JP4176024B2 - Lithium leak detection device and lithium leak detection method - Google Patents

Description

  The present invention relates to a lithium leakage detection device and a lithium leakage detection method for detecting leakage of lithium in products using lithium as an electrolytic solution.

  Lithium and lithium compounds are widely used as battery electrolytes, but leakage is essential in products using lithium and lithium compounds because of their high reactivity and risk of corrosion and ignition.

In general, detection methods for elemental components such as lithium include ICP emission spectroscopic analysis and atomic absorption analysis. However, since the detection methods described above require pretreatment such as solution extraction, It is impossible to apply it directly at a site where a quick analysis is required (for example, see Non-Patent Document 1). X-ray fluorescence analysis is a technique capable of rapid analysis, but cannot detect lithium, which is a light element (see, for example, Non-Patent Document 2). Therefore, an effective lithium leak detection method has not yet been established, and the present situation is that only indirect lithium leak detection can be performed by detecting components other than lithium in the electrolytic solution.
Yoshikazu Muto et al. “Handbook of Analytical Instruments”, Chemical Newspaper, September 1980, p. 55 Yoshikazu Muto et al., “Analytical Instrument Manual”, Chemical Newspaper, September 1980, p. 113

  In recent years, with the increase in demand for lithium secondary batteries due to the spread of mobile phones and the like, improvement in inspection speed and reliability in production lines is required.

  However, as described above, the current method for detecting lithium and lithium compounds has only indirect lithium detection means for detecting components other than lithium in the electrolyte, and the volatile solvent leaked into the atmosphere from the electrolyte injection stage. There is a concern that the inspection speed and reliability may be insufficient due to the influence of components.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lithium leakage detection device and a lithium leakage detection method capable of detecting lithium and a lithium compound quickly and with high accuracy. To do.

In order to solve the above-described problems, a lithium leakage detection device according to the present invention includes a decompression container that contains an inspection object, an exhaust device that exhausts and decompresses the atmosphere in the decompression container, and a pulse on the surface of the inspection object. Irradiation means for converting the deposits on the surface into plasma by irradiating laser light, and detection means for detecting leakage of lithium and lithium compounds by spectroscopically analyzing light emitted from the generated plasma and detecting lithium-specific fluorescence By irradiating the surface of the object to be inspected with a laser beam having a spread behind the focal point, the substance adhering to the surface is evaporated to form a state of floating on the object surface. while not generated, in the condensing point, and characterized in that the floating substances are broken down, and configured to generate plasma Is shall.

Further, in order to solve the above-described problem, the lithium leakage detection method of the present invention adjusts the inside of the decompression container containing the inspection object to a decompressed atmosphere, and irradiates the surface of the inspection object with pulsed laser light. the deposit of the surface into a plasma, by detecting the lithium intrinsic fluorescence and spectroscopy emission from generated plasma, in Brighter lithium leak detection method to detect the leakage of lithium and lithium compounds, the test object By irradiating the surface with laser light that spreads behind the focal point, the substance adhering to the surface evaporates and forms a state of floating on the surface of the object, but the above-mentioned gathering point does not generate plasma on the surface In the method, the suspended substance is broken down to generate plasma .

  According to the lithium leakage detection apparatus and the lithium leakage detection method of the present invention, since leakage of lithium or a lithium compound from a product using lithium or a lithium compound is detected with high accuracy, the safety of the product is improved and the production yield is improved. Will improve.

  Embodiments of a lithium leakage detection method and apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of Embodiment 1 of the lithium leakage detection apparatus according to the present invention.

  The lithium leakage detection apparatus according to the first embodiment includes a controller 1 that controls each component device and data processing, a pulse laser oscillator 2 as an irradiating means, a spectroscope 3 that splits light emitted from plasma as a detecting means, and It is constituted by the detector 4.

  The laser beam 5 oscillated from the pulse laser oscillator 2 is reflected by the mirror 6, and the beam diameter is adjusted to a size that can cover the range in which leakage is desired to be detected by the lens 7, and the sample (object) 8 is irradiated. At this time, a plasma 9 of a surface adhering substance by ablation is generated at the laser irradiation position on the surface of the sample 8. The light emitted from the plasma 9 is collected by the lens 10 and is incident on the fiber 11. The light transmitted through the fiber 11 is split by the spectroscope 3 and measured by the detector 4.

  The fluorescence wavelength of lithium detected by the detector 4 is preferably 670.5 nm or 610.4 nm because the measurement sensitivity is increased. A specific example of the detector 4 includes a CCD camera. Further, when a gated CCD camera is used as the detector 4, it is possible to further increase the sensitivity of measurement by setting an appropriate photometric time. For example, when measuring the fluorescence from the lithium atom excitation level, the measurement time is set to a width of about 1 to 10 μs, which is slower than the pulsed laser beam, and when measuring the fluorescence from the lithium ion level, It is desirable to set it to about 1 to 3 μs, which is slower than the pulse laser beam.

  In the lithium leak detection apparatus of this embodiment, the sample 8 carried by the carrying device 12a is positioned on the measurement table 14 by the sample moving device 13. The measuring table 14 has a function of moving the sample so that the laser is irradiated to all the places where the sample 8 may leak.

  The controller 1 processes the signal detected by the detector 4 to determine the presence or absence of lithium. After the measurement is completed, the measurement result is displayed on the display device 15 and a command is issued from the controller 1 to the sample moving device 13 to detect the fluorescence of lithium atoms or ions, and the sample is moved to the defective product accumulation place 16. If it is not detected, it is sent to the next step.

  According to the lithium leakage detection apparatus of this embodiment, since the signal from lithium is directly detected, it is possible to detect the leakage of lithium more quickly and reliably than the indirect inspection method of the conventional method.

  A lithium leakage detection apparatus according to the second embodiment will be described with reference to FIG. In addition, about the common structure in the following each Example, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The lithium leakage detection apparatus of the second embodiment is designed to transmit only the fluorescence wavelength from lithium atoms or lithium ions in place of the spectrometer 3 and the detector 4 in the configuration of the lithium leakage detection apparatus of the first embodiment. The interference filter 17, the interference filter 18 that transmits only the background wavelength, and the detector 19 and the detector 20 that detect the light transmitted through each interference filter are applied.

  In the lithium leak detection apparatus of the present embodiment configured as described above, light emitted from the plasma 9 is guided in a parallel or converging manner by the condenser lens 21 and separated into two by the half mirror 22. One light is guided to the interference filter 17 designed to transmit only the fluorescence wavelength from lithium atoms or ions, and the other light is guided to the interference filter 18 transmitting only the background wavelength by the mirror 23. The light transmitted through the interference filter 17 and the interference filter 18 is detected by the detector 19 and the detector 20. Specific examples of the detector 19 and the detector 20 include a photomultiplier tube and a photodiode. The controller 1 compares signals from the detector 19 and the detector 20 to determine the presence or absence of lithium.

  According to the lithium leakage detection apparatus of the present embodiment, a cheaper and simple system configuration can be realized.

In the configuration of the lithium leakage detection apparatus according to the first embodiment and the second embodiment described above, the laser output density at the irradiation portion on the sample surface is set in the range of 1 MW / cm ² to 1 GW / cm ² .

  With this setting, it is possible to minimize damage to the base material due to laser light irradiation, and to excite and detect the surface-adhering substance with certainty.

  Next, a lithium leakage detection apparatus according to the third embodiment will be described with reference to FIG.

  In the lithium leakage detection apparatus of the fourth embodiment, the laser beam is separated into two laser beams 5a and 5b, and the respective cylindrical laser beams 24a are matched to the shape and size of the portion of the sample 8 to be measured. Then, it is shaped into a sheet by the cylindrical lens 24b and irradiated from two directions.

  The lithium leakage detection apparatus according to the third embodiment includes a detection unit including an interference filter 17a, an interference filter 18a, a detector 19a, and a detector 20a, and an interference filter 17b, an interference filter 18b, a detector 19b, and a detector 20b. A detection unit. As described above, the lithium leakage detection apparatus according to the third embodiment is configured to include two sets of detection units, whereby fluorescence generated from two locations can be simultaneously measured. Moreover, it is good also as a structure using two sets of the spectrometer 3 and the detector 4 which were described in Example 1 instead of the interference filter and the detector.

  According to the lithium leak detection apparatus of the present embodiment, the measurement range can be widened by performing measurement simultaneously from two directions, so that the measurement time can be shortened. Further, by shaping the laser beam into a sheet shape and limiting the irradiation range to a portion where measurement is desired, it is possible to reduce the influence of the laser beam on the base material such as irradiation marks and peeling of the coating.

  Next, a lithium leakage detection apparatus according to the fourth embodiment will be described with reference to FIG.

  The lithium leakage detection apparatus according to the fourth embodiment is configured to include beam expanding lenses 25a and 25b, a lens array 26, and a condensing lens 27 instead of the condensing lens 7 according to the first embodiment.

  FIG. 5 shows a configuration example of the lens array 26. FIG. 5A shows a structure in which two lens arrays 26 formed by laminating a plurality of small lenses 28a, which are cylindrical lenses, are attached in parallel, and these lens arrays 26 are arranged in different directions. It is. FIG. 5B shows a configuration example of the lens array 26 in which square small lenses 28b are combined, and FIG. 5C shows a configuration example of the lens array 26 using hexagonal small lenses 28c.

  In the lithium leakage detection apparatus of this embodiment configured as described above, the laser beam 5 is enlarged by the beam expanding lens 25a and the beam expanding lens 25b according to the aperture diameter of the lens array 26 and is incident on the lens array 26. To be separated into a plurality of beams. The separated beams are superimposed on the sample 8 by the condenser lens 27 and irradiated.

  In order to speed up the measurement time, it is necessary to take a wide irradiation area, but in this case, the signal intensity may be affected by the laser intensity distribution, and the location dependence of the plasma intensity may occur. is there. Therefore, according to the lithium leakage detection apparatus of the present embodiment, even laser light with non-uniform intensity distribution can be divided into minute areas and overlapped with the laser light to make the intensity distribution uniform, and plasma in the irradiation area The location dependence of strength can be reduced.

  Next, the lithium leak detection apparatus according to the fifth embodiment will be described with reference to FIG.

  In the lithium leakage detection apparatus of this embodiment, the laser beam 5 of the pulse laser oscillator 2 is magnified by the beam enlarging lens 29a and the beam enlarging lens 29b and reflected by the mirror 30, and the reflected light is transmitted through the lens array 31. The light passes through the dichroic mirror 32 and is collected again by the condenser lens 33. The optical fiber 34 transmits the laser light 5 onto the sample 8 and the plasma 9 to the spectroscope 3.

  In the lithium leakage detection device of Example 5 configured as described above, when the sample 8 conveyed by the conveying device 12a is positioned at the measurement position, the laser light transmitted by the optical fiber 34 is condensed by the lens 35. Irradiated. At this time, the generated light from the plasma 9 is condensed again by the lens 35 and returned to the optical fiber 34. The light transmitted by the optical fiber 34 is guided to the spectroscope 3 by the dichroic mirror 32 and the condenser lens 37.

  The optical fiber 34 and the lens 35 are driven by a driving device 36 so that the irradiation region of the laser beam 5 can cover the entire region to be measured. The controller 1 processes the signal detected by the detector 4 and determines the presence or absence of lithium. After a series of measurements is completed, the measurement result is displayed on the display device 15 and a command is issued from the controller 1 to the sample moving device 13 to detect the fluorescence of lithium atoms or ions. If not detected, the sample is sent to the next step.

  According to the lithium leak detection apparatus of the present embodiment, the apparatus configuration can be made simpler and more flexible by adopting a configuration in which transmission of laser light and plasma emission is performed by the same optical fiber.

  Next, a lithium leakage detection apparatus according to the sixth embodiment will be described with reference to FIG.

  The lithium leak detection apparatus according to the sixth embodiment includes a lens 38 that is designed so that the laser beam 5 is focused above the surface of the sample 8 instead of the lens 7 according to the first embodiment.

  In the lithium leakage detection apparatus of the present embodiment configured as described above, the sample 8 is irradiated with a beam having a spread behind the focal point, so that the energy density of the laser beam at the irradiated portion is lowered and the surface adheres. The material is evaporated, but no plasma is generated on the surface. At this time, the surface adhering substance evaporates and floats on the sample. For this reason, at the condensing point above the sample 8, the atmospheric gas and the evaporated substance 39 are broken down, and the plasma 40 is generated. The light emitted from the plasma 40 is collected and spectroscopically measured by the same configuration as in the first embodiment.

  According to the lithium leakage detection apparatus of the present embodiment, the energy density of the laser beam irradiated on the sample can be reduced, so that the influence of the laser beam on the base material, such as irradiation marks and peeling of the paint, can be reduced.

  A lithium leakage detection apparatus according to the seventh embodiment will be described with reference to FIG.

In the lithium leakage detection apparatus according to the seventh embodiment, the lens 38 according to the sixth embodiment is configured such that the laser beam 5 reflects the sample 8 and is focused above the surface.

  In the lithium leak detection apparatus of the present embodiment configured as described above, on the sample 8, since the laser beam 5 is in front of the focal point, the irradiation site is irradiated by irradiating in a low energy density state. No plasma is generated on the surface of the sample 8 even if the energy density of the laser beam 5 is reduced and the surface adhering substance evaporates. At this time, the surface adhering substance evaporates and floats above the sample 8. For this reason, at the condensing point above the sample 8, the atmospheric gas and the evaporated substance 39 are broken down to generate the plasma 40. The light emitted from the plasma 40 is collected and spectroscopically measured by the same method as in the seventh embodiment.

  According to the lithium leakage detection apparatus of the present embodiment, the energy density of the laser beam irradiated on the sample can be reduced, so that it is possible to reduce the influence of the laser beam on the base material, such as irradiation marks and paint peeling. is there.

  Next, a lithium leakage detection apparatus according to an eighth embodiment will be described with reference to FIG.

In the eighth embodiment, two pulse laser oscillators, that is, a pulse laser oscillator 2a and a pulse laser oscillator 2b are provided. The pulsed laser oscillator 2a is irradiated so that the energy on the surface of the sample 8 is 0.5 GW / cm ² or less, and the pulsed laser oscillator 2b is set so that the output is stably broken down. The laser beam 5d oscillated from the pulse laser oscillator 2b is set so as to be focused 1 mm above the sample surface, and is set so as to be irradiated with a delay of 1 μs from the laser beam 5c oscillated from the pulse laser oscillator 2a. To do.

  In the lithium leak detection apparatus of the present embodiment configured as described above, the surface adhering substance is evaporated by irradiating the sample 8 with the laser beam 5c from the pulse laser oscillator 2a. Since the energy density is low, plasma is not generated on the surface of the sample 8, and the surface adhering substance jumps out of the surface as fine particles of the evaporated substance 39 as shown in the figure. The speed at this time is generally about 1000 m / s, and the time to reach the condensing point 1 mm above is 1 μs. Therefore, when the laser beam 5c from the pulse laser oscillator 2b is condensed and irradiated above the sample 8 by the lens 27 with a delay of 1 μs, a breakdown plasma 40 due to the atmospheric gas or the evaporated substance 39 is generated. The emitted light from the plasma 40 is collected and spectroscopically measured by the same configuration as in the first embodiment.

  According to the lithium leakage detection apparatus of the present embodiment, the energy density of the laser beam irradiated on the sample can be reduced, so that it is possible to reduce the influence of the laser beam on the base material, such as irradiation marks and paint peeling. is there.

  Moreover, in the lithium leak detection apparatus of Examples 1 to 8, the wavelength of the laser beam 5 is set to a second harmonic of the Nd: YAG laser.

  In general, in the initial stage of plasma generation, the shorter the wavelength of laser light, the higher the excitation efficiency with less energy and the easier generation of plasma. Therefore, since the excitation efficiency is improved by setting the wavelength of the laser beam to be radiated to the second harmonic of the Nd: YAG laser, the laser intensity to be irradiated can be kept low, and the laser beam such as an irradiation mark or peeling of the coating can be reduced. The influence on the material can be reduced.

Further, for example, when the measurement object is lithium hexafluorophosphate (LiPF ₄ ) used as an electrolyte of a lithium ion secondary battery, the spectrum dispersed by the spectrometer 3 in Examples 1 to 8 Therefore, not only lithium but also fluorescence of phosphorus and fluorine is detected at the same time.

  According to the lithium leakage detection device having such a configuration, signals from a plurality of elements can be monitored simultaneously, and the reliability of the measurement result can be further improved.

  Next, the lithium leak detection apparatus according to the ninth embodiment will be described with reference to FIG.

  The lithium leakage detection device of this embodiment is configured to include a decompression vessel 41 and an exhaust device 42 in the previous stage of lithium measurement.

  In the lithium leakage detection apparatus of this embodiment configured as described above, one or a plurality of samples 8 are introduced into the decompression vessel 41 in advance before the measurement of the laser beam 5 and exhausted by the exhaust device 42. A reduced-pressure atmosphere is set, and then lithium is measured.

According to the lithium leak detection system of the present embodiment, once it solution leaky by placing the sample under vacuum atmosphere, to the interior of the components have not leaked under normal atmospheric pressure for defect portion is small Even when detection is difficult, the detection accuracy is improved because it is easy to detect lithium leakage.

  Next, the lithium leakage detection apparatus of Example 10 will be described with reference to FIG.

  The lithium leakage detection device of this embodiment includes a container 43 and an exhaust device 44, and measures lithium in the container 43.

  In the lithium leak detection apparatus of the present embodiment configured as described above, after the sample 8 is introduced into the container 43, the exhaust apparatus 44 is activated to make the inside of the container 43 in a reduced pressure atmosphere. That is, lithium is measured in a reduced pressure atmosphere.

According to the lithium leak detection system of the present embodiment, once it solution leaky by placing the sample under vacuum atmosphere, to the interior of the components have not leaked under normal atmospheric pressure for defect portion is small Even when detection is difficult, the detection accuracy is improved because it is easy to detect lithium leakage.

  Next, the lithium leakage detection apparatus of Example 11 will be described with reference to FIG.

  The lithium leak detection apparatus of this embodiment is configured to include a replacement gas injection mechanism including a gas cylinder 45 and a valve 46 in the container 43. As an example of the replacement gas, for example, when the analysis target is an electrolyte of a lithium ion secondary battery, the gas does not interfere with the fluorescence wavelengths of lithium, phosphorus, and fluorine.

  In the lithium leak detection apparatus of the present embodiment configured as described above, after the sample 8 is introduced into the container 43, it is evacuated by the exhaust device 44 and at the same time the valve 46 is opened to fill the container 43 with the replacement gas. That is, it is assumed that lithium is measured in a replacement gas atmosphere inside the container 43.

  According to the lithium leakage detection apparatus of this example, the solution is likely to leak once the sample is placed in a reduced-pressure atmosphere, and the internal components do not leak under normal atmospheric pressure due to the minute defect. Even when the detection is difficult, the detection accuracy is improved because it is easy to detect the lithium leakage.

  In the lithium leakage detection apparatus of the present invention, it is assumed that, for example, 670.8 nm and 610.4 nm wavelengths are simultaneously detected by the detector 4 as the fluorescence wavelength of lithium from the spectrum dispersed by the spectrometer 3.

  According to the lithium leak detection apparatus having such a configuration, it is possible to further improve the reliability of the measurement result by simultaneously monitoring signals of a plurality of wavelengths.

FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram showing a configuration example of an irradiation unit of the lithium leakage detection device of the present invention. (A), (B) and (C) are structural diagrams showing a configuration example of a lens array. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram showing a configuration example of an irradiation unit of the lithium leakage detection device of the present invention. FIG. 3 is a structural diagram showing a configuration example of an irradiation unit of the lithium leakage detection device of the present invention. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention. FIG. 3 is a structural diagram illustrating a configuration example of a lithium leakage detection apparatus according to the present invention.

Explanation of symbols

1 Controller 2 Pulse laser oscillator (irradiation means)
3 Spectrometer (detection means)
4 Detector (Detection means)
5 Laser light 6 Mirror 7 Condensing lens 8 Sample (object)
DESCRIPTION OF SYMBOLS 9 Breakdown plasma 10 Fluorescence condensing lens 11 Optical fiber 12a, 12b Sample conveyance apparatus 13 Sample movement apparatus 14 Measurement stand 15 Display apparatus 16 Defective goods accumulation place 17 Interference filter 18 Interference filter 19 Detector (detection means)
20 Detector (Detection means)
21 Condensing lens 22 Half mirror 23 Mirror 24a, 24b Cylindrical lens 25a, 25b Beam expanding lens 26 Lens array 27 Condensing lens 28a, 28b, 28c Small lens 29a, 29b Beam expanding lens 30 Mirror 31 Lens array 32 Dichroic mirror 33 Condensing lens 34 Optical fiber 35 Condensing lens 36 Driving device 37 Condensing lens 38 Condensing lens 39 Evaporating substance 40 Plasma 41 Depressurization vessel 42 Exhaust device 43 Container 44 Exhaust device 45 Gas cylinder 46 Valve

Claims (6)

A decompression container that contains the inspection object, an exhaust device that exhausts the atmosphere in the decompression container and decompresses, and an irradiation means that irradiates the surface of the inspection object with pulsed laser light to turn the deposit on the surface into plasma And detecting means for detecting leakage of lithium and a lithium compound by spectroscopically analyzing light emitted from the generated plasma and detecting lithium-specific fluorescence, and has a spread on the surface of the inspection object behind the focal point. By irradiating the laser beam, the substance adhering to the surface is evaporated to form a floating state on the surface of the object, but the surface does not generate plasma. And a lithium leakage detection device configured to generate plasma . ^2. The lithium leakage detection apparatus according to claim 1, wherein the energy density of the pulse laser beam irradiated from the irradiation unit on the sample surface is 1 MW / cm ² or more and 1 GW / cm ² or less. The lithium leakage detection apparatus according to claim 1, further comprising a cylindrical lens that shapes and irradiates a pulse laser beam from the irradiation unit according to the shape of the object. Condensing optics comprising a lens array arranged in parallel, separating the pulsed laser light from the irradiation means into a plurality of laser beams having different optical axes, and condensing the separated laser beams within a predetermined range on the surface of the object The lithium leakage detection device according to claim 1, further comprising a system. The lithium leak detection apparatus according to claim 1, further comprising an optical fiber that transmits a pulse laser beam from the irradiation unit and light emission from the plasma. The inside of the decompression container containing the inspection object is adjusted to a reduced pressure atmosphere, and the surface of the inspection object is irradiated with a pulse laser beam to turn the deposit on the surface into plasma, and the emission from the generated plasma is spectroscopically separated into lithium. by detecting intrinsic fluorescence, attached at Brighter lithium leak detection method to detect the leakage of lithium and lithium compounds, in the inspection object surface and the surface by irradiating a laser beam having a spread behind the focal point The material is evaporated to form a state of floating on the surface of the object, but the plasma is not generated on the surface. On the other hand, the floating material is broken down to generate plasma. A method for detecting lithium leakage.

Images