, the contact area between the second electrode 116 and the liquid to be tested can be increased, thereby improving the detection accuracy of the impurity detection auxiliary device 100 for conductive impurities.

[0039] The power supply unit 106 applies an alternating voltage or superimposed alternating current between the first electrode 114 and the second electrode 116. The power supply unit 106 can be configured using a known AC / DC converter, inverter, control circuit, etc. For example, the first electrode 114 is connected to the negative output terminal of the power supply unit 106, and the second electrode 116 is connected to the positive output terminal of the power supply unit 106. Therefore, the first electrode 114 is the negative electrode, and the second electrode 116 is the positive electrode. Alternatively, the first electrode 114 can be the positive electrode, and the second electrode 116 can be the negative electrode. The control circuit, for example, is configured using a microcomputer, and can control each switching element of the power supply unit 106 so that the current or voltage is maintained at a target value based on the measurement results of the measuring unit 108.

[0040] The measuring unit 108 measures a current generated between the first electrode 114 and the second electrode 116 due to the application of an alternating voltage. Alternatively, the measuring unit 108 measures a voltage generated between the first electrode 114 and the second electrode 116 due to the superposition of alternating currents. When measuring the current generated between a pair of electrodes, the measuring unit 108 can be configured with a known ammeter or FRA (Frequency Response Analyzer) electrically connected to the pair of electrodes. When measuring the voltage generated between a pair of electrodes, the measuring unit 108 can be configured with a known voltmeter or FRA electrically connected to the pair of electrodes.

[0041] The calculation unit 110 calculates the resistance of the tested liquid using the measurement results from the measurement unit 108. As an example, the calculation unit 110 calculates the resistance of the tested liquid using the AC impedance method.

[0042] When an alternating current voltage is applied between a pair of electrodes by the power supply unit 106, the current generated between the electrodes is measured by the measuring unit 108 through the test liquid. In this case, the calculation unit 110 can calculate the resistivity of the test liquid based on the value of the current and the value of the alternating current voltage applied between the electrodes. The magnitude of the applied alternating current voltage can be appropriately selected based on the electrode area, the distance between the electrodes, the type of test liquid, etc., but is preferably 1 to 100 mV, and more preferably 5 to 50 mV. The application time of the alternating current voltage is not particularly limited. Alternatively, a bias voltage can be applied to the alternating current voltage.

[0043] Furthermore, when the power supply unit 106 superimposes an alternating current between a pair of electrodes, the voltage generated between the electrodes is measured by the measuring unit 108 using the test liquid. In this case, the calculation unit 110 can calculate the resistivity of the test liquid based on the value of the voltage and the value of the superimposed alternating current between the electrodes. The magnitude of the superimposed alternating current can be appropriately selected based on the electrode area, the distance between the electrodes, the type of test liquid, etc., but is preferably 5nA to 5A, and more preferably 50nA to 500mA. The superposition time of the alternating current is not particularly limited. Alternatively, a bias voltage can be applied to the alternating current.

[0044] Particularly preferred is to apply an alternating current (AC) voltage between a pair of electrodes and calculate the resistance of the tested liquid using the AC impedance method. The frequency of the AC voltage can be appropriately selected based on the electrode area, the distance between the electrodes, the type of tested liquid, etc., but is preferably 1Hz to 1,000,000Hz, and more preferably 10,000Hz to 1,000,000Hz. This shortens the time required to calculate the resistance and further improves the accuracy of the resistance calculation.

[0045] When conductive impurities such as metals are mixed into the solid-liquid mixture used as the test liquid, the resistance of the test liquid will decrease regardless of whether the impurity is magnetic or non-magnetic. In other words, the resistance of the test liquid becomes an indicator of whether it contains conductive impurities. Therefore, the change in resistance of the test liquid flowing within piping 102 can be detected by measuring resistance based on AC impedance method, thereby identifying the presence of conductive impurities.

[0046] The determination unit 112 determines whether the tested liquid contains conductive impurities based on the resistance calculated by the calculation unit 110. For example, the determination unit 112 may pre-store the resistance value of the tested liquid that does not contain conductive impurities as a reference value. The determination unit 112 compares the resistance calculated by the calculation unit 110 with the reference value. Then, if the difference between the calculated resistance and the reference value exceeds a predetermined threshold, the determination unit 112 determines that the tested liquid contains conductive impurities. This threshold can be appropriately set based on the designer's experiments or simulations. For example, the threshold may also be zero.

