JP2019012641A - Electrode manufacturing device - Google Patents

Abstract

To provide an electrode manufacturing device that can suppress an active material mixture from being applied to a position at which warpage of lengthy metal foil is caused.SOLUTION: An electrode manufacturing device 20 comprises: a carrying device that carries lengthy metal foil 18 in a longitudinal direction; and a slit-type coating device 30 that discharges an active material mixture 12a through a discharge port 34 of a slit 33 and applies the active material mixture 12a to a side further inside than both ends in a short direction in the lengthy metal foil 18. Further, the electrode manufacturing device 20 comprises a tension applicator 40. The tension applicator 40 has a feeding roller 42 that feeds an exposed part 18a exposed toward both ends in the short direction of the lengthy metal foil 18 to outside in the short direction while tucking the part from both sides in a thickness direction thereof and applies tension to the part. The feeding roller 42 is arranged side by side with the slit 33 along a longitudinal direction of the discharge port 34 in the slit 33.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electrode manufacturing apparatus including a slit type coating apparatus and a tension applying apparatus.

  Conventionally, as a power storage device mounted on a vehicle such as an electric vehicle (EV) or a plug-in hybrid vehicle (PHV), there are a lithium ion secondary battery, a nickel hydride secondary battery, and the like. The power storage device includes an electrode assembly in which electrodes (positive electrode and negative electrode) each having an active material layer on the surface of a metal foil overlap each other in a state where a separator is interposed therebetween. As the electrode assembly, a stacked type formed by stacking a large number of individual electrodes is known, and a stacked power storage device including such an electrode assembly is also known.

  The manufacture of the electrode used for the stacked type power storage device is performed by applying an active material mixture obtained by kneading an active material, a conductive additive, a binder, and a solvent to a long metal foil to be conveyed to form a coating part. The coated part is dried. In the coating process, the active material mixture is not applied to the edges along the longitudinal direction of the long metal foil, and the exposed metal foil is exposed at both ends in the short direction of the long metal foil. The part is formed in the longitudinal direction of the long metal foil. Thereafter, the coated part is pressed to increase the active material density, and then cut into individual electrodes to produce an electrode.

  By the way, in the long metal foil, there is a case where warp occurs in the short direction due to sagging due to its own weight while being conveyed, and the active material mixture is applied to the long metal foil in a state where the warp has occurred. And the charge / discharge reaction in the resulting electrode is not preferable. Then, the method of forming an active material layer in the state which pulled long metal foil from the transversal direction both sides and suppressed curvature (for example, refer to patent documents 1).

  In patent document 1, the elongate metal foil conveyed is made to run to the vapor deposition area | region for forming an active material layer. In the vapor deposition region, width direction tension generators are arranged on both sides of the long metal foil in the short direction (width direction). And the active material layer is formed in the state which suppressed the curvature of long metal foil by providing the tension | tensile_strength toward the short direction outer side to long metal foil with the width direction tension generator.

JP 2008-41515 A

  However, in patent document 1, there exists a possibility that curvature may generate | occur | produce in the conveyance direction upstream and downstream rather than the location where the tension | tensile_strength in long metal foil was provided. And in patent document 1, formation of an active material layer is performed by vapor deposition, and the vapor deposition area | region has extended to the conveyance direction upstream and downstream rather than the location where tension | tensile_strength was provided in long metal foil, There is a possibility that the active material mixture may be deposited on the portion where the warp has occurred in the foil.

  The objective of this invention is providing the electrode manufacturing apparatus which can suppress that the active material mixture is apply | coated to the location where the curvature of long metal foil generate | occur | produced.

  An electrode manufacturing apparatus for solving the above-mentioned problems includes a transport device that transports a long metal foil in the longitudinal direction, and discharges an active material mixture from a discharge port of a slit. The slit-type coating device for applying the active material mixture on the inner side, and the exposed portions of the long metal foil exposed on both ends in the short-side direction, while sandwiching from both sides in the thickness direction to the outside in the short-side direction A tension applying device having a feed roller that feeds and applies tension, wherein the discharge port of the slit has a length extending in a short direction of the long metal foil, and the feed roller is a length of the discharge port. The gist is that it is arranged alongside the slit along the direction.

