JP5189582B2 - Method and apparatus for detecting conductive particulate matter in sheet-like electrical material - Google Patents

Description

  The present invention relates to a method for detecting a conductive particle substance in a sheet-like electric material capable of accurately detecting a conductive particle substance that is present or adhered in a porous film used as a separator for a lithium ion battery, for example. And an apparatus for the same.

The sheet-like electric material is used as a member constituting an electric equipment component, and is regarded as important as a member for use as shown in Table 1, for example.

  These sheet-like electrical materials are generally used as electrical insulation and reinforcing plates, and with the current advancement of electronic technology, they are increased in density and quality, and high insulation is required.

  For this reason, in the process of manufacturing a sheet-like electrical material, for example, when particles such as metals such as gold, silver and iron, non-ferrous metals such as stainless steel, aluminum and carbon and various metal compounds are mixed, it is important in electrical insulation. This will cause problems.

  For example, in the case of a lithium ion battery accident, not only due to a cell defect, but also due to a defect in the electronic circuit in the battery pack or damage to the separator between the electrodes, the metal particles are mobilized in the electrolyte and the negative electrode side To recrystallize and short circuit.

  Also, during use or charging, metal fine particles are generated and mixed into the sheet-like electrical material due to inadequate environmental atmosphere of manufacturing equipment, sudden metal wear of dynamic equipment, excessive vibration, etc. It is said that there is abnormal heat generation and burning.

  In order to prevent such a situation from occurring, it is necessary to perform a detection operation continuously in the process of manufacturing the sheet-like electric material, and to detect and remove these conductive particle substances reliably.

The following is known as a technique for detecting a conductive particle substance intervening in a glass fiber cloth used as a base material of a printed electronic board, for example.
(1) Defect image discrimination method using a CCD camera (2) X-ray foreign substance inspection method (3) Magnetic metal detection method (4) Microwave phase or resonance method As shown.

  However, with conventional detection techniques, the time-series waveforms continuously collected by the detector include high-frequency components of microwaves, signal amplification circuits, transport vibrations of sheet-like electrical materials, and tissue structure inhomogeneities. As a result, an unnecessary noise component (noise component) is included. Therefore, when the size of the conductive particle penetration to be detected is approximately 80 μm or less, the detection signal waveform indicating the presence of the particulate matter is a noise component waveform. There was a problem of being buried inside.

Japanese Patent Publication No.3-334021 Japanese Patent Publication No. 5-14222 JP-A-10-185839

  Accordingly, an object of the present invention is to provide a method and an apparatus for accurately detecting even a minute conductive particle substance having a size of about 50 μm in a sheet-like electric material.

  The present invention has been made to solve the above-mentioned problems. The invention according to claim 1 is a microwave that transmits two slitted waveguides through which a sheet-like electric material having a ridge-shaped cross section passes. Are arranged side by side so as not to interfere with each other, and both the waveguides with slits are arranged at right angles to the transport direction of the sheet-like electrical material, and a transducer and a reflected wave are respectively provided at both ends of each waveguide with slits. Microwaves output from a microwave oscillator through a T-type circulator having a function of deflecting by 90 ° and a PIN diode switch are alternately incident, and a traveling wave is deflected by 90 ° through the T-type circulator. Is incident on the non-reflective terminator via the stub adjuster and the stub adjuster connected to the main line side, and is generated by the characteristic (impedance) of the stub adjuster. The generated reflected wave is incident on the slit waveguide through the porous directional coupler and the T-shaped circulator, and the detected wave is connected to the sub-line side of the porous directional coupler. The base noise signal is reduced by the two-signal processing circuit for the analog detection signal of each detector for each waveguide with a slit, and then the analog detection signal is input by the high-speed data acquisition circuit. In addition to A / D conversion, FIR filter operation is performed to obtain a digital signal with reduced noise, and the result and a detection position signal from the conductive particle substance position detection means are input to a computer and stored in a computer history file. Conductive particulate matter detection in sheet-like electrical materials characterized by storing and displaying the presence of conductive particulate matter on the display screen It is a method.

