JP2012225848A - Film thickness distribution measurement device and film formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film formation device capable of accurately forming a film on a belt-like base material without deteriorating productivity.SOLUTION: A film formation device comprises a roller 70 that conveys a belt-like base material 10 and a coating section that forms a film in a lengthwise direction of the belt-like base material 10. The device includes: a plurality of displacement sensors 20A and 20B arranged in a straight line along a crosswise direction of the belt-like base material 10; a film thickness distribution measurement section 100 that measures film thickness distribution of a film 12 formed on the belt-like base material 10 by scanning the plurality of displacement sensors 20A and 20B in the crosswise direction of the belt-like base material 10; and a control part that, based on the film thickness distribution of the film 12 measured by the film thickness distribution measurement 100, respectively controls the position, width and thickness of the film 12 formed on the belt-like base material 10 by the coating section.

Description

  The present invention relates to a film thickness distribution measuring device for measuring a film thickness distribution of a coating film formed in the length direction of a strip-shaped substrate, and a coating film forming apparatus for forming a coating film on a strip-shaped substrate.

  In recent years, lithium-ion batteries, nickel-metal hydride batteries, and other secondary batteries have become increasingly important as power sources for vehicles or as power sources for personal computers and portable terminals. In particular, a lithium ion battery that is lightweight and has a high energy density is expected to be preferably used as a high-output power source for mounting on a vehicle.

  In one typical configuration of a lithium ion battery, a battery structure including a wound electrode body having a spiral structure is known. Such a wound electrode body is composed of a strip-shaped electrode (a strip-shaped positive electrode and a strip-shaped negative electrode) and a strip-shaped separator, and is manufactured by stacking and winding each sheet. A strip electrode for a lithium ion battery has a configuration in which a coating film (electrode active material layer) is formed by coating an electrode active material on one or both sides of a metal strip substrate. The strip-shaped electrode is provided with a non-coated portion (a portion where the surface of the strip-shaped base material is exposed without forming a coating film) on a part of the strip-shaped electrode, and an electrode lead (such as a current collecting lead terminal) on the non-coated portion. Is attached.

  As a coating method in which an electrode active material is applied to a strip electrode to form a coating film, for example, there is a method in which a coating film is continuously stripe-coated at a predetermined interval in the length direction of the strip substrate. For example, as shown in FIG. 11, an electrode active material is applied from a die in the length direction of one strip-shaped substrate 1 to form three rows of coating films 3 at predetermined intervals. Slits A to E are respectively formed between the central portion and the coating film 3. And the strip | belt-shaped base material 1 is cut | disconnected by these slits A-E, and six strip | belt-shaped electrodes are manufactured, respectively. At this time, in order to improve the yield, it is important to appropriately provide cutting margins (non-coating portions to which the electrode leads are attached) for forming the slits A to E. It is required to form the coating film 3 with good accuracy such as position, coating film width, coating film thickness, and the like. Patent Documents 1 to 3 are disclosed as conventional techniques for measuring the thickness (height) of this type of coating film.

JP 2009-47665 A International Publication No. 2010/82335 JP 2002-257506 A

  By the way, the inventor measures the position of the coating film formed on the belt-shaped substrate, the width of the coating film, the thickness of the coating film, and the like, and feeds back the coating apparatus that forms the coating film based on the measurement result. By controlling, it is considered to form a coating film with good accuracy, such as the position of the coating film, the width of the coating film, and the thickness of the coating film, on the belt-like substrate. In particular, the coating film formed on the belt-like substrate is considered to be continuously applied while the belt-like substrate is conveyed by a roller. It is preferable that the process can be performed without stopping. As one of this type of coating film forming apparatus, the coating film forming apparatus shown in FIG. 12 has been studied. In the example of FIG. 12, the laser displacement meter 2 is disposed at the end in the width direction of the belt-shaped substrate 1 conveyed by the roller 4, and the laser displacement meter 2 is scanned in the width direction of the belt-shaped substrate 1. The film thickness distribution of the coating film 3 formed on the substrate 1 is measured. And the position of the coating film 3 formed in the strip | belt-shaped base material 1, the width | variety of a coating film, and the thickness of a coating film are each controlled by feeding back the measurement result to a coating part (not shown).

  However, in the apparatus shown in FIG. 12, when measuring the film thickness distribution of the coating film 3 formed on the belt-like substrate 1, the laser displacement meter 2 is set to the full width of the belt-like substrate 1 as shown in FIG. Since it is necessary to scan over a long time, the time required for one scan becomes long. In order to accurately feed back the film thickness measurement result, it is necessary to transport the belt-like substrate 1 in consideration of the scan time. Therefore, the conveyance speed depends on the scan time, and there is a problem that the strip electrode cannot be manufactured efficiently (with high productivity).

  This invention is made | formed in view of this point, The main objective is to provide the coating-film formation apparatus which can form a coating film on a strip | belt-shaped base material accurately, without reducing productivity. It is. Moreover, the other objective is to provide the film thickness distribution measuring apparatus used suitably for such a coating-film formation apparatus.

  The coating-film formation apparatus which concerns on this invention is equipped with the roller which conveys a strip | belt-shaped base material, and the coating part which forms a coating film in the length direction of the said strip-shaped base material. Moreover, the coating film forming apparatus scans the plurality of displacement sensors arranged in a straight line along the width direction of the belt-shaped base material and the plurality of displacement sensors in the width direction of the belt-shaped base material. A film thickness distribution measuring unit that measures the film thickness distribution of the coating film formed on the belt-like substrate. Furthermore, the coating film forming apparatus is based on the film thickness distribution of the coating film measured by the film thickness distribution measuring unit, the position of the coating film formed on the belt-shaped substrate by the coating unit, the width of the coating film, and A control unit for controlling the thickness of each coating film is provided. In a preferred aspect, the displacement sensor is a laser displacement meter.

  According to such a coating film forming apparatus, by measuring a plurality of displacement sensors in the width direction of the belt-like substrate, the film thickness distribution of the coating film formed on the belt-like substrate is measured. It is not necessary to scan over the entire width, and the film thickness distribution of the coating film formed on the belt-like substrate can be measured in a short time. Therefore, the film thickness measurement result can be fed back at a high speed, and even if a coating failure such as misalignment occurs due to a disturbance, it is possible to avoid the occurrence of a large number of defective products. Moreover, according to such a coating film forming apparatus, it is not necessary to scan the displacement sensor over the entire width of the belt-like substrate, and the scanning time of the displacement sensor can be greatly shortened. Therefore, the conveyance speed of the strip-shaped substrate depending on the scan time can be increased as compared with the conventional case, and the coating film can be continuously and efficiently formed on the strip-shaped substrate.

  In a preferred aspect of the coating film forming apparatus disclosed herein, at least two displacement sensors are provided. One displacement sensor is configured to measure the position of one end face in the width direction of the coating film and the thickness in the vicinity thereof, and the other displacement sensor is the other end face opposite to the one end face. And the thickness in the vicinity thereof are configured to be measured. According to this configuration, the width and thickness of the coating film formed on the belt-like substrate can be calculated quickly and easily, and the scan time of the displacement sensor can be further shortened. Here, the thickness in the vicinity of the end face of the coating film refers to the thickness of a flat portion where the film thickness is constant around the end face of the coating film.

  In a preferred aspect of the coating film forming apparatus disclosed herein, at least one of the two displacement sensors is configured to measure the position of the end surface in the width direction of the band-shaped substrate. According to such a configuration, the position of the coating film formed on the belt-like substrate can be calculated at high speed and easily, and the scan time of the displacement sensor can be further shortened.

  In a preferred aspect of the coating film forming apparatus disclosed herein, the plurality of displacement sensors are attached to the same scanning mechanism that movably supports the plurality of displacement sensors. According to this configuration, since the movement of scanning the plurality of displacement sensors in the width direction is synchronized, the film thickness distribution in the width direction can be measured with higher accuracy. Furthermore, since the number of scanning mechanisms can be reduced, the apparatus configuration can be simplified.

  Moreover, this invention provides the film thickness distribution measuring apparatus used suitably for the said coating-film formation apparatus. That is, this film thickness distribution measuring apparatus is a film thickness distribution measuring apparatus that measures the film thickness distribution in the width direction intersecting the length direction of the coating film formed in the length direction of the belt-like substrate. The apparatus includes a plurality of displacement sensors arranged in a straight line along the width direction of the belt-like base material, and the plurality of displacement sensors are scanned in the width direction of the belt-like base material to thereby form the belt-like base material. The film thickness distribution of the coating film formed on is measured. In a preferred aspect, the displacement sensor is a laser displacement meter.

  According to such a film thickness distribution measuring device, a plurality of displacement sensors are scanned in the width direction of the belt-like substrate, thereby measuring the film thickness distribution of the coating film formed on the belt-like substrate. The film thickness distribution of the coated film can be measured in a short time. That is, when measuring the film thickness distribution using one displacement sensor as in the prior art, it is necessary to move the sensor over the entire width of the belt-like substrate, so that one scan time becomes long. According to the invention, by using a plurality of displacement sensors, film thicknesses at different locations can be measured simultaneously, and it is not necessary to move the sensors over the entire width of the belt-like substrate. Therefore, the time required for measurement is extremely short, and the film thickness distribution in the width direction can be measured at high speed.

  The above-mentioned coating film forming apparatus can be preferably used for producing a battery electrode. That is, the present invention provides a coating film forming apparatus that forms a slurry coating film by applying a slurry containing constituent components (for example, an active material, a binder, etc.) of a battery electrode to a strip-shaped substrate (current collector). A battery electrode manufacturing apparatus including the same, and a method for manufacturing a secondary battery (secondary battery electrode) using the coating film forming apparatus are provided. By using the coating film forming apparatus described above, it is possible to efficiently and accurately form a slurry coating film formed on the belt-shaped substrate (current collector). Therefore, it is possible to manufacture a battery electrode with high quality and a battery including the electrode (typically a secondary battery such as a lithium ion battery) with high productivity.

It is a front view which shows typically the film thickness distribution measuring apparatus which concerns on one Embodiment of this invention. It is a figure which shows the scanning locus | trajectory of the displacement sensor which concerns on one Embodiment of this invention. It is a figure for demonstrating the measuring method of the film thickness distribution measuring apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically the coating-film formation apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically the coating part which concerns on one Embodiment of this invention. It is a figure which shows typically the base material travel position adjustment part which concerns on one Embodiment of this invention. It is a block diagram which shows control of the coating-film formation apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the measurement conditions which concern on an Example and a comparative example. It is a figure which shows typically the lithium secondary battery which concerns on one Embodiment of this invention. It is a figure which shows typically the wound electrode body which concerns on one Embodiment of this invention. It is a top view which shows the intermediate body which manufactures a strip | belt-shaped electrode. It is a front view which shows typically the principal part of the conventional coating-film formation apparatus. It is a figure which shows the locus | trajectory of the laser displacement meter used for the conventional coating-film formation apparatus.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. Moreover, in the following drawings, the same code | symbol is attached | subjected and demonstrated to the member and site | part which show | plays the same effect | action. In addition, the following embodiment only illustrates one embodiment of the present invention, and the present invention is not limited to the following embodiment.

  As shown in FIG. 1, the film thickness distribution measuring apparatus 100 according to the present embodiment has a film thickness distribution in the width direction that intersects the length direction of the coating film 12 formed in the length direction of the belt-like substrate 10. It is a device to measure. The film thickness distribution measuring apparatus 100 includes two displacement sensors 20A and 20B arranged on a straight line along the width direction of the belt-like substrate 10. In this embodiment, the two displacement sensors 20 </ b> A and 20 </ b> B are separately disposed on both sides in the width direction of the belt-like substrate 10. In addition, the displacement sensors 20A and 20B are respectively provided above the roller 70 that is transporting the belt-like substrate 10, and are arranged at a certain distance from the surface of the roller 70. The displacement sensors 20 </ b> A and 20 </ b> B are arranged in a straight line along the width direction intersecting with the length direction of the belt-like base material 10 at a location above the roller 70.

  For the displacement sensors 20A and 20B, for example, a commercially available general laser displacement meter (for example, Keyence Corporation) is used. The laser displacement meters 20A and 20B are configured to measure the distance to the target surface by, for example, irradiating the target surface with laser light and receiving reflected light from the target surface. In this embodiment, reference plates 22A and 22B are provided between the displacement sensors 20A and 20B and the roller 70. The displacement sensors 20A and 20B measure the distance to the target surface using the positions of the reference plates 22A and 22B as reference points (origins).

  Further, the displacement sensors 20 </ b> A and 20 </ b> B are attached to a scanning mechanism 30 disposed in parallel with the width direction of the belt-like substrate 10. Then, the scanning mechanism 30 is driven to measure the surface shape in the width direction of the band-shaped substrate 10 while moving in the width direction of the band-shaped substrate 10. Thereby, about distribution of the film thickness of the coating film 12 formed in the strip | belt-shaped base material 10, ie, the position of the coating film 12 with respect to the strip | belt-shaped base material 10, the width | variety of the coating film 12, and the thickness of the coating film 12 It can be measured in 10 width directions. In this embodiment, the scanning mechanism 30 includes a motor 32 and a rail 34. The displacement sensors 20A and 20B are scanned on the rail 34 from the position indicated by the solid line in FIG.

  The arrows 24A and 24B in FIG. 2 represent the trajectories that the displacement sensors 20A and 20B described above have passed over the belt-like substrate 10. The displacement sensors 20A and 20B only move in the width direction of the belt-like base material 10, but since the belt-like base material 10 is conveyed in the direction of the arrow 90 by the roller 70, the trajectories of the displacement sensors 20A and 20B are It becomes zigzag as shown in 2. In the film thickness distribution measurement, one displacement sensor 20A is scanned in the width direction from one end face 16A in the width direction of the belt-like substrate 10 to one end face 14A in the width direction of the coating film 12 in the width direction. The position of one end face 16A in the width direction, the position of one end face 14A of the coating film 12, and the thickness in the vicinity thereof are measured. Further, the other displacement sensor 20B is provided in the vicinity of the other end surface 16B in the width direction of the belt-like substrate 10 and the other end surface in the width direction of the coating film 12 (that is, the other end surface opposite to the one end surface 14A) 14B. Is scanned in the width direction, and the position of the other end face 14B and the thickness in the vicinity thereof are measured. Here, the thickness in the vicinity of the end faces 14A and 14B of the coating film refers to the thickness of a flat portion where the film thickness is constant around the end face of the coating film.

  FIG. 3 shows data of actual measurement values measured by the displacement sensors 20A and 20B. The horizontal axis indicates the position in the width direction of the strip-shaped substrate, and the vertical axis indicates the position in the height direction of the strip-shaped substrate. H0 indicates the surface height of the roller 70 without the belt-like substrate 10.

  Here, the interval in the width direction between the reference plate 22A and the reference plate 22B is L0, the interval in the width direction between the reference plate 22A and one end face 14A of the coating film 12 is L1, and the reference plate 22B and the coating film 12 When the interval in the width direction with the other end surface 14B is L2, the coating width of the coating film 12 formed on the belt-like substrate 10 is “L0-L1-L2”. Further, when the interval in the width direction between the reference plate 22A and one end face 16A of the belt-like substrate 10 is L3, the coating position of the coating film 12 on the belt-like substrate 10 is “L1-L3”. Furthermore, the distance in the height direction between the reference plate 22A and the belt-like substrate 10 is H1, and the vicinity of one end surface 14A of the reference plate 22A and the coating film 12 (a flat portion where the film thickness is constant around the end surface 14A). H2 is the distance in the height direction, and H3 is the distance in the height direction between the reference plate 22B and the vicinity of the other end face 14B of the coating film 12 (a flat portion where the film thickness is constant around the end face 14B). Then, the thickness of the coating film 12 formed on the belt-like substrate 10 is “H1−H2”, and the inclination (thickness difference between both ends) is “H2−H3”. That is, the positions of the reference plates 22A and 22B are set as reference points (origins) in the width direction and the height direction, and the distances L1, L2, L3, H1, H2, H3, etc. from the reference points are determined by the displacement sensors 20A and 20B. By measuring, the position of the coating film formed on the belt-like substrate 10, the width of the coating film, and the thickness (film thickness distribution) of the coating film can be calculated.

  In this embodiment, the film thickness distribution measuring apparatus 100 determines the position of the coating film 12 formed on the belt-shaped substrate 10, the width of the coating film 12, and the coating film 12 from the measurement values measured by the displacement sensors 20 </ b> A and 20 </ b> B. A calculation unit 62 for calculating the thickness (film thickness distribution) is provided. The measurement values measured by the displacement sensors 20A and 20B are sent from the displacement sensors 20A and 20B to the calculation unit 62. The calculation unit 62 performs calculation processing based on the measurement values sent from the displacement sensors 20A and 20B, and the position of the coating film 12 formed on the belt-like substrate 10, the width of the coating film 12, and the thickness of the coating film 12 are calculated. The thickness (film thickness distribution) is calculated. The calculation unit 62 is electrically connected to a storage unit (not shown). The calculation unit 62 executes the above-described calculation process according to the program stored in the storage unit.

  In this way, by disposing the two displacement sensors 20A and 20B along the width direction of the belt-like base material 10 and scanning the two displacement sensors 20A and 20B in the width direction of the belt-like base material 10, The position of the coating film 12 formed on the material 10, the width of the coating film 12, and the thickness (film thickness distribution) of the coating film 12 can be measured.

  According to the film thickness distribution measuring apparatus 100, the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 is measured by scanning the two displacement sensors 20A and 20B in the width direction of the belt-like substrate 10. Therefore, the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 can be measured in a short time. That is, when measuring the film thickness distribution using one displacement sensor as in the prior art, it is necessary to move the sensor over the entire width of the belt-like substrate, so that one scan time becomes long. According to the configuration, by using the two displacement sensors 20A and 20B, the film thickness distribution of the coating film 12 can be independently and simultaneously measured from both sides in the width direction of the belt-like substrate 10, and the sensors 20A and 20B can be measured simultaneously. There is no need to move the entire width of the material 10. Therefore, the time required for measurement is extremely short, and the film thickness distribution in the width direction can be measured at high speed. In this embodiment, the plurality of displacement sensors 20A and 20B are attached to the same scanning mechanism 30 that supports the plurality of displacement sensors so as to be movable. According to this configuration, since the movement of scanning the plurality of displacement sensors 20A and 20B in the width direction is synchronized, the film thickness distribution in the width direction can be accurately measured. Furthermore, since the number of scanning mechanisms 30 can be reduced, the apparatus configuration can be simplified.

  The film thickness distribution measuring apparatus according to the embodiment of the present invention has been described above, but the film thickness distribution measuring apparatus according to the present invention is not limited to the above-described embodiment. For example, although the laser displacement meter using laser light has been exemplified as the displacement sensor, the present invention is not limited to this, and various sensors can be applied as long as the surface shape of the coating film on the belt-shaped substrate can be measured. For example, an optical sensor other than a laser displacement meter may be used. Alternatively, a non-contact sensor such as an ultrasonic sensor can be used. However, as in the above-described embodiment, it is preferable to use a laser displacement meter from the viewpoint of measuring the film thickness distribution accurately and simply.

  Next, a coating film forming apparatus according to an embodiment of the present invention will be described.

  As shown in FIG. 4, the coating film forming apparatus 200 includes a roller 70, a coating unit 40, a base material travel position adjusting unit 50, displacement sensors 20 </ b> A and 20 </ b> B, a film thickness distribution measuring unit 100, and a control. Part 60.

  As shown in FIG. 4, the roller 70 is a device that conveys the belt-like substrate 10. In this embodiment, the belt-like substrate 10 is laid over a plurality of rollers 70 in order, and a certain tension is applied to the belt-like substrate 10. A drive device (not shown) for rolling the roller 70 is attached to some of the rollers 70. The coating film forming apparatus 200 conveys the belt-shaped substrate 10 in the conveyance direction 90 by rolling the roller 70.

  The coating part 40 forms the coating film 12 in the length direction of the belt-like substrate 10 as shown in FIG. In this embodiment, the coating unit 40 includes a die 42 having a discharge hole for discharging a coating liquid obtained by pasting a material for forming the coating film 12, and a coating liquid that supplies the coating liquid to the die 42 at a predetermined pressure. And a supply unit 48. Moreover, in this embodiment, formation of the coating film 12 is performed while conveying the strip-shaped substrate 10. The coating unit 40 includes a die 42 that discharges the coating liquid onto the belt-like substrate 10. A bead 46 in which the coating liquid is accumulated is formed between the die 42 and the belt-like substrate 10. In this coating unit 40, the shape of the bead 46 can be adjusted by adjusting the distance d between the coating liquid discharge hole of the die 42 and the belt-like substrate 10, and the thickness of the coating film 12 and the coating film 12 can be adjusted. The width can be adjusted. Furthermore, by adjusting the inclination of the die 42 with respect to the belt-like substrate 10, it is possible to form the coating film 12 in which the thickness of the coating film 12 (the height of the coating film) is constant in the width direction. In this embodiment, actuators 44 </ b> A and 44 </ b> B that move the coating portion 40 with respect to the belt-like substrate 10 are provided. The actuators 44A and 44B are electrically connected to the control unit 60 and control the position and posture of the die 42 based on commands from there. In this embodiment, the actuators 44A and 44B are motors.

  As shown in FIG. 4, the base material travel position adjusting unit 50 is arranged upstream of the die 42 in the base material transport direction 90 and adjusts the travel position (transport position) in the width direction of the belt-shaped base material 10. It is. In this embodiment, as shown in FIG. 6, the base material travel position adjusting unit 50 has a pair of adjustment reels 52A and 52B in which the belt-like base material 10 is combined on the peripheral surface, and the shafts of the reels 52A and 52B. The travel position in the width direction of the belt-like substrate 10 can be adjusted by changing the angle. In this way, by adjusting the travel position in the width direction of the belt-like substrate 10, it is possible to adjust the travel position in the width direction of the belt-like substrate 10 with respect to the die 42, and thus the formation position of the coating film 12 on the belt-like substrate 10. it can. In this embodiment, an actuator 54 that moves the shaft angle of the pair of reels 52A and 52B is provided. The actuator 54 is electrically connected to the control unit 60, and controls the shaft angle of the pair of reels 52A and 52B based on a command from the actuator 54. In this embodiment, the actuator 54 is a motor.

  The displacement sensors 20 </ b> A and 20 </ b> B are arranged in a line along the width direction of the belt-like substrate 10. The film thickness distribution measuring unit 100 scans the two displacement sensors 20A and 20B in the width direction of the belt-like substrate 10 to thereby obtain the film thickness distribution (position, width and thickness) of the coating film formed on the belt-like substrate 10. ). The sensors 20A and 20B and the film thickness distribution measuring unit 100 have the same configuration as the embodiment of the film thickness distribution measuring apparatus 100 described above. In this embodiment, as shown in FIG. 4, the film thickness distribution measuring unit 100 calculates the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 from the measurement values measured by the displacement sensors 20A and 20B. A calculation unit 62 is provided. The calculation unit 62 of the film thickness distribution measurement unit 100 outputs the calculation result to the control unit 60.

  Based on the film thickness distribution of the coating film 12 measured by the film thickness distribution measuring unit 100, the control unit 60 determines the position of the coating film 12 that the coating unit 40 forms on the belt-shaped substrate 10, the width of the coating film 12, and The thickness of the coating film 12 is controlled. In this embodiment, data relating to the film thickness distribution of the coating film 12 measured by the film thickness distribution measuring unit 100 is sent from the calculation unit 62 of the film thickness distribution measuring unit to the control unit 60. The control unit 60 appropriately operates the actuators 44A and 44B of the coating unit 40 and the actuator 54 of the base material travel position adjusting unit 50 based on the data relating to the film thickness distribution of the coating film 12 to form a belt shape. The position and orientation of the die 42 and the reel 52A so that the coating film 12 formed on the substrate 10 can be accurately formed with respect to the position of the coating film 12, the width of the coating film 12, and the thickness of the coating film 12. , 52B are controlled.

  An example of control by the coating film forming apparatus 200 of this embodiment will be described with reference to the block diagram of FIG. In FIG. 7, the positions surrounded by two-dot chain lines indicate the position of the coating film 12 formed on the belt-like substrate 10, the width of the coating film 12, and the coating value using the measured values of the displacement sensors 20 A and 20 B. This is a calculation unit 62 for obtaining the inclination of the thickness of the film 12. The calculation unit 62 uses the measured values of the displacement sensors 20A and 20B, and the coating film position “L1-L3” of the coating film 12 formed on the belt-like substrate 10 and the coating film width “L0-L1-L2”. ”And the gradient of the coating film thickness“ H2−H3 ”(see FIG. 3).

  Based on the position of the coating film 12 thus obtained, the width of the coating film 12 and the inclination of the thickness of the coating film 12, the position of the coating film 12 applied to the belt-like substrate 10 by the coating unit 40, The width of the coating film 12 and the thickness of the coating film 12 are feedback-controlled. For this purpose, as shown in FIG. 7, the position “L1-L3” of the coating film 12 with respect to the belt-like substrate 10 obtained by the calculation unit 62 and the position (target value) of the coating film set in advance are controlled by the control unit ( For example, it may include a PID controller.) The control unit 60 is configured such that the difference between the position “L1−L3” of the coating film 12 with respect to the belt-like substrate 10 obtained by the calculation unit 62 and the position (target value) of the coating film set in advance becomes zero. The operation amount is calculated based on a predetermined transfer function or the like, and is output to the actuator 54 of the base material travel position adjusting unit 50. And the control part 60 drives the actuator 54 of the base material travel position adjustment part 50 based on the said operation amount, and the position of the coating film 12 with respect to the strip | belt-shaped base material 10 is a target value (predetermined coating position). Thus, the shaft angles of the reels 52A and 52B are controlled.

  Further, as shown in FIG. 7, the width “L0−L1−L2” of the coating film 12 obtained by the calculation unit 62 and a preset coating film width (target value) are input to the control unit 60. The control unit 60 has a predetermined value so that the difference between the width “L0−L1−L2” of the coating film 12 obtained by the calculation unit 62 and the preset width (target value) of the coating film becomes zero. The operation amount is calculated based on the transfer function and the like, and is output to the actuator 44A of the coating unit 40. At this time, a value obtained by subtracting ½ of the thickness gradient “H2−H3” of the coating film 12 obtained by the calculation unit 62 is input to the control unit 60. Further, the control unit 60 is configured such that the difference between the width “L0−L1−L2” of the coating film 12 obtained by the calculation unit 62 and the preset coating film width (target value) is zero. The operation amount is calculated based on a predetermined transfer function or the like and is output to the actuator 44B of the coating unit 40. At that time, a value obtained by adding ½ of the thickness gradient “H2−H3” of the coating film 12 obtained by the calculation unit 62 is input to the control unit 60. And the control part 60 drives each actuator 44A, 44B of the coating part 40 based on each operation amount mentioned above, respectively, and the width | variety and thickness of the coating film 12 formed in the strip | belt-shaped base material 10 are target. The position and posture of the die 42 are controlled so as to be values (predetermined coating width and thickness). The control unit 60 is electrically connected to a storage unit (not shown). The control unit 60 executes the control process described above according to a program stored in the storage unit.

  In this way, the die 42 is formed so that the coating film 12 formed on the belt-like substrate 10 can be accurately formed with respect to the position of the coating film 12, the width of the coating film 12, and the thickness of the coating film 12. The position and posture of the adjusting reels 52 and the axial angles of the adjusting reels 52A and 52B can be controlled.

  As described above, the coating film forming apparatus 200 includes two displacement sensors 20A and 20B arranged in a straight line along the width direction of the belt-shaped substrate 10, and the two displacement sensors 20A and 20B. And a film thickness distribution measuring unit 100 that measures the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 by scanning in the width direction 10. Then, based on the film thickness distribution of the coating film 12 measured by the film thickness distribution measuring unit 100, the coating film 12 formed on the belt-like substrate 10 has the position of the coating film 12, the width of the coating film 12, and the coating film 12. The coating unit 40 is feedback-controlled so that the thickness of the film 12 is accurately formed. Thereby, the position of the coating film 12, the width | variety of the coating film 12, and the thickness of the coating film 12 with respect to the strip | belt-shaped base material 10 can be formed accurately.

  Here, in the conventional coating film forming apparatus, when measuring the film thickness distribution of the coating film formed on the strip-shaped substrate, it is necessary to scan the displacement sensor over the entire width of the strip-shaped substrate, so that Scan time will be longer. That is, there is a problem that the film thickness distribution of the coating film cannot be measured quickly. If the measurement takes time, high-speed feedback control becomes difficult. For example, if a coating failure such as misalignment occurs due to a disturbance, it cannot be corrected quickly and a large number of defective products are generated. Can be.

  On the other hand, according to the coating film forming apparatus 200 of the present embodiment, the plurality of displacement sensors 20A and 20B and the plurality of displacement sensors 20A and 20B arranged in a straight line along the width direction of the belt-shaped substrate 10 are provided. A film thickness distribution measuring unit 100 that measures the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 by scanning in the width direction of the belt-like substrate 10 is provided. The time is extremely short, and the film thickness distribution in the width direction can be acquired at high speed. Therefore, high-speed feedback control is possible. According to such a configuration, even if a coating failure such as misalignment occurs due to a disturbance, it can be corrected quickly and a large number of defective products can be avoided. As a result, waste can be reduced, material costs, material usage efficiency, etc. can be improved very efficiently, and product costs can be reduced. Further, according to the coating film forming apparatus 200, it is not necessary to scan the displacement sensor over the entire width of the belt-like base material, and the scanning time of the displacement sensor can be greatly shortened. Therefore, the conveyance speed of the strip-shaped substrate 10 depending on the scan time can be increased as compared with the conventional case, and the coating film 12 can be continuously formed on the strip-shaped substrate 10 efficiently.

  Next, in order to confirm that the film thickness distribution in the width direction can be measured at high speed by using the coating film forming apparatus 200 according to this embodiment, the following experiment was performed as an example. That is, the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 under the conditions shown in FIG. Here, the film thickness distribution was measured by an averaging process of 8 scans.

  In the comparative example, one laser displacement meter (scanning speed 50 mm / s) was used, and the scan for scanning the range from a1 to a4 in FIG. 8 was repeated 8 times (4 reciprocations). One scan distance was 600 mm, and the time taken for 8 scans was 96 seconds. In this case, assuming that the conveyance speed of the belt-like substrate is 40 m / min, one measurement (8 scans) is performed at intervals of about 64 m. In other words, if a coating failure occurs during operation, there is a possibility that a defective product having a length of at least 64 m may occur before the correction is performed by feedback control.

  In contrast, in the embodiment, two laser displacement meters (scanning speed 50 mm / s) are used, one of which scans the range of a1 to a2 in FIG. 8 and the other of which scans the range of a3 to a4 in FIG. This scan was repeated 8 times (4 reciprocations). The scanning distance for one scan was 120 mm, and the time taken for 8 scans was 19.2 seconds. In this case, when the conveyance speed of the belt-like substrate is 40 m / min, one measurement (8 scans) is performed at intervals of about 12.8 m. In other words, if a coating failure occurs during operation, there is a possibility that a defective product having a length of at least 12.8 m may occur before the correction is performed by feedback control. This value is about 1/5 of the comparative example. From this result, by using two laser displacement meters (scanning speed 50 mm / s), the time for one measurement can be reduced to 20% compared to the case of using one laser displacement meter, and the length of defective products can be reduced. It was confirmed that it can be reduced by nearly 80%.

  As mentioned above, although the coating-film formation apparatus which concerns on one Embodiment of this invention was demonstrated, this invention is not limited to embodiment mentioned above. About the film thickness distribution measurement part of the said coating-film formation apparatus, it is the structure similar to the film thickness distribution measurement apparatus 100 mentioned above, and the same change is possible.

  The film thickness distribution measuring apparatus and the coating film forming apparatus described above are, for example, belt-shaped electrodes (applicable to both positive and negative electrodes) that are constituent elements of a wound electrode body of a battery such as a lithium ion secondary battery. It can be applied to a process of forming a coating film by applying a slurry containing constituent components (for example, an active material, a binder, etc.) of a battery electrode to a base material (current collector). Under the present circumstances, the coating film 12 formed in a strip | belt-shaped base material can be efficiently and highly accurately formed by using the film thickness distribution measuring apparatus and coating film formation apparatus which were mentioned above. Therefore, it is possible to manufacture a battery electrode with high quality and a battery including the electrode (typically a secondary battery such as a lithium ion battery) with high productivity.

  FIG. 2 and FIG. 3 show an embodiment of a lithium secondary battery constructed using a positive electrode strip electrode and a negative electrode strip electrode manufactured using the above-described coating film forming apparatus. This will be described with reference to the schematic diagram.

  As shown in FIG. 9, the lithium secondary battery 1000 according to the present embodiment includes a case 150 made of metal (a resin or a laminate film is also suitable). The case (outer container) 150 includes a flat cuboid case main body 152 having an open upper end, and a lid 154 that closes the opening. The upper surface of the case 150 (that is, the lid 154) is provided with a positive terminal 172 that is electrically connected to the positive electrode 110 of the wound electrode body 180 and a negative terminal 174 that is electrically connected to the negative electrode 120 of the electrode body. Yes. In the case 150, for example, a long sheet-like positive electrode (positive electrode sheet) 110 and a long sheet-like negative electrode (negative electrode sheet) 120 are laminated together with a total of two long sheet-like separators (separator sheets) 130. A flat wound electrode body 180 produced by winding and then crushing the resulting wound body from the side direction and kidnapping is housed.

  As shown in FIG. 10, the wound electrode body 180 is formed by winding a sheet electrode body 182. The sheet-like electrode body 182 has a long (band-like) sheet structure in the stage before assembling the wound electrode body 180. The sheet-like electrode body 182 is formed by laminating a positive electrode sheet 110 and a negative electrode sheet 120 together with a total of two separator sheets 130 in the same manner as a typical wound electrode body.

  The positive electrode sheet 110 is formed by adhering a positive electrode active material layer 114 to both surfaces of a long sheet-like foil-shaped positive electrode current collector 112. However, the positive electrode active material layer 114 is not attached to one side edge along the edge in the width direction of the sheet-like electrode body, and the positive electrode current collector 112 is exposed with a certain width. Similarly to the positive electrode sheet 110, the negative electrode sheet 120 is formed by attaching a negative electrode active material layer 124 to both surfaces of a long sheet-like foil-shaped negative electrode current collector 122. However, the negative electrode active material layer 124 is not attached to one side edge along the edge in the width direction of the sheet-like electrode body, and the negative electrode current collector 122 is exposed with a certain width.

  Examples of the separator sheet 130 used between the positive and negative electrode sheets 110 and 120 include those made of a porous polyolefin resin. Alternatively, a separator having a three-layer structure of polypropylene (PP) / polyethylene (PE) / polypropylene (PP) may be used.

  When constructing the wound electrode body, the positive electrode active material layer non-formation part of the positive electrode sheet 110 and the negative electrode active material layer non-formation part of the negative electrode sheet 120 protrude from both sides of the separator sheet 130 in the width direction. The positive electrode sheet 110 and the negative electrode sheet 120 are overlapped with a slight shift in the width direction. As a result, in the lateral direction with respect to the winding direction of the wound electrode body 180, the electrode active material layer non-formation portions of the positive electrode sheet 110 and the negative electrode sheet 120 are respectively wound core portions (that is, the positive electrode active material layer formation portion of the positive electrode sheet 110). And a portion where the negative electrode active material layer forming portion of the negative electrode sheet 120 and the two separator sheets 130 are wound tightly). A positive electrode lead terminal 176 and a negative electrode lead terminal 178 are attached to the positive electrode side protruding portion (that is, the portion where the positive electrode mixture layer is not formed) 116 and the negative electrode side protruding portion (that is, the portion where the negative electrode mixture layer is not formed) 126, respectively. Are electrically connected to the positive terminal 172 and the negative terminal 174 described above.

Then, the wound electrode body 180 is accommodated in the main body 152 from the upper end opening of the case main body 152 and an electrolytic solution containing an appropriate electrolyte is disposed (injected) in the case main body 152. The electrolyte is lithium salt such as LiPF _6, for example. For example, an appropriate amount (for example, concentration 1M) of a lithium salt such as LiPF ₆ is dissolved in a nonaqueous electrolytic solution such as a mixed solvent of diethyl carbonate and ethylene carbonate (for example, a mass ratio of 1: 1) and used as the electrolytic solution. be able to.

  Thereafter, the opening is sealed by welding with the lid body 154, and the assembly of the lithium secondary battery 1000 according to the present embodiment is completed. The sealing process of the case 150 and the process of placing (injecting) the electrolyte may be the same as those used in the production of a conventional lithium secondary battery, and do not characterize the present invention. In this way, the construction of the lithium secondary battery 1000 according to the present embodiment is completed.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, the number of displacement sensors arranged along the width direction of the strip-shaped substrate 10 is not limited to two as described above, and may be two or more (for example, 2 to 5). As the number of sensors increases, the film thickness distribution of the coating film 12 formed on the belt-like substrate 10 can be measured with higher accuracy. However, as in the above-described embodiment, an aspect using two displacement sensors is preferable from the viewpoint of simplifying the apparatus configuration.

  Moreover, although the example mentioned above demonstrated the case where the coating-film formation apparatus of this invention was used as a coating-film formation apparatus for electrode manufacture, it is not limited to this. The film thickness distribution measuring apparatus and the coating film forming apparatus according to the present invention are not limited to the process of forming a coating film of an electrode active material on a strip electrode, which is a constituent element of a wound electrode body of a battery such as a lithium secondary battery. It can be widely applied to applications for forming a coating film on a belt-like substrate.

DESCRIPTION OF SYMBOLS 10 Band-shaped base material 12 Coating film 14A, 14B End surface 16A of coating film End surface 20A, 20B of belt-shaped base material Displacement sensors 22A, 22B Reference plate 30 Scanning mechanism 32 Motor 34 Rail 40 Coating part 42 Die 44A, 44B Actuator 46 Bead 48 Coating liquid supply unit 50 Base material travel position adjustment unit 52A Adjustment reel 54 Actuator 60 Control unit 62 Calculation unit 70 Roller 90 Conveying direction 100 Film thickness distribution measuring device 110 Positive electrode sheet 112 Positive electrode current collector 114 Positive electrode active material layer 120 Negative electrode sheet 122 negative electrode current collector 124 negative electrode active material layer 130 separator sheet 150 case 152 case body 154 lid body 172 positive electrode terminal 174 negative electrode terminal 176 positive electrode lead terminal 178 negative electrode lead terminal 180 wound electrode body 200 coating film forming apparatus 1000 lithium secondary battery

Claims (12)

A roller for conveying the belt-shaped substrate;
A coating film forming apparatus provided with a coating part that forms a coating film in the length direction of the belt-shaped substrate,
A plurality of displacement sensors arranged in a straight line along the width direction of the belt-shaped substrate;
A film thickness distribution measuring unit that measures the film thickness distribution of the coating film formed on the band-shaped substrate by scanning the plurality of displacement sensors in the width direction of the band-shaped substrate;
Based on the film thickness distribution of the coating film measured by the film thickness distribution measuring section, the position of the coating film, the width of the coating film, and the thickness of the coating film that are formed on the belt-shaped substrate by the coating section are controlled. The coating-film formation apparatus provided with the control part to perform. At least two displacement sensors are provided, and one displacement sensor is configured to measure the position of one end face in the width direction of the coating film and the thickness in the vicinity thereof,
The coating film forming apparatus according to claim 1, wherein the other displacement sensor is configured to measure a position of the other end surface opposite to the one end surface and a thickness in the vicinity thereof.   The coating film forming apparatus according to claim 2, wherein at least one of the two displacement sensors is configured to measure a position of an end face in the width direction of the belt-like base material.   The coating film forming apparatus according to claim 1, wherein the plurality of displacement sensors are attached to the same scanning mechanism that movably supports the plurality of displacement sensors.   The coating film forming apparatus according to claim 1, wherein the displacement sensor is a laser displacement meter. A film thickness distribution measuring device for measuring a film thickness distribution in the width direction intersecting the length direction of the coating film formed in the length direction of the belt-shaped substrate,
A plurality of displacement sensors arranged in a straight line along the width direction of the band-shaped substrate, and formed on the band-shaped substrate by scanning the plurality of displacement sensors in the width direction of the band-shaped substrate. A film thickness distribution measuring device for measuring the film thickness distribution of a coating film. At least two displacement sensors are provided, and one displacement sensor is configured to measure the position of one end face in the width direction of the coating film and the thickness in the vicinity thereof,
7. The film thickness distribution measuring apparatus according to claim 6, wherein the other displacement sensor is configured to measure a position of the other end face opposite to the one end face and a thickness in the vicinity thereof.   The film thickness distribution measuring apparatus according to claim 7, wherein at least one of the two displacement sensors is configured to measure a position of an end face in the width direction of the belt-like base material.   9. The film thickness distribution measuring apparatus according to claim 6, wherein the plurality of displacement sensors are attached to the same scanning mechanism that movably supports the plurality of displacement sensors.   The film thickness distribution measuring apparatus according to any one of claims 6 to 9, wherein the displacement sensor is a laser displacement meter. A method for producing an electrode for a secondary battery, comprising:
Applying an electrode active material layer forming composition prepared in the form of a slurry to the surface of a long strip-shaped electrode current collector; and
Drying the coating film made of the composition formed on the surface of the current collector;
Including
The electrode active material layer forming composition is applied using the coating film forming apparatus according to any one of claims 1 to 5, wherein the electrode for a secondary battery is characterized in that Production method. The manufacturing method of a secondary battery using the electrode for secondary batteries manufactured by the manufacturing method of Claim 11.

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