JP6142665B2 - Electrode sheet manufacturing method - Google Patents

Description

  The present invention relates to an electrode sheet and a method for manufacturing the electrode sheet, and particularly to a lithium ion secondary battery.

  A lithium ion secondary battery is required to have a high capacity. For this reason, a metal current collector having a three-dimensional network structure that can hold more active material per unit area has been studied. Such a current collector having a three-dimensional network structure needs to be efficiently filled with an active material and further welded with a lead for taking out a current.

  As a method of filling an active material into a current collector having a three-dimensional network structure, a method of immersing a strip having a three-dimensional network structure in a suspension containing the active material is disclosed (for example, Patent Document 1). In Patent Document 1, the band-like body immersed in the suspension is compressed within the elastic limit with a roll in a wet state to remove excess suspension, and the band-like body is dried to form a layer of carbon particles on the surface. To do.

  Moreover, the method of apply | coating a resin varnish to a strip | belt body with the die | dye arrange | positioned at the side surface of the strip | belt-shaped body is disclosed (for example, patent document 2). The method disclosed in Patent Document 2 is a method in which the belt-like body is decompressed from the surface opposite to the surface on which the resin varnish is applied, and the resin varnish penetrates into the belt-like body.

  As a method of welding the lead, a strip-shaped body having a three-dimensional network structure is passed through a roll to form a concave groove portion that is continuously compressed in the longitudinal direction at a constant width on the side of the strip-shaped body, and the lead is placed in the groove portion A method of manufacturing the formed current collector is disclosed (for example, Patent Document 3). Incidentally, the current collector causes welding failure when the active material adheres to the portion where the lead is welded. Further, when the positive electrode active material adheres to a portion where the opposing negative electrode active material is not filled, lithium may be deposited at a portion having the same potential as the negative electrode, which may cause a short circuit. Therefore, it is necessary for the current collector to accurately form an uncoated portion where no active material adheres to the portion where the lead is welded.

Japanese Examined Patent Publication No. 7-52647 (Claim 8, Claim 9, Column 7, line 1 to line 4, FIG. 1) JP 2004-188852 A (Claim 1, paragraphs 0007 to 0008, FIG. 2) Japanese Patent No. 3509031 (paragraph 0004)

  However, the method of Patent Document 1 cannot form a portion where an active material necessary for welding a lead is not applied.

  Moreover, in the method of patent document 2, since resin varnish has high fluidity | liquidity, when apply | filling the filler containing the active material for batteries, there exists a possibility that it cannot fully be filled.

  Furthermore, in the method of Patent Document 3, since the lead welded portion is a groove portion continuous in the longitudinal direction, the area of the uncoated portion increases in proportion to the length of the electrode, and the capacity per electrode decreases. Further, there is a problem that the balance of the load is easily lost on the right and left sides of the roll, and the winding is likely to occur.

  Then, an object of this invention is to provide the manufacturing method and electrode sheet of an electrode sheet which can form an electrical power collector efficiently.

  A first aspect of the present invention includes a porous belt-like body and an active material filled in the belt-like body, and the belt-like body is formed with a groove portion extending in the width direction at a constant interval in the longitudinal direction. The groove is formed by compressing the strip in the thickness direction, and has a portion where the active material is not attached to the surface.

  A second aspect of the present invention is the invention based on the first aspect, characterized in that the opening area of the gap formed in the strip is larger on the other surface than on the one surface.

  According to a third aspect of the present invention, a filler containing an active material is applied to one side surface of the band-shaped body on a porous band-shaped body in which grooves extending in the width direction at regular intervals in the longitudinal direction are formed. It is characterized by that.

  According to a fourth aspect of the present invention, a filler containing an active material is applied to one side surface of the band-like body while forming a groove extending in the width direction with a certain interval in the longitudinal direction in the porous band-like body. It is characterized by that.

  A fifth aspect of the present invention is the invention based on the fourth aspect, wherein the filler is supplied between the convex portions of the pressure roll having a plurality of convex portions, and the pressure roll Is pressed against the surface of the band to form the groove on one side surface of the band, and a filler is applied to one side of the band excluding the groove.

