Cutting apparatus and cutting method

Abstract

The cutting apparatus includes a conveying section that conveys a continuous body (8) of a plurality of electrode plates (10); a laser scanning section that scans the continuous body (8) by laser; and a control section that controls the laser scanning section. The control section controls the laser scanning section (4) so that the continuous body (8) is divided into a first portion and a second portion by forming a plurality of unit cutting sections (38) continuously while intermittently irradiating laser while scanning the continuous body (8). The unit cutting section (38) has a main line section (44) extending along a boundary between the first portion and the second portion and a bent section (46) extending from an end of the main line section (44) in a bent manner.

Description

Technical Field

[0001] This disclosure relates to a cutting device and a cutting method. Background Technology

[0002] In recent years, with the increasing popularity of electric vehicles (EVs), hybrid electric vehicles (HVs), and plug-in hybrid electric vehicles (PHVs), shipments of secondary batteries for automotive use have increased. In particular, shipments of lithium-ion secondary batteries have increased. Furthermore, beyond automotive applications, secondary batteries are also gaining popularity as power sources for portable devices such as laptops. For example, Patent Document 1 discloses a method for cutting electrode plates using laser technology while continuously conveying them in a roller-to-roll manner.

[0003] [Prior Technology Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-33912 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] Examples of methods for cutting electrode plates include the so-called "one-stroke writing" method, which involves continuously scanning the electrode plate with a laser and cutting it at continuous cutting sections, and the so-called "on-the-fly" method, which involves intermittently scanning the electrode plate with a laser and joining multiple unit cutting sections (cutting segments) to cut the electrode plate.

[0008] While a single-stroke writing method can reliably cut the electrode plate, the laser output is highly dependent on the delivery speed. For example, a slow delivery speed results in excessive heat input to the electrode plate, potentially causing it to burn. Therefore, in a single-stroke writing method, the laser intensity needs to be meticulously adjusted to match the delivery speed of the electrode plate, making the laser output control program extremely complex and difficult to manufacture.

[0009] In contrast, the real-time method simplifies laser output control. However, in the real-time method, the cutting quality is highly dependent on the transport speed. For example, if the electrode plate is transported at a high speed, multiple cut sections may be difficult to join, potentially resulting in burrs at discontinuous cut sections. Since burrs on the electrode plate can cause short circuits, they are associated with reduced secondary battery quality. In recent years, in particular, the demand for faster lead times and higher throughput in secondary battery production has led to a trend towards higher electrode plate transport speeds. Consequently, the cutting quality of the electrode plate is more prone to deterioration.

[0010] This disclosure was made in view of the above circumstances, and one of its objectives is to provide a technique for suppressing the reduction in cutting quality when cutting electrode plates.

[0011] [Technical solutions used to address technical problems]

[0012] One aspect of this disclosure is a cutting device. The cutting device includes: a transport section for transporting a continuous body of multiple electrode plates; a laser scanning section for scanning the continuous body with a laser; and a control section for controlling the laser scanning section. The control section controls the laser scanning section to divide the continuous body into a first part and a second part by scanning the continuous body while intermittently irradiating it with a laser, forming a continuous plurality of unit cutting sections. Each unit cutting section has a main line extending along the boundary between the first part and the second part and a bent section extending from the end of the main line section.

[0013] Another aspect of this disclosure is a cutting method. This cutting method includes the following steps: conveying a continuous body of multiple electrode plates, and dividing the continuous body into a first part and a second part by scanning the continuous body while intermittently irradiating it with a laser, thereby forming a continuous series of unit cut portions. Each unit cut portion has a main line portion extending along the boundary between the first part and the second part, and a bent portion extending from the end of the main line portion.

[0014] Any combination of the above-mentioned constituent elements, and any way of converting the present disclosure into methods, apparatus, systems, etc., are also valid forms of the present disclosure.

[0015] [Invention Effects]

[0016] According to this disclosure, it is possible to suppress the reduction in cutting quality when cutting electrode plates. Attached Figure Description

[0017] Figure 1 This is a perspective view schematically representing the cutting device of Embodiment 1.