[0047] Furthermore, the determination unit 112 can also determine whether the tested liquid contains conductive impurities in the following manner: That is, the electrode unit 104 of this embodiment generates an electric field in the tested liquid within a space that extends between the first position 102a and the second position 102b. Therefore, an alternating current voltage can be continuously applied to the tested liquid, or an alternating current can be continuously superimposed for a predetermined continuous time rather than instantaneously. Therefore, the power supply unit 106 continuously or periodically changes the frequency of the alternating current voltage or alternating current applied to the tested liquid. Then, the measurement unit 108 measures the current or voltage generated between a pair of electrodes at multiple different frequencies. Therefore, the calculation unit 110 can calculate the resistance of the tested liquid at each frequency. The determination unit 112 determines whether conductive impurities are present based on the multiple resistances calculated by the calculation unit 110. For example, the determination unit 112 determines whether the difference between the resistance value at each frequency and the corresponding reference value exceeds a threshold. Then, by combining their determination results, for example, based on the number of times the threshold is exceeded, the presence or absence of conductive impurities is determined. This improves the detection accuracy of conductive impurities.

[0048] Furthermore, the determination unit 112 can also determine the presence or absence of conductive impurities based on the size of the arc in the equivalent circuit model obtained by the AC impedance method. Alternatively, in addition to the resistance of the tested liquid, the determination unit 112 can also determine the presence or absence of conductive impurities based on the capacitance (electrostatic capacitance) of the tested liquid.

[0049] As an example, the determination result of the determination unit 112 is sent to the control device 24. The control device 24 may also display the determination result of the determination unit 112 on a monitor (not shown). Alternatively, if the determination unit 112 determines that the tested liquid contains conductive impurities, the control device 24 may notify the user of the impurity detection aid 100 of the determination result using a known notification method. The notification method is not particularly limited, and known methods such as generating an alarm sound or illuminating an alarm light can be used. Thus, the user can monitor the presence or absence of conductive impurities in a practical manner. Furthermore, the user can more quickly ascertain the presence of conductive impurities.

[0050] Alternatively, the voltage or current value measured by the measuring unit 108 may be sent to the control device 24. The control device 24 may also display the waveform of the voltage or current value on an oscilloscope (not shown). Alternatively, the resistance value calculated by the calculation unit 110 may be sent to the control device 24. The control device 24 may also display the resistance value on a monitor. Alternatively, the resistance value displayed on the monitor may be multiple resistance values ​​obtained by varying the frequency of the AC voltage or AC current. In this case, the user can determine the presence or absence of conductive impurities based on the resistance value displayed on the monitor. If the resistance value itself is used by the user, the determination unit 112 may also be omitted.

[0051] As an example, the user can give instructions regarding the execution of impurity detection processing via control device 24 or through the operating program within control device 24. The same applies to changes to the settings for impurity detection processing. Furthermore, control device 24 can also control valve 4 or pump 8.

[0052] Figure 3 This is a flowchart illustrating an example of the impurity detection auxiliary method of Embodiment 1. The process is, for example, repeatedly executed at predetermined time intervals.

[0053] First, an alternating voltage or an superimposed alternating current is applied between the first electrode 114 and the second electrode 116 (S101). Next, the current generated between the first electrode 114 and the second electrode 116 due to the applied alternating voltage is measured, or the voltage generated between the first electrode 114 and the second electrode 116 due to the superimposed alternating current is measured (S102). Next, the resistance of the tested liquid is calculated based on the measured current or voltage (S103). Then, it is determined whether the difference between the calculated resistance value and the reference value exceeds a threshold value (S104).

[0054] If the difference between the resistance value and the reference value exceeds a threshold ("Yes" in S104), the presence of impurities in the tested liquid is reported to the user (S105), and the procedure ends. If the difference between the resistance value and the reference value is below the threshold ("No" in S104), no notification is made to the user, and the procedure ends. Furthermore, in step S104, the determination of whether the difference between a single resistance value and the reference value exceeds a threshold is used as the determination of whether conductive impurities are present in the tested liquid. However, this is not limited to this; it is also possible to determine whether the difference between multiple resistance values ​​obtained by varying the frequency of AC voltage or AC current exceeds a threshold, and to combine multiple determination results to determine whether conductive impurities are present.

