JP2006172799A - Evaluation method of electrode body, evaluation device using it and electrode body winding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode body winding device simply determining a trouble when a strip-like electrode body is bent and deviated from a winding axis direction. <P>SOLUTION: This electrode body winding device is so structured that two rotatable spindles 1 spaced at a certain distance are formed; the center axes of the two spindles 1 are so arranged as to be parallel with each other; the strip-like electrode body 6 is arranged between the spindles 1 so that certain tension is applied to it; and a gas is jetted to the central part of a flat part of the strip-like electrode body 6 from the normal direction of the flat part of the strip-like electrode body 6, whereby shape abnormality such as curvature of the strip-like electrode body 6 can be determined and discriminated in a short time by observing variation of a flexural shape of the strip-like electrode body 6 from the center axis direction of the spindle 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a strip electrode body evaluation method, an evaluation apparatus based on the evaluation method, and an electrode body winding apparatus.

  In recent years, with the spread of portable and cordless devices such as mobile phones and notebook computers, the demand for batteries for supplying power to these devices has increased. In particular, there is an increasing demand for secondary batteries that are small and light, have high energy density, and can be repeatedly charged and discharged.

  In such a secondary battery, a positive electrode, a negative electrode, and a separator separating the positive electrode and the negative electrode, which are formed and formed in a strip shape, are stacked, and a group of electrodes wound in a spiral shape is inserted into the case, and includes an electrolytic solution. To be configured.

  Conventionally, in the step of transporting the strip electrode body constituting the secondary battery, the battery electrode body for correcting meandering by detecting the edge position of the strip electrode body with the image sensor from the normal direction of the plane portion of the electrode body When this technology is applied to a spiral winding device for an electrode body, a winding device for an electrode body group in which the positive electrode, the negative electrode, and the separator are unlikely to be wound is configured. Yes.

In addition, a meandering prevention device has been invented that can continuously convey a belt-shaped electrode body meandering by a roller even if it is bent from the transport direction (see Patent Document 2).
JP 2000-182610 A Japanese Patent Laid-Open No. 9-017419

  However, when the band-shaped electrode body is bent from the transport direction or the winding direction as described above, the curve of the band-shaped electrode body previously curved from the winding direction is formed before forming the spiral wound electrode body group. It is necessary to measure and measure the degree of anomaly, and to distinguish and distinguish between abnormalities, the operator used a ruler to directly measure the size of the curve and determine the shape abnormality from the size, It has a problem that it takes a long time to discriminate.

  Further, in a device for forming a spiral wound electrode body group having a device for correcting and correcting the meandering of the belt electrode body, when the belt electrode body has an abnormal shape bent from the winding direction, the belt electrode during transportation Even if the meandering of the body can be suppressed, the curved shape of the band-shaped electrode body is maintained, so if a spirally wound electrode body group is formed using such a band-shaped electrode body, winding deviation occurs. There is a problem that the bending of the band-shaped electrode body must be detected and discriminated in-line before the wound electrode body is formed.

  In view of the above problems, an object of the present invention is to use a method for evaluating the shape of a strip electrode body in which the strip electrode body is curved from the winding direction in the electrode body surface direction, and its principle. Thus, an apparatus for evaluating an electrode body and an electrode body winding apparatus including the apparatus for evaluating are provided.

The present invention provides two rotatable support shafts with a certain distance, and is arranged so that the directions of the central axes of the two support shafts are parallel to each other. In a state of being arranged so as to be applied at the same time, a gas is blown at an arbitrary constant pressure from the normal direction of the plane including the central axis of the two spindles toward the center of the plane portion of the strip electrode body, In this evaluation method, the shape of the strip electrode body can be evaluated by measuring the shape change of the strip electrode body from the direction parallel to the central axis direction of the shaft. An electrode body evaluation apparatus and an electrode body winding apparatus are characterized in that the evaluation method is a measurement principle.

  By using the evaluation method of the present invention and the electrode body evaluation device based on the measurement principle, it is not necessary for the operator to directly measure the amount of bending of the strip electrode body from the winding direction with a ruler. Can be easily determined.

