Ultrasonic processing equipment

Abstract

The simple and inexpensive configuration allows for the formation of electrode sheets of the desired thickness with minimal load. [Solution] The distance between the processing tools 34 of the horns 2 of the first and second devices, which are positioned above and below the electrode sheet W, is maintained at a value equal to the sum of the thickness of the hardened electrode sheet W and the amplitude of the ultrasonic vibration. With the electrode sheet W transferred between the two processing tools 34 and held between them, ultrasonic vibrations are applied via the two processing tools 34 in a vertical direction perpendicular to the upper and lower surfaces of the electrode sheet W. As a result, the electrode sheet W can be hardened to the desired thickness with a smaller load compared to the conventional method of pressing and hardening with press rolls, and a large press machine becomes unnecessary.

Description

Technical Field

[0001] The present invention relates to an ultrasonic processing device for consolidating an electrode sheet in which active material layers of a secondary battery are provided on both the upper and lower surfaces of a metal foil.

Background Art

[0002] As shown in FIG. 14, a lithium-ion secondary battery has a structure in which a positive electrode (cathode) 700 and a negative electrode (anode) 800 are alternately and repeatedly laminated while being separated by a separator 900. The positive electrode 700 is formed by forming an active material layer in which an active material for a positive electrode is consolidated with a binder on a current collector and shaping it into a sheet. Similarly, the negative electrode 800 is formed by forming an active material layer in which an active material for a negative electrode is consolidated with a binder on a current collector and shaping it into a sheet (see paragraph 0003 and FIG. 7 of Patent Document 1).

[0003] As a method of shaping this type of positive electrode 700 and negative electrode 800 into sheets, conventionally, it is common to press and compress them as described in Patent Document 2. That is, as a conventional shaping method, for example, an active material layer for a positive electrode consolidated with a binder is formed on both sides of an aluminum foil, and the positive electrode 700 is shaped into a sheet by pressing from both sides with a pair of pressing rolls. Similarly, for example, an active material layer for a negative electrode consolidated with a binder is formed on both sides of a copper foil, and the negative electrode 800 is shaped into a sheet by pressing from both sides with a pair of pressing rolls (see Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the case of conventional electrode sheet formation methods such as those described in Patent Document 2, since the active material layer is pressed using a press roll, it is necessary to press with a large linear pressure (load per unit length in the width direction of the sheet) to compress the active material layer and obtain an electrode sheet of a predetermined thickness. This requires a large and expensive press machine, which is a costly problem.

[0006] This invention has been made in view of the above-mentioned problems, and aims to enable the formation of electrode sheets of a desired thickness with a small load using a simple and inexpensive configuration. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the ultrasonic processing apparatus according to the present invention is an ultrasonic processing apparatus for solidifying an electrode sheet having an active material layer for a secondary battery provided on both the upper and lower surfaces of a metal foil, and is characterized in that it comprises an upper horn and a lower horn arranged opposite to each other above and below the electrode sheet, a transfer means for transferring the electrode sheet between the two horns, and an ultrasonic vibration means for applying ultrasonic vibrations in a vertical direction perpendicular to the upper and lower surfaces of the electrode sheet via the two horns while the electrode sheet transferred between the two horns by the transfer means is sandwiched between the two horns, and the distance between the two horns is set to a value obtained by adding the amplitude of the ultrasonic vibration to the thickness of the electrode sheet after solidification.

[0008] With this configuration, the distance between the upper and lower horns positioned above and below the electrode sheet is set to a value obtained by adding the amplitude of the ultrasonic vibration to the thickness of the electrode sheet after it has been solidified. The electrode sheet is then transported between the two horns by a transport means and held between them. Ultrasonic vibrations are then applied through the two horns in a longitudinal direction perpendicular to the upper and lower surfaces of the electrode sheet. Compared to conventional methods of solidifying by pressing with press rolls, the electrode sheet can be solidified to the desired thickness with a smaller load. This eliminates the need for large and expensive press machines, and allows for the formation of an electrode sheet of the desired thickness with a simple and inexpensive configuration.

[0009] Furthermore, it is preferable to further include a load detection means for detecting the load when the electrode sheet is clamped by both horns, and a load means for moving each of the horns vertically and variably adjusting the distance between the two horns so that the load detected by the load detection means becomes a preset load.

[0010] With this configuration, the load detection means adjusts the distance between the upper and lower horns using the load means so that the load detected by the load detection means becomes a preset load. This prevents cracking of the active material by applying ultrasonic vibrations under excessive load to solidify the electrode sheet, and the load detection means and load means can solidify the electrode sheet with an appropriate load.