  According to this, tension | tensile_strength toward the short direction outer side of long metal foil can be provided with a feed roller, and generation | occurrence | production of the curvature along the transversal direction of long metal foil can be suppressed with a tension | tensile_strength provision apparatus. Since the feed roller for suppressing the occurrence of warpage and the discharge port of the slit are arranged side by side, the active material mixture is applied to the portion of the long metal foil where the occurrence of warpage is suppressed, and as a result, warpage It can suppress that an active material mixture is apply | coated to the location which generate | occur | produced.

  In the electrode manufacturing apparatus, the tension applying device includes a drive source that rotates the feed roller and a control device that controls the drive source, and the control device rotates the feed roller by the drive source. The drive source so that the feed amount of the long metal foil per unit time in the longitudinal direction assumed at the time is larger than the feed amount of the long metal foil per unit time by the transport device To control.

  According to this, when it is assumed that the long metal foil can be freely fed in the longitudinal direction, the control device causes the feed amount of the long metal foil by the feed roller to be larger than the feed amount by the transport device. When the driving source is controlled, the feed roller can be idled with respect to the exposed portion, and slippage of the feed roller with respect to the exposed portion can be generated. Then, dynamic friction occurs between the exposed portion and the feed roller. Compared with the case where the feed roller rotates with the long metal foil and static friction occurs between the feed roller and the exposed portion, the friction generated at the exposed portion can be reduced. As a result, the force for sandwiching the long metal foil can be reduced.

  In the electrode manufacturing apparatus, one of the feed rollers that sandwich the exposed portion may be rotated by the drive source, and the other feed roller may be rotated by the long metal foil.

  According to this, as compared with the case where both feed rollers are rotated by the drive source, the force for sandwiching the exposed portion is more easily controlled when only one feed roller is rotated by the drive source.

In the electrode manufacturing apparatus, each of the pair of feed rollers may be rotated by a driving source.
According to this, both feed rollers can be idled with respect to the exposed portion, and slippage of both feed rollers with respect to the exposed portion can be generated. Therefore, the friction which generate | occur | produces in an exposed part can be made small and the force which pinches | interposes a long metal foil can be made small.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that an active material mixture is apply | coated to the location where the curvature of long metal foil generate | occur | produced.

The perspective view which shows an electrode. The schematic diagram which shows an electrode manufacturing apparatus. The perspective view which shows a slit type coating apparatus and a tension | tensile_strength provision apparatus. The sectional side view which shows a slit type coating apparatus. The top view which shows a tension | tensile_strength provision apparatus. The perspective view which shows the tension | tensile_strength provision apparatus of another example.

Hereinafter, an embodiment in which an electrode manufacturing apparatus is embodied will be described with reference to FIGS.
First, a secondary battery as a power storage device including electrodes will be described. Although not shown, the secondary battery is a square battery having a square appearance. The secondary battery is a lithium ion battery. The secondary battery includes an electrode assembly in a case. The electrode assembly is configured by laminating a plurality of positive electrodes and a plurality of negative electrodes alternately with the electrodes insulated from each other.

  As shown in FIG. 1, each of the positive electrode 10 and the negative electrode 10 has a rectangular shape. The electrode 10 includes an active material layer 12 on both surfaces of a rectangular metal foil 11 (a positive electrode is an aluminum foil and a negative electrode is a copper foil). The electrode 10 includes an uncoated portion 11a where the active material layer 12 does not exist along one long edge portion. The electrode 10 includes a tab 13 having a shape protruding from a part of the long edge portion along the uncoated portion 11a.

Next, a method for manufacturing the electrode 10 will be described.
The manufacturing method of the electrode 10 is a coating method in which an active material mixture obtained by kneading an active material, a conductive additive, a binder, and a solvent is continuously applied to the surface of a strip-shaped long metal foil to form a strip-shaped coating portion. It accompanies the construction process and the coating process, and includes a drying process in which the coating part is heated to evaporate the solvent contained in the active material mixture and to cure the binder. Furthermore, the manufacturing method of an electrode includes the pressurization process which compresses a coating part and raises an active material density, and the cutting process which cut | disconnects a coating part and an exposed part in the shape of a piece of electrode.

