阅读说明：本技术 用于确定复合片材重量的设备 (Apparatus for determining the weight of a composite sheet ) 是由 托比亚斯·内贝尔 塞巴斯蒂安·蒂克西尔 迈克尔·孔·耀·休斯 格特詹·霍夫曼 保罗·蒙特 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种用于对复合片材(180)进行重量测量的测量设备(100),该测量设备包括其上具有第二材料的片材材料(180a),该第二材料作为涂层(180b)和/或作为其中的嵌入粒子(180c)。该设备包括x射线传感器(110)和红外(IR)传感器(120),该x射线传感器用于从照射复合片材的x射线提供x射线信号,该红外(IR)传感器用于从照射复合片材的IR提供IR信号。计算装置(150)被联接以接收x射线信号和IR信号,该计算装置包括处理器(151),该处理器具有相关联存储器(151)以用于实施算法,其中该算法使用x射线信号和IR信号来计算选自片材材料的重量、第二材料的重量和复合片材的总重量的多个重量。(A measuring device (100) for gravimetric measurement of composite sheets (180) comprises a sheet material (180a) having a second material thereon as a coating (180b) and/or as embedded particles (180c) therein. The apparatus includes an x-ray sensor (110) for providing an x-ray signal from x-rays illuminating the composite sheet and an Infrared (IR) sensor (120) for providing an IR signal from IR illuminating the composite sheet. A computing device (150) is coupled to receive the x-ray signal and the IR signal, the computing device including a processor (151) having associated memory (151) for implementing an algorithm, wherein the algorithm uses the x-ray signal and the IR signal to calculate a plurality of weights selected from the group consisting of a weight of the sheet material, a weight of the second material, and a total weight of the composite sheet.)

1. A measuring device (100) for measuring the weight of a composite sheet (180) comprising a sheet material (180a) having a second material thereon as a coating (180b) or as embedded particles (180c) therein, the measuring device comprising:

an X-ray sensor (110) comprising an X-ray source (110a) and an X-ray detector (110b) for providing an X-ray signal from X-rays illuminating the composite sheet;

an Infrared (IR) sensor (120) comprising at least one IR source (120a), at least one IR filter (114) and at least one IR detector (120b) for providing an IR signal from IR illuminating the composite sheet, and

a computing device (150) coupled to receive the x-ray signal and the IR signal, the computing device comprising a processor (151) having associated memory (152) for implementing an algorithm,

wherein the algorithm uses the x-ray signal and the IR signal to calculate a plurality of weights selected from the weight of the sheet material, the weight of the second material, and the total weight of the composite sheet.

2. The measurement device of claim 1, further comprising a scanner head (160), wherein both the x-ray sensor and the IR sensor are movable by the scanner head for scanning the composite sheet to generate a two-dimensional (2D) measurement profile.

3. The measurement device of claim 1, wherein the IR sensor comprises a transmission sensor.

4. The measurement device of claim 1, wherein the algorithm utilizes a calibration table relating an output of the measurement device to the weight of the sheet material, the weight of the second material, and the total weight of the composite sheet, and utilizes the calibration table for determining the plurality of weights.

5. The measurement apparatus of claim 1, wherein the sheet material has an aperture, wherein the algorithm further utilizes a reference baseline level to provide correction for light scattering effects of the aperture.

6. A method of analysing a composite sheet (180) comprising a sheet material (180a) having a second material as a coating thereon (when 180b) or as embedded particles (180c) therein, the method comprising:

determining an X-ray signal from X-rays illuminating the composite sheet using an X-ray sensor (110);

determining an Infrared (IR) signal from IR illuminating the composite sheet using an IR sensor (120), an

Determining a plurality of weights selected from the weight of the sheet material, the weight of the second material, and the total weight of the composite sheet from the x-ray signal and the IR signal.

7. The method of claim 6, wherein the second material comprises a ceramic material, and wherein the sheet material comprises a polymeric material.

8. The method of claim 7, wherein the ceramic material comprises Al₂O₃、SiO₂Or ZrO₂And wherein said polymeric materialThe material comprises Polyethylene (PE) or polypropylene (PP), or a combination of said PE and said PP.

9. The method of claim 6, wherein the sheet material has holes, and wherein the determining comprises utilizing an algorithm that also utilizes a reference baseline level to provide a correction for light scattering effects of the holes.

10. The method of claim 6, wherein the method is performed during production of the composite sheet having the plurality of weights for controlling at least one parameter of a coating process used to form the second material.

Technical Field

The disclosed embodiments relate to weight measurement for composite sheets that include a sheet material having a coating thereon or a material embedded therein.

Background

Ceramic coated Polyethylene (PE) or polypropylene (PP) separator films are important components for the realization of lithium ion batteries, which typically comprise a polymer sheet material as separator film. The separator membrane provides an ion permeable barrier between the cathode and the anode of the lithium ion battery. These separator membranes are porous and, if uncoated, typically begin to degrade at temperatures of about 120 ℃, causing the lithium ion battery to short circuit and thus fail. Ceramic coatings applied to separator films (e.g., Al) are known₂O₃) Helping to increase the separator's temperature stability up to about 200 ℃, but resulting in reduced separator membrane permeability and increased weight.

For measuring the coating weight of a separator film coating, Infrared (IR) based weight sensors (IR sensors) are known. The IR sensor analyzes specific spectral regions in the near and mid infrared that are sensitive to the separator film and/or coating. Ceramics absorb in the IR at relatively long wavelengths, which requires sensitive and cooled detectors. This constitutes a challenge when online measurements with high signal-to-noise ratio (SNR) are required. Nuclear gauges (e.g. betameters) are also known for determining the coating weight and the weight of the separator film, but the measurement system is based on a subtractive method requiring at least two scanner heads. Furthermore, nuclear gauges are often not required due to radiation safety concerns.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description, including the figures provided. This summary is not intended to limit the scope of the claimed subject matter.

The disclosed embodiments recognize that industries such as the lithium ion battery industry require cost effective non-nuclear solutions for determining multiple weights of a composite sheet having a second material as a coating material on and/or embedded particles in a general polymer sheet material, including the weight of the sheet material, the weight of the second material, and the total weight of the composite sheet. Furthermore, it is recognized that a single scanner head solution that avoids the use of a nuclear gauge is desirable to avoid the known safety issues.

Aspects disclosed herein include a measuring device for measuring the weight of a composite sheet comprising a sheet material having a second material thereon as a coating and/or having embedded particles therein. The apparatus includes an x-ray sensor for providing an x-ray signal by irradiating the composite sheet and an IR sensor for providing an IR signal by irradiating the composite sheet. A computing device is coupled to receive the x-ray signal and the IR signal, the computing device including a processor having associated memory for implementing an algorithm, wherein the algorithm uses the x-ray signal and the IR signal to calculate a plurality of weights selected from the group consisting of a weight of the sheet material, a weight of the second material, and a total weight of the composite sheet. The measuring device typically includes a movable scanner head for scanning a corresponding sensor, such as shown in FIG. 1 described below.

Drawings

Fig. 1 is a depiction of an exemplary measurement device including an x-ray sensor and an IR sensor configured as transmission sensors for determining at least two weights of a composite sheet selected from the group consisting of a weight of a sheet material, a weight of a second material, and a total weight of the composite sheet, according to an exemplary embodiment.

Fig. 2 is a depiction of an exemplary measurement device including an X-ray sensor and an IR sensor configured as reflective sensors for determining a weight of a composite sheet, the weight including at least two weights of the composite sheet selected from the group consisting of a weight of a sheet material, a weight of a second material, and a total weight of the composite sheet, according to another exemplary embodiment.

FIG. 3 is an x-ray sensitivity graph illustrating the principle of operation of the disclosed aspects of the present invention depicting the expected response of an x-ray sensor when measuring different composite sheet samples.

Fig. 4 shows a plot of an exemplary IR absorption spectrum versus wavelength λ (in arbitrary units, e.g., in microns (μm)) for one particular composite sheet sample.

Detailed Description

The disclosed embodiments are described with reference to the drawings, wherein like reference numerals are used to refer to similar or equivalent elements throughout the several views. The drawings are not to scale and are provided merely to illustrate certain disclosed aspects. Several disclosed aspects are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the disclosed embodiments.

The disclosed measurement apparatus includes two different sensors, including an x-ray sensor and an IR sensor, which together are used to measure properties of a composite sheet (such as a separator sheet for a lithium ion battery) after a second material is applied to the sheet material. Fig. 1 is a depiction of an exemplary measurement device 100 for weight measurement of a composite sheet 180 according to an exemplary embodiment. The composite sheet 180 includes a sheet material 180a having a second material thereon as a coating 180b and/or having embedded particles 180c therein.

The measurement apparatus 100 includes an x-ray sensor 110 and an IR sensor 120 for determining two or more of a weight of the sheet material 180a, a weight of the second material, and a total weight of the composite sheet 180. Both the x-ray sensor 110 and the IR sensor 120 are shown in FIG. 1 as transmission sensors, and thus both have an upper half and a lower half, where in the upper half, the x-ray source 110a is shown as T-ray source 110a_XAnd IR emitter 120a is shown as T_XAnd in the lower half, x-ray detector 110b is shown as R_XAnd IR detector 120b is shown as R_X. The IR sensor 120 may alternatively be a reflection-based sensor as shown in fig. 2, but the x-ray sensor 110 is typically a transmission sensor.

IR sensor 120 may utilize commercially available IR sensors for measurements up to about 12 μm wavelength to examine specific spectral region characteristics of a composite sheet that may include a ceramic coated plastic spacer film by applying a spectral filter, shown as bandpass filter 114 shown in fig. 1, to the IR signal. One spectral region (3.4 μm for PE) covers the absorption peak which is usually very pronounced. One or more spectral filters may cover the reference region near the absorption peak (see fig. 4 described below).

A background-free absorption signal can be calculated from the IR spectrum using reference measurements. One embodiment does not use a reference measurement, but relies on the IR signal without background correction. The signal generated by the IR sensor 120 is typically primarily sensitive to the sheet material 180a, while the signal from the x-ray sensor 110 is typically primarily sensitive to the weight of the second material. When the sheet material absorption peak is selected (as shown in FIG. 4, i.e., a 3.4 μm PE absorption peak), IR is primarily sensitive to the sheet material 180 a. In contrast to the sheet material 180a (such as a PE or PP polymer substrate), X-rays are primarily sensitive to the second material because the second material comprises a high-Z material (e.g., a material containing Al, Si, or Zr, such as Al)₂O₃、SiO₂Or ZrO₂)。

The measurement device 100 includes a scanner head 160 that includes a top scanner head 160a and a bottom scanner head 160b for mounting components of the x-ray sensor 110 and the IR sensor 120. Position control of the scanner head 160 is well known. The scanner head 160 may scan over a portion of the width or the entire width of the composite sheet 180, including during production of the composite sheet.

Inside the scanner heads 160a, 160b, the x-ray sensor 110 and the IR sensor 120 are mounted along lines that may be parallel to the Machine Direction (MD) or in the Cross Direction (CD). The scanner heads 160a, 160b may scan across the composite sheet 180 to display a representation of the composite sheet 180, sometimes referred to as a "web," moving between the scanner heads 160a, 160 b. The signals from the respective detectors 110b, 120b are typically processed by electronics (not shown) including filters, analog-to-digital converters (ADCs) and amplifiers, and then passed to a computing device 150 including a processor 151 having associated memory 152. Also not shown are electronics between processor 151 and x-ray source 110a and IR source 120a, which typically include at least a digital-to-analog converter (DAC).

The processor 151 takes the sensor measurements received from the x-ray sensors 110 in the IR sensor 120 and calculates a second material weight (in this example, a coating weight) using an algorithm or digital logic. It should be noted that some of this processing may be performed within the respective sensors 110, 120 themselves. There may be other inputs to the processor 151 such as the head position or longitudinal position of the scanner heads 160a, 160 b. The output from the processor 151 may be simply the weight of the second material in the form of the coating 180b and/or embedded particles 180c in the sheet material 180a as a function of position, or some control signal for controlling a coater that applies a coating of the second material on the sheet material 180a (such as a separator sheet). Processor 151 may also output a signal to control the second material weight applied to sheet material 180 a.

x-ray sensor 110 (e.g., configured to operate at 3keV to 6keV, such as 4keV to 5 keV) provides a measurement of the total weight of composite sheet 180. However, due to the higher density and higher atomic number of the second material as compared to sheet material 180a, when sheet material 180a includes a plastic film, x-ray measurements are typically about 10 times more sensitive to the weight of the second material than to the weight of sheet material 180 a.

By measuring the respective inputs from the detector 110b of the x-ray sensor 110 and the detector 120b of the IR sensor 120, two of the following three possible outputs may be determined: the weight of the sheet material 180a, the weight of the second material, and the total weight of the composite sheet 180. The third weight may be calculated from the first two weights. The overall measurements may be calibrated by performing a dual predictor (x-ray and IR) partial least squares regression (or similar statistical methods such as Principal Component Analysis (PCA)) on a set of composite sheet samples with known sheet material weight and coating weight spectral parameters.

Fig. 2 is a depiction of an exemplary measurement device 200 including an x-ray sensor 110 and an IR sensor 120' configured as reflective sensors for determining a weight of composite sheet 180, the weight including at least two weights of composite sheet 180 selected from the group consisting of a weight of sheet material 180a, a weight of a second material, and a total weight of composite sheet 180, according to an exemplary embodiment.

Thus, the disclosed embodiments include an IR sensor portion in either a transmissive or reflective configuration, both performed in a direct line of sight measurement or in an offset setting to observe scattered light while using at least one IR spectral region. The IR sensor 120 (in fig. 1) or the IR sensor 120' (in fig. 2) may cover spectral regions up to long-wave IR (lwir), such as up to 14 μm. The IR indicia may be used to determine different grades of the composite sheet 180 sample, such as grouping into two different grades. These groups differ in certain IR spectral characteristics that can be used to select the appropriate calibration. In the case of PE as the sheet material 180a, the spectral region can be, for example, -2.4 μm, -3.4 μm, -6.8 μm, -13.8 μm, or generally any combination thereof.

The disclosed aspects provide benefits including x-ray measurements that provide a total weight measurement of the composite sheet 180, such as a coated separator film, which, as described above, is typically about 10 times more sensitive to coating weight than it is to sheet material 180a (e.g., film) weight changes. In an embodiment where a coating weight measurement accuracy of about 10% is sufficient, and the sheet material (e.g., separator film) thickness is known a priori (e.g., by caliper measurement), only x-ray measurements may generally be sufficient.

The combination of x-ray and IR sensor measurements disclosed herein enables the weight of sheet material 180a to be determined, either on one measuring device 100 shown in FIG. 1 or on device 200 shown in FIG. 2, along with the weight of a second material that is a coating and/or embedded in sheet material 180 a. The disclosed solution is cost effective when mounted on the scanner head 160, as compared to the known 2-scanner and nuclear (referred to as beta gauge) solution.

The disclosed embodiments may generally be applied to determine the weight of any coating or embedded material of any sheet material 180a, such as a ceramic coating in or on a polymer sheet. Both the second material (as a coating and/or as an embedded material) and the sheet material 180a may be porous. Sheet material 180a may include multiple layers of different polymers, such as a stack of polymer layers including PE/PP/PE, PP/PE/PP, PE/PP/PE.

Examples

The disclosed embodiments are further illustrated by the following specific examples, which should not be construed as in any way limiting the scope or content of the disclosure.

FIG. 3 illustrates an x-ray sensitivity graph illustrating the principle of operation of the disclosed aspects of the present invention. Fig. 3 depicts the expected response of the x-ray sensor 110 when measuring different composite sheet 180 samples. These composite sheet samples consisted of a layer of PE or PP sheet material 180a, which typically had a coating 180b comprising alumina thereon. A data set of sheet material 180a having a constant weight is visually supported by the dashed lines shown. Along the dashed line, only the weight of the coating 180b changes, while the weight of the sheet material 180a remains unchanged. The solid line shown connects the data for the composite sheet 180 sample without the coating so that only the sheet material weight is changed.

The two different slopes of these lines indicate that the x-ray sensor measurements are more sensitive to changes in the weight of the coating 180b than to changes in the weight of the sheet material 180 a. This is due to the coating 180b having a higher Z (atomic number; such as aluminum containing an atomic number of 13, for example in the case of alumina) component than the carbon in the polymer of the sheet material 180a, thereby causing a stronger x-ray absorption than the sheet material 180 a. Fig. 3 also shows that the x-ray measurements are primarily sensitive to changes in the weight of the coating 180 b. On the other hand, the IR measurement is tailored to the particular absorption characteristics of the sheet material 180a by selecting an appropriate IR filter (see band pass filter 114 shown in FIGS. 1 and 2 above), which will therefore be primarily sensitive to weight changes of the sheet material 180 a. In this way, two fairly independent measurements (from the x-ray sensor and from the IR sensor) may be used to determine two unknown weights of composite sheet 180 (including coating 180b on sheet material 180a), such as the weight of sheet material 180a and the weight of coating 180 b.

Fig. 4 shows a plot of an exemplary IR absorption spectrum versus wavelength λ (in arbitrary units, e.g., in μm) for one composite sheet sample. The optical IR filter added to the IR sensor extracts the signal generated by the sheet material 180 a. Optical filters applied to the left (lower wavelength) and right (higher wavelength) sides of the sheet material 180a features may be used to provide a reference baseline level that may improve signal quality. Providing a reference-baseline level is optional. The use of one or more reference signals as a means of correcting the measurement signal from variations due to electronic component drift, lamp power and sheet scatter power variations is well known in the art. The hole size in the sheet material is typically of the same order of magnitude as the wavelength of the IR light from the IR sensor, so the IR light is typically significantly scattered, except for being absorbed by the sheet material 180 a. Variations in pore size distribution can affect light scattering capabilities.

While various disclosed embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Many changes may be made to the subject matter disclosed herein in accordance with this disclosure without departing from the spirit or scope of the disclosure. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.