[0011] Furthermore, it is preferable that multiple sets of horns, each consisting of two horns positioned opposite each other above and below the electrode sheet, be arranged in a line in the width direction of the electrode sheet, perpendicular to the transport direction by the transport means. In this case, if the length of the horns in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet perpendicular to the transport direction, the electrode sheet can be reinforced across its width by multiple sets of horns arranged in the width direction of the electrode sheet (perpendicular to the transport direction).

[0012] In this case, it is preferable that the multiple sets of horns are arranged so that the ends of each set of horns overlap when viewed from the direction of transport. By arranging the multiple sets of horns in this way, so that the ends of each set of horns overlap when viewed from the direction of transport, it is possible to prevent areas from forming in the width direction of the electrode sheet from solidifying, and the electrode sheet can be solidified evenly by the multiple sets of horns.

[0013] Furthermore, the ultrasonic processing apparatus according to the present invention is an ultrasonic processing apparatus for solidifying an electrode sheet having layers of active material for a secondary battery provided on both the upper and lower surfaces of a metal foil, and is characterized in that it comprises a support arranged below the electrode sheet to support the electrode sheet, a horn arranged above the electrode sheet opposite the support, a transfer means for transferring the electrode sheet between the support and the horn, and an ultrasonic vibration means for applying ultrasonic vibration through the horn while the electrode sheet transferred between the support and the horn by the transfer means is sandwiched between the support and the horn, and the distance between the support and the horn is set to a value obtained by adding the amplitude of the ultrasonic vibration to the thickness of the electrode sheet after solidification.

[0014] With this configuration, the distance between the horns and support positioned above and below the electrode sheet is set to a value obtained by adding the amplitude of the ultrasonic vibration to the thickness of the electrode sheet after it has been solidified. The transport means then holds the transported electrode sheet between the horns and the support, and applies longitudinal ultrasonic vibrations perpendicular to the upper and lower surfaces of the electrode sheet through the horns. Compared to conventional methods of solidifying by compression with press rolls, the electrode sheet can be solidified to the desired thickness with a smaller load, eliminating the need for a large and expensive press machine, and enabling the formation of an electrode sheet of the desired thickness with a simple and inexpensive configuration.

[0015] Furthermore, it is preferable to further include load detection means for detecting the load when the electrode sheet is clamped by the support and the horn, and load means for moving the horn vertically relative to the support and variably adjusting the distance between the horn and the support so that the load detected by the load detection means becomes a preset load.

[0016] With this configuration, the load detection means adjusts the distance between the horn and the support so that the load detected by the load detection means becomes a preset load. This prevents cracking of the active material by applying ultrasonic vibrations under excessive load to solidify the electrode sheet, and the load detection means and load means can solidify the electrode sheet with an appropriate load.

[0017] Furthermore, the length of the support in the direction perpendicular to the transport direction by the transport means may be longer than the width of the electrode sheet in the direction perpendicular to the transport direction, and the horns may be arranged in a row in the width direction of the electrode sheet. In this case, if the length of the horn in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet in the direction perpendicular to the transport direction, the electrode sheet can be reinforced by multiple horns across its width by arranging multiple horns in the width direction of the electrode sheet (in the direction perpendicular to the transport direction).

[0018] Furthermore, the multiple horns may be arranged so that their ends overlap when viewed from the transport direction. By arranging the multiple horns in this way, so that their ends overlap when viewed from the transport direction, it is possible to prevent areas from becoming unsolidified in the width direction of the electrode sheet, and the electrode sheet can be solidified evenly by the multiple horns.

[0019] Furthermore, it is preferable to further provide a preheating means for preheating the active material layer of the electrode sheet. In this case, preheating the active material layer with the preheating means softens the active material layer, making it denser, and allowing ultrasonic vibration energy to be applied.

[0020] Furthermore, it is desirable that the electrode sheets are positive electrode sheets and negative electrode sheets for lithium-ion batteries. In this case, high-quality positive electrode sheets and negative electrode sheets can be provided as electrode sheets for lithium-ion batteries. [Effects of the Invention]

[0021] According to the present invention, compared with the case of forming an electrode sheet by pressing with a conventional pair of press rolls, an electrode sheet with a desired thickness can be formed with a small load by a simple and inexpensive configuration.

Brief Description of the Drawings

[0022] [Figure 1] It is a side view of the first embodiment of the ultrasonic processing apparatus according to the present invention. [Figure 2] It is a perspective view showing the operating state of the apparatus of FIG. 1. [Figure 3] It is an operation explanatory diagram of the apparatus of FIG. 1. [Figure 4] It is an operation explanatory diagram of the apparatus of FIG. 1. [Figure 5] It is a diagram showing the comparison results of the load and the occurrence status of cracks when the electrode sheet is hardened by ultrasonic vibration by the apparatus of FIG. 1 and when it is hardened by a conventional press. [Figure 6] It is a perspective view showing the operating state of the second embodiment of the ultrasonic processing apparatus according to the present invention. [Figure 7] It is a plan view showing the operating state of the third embodiment of the ultrasonic processing apparatus according to the present invention. [Figure 8] It is a side view of the fourth embodiment of the ultrasonic processing apparatus according to the present invention. [Figure 9] It is an operation explanatory diagram of the apparatus of FIG. 8. [Figure 10] It is an operation explanatory diagram of the apparatus of FIG. 8. [Figure 11] It is an operation explanatory diagram of the apparatus of FIG. 8. [Figure 12] It is a perspective view showing the operating state of the fifth embodiment of the ultrasonic processing apparatus according to the present invention. [Figure 13] It is a perspective view showing the operating state of the sixth embodiment of the ultrasonic processing apparatus according to the present invention. [Figure 14] It is a perspective view showing an outline of the configuration of a conventional lithium ion battery. [[ID=I]]

Modes for Carrying Out the Invention

[0023] (First Embodiment) A first embodiment of the ultrasonic processing apparatus according to the present invention will be described with reference to Figures 1 to 5.

[0024] <Device configuration> Figure 1 shows an ultrasonic processing apparatus 1, which comprises a first device 2A that operates an upper horn located above the electrode sheet (described later) and a second device 2B that operates a lower horn located below the electrode sheet. The first device 2A and the second device 2B have the same configuration. The configuration of the first device 2A will be described in detail below, and the configuration of the second device 2B will be described in detail using the same reference numerals as the first device 2A, without further explanation.

[0025] As shown in Figure 1, the first apparatus 2A comprises a head unit 3, a control device 4, and a loading means 5. The head unit 3 includes a transducer 31 that applies ultrasonic vibration in the Z-axis direction (vertical direction) in Figure 1, which is the pressurizing direction, a horn 32 connected to one end of the transducer 31, and a support means 35 that supports the transducer 31 and the horn 32 so as to be movable in the vertical direction, which is the vibration direction. The transducer 31 causes the horn 32 to vibrate ultrasonically, thereby applying ultrasonic vibration to the workpiece and processing the workpiece. Here, the horn 32 is composed of a horn body 33 and a processing tool 34 having a rectangular parallelepiped shape with one long side end tapered, attached to the horn body on the opposite side from the transducer 31. The workpiece is a positive electrode sheet and a negative electrode sheet used as electrode sheets for a lithium-ion battery, which will be described later, and the active material layer is solidified by ultrasonic vibration.

[0026] The control device 4 is a microcomputer equipped with a CPU and memory, and is responsible for controlling the vibration of the transducers 31 of the first device 2A and the second device 2B, as well as controlling the load of the load means 5. Specifically, the load means 5 applies a load to the electrode sheet in the vertical direction (Z-axis direction) through load control, while the ultrasonic vibrations from the transducer 31 apply ultrasonic vibration energy in the vertical direction, which is a longitudinal vibration, to the horn body 33 and the processing tool 34, thereby solidifying the electrode sheet.

[0027] Here, the positive electrode sheet is formed by creating a sheet on both sides of an aluminum foil by forming a positive electrode active material layer made of a metal oxide that can reversibly dope and dedope lithium ions onto both sides. Preferred metal oxides include, for example, lithium cobaltate, lithium nickelate, lithium manganeseate, and lithium iron phosphate. The negative electrode sheet is formed by creating a sheet on both sides of a copper foil by forming a negative electrode active material layer made of low-crystalline carbon (amorphous carbon) such as easily graphitizable carbon, poorly graphitizable carbon, and pyrolytic carbon, graphite (natural graphite, artificial graphite), alloy materials such as tin and silicon, silicon oxide, tin oxide, lithium titanate, and other oxides.

[0028] Furthermore, as shown in Figure 1, the head unit 3 is equipped with a support means 35 that supports the transducer 31 and the horn 32 so as to be movable in the same Z-axis direction (vertical direction) as the vibration direction, and the transducer 31 of the first device 2A and the second device 2B respectively vibrates the horn 32 ultrasonically, thereby solidifying the active material layer of the electrode sheet. Here, the transducer 31 and the horn 32 (horn body 33 and processing tool 34) correspond to the "ultrasonic vibration means" in the present invention.

[0029] Specifically, the horn 32 vibrates ultrasonically in the vertical direction (Z-axis direction / vertical direction in Figure 1), which is the direction of its central axis, in resonance with the ultrasonic vibrations generated by the transducer 31 controlled by the control device 4. The horn body 33 of the horn 32 is formed to a length of one wavelength of the resonant frequency such that, for example, the position approximately in the center of the horn body 33 in the Z-axis direction and the positions at both its upper and lower ends are the points of maximum amplitude. The processing tool 34 is attached to the point of maximum amplitude at the lower end of the horn body 33. In addition, two positions 1 / 4 wavelength away from each maximum amplitude point in the vertical direction (Z-axis direction) correspond to the first and second minimum amplitude points of the horn body 33, respectively, and the horn body 33 is supported by the support means 35 at these first and second minimum amplitude points.

[0030] Here, the horn body 33 and processing tool 34 constituting the horn 32 may be formed from various metal materials commonly used to form resonators, such as titanium, titanium alloy, iron, stainless steel, aluminum, aluminum alloys such as duralumin, high-carbon steel that can be heat-treated, or iron with cemented carbide (tungsten carbide) attached to the tip. Furthermore, the horn 32 should be configured such that its resonant frequency is approximately 15 kHz to approximately 60 kHz and its vibration amplitude (amplitude of expansion and contraction in the Z-axis direction in Figure 1) is approximately 1 μm to approximately 300 μm. In this embodiment, it is most desirable to configure it to have a vibration amplitude of approximately 20 μm.

[0031] As shown in Figure 1, the support means 35 comprises a movable support 54 (described later) and two clamping means 36, and the clamping means 36 grip and support the gripped portion of the horn body 33. The two clamping means 36 are provided at two locations on the movable support 54 so that they can grip (clamp) the two gripped portions formed on the horn body 33, and each clamping means 36 comprises a first member and a second member that clamp the gripped portion of the horn body 33.

[0032] Specifically, the first and second members of each of the two clamping means 36 are provided with recesses that have a shape capable of engaging with the cross-sectional shape of the gripped portion of the horn body 33. The first and second members of the clamping means 36, supported by the movable support 54, are fitted into the recesses so as to grip the gripped portion of the horn body 33 with the recesses of the first and second members, and the first and second members are fixed with bolts, thereby gripping the gripped portion of the horn body 33 by both clamping means 36 and supporting the horn 32.

[0033] Furthermore, the configuration of the support means 35 for supporting the horn 32 is not limited to two clamping means 36 fixed by bolts while gripping the gripping portion formed on the horn body 33, as described above. It may be any configuration that can support the gripping portion of the horn body 33, such as an electrically controllable mechanical clamping mechanism or a clamping mechanism that can be attached with a single touch.

[0034] Furthermore, the position of the gripping portion formed on the horn body 33 is not limited to the minimum amplitude point; the gripping portion can be formed at any position on the horn body 33. Moreover, the configuration of the gripping portion is not limited to a configuration in which a concave groove is formed along the circumferential direction on the outer surface of the horn body 33; for example, a configuration in which a convex flange is formed along the circumferential direction on the outer surface of the horn body 33 may be formed, or any other shape in which the gripping portion can be gripped by the support means 35. In addition, the gripping portion may be supported by the support means 35 via an elastic member such as an O-ring or a diaphragm.

[0035] As shown in Figure 1, the loading means 5 moves the horn 32 vertically by moving the support means 35 that supports the horn 32 in the vertical direction (Z-axis direction). The loading means 5 comprises a drive motor 51, a ball screw 52 that rotates vertically (Z-axis direction) by the drive motor 51, a U-shaped frame 53 in side view that rotatably supports the upper and lower ends of the ball screw 52, ​​and a rectangular parallelepiped movable support 54 in which the ball screw 52 is screwed into a vertically oriented female thread formed in the center, with two clamping means 36 of the support means 35 connected to the X-side.

[0036] As shown in Figure 1, the frame 53 comprises a long flat plate portion 53a in the vertical direction (Z-axis direction), horizontal extensions 53b integrally provided at the upper and lower ends of the flat plate portion 53a to rotatably support the upper and lower ends of the ball screw 52, ​​and a vertical guide rail 53c mounted on the -X side of the flat plate portion 53a between the upper and lower extensions 53b so as to follow the flat plate portion 53a. Here, a drive motor 51 is placed on the upper surface of the upper extension 53b, and the guide rail 53c is fitted into a vertical guide groove (Z-axis direction) formed on the +X side surface of the movable support 54. The control device 4 controls the rotation of the drive motor 51, causing the ball screw 52 to rotate, and the movable support 54 moves vertically (Z-axis direction) along the guide rail 53c.

[0037] At this time, as the movable support 54 moves upward or downward in accordance with the rotation direction of the ball screw 52, ​​the two clamping means 36 connected to the movable support 54 move up and down, causing the horn body 33 to move closer to or further away from the electrode sheet. Then, the downward movement of the clamping means 36 due to the downward movement of the movable support 54 causes the electrode sheet to be clamped between the processing tools 34 that are attached to the horn bodies 33 of the first and second devices 2A and 2B and arranged facing each other. At this time, the control device 4 controls the drive motors 51 of the first and second devices 2A and 2B so that the positions of both processing tools 34 are kept constant, so that the distance between the two processing tools 34 of the first and second devices 2A and 2B is maintained at a predetermined distance. Here, the distance between the two processing tools 34 of the first and second devices 2A and 2B corresponds to the "distance between the two horns" in this invention.

[0038] Incidentally, the head section 3 of the first and second devices 2A and 2B are equipped with load sensors (not shown) which serve as load detection means, such as load cells. The load applied to the electrode sheet sandwiched between the processing tools 34 by each load means 5 is detected by the load sensors, and the load control of the drive motors 51 of the first and second devices 2A and 2B is performed so that a load greater than a preset load is not applied to the electrode sheet. Furthermore, the movable support bodies 54 of the first and second devices 2A and 2B are equipped with linear encoders 6 (see Figure 1), which detect the height of the head section 3 of the first and second devices 2A and 2B in the vertical direction (Z-axis direction). The control device 4 adjusts the height of the head section 3 by controlling the drive motors 51 of the first and second devices 2A and 2B based on the detection signal from the linear encoder 6, thereby adjusting the height position of the processing tools 34 of the first and second devices 2A and 2B relative to the electrode sheet.

[0039] As shown in Figure 2, the length Lt of the processing tool 34 of the horns 32 of the first and second devices 2A and 2B in the direction perpendicular to the transport direction of the electrode sheet W (arrow direction in Figure 2) is greater than the width Ls of the electrode sheet W in the same perpendicular direction, so that both processing tools 34 can contact the entire width of the electrode sheet W.

[0040] Figure 3 shows a cross-section of an electrode sheet W, which is made of a metal foil Mt with active material layers Am on both sides. When the electrode sheet W is for the positive electrode (cathode), the positive electrode active material layers described above are provided on both sides of the aluminum foil. When the electrode sheet W is for the positive electrode (anode), the negative electrode active material layers described above are provided on both sides of the copper foil. The electrode sheet W is wound onto a supply roll Ra shown in Figure 2, and the electrode sheet W is unwound from this supply roll Ra and wound onto a winding roll Rb, thereby transporting the electrode sheet W in the direction of the arrow in Figure 2. At this time, for example, the electrode sheet W is transported by rotating the winding roll Rb at a predetermined speed by a motor. Here, the supply roll Ra and the winding roll Rb correspond to the "transport means" in this invention.

[0041] <Operation> As shown in Figure 4, if the distance between the two processing tools 34 of the first apparatus 2A and the second apparatus 2B before vibration is kept constant at, for example, 100 μm, and the vibration amplitude of both horns 32 of the first and second apparatuses 2A and 2B is 20 μm, then when ultrasonic vibration energy is applied to both processing tools 34 with the electrode sheet W sandwiched in the 100 μm gap between the processing tools 34 in the horns 32 of the first and second apparatuses 2A and 2B, the electrode sheet W is compressed and hardened by the ultrasonic vibration of each processing tool 34 by twice the vibration amplitude (20 μm), which is 40 μm, and the thickness of the electrode sheet W is compressed from 100 μm before sandwiching to 60 μm.

[0042] At this time, the ultrasonic vibration energy of the processing tools 34 of the first and second devices 2A and 2B causes the active material in the active material layer Am of the electrode sheet W to vibrate, eliminating the gaps between the particles. Furthermore, the ultrasonic vibration generates frictional heat that raises the temperature of the active material particles, causing them to soften and making the gaps between the particles of the active material denser. Combined with the load applied when the electrode sheet passes between the two processing tools 34, the electrode sheet W is pressed and solidified with a small load. Therefore, without applying a large load like that required when solidifying with a conventional press machine, the gaps between the particles of the active material in the active material layer Am are almost eliminated by the ultrasonic vibration energy, allowing the electrode sheet W to be solidified with a load smaller than that of conventional presses. Furthermore, the loading means 5 can variably adjust the spacing between the processing tools 34 of the first and second devices 2A and 2B so that the load detected by the load sensor, which is a load detection means, becomes a preset load. This prevents cracking of the active material by solidifying the electrode sheet W by applying ultrasonic vibration when an excessive load is applied.

[0043] Figure 5 shows the results of comparing the state solidified by conventional press load and the state solidified by ultrasonic vibration according to this embodiment. As shown in Figure 5, it was found that the load required to obtain the same thickness as the electrode sheet W after solidification is smaller when solidified by ultrasonic vibration than when solidified by conventional press load. Furthermore, in the case of conventional press load, the load is greater than that of the processing tool 34 in this embodiment, so the press rolls are in contact with the electrode sheet W over a larger area due to the larger load. In contrast, in this embodiment, the load of the processing tool 34 is smaller, so the contact area of ​​the processing tool 34 with the electrode sheet W is smaller, and it was found that the occurrence of cracks in the active material layer Am of the electrode sheet W can be significantly suppressed.

[0044] Therefore, according to the first embodiment, the distance between the processing tools 34 of the horns 32 of the first device 2A and the second device 2B, which are positioned above and below the electrode sheet W, is maintained at a value equal to the sum of the thickness of the solidified electrode sheet W and the amplitude of the ultrasonic vibration. By applying longitudinal ultrasonic vibrations perpendicular to the upper and lower surfaces of the electrode sheet W through the processing tools 34 while the electrode sheet W is held between the two processing tools 34, the electrode sheet W can be solidified to the desired thickness with a smaller load compared to the conventional method of solidifying by pressing with a press roll. As a result, a large and expensive press machine is not required, and an electrode sheet of the desired thickness can be formed with a simple and inexpensive configuration. The reason why a small load is required when solidifying with ultrasonic vibration is presumed to be that, as described above, the gaps between the granular particles of the active material of the electrode sheet W are almost completely eliminated by the ultrasonic vibration energy during solidification.

[0045] Furthermore, the load means 5 can variably adjust the distance between the processing tools 34 of the first and second devices 2A and 2B so that the load detected by the load sensor, which is a load detection means, becomes a preset load. This prevents ultrasonic vibration from being applied to the electrode sheet W while excessive load is applied between the two processing tools 34 in response to load fluctuations, thereby suppressing cracking in the active material of the electrode sheet W after it has hardened.

[0046] (Second Embodiment) A second embodiment of the ultrasonic processing apparatus according to the present invention will be described with reference to Figure 6. The following description will focus on the differences from the first embodiment. Figures 1 to 4 will also be referenced in the following description, and in Figure 6, the same reference numerals as in Figure 2 indicate the same or equivalent components.

[0047] In the second embodiment, the length of the processing tools 34 constituting the horns 32 of the first and second devices 2A and 2B in the direction perpendicular to the transport direction (arrow direction in Figure 2) of the electrode sheet W is different from that of the first embodiment. That is, when the length of the processing tools 34 constituting the horns 32 in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet W perpendicular to the transport direction, as shown in Figure 6, three sets of horns 32 are provided in the first and second devices 2A and 2B, and the processing tools 34 constituting each set of horns 32 are arranged in the width direction of the electrode sheet W (direction perpendicular to the transport direction), so that the total length of the three sets of processing tools 34 is longer than the width of the electrode sheet W.

[0048] Therefore, according to the second embodiment, in addition to obtaining the same effects as the first embodiment, even when the length of the processing tool 34 in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet W perpendicular to the transport direction, the electrode sheet W can be solidified at once by the three sets of processing tools 34 across the width direction by arranging the three sets of processing tools 34 side by side in the width direction of the electrode sheet W.

[0049] Furthermore, if the length of the processing tool 34 constituting the horn 32 in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet W perpendicular to the transport direction, it is of course possible to arrange two or more sets of processing tools 34 in the width direction in addition to the three sets described above.

[0050] (Third embodiment) As a third embodiment of the ultrasonic processing apparatus according to the present invention, as in the second embodiment described above, the processing tools 34 of the three sets of horns 32 in the first and second apparatuses 2A and 2B may be arranged as shown in Figure 7, such that the ends of the processing tools 34 of each set overlap when viewed from the direction of transport of the electrode sheet W (direction of the arrow in Figure 7).

[0051] As in the third embodiment, by arranging each set of processing tools 34 so that their ends overlap when viewed from the transport direction, it is possible to reliably prevent the occurrence of areas where the electrode sheet W cannot be compacted in the width direction, and to compact the electrode sheet W uniformly by each set of processing tools 34. Needless to say, the same effects as in the first embodiment can be obtained in the third embodiment.

[0052] (Fourth Embodiment) A fourth embodiment of the ultrasonic processing apparatus according to the present invention will be described with reference to Figures 8 to 11. The following description will focus on the differences from the first embodiment. Figures 1 to 4 will also be referenced in the following description, and in Figures 8 to 11, the same reference numerals as in Figures 1 to 4 indicate the same or equivalent components.

[0053] In the fourth embodiment, the difference from the first embodiment is that instead of using two devices with the same configuration as the first and second devices 2A and 2B, as shown in Figure 8, only the first device 2A is used as the ultrasonic processing device 11, the support 7 is placed opposite the processing tool 34, and as shown in Figures 9 and 10, the electrode sheet W is sandwiched between the processing tool 34 and the support 7, ultrasonic vibration is applied, and the electrode sheet W is pressed and solidified. Hereafter, the first device 2A may be simply referred to as "device 2A". The length of the processing tool 34 and the support 7 in the direction perpendicular to the transport direction of the electrode sheet W (arrow direction in Figure 9) is greater than the width of the electrode sheet W in the same perpendicular direction.

[0054] In this case, as shown in Figure 11, if the distance between the processing tool 34 and the support 7 of the first device 2A constituting the ultrasonic processing apparatus 11 is maintained at, for example, 100 μm, and the vibration amplitude of the horn 32 of the first device 2 is 20 μm, then when ultrasonic vibration energy is applied to the processing tool 34 while the electrode sheet W is sandwiched in the 100 μm gap between the processing tool 34 and the support 7 of the first device 2, the electrode sheet W is compressed and hardened by the ultrasonic vibration of the processing tool 34 by a thickness of 20 μm, which is the vibration amplitude. As a result, the thickness of the electrode sheet W is compressed from 100 μm before sandwiching to 80 μm.

[0055] In this case, as shown in Figure 10, at the portion where the electrode sheet W is clamped between the processing tool 34 and the support 7, the support 7 also vibrates in response to the ultrasonic vibration energy of the processing tool 34. Therefore, although the electrode sheet W is slightly compressed in the thickness direction by the support 7 at the contact portion, the amount of the electrode sheet W is not compressed by the amplitude of the ultrasonic vibration as in the first embodiment. Nevertheless, it is possible to press and solidify the electrode sheet W to a degree comparable to that of the first embodiment.

[0056] Therefore, according to the fourth embodiment, the same effects as the first embodiment can be obtained. Furthermore, unlike the first embodiment, there is no need to use two first and second devices 2A and 2B with the same configuration, and the electrode sheet W can be solidified with a single device 2A, making it possible to solidify the electrode sheet W with a simpler and less expensive device.

[0057] (Fifth embodiment) A fifth embodiment of the ultrasonic processing apparatus according to the present invention will be described with reference to Figure 12. The following description will focus on the differences from the fourth embodiment. In the following description, Figures 1 to 4 relating to the first embodiment will also be referenced, and in Figure 12, the same reference numerals as in Figure 2 indicate the same or equivalent components.

[0058] In the fifth embodiment, as shown in Figure 12, the length of the processing tool 34 constituting the horn 32 of the first apparatus 2A in the direction perpendicular to the transport direction (arrow direction in Figure 12) of the electrode sheet W is different from that of the fourth embodiment. That is, when the length of the processing tool 34 constituting the horn 32 in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet W perpendicular to the transport direction, as shown in Figure 12, three sets of horns 32 are provided in the first apparatus 2A, and the processing tools 34 constituting each set of horns 32 are arranged in the width direction of the electrode sheet W (direction perpendicular to the transport direction), so that the total length of the three sets of processing tools 34 is longer than the width of the electrode sheet W.

[0059] Therefore, according to the fifth embodiment, in addition to obtaining the same effects as the fourth embodiment, even when the length of the processing tool 34 in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet W perpendicular to the transport direction, by arranging the three sets of processing tools 34 side by side in the width direction of the electrode sheet W, it becomes possible to solidify the electrode sheet W across its width at once with the three sets of processing tools 34.

[0060] Furthermore, if the length of the processing tool 34 constituting the horn 32 in the direction perpendicular to the transport direction is smaller than the width of the electrode sheet W perpendicular to the transport direction, it is of course possible to arrange two or more sets of processing tools 34 in the width direction in addition to the three sets described above.

[0061] (Sixth Embodiment) As a sixth embodiment of the ultrasonic processing apparatus according to the present invention, as in the fifth embodiment described above, the processing tools 34 of the three sets of horns 32 of the first apparatus 2A may be arranged so that, as shown in Figure 13, the ends of the processing tools 34 of each set overlap when viewed from the direction of transport of the electrode sheet W (direction of the arrow in Figure 13).

[0062] As in the sixth embodiment, by arranging each set of processing tools 34 so that their ends overlap when viewed from the transport direction, it is possible to reliably prevent the occurrence of areas where the electrode sheet W cannot be compacted in the width direction, and to compact the electrode sheet W uniformly by each set of processing tools 34. Furthermore, it goes without saying that the same effects as in the first embodiment can be obtained in the sixth embodiment.

[0063] It should be noted that the present invention is not limited to the embodiments described above, and various modifications other than those described above can be made without departing from the spirit of the invention.

[0064] In each of the embodiments described above, a preheating means for preheating the active material layer Am of the electrode sheet W may be provided. In this case, a heater as a preheating means may be built into one of the horns 32 or all of the horns 32 or the support 7 and controlled by the control device 4. The preheating temperature is preferably set in a temperature range of, for example, 40°C to 200°C.

[0065] Furthermore, although the electrode sheet W was described in the above-described embodiment as a positive electrode sheet and a negative electrode sheet used in a lithium-ion battery, it may also be an electrode sheet for a secondary battery other than the electrode sheet W.

[0066] Furthermore, although the above-described embodiment explained that the horn 32 is composed of the horn body 33 and the processing tool 34, the horn 32 is not limited to the configuration described in the above-described embodiment. Moreover, the processing tool 34 is not limited to the shape described above.

[0067] Furthermore, the present invention can be applied to an ultrasonic processing apparatus for solidifying an electrode sheet, which is made of a metal foil with active material layers for a secondary battery on both the upper and lower surfaces. [Explanation of Symbols]

[0068] 1,11…Ultrasonic processing equipment 2...First device 3...Second device 5...Loading means 7...Support 31 … Transducer (ultrasonic vibration means) 32... Horn (ultrasonic vibration means) 33... Horn body 34… Processing Tools Ra... Supply roll (transfer means) Rb... Winding roll (transfer means) W... Electrode sheet Am...active material layer Mt...metal foil

Claims

1. In an ultrasonic processing apparatus for solidifying an electrode sheet, which is made of a metal foil with active material layers for a secondary battery on both the upper and lower surfaces, An upper horn and a lower horn are arranged facing each other above and below the electrode sheet, A transfer means for transferring the electrode sheet between the two horns, With the electrode sheet, which has been transferred between the two horns by the transfer means, being held between the two horns, an ultrasonic vibration means applies vertical ultrasonic vibrations perpendicular to the upper and lower surfaces of the electrode sheet via the two horns. Equipped with, An ultrasonic processing apparatus characterized in that the distance between the two horns is set to a value obtained by adding the amplitude of the ultrasonic vibration to the thickness of the electrode sheet after it has been solidified.

2. A load detection means for detecting the load when the electrode sheet is clamped by the two horns, A load means that moves each of the two horns vertically and adjusts the distance between the two horns so that the load detected by the load detection means becomes a preset load. The ultrasonic processing apparatus according to claim 1, further comprising the features described above.

3. The horns arranged opposite each other above and below the electrode sheet are considered as one set, The ultrasonic processing apparatus according to claim 1 or 2, characterized in that a plurality of sets of horns are arranged in a line in the width direction of the electrode sheet, which is perpendicular to the transport direction by the transport means.

4. The ultrasonic processing apparatus according to claim 3, characterized in that the plurality of sets of horns are arranged such that the ends of each set of horns overlap when viewed from the transport direction.

5. In an ultrasonic processing apparatus for solidifying an electrode sheet, which is made of a metal foil with active material layers for a secondary battery on both the upper and lower surfaces, A support positioned below the electrode sheet and supporting the electrode sheet, A horn is positioned above the electrode sheet, facing the support, A transfer means for transferring the electrode sheet between the support and the horn, An ultrasonic vibration means applies ultrasonic vibrations through the horn while the electrode sheet, which has been transferred between the support and the horn by the transfer means, is sandwiched between the support and the horn. Equipped with, An ultrasonic processing apparatus characterized in that the distance between the support and the horn is set to a value obtained by adding the amplitude of ultrasonic vibration to the thickness of the electrode sheet after it has been solidified.

6. A load detection means for detecting the load when the electrode sheet is clamped by the support and the horn, A load means that moves the horn vertically relative to the support and variably adjusts the distance between the horn and the support so that the load detected by the load detection means becomes a preset load. The ultrasonic processing apparatus according to claim 5, further comprising:

7. The length of the support in the direction perpendicular to the transport direction by the transport means is longer than the width of the electrode sheet in the direction perpendicular to the transport direction. The ultrasonic processing apparatus according to claim 5 or 6, characterized in that a plurality of the horns are arranged in the width direction of the electrode sheet.

8. The ultrasonic processing apparatus according to claim 7, characterized in that the plurality of horns are arranged such that their ends overlap when viewed from the transport direction.

9. The ultrasonic processing apparatus according to claim 1 or 5, further comprising a preheating means for preheating the active material layer of the electrode sheet.

10. The ultrasonic processing apparatus according to claim 1 or 5, characterized in that the electrode sheets are a positive electrode sheet and a negative electrode sheet for a lithium-ion battery.

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