  A sixth aspect of the present invention is an invention based on any one of the third to fifth aspects, wherein suction is performed from the other side surface of the belt-like body.

  A seventh aspect of the present invention is an invention based on the third or fourth aspect, characterized in that the filler is pushed in from a side surface of the band-like body by a roll.

  In the electrode sheet according to the first and second aspects of the present invention, since the active material is not attached to the surface of the groove portion, a lead weld portion having a portion where the active material is not attached can be formed. . Thereby, the lead can be reliably welded to the lead welded portion by welding the lead to the portion where the active material is not attached. Therefore, the electrode sheet can efficiently form a current collector.

  In the method for producing an electrode sheet according to the third to seventh aspects of the present invention, the filler is filled so that the filler does not penetrate, so that the active material adheres to the surface of the lead welded portion formed using the groove. Can be prevented. Thereby, a lead can be reliably welded to a lead welding part. Therefore, the electrode sheet can efficiently form a current collector.

It is a perspective view which shows the structure of the electrical power collector formed from the electrode sheet which concerns on 1st Embodiment of this invention. It is a side view which shows typically the manufacturing apparatus which manufactures the electrode sheet which concerns on 1st Embodiment of this invention. FIGS. 3A and 3B are perspective views showing a manufacturing method of an electrode sheet according to the first embodiment of the present invention in stages, FIG. 3A is a stage where a belt-like body is prepared, FIG. 3B is a stage where grooves 26 are formed, and FIG. It is a figure which shows the stage with which was filled. It is a side view which shows typically the manufacturing apparatus of the electrode sheet which concerns on 2nd Embodiment of this invention. It is a side view which shows typically the manufacturing apparatus of the electrode sheet which concerns on 3rd Embodiment of this invention. It is a side view which shows typically the manufacturing apparatus of the electrode sheet which concerns on 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1. First Embodiment (1) Configuration of Current Collector A current collector 10 shown in FIG. 1 includes an active material holding portion 12 and a lead weld portion 14 formed of a porous plate-like member having an infinite number of voids 11; A lead 16 welded to the lead weld 14. The active material holding part 12 and the lead welding part 14 are formed of, for example, a foamed material of aluminum, an aluminum alloy, stainless steel, or titanium.

  The active material holding unit 12 holds the active material in the gap 11. The opening area of the gap 11 formed in the active material holding portion 12 may be formed such that the surface 15 opposite to the surface 13 is larger than the surface 13 on which the lead welded portion 14 is formed. . The lead welded portion 14 is formed by being compressed in the thickness direction, thereby closing the gap 11. Therefore, the active material is not held in the lead welded portion 14. Further, the surface 17 of the lead welded portion 14 has a portion to which no active material is attached. A lead 16 is welded to a portion of the lead welded portion 14 where no active material is attached. The lead welded portion 14 preferably has no active material attached to the entire surface 17.

(2) Manufacturing apparatus Next, the manufacturing apparatus which manufactures the electrode sheet for forming the electrical power collector 10 comprised as mentioned above is demonstrated. A manufacturing apparatus 19 </ b> A illustrated in FIG. 2 includes a groove forming part 21 and a filling part 23 </ b> A arranged on the downstream side of the groove forming part 21. The groove forming part 21 has a pressure roll 20 and a first support roll 24A, and is arranged so that the porous belt-shaped body 18 travels between the pressure roll 20 and the first support roll 24A. The pressure roll 20 is formed with a plurality of convex portions 22 extending in the width direction of the pressure roll 20 at a predetermined interval. The first support roll 24A has a smooth surface.

  The filling unit 23 </ b> A includes a suction roll 30 and a die 34, and is arranged so that the belt-shaped body 18 travels between the suction roll 30 and the die 34.

  Although not shown, the suction roll 30 includes a cylindrical portion 31 having a plurality of ventilation holes formed on the surface thereof, and an axial core portion 33 disposed concentrically within the cylindrical portion 31. The cylindrical portion 31 is rotatably supported by the shaft core portion 33. A suction portion 32 is formed in the shaft core portion 33. The suction part 32 is arranged to face the die 34 and is connected to an exhaust pump (not shown). Thereby, the suction roll 30 is formed so that air near the surface of the suction part 32 can flow to the exhaust pump through the vent hole through the cylindrical part 31.