  The invention according to claim 2 is the invention according to claim 1, wherein the computer performs an extraction operation of a characteristic waveform generated by the presence of the conductive particulate material by wavelet transform, and then performs a neutral network operation. The characteristic waveform and the remaining noise waveform are separated, and only the characteristic waveform of the conductive particle substance is extracted to generate an alarm output. Is the method.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the conductive property includes a rotary encoder and a photoelectric sensor that reads a reference point or a junction point of the sheet-like electrical material in the sheet-like electrical material transfer line. Based on the detection signals, the distance from the reference point or joint point of the sheet-like electrical material to the position where the conductive particulate matter is detected is based on the pulse signal of the rotary encoder. A method for detecting a conductive particle substance in a sheet-like electric material, characterized in that the calculation is performed by the computer and is stored in a history file of the computer and simultaneously displayed on the display screen.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the waveguide with a slit through which the sheet-like electric material is passed is matched to the width of the sheet-like electric material, and only the upper part is formed. A method for detecting a conductive particulate material in a sheet-like electrical material, wherein the method is configured to divide into two so as to be able to move up and down, and to allow the joint portion of the sheet-like electrical material to pass through the waveguide portion without hindrance.

  According to a fifth aspect of the present invention, in the sheet-like electric material according to any one of the first to fourth aspects, the oscillation frequency of the microwave oscillator is different for each waveguide with a slit. This is a conductive particle substance detection method.

  According to the sixth aspect of the present invention, two waveguides with slits through which the sheet-like electric material having a ridge-shaped cross section passes are arranged in parallel so that the transmitted microwaves do not interfere with each other. Through a T-type circulator and a PIN diode switch having a function of deflecting the transducer and the reflected wave by 90 ° at both ends of each slit waveguide, respectively. A microwave oscillator is connected, and a porous directional coupler is connected to the reflected wave output side of the T-type circulator connected to both ends of each waveguide with slits, and the output side of the porous directional coupler. A non-reflective terminator is connected to the main line side via a stub adjuster, and a detector is connected to the sub-line side of the porous directional coupler via a low noise amplifier. In both cases, each detector for each waveguide with a slit is connected to a high-speed data acquisition circuit via a two-signal processing circuit, and a rotary provided on the output terminal of the high-speed data acquisition circuit and a sheet-like electric material transfer line. An apparatus for detecting conductive particulate matter in a sheet-like electrical material, wherein an encoder and each detection signal output terminal of a photoelectric sensor that reads a reference point or a junction point of the sheet-like electrical material are connected to an input terminal of a computer .

  In the present invention, waveguides with slits for passing two series of sheet-like electrical materials are provided by being shifted by λs / 4, and the waveguides with slits are juxtaposed at right angles to the transport direction of the sheet-like electrical materials. Based on the wavelength of the voltage standing wave generated in the slit waveguide, the positional relationship between the wave standing points of the voltage standing wave generated in the mutual waveguide is relative to the width direction of the sheet-like electrical material. Since the two waveguides with slits are arranged so as to be intermittently scattered at a narrow interval, the detection probability can be improved.

  In the present invention, a detector is connected to the sub-line side of the porous directional coupler via a low noise amplifier, and the load impedance of the terminal is varied on the main line side of the porous directional coupler. Since the non-reflective terminator that absorbs microwave power is connected via the stub adjuster, the voltage strength of the voltage standing wave is increased by adjusting the stub adjuster so as to increase the reflection coefficient of the voltage standing wave. Thus, the detection sensitivity can be increased.

  In addition, the present invention has a ridge-shaped cross-sectional structure of a slitted waveguide through which a sheet-like electrical material passes, shortens the in-tube wavelength of the voltage standing wave, and maximizes the voltage amplitude intensity (antinode) The detection probability can be improved by devising to increase the number of.

  In the present invention, the microwave output from the microwave oscillator is alternately switched using a PIN diode switch, and the transducers and the T-shaped circulator are alternately connected to both ends of the waveguide with slits. While maintaining the correlation with the traveling speed of the sheet-like electrical material, the two microwave standing waves with moderately different phases are switched alternately at high speed (μsec order). It can be generated and detected uniformly in the width direction of the sheet-like electric material.

