Cutting device and cutting method

Abstract

A cutting device 1 cuts a connection body 4 of an electrode plate 2 having: a current collector plate 12 that has a first surface 12a and a second surface 12b facing away from each other; a first active material layer 14 that is laminated on the first surface 12a; and a second active material layer 16 that is laminated on the second surface 12b. The cutting device 1 comprises: a processing part 8 that cuts the first active material layer 14 and the current collector plate 12 by advancing a cutting blade 26 from the first active material layer 14 side, past the current collector plate 12, to a depth shallower than the surface of the connection body 4 on the second active material layer 16 side thereof; and a support part 10 that faces the processing part 8 with the connection body 4 interposed therebetween, supports the connection body 4, has a groove 30 at a position facing the cutting blade 26 and recessing in a direction away from the processing part 8, and enables removal of a section of the second active material layer 16 overlapping with the groove 30.

Description

[Technical Field]

[0001] The present disclosure relates to a cutting device and a cutting method. [Background technology]

[0002] In recent years, with the spread of electric vehicles (EVs), hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), and other vehicles, shipments of in-vehicle secondary batteries have been increasing. In particular, shipments of lithium-ion secondary batteries have been increasing. In addition to in-vehicle use, secondary batteries are also becoming increasingly popular as power sources for portable devices such as laptop computers.

[0003] An example of a secondary battery includes a laminated electrode assembly in which multiple electrode plates are stacked, and a battery case that houses the laminated electrode assembly and an electrolyte. The electrode plate has a structure in which an electrode active material layer is stacked on the surface of a current collector plate made of metal foil or the like. Regarding such electrode plates, for example, Patent Document 1 discloses an electrode manufacturing facility that transports an electrode material in which an electrode active material is applied to a strip-shaped current collector plate, and continuously forms electrode plates by punching the electrode material with a die roll cutter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-196669 Summary of the Invention [Problem to be solved by the invention]

[0005] As a result of extensive research into the manufacturing method of electrode plates, the inventors have found that there is room for improvement in the conventional manufacturing method in which electrode material is punched out with a die roll cutter in order to improve the quality of electrode plates.

[0006] The present disclosure has been made in light of these circumstances, and one of its objectives is to provide a technique for improving the quality of electrode plates. [Means for solving the problem]

[0007] One aspect of the present disclosure is a cutting device that cuts a continuum of electrode plates having a current collector plate with a first surface and a second surface facing each other, a first active material layer laminated on the first surface, and a second active material layer laminated on the second surface. This cutting device includes a processing unit that cuts the first active material layer and the current collector plate by inserting a cutting blade from the first active material layer side to a depth that exceeds the current collector plate and reaches just before the surface of the continuum on the second active material layer side, and a support unit that supports the continuum and faces the processing unit across the continuum, has a groove facing the cutting blade that is recessed in a direction away from the processing unit, and peels off the portion of the second active material layer that overlaps with the groove.

[0008] Another aspect of the present disclosure is a cutting method for cutting a continuum of electrode plates having a current collector plate with a first surface and a second surface facing each other, a first active material layer laminated on the first surface, and a second active material layer laminated on the second surface. This cutting method includes inserting a cutting blade from the first active material layer side to a depth that goes beyond the current collector plate and just before the surface of the continuum on the second active material layer side to cut the first active material layer and the current collector plate, and supporting the continuum from the second active material layer side with a support part having a groove, and applying the groove to a position facing the cutting blade to peel off the portion of the second active material layer that overlaps with the groove.

[0009] Any combination of the above components, and conversion of the expression of the present disclosure into a method, device, system, etc., are also valid aspects of the present disclosure. [Effects of the Invention]

[0010] According to the present disclosure, the quality of the electrode plate can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of a cutting device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a cutting device. [Figure 3]FIG. 10 is a cross-sectional view schematically showing a cutting device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described below with reference to preferred embodiments and drawings. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are intended to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0013] (Embodiment 1) FIG. 1 is a perspective view of a cutting device 1 according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing the cutting device 1. In FIG. 2, the conveying roll 18 is not shown, and only the cutting blade 26 of the processing unit 8 and only a part of the drum body 22 of the conveying drum 20 are shown. The illustration also shows the continuum 4 extended in a straight line. The cutting device 1 is an apparatus that cuts the continuum 4 of electrode plates 2 into individual pieces into a plurality of electrode plates 2, and includes a conveying unit 6, a processing unit 8, and a support unit 10.