  In addition, since it is possible to discriminate the band-shaped electrode body in which the band-shaped electrode body is bent in the winding direction in-line, it is possible to form an electrode body group configured by winding the abnormal electrode body that is bent in the band-shaped electrode body in a spiral shape. It is possible to determine in advance before performing. Furthermore, there is an effect that the consumption of other materials constituting the wound electrode body group can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the evaluation method which can discriminate | determine simply the shape abnormality of the electrode body curved from the winding direction, and the evaluation apparatus of the electrode body which uses it as a measurement principle can be provided. Furthermore, an electrode body winding device capable of discriminating in advance in advance, before forming the wound electrode body group, a bent belt-like electrode body that is a direct cause of winding of the wound electrode body group. Can be provided.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
1 is a perspective view schematically showing an example of an evaluation method and an evaluation apparatus for a strip electrode body according to Embodiment 1 of the present invention, and FIG. 2 is a central axis of support shafts 1a and 1b that support the strip electrode body in FIG. It is the schematic seen from the direction. The two spindles 1a and 1b can rotate, and the interval between the two spindles 1a and 1b is arranged in parallel while maintaining a constant interval. In the strip electrode body 6 cut out with a constant width between the two support shafts 1a and 1b, the direction of the central axis of the support shafts 1a and 1b and the length direction which is the direction of winding the strip electrode body 6 are orthogonal. Arrange so that. Further, the belt-like electrode body 6 applies tension in the direction in which the belt-like electrode body 6 is wound by the tension roller 2, and both ends of the belt-like electrode body 6 in the winding direction are fixed to the fixed shaft 5. At this time, the applied tension is set to 100 gf to 800 gf / mm so that the electrode body is not cut. Further, either one of the tension rollers 2 may be a fixed rotation roller. Furthermore, the nozzle 4 was adjusted and installed so that gas was blown out perpendicularly toward the center part of the flat surface part of the downward direction in the center part between the spindles 1a and 1b. The gas supplied to the nozzle 4 is preferably provided with a buffer tank, a pressure reducing valve, and the like from a tank and a compressor, so that a gas having a constant pressure and a flow rate can be supplied. The gas blown to the electrode body is preferably dried air, nitrogen gas, or an inert gas such as helium, argon, neon, or krypton. Further, the light emitting part 3a and the light receiving part 3b of the sensor are arranged in parallel so as to face each other via the strip electrode body, and a straight line connecting the center of the arranged light emitting part and the center of the light receiving part is orthogonal to the winding direction. Adjust as follows.

When gas is blown from the nozzle 4 to the flat portion of the electrode body, the electrode body is bent or distorted in the normal direction of the plane including the central axes of the support shafts 1a and 1b. At this time, light emitted from the sensor light emitting unit 3a and received by the sensor light receiving unit 4b is blocked by the electrode body, and the area where the light is blocked varies depending on the degree of bending of the electrode body. At this time, the shadow area of the shielded light and the width of the shadow in the normal direction of the plane including the central axis of each of the support shafts 1a and 1b are measured, and from the amount of change, from the winding direction of the electrode body It is determined as a change in shape such as a curve. FIG. 3 shows an enlarged cross-sectional view of the nozzle and sensor portion viewed from the horizontal direction orthogonal to the winding direction of the electrode body. FIG. 4 shows an enlarged cross-sectional view of the nozzle and the sensor portion viewed from the winding direction of the electrode body. If the belt-like electrode body does not curve from the winding direction (length direction) in the electrode body surface direction or the width of the belt-like electrode body does not change, as shown in FIG. However, it bends in a balanced manner in the width direction, and the area where the electrode body cuts off between the sensors is reduced. In addition, if the belt-like electrode body is curved from the winding direction in the electrode body surface direction, the deflection becomes biased in either direction in the width direction, and the area where the electrode body shields the light of the sensor increases or fluctuates. It becomes easy. FIG. 5 is a cross-sectional view seen from the winding direction when the strip-shaped electrode body curved from the winding direction (length direction) in the electrode body surface direction is evaluated. The sensor to be used is preferably a parallel light receiving type line sensor camera or an image sensor for a sensor comprising a light emitting part and a light receiving part.