Next, the electrode manufacturing apparatus 20 which manufactures the electrode material 17 which is the precursor of the electrode 10 by performing the said coating process and drying process is demonstrated.
As shown in FIG. 2, the electrode manufacturing apparatus 20 forms the coating part 19 by apply | coating the active material mixture 12a to the conveying apparatus 21 which conveys the elongate metal foil 18 to a longitudinal direction, and the elongate metal foil 18 A slit coating device 30, a tension applying device 40 that applies tension to the long metal foil 18, and a drying device 50 that dries the coating unit 19.

  The transport device 21 includes a supply reel 22. The long metal foil 18 is wound around the supply reel 22 with the longitudinal direction extending in the circumferential direction of the supply reel 22. The supply reel 22 is rotatably supported by a support device (not shown).

  Further, the transport device 21 includes a take-up reel 23. The long metal foil 18 is wound with the longitudinal direction extending in the circumferential direction of the take-up reel 23. The take-up reel 23 is rotatably supported by a support device (not shown). When the long metal foil 18 supplied from the supply reel 22 is wound around the rotating take-up reel 23, the long metal foil 18 is conveyed in the longitudinal direction at a constant feed speed. The feed speed is a feed amount of the long metal foil 18 per unit time. The feed speed of the long metal foil 18 is determined by the feed speed of the long metal foil 18 from the supply reel 22 and is controlled by the support device of the supply reel 22. A direction in which the long metal foil 18 is conveyed is defined as a conveyance direction X.

  The electrode manufacturing apparatus 20 includes a first tension roller 24 a on the downstream side of the supply reel 22 in the conveyance direction X of the long metal foil 18. The first tension roller 24a changes the direction so that the long metal foil 18 supplied obliquely upward from the supply reel 22 is conveyed in the horizontal direction.

  The electrode manufacturing apparatus 20 includes a second tension roller 24 b on the upstream side of the take-up reel 23 in the transport direction X of the long metal foil 18. The second tension roller 24b changes the direction so that the long metal foil 18 to be conveyed is directed to the take-up reel 23 obliquely below.

  The slit type coating device 30 is disposed on the downstream side of the first tension roller 24 a in the transport direction X of the long metal foil 18. The slit type coating apparatus 30 is disposed above the long metal foil 18 so as to face one side of the long metal foil 18. The slit type coating apparatus 30 applies the active material mixture 12a to one side of the long metal foil 18 to be conveyed.

  As shown in FIG. 3 or FIG. 4, the slit type coating apparatus 30 includes a rectangular parallelepiped body 31. The body 31 includes a lip surface 31a on a lower end surface that is a surface facing the long metal foil 18. The lip surface 31 a has a rectangular shape with the long side extending in the short direction of the long metal foil 18. The lip surface 31a is a flat surface. In the body 31, the direction in which the length of the lip surface 31a extends is defined as the lateral width direction. The body 31 is arranged above the long metal foil 18 so that the width direction extends in the short direction of the long metal foil 18.

  The slit type coating apparatus 30 includes a reservoir 32 for the active material mixture 12 a inside the body 31. The slit coating apparatus 30 includes a slit 33 in the body 31 that communicates with the space of the storage portion 32. The storage part 32 and the slit 33 exist over the entire width direction of the body 31. In the slit 33, the opening facing the lip surface 31a constitutes a discharge port 34 for the active material mixture 12a. The discharge port 34 extends in the width direction of the body 31. A portion of the lip surface 31a on the downstream side of the discharge port 34 in the transport direction X is in contact with the active material mixture 12a discharged from the discharge port 34 to define the coating thickness of the active material mixture 12a. To do.

  As shown in FIG. 5, one end in the longitudinal direction of the discharge port 34 is located inside one end in the short direction of the long metal foil 18, and the other end in the longitudinal direction of the discharge port 34 is short in the long metal foil 18. It is located inside the other end in the direction.

  The active material mixture 12 a pumped from a tank (not shown) by a pump (not shown) flows into the storage part 32 and is spread in the lateral width direction of the body 31 by the storage part 32. The active material mixture 12 a flows into the slit 33 communicating with the space of the storage portion 32 and is discharged from the discharge port 34 of the slit 33.

  The active material mixture 12 a discharged from the discharge port 34 is applied in a straight line to a portion of the long metal foil 18 facing the slit 33. By feeding the long metal foil 18, a coating portion 19 extending in a strip shape is formed on one side of the long metal foil 18. In addition, since both ends in the longitudinal direction of the slit 33 are located inside both ends in the short-side direction of the long metal foil 18, there is a long side outside the coating portion 19 in the short-side direction of the long metal foil 18. An exposed portion 18a formed of the length metal foil 18 itself is formed.

  As shown in FIG. 3 or FIG. 5, the tension applying device 40 is arranged at the same position as the slit coating device 30 in the transport direction X of the long metal foil 18. The tension applying device 40 applies tension to the exposed portion 18 a of the long metal foil 18 toward the outside in the short direction of the long metal foil 18. The tension applying device 40 includes a feed roller 42 that sandwiches each exposed portion 18a from both sides in the thickness direction, a motor 45 as a drive source that rotates the feed roller 42, and a control device 46 that controls the motor 45.

  The feed rollers 42 arranged on both sides of the long metal foil 18 in the short direction face each other in the short direction of the long metal foil 18. The rotation axis L of each feed roller 42 is inclined at a predetermined angle with respect to the transport direction X of the long metal foil 18. Each feed roller 42 can adjust the direction in which the rotation axis L extends. When the feed roller 42 rotates with the exposed portions 18a sandwiched from both sides in the thickness direction, the long metal foil 18 is pulled outward in the short direction, and the occurrence of warpage is suppressed.

  In the feed roller 42, the direction in which the rotation axis L extends is the axial direction. The feed roller 42 has a first end face 42a at one end in the axial direction and a second end face 42b at the other end in the axial direction. One of the feed rollers 42 disposed above the exposed portion 18a is disposed such that the first end surface 42a faces the one end surface 31b in the lateral width direction of the body 31 from an oblique side, The feed roller 42 is arranged such that the first end face 42 a faces the other end face 31 c in the lateral width direction of the body 31 from an oblique side. Each feed roller 42 disposed below the exposed portion 18a is disposed directly below the upper feed roller 42.

  Each feed roller 42 is disposed outside both ends of the body 31 in the lateral width direction. Since the length of the discharge port 34 in the slit 33 extends in the width direction of the body 31, each feed roller 42 is aligned with the slit 33 (discharge port 34) along the length direction of the discharge port 34. In the present embodiment, the slit 33 and the feed roller 42 are arranged in a line in the short direction of the long metal foil 18.

  Of the pair of feed rollers 42 sandwiching the exposed portion 18a, the feed roller 42 above (one side) the exposed portion 18a is rotated by a motor 45 as a drive source, and the feed roller 42 below (the other side) below the exposed portion 18a is The support device 47 is rotatably supported. One feed roller 42 is actively rotated by a motor 45, and the other feed roller 42 is passively rotated, that is, rotated along with the conveyance of the long metal foil 18.

  A control device 46 is signal-connected to the two motors 45 disposed on both sides of the long metal foil 18 in the short direction. The two motors 45 are synchronized by the control device 46 and rotate at the same rotational speed.

  Since the long metal foil 18 is sent out from the supply reel 22 and taken up on the take-up reel 23, the long metal foil 18 cannot be sent freely in the transport direction X. Here, it is assumed that the long metal foil 18 can be sent freely in the longitudinal direction. In this case, when the feed roller 42 is rotated by the motor 45, the amount per unit time that the long metal foil 18 is fed in the transport direction X by the rotation of the feed roller 42 is defined as the feed amount.

  The control device 46 controls the motor 45 so that the feed amount of the long metal foil 18 by the feed roller 42 is larger than the feed amount of the long metal foil 18 by the transport device 21. Note that the feed amount (feed speed) of the long metal foil 18 by the transport device 21 is input to the control device 46, and the control device 46 controls the motor 45 based on the feed amount by the transport device 21.

  Then, the feed roller 42 rotated by the motor 45 idles with respect to the exposed portion 18a, the feed roller 42 slides with respect to the exposed portion 18a, and dynamic friction can be generated between the exposed portion 18a and the feed roller 42. .

  The greater the idling of the feed roller 42, that is, the greater the dynamic friction generated at the exposed portion 18a, the smaller the force that sandwiches the exposed portion 18a by the pair of feed rollers 42. On the other hand, as the idling of the feed roller 42 decreases and the dynamic friction generated in the exposed portion 18a decreases, the state where the static friction is generated approaches and the force for sandwiching the exposed portion 18a by the pair of feed rollers 42 increases. Therefore, by controlling the rotation speed of the motor 45 and the magnitude of dynamic friction, the force for sandwiching the long metal foil 18 can be adjusted.

  The electrode manufacturing apparatus 20 includes a drying apparatus 50 on the downstream side of the slit type coating apparatus 30 in the transport direction X. A high-temperature heat medium (for example, a gas such as air or nitrogen gas) is supplied from the outside into the drying device 50.

  In the drying process, the coating unit 19 is dried while passing through the inside of the drying device 50. As a result, the solvent contained in the active material mixture 12a evaporates and the binder is cured by heat, so that the active material and the conductive auxiliary agent are fixed to each other. As a result, the electrode material 17 having the long metal foil 18 and the coating part 19 is manufactured.

Next, the manufacturing method of the electrode material 17 will be described together with the operation of the electrode manufacturing apparatus 20.
As shown in FIG. 2, the long metal foil 18 supplied from the supply reel 22 is wound around the take-up reel 23 while being supported by the first tension roller 24a and the second tension roller 24b, and at a constant feeding speed. It is conveyed in the conveyance direction X. Then, the active material mixture 12 a is applied to the surface of the long metal foil 18 by the slit coating device 30.

  The feed roller 42 that sandwiches the exposed portions 18 a applies a tension toward the outer side in the short-side direction of the long metal foil 18 to the application site of the active material mixture 12 a on the long metal foil 18. Therefore, the active material mixture 12a is applied to a portion where the occurrence of warpage in the long metal foil 18 is suppressed. Then, by applying the active material mixture 12a, the coating portion 19 and the exposed portion 18a are formed, and the electrode material 17 is formed. The electrode material 17 is conveyed in the longitudinal direction in the drying device 50, and the coating part 19 is cured. Thereafter, the long metal foil 18 is taken up on the take-up reel 23.

According to the above embodiment, the following effects can be obtained.
(1) In the electrode manufacturing apparatus 20, the feed rollers 42 of the tension applying device 40 are arranged in a line along the longitudinal direction of the discharge port 34 of the slit 33. For this reason, the active material mixture 12a can be applied to the portion where the long metal foil 18 is pulled outward in the short direction by the feed roller 42. Therefore, it can suppress that the active material mixture 12a is apply | coated to the location where curvature generate | occur | produced in the long metal foil 18. FIG.

  (2) Of the pair of feed rollers 42 sandwiching the exposed portion 18a, one of the feed rollers 42 is rotated by the motor 45, and the feed roller 42 is slid relative to the exposed portion 18a. For example, the friction generated in the exposed portion 18a can be reduced compared to the case where static friction is generated between the exposed portion 18a and the feed roller 42 as in the case where the feed roller 42 is rotated around the long metal foil 18 being conveyed. it can. As a result, the force for sandwiching the long metal foil 18 by the feed roller 42 can be reduced, and damage to the long metal foil 18 due to the sandwiching can be suppressed.

  (3) By controlling the rotation speed of the motor 45, the dynamic friction generated in the exposed portion 18a can be adjusted. Therefore, by adjusting the rotation speed of the motor 45 in accordance with the material of the long metal foil 18, it is possible to suppress damage due to the force that sandwiches the long metal foil 18.

  (4) Of the pair of feed rollers 42 sandwiching the exposed portion 18a, one of the feed rollers 42 is rotated by the motor 45, and the other is rotated by the exposed portion 18a. Therefore, since only one feed roller 42 is actively driven, the force for sandwiching the exposed portion 18a by the pair of feed rollers 42 can be easily controlled.

In addition, you may change the said embodiment as follows.
As shown in FIG. 6, a motor 45 as a drive source may be connected to both of the pair of feed rollers 42 that sandwich the exposed portion 18 a, and each feed roller 42 may be rotated by the motor 45. If comprised in this way, both the feed rollers 42 can be idled with respect to the exposed part 18a, and the slip of both the feed rollers 42 can be generated with respect to the exposed part 18a. Therefore, the friction generated in the exposed portion 18a can be reduced, and the force for sandwiching the long metal foil 18 can be reduced.

  ○ Of the pair of feed rollers 42 that sandwich the exposed portion 18a, the upper feed roller 42 is rotated by the motor 45, but the lower feed roller 42 is rotated by the motor 45, and the upper feed roller 42 is lengthened. The shank metal foil 18 may be rotated.

  In the case where the active material mixture 12 a is applied to both surfaces of the long metal foil 18 by the slit type coating device 30, tension may be applied to the long metal foil 18 by the tension applying device 40.

(Circle) the electrode manufacturing apparatus 20 of embodiment is not provided with the drying apparatus 50, and may be comprised by the slit type coating apparatus 30, the conveying apparatus 21, and the tension | tensile_strength provision apparatus 40. FIG.
The tension applying device 40 may have a configuration including only the feed roller 42. In this case, the feed rollers 42 arranged in a line along the longitudinal direction of the discharge port 34 of the slit 33 are rotated with the conveyance of the long metal foil 18 while being outside in the short direction with respect to the long metal foil 18. Apply tension toward

  Of the feed rollers 42 of the tension applying device 40, the feed rollers 42 disposed above the long metal foil 18 may be rotatably supported by the body 31 of the slit type coating device 30.

The power storage device may be applied to another power storage device such as an electric double layer capacitor instead of the secondary battery.
In the embodiment, the stacked type is described as the electrode assembly, but a wound type may be used.

  The secondary battery is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery. In short, any material may be used as long as ions move between the positive electrode active material and the negative electrode active material and transfer charge.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(1) The said conveying apparatus is an electrode manufacturing apparatus provided with the supply reel which sends out the said long metal foil, and the winding reel which winds up the sent said long metal foil.

  12a ... Active material mixture, 18 ... Long metal foil, 18a ... Exposed part, 20 ... Electrode manufacturing device, 21 ... Conveying device, 30 ... Slit coating device, 33 ... Slit, 34 ... Discharge port, 40 ... Tension Giving device, 42 ... feed roller, 45 ... motor as drive source, 46 ... control device.

Claims (4)

A transport device for transporting a long metal foil in the longitudinal direction;
A slit type coating device that discharges the active material mixture from the slit outlet and applies the active material mixture inside the both ends in the short direction of the long metal foil,
A tension applying device having a feed roller for applying tension by feeding the exposed portions of the long metal foil exposed at both ends in the short-side direction to the outside in the short-side direction while being sandwiched from both sides in the thickness direction;
The discharge port of the slit has a long side extending in a short direction of the long metal foil,
The electrode manufacturing apparatus, wherein the feed roller is arranged alongside the slit along a longitudinal direction of the discharge port.   The tension applying device includes a drive source that rotates the feed roller and a control device that controls the drive source, and the control device is assumed when the feed roller is rotated by the drive source. 2. The drive source is controlled such that a feed amount of the long metal foil per unit time in the longitudinal direction is larger than a feed amount of the long metal foil per unit time by the transport device. The electrode manufacturing apparatus as described.   3. The electrode manufacturing apparatus according to claim 2, wherein one of the feed rollers sandwiching the exposed portion is rotated by the drive source, and the other feed roller rotates along with the long metal foil.   The electrode manufacturing apparatus according to claim 2, wherein each of the pair of feed rollers is rotated by a driving source.