  The die 34 is connected to a pressure feed pump (not shown). The pressure pump continuously pumps the filler 36 contained in a tank (not shown) to the die 34. In the present embodiment, the filler 36 is a slurry containing an active material. As a result, the die 34 continuously and uniformly discharges the filler 36 supplied from the pressure pump.

(3) Manufacturing Method Next, a manufacturing method of the current collector 10 configured as described above will be described with reference to the drawings. First, the belt-like body 18 is prepared (FIG. 3A). Although not shown, the belt-like body 18 is wound around a bobbin and is supplied by rewinding the bobbin. The belt-like body 18 is arranged such that the opening area of the gap 11 is larger on the back surface 37 than on the front surface 35.

  Next, the belt-like body 18 travels between the pressure roll 20 and the first support roll 24A (FIG. 2A). Thereby, the groove | channel part 26 extended in the width direction is formed in the strip | belt-shaped body 18 at a fixed space | interval in the length direction (FIG. 3B). In the groove portion 26, the gap 11 is crushed and closed by the structural portion of the band-like body 18.

  Next, the band 18 travels between the suction roll 30 and the die 34 (FIG. 2B). The band 18 has a front surface 35 in contact with the suction roll 30 and a back surface 37 facing the die 34.

  The die 34 continuously and uniformly discharges the filler 36 toward the back surface 37 of the strip 18. The filler 36 discharged from the die 34 is applied to the back surface 37 of the strip 18. The filler 36 applied to the back surface 37 of the band-shaped body 18 is sucked by the suction roll 30 through the band-shaped body 18 so as to penetrate into the gap 11 of the band-shaped body 18 and fill the surface 35. However, since the gap 11 is crushed and closed, the groove 26 does not penetrate the filler 36 and remains on the back surface 37 of the portion where the groove 26 is formed. Thus, the electrode sheet 38 is formed (FIG. 3C). In addition, in order to improve the packing density of the filler 36, the electrode sheet 38 may be compressed in the thickness direction by a roll or the like after filling and drying the filler.

  The electrode sheet 38 is cut into a predetermined size (broken line in FIG. 3C), and the lead 16 is welded to the lead welded portion 14. In this way, the current collector 10 (FIG. 1) can be manufactured from the belt-like body 18.

(4) Action and Effect In the electrode sheet 38 according to the present embodiment, since the filler 36 does not penetrate into the surface 27 of the groove portion 26, the active material is applied to the surface 17 of the lead welded portion 14 formed using the groove portion 26. Can be prevented from adhering. Thereby, the lead 16 can be reliably welded by the lead welding part 14. Therefore, the electrode sheet 38 can efficiently form the current collector 10.

  The band-shaped body 18 is more efficiently filled with the filler 36 by applying the filler 36 to the back surface 37 having a larger opening area than the surface 35 where the lead welds 14 are formed. can do. Furthermore, by applying the filler 36 to the back surface 37, it is possible to more reliably prevent the active material from adhering to the lead welded portion 14.

  By applying the filler 36 to the back surface 37 and sucking the filler 36 with the suction roll 30 from the front surface 35 where the groove 26 is formed, the filler 36 can be more reliably filled into the belt 18. .

  Further, the electrode sheet 38 is formed with the groove portions 26 extending in the width direction of the belt-like body 18 at regular intervals in the length direction to form the lead welded portion 14, thereby minimizing the area of the lead welded portion 14. . Therefore, the electrode sheet 38 can form the current collector 10 having a larger capacity per electrode than in the prior art. Furthermore, since the groove portions 26 extending in the width direction are formed at regular intervals in the length direction, it is easy to maintain the load balance between the left and right sides of the pressure roll 20, so that winding deviation can be prevented.

2. Second Embodiment (1) Manufacturing Apparatus Next, a manufacturing method according to a second embodiment will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the manufacturing apparatus 19 </ b> B according to the present embodiment, the groove forming part 21 and the filling part 23 </ b> B are arranged in the vertical direction, and the belt-like body 18 travels in the vertically downward direction. The groove forming part 21 has a pressure roll 20 and a first support roll 24A, and is arranged so that the strip 18 travels between the pressure roll 20 and the first support roll 24A.

