JP2016021283A - Winding device and manufacturing method of electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a winding device capable of generation of creases and lateral displacement even when winding an electrode material in which a coated part with an active material layer disposed on the surface thereof and a non-coated part where no active material layer is disposed are mixed, and a manufacturing method of an electrode.SOLUTION: A winding device 10 includes: an unwinding roll 11 for unwinding an electrode material 70; a winding roll 13 for winding the electrode material; a discrimination section 30 for mutually discriminating a product part 77 in which the active material layer is disposed and a lead part 73 where the active material layer is not disposed, on a surface of a metal foil 71 of the electrode material; and a dancer roll 15 of which the swing position is controlled in such a manner that, when winding the lead part around the winding roll, a tensile force to be applied to the electrode material becomes smaller in comparison with winding the product part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a winding device and an electrode manufacturing method.

  In the manufacturing process of electrodes used for secondary batteries such as lithium ion batteries and electric double layer capacitors, electrodes are manufactured through various processes such as a coating process, a pressing process, an inspection process, and a punching process. In the manufacturing process, a winding device including at least a pair of rolls that unwinds, conveys, and winds a substrate or an electrode material on which an active material layer is formed is used. Once the substrate or electrode material is unwound, it passes through one or a plurality of steps, is then wound around a roll again, and is transported to the next step.

  In such a winding device, it is required to prevent so-called “winding deviation” such as deviation of the roll in the rotation axis direction at the time of winding the base material. For example, the posture of the roll for winding It is known to control. In addition, one of the causes of winding slip is also known to be due to excessive tightening. This is due to the fact that the wound electrode material on the inner side slides against the stress on the outer peripheral side when the outer side is tightly wound. For example, Patent Document 1 describes that the pressing force of the nip roll is changed with the change of the coil diameter of the winding coil to prevent excessive winding tightening.

JP 2012-129147 A

  In addition to the above-described conventional winding device, there is also known a winding device capable of winding while preventing winding slippage even with a relatively small tension by controlling the posture of the roll for winding. However, displacement of the electrode material also occurs other than winding displacement. The electrode material after the pressing step has a surface that is more slippery at the coated portion where the active material layer is formed than before the pressing step. For this reason, when the roll after the pressing process is wound and transported, even if it is wound with the same tension as that of the winding roll before the pressing process, the axial displacement of the electrode material easily (hereinafter, Such a shift is referred to as “lateral shift”). Such a lateral shift can be suppressed by increasing the tension during winding. However, if the tension is increased to the extent that lateral displacement can be completely prevented, wrinkles due to the difference in hardness from the coated part occur in the uncoated part. The electrode material has an uncoated portion (lead portion to be described later) at least at the front end and the rear end even if the coated portion is formed by continuous coating. Such wrinkles are not included in the product, but are not preferable because they tend to be the starting point of the electrode material due to repeated unwinding and winding during the manufacturing process. Further, it is possible to reduce the number of windings as much as possible and ideally perform the punching process without winding the base material once unwound. However, such a process has a great restriction on facility design.

  Therefore, the present invention eliminates wrinkles and lateral displacement even when winding an electrode material in which a coated portion where an active material layer is disposed on the surface and an uncoated portion where no active material layer is disposed are wound. An object of the present invention is to provide a winding device and an electrode manufacturing method that can be suppressed.

  The winding device of the present invention includes an unwinding roll for unwinding an electrode material, a winding roll for winding the electrode material, and a coating portion and an active material in which an active material layer is disposed on a base material of the electrode material The discriminating unit for discriminating between the uncoated portion where the layer is not disposed and the uncoated portion when the uncoated portion is wound on the take-up roll are applied to the electrode material compared to when the coated portion is wound. A tension switching unit that switches the tension so that the tension to be reduced.

  In the method for winding an electrode material according to the present invention, when winding an uncoated portion where the active material layer is not disposed on the surface of the base material in the electrode material, the coated portion where the active material layer is disposed is wound. Compared to the case, the tension applied to the electrode material is reduced and the electrode material is wound up.

  In the winding device of this configuration, the electrode material is applied to the take-up roll according to the slipperiness between the electrode material taken up by the take-up roll and the electrode material that has already been taken up (the electrode material immediately before). The tension applied to the electrode material when winding up is switched. In other words, the tension switching unit applies a greater tension to the electrode material when the coated portion that is slippery with respect to the already wound electrode material is wound than when the uncoated portion is wound. It seems to be. Thereby, the lateral shift | offset | difference at the time of conveyance of electrode material can be suppressed, and it can suppress that the wrinkles resulting from the difference in hardness with a coating part generate | occur | produce in an uncoated part.

  In the winding device of the present invention, the tension switching unit may switch the tension by swinging a dancer roll wound around the electrode material.

  In the winding device having this configuration, the tension applied to the electrode material can be switched with a simple configuration.

  The electrode manufacturing method of the present invention is an electrode that forms a strip-shaped electrode material having a coated portion in which an active material layer is disposed on a substrate and an uncoated portion in which no active material layer is disposed. In the manufacturing method, the electrode material is wound up in a roll shape, and when the uncoated portion is wound, the tension applied to the electrode material is reduced compared to when the coated portion is wound.

  In this electrode manufacturing method, when a coated part that is slippery with respect to an already wound electrode material is wound, a greater tension is applied to the electrode material than when an uncoated part is wound. It seems to be. Thereby, the lateral shift | offset | difference at the time of conveyance of electrode material can be suppressed, and it can suppress that the wrinkles resulting from the difference in hardness with a coating part generate | occur | produce in an uncoated part.

  The method for producing an electrode of the present invention includes a coating process for coating an active material mixture on a substrate and a pressing process for roll pressing an electrode material, and at least at the time of winding after the pressing process The tension when winding the uncoated portion may be made smaller than when winding the portion.

  In this electrode manufacturing method, lateral displacement during transportation can be suppressed even in a state where the friction coefficient of the coated portion surface is reduced by pressing the electrode material.

  The electrode manufacturing method of the present invention has an inspection step after the pressing step of roll-pressing the electrode material, and when winding the uncoated portion, compared to winding the coated portion during winding of the inspection step The tension may be reduced.

  In this electrode manufacturing method, lateral displacement during transportation can be suppressed even in a state where the friction coefficient of the coated portion surface is reduced by pressing the electrode material.

  According to the present invention, even when the electrode material in which the coated portion where the active material layer is disposed on the surface and the uncoated portion where the active material layer is not disposed is wound, wrinkles are generated and laterally shifted. Can be suppressed.

It is a side view showing the schematic structure of the inspection device containing the winding device concerning one embodiment. It is a functional block diagram in the winding device of FIG. It is an expanded view of the electrode material unwound and wound up by the winding apparatus of FIG.

  Hereinafter, an embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings do not necessarily match those described.

  The electrode material of the following embodiment is used for manufacturing electrodes of power storage devices such as secondary batteries and electric double layer capacitors. The electrode manufacturing process includes at least a coating process, a pressing process, and an inspection process. In the coating process, an electrode material described later is coated on a long belt-shaped substrate by a known coating apparatus such as a die coating method to form an electrode material having a coating part. As for the electrode material, the solvent is removed from the coating part by passing through the drying device. In the pressing step, by passing the electrode material through a roll press machine, the active material density of the coated part can be increased and an active material layer is formed. In the inspection process, the presence or absence of defects such as adhesion of foreign matters to the surface or partial peeling of the active material is inspected by sequentially passing the electrode material through the inspection apparatus. In the manufacturing process, a winding device including at least a pair of rolls that unwinds, conveys, and winds a base material or an electrode material is used. The substrate or electrode material that has been unwound is subjected to one or a plurality of steps, and then wound around a roll again. The electrode material wound on the roll is transported by the transport means and transported to the unwinding position in the next process. The surface of the coating part becomes smooth by passing through a roll press in the pressing process, and becomes a slippery state with a small friction coefficient.

  Below, the inspection apparatus 1 provided with the winding device 10 used for an inspection process is demonstrated. The inspection apparatus 1 is an apparatus that inspects the presence or absence of defects on the surface of the electrode material 70 while conveying the electrode material 70. As shown in FIG. 1, the inspection device 1 includes a winding device 10 and an inspection unit 40.

  The winding device 10 includes an unwinding roll 11, a winding roll 13, a dancer roll (tension switching unit) 15, a driven roll 17, a determination unit 30, and a control unit 35 (see FIG. 2). doing. The unwinding roll 11 unwinds the electrode material 70 (refer FIG. 3) in the state wound around the shaft core. The winding roll 13 winds the electrode material 70 fed from the upstream side around the shaft core. The unwinding roll 11 and the winding roll 13 are controlled by a control unit 35 described in detail later.

  A plurality of driven rolls 17 and dancer rolls 15 are arranged between the unwinding roll 11 and the winding roll 13 in the conveyance path of the electrode material 70. The driven roll 17 mainly forms a transport path for the electrode material 70. The dancer roll 15 is configured to be swingable in the left-right direction shown in FIG. 1 about the rotation shaft 15A. In the electrode material 70, a part of the conveyance path is changed by the swing of the dancer roll 15. Thereby, the tension | tensile_strength provided to the electrode material 70 can be switched. The dancer roll 15 is controlled by the control unit 35 described in detail later.

  Here, an electrode material 70 that is unwound, conveyed, and wound by the winding device 10 will be described with reference to FIG. FIG. 3 is a developed view showing the wound electrode material 70 mounted on the unwinding roll 11. Here, the electrode material 70 used for the negative electrode will be described as an example.

  As shown in FIG. 3, the electrode material 70 is a belt-like member extending from the first end 71A to the second end 71B. The first end portion 71 </ b> A is an end portion that is located on the winding core side when attached to the unwinding roll 11. The second end portion 71 </ b> B is an end portion located in the outermost layer when mounted on the unwinding roll 11. Therefore, when the electrode material 70 is unwound from the unwinding roll 11 and is transported, the second end 71B is unwound at the head, and the second end 71B is transported at the head.

  The electrode material 70 is a belt-like material in which an active material layer 75 is disposed on both surfaces of a part of a metal foil (base material) 71 extending in one direction. The metal foil 71 is, for example, a copper foil. The active material layer 75 is made of an active material, a binder (binder), and a conductive additive. Examples of the active material include carbon such as graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, and soft carbon, alkali metals such as lithium and sodium, metal compounds, SiOx (0.5 ≦ x ≦ 1.5 ) And the like, and boron-added carbon. The active material layer 75 is formed by applying an active material mixture composed of an active material, a binder, a conductive additive, and a solvent onto a substrate in a coating process, and then removing the solvent with a drying device.

  The electrode material 70 has a portion where the active material layer 75 is disposed in a width direction orthogonal to the extending direction of the electrode material 70 and a portion where the active material layer 75 is not disposed. Here, the former is referred to as a product part (coating part) 77 and the latter is referred to as a lead part (uncoated part) 73. The product part 77 is a part used as a negative electrode after passing through a predetermined process. The electrode material 70 has lead portions 73 having a predetermined length at both ends.

  The determining unit 30 shown in FIG. 1 is a part that determines whether or not the active material layer 75 is disposed on the surface of the metal foil 71 in the electrode material 70 unwound from the unwinding roll 11. That is, the determination unit 30 is arranged in the vicinity of the unwinding position P1 where the electrode material 70 is unwound from the unwinding roll 11, and the electrode material 70 just unwound from the unwinding roll 11 is the lead portion 73. Or product part 77. For example, the determination unit 30 can use a color detection sensor that can determine the color of the metal foil 71 and the color of the active material layer 75 disposed on the metal foil 71. The determination unit 30 sends determination information indicating whether the electrode material 70 is the lead unit 73 or the product unit 77 to the control unit 35.

  The control unit 35 shown in FIG. 2 is a part that executes various control processes of the operation of the winding device 10, such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a hard disk. Consists of. Various control processes in the control unit 35 are performed by, for example, software in which a program stored in the ROM is loaded onto the RAM and executed by the CPU. Various control processes in the control unit 35 may be executed by hardware such as an electronic circuit.

  The control unit 35 controls driving of the unwinding roll 11 and the winding roll 13. Further, the control unit 35 causes the tension applied to the electrode material 70 to be smaller when the lead portion 73 is wound around the winding roll 13 than when the product portion 77 is wound around the winding roll 13. Switch the tension to. Specifically, the control unit 35 determines the discrimination information sent from the discrimination unit 30, the conveyance speed of the electrode material 70, and between the unwinding position P1 (see FIG. 1) and the winding position P2 (see FIG. 1). Whether the electrode material 70 passing through the winding position P2 is the lead portion 73 or the product portion 77 is determined based on the information such as the transport distance. When the lead part 73 is taken up by the take-up roll 13, the control unit 35 is configured so that the tension applied to the electrode material 70 is smaller than when the product part 77 is taken up by the take-up roll 13. The swing of the dancer roll 15 is controlled.

  The inspection unit 40 is a part that inspects the presence or absence of defects on the surface of the electrode material 70. When the inspection unit 40 detects a defect on the surface of the electrode material 70, the inspection unit 40 sends information to that effect to the control unit 35.

  Next, the operation of the winding device 10 will be described with reference to FIG. When the electrode material 70 wound around the shaft core by the operator is attached to the unwinding roll 11, the unwinding roll 11 starts unwinding of the electrode material 70. The determination unit 30 determines whether the electrode material 70 unwound from the unwinding roll 11 is the lead portion 73 or the product portion 77, and sends the determined determination information to the control unit 35.

  The electrode material 70 fed from the unwinding roll 11 is guided to the inspection unit 40 by the driven roll 17 and the dancer roll 15 and subjected to surface inspection. The electrode material 70 subjected to the surface inspection in the inspection unit 40 is guided to the winding unit 13 by the driven roll 17 and is taken up by the winding roller 13. When the electrode material 70 passing through the winding position P2 is the lead portion 73, the control unit 35 has a tension applied to the electrode material 70 that is about 20% to 30% smaller than that of the product portion 77. Thus, the swing of the dancer roll 15 is controlled.

  In the winding device 10 of the above-described embodiment, according to the slipperiness between the electrode material 70 wound around the winding roll 13 and the electrode material 70 that has already been wound (the electrode material 70 before one turn), The tension applied to the electrode material 70 when the electrode material 70 is wound around the winding roll 13 is switched. In other words, the control unit 35 applies a greater tension to the electrode material 70 when the product portion 77 that becomes slippery with respect to the already wound electrode material 70 is wound than when the lead portion 73 is wound. As shown, the dancer roll 15 is swung. Thereby, it is possible to suppress a lateral shift due to an impact applied when the electrode material 70 is conveyed.

  Here, in order to suppress the lateral displacement, it is conceivable to increase the tension uniformly. However, in this method, as shown in FIG. 3, the wrinkles 70 </ b> A are generated in the lead portion 73 due to the difference in hardness. The lead portion 73 is a portion that is not used for a product (electrode). However, the collar 70A is not preferable because it may become a starting point of breakage of the electrode material when unwinding and winding are repeated in the manufacturing process. In this respect, in the present embodiment, the product portion 77 and the lead portion 73 are distinguished from each other, and switching is performed so that appropriate tension is applied when winding each of the product portion 77 and the lead portion 73. can do.

  Although one embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

  In the above embodiment, the winding device 10 provided in the inspection device 1 has been described as an example, but the present invention is not limited to this. Since the surface of the product part 77 in the electrode material 70 pressed by the roll press apparatus becomes smooth, the difference in frictional resistance between the lead part 73 and the product part 77 increases. Therefore, it is also effective to apply the winding device of the present invention at the time of winding after the pressing step of winding the electrode material 70 after roll pressing.

  In the winding device 10 of the above embodiment, the lead portion 73 and the product portion 77 are discriminated using a color detection sensor that can discriminate the color of the metal foil 71 and the color of the active material layer 75 disposed on the metal foil 71. However, the present invention is not limited to this. For example, the position of the metal foil may be managed by marking a bar code or the like on the side edge of the metal foil. That is, the position of the coated part (product part) and the uncoated part (lead part) may be determined according to a mark for managing the position of the metal foil, and the tension may be changed.

  In the winding device 10 of the above embodiment, the example in which the determination unit 30 is disposed in the vicinity of the unwinding position P1 has been described. However, the present invention is not limited to this, and the conveyance path of the electrode material 70 It may be an arbitrary position in the vicinity.

  DESCRIPTION OF SYMBOLS 1 ... Inspection apparatus, 10 ... Winding device, 11 ... Unwinding roll, 13 ... Winding roll, 15 ... Dancer roll (tension switching part), 17 ... Follower roll, 30 ... Discriminating part, 35 ... Control part, 40 ... Inspection part, 70 ... electrode material, 71 ... metal foil (base material), 73 ... lead part (uncoated part), 75 ... active material layer, 77 ... product part (coated part), P1 ... unwinding position, P2: Winding position.

Claims (5)

An unwinding roll for unwinding the electrode material;
A winding roll for winding the electrode material;
A discriminating unit for discriminating between a coated part in which an active material layer is disposed on an electrode material base material and an uncoated part in which the active material layer is not disposed;
A tension switching unit that switches the tension so that the tension applied to the electrode material is smaller when the uncoated part is wound around the winding roll than when the coated part is wound; ,
A winding device comprising:   The winding device according to claim 1, wherein the tension switching unit switches the tension by swinging a dancer roll wound around the electrode material. In a method for producing an electrode, which forms a strip-shaped electrode material having a coated part in which an active material layer is disposed on a substrate and an uncoated part in which an active material layer is not disposed,
The electrode material is wound in a roll shape, and when winding the uncoated part, the tension applied to the electrode material is reduced compared to when winding the coated part. Production method.   The manufacturing method includes a coating step of coating an active material mixture on a base material, and a pressing step of roll-pressing an electrode material, and at least at the time of winding after the pressing step, The manufacturing method of the electrode of Claim 3 which makes tension | tensile_strength when winding the said uncoated part small compared with the time of winding.   The manufacturing method has an inspection process after a pressing process of roll-pressing an electrode material, and when winding the uncoated part compared to winding the coated part when winding the inspection process. The manufacturing method of the electrode of Claim 3 or 4 which makes tension | tensile_strength small.

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