[0014] The continuous body 4 is a strip-shaped body in which a plurality of electrode plates 2 are connected in the conveying direction of the continuous body 4. The continuous body 4 is cut by a processing unit 8 and a support unit 10 to be divided into a plurality of electrode plates 2. The divided electrode plates 2 are alternately stacked with separators sandwiched between them to obtain a stacked electrode body. The obtained stacked electrode body can be used for rechargeable secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, and capacitors such as electric double layer capacitors.

[0015] Each electrode plate 2 has a current collector 12, a first active material layer 14, and a second active material layer 16. The current collector 12 has a first surface 12a and a second surface 12b facing each other. The first active material layer 14 is laminated on the first surface 12a. The second active material layer 16 is laminated on the second surface 12b. Thus, the electrode plate 2 has a three-layer structure in which the current collector 12 is sandwiched between the first active material layer 14 and the second active material layer 16. In a typical lithium-ion secondary battery, the current collector 12 is made of aluminum foil or the like if it is the positive electrode, and copper foil or the like if it is the negative electrode. The first active material layer 14 and the second active material layer 16 can be formed by applying an electrode mixture to the first surface 12a and the second surface 12b of the current collector 12 using a known coating device, followed by drying and rolling. The electrode mixture is obtained by mixing and uniformly dispersing materials such as an electrode active material, a binder, and a conductive material in a dispersion medium. In the case of a typical lithium-ion secondary battery, the electrode active material is lithium cobalt oxide or lithium iron phosphate for the positive electrode, and graphite for the negative electrode.

[0016] The continuum 4 is transported by a transport unit 6. As an example, the transport unit 6 transports the continuum 4 using transport rolls 18, a transport drum 20, or the like. In this embodiment, the transport rolls 18 are arranged upstream of the transport drum 20 in the transport direction of the continuum 4. The transport drum 20 has a cylindrical drum main body 22 and a plurality of holding heads 24 arranged in the circumferential direction of the drum main body 22. The plurality of holding heads 24 have holding surfaces that suction-hold the continuum 4 and the singulated electrode plates 2. The holding surfaces of each holding head 24 face outward from the drum main body 22. The continuum 4 and the singulated electrode plates 2 are transported by the rotation of the drum main body 22 while being suction-held on the holding surfaces of the plurality of holding heads 24.

[0017] The transport roll 18 is arranged so that the peripheral surface of the roll is in contact with the surface of the continuous body 4 facing the first active material layer 14. The transport roll 18 turns the transport direction of the continuous body 4 and delivers it to the transport drum 20. The transport drum 20 transports the continuous body 4 by adsorbing and holding the surface of the continuous body 4 facing the second active material layer 16 with the holding surfaces of each holding head 24. Therefore, the continuous body 4 is transported with the surface facing the first active material layer 14 facing the outside of the drum. A processing unit 8 is arranged on the transport path of the continuous body 4. As an example, the processing unit 8 is arranged so as to face the transport drum 20. The continuous body 4 passes between the transport drum 20 and the processing unit 8 at a position where they face each other, and is then transported downstream of the transport drum 20.

[0018] The processing unit 8 is provided so as to be able to advance and retreat relative to the transport drum 20 in the radial direction of the transport drum 20. The processing unit 8 also has a cutting blade 26 facing the transport drum 20. The cutting blade 26 extends in the width direction of the continuum 4 (a direction perpendicular to the transport direction) so as to overlap the entire continuum 4. The processing unit 8 inserts the cutting blade 26 from the first active material layer 14 side of the continuum 4 to a depth that extends beyond the current collector plate 12 and just before the surface of the continuum 4 on the second active material layer 16 side (the surface facing the transport drum 20). In other words, the cutting blade 26 penetrates the current collector plate 12 but does not penetrate the second active material layer 16. As a result, incisions 28 are formed in the first active material layer 14 and the current collector plate 12, cutting both of them.

[0019] The processing unit 8 inserts the cutting blade 26 into the boundary between two adjacent electrode plates 2. With the continuum 4 held by suction on the conveying drum 20, the boundary is located between two adjacent holding heads 24. The depth of the cutting blade 26 is, for example, about 60 to 80 percent of the thickness of the continuum 4. The processing unit 8 continuously inserts the cutting blade 26 into the continuum 4 sequentially fed by the conveying unit 6.