[0055] As described above, the impurity detection auxiliary device 100 of this embodiment includes: a piping 102 for supplying the test liquid; a first electrode 114 and a second electrode 116 disposed within the piping 102 and configured to apply an alternating voltage or superimposed an alternating current to the test liquid extending in the space between a first position 102a and a second position 102b of the piping 102, i.e., to the entire test liquid extending in the space, wherein the second position 102b is offset from the first position 102a in the extending direction of the piping 102; a power supply unit 106 for applying an alternating voltage or superimposed an alternating current between the two electrodes; a measuring unit 108 for measuring the current generated between the two electrodes due to the application of the alternating voltage or for measuring the voltage generated between the two electrodes due to the superposition of the alternating current; and a calculation unit 110 for calculating the resistance of the test liquid using the measurement result of the measuring unit 108, wherein the resistance of the test liquid is a determination index for whether the test liquid contains conductive impurities.

[0056] The impurity detection auxiliary device 100 of this embodiment measures the resistance, which is a criterion for determining the presence or absence of conductive impurities, by applying an alternating voltage or superimposing an alternating current to the liquid being tested. Therefore, even if the impurity is a non-magnetic substance, a highly reliable criterion can be obtained. Thus, the detection rate of conductive impurities in the liquid being tested can be improved. Furthermore, in order to generate an electric field in the liquid being tested flowing within the piping 102, conductive impurity detection can be performed while the liquid being tested is being transported. That is, linear impurity detection processing can be achieved. Moreover, since sample collection and other operations are not required, the total volume of the liquid being tested can be easily checked. Therefore, the introduction of foreign matter into the next process can be suppressed.

[0057] Furthermore, an alternating voltage or an alternating current is applied to the liquid being inspected within the space extended between the first position 102a and the second position 102b of the piping 102, wherein the second position 102b is offset from the first position 102a in the direction of pipe extension. Thus, because the area where conductive impurities are energized can be expanded to the flow direction of the liquid being inspected, the detection efficiency of conductive impurities can be improved.

[0058] As an example, the tested liquid is an electrode slurry containing at least one of a solvent, an electrode active material, and a conductive additive. In this case, since conductive impurities can be detected with high precision, short circuits between the positive and negative electrodes caused by the conductive impurities themselves can be suppressed. Furthermore, in an energy storage device where the electrolyte is located between the positive and negative electrodes, when the positive electrode slurry contains conductive impurities (especially metallic impurities), these impurities may dissolve into the electrolyte during charging, be reduced, and precipitate on the surface of the negative electrode. When this precipitation is repeated, the conductive impurities can grow dendritively, penetrate the spacer, and reach the positive electrode, causing a short circuit. Therefore, by increasing the detection rate of conductive impurities, short circuits caused by dendrite formation can also be suppressed.

[0059] Furthermore, as an example, piping 102 is provided in the coating apparatus 1, which includes a tank 6 storing a coating die 2 for applying the test liquid to the coated body 16 and the test liquid. Alternatively, piping 102 is provided in a circulation device or a delivery device for the test liquid. This allows for impurity detection during the process of delivering the test liquid from the tank 6 to the coating die 2. Furthermore, by configuring an impurity detection auxiliary device 100 in the delivery piping 10 or the die supply piping 14 of the coating apparatus 1, impurity detection can be performed on the test liquid up to the point just before it is applied to the coated body 16. This further reduces the risk of foreign matter contamination into the electronic device and further improves the performance of the electronic device.

[0060] Furthermore, the impurity detection auxiliary device 100 can be installed in an existing device by utilizing a portion of the existing piping as piping 102, or by replacing a portion of the existing piping with piping 102 for the impurity detection auxiliary device 100. Therefore, the installation, replacement, and maintenance of the impurity detection auxiliary device 100 are relatively easy.

[0061] Furthermore, the impurity detection aid device 100 of this embodiment includes a determination unit 112, which determines whether the liquid being tested contains conductive impurities based on the resistance calculated by the calculation unit 110. This allows the user to more quickly ascertain the presence of conductive impurities.

[0062] Furthermore, as an example of determining whether conductive impurities are present, the power supply unit 106 continuously or periodically changes the frequency of the applied AC voltage or superimposed AC current, the measurement unit 108 measures the current or voltage at different frequencies, the calculation unit 110 calculates multiple resistances based on the current or voltage at each frequency, and the determination unit 112 determines whether conductive impurities are present based on the multiple resistances. This further improves the detection accuracy of conductive impurities.

[0063] Furthermore, in this embodiment, the first electrode 114 and the second electrode 116 are elongated strips extending along the extension direction of the piping 102. This allows for a simpler expansion of the area generating the electric field along the extension direction of the piping 102. Furthermore, the first electrode 114 is disposed on the piping 102, and the second electrode 116 is disposed on a rod-shaped body 118 inserted into the piping 102. The rod-shaped body 118 is arranged at a distance from the piping 102. Moreover, it extends parallel to the axis of the piping 102. Therefore, even when the area generating the electric field expands along the extension direction of the piping 102, it is easy to ensure a uniform distance between the two electrodes throughout the entire area, and the electric field can be generated more uniformly throughout the entire area. Furthermore, the rod-shaped body 118 can be hollow, solid, or a cylindrical mesh. When the rod-shaped body 118 is hollow or solid, it is possible to suppress the increase in pressure loss when the tested fluid passes through the piping 102. When the rod-shaped body 118 is a cylindrical mesh, the contact area between the second electrode 116 and the liquid being tested can be increased, thereby improving the detection rate of impurities.

[0064] (Implementation Method 2)

[0065] Except for the shape and arrangement of the first electrode 114 and the second electrode 116, Embodiment 2 has a configuration common to Embodiment 1. Hereinafter, this embodiment will be described with a focus on the configuration that differs from Embodiment 1, while the common configuration will be described simply or omitted.

[0066] Figure 4 (A) Figure 4 (C) is a schematic diagram of the electrode section 104 provided in the impurity detection auxiliary device 100 of Embodiment 2. Figure 4 (A) is the fourth example of electrode section 104. Figure 4 (B) is the fifth example of electrode section 104. Figure 4 (C) is the sixth example of electrode section 104. Additionally, in Figure 4 (B) and Figure 4 In (C), the illustration of the power supply unit 106 is omitted.

[0067] In this embodiment, the first electrode 114 extends at a first position 102a in a direction intersecting the extending direction of the piping 102. Furthermore, the second electrode 116 extends at a second position 102b in a direction intersecting the extending direction of the piping 102. That is, the pair of electrodes are each filter-shaped and extend radially along the piping 102. Therefore, since the area where conductive impurities are energized can be expanded in a direction intersecting the flow direction of the tested liquid, the detection efficiency of conductive impurities can be improved.

[0068] The first electrode 114 and the second electrode 116 are, for example, fixed to the conduit 102. When the conduit 102 is metallic, insulation is applied between each electrode and the conduit 102. When the conduit 102 is non-metallic, the insulation between each electrode and the conduit 102 can be omitted, and they can be in direct contact with each other.

[0069] exist Figure 4 In example 4 shown in (A), the first electrode 114 and the second electrode 116 are mesh sheets. Figure 4 In example 5 shown in (B), the first electrode 114 and the second electrode 116 are slit plates. Figure 4 In the sixth example shown in (C), the first electrode 114 and the second electrode 116 are porous sheets. The test liquid flowing in the piping 102 can pass through the mesh of each electrode to a downstream side. By making each electrode into a filter shape, the contact area between each electrode and the test liquid can be increased, thereby improving the detection accuracy of the impurity detection auxiliary device 100 for conductive impurities.

[0070] The embodiments of this disclosure have been described in detail above. The foregoing embodiments are not merely specific examples of implementing this disclosure. The content of the embodiments does not limit the technical scope of this disclosure, and various design changes, such as alterations, additions, and deletions of constituent elements, can be made without departing from the spirit of this disclosure as defined in the claims. New embodiments with design changes combine the effects of both the combined embodiments and the variations. In the foregoing embodiments, the phrases "in this embodiment" and "in this embodiment" are added to emphasize the possibility of such design changes, but design changes are permissible even in the absence of such descriptions. Any combination of the above constituent elements is also valid as a solution of this disclosure. The shadows attached to the cross-sections of the drawings do not limit the material of the object to which the shadows are attached.

[0071] The invention described above can also be identified by the items listed below.

[0072] [Project 1]

[0073] An impurity detection auxiliary device (100) includes:

[0074] Piping (102) supplies the fluid to be inspected.

[0075] The first electrode (114) and the second electrode (116) are disposed within the piping (102) and configured to apply an alternating voltage or superimpose an alternating current onto the test fluid within a space extending between a first position (102a) and a second position (102b) of the piping (102), the second position (102b) being offset from the first position (102a) in the extension direction of the piping (102).

[0076] The power supply unit (106) applies an alternating voltage or superimposed alternating current between the first electrode (114) and the second electrode (116).

[0077] The measuring unit (108) measures the current generated between the first electrode (114) and the second electrode (116) due to the application of an alternating voltage, or measures the voltage generated between the first electrode (114) and the second electrode (116) due to the superposition of alternating currents, and

[0078] The calculation unit (110) calculates the resistance of the test liquid using the measurement results of the measurement unit (108). The resistance of the test liquid is a criterion for determining whether the test liquid contains conductive impurities.

[0079] [Project 2]

[0080] The impurity detection auxiliary device (100) as described in Project 1 includes:

[0081] The determination unit (112) determines whether the liquid under test contains conductive impurities based on the resistance calculated by the calculation unit (110).

[0082] [Project 3]

[0083] As described in Project 2, the impurity detection auxiliary device, wherein...

[0084] The power supply unit (106) causes the frequency of the applied voltage or superimposed current to change continuously or in stages;

[0085] The measuring unit (108) measures the current or voltage at different frequencies;

[0086] The calculation unit (110) calculates multiple resistors based on the current or voltage at each frequency;

[0087] The determination unit (112) determines whether conductive impurities are present based on multiple resistors.

[0088] [Project 4]

[0089] The impurity detection auxiliary device (100) as described in any one of items 1 to 3, wherein,

[0090] The first electrode (114) and the second electrode (116) are elongated strips extending along the extension direction.

[0091] [Project 5]

[0092] As described in Project 4, the impurity detection auxiliary device (100) wherein,

[0093] The first electrode (114) is disposed on the piping (102);

[0094] The second electrode (116) is disposed on a rod (118) which is inserted into a pipe (102) and is spaced apart from the pipe (102).

[0095] [Project 6]

[0096] As described in Project 5, the impurity detection auxiliary device, wherein...

[0097] The rod (118) extends parallel to the axis of the pipe (102).

[0098] [Project 7]

[0099] As described in Project 5 or 6, the impurity detection auxiliary device (100) wherein,

[0100] The rod-shaped body (118) is a hollow body, a solid body, or a tubular network.

[0101] [Project 8]

[0102] The impurity detection auxiliary device (100) as described in any one of items 1 to 3, wherein,

[0103] The first electrode (114) extends at the first position (102a) in a direction intersecting the extension direction;

[0104] The second electrode (116) extends at the second position (102b) in a direction intersecting the extension direction.

[0105] [Project 9]

[0106] As described in Project 8, the impurity detection auxiliary device (100) wherein,

[0107] The first electrode (114) and the second electrode (116) are mesh sheets, slit sheets or porous sheets.

[0108] [Project 10]

[0109] The impurity detection auxiliary device (100) as described in any one of items 1 to 9, wherein,

[0110] The liquid being tested is an electrode slurry, which contains at least one of a solvent, an electrode active material, and a conductive additive.

[0111] [Project 11]

[0112] The impurity detection auxiliary device (100) as described in any one of items 1 to 10, wherein,

[0113] The piping (102) is provided in at least one of the coating device (1) for coating the body (16) with the test liquid, the circulation device for the test liquid, and the delivery device for the test liquid.

[0114] [Project 12]

[0115] An auxiliary method for impurity detection, comprising:

[0116] Direct the fluid to be tested to the piping (102);

[0117] An alternating voltage or superimposed alternating current is applied to the fluid under test in the space extended between a first position (102a) and a second position (102b) of the piping (102), the second position (102b) being offset from the first position (102a) in the direction of extension of the piping (102);

[0118] The current generated by the application of alternating voltage is measured, or the voltage generated by the superposition of alternating currents is measured.

[0119] The resistance of the tested liquid is calculated using the measurement results. The resistance of the tested liquid is used as an indicator to determine whether the tested liquid contains conductive impurities.

[0120] [Project 13]

[0121] The impurity detection auxiliary method described in Project 12 includes:

[0122] Based on the calculated resistance, it is determined whether the tested liquid contains conductive impurities.

[0123] [Project 14]

[0124] The impurity detection auxiliary method described in Project 13, wherein...

[0125] In the application of AC voltage or the superposition of AC current, the frequency of AC voltage or AC current changes continuously or in stages.

[0126] During the measurement, the current or voltage at different frequencies is measured;

[0127] In the calculation, multiple resistors are calculated based on the current or voltage at each frequency;

[0128] In the determination process, the presence of conductive impurities is assessed based on multiple resistance values.

[0129] [Industrial Availability]

[0130] This disclosure can be used in impurity detection auxiliary devices and methods.

[0131] [Explanation of reference numerals in the attached figures]

[0132] 1 Coating apparatus, 2 Coating die, 6 Can, 16 Coated body, 100 Impurity detection auxiliary device, 102 Piping, 102a First position, 102b Second position, 106 Power supply unit, 108 Measuring unit, 110 Calculation unit, 112 Judgment unit, 114 First electrode, 116 Second electrode, 118 Rod.

Claims

1. A coating apparatus for applying a test liquid to a substrate. The above-mentioned coating apparatus includes an impurity detection auxiliary device. The aforementioned impurity detection auxiliary device includes: Piping that supplies the fluid being inspected. The first and second electrodes are disposed within the aforementioned piping and configured to apply an alternating voltage or superimpose an alternating current onto the test fluid within a space extending between a first position and a second position of the aforementioned piping, wherein the second position is offset from the first position in the extension direction of the aforementioned piping. The power supply unit applies an alternating voltage or superimposed alternating current between the first electrode and the second electrode. The measuring unit measures the current generated between the first electrode and the second electrode due to the application of the aforementioned alternating voltage, or measures the voltage generated between the first electrode and the second electrode due to the superposition of the aforementioned alternating currents. The calculation unit uses the measurement results from the measurement unit to calculate the resistance of the test liquid, which is used as an indicator to determine whether the test liquid contains conductive impurities. The liquid being tested is an electrode slurry, which contains at least one of a solvent, an electrode active substance, and a conductive additive.

2. The coating apparatus as claimed in claim 1, wherein, The aforementioned impurity detection auxiliary device includes a determination unit that determines whether the liquid under test contains the aforementioned conductive impurities based on the resistance calculated by the calculation unit.

3. The coating apparatus as described in claim 2, wherein, The aforementioned power supply unit causes the frequency of the applied AC voltage or superimposed AC current to change continuously or in stages; The aforementioned measuring unit measures current or voltage at different frequencies; The calculation unit above calculates multiple resistors based on the current or voltage at each frequency; The determination unit determines whether the aforementioned conductive impurities are present based on the aforementioned plurality of resistors.

4. The coating apparatus according to any one of claims 1 to 3, wherein, The first electrode and the second electrode are elongated strips extending along the aforementioned extension direction.

5. The coating apparatus as described in claim 4, wherein, The first electrode is disposed in the aforementioned piping; The second electrode is disposed on a rod-shaped body, which is inserted through the conduit and is spaced apart from the conduit.

6. The coating apparatus as claimed in claim 5, wherein, The aforementioned rod-shaped body extends parallel to the axis of the aforementioned piping.

7. The coating apparatus as described in claim 5 or 6, wherein, The aforementioned rod-shaped bodies can be hollow, solid, or tubular meshes.

8. The coating apparatus according to any one of claims 1 to 3, wherein, The first electrode extends at the first position in a direction intersecting the extension direction. The second electrode extends at the second position in a direction intersecting the extension direction.

9. The coating apparatus as claimed in claim 8, wherein, The first electrode and the second electrode mentioned above are mesh sheets, slit sheets, or porous sheets.

10. A circulation device, which is a circulation device for the fluid being tested. The aforementioned circulation device includes an impurity detection auxiliary device. The aforementioned impurity detection auxiliary device includes: Piping that supplies the fluid being inspected. The first and second electrodes are disposed within the aforementioned piping and configured to apply an alternating voltage or superimpose an alternating current onto the test fluid within a space extending between a first position and a second position of the aforementioned piping, wherein the second position is offset from the first position in the extension direction of the aforementioned piping. The power supply unit applies an alternating voltage or superimposed alternating current between the first electrode and the second electrode. The measuring unit measures the current generated between the first electrode and the second electrode due to the application of the aforementioned alternating voltage, or measures the voltage generated between the first electrode and the second electrode due to the superposition of the aforementioned alternating currents. The calculation unit uses the measurement results from the measurement unit to calculate the resistance of the test liquid, which is used as an indicator to determine whether the test liquid contains conductive impurities. The liquid being tested is an electrode slurry, which contains at least one of a solvent, an electrode active substance, and a conductive additive.

11. The circulation device as claimed in claim 10, wherein, The aforementioned impurity detection auxiliary device includes a determination unit that determines whether the liquid under test contains the aforementioned conductive impurities based on the resistance calculated by the calculation unit.

12. The circulation device as claimed in claim 11, wherein, The aforementioned power supply unit causes the frequency of the applied AC voltage or superimposed AC current to change continuously or in stages; The aforementioned measuring unit measures current or voltage at different frequencies; The calculation unit above calculates multiple resistors based on the current or voltage at each frequency; The determination unit determines whether the aforementioned conductive impurities are present based on the aforementioned plurality of resistors.

13. The circulation device according to any one of claims 10 to 12, wherein, The first electrode and the second electrode are elongated strips extending along the aforementioned extension direction.

14. The circulation device as claimed in claim 13, wherein, The first electrode is disposed in the aforementioned piping; The second electrode is disposed on a rod-shaped body, which is inserted through the conduit and is spaced apart from the conduit.

15. The circulation device as claimed in claim 14, wherein, The aforementioned rod-shaped body extends parallel to the axis of the aforementioned piping.

16. The circulation device as claimed in claim 14 or 15, wherein, The aforementioned rod-shaped bodies can be hollow, solid, or tubular meshes.

17. The circulation device according to any one of claims 10 to 12, wherein, The first electrode extends at the first position in a direction intersecting the extension direction. The second electrode extends at the second position in a direction intersecting the extension direction.

18. The circulation device as claimed in claim 17, wherein, The first electrode and the second electrode mentioned above are mesh sheets, slit sheets, or porous sheets.

19. A delivery device for delivering a fluid to be inspected. The aforementioned conveying device includes an impurity detection auxiliary device. The aforementioned impurity detection auxiliary device includes: Piping that supplies the fluid being inspected. The first and second electrodes are disposed within the aforementioned piping and configured to apply an alternating voltage or superimpose an alternating current onto the test fluid within a space extending between a first position and a second position of the aforementioned piping, wherein the second position is offset from the first position in the extension direction of the aforementioned piping. The power supply unit applies an alternating voltage or superimposed alternating current between the first electrode and the second electrode. The measuring unit measures the current generated between the first electrode and the second electrode due to the application of the aforementioned alternating voltage, or measures the voltage generated between the first electrode and the second electrode due to the superposition of the aforementioned alternating currents. The calculation unit uses the measurement results from the measurement unit to calculate the resistance of the test liquid, which is used as an indicator to determine whether the test liquid contains conductive impurities. The liquid being tested is an electrode slurry, which contains at least one of a solvent, an electrode active substance, and a conductive additive.

20. The conveying device as claimed in claim 19, wherein, The aforementioned impurity detection auxiliary device includes a determination unit that determines whether the liquid under test contains the aforementioned conductive impurities based on the resistance calculated by the calculation unit.

21. The conveying device as claimed in claim 20, wherein, The aforementioned power supply unit causes the frequency of the applied AC voltage or superimposed AC current to change continuously or in stages; The aforementioned measuring unit measures current or voltage at different frequencies; The calculation unit above calculates multiple resistors based on the current or voltage at each frequency; The determination unit determines whether the aforementioned conductive impurities are present based on the aforementioned plurality of resistors.

22. The conveying device according to any one of claims 19 to 21, wherein, The first electrode and the second electrode are elongated strips extending along the aforementioned extension direction.

23. The conveying device as claimed in claim 22, wherein, The first electrode is disposed in the aforementioned piping; The second electrode is disposed on a rod-shaped body, which is inserted through the conduit and is spaced apart from the conduit.

24. The conveying device as claimed in claim 23, wherein, The aforementioned rod-shaped body extends parallel to the axis of the aforementioned piping.

25. The conveying device as claimed in claim 23 or 24, wherein, The aforementioned rod-shaped bodies can be hollow, solid, or tubular meshes.

26. The conveying device according to any one of claims 19 to 21, wherein, The first electrode extends at the first position in a direction intersecting the extension direction. The second electrode extends at the second position in a direction intersecting the extension direction.

27. The conveying device as claimed in claim 26, wherein, The first electrode and the second electrode mentioned above are mesh sheets, slit sheets, or porous sheets.

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