  Moreover, after the A / D conversion of the detection signal by the high-speed data acquisition circuit as the first stage, the FIR filter operation is performed to reduce the base noise, and as the second stage, by the conductive particle material by the wavelet conversion by the computer. Performs an extraction calculation of the generated characteristic waveform, and then separates the characteristic waveform from the remaining noise waveform by a neural network calculation to extract only the characteristic waveform of the conductive particle material and generate an alarm output. Can be made.

  In addition, a rotary encoder and a photoelectric sensor that reads a reference point or a junction point of the sheet-like electrical material are provided in the sheet-like electrical material transfer line, and conductive particles are connected from the junction point of the sheet-like electrical material based on each detection signal. The distance to the position where the substance is detected can be calculated by a computer, saved in a computer history file, and simultaneously displayed on the screen.

  In addition, the waveguide with a slit through which the sheet-like electric material passes is divided into two so that only the upper part can be raised and lowered with the axis as a boundary according to the width of the sheet-like electric material, so that it is processed into a convex shape. The joint portion of the sheet-like electric material that may be able to pass through the waveguide portion without any trouble can provide a user-friendly device.

  Based on the above configuration and effects, conductive particle substances that are inherently or adhering to the sheet-like electrical material can be detected reliably and uniformly in the width direction as well as the sheet-like electrical material transfer direction. And a highly reliable detection device can be provided. The detection accuracy is, for example, a conductivity of about 50 μm in the case of a lithium ion battery separator (thickness is about 200 μm, travel speed is 10 m / min). Particulate matter can be reliably detected.

1 is a block diagram showing the configuration of Embodiment 1 of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional structure used for Example 1 of this invention is explanatory drawing which shows the basic composition of a waveguide with a ridge type slit. The top view of the waveguide with a slit used for Example 1 of the present invention. It is a front view of the waveguide with a slit used for Example 1 of the present invention, (a) shows the state where the upper part was lowered and (b) shows the state where the upper part was raised. The perspective view which shows the cross-section of the waveguide with a slit used for this invention Example 1. FIG. The wave form diagram which shows the positional relationship of the voltage standing wave which generate | occur | produces in the lines A and B of Example 1 of this invention. The figure which shows the detection performance test result at the time of using the prepreg as a sample with the apparatus shown in Example 1 of this invention. The figure which shows the detection performance test result at the time of using the nonwoven fabric as a sample with the apparatus shown in Example 1 of this invention.

  The present invention uses a method of generating a voltage standing wave by interference between a microwave incident wave and a reflected wave, and is made by paying attention to the fact that the reflection coefficient changes by changing the load impedance. is there.

  FIG. 1 is a block diagram illustrating a configuration of a conductive particulate matter detection device that is Embodiment 1 of the present invention. In FIG. 1, the two lines A and B on the upper and lower sides have the same configuration. Therefore, the following description is based on the line A.

  In FIG. 1, 1a is a microwave oscillator that oscillates a microwave of 8.2 to 12.4 GHz, for example, 9.4 GHz. The oscillated microwave is amplified to about 30 dB by the power amplifier 2a. The PIN diode switch 3a operating on the order of μsec is alternately switched to the lines R1 and L1 for transmission.

  The traveling wave of the microwave transmitted to the line R1 is supplied to the right side of the waveguide 11a with a slit via the transducer 4ar and the T-shaped circulator 5ar. The microwave that has passed through the slit-equipped waveguide 11a is bent 90 degrees by the action of the T-shaped circulator 5al installed on the opposite side, passes through the porous directional coupler 6al, and is coupled to the main line. It arrives at the non-reflective terminator 8al via the stub type adjuster 7al.

  The reflected wave generated by the action of the characteristic impedance of the stub adjuster 7al is incident on the slit-equipped waveguide 11a through the porous directional coupler 6al and the T-shaped circulator 5al, and is standing by the interference with the incident wave. Form. On the other hand, the detection wave (Doppler wave) generated by the presence of the conductive particulate matter is detected by being incident on the detector 10ar via the right T-circulator 5ar, the porous directional coupler 6ar, and the low noise amplifier 9ar. Is transmitted to the two-signal arithmetic processing circuit 12a.

  On the other hand, the microwaves transmitted to the line L1 by the switching operation of the PIN diode switch 3a are transmitted in the same order as described above, and finally detected by the detector 10al and transmitted to the two-signal processing circuit 12a.