  The filling portion 23B has a second support roll 24B and a dam formation roll 40, and is arranged so that the belt-like body 18 in which the groove 26 is formed travels between the second support roll 24B and the dam formation roll 40. ing. The dam forming roll 40 is disposed on the back surface 37 side of the strip 18 and forms a dam 41 filled with the filler 36 between the back surface 37 of the strip 18. The dam forming roll 40 pushes the filler 36 in the dam 41 into the strip 18 by rotating.

(2) Manufacturing method Next, the manufacturing method of the electrode sheet 38 is demonstrated. First, the strip 18 travels between the pressure roll 20 and the first support roll 24A disposed on the upstream side. As a result, grooves 26 extending in the width direction are formed in the belt-like body 18 at regular intervals in the length direction.

  Subsequently, the vehicle travels between the second support roll 24 </ b> B and the dam forming roll 40 disposed on the downstream side. The filler 36 in the dam 41 is pushed into the band 18 from the back surface 37 by the rotation of the dam forming roll 40. As a result, the filler 36 penetrates into the gap 11 of the strip 18 and fills the surface 35. In addition, since the space | gap 11 is crushed and closed, the groove part 26 does not osmose | permeate, but stays in the back surface 37 of the strip | belt-shaped body 18 in which the groove part 26 is formed. In this way, the electrode sheet 38 is formed from the strip 18.

(3) Action and Effect Since the electrode sheet 38 according to the present embodiment does not penetrate the filler 36 into the surface 27 of the groove 26, the same effect as in the first embodiment can be obtained.

  Moreover, since the manufacturing method of the electrode sheet 38 which concerns on this embodiment decided to inject and fill the filler 36 in the strip | belt-shaped body 18 with the dam formation roll 40, the suction roll 30 which concerns on 1st Embodiment can be abbreviate | omitted. .

3. Third Embodiment (1) Manufacturing Apparatus Next, a manufacturing method according to a third embodiment will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The manufacturing apparatus 19 </ b> C according to the present embodiment includes a pressure roll 20 and a dam forming roll 40. The pressure roll 20 and the dam forming roll 40 are arranged so that the belt-shaped body 18 travels between the pressure roll 20 and the dam forming roll 40 in the vertically downward direction.

(2) Manufacturing method Next, the manufacturing method of the electrode sheet 38 is demonstrated. The belt-like body 18 travels between the pressure roll 20 and the dam forming roll 40 in the vertically downward direction. Thus, the belt-like body 18 is formed with grooves 26 extending in the width direction on the surface 35 by the pressure roll 20 at regular intervals in the length direction. At the same time, the band-like body 18 is filled by the filler 36 being pushed in from the back surface 37 by the dam forming roll 40. In addition, since the space | gap 11 is crushed and the groove | channel part 26 is closed, the filler 36 does not osmose | permeate to the surface 35. FIG. In this way, the electrode sheet 38 is formed from the strip 18.

(3) Action and Effect Since the electrode sheet 38 according to the present embodiment does not penetrate the filler 36 into the surface 27 of the groove 26, the same effect as in the first embodiment can be obtained.

  Moreover, since the manufacturing method of the electrode sheet 38 which concerns on this embodiment decided to inject and fill the filler 36 in the strip | belt-shaped body 18 with the dam formation roll 40, it is the suction which concerns on 1st Embodiment similarly to 2nd Embodiment. The roll 30 can be omitted.

  Furthermore, since the manufacturing method of the electrode sheet 38 according to the present embodiment fills the filler 36 at the same time as forming the groove portion 26, the manufacturing process can be simplified.

4). Fourth Embodiment (1) Manufacturing Apparatus Next, a manufacturing method according to a fourth embodiment will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The manufacturing apparatus 19 </ b> D according to the present embodiment includes a pressure roll 20, a suction roll 30, and a die 34, and is arranged so that the strip 18 travels between the pressure roll 20 and the suction roll 30. Yes. The die 34 is provided above the pressure roll 20 and discharges the filler 36 intermittently. Accordingly, the die 34 supplies the filