Porosity derivation method and porosity derivation device

Abstract

The problem to be solved by the present invention is to provide a porosity derivation method and a porosity derivation device capable of deducing the porosity of an object to be inspected during transport. To solve the above problem, the present invention provides a porosity derivation method, which is a method for deducing the porosity of an object to be inspected, and includes: a weight per unit area measurement step, which measures the weight per unit area of ​​a specific portion of the object to be inspected during transport; a thickness measurement step, which measures the thickness of the specific portion of the object to be inspected during transport; and a porosity derivation step, which deduces the porosity of the object to be inspected based on the weight per unit area, the thickness, and the true density of the object to be inspected.

Description

Technical Field

[0001] The invention relates to a porosity derivation method and a porosity derivation device. Background Art

[0002] Conventionally, the porosity of an object under inspection has been measured. For example, a method for measuring the porosity of a solid electrolyte filled with an electrolyte is known in which the porosity is measured using an image obtained by photographing a cross-section of the solid electrolyte using image analysis software (see Patent Document 1).

[0003] [Prior technical literature]

[0004] (Patent Document)

[0005] Patent Document 1: International Publication No. 2018 / 186442 Summary of the Invention

[0006] [Problems to be solved by the invention]

[0007] The porosity measurement method described in Patent Document 1 requires cutting a sample and then photographing the cross-section. Therefore, when this method is applied on a production line, spot checks are required. This can lead to failure to detect defective products and an increase in defective products due to slow feedback. Therefore, there is a desire to develop a method for inferring the porosity of an inspected object while it is being transported.

[0008] The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a porosity estimating method and a porosity estimating device capable of deriving the porosity of an inspection object being transported.

[0009] [Technical means to solve the problem]

[0010] (1) The present invention relates to a porosity derivation method, which is a method for deriving the porosity of an object to be inspected, and comprises: a unit area weight measuring step, which measures the unit area weight of a specific portion of the object to be inspected during transportation; a thickness measuring step, which measures the thickness of the specific portion of the object to be inspected during transportation; and a porosity derivation step, which deduces the porosity of the object to be inspected based on the unit area weight, the thickness, and the true density of the object to be inspected.

[0011] According to the invention of (1), a porosity estimating method capable of estimating the porosity of an inspection object during transportation can be provided.

[0012] (2) The porosity derivation method according to (1), wherein the object to be inspected is a substrate filled with a filler, the unit area weight measuring step measures the unit area weight of the substrate and the filler, and the porosity derivation step deduces the porosity of the object to be inspected based on the unit area weight of the substrate and the filler, the thickness of the object to be inspected, and the true density of the substrate and the filler.

[0013] According to the invention of (2), a porosity estimating method capable of estimating the porosity of a base material filled with a filler during transportation can be provided.

[0014] (3) The porosity derivation method according to (2), wherein the filler is an electrolyte.

[0015] According to the invention of (3), the porosity of the electrolyte layer used as a battery material can be derived.

[0016] (4) Furthermore, the present invention relates to a porosity derivation device, comprising: a transport unit for transporting an object to be inspected; a unit area weight measuring unit for measuring the unit area weight of a specific portion of the object to be inspected during transport; a thickness measuring unit for measuring the thickness of the specific portion of the object to be inspected during transport; a storage unit for storing the true density of the object to be inspected; and a derivation unit for derivation of the porosity of the object to be inspected based on the unit area weight, the thickness, and the true density of the object to be inspected.

[0017] According to the invention of (4), a porosity estimating device capable of estimating the porosity of an inspection object being transported can be provided.

[0018] (5) A porosity derivation device according to (4), wherein the object to be inspected is a substrate filled with a filler, the unit area weight measuring unit measures the unit area weight of the substrate and the filler, the storage unit stores the true density of the filler and the substrate, and the derivation unit deduces the porosity of the object to be inspected based on the unit area weight of the substrate and the filler, the thickness of the object to be inspected, and the true density of the substrate and the filler.

[0019] According to the invention of (5), a porosity estimating device capable of estimating the porosity of a base material filled with a filler during transportation can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A This is a conceptual cross-sectional view of an inspection object that is the subject of the porosity derivation method according to the embodiment.

[0021] Figure 1B is used according to Figure 1AConceptual cross-section of the derivation method used to derive porosity.

[0022] Figure 2 Schematic diagram showing a porosity derivation device according to an embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment.

[0024] <Porosity Derivation Method>

[0025] The porosity derivation method of this embodiment is a method for derivation of the porosity of an inspection object, and is capable of derivation of the porosity of an inspection object while in transit. The porosity derivation method includes: a weight per unit area measurement step, which measures the weight per unit area of ​​a specific portion of the inspection object while in transit; a thickness measurement step, which measures the thickness of the specific portion of the inspection object while in transit; and a porosity derivation step, which deduces the porosity of the substrate based on the measured parameters and the true density of the inspection object.

[0026] (Measurement procedure of unit area weight)

[0027] The unit area weight measuring step is to measure the unit area weight (g / m2) of a specific portion of the above-mentioned inspection object during transportation. 2 ) is measured. The method for measuring the weight per unit area is not particularly limited as long as it is a method that can measure the object to be inspected during transportation, and an example thereof is the fluorescent X-ray detection method. The fluorescent X-ray detection method first irradiates the object to be inspected as the measurement object with X-rays, thereby causing the atoms constituting the object to be inspected to be excited. Then, by detecting the fluorescent X-rays generated when the atoms return to a stable state from the excited state, the weight per unit area of ​​the object to be inspected, such as the base material and the filler, can be measured separately. Based on the detection results of the fluorescent X-rays, different energy intensities are obtained for each element, and the weight per unit area of ​​the object to be inspected can be calculated based on the energy intensities. Furthermore, according to the above-mentioned method using fluorescent X-rays, the weight per unit area of ​​the object to be inspected as the measurement object can be measured in a non-contact manner, and therefore, the weight per unit area of ​​the object to be inspected during transportation can be measured. As other methods for measuring the weight per unit area, the following method can be mentioned: irradiating the object to be inspected as the measurement object with radiation such as beta rays and measuring the amount of radiation transmitted.

[0028] (Thickness measurement procedure)

[0029] The thickness measurement step is a step of measuring the thickness of a specific portion of the above-mentioned object to be inspected during transportation. As a method for measuring thickness, there is no particular limitation as long as it is a method that can measure the object to be inspected during transportation, and examples thereof include methods using spectral interferometry laser displacement measurement. The method using spectral interferometry laser displacement measurement is, for example, the following method: a pair of sensors are arranged on both sides of the object to be inspected in the thickness direction, the object to be inspected is irradiated with light containing various wavelengths, and the phase difference between the reflected light and the emitted light is measured, thereby measuring the distance from the sensor to the object to be inspected and calculating the thickness of the object to be inspected. As other thickness measurement methods, measurement methods using ultrasonic waves and the like can also be listed, but from the viewpoint of measuring the object to be inspected with high precision, the method using spectral interferometry laser displacement measurement is preferred.

[0030] The specific portion of the inspection object filled with the filler in the weight measurement step and the specific portion of the inspection object in which the filler is filled, which serves as the measurement location in the thickness measurement step, are synchronized. Methods for synchronizing the measurement locations in the weight measurement step and the thickness measurement step include, for example, recording the coordinates of the position measured by the weight measurement device and instructing the thickness measurement device to measure the same position.

[0031] (Porosity derivation steps)

[0032] The porosity derivation step is a step for deriving porosity based on the weight per unit area measured in the weight per unit area measurement step, the thickness measured in the thickness measurement step, and the true density of the inspection object, such as the substrate and filler. The porosity in this embodiment represents the ratio (%) of the volume of pores in the substrate to the volume of the filler in the substrate. The following describes the porosity derivation method using a solid electrolyte sheet as an example of a substrate that is a filler in the inspection object.

[0033] Figure 1A This is a conceptual cross-sectional diagram showing the structure of a solid electrolyte sheet B, which is a nonwoven fabric sheet serving as a base material and filled with a solid electrolyte. As shown in Figure 1, the solid electrolyte sheet B comprises a solid electrolyte layer S and a nonwoven fabric layer Nw. The nonwoven fabric layer Nw is filled with a solid electrolyte. Numerous pores V exist within the solid electrolyte layer S. Assuming that N pores with a volume of v1 exist within a filler with a volume of V, the porosity can be calculated using the following equation (1).

[0034] Porosity [%] = (N × v1) / V × 100 (1)

[0035] Here, assuming that the pores existing in the base material are laminated with a thickness of h on one end side of the filler having a thickness of H, the porosity in the above formula (1) is equal to the ratio of the thickness h to the thickness H.

[0036] Figure 1B It is shown that, assuming that the solid electrolyte sheet B is sequentially and individually Figure 1A Schematic diagram of the thickness of each layer when the pores V, solid electrolyte layer S and non-woven fabric layer Nw are laminated. Figure 1B As shown, the thickness H represents the thickness of the solid electrolyte sheet B as a whole. The thickness h1 represents the thickness of the solid electrolyte layer S, and the thickness h2 represents the actual thickness of the non-woven fabric layer Nw as a substrate, which only includes non-woven fabric. The porosity to be derived is the volume ratio of the pores included in the solid electrolyte as a filler. Therefore, the porosity is the thickness obtained by subtracting the actual thickness h2 of the non-woven fabric layer Nw as a substrate from the thickness H of the sheet B as a whole ( Figure 1B The thickness of the pore V is derived from H1 in the equation (2). Specifically, the porosity is derived using the following equation (2). Furthermore, when the object to be inspected does not have a substrate such as a nonwoven fabric Nw, and is composed solely of a solid electrolyte S, for example, the thickness h2 in the equation (2) is 0.

[0037] Porosity [%] = {1-h1 / (H-h2)} × 100(2)

[0038] Here, the thickness H in the above formula (2) is the thickness of the specific portion of the substrate filled with the filler measured in the thickness measurement step. The thickness h1 can be used as the thickness of the specific portion, and the unit area weight (g / m2) of the specific portion of the solid electrolyte S measured in the unit area weight measurement step can be used as the unit area weight (g / m2) of the solid electrolyte S measured in the unit area weight measurement step. 2 ), and the true density (g / m 3 The thickness h2 can also be calculated as the thickness of a specific portion by obtaining the true density of the nonwoven fabric Nw as the base material in advance.

[0039] According to the porosity estimating method of the present embodiment, the porosity of a substrate as an inspection object being conveyed can be estimated with high accuracy in a non-contact manner.

[0040] <Subject>

[0041] The inspected object of this embodiment is not particularly limited, and the following inspected objects can be cited: for example, a substrate composed of a porous body that can be filled with a filler. In addition, the inspected object of the porosity derivation method of this embodiment may not have the above-mentioned substrate. For example, the porosity derivation method of this embodiment can also be applied to an inspected object composed only of an electrolyte as a filler as exemplified below. The above-mentioned inspected object may also have Figure 1A The component has a sheet-like shape as shown.

[0042] (Base material)

[0043] The substrate of the object to be inspected in the porosity derivation method of this embodiment is not particularly limited as long as it has pores that can be filled with fillers. The filler filled in the substrate is an electrolyte such as the following solid electrolyte. When the substrate filled with the filler is used as a solid electrolyte sheet, the substrate is preferably in the shape of a non-woven fabric. Thus, it is easy to meet the preferred porosity or thickness of the solid electrolyte layer. The shape of the substrate can also be a woven shape, a porous shape, etc. In addition to the above, when the substrate filled with the filler is used as an electrode collector of a lithium-ion secondary battery, etc., the substrate can also be a metal porous body such as foam metal.

[0044] The material of the substrate is not particularly limited. Examples of the material used as the substrate of the solid electrolyte layer include polyethylene terephthalate, nylon, aromatic polyamide, Al2O3, glass, etc. In addition to the above, examples of the material used as the substrate of the electrode current collector include porous metals such as copper, aluminum, and SUS.

[0045] (filler)

[0046] As the filler filled in the substrate of the present embodiment, there is no particular limitation. When the substrate filled with the filler is used as an electrolyte sheet of a lithium ion secondary battery, etc., as the electrolyte filled, for example, sulfide solid electrolyte materials, oxide solid electrolyte materials, nitride solid electrolyte materials, halide solid electrolyte materials, etc. can be listed. In addition to the above, the electrolyte filled can also be a well-known liquid electrolyte or gel electrolyte for a liquid type battery. When the substrate filled with the filler is used as an electrode collector of a lithium ion secondary battery, etc., as the filler filled, an electrode composite material such as a negative electrode composite material or a positive electrode composite material can be listed.

[0047] There is no particular limitation on the method of filling the filler into the substrate, and the filling method can be selected according to the type of substrate and filler. The following methods can be cited: for example, a slurry is applied to a substrate in the shape of a non-woven fabric and dried, wherein the slurry is prepared by dissolving or dispersing a solid electrolyte in a solvent. As a coating method, for example, methods using slide die coating, comma blade die coating, comma blade reverse die coating, gravure coating, gravure reverse coating, etc. can be cited. As a drying method, for example, a method using a drying device such as hot air, a heater, or high frequency can be cited. After drying, sheet press or roller pressing can also be used for pressurization to improve strength and density.

[0048] The thickness and porosity of the filler-filled substrate are not particularly limited. However, when the filler-filled substrate is used as an electrolyte sheet for a lithium-ion secondary battery, for example, there is an optimal porosity for the substrate from the perspective of suppressing a decrease in ion conductivity.

[0049] Porosity Derivation Device

[0050] The porosity derivation device of this embodiment is a device that can derive the porosity of an object to be inspected during transportation. The object to be inspected can be a base material filled with a filler or an object to be inspected without a base material. Figure 2 As shown, the porosity derivation device 1 includes a transport unit 2, a basis weight measurement unit 30, a thickness measurement unit 40, and a functional unit 50 having a storage unit 51 and a derivation unit 52. The functional unit 50 is communicably connected to a server device 60 via a network NW.

[0051] The transport unit 2 is not particularly limited, and a well-known transport device capable of transporting the inspection object B at a specific transport speed, such as a belt conveyor capable of transporting the inspection object B, can be used.

[0052] (Weight per unit area measurement unit)

[0053] The basis weight measuring unit 30 is not particularly limited, and any well-known device capable of non-contactly measuring the basis weight of the inspection object B, such as a fluorescent X-ray detector or a beta-ray thickness gauge, can be used. When the inspection object B is a base material filled with a filler, the basis weight measuring unit 30 is preferably capable of separately measuring the basis weights of the base material and the filler.

[0054] (Thickness measurement unit)

[0055] The thickness measuring unit 40 is not particularly limited, and a well-known device capable of measuring the distance to an object in a non-contact manner, such as a spectral interference laser displacement measuring device using laser light, which is focused light such as visible light, ultraviolet light, and infrared light, can be used.

[0056] (Functional Department)

[0057] The functional unit 50 has a storage unit 51 and a derivation unit 52. In addition to the above, the functional unit 50 also has: an input unit for the user of the porosity derivation device 1 to input various information such as the true density of the inspected object such as the base material and the filler; and an output unit that can output the porosity derived by the derivation unit 52. In addition to the above, the functional unit 50 may also include a judgment unit, which judges whether the porosity derived by the derivation unit 52 is within a specific numerical range. The functional unit 50 is communicatively connected to the unit area weight measuring unit 30 and the thickness measuring unit 40 using wired or wireless communication means, and is communicatively connected to the server device 60 via the network NW. The functional unit 50 is not particularly limited, and can be implemented by, for example, a storage device such as a memory or a hard disk, a computing device such as a central processing unit (CPU), a display device, and the like.

[0058] (Storage Department)

[0059] The storage unit 51 stores pre-entered true densities of the inspection object, such as the base material and filler. Furthermore, the storage unit 51 also stores the calculation formula for deriving porosity, as described above, and a program for executing the calculation formula. In addition to the above, the storage unit 51 also stores the coordinates of the measurement position of the inspection object B, as measured by the weight measurement unit 30 and the thickness measurement unit 40, and the measured weight or thickness values.

[0060] (Derivation Department)

[0061] The derivation unit 52 deduces the porosity according to the calculation formula for deducing porosity described above based on the true density of the base material and the true density of the filler stored in the storage unit 51, and the measured values ​​of the unit area weight or thickness of the inspected object B measured by the unit area measuring unit 30 and the thickness measuring unit 40.

[0062] The following briefly describes the procedure for measuring the porosity of the inspection object B using the porosity derivation device 1 having the above-described structure. First, the weight per unit area measuring unit 30 measures the weight per unit area of ​​the inspection object B and transmits the weight per unit area of ​​the inspection object B and the coordinates of the measurement position to the functional unit 50. The transmitted weight per unit area and the coordinates of the measurement position of the inspection object B are stored in the storage unit 51. Next, the functional unit 50 transmits the coordinates of the measurement position of the inspection object B to the thickness measuring unit 40. The thickness measuring unit 40 measures the thickness of the inspection object B at the received coordinates of the measurement position of the inspection object B and transmits the received coordinates to the functional unit 50. The transmitted thickness of the inspection object B is stored in the storage unit 51. Next, the derivation unit 52 derivates the porosity of the inspection object B based on the true density of the components of the inspection object B, such as the base material and filler, and the measured values ​​of the weight per unit area and thickness of the inspection object B, which are pre-stored in the storage unit 51. The functional unit 50 transmits the derived porosity of the inspection object B and the measurement position coordinates to the server device 60 via the network NW. The server device 60 determines whether the porosity of the inspection object B is within a specific numerical range to detect defective products.

[0063] According to the porosity derivation device 1 having the above configuration, the porosity of the inspection object B conveyed on the production line can be measured in real time, not by sampling, so that defective products can be surely discovered and the defective rate can be reduced.

[0064] As mentioned above, although the preferred embodiment of the present invention was described, the content of the present invention is not limited to the above-mentioned embodiment, and appropriate changes can be made.

[0065] Reference numerals

[0066] 1: Porosity derivation device

[0067] 30: Unit area weight measurement unit

[0068] 40: Thickness measurement unit

[0069] 51: Storage

[0070] 52: Derivation Department

[0071] B: The subject being examined

[0072] S:Solid electrolyte (electrolyte)

[0073] Nw: non-woven fabric

Claims

1. A porosity derivation method is a method for deducing the porosity of an object under inspection. The object to be inspected is a substrate filled with a filler, and the porosity derivation method includes: a unit area weight measuring step of measuring the unit area weight of a specific portion of the inspection object being transported; a thickness measuring step of measuring the thickness of the specific portion of the inspection object being transported; and, The porosity derivation step is to derive the porosity of the object to be inspected based on the weight per unit area, the thickness, and the true density of the object to be inspected. The unit area weight measuring step is to measure the unit area weight of the substrate and the filler respectively. The porosity derivation step deduces the porosity of the object to be inspected based on the weight per unit area of ​​the base material and the filler, the thickness of the object to be inspected, and the true density of the base material and the filler.

2. The porosity derivation method according to claim 1, wherein: The aforementioned filler is an electrolyte.

3. A porosity derivation device comprising: Transport department, transporting the inspected body; a unit area weight measuring unit for measuring the unit area weight of a specific portion of the inspection object being transported; a thickness measuring unit for measuring the thickness of the specific portion of the inspection object being transported; a storage unit for storing the true density of the object under inspection; and, a derivation unit, which deduces the porosity of the object to be inspected based on the weight per unit area, the thickness, and the true density of the object to be inspected; The aforementioned object to be inspected is a base material filled with a filler, The unit area weight measuring section measures the unit area weights of the substrate and the filler, respectively. The storage unit stores the true density of the filler and the base material. The derivation unit deduces the porosity of the inspection object based on the weight per unit area of ​​the base material and the filler, the thickness of the inspection object, and the true density of the base material and the filler.

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