  The two detection waves respectively output from the two-signal processing circuits 12a and 12b of the lines A and B are A / D converted by the high-speed data acquisition circuit 13, and also a digital signal in which noise is reduced by FIR filter calculation. The computer 14 performs mathematical operation processing to separate only the signal of the characteristic waveform generated by the intervention of the conductive particulate material, and finally stores it in the detection history file of the computer 14 by the alarm transmission circuit 15. Output alarm output to the outside.

  At the same time, based on the output signal from the photoelectric sensor 17 that reads the reference point or the junction point of the rotary encoder 16 and the sheet-like electric material 18 provided in the transfer line of the sheet-like electric material 18, the sheet-like electric material 18. The distance from the reference point or junction point to the position where the conductive particulate material is detected and the time when the detection wave is emitted are simultaneously stored in the history file of the computer 14 and also displayed on the display 14a.

  In the embodiment of the present invention, as shown in FIG. 1, the distance d between the axes of the waveguides 11a and 11b with slits is determined within a range in which the microwaves transmitted to both waveguides with slits do not interfere with each other. It is. That is, about 50-100 mm is desirable, for example, it is set to 60 mm. Further, as shown in FIG. 2, the sheet-like electrical material 18 is set with the sectional dimensions of the waveguides 11a and 11b with slits set to a = 22.9 mm, b = 10.2 mm, a ′ = 10 mm, b ′ = 2.0 mm. However, it is desirable that the dimension be such that the microwave does not leak to the outside without contacting the waveguide due to vibration during traveling, for example, e = 4 mm.

  In the present invention, the stub adjuster 7ar that can change the load impedance before the traveling wave of the microwaves passes through the slit waveguides 11a and 11b and arrives at the non-reflective terminators 8ar, 8al, 8br, and 8bl. 7al, 7br, 7bl, the reflection coefficient is maximized, and the voltage amplitude intensity at the antinode of the voltage standing wave is set to be large, so that the detection sensitivity can be increased.

  In the present invention, since the cross-sectional form of the waveguides 11a and 11b with slits is a ridge shape, the wavelength λg of the voltage standing wave (in-tube wavelength) is about λg≈34 mm when the oscillation frequency is 9.4 GHz. For example, when using WRI-10 (a = 22.9 mm, b = 10.2 mm) and using an oscillation frequency of 9.4 GHz, the voltage standing wave (in-tube wavelength) λg ′ is λg ′. When a waveguide with a ridge-shaped slit is used, the wavelength is shortened by approximately 22.7%, and the number of antinodes of the voltage standing wave increases accordingly, and the detection probability is improved.

  Furthermore, in the present invention, the microwave output from the microwave oscillator 1a is transmitted to the PIN diode switch 3a via the power amplifier 2a. The PIN diode switch 3a is switched by a control signal corresponding to a switching time (Δθ) set based on the correlation with the traveling speed of the sheet-like electrical material 18 output from the TTL circuit 18a. As a result of this operation, as shown in FIG. 6, the transfer of the R1ch and L1ch of the line A is shifted by Δf, so that a voltage having a phase difference of Δf is applied to the waveguide with slits corresponding to the switching time (Δθ). Standing waves can be generated.

  FIG. 6 illustrates the positional relationship in which the voltage standing waves of the lines A and B are generated in the present invention. If the length between the waveguide 11a with a slit and the T-shaped circulator 5ar and the length between the waveguide 11b with a slit and the T-shaped circulator 5br are designed to be different by Δf, microwave transmission from the lines R1 and L1 is possible. The phases of the two voltage standing waves generated in the slit-equipped waveguide 11a can be generated by being shifted by Δf. In FIG. 6, the phases of R1ch and L1ch of line A are shifted by Δf. The phase of R2ch and L2ch of line B is also shifted by Δf as in the case of line A. On the other hand, in the present invention, the voltage standing waves of the lines A and B are waved in the major axis direction of both lines by arranging the waveguides 11a and 11b with slits so as to be shifted by λg / 4. The high-sensitivity detection width (ΔS1) with the antinode as the boundary is distributed evenly at a small interval in the width direction of the sheet-like electrical material 18, and the width of the sheet-like electrical material is uniformly distributed. Can be detected.

  When the particle size of the conductive particle substance intervening in the sheet-like electric material 18 is about 80 μm or less, the detection signal waveform generated due to the presence of the conductive particle substance is the above-described physical, electrical, etc. Normally, it is buried in the noise waveform generated by the above factors.

  Therefore, in the present invention, the original signal transmitted from the two signal processing circuits 12a and 12b of the lines A and B is A / D converted by the high-speed data collection circuit 13, and then subjected to FIR filter calculation to reduce the base noise. Is sent to the computer 14.

  The computer 14 includes a wavelet transform for extracting a feature waveform generated by the presence of the conductive particulate material, a neural network operation for separating the feature waveform and the noise waveform, and a logical product operation for ensuring the accuracy of the operation process. Dedicated software for installing is installed.

  Based on the signals from the rotary encoder 16 and the photoelectric sensor 17 provided in the transfer line of the sheet-like electric material 18, the distance from the reference point or the junction point of the sheet-like electric material 18 to the position where the conductive particle substance is detected; The occurrence time is calculated and saved in the history file of the computer 14 and simultaneously displayed on the display 14a.

  In the apparatus of the embodiment, as shown in FIGS. 3 to 5, the waveguides 11 a and 11 a with slits are integrally formed (composite type), and guided with slits according to the width dimension of the sheet-like electrical material 18. The upper part of the wave tubes 11a and 11b can be moved up and down by about 50 mm by operating the air cylinder 19 with the axis as the boundary. By attaching this mechanism, when the sheet-like electric material 18 is continuously inspected for each roll unit, the protruding joint portion can pass through the slit waveguides 11a and 11b without any trouble. it can.

  Although the first embodiment has been described in detail, the present invention is not limited to this embodiment, and other changes and modifications can be made as in the second embodiment.

  Although the second embodiment is not illustrated, in the first embodiment, the microwave oscillators 1a and 1b are provided with two types of microwave oscillators of 9.4 GHz and 12 GHz, for example, and transmit microwaves having different wavelengths. This makes it possible to form two voltage standing waves having different wavelengths in the waveguides 11a and 11b with slits.

  For example, a voltage standing wave is formed by the interference of only the traveling wave of the microwave having the same frequency supplied to both sides of the waveguides 11a and 11b with slits, or the frequency and slit supplied to the waveguide 11a with slits. The frequency supplied to the attached waveguide 11b may be made different.

  By having such a configuration, not only the traveling direction of the sheet-like electrical material 18 but also the width direction can be detected uniformly, and at the same time, malfunctions caused by unnecessary noise waveforms can be eliminated. Thus, for example, it is possible to reliably detect a conductive particulate material having a particle size of up to about 50 μm.

  An example of the detection performance test by the embodiment apparatus of the present invention is shown in FIGS.

  The detection performance test data shown in FIG. 7 is based on conditions in which a prepreg is used as a sheet-like electric material, a running speed is 10 m / min, and a pseudo metal sample (copper, particle size of about 82 μm) is attached to the surface of the material. The actual data displayed on the display 14a when the pseudo metal sample is detected using the procedure of the wavelet transform and the neutral network. However, only L1ch is detected.

  The detection points of the analysis waveform (L1ch) in FIG. 7 are indicated by arrows. The time when this detection point occurs is also displayed at the bottom of FIG.

  The detection performance test data shown in FIG. 8 is based on the condition that a nonwoven fabric is used as the sheet-like electric material, the running speed is 10 m / min, and a pseudo metal sample (aluminum, particle size of about 70 μm) is attached to the surface of the material. The actual data displayed on the display 14a when the pseudo metal sample is detected using the procedure of the wavelet transform and the neural network. However, only R1ch is detected.

1a, 1b Microwave oscillators 2a, 2b Power amplifiers 3a, 3b PIN diode switches 4ar, 4al, 4br, 4bl Transducers 5ar, 5al, 5br, 5bl T-type circulators 6ar, 6al, 6br, 6bl Porous directional couplers 7ar, 7al, 7br, 7bl Sudb adjusters 8ar, 8al, 8br, 8bl Non-reflective terminators 9ar, 9al, 9br, 9bl Low noise amplifiers 10ar, 10al, 10br, 10bl detectors 11a, 11b Slit waveguides 12a, 12b 2 Signal processing circuit 13 High-speed data collection circuit 14 Computer 14a Display 15 Alarm transmission circuit 16 Rotary encoder 17 Photoelectric sensor 18 Sheet-like electrical material 18a, 18b TTL circuit 19 Air cylinder

Claims (6)

Two waveguides with slits through which the sheet-shaped electric material having a ridge-shaped cross section passes are arranged in parallel so that the transmitted microwaves do not interfere with each other, and both the waveguides with slits are transferred to the sheet-shaped electric material. Micros output from a microwave oscillator via a T-type circulator and a PIN diode switch which are arranged at right angles to the direction and have a function of deflecting the reflected wave and the reflected wave by 90 ° at both ends of each slit waveguide. Waves are incident alternately, the traveling wave is deflected by 90 ° via the T-shaped circulator, and incident on a non-reflective termination via a porous directional coupler and a stub adjuster connected to the main line side. The reflected wave generated by the characteristic (impedance) of the stub adjuster passes through the porous directional coupler and the T-shaped circulator. In addition, the detection wave is incident on the detector through a low noise amplifier connected to the sub-line side of the porous directional coupler, and each slit waveguide is A digital signal in which the analog detection signal of the detector is reduced in base noise signal by a two-signal processing circuit, and then the analog detection signal is A / D converted by a high-speed data acquisition circuit and FIR filter operation is performed to reduce noise. A signal, and a result of the detection and a position signal detected by the conductive particle substance position detection means are input to a computer and stored in a computer history file, and the presence of the conductive particle substance is displayed on the display screen. A method for detecting conductive particulate matter in a sheet-like electrical material. The computer performs an extraction operation of a feature waveform generated by the presence of the conductive particle substance by wavelet transform on the input signal, and then separates the feature waveform from the remaining noise waveform by a neutral network operation. 2. The method for detecting conductive particulate matter in a sheet-like electrical material according to claim 1, wherein only a characteristic waveform of the particulate matter is extracted to generate an alarm output. The sheet-like electric material transfer line is provided with a rotary encoder and a conductive particle substance position detection means consisting of a photoelectric sensor that reads the reference point or junction point of the sheet-like electric material. The computer calculates the distance from the reference point or joint point of the material to the position where the conductive particle substance is detected based on the pulse signal of the rotary encoder, and saves it in the computer history file while simultaneously displaying it on the display screen. 3. The method for detecting a conductive particulate material in a sheet-like electrical material according to claim 1 or 2, wherein the display is performed. The slit-like waveguide through which the sheet-like electrical material passes is divided into two so that only the upper part can be raised and lowered according to the width of the sheet-like electrical material, and the joint portion of the sheet-like electrical material has no trouble The method for detecting a conductive particulate material in a sheet-like electrical material according to any one of claims 1 to 3, wherein the material is allowed to pass therethrough. The method for detecting a conductive particle substance in a sheet-like electric material according to any one of claims 1 to 4, wherein the oscillation frequency of the microwave oscillator is different for each waveguide with a slit. Two waveguides with slits through which the sheet-shaped electric material having a ridge-shaped cross section passes are arranged in parallel so that the transmitted microwaves do not interfere with each other, and both the waveguides with slits are transferred to the sheet-shaped electric material. A microwave oscillator is connected via a T-type circulator and a PIN diode switch, which are arranged at right angles to the direction and have a function of deflecting the reflected wave by 90 ° at both ends of each slit waveguide, A porous directional coupler is connected to the reflected wave output side of each of the T-shaped circulators connected to both ends of each slit waveguide, and a stub adjuster is connected to the main line side on the output side of the porous directional coupler. A non-reflective terminator is connected to the sub-line side of the porous directional coupler, and a detector is connected to the sub-line side of the porous directional coupler via a low noise amplifier. Each detector for each tube is connected to a high-speed data acquisition circuit via a two-signal processing circuit, and a rotary encoder provided in the output terminal of the high-speed data acquisition circuit and a sheet-like electric material transfer line An apparatus for detecting a conductive particle substance in a sheet-like electric material, wherein each detection signal output terminal of a photoelectric sensor for reading a reference point or a junction point is connected to an input terminal of a computer.

Images