[0018] Figure 2 (A) is a schematic diagram representing the trajectory of the laser. Figure 2 (B) is a schematic diagram showing the shape of the unit cut-off portion of the reference example. Figure 2 (C) is a schematic diagram showing the shape of the unit cut-off portion in Embodiment 1.

[0019] Figure 3 This is a schematic diagram showing the shape of the unit cut-off portion in Embodiment 2. Detailed Implementation

[0020] The present disclosure will now be described based on preferred embodiments and with reference to the accompanying drawings. These embodiments are illustrative rather than limiting, and not all features and combinations thereof described in the embodiments constitute the essential content of the present disclosure. Identical or equivalent constituent elements, components, and processes shown in the various drawings are labeled with the same reference numerals, and repetitive descriptions are omitted where appropriate. Furthermore, the scales and shapes of the parts shown in the figures are conveniently set for ease of explanation and are not interpreted as limiting unless specifically mentioned. Additionally, the use of terms such as "first," "second," etc., in this specification or claims does not indicate any order or importance unless specifically mentioned, but is used to distinguish one component from others. Furthermore, in the accompanying drawings, some less important components are omitted from the description of the embodiments.

[0021] (Implementation Method 1)

[0022] Figure 1 This is a perspective view schematically illustrating the cutting device of Embodiment 1. The cutting device 1 includes a conveying unit 2, a laser scanning unit 4, and a control unit 6. The conveying unit 2 is a mechanism for conveying the continuous body 8. The conveying speed is, for example, 1 m / min to 100 m / min. The laser scanning unit 4 is a mechanism for performing cutting processing on the continuous body 8 by scanning the continuous body 8 with a laser L. The control unit 6 is a mechanism for controlling the laser scanning unit 4. In this embodiment, the direction of flow of the continuous body 8 at the position where the continuous body 8 is cut by the laser scanning unit 4 is defined as the conveying direction A of the continuous body 8. For example, the conveying direction A is vertically downward.

[0023] The continuous body 8 in this embodiment is a long, strip-shaped component in the transport direction A, having a structure in which multiple electrode plates 10 are connected. For example, the continuous body 8 has a structure in which the electrode plates 10 are arranged in two rows and multiple columns. Each electrode plate 10 has a structure in which an electrode active material layer is stacked on a current collector plate. In the case of a typical lithium-ion secondary battery, the current collector plate is made of aluminum foil or the like if it is the positive electrode, and is made of copper foil or the like if it is the negative electrode. In addition, in the case of a typical lithium-ion secondary battery, the electrode active material is lithium cobalt oxide, lithium iron phosphate, or the like if it is the positive electrode, and graphite or the like if it is the negative electrode. After the continuous body 8 has undergone cutting processing based on the laser scanning unit 4, each electrode plate 10 is provided with a protruding portion 12. The protruding portion 12 protrudes from the current collector plate of the electrode plate 10 toward the width direction B of the continuous body 8. The width direction B is orthogonal to the transport direction A.

[0024] The continuous body 8 has a coated portion 14 of electrode active material and a non-coated portion 16 of electrode active material. The coated portion 14 is disposed at the center of the continuous body 8 in the width direction B. The coated portion 14 corresponds to the electrode active material layer. The coated portion 14 is obtained by applying an electrode paste of electrode active material to the surface protrusions of the plate constituting the current collector using a known coating apparatus. The non-coated portions 16 of electrode active material are disposed at both ends of the continuous body 8 in the width direction B. The non-coated portions 16 are the exposed portions of the plate constituting the current collector, which are formed into protrusions 12 by cutting based on the laser scanning portion 4. Furthermore, at the boundary between the coated portion 14 and the non-coated portion 16, for example, an oxide layer for protecting the coated portion 14 may be provided. This oxide layer is preferably provided on the electrode plate 10 constituting the positive electrode.

[0025] The conveying unit 2 continuously conveys the continuous body 8 to a position opposite to the laser scanning unit 4 via a feed roller (not shown). The cutting device 1 of this embodiment includes two laser scanning units 4 arranged in the width direction B. One laser scanning unit 4 irradiates a laser L onto the uncoated portion 16 at one end of the conveyed continuous body 8. The other laser scanning unit 4 irradiates a laser L onto the uncoated portion 16 at the other end of the conveyed continuous body 8. This cuts the uncoated portions 16 on both sides to form protrusions 12. Furthermore, when the continuous body 8 is a continuous body with arranged negative electrode plates, a portion of the coated portion 14 can also be cut during the cutting process based on the laser scanning unit 4. Additionally, when the continuous body 8 is a continuous body with arranged positive electrode plates, a protective layer (not shown) is provided at the boundary between the coated portion 14 and the uncoated portion 16. This protective layer is, for example, an oxide layer of the metal constituting the current collector. In this case, during the cutting process based on the laser scanning unit 4, a portion of the protective layer, except for the coated portion 16, can also be cut. Alternatively, in addition to coating portion 16, a portion of coating portion 14 and a portion of protective layer can also be cut off.

[0026] The conveying unit 2 has a chamber 18. The chamber 18 suppresses sputtering and dust generated during the cutting process by the laser L from adhering to the continuous body 8, the cutting device 1, or floating in the atmosphere. Alternatively, the chamber 18 may be omitted.

[0027] The continuous body 8, after being cut by the laser scanning unit 4, is divided into a product section 26 and a waste section 28. The product section 26 includes a plurality of continuous electrode plates 10 and a plurality of tabs 12 formed from a portion of the uncoated section 16. Each tab 12 is arranged one-to-one with respect to each electrode plate 10. The waste section 28 is the portion of the uncoated section 16 that, as a tab 12, does not remain on the product section 26 side. The product section 26 is conveyed to the next process line. The waste section 28 is conveyed in a direction different from the product section 26 and is cut off from the product section 26.

[0028] The laser scanning unit 4 includes a laser oscillator 34 and a scanning mechanism 36. The laser oscillator 34 can be a known fiber laser, or a pulsed laser oscillator. The scanning mechanism 36 receives laser light L incident from the laser oscillator 34. The scanning mechanism 36 can employ a known mechanism, such as a current scanner. The scanning mechanism 36 has a mirror (not shown) rotatably supported by two motors with axes in two directions. Rotating the mirror in the X-axis and Y-axis directions allows scanning of the laser L in the XY plane. The scanning mechanism 36 is not limited to a 2D scanner; it can also be a 3D scanner that applies scanning in the focal point (Z-axis) direction. In this case, scanning in the Z-axis direction is achieved by moving a collimating lens in the Z-axis direction. The scanning mechanism 36 can change the irradiation direction of the laser L by rotating the mirror while irradiating the continuum 8. The driving of the laser oscillator 34 and the scanning mechanism 36 is controlled by the control unit 6.

[0029] The control unit 6, as a hardware component, is implemented by components and circuits, such as the computer's CPU and memory; as a software component, it is implemented through computer programs, etc. Figure 1 In this context, the terms are described as functional modules implemented through their collaboration. Those skilled in the art will understand that these functional modules can be implemented in various forms through a combination of hardware and software.

[0030] Figure 2 (A) is a schematic diagram representing the trajectory of laser L. Figure 2 (B) is a schematic diagram showing the shape of the unit cut-off portion of the reference example. Figure 2 (C) is a schematic diagram showing the shape of the unit cut-off portion in Embodiment 1.

[0031] The control unit 6 controls the laser scanning unit 4 to divide the continuous body 8 into a first part and a second part by intermittently irradiating the laser L while scanning the continuous body 8. That is, the control unit 6 controls the laser scanning unit 4 to perform cutting processing on the continuous body 8 in an instantaneous manner.

[0032] In each irradiation area of ​​the intermittent irradiation of the laser L, the laser scanning unit 4 aligns the irradiation position of the laser L with the predetermined irradiation start point of the continuous body 8, and begins scanning the continuous body 8 with the laser L. The laser scanning unit 4 rotates the reflector of the scanning mechanism 36, causing the irradiation position of the laser L to shift upstream in the transport direction A. When the irradiation position of the laser L reaches the predetermined irradiation end point, the laser scanning unit 4 stops the irradiation of the laser L. Thus, a unit cutting section 38 is formed.

[0033] As the continuous conveying of the continuous body 8 continues, the formed unit cut section 38 flows downstream in the conveying direction A. The laser scanning unit 4 returns the irradiation position of the laser L to the irradiation start point at a speed faster than the conveying speed of the continuous body 8. Then, when the upstream end of the unit cut section 38 formed in the previous irradiation segment, i.e., the irradiation end position of the laser L in the previous irradiation segment, reaches the irradiation start point, the laser scanning unit 4 begins irradiation of the laser L in the next irradiation segment. The control unit 6 can determine the situation of the irradiation end position of the previous irradiation segment reaching the irradiation start point based on the conveying speed of the continuous body 8 and the elapsed time.

[0034] By repeatedly performing the above actions, such as Figure 2 As shown in (A), the trajectory 40 of the laser L segment, in other words, the unit cutting portion 38, is continuous, and the continuous body 8 is divided into a product portion 26 as the first part and a waste portion 28 as the second part. In the portion of the continuous body 8 corresponding to the tab portion 12, a trajectory 40 is drawn that curves outward along the contour of the tab portion 12 in the width direction B. Thus, a tab portion 12 protruding from the electrode plate 10 in the width direction B is formed. Each tab portion 12 is formed by one trajectory 40 (unit cutting portion 38). In the continuous body 8, in the portion corresponding to the connection region 42 where two adjacent tab portions 12 in the transport direction A will be connected, multiple straight trajectories 40 are drawn. Thus, multiple straight unit cutting portions 38 are joined to form a straight connection region 42. The connection region 42 extends parallel to the transport direction A.

[0035] like Figure 2 In the reference example shown in (B), where each unit cut section 38 is composed only of a main line section 44 extending along the boundary between the product section 26 and the waste section 28, the unit cut sections 38 may become discontinuous when adjacent unit cut sections 38 are offset in the width direction B. In contrast, as... Figure 2 As shown in (B), the unit cutting section 38 of this embodiment has a main line section 44 extending along the boundary between the product section 26 and the waste section 28, and a bent section 46 extending from the end of the main line section 44. Each bent section 46 extends outward from the end of the main line section 44 in the width direction B. Therefore, even if adjacent unit cutting sections 38 are offset in the width direction B, the bent sections 46 of each unit cutting section 38 can intersect each other. As a result, adjacent unit cutting sections 38 can be made continuous.

[0036] For example, in the straight unit cut section 38 constituting the connecting region 42, the main line section 44 is a straight line extending parallel to the conveying direction A. The bend section 46 extends from both ends of the main line section 44 in a direction intersecting the direction in which the main line section 44 extends, i.e., in a direction intersecting the conveying direction A. In the curved unit cut section 38 constituting the tab section 12, the main line section 44 has a curved portion protruding in the width direction B and a straight portion located at the bottom of the bend and extending parallel to the conveying direction A. This straight portion constitutes part of the connecting region 42. The bend section 46 extends from the end of the straight portion of the main line section 44 in a direction intersecting the conveying direction A. Furthermore, the bend section 46 can be straight or curved.

[0037] The tab 12 is formed by cutting off the uncoated portion 16. Additionally, Figure 2 The connection region 42 shown in (C) is formed by cutting off the uncoated portion 16. However, the location of the connection region 42 is not limited to the uncoated portion 16. When the continuous body 8 is an arrangement of negative electrode plates, the connection region 42 can also be formed by cutting off the end in the width direction B of the coating portion 14. That is, the unit cut portion 38 forming the connection region 42 can also be disposed on the coating portion 14. In this case, at least the main line portion 44 of the unit cut portion 38 is disposed on the coating portion 14. In addition, when the continuous body 8 is an arrangement of positive electrode plates, the connection region 42 can be formed by cutting off the protective layer, or it can be formed by cutting off the end in the width direction B of the coating portion 14. That is, the unit cut portion 38 forming the connection region 42 can also be disposed on the protective layer or the coating portion 14. In this case, at least the main line portion 44 of the unit cut portion 38 is disposed on the protective layer or the coating portion 14.

[0038] As explained above, the cutting device 1 of this embodiment includes: a conveying section 2 for conveying a continuous body 8 of multiple electrode plates 10; a laser scanning section 4 for scanning the continuous body 8 with a laser L; and a control section 6 for controlling the laser scanning section 4. The control section 6 controls the laser scanning section 4 to divide the continuous body 8 into a first part and a second part by scanning the continuous body 8 while intermittently irradiating it with the laser L. Each unit cutting section 38 has a main line section 44 extending along the boundary between the first part and the second part and a bent section 46 extending from the end of the main line section 44.

[0039] By providing a bending portion 46 in the unit cut portion 38, even if two adjacent unit cut portions 38 are offset in a direction intersecting with the adjacent direction, the two unit cut portions 38 can be made continuous by intersecting each other with the bending portions 46. Therefore, since the generation of burrs in the first and second cut portions can be suppressed, the reduction in the cutting quality of the electrode plate can be suppressed. Thus, the quality of the secondary battery can be maintained, and production lead time and throughput can be improved.

[0040] Furthermore, in this embodiment, the continuous body 8 is a long strip in the transport direction A, having a coated portion 14 of electrode active material and a non-coated portion 16 of electrode active material. The coated portion 14 is disposed at the center of the continuous body 8 in the width direction B, which is orthogonal to the transport direction A, and the non-coated portion 16 is disposed at the end of the continuous body 8 in the width direction B. The control unit 6 controls the laser scanning unit 4 to form a plurality of tabs 12 arranged at predetermined intervals in the transport direction A, at least by cutting off the non-coated portion 16. At least a portion of the bending portion 46 extends outward in the width direction B. Therefore, the bending portion 46 can suppress the possibility of the end of the electrode plate 10 being cut off.

[0041] (Implementation Method 2)

[0042] Embodiment 2 has the same configuration as Embodiment 1, except that the protruding portion 12 is formed by multiple unit cut portions 38. Hereinafter, this embodiment will be described with a focus on the configuration that differs from Embodiment 1, and the common configuration will be briefly described or omitted.

[0043] Figure 3 This is a schematic diagram showing the shape of the unit cut-off portion 38 in Embodiment 2. (Example) Figure 3 As shown, in this embodiment, the tab portion 12 is edged with a plurality of unit cut portions 38. Specifically, the tab portion 12 is formed by two generally L-shaped unit cut portions 38 and one straight unit cut portion 38. The L-shaped unit cut portion 38 has a portion extending in the transport direction A and a portion extending in the width direction B, with the portion extending in the width direction B forming the side portion of the tab portion 12. The portion extending in the transport direction A forms part of the connecting region 42. In addition, the top of the tab portion 12 extending in the transport direction A is formed by the straight unit cut portion 38.

[0044] Both the L-shaped unit cut portion 38 and the straight unit cut portion 38 have bent portions 46 at both ends. Furthermore, these unit cut portions 38 are continuous because the bent portions 46 at the outer end of the L-shaped unit cut portion 38 in the width direction intersect with the bent portions 46 of the straight unit cut portion 38. The bent portions 46 at the opposite end of the L-shaped unit cut portion 38 intersect with the bent portions 46 of the straight unit cut portion 38 constituting the connecting region 42.

[0045] In the unit cutting section 38 located in the connection area 42 where two adjacent tabs are connected in the transport direction A, the bending section 46 extends outward in the width direction B. This bending section 46 prevents the end of the electrode plate 10 from being cut off. On the other hand, in the unit cutting section 38 located at the top of the tab 12 in the width direction B, the bending section 46 extends inward in the width direction B. This bending section 46 prevents the waste section 28 from being cut off. By preventing the waste section 28 from being cut off, it is possible to prevent the waste section 28 from being transported together with the product section 26 without separating from it. Furthermore, if the waste section 28 is not cut off due to its large width and thickness or being made of a high-strength material, the bending section 46 at the top of the tab 12 can be oriented outward in the width direction B.

[0046] The embodiments of this disclosure have been described in detail above. The above embodiments are merely examples illustrating specific ways of implementing this disclosure. The content of the embodiments does not limit the technical scope of this disclosure; various design changes, such as alterations, additions, and deletions of constituent elements, can be made within the scope of the spirit of this disclosure as defined by the claims. New embodiments with applied design changes possess the respective effects of both the combined embodiments and variations. In the above embodiments, the content enabling such design changes is emphasized by markings such as "in this embodiment" or "in this embodiment," but design changes are also permitted even without such markings. Any combination of the above constituent elements is also valid as a form of this disclosure. The shaded lines marked on the cross-sections of the drawings are not intended to limit the material of the objects marked with shaded lines.

[0047] In various embodiments, the first part is the product section 26 and the second part is the waste section 28, but it is not limited to this. For example, the first part and the second part can also be the electrode plate 10. In addition, the continuous body 8 can also be a state in which the electrode plate 10 and the partition are stacked. In addition, the non-coating section 16 can also be provided only on one side of the continuous body 8.

[0048] The invention described above can also be specified by the items described below.

[0049] [Project 1]

[0050] A cutting method includes the following steps:

[0051] A continuous body (8) conveying multiple electrode plates (10), and

[0052] By intermittently irradiating the continuum (8) with a laser (L) while scanning the continuum (8), a series of unit cut-off sections (38) are formed, dividing the continuum (8) into a first part and a second part;

[0053] The unit cut-off section (38) has a main line section (44) extending along the boundary between the first part and the second part and a bent section (46) extending from the end of the main line section (44).

[0054] [Industrial Availability]

[0055] This disclosure can be used for cutting devices and cutting methods.

[0056] [Explanation of reference numerals in the attached figures]

[0057] 1 Cutting device, 2 Conveying section, 4 Laser scanning section, 6 Control section, 8 Continuous body, 10 Electrode plate, 12 Protrusion section, 14 Coating section, 16 Uncoated section, 38 Unit cutting section, 42 Connecting area, 44 Main line section, 46 Bending section.

Claims

1. A cutting device, comprising: A transport unit that transports a continuous body of multiple electrode plates. The laser scanning unit of the continuum is used for laser scanning, and Control unit that controls the laser scanning unit; The control unit controls the laser scanning unit to scan the continuum while intermittently irradiating it with a laser, thereby forming a series of continuous unit cut-off sections to divide the continuum into a first part and a second part. The unit cut portion has a main line portion extending along the boundary between the first portion and the second portion, and a bent portion extending from the end of the main line portion. The continuous body is a long strip-shaped structure in the conveying direction, having a coated portion of electrode active material and a non-coated portion of the electrode active material. The coated portion is located at the center of the continuous body in the width direction orthogonal to the conveying direction, and the non-coated portion is located at the ends of the continuous body in the width direction. The control unit controls the laser scanning unit to at least cut off the uncoated portion, forming a plurality of tabs spaced apart at predetermined intervals in the transport direction. The unit cutting portion located in the connection area where two adjacent tabs in the conveying direction will be connected has the bent portion. In the unit cut-off portion located in the connection area where two adjacent tabs are connected in the conveying direction, the bend extends outward in the width direction; In the unit cut portion located at the top of the tab portion in the width direction, the bent portion extends inward in the width direction.

2. The cutting device as described in claim 1, The main line section is straight; The bent portion extends in a direction that intersects with the direction in which the main line extends.

3. A cutting method, comprising the following steps: A continuous body that transports multiple electrode plates. By intermittently irradiating the continuum with a laser while scanning it, a series of continuous unit cut-off sections are formed, dividing the continuum into a first part and a second part; The unit cut portion has a main line portion extending along the boundary between the first portion and the second portion, and a bent portion extending from the end of the main line portion. The continuous body is a long strip-shaped structure in the conveying direction, having a coated portion of electrode active material and a non-coated portion of the electrode active material. The coated portion is located at the center of the continuous body in the width direction orthogonal to the conveying direction, and the non-coated portion is located at the ends of the continuous body in the width direction. The cutting method includes the following steps: controlling the laser scanning section to cut at least the uncoated section to form a plurality of tabs spaced apart at predetermined intervals in the transport direction. The unit cutting portion located in the connection area where two adjacent tabs in the conveying direction will be connected has the bent portion. In the unit cut-off portion located in the connection area where two adjacent tabs are connected in the conveying direction, the bend extends outward in the width direction; In the unit cut portion located at the top of the tab portion in the width direction, the bent portion extends inward in the width direction.

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