[0020] The support unit 10 is provided at a position facing the processing unit 8 with the continuum 4 sandwiched therebetween. Therefore, the support unit 10 is also arranged on the transport path of the continuum 4. The support unit 10 supports the continuum 4 from the back side when the cutting blade 26 of the processing unit 8 is pressed against the continuum 4. In this embodiment, the transport drum 20 also serves as the support unit 10. Therefore, the support unit 10 rotates in synchronization with the transport of the continuum 4. By sandwiching the continuum 4 between the cutting blade 26 and the support unit 10, the continuum 4 can be cut more reliably. Furthermore, the accuracy of the penetration depth of the cutting blade 26 can be improved. The support unit 10 may be separate from the transport drum 20.

[0021] Furthermore, the support part 10 has a groove 30 recessed in a direction away from the processing part 8 at a position facing the cutting blade 26. As an example, the groove 30 extends in the width direction of the continuous body 4 so as to overlap the entire cutting blade 26. In this embodiment in which the conveying drum 20 also serves as the support part 10, the groove 30 is provided between two adjacent holding heads 24. Note that the groove 30 is not shown in FIG. 1.

[0022] When cutting blade 26 enters continuum 4 from the side of first active material layer 14 and continuum 4 is pressed against support 10, the portion of second active material layer 16 that overlaps groove 30 is fractured starting from the edge of groove 30 because there is no receiving surface. Then, it peels off from current collector plate 12 and falls into groove 30. As a result, linear peeled portion 32 corresponding to groove 30 is formed in second active material layer 16 at a position opposite cut portion 28.

[0023] In this embodiment, the width W1 of the groove 30 (the size in the conveying direction of the continuum 4) is narrower than the width W2 of the cutting blade 26. This makes it easier for the second active material layer 16 to fracture starting from the edge of the groove 30, making it easier to form the peeled portion 32. The width W1 of the groove 30 is, for example, the width of the portion (opening) that intersects with the surface of the support part 10. The width W2 of the cutting blade 26 is, for example, the width of the cutting edge side end of the belly (blank) of the cutting blade 26. The active material that has fallen into the groove 30 may be collected by a suction mechanism (not shown) or the like.

[0024] By forming the cut portions 28 and the peeled portions 32, the continuum 4 is completely cut and the electrode plates 2 are separated into individual pieces. Each of the separated electrode plates 2 is transported while being held by suction on each holding head 24, and is delivered to a transport mechanism on the downstream side.

[0025] As described above, the cutting device 1 according to the present embodiment is a device for cutting a continuum 4 made up of a plurality of continuous electrode plates 2. Each electrode plate 2 has a structure in which a first active material layer 14 is laminated on the first surface 12a of a current collector plate 12 and a second active material layer 16 is laminated on the second surface 12b. The cutting device 1 includes a processing unit 8 that inserts a cutting blade 26 from the first active material layer 14 side to a depth that extends beyond the current collector plate 12 and just before the surface of the continuum 4 on the second active material layer 16 side to cut the first active material layer 14 and the current collector plate 12, and a support unit 10 that faces the processing unit 8 across the continuum 4 and supports the continuum 4, and has a groove 30 facing the cutting blade 26 that is recessed in a direction away from the processing unit 8, and peels off the portion of the second active material layer 16 that overlaps with the groove 30.

[0026] One method for dividing the continuous body 4 into a plurality of electrode plates 2 is to punch the continuous body 4 from one side using a die roll cutter. However, this method increases the risk of burrs being generated on the cut surface due to friction between the cut surface of the continuous body 4 or the electrode plate 2 and the belly of the cutting blade. Burrs generated on the cut surface can cause short circuits, which can lead to a decrease in battery quality. Furthermore, friction between the cut surface and the belly of the cutting blade can cause the electrode active material layer laminated on the other side of the continuous body 4 to fall off. This fall-off of the electrode active material layer can also lead to a decrease in battery quality.

[0027] In contrast, in the cutting device 1 of the present embodiment, the processing unit 8 advances the cutting blade 26 from the first active material layer 14 side to form an incision 28 in the first active material layer 14 and the current collector plate 12. At the same time, the support unit 10 forms a groove 30 facing the cutting blade 26 to form a peeling portion 32 in the second active material layer 16, thereby cutting the continuum 4. This allows the amount of advancement of the cutting blade 26 into the continuum 4 to be smaller than the thickness of the continuum 4. As a result, friction between the cut surface of the continuum 4 or the electrode plate 2 and the antinode of the cutting blade 26 is reduced, thereby suppressing the generation of burrs. Furthermore, unintended detachment of the electrode active material layer due to friction between the cut surface and the antinode of the cutting blade 26 can be suppressed. This improves the quality of the electrode plate 2.

[0028] If only the first active material layer 14 and the current collector plate 12 were cut without providing the grooves 30 in the support 10, the second active material layer 16 would be cut by the force applied to the continuum 4 by the cutting blade 26 pushing the first active material layer 14 apart, and by the tensile stress applied to the continuum 4 during transport. However, the electrode active material layer is a layer made of compressed powder. Therefore, pulling the second active material layer 16 to cut it could result in an irregular cross section or partial loss. In contrast, in this embodiment, the grooves 30 are provided in the support 10, and the second active material layer 16 is fractured starting from the edges of the grooves 30 to form the peeled portions 32. This ensures the flatness or linearity of the cut surface of the second active material layer 16. This improves the quality of the electrode plate 2.

[0029] It should be noted that tensile stress may be applied to the continuum 4 when it is cut. In the cutting device 1 of this embodiment, tensile stress is applied to the continuum 4 as it is transported. Alternatively, a tensile stress greater than the tensile stress as it is transported may be applied to the continuum 4. By applying tensile stress to the continuum 4, the electrode active material layer can be pulled away from the belly of the blade the moment the continuum 4 is cut. This is expected to have the effect of suppressing shear force from being applied to the electrode active material layer.

[0030] The cutting device 1 of this embodiment also includes a conveying unit 6 that conveys the continuum 4. The processing unit 8 and the supporting unit 10 are disposed on the conveying path of the continuum 4, and form the incisions 28 and peeling units 32 on the successively fed continuum 4. This allows the throughput of the cutting device 1 to be improved.

[0031] Furthermore, the grooves 30 in this embodiment are narrower than the cutting blades 26. This makes it easier for the second active material layer 16 to fracture starting from the edges of the grooves 30, making it easier to form the peeled portions 32. This allows for further improvement in the quality of the electrode plate 2.

[0032] (Embodiment 2) Except for the shape of the processing unit 8, the second embodiment has a common configuration with the first embodiment. Below, the second embodiment will be described focusing on the configuration that differs from the first embodiment, and the common configuration will be described briefly or omitted altogether. FIG. 3 is a cross-sectional view that schematically shows the cutting device 1 according to the second embodiment. In FIG. 3, the transport roll 18 is not shown, and only the cutting blade 26 and a portion of the roll 34 of the processing unit 8, and only a portion of the drum body 22 of the transport drum 20, are shown. The continuum 4 is also shown in a linearly extended state.

[0033] The processing unit 8 in this embodiment has a roll 34 that rotates in synchronization with the conveyance of the continuous body 4. A cutting blade 26 is provided on the peripheral surface of the roll 34. In other words, the processing unit 8 has a die roll cutter. As the roll 34 rotates in synchronization with the conveyance of the continuous body 4, incisions 28 are continuously formed in the continuous body 4 that is sequentially fed by the conveyance unit 6. In addition, a support unit 10 having a groove 30 is disposed at a position opposite the processing unit 8 across the continuous body 4. In this embodiment, the conveyance drum 20 also serves as the support unit 10. The support unit 10 forms a peeling portion 32 in the second active material layer 16 at a position opposite the incision 28.

[0034] The cutting device 1 according to this embodiment can also achieve the same effects as the cutting device 1 according to embodiment 1. Furthermore, the processing unit 8 according to this embodiment has a roll 34 on the circumferential surface of which a cutting blade 26 is provided and which rotates in synchronization with the transport of the continuum 4. This allows the electrode plates 2 to be continuously divided into individual pieces with a simpler configuration.

[0035] The above describes the embodiments of the present disclosure in detail. The above-described embodiments merely illustrate specific examples of implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design modifications, such as changing, adding, or deleting components, are possible within the scope of the concept of the present disclosure defined in the claims. A new embodiment with design modifications will combine the effects of the combined embodiments and modifications. In the above-described embodiments, the content in which such design modifications are possible is emphasized by using notations such as "in this embodiment" or "in this embodiment," but design modifications are also permitted even in content without such notation. Any combination of the above components is also valid as an aspect of the present disclosure. Hatching in cross sections in the drawings does not limit the material of the hatched object.

[0036] The embodiments may be specified by the following items. [Item 1] A cutting device (1) for cutting a continuum (4) of electrode plates (2) each having a current collector plate (12) having a first surface (12a) and a second surface (12b) facing each other, a first active material layer (14) laminated on the first surface (12a), and a second active material layer (16) laminated on the second surface (12b), a processing unit (8) that cuts the first active material layer (14) and the current collector plate (12) by inserting a cutting blade (26) from the first active material layer (14) side to a depth that exceeds the current collector plate (12) and reaches just before the surface of the continuum (4) on the second active material layer (16) side; a support part (10) that faces the processing part (8) across the continuum (4) and supports the continuum (4), and that has a groove (30) recessed in a direction away from the processing part (8) at a position facing the cutting blade (26), and that peels off a portion of the second active material layer (16) that overlaps with the groove (30); Cutting device (1). [Item 2] The width (W1) of the groove (30) is narrower than the width (W2) of the cutting blade (26). Item 1. The cutting device (1) according to item 1. [Item 3] a conveying section (6) for conveying the continuum (4), The processing unit (8) and the support unit (10) are disposed on the conveying path of the continuous body (4). 3. The cutting device (1) according to item 1 or 2. [Item 4] The processing unit (8) has a roll (34) on the circumferential surface of which a cutting blade (26) is provided and which rotates in synchronization with the conveyance of the continuous body (4). Item 3. The cutting device (1) according to item 3. [Item 5] A cutting method for cutting a continuum (4) of electrode plates (2) each having a current collector plate (12) having a first surface (12a) and a second surface (12b) facing each other, a first active material layer (14) laminated on the first surface (12a), and a second active material layer (16) laminated on the second surface (12b), the method comprising: a cutting blade (26) is inserted from the first active material layer (14) side to a depth beyond the current collector plate (12) and just before the surface of the continuum (4) on the second active material layer (16) side, thereby cutting the first active material layer (14) and the current collector plate (12); supporting the continuum (4) from the second active material layer (16) side with a support (10) having a groove (30), and applying the groove (30) to a position facing a cutting blade (26) to peel off the portion of the second active material layer (16) that overlaps with the groove (30); Cutting method. [Industrial Applicability]

[0037] The present disclosure can be used for a cutting device and a cutting method. [Explanation of symbols]

[0038] 1 cutting device, 2 electrode plate, 4 continuum, 6 conveying section, 8 processing section, 10 support section, 12 current collecting plate, 12a first surface, 12b second surface, 14 first active material layer, 16 second active material layer, 26 cutting blade, 30 groove, 34 roll.

Claims

1. A cutting device for cutting a continuum of electrode plates, the continuum having a current collector plate having a first surface and a second surface facing each other, a first active material layer laminated on the first surface, and a second active material layer laminated on the second surface, a processing unit that cuts the first active material layer and the current collector plate by inserting a cutting blade from the first active material layer side to a depth that exceeds the current collector plate and reaches just before the surface of the continuum on the second active material layer side; a support part that faces the processing part across the continuum and supports the continuum, and has a groove that is recessed in a direction away from the processing part at a position facing the cutting blade, and peels off a portion of the second active material layer that overlaps with the groove, The width of the groove is narrower than the width of the cutting blade. Cutting device.

2. a conveying unit that conveys the continuum, the processing unit and the support unit are disposed on a conveying path of the continuous body.

2. The cutting device of claim 1.

3. the processing unit has a roll on the circumferential surface of which the cutting blade is provided and which rotates in synchronization with the conveyance of the continuous body; 3. The cutting device of claim 2.

4. A cutting method for cutting a continuum of electrode plates, the continuum having a current collector plate having a first surface and a second surface facing each other, a first active material layer laminated on the first surface, and a second active material layer laminated on the second surface, the method comprising: a cutting blade is inserted from the first active material layer side to a depth beyond the current collector plate and just before the surface of the continuum on the second active material layer side, thereby cutting the first active material layer and the current collector plate; supporting the continuum from the second active material layer side with a support part having a groove, and applying the groove to a position facing the cutting blade to peel off the portion of the second active material layer overlapping with the groove, The width of the groove is narrower than the width of the cutting blade. Cutting method.

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