  Thereby, the shape abnormality which the strip | belt-shaped electrode body curved from the winding direction can be evaluated from the central-axis direction of a spindle.

(Embodiment 2)
FIG. 6 is a perspective view showing an outline of an example of an electrode body winding device including an evaluation method and an evaluation apparatus for a strip electrode body according to Embodiment 2 of the present invention, and FIG. 7 shows a support for supporting the strip electrode body in FIG. It is the schematic seen from the central-axis direction of the axis | shafts 1c and 1d. The second embodiment is an example of an apparatus for forming an electrode body evaluation apparatus and a wound electrode body group shown in FIGS. 6 and 7 and incorporating the first embodiment into a series of apparatuses. This is an example in which the electrode body evaluation method and the evaluation device of Embodiment 1 are incorporated in the middle of a series of devices that form a spirally wound electrode body group from the hoop-shaped electrode body 10. 6 and 7, the belt-like electrode body 6 supplied from the hoop-like electrode body 10 is introduced into a meandering prevention and correction device 8 capable of detecting meandering and correcting meandering, and is introduced into the tension roller 2 via a rotating roller 7. As in the first embodiment, between the sensors 3a and 3b, the direction of the central axis of the support shafts 1a and 1b and the length direction which is the direction of winding the strip electrode body 6 are arranged so as to be perpendicular to each other. A constant tension is applied in the winding direction by the roller.

  In Embodiment 1, it is necessary to cut out a strip electrode body that is firmly fixed by a fixed shaft 5 arranged in the winding direction of the strip electrode body and forms a spiral electrode body group into a certain length and to be installed in the apparatus. However, in Embodiment 2, the strip electrode body can be evaluated in-line from the hoop-shaped electrode body 10 to the wound electrode body group forming apparatus 9 without cutting out the strip-shaped electrode body wound up long. Therefore, it is not necessary to cut out. Further, since the electrode body installed on the support roller can continuously apply a constant tension by the tension roller 2 while continuously moving from the support shaft 1c to the support shaft 1d, the evaluation can be performed continuously and the evaluation process can be performed. I can do it quickly. Thereby, the strip electrode body 6 can be continuously supplied to the wound electrode body group forming apparatus 9. As described above, similarly to the first embodiment, it is possible to evaluate the bending of the strip electrode body from the winding direction, and it is possible to continuously evaluate inline.

  In addition, when the electrode body deviates from the production standard, the wound electrode body group forming apparatus 9 can wind up only the evaluated electrode body and discharge it defectively.

  In addition, a method for manufacturing an electrode body used in the evaluation method of the present invention in Embodiments 1 and 2 and a method for evaluating and verifying a strip electrode body for verifying the effect of the method of the present invention will be described below.

[Production of strip electrode body for evaluation]
The electrode body was prepared by collecting a positive electrode mixture (paint) containing a positive electrode active material made of a lithium-containing composite oxide LixCo1-xO2 (where x satisfies 1.10 ≧ x ≧ 0.98). An electrode body having a thickness of 0.2 mm including a positive electrode mixture layer as a coating layer was prepared by coating aluminum as a metal foil in the form of a metal foil having a thickness of 20 μm and drying. For the formation of the composite material layer, polyvinylidene fluoride (PVdF) was used as a binder. The electrode body evaluated was subjected to the following electrode body evaluation, and the degree of bending was measured to confirm the shape of the electrode body. The produced electrode body produced the normal electrode body without a curve, and the abnormal electrode bodies 1-4 curved from the winding direction of the strip | belt-shaped electrode body.

[Evaluation and verification method of electrode body]
In the verification of the degree of bending, a strip electrode body having a width of 50 mm was cut out at 1 m, and the bending width of the electrode body per 1 m was measured. As shown in FIG. 8, the measuring method is such that the concave portion is directed to the metal straight scale in the width plane direction of the bent electrode body, and the corner of the electrode body cut out at 1 m is in contact with the straight portion of the metal straight scale. The distance (the length of the arrow) between the straight part of the metal straight scale (JIS standard) and the bent electrode body was the farthest distance (the length of the arrow), and the measurement was performed using a metal straight scale. The evaluation results of the normal electrode body and the abnormal electrode body are summarized in Table 1.

  Examples of the present invention will be described below.

Example 1
The electrode body was evaluated using the same evaluation apparatus as in the first embodiment shown in FIGS. The sensor is provided with a sensor light emitting unit 3a and a sensor light receiving unit 3b. The distance between the support shafts 1a and 1b was 60 cm, and a strip electrode body having a width of 50 mm was cut into 100 cm and installed in the apparatus. The tension applied to the electrode body was 500 gf (500 gf / mm). Dry gas having a dew point of −60 ° C. was used as the gas for floating the electrode body. The nozzle 4a uses a linear flow type FL-600B manufactured by Lechier, Germany, and is provided with a compressor and a buffer tank so that the introduction pressure of dry air to the nozzle 4a is 0.1 MPa, and is adjusted by a pressure reducing valve. did.

  A transmissive CCD image sensor (manufactured by Keyence Corporation) was used for the sensor section. The detection accuracy was 0.1 mm. The evaluation was performed by measuring the maximum width in which the emitted light is shielded by the electrode body as shown in FIG. Hereinafter, the maximum width of light shielded by the electrode body is defined as a shielding width. FIG. 3 is a schematic view of the sensor unit at the time of measurement as viewed from the horizontal direction orthogonal to the winding direction, and FIGS. 4 and 5 are enlarged sectional views of the sensor unit at the time of measurement as viewed from the winding direction. Thus, the evaluation method 1 of implementation was implemented.

  The five types of electrode bodies shown in Table 1 were evaluated by the method 1 described above. The evaluation results are shown in Table 2.

  As a result of the evaluation, the normal electrode body 1 shows a minimum value of 0.5 mm, but the bent abnormal electrode bodies 1 to 4 have a shielding width of 1.5 mm or more, and the belt-like electrode body is twisted, The band-shaped electrode body is a band-shaped electrode body that is curved from the winding direction. The band-shaped electrode body having an abnormal shape with a curvature of 1 mm or more has a shielding width of 1.5 mm or more, and a normal electrode body and an abnormal electrode I was able to distinguish and discriminate my body.

(Example 2)
The electrode body mounting conditions were the same as in Example 1. The nozzle 4b uses a flat-flow type FL-600A manufactured by Lechier, Germany, and the dry air introduced into the nozzle 4b is in the compressor and the buffer tank so that the introduction pressure is 0.1 MPa as in the first embodiment. And adjusted with a pressure reducing valve.

  A transmissive CCD image sensor (manufactured by Keyence Corporation) was also used for the sensor section in the same manner as in Example 1. The detection accuracy was 0.1 mm. The evaluation was performed by measuring the maximum width at which the emitted light is shielded by the electrode body, as shown in FIGS. Hereinafter, the maximum width shielded by the electrode body is defined as a shielding width. FIG. 9 is a schematic view of the sensor unit at the time of measurement viewed from the horizontal direction orthogonal to the winding direction, and FIGS. 10 and 11 are enlarged schematic views of the sensor unit at the time of measurement viewed from the winding direction. Thus, the evaluation method 2 of implementation was implemented.

  The five types of electrode bodies shown in Table 1 were evaluated by the evaluation method 2 described above. The evaluation results are shown in Table 3.

  As a result of the evaluation, in the normal electrode body, the shielding width became 0.3 mm and a value slightly larger than the thickness of the strip-shaped electrode body 0.2 mm, but in the abnormal electrode bodies 1 to 4, the shielding width becomes larger than 2 mm, The band-shaped electrode body is greatly twisted and the band-shaped electrode body is curved from the winding direction. The band-shaped electrode body having an abnormal shape whose curvature is 1 mm or more has a shielding width of 2 It was possible to distinguish and distinguish between a normal electrode body and an abnormal electrode body at 0.0 mm or more.

(Example 3)
In the same evaluation apparatus as in the second embodiment, the strip electrode body evaluation method is a series of steps of the apparatus for forming the spiral electrode body group, and the hoop-shaped electrode body 10 shown in FIGS. 6 and 7 is unwound. A series of apparatuses from the apparatus to the formation of the wound electrode body group and the evaluation method of the strip-shaped electrode body that can be continuously evaluated are referred to as an evaluation method 3 for implementation.

As shown in FIG. 6 and FIG. 7, this is a device in which a meandering prevention correcting device 8 is provided from a hoop-like electrode body 10 of a normal electrode body, and the electrode body is guided to the electrode body evaluation method shown in the first embodiment. The tension applied to the electrode body was 500 gf (500 gf / mm ² ).

  Dry gas having a dew point of −60 ° C. was used as the gas for floating the electrode body. The nozzle 4a uses a linear flow type FL-600B manufactured by Lechier, Germany, and is provided with a compressor and a buffer tank so that the introduction pressure of dry air to the nozzle is 0.1 MPa, and is adjusted by a pressure reducing valve. did.

  As in Example 1, a transmissive CCD image sensor (manufactured by Keyence Corporation) was used as the sensor unit. The detection accuracy was 0.1 mm. As shown in FIGS. 4 and 5, the evaluation was performed by measuring the shielding width with the emitted light shielded by the electrode body.

When evaluating the electrode body, the constant tension of 500 gf / mm ² is maintained at a speed of 0.5 m per second in the direction from the support shaft 1c to the support shaft 1d. A strip electrode body was supported.

  A normal electrode body A and abnormal electrode bodies 1A, 2A, 3A, and 4A of a hoop-shaped electrode body prepared by the same method as the normal electrode bodies and abnormal electrode bodies 1 to 5 shown in Table 1 were prepared. While measuring the shielding width with the evaluation device unit including the sensor 3, the electrode body is supplied to the wound electrode body group forming device 9 at a speed of 0.5 m / second, combined with the negative electrode and the separator, and the spiral for the lithium ion battery A group of electrode bodies was formed.

  Thus, after forming the spiral wound electrode body composed of the negative electrode plate and the separator by using the electrode body evaluated by the evaluation method 3 in the evaluation device unit, the spiral wound electrode body is disassembled. And it evaluated also by the evaluation verification method of an electrode body, and verified the evaluation result of the evaluation method 3 of implementation of this invention. For the negative electrode plate, a composite material composed of a graphite material and a styrene butadiene rubber-based binder was applied to a 20 μm-thick Cu current collector to form a 0.2 mm thick negative electrode plate having a width of 50 mm. Was used. A polyethylene porous membrane having a thickness of 20 μm was used as the separator.

  Table 4 shows the evaluation result shielding width (mm) according to the evaluation method 3 and the curvature measured by the evaluation verification method.

  As shown in Table 4, in the abnormal electrode bodies 1A, 2A, 3A, and 4A in which the size of the curve was 1 mm or more by the evaluation verification method, the shielding width was measured at 2.0 mm or more. Even in in-line continuous measurement, a strip electrode body in which the strip electrode body is curved from the winding direction, and an abnormally shaped strip electrode body having a curvature of 1 mm or more has a shielding width of 2.0 mm or more. It was possible to distinguish and discriminate between normal electrode bodies and abnormal electrode bodies.

Example 4
The evaluation method 4 was carried out using the same apparatus as in Example 3 except that only the shape of the nozzle 4a was changed to 4b of FL-600A made by Lechier, a flat plate type used in Example 2. For the evaluation, the normal electrode body A and abnormal electrode bodies 1A, 2A, 3A, and 4A produced in Example 3 were used. Table 5 shows the result of the evaluation result shielding width (mm) according to the evaluation method 4 of the implementation.

As shown in Table 5, the abnormal electrode body 1A in which the size of the curve was 1 mm or more by the evaluation verification method,
In 2A, 3A, and 4A, the shielding width is measured at 2.5 mm or more, and in the continuous measurement by in-line as in Example 3, the band-shaped electrode body is curved from the winding direction and is bent. An abnormally shaped strip-shaped electrode body having a size of 1 mm or more had a shielding width of 2.5 mm or more, and was able to distinguish and discriminate between normal electrode bodies and abnormal electrode bodies.

  Further, by transferring such an abnormality detection signal to the wound electrode body group forming apparatus 9, defective discharge of the electrode body can be facilitated. Further, if the wound electrode body group forming apparatus does not form the wound electrode body group and only the abnormally shaped belt-like electrode body is wound and discharged, members other than the abnormal electrode body constituting the electrode body group Loss consumption can be reduced.

  The strip electrode body evaluation method and evaluation apparatus according to the present invention are suitable for evaluating the shape of the electrode body such as a battery or a capacitor having a spirally wound electrode body group in the width direction, and useful for determining defects. is there.

The perspective view which shows the outline of an example of the evaluation apparatus concerning Embodiment 1 and Example 1 of this invention Schematic view of FIG. 1 viewed from the central axis direction of the support shafts 1a and 1b Schematic view seen from the central axis direction of a part of supporting shafts 1a and 1b of the evaluation apparatus according to Embodiments 1 and 2 and Example 1 of the present invention. Sectional drawing seen from winding direction of a part of evaluation apparatus concerning Embodiment 1, 2 and Example 1 of this invention Sectional drawing seen from winding direction of a part of evaluation apparatus concerning Embodiment 1, 2 and Example 1 of this invention The perspective view which shows the outline of an example of the evaluation apparatus concerning Embodiment 2 and Example 3 of this invention. Schematic view of FIG. 1 viewed from the direction of the central axis of the support shafts 1c and 1d Schematic diagram for the electrode body evaluation verification method Schematic seen from the central axis direction of a part of support shafts 1a and 1b of the evaluation apparatus according to the first embodiment and the second embodiment of the present invention. Sectional drawing seen from winding direction which shows a part of evaluation apparatus concerning Embodiment 1 and Example 2 of this invention Sectional drawing seen from winding direction which shows a part of evaluation apparatus concerning Embodiment 1 and Example 2 of this invention

Explanation of symbols

1a Support shaft (rotating roller)
1b Spindle (Rotating roller)
1c Support shaft (rotating roller)
1d Spindle (Rotating roller)
2 Tension roller 3a Sensor light emitting part 3b Sensor light receiving part 4a Nozzle (linear flow)
4b Nozzle (parallel flow)
DESCRIPTION OF SYMBOLS 5 Fixed axis 6 Strip | belt-shaped electrode body 7 Rotating roller 8 Meander prevention correction apparatus 9 Winding-shaped electrode body group formation apparatus 10 Hoop-shaped electrode body 11 Metal straight scale 12 The width | variety which a strip | belt-shaped electrode body shields emitted light

Claims (3)

  Two rotatable spindles with a certain distance are provided, the central axes of the two spindles are arranged in parallel, and a belt-like electrode body with a constant tension is placed between the spindles. And the bending method of the said strip | belt-shaped electrode body can be evaluated by spraying gas by arbitrary fixed pressure toward the plane part center of the said strip | belt-shaped electrode body, The evaluation method of the electrode body characterized by the above-mentioned.   Two rotatable spindles with a certain distance are provided, the central axes of the two spindles are arranged in parallel, and a belt-like electrode body with a constant tension is placed between the spindles. And the bending of the said strip | belt-shaped electrode body can be evaluated by spraying gas by the arbitrary fixed pressure toward the plane part center of the said strip | belt-shaped electrode body, The evaluation apparatus of the electrode body characterized by the above-mentioned. Two rotatable spindles with a certain distance are provided, the central axes of the two spindles are arranged in parallel, and a belt-like electrode body with a constant tension is placed between the spindles. And the electrode body winding apparatus which comprised the apparatus which evaluates the curvature of the said strip | belt-shaped electrode body by spraying gas by arbitrary fixed pressure toward the plane part center of the said strip | belt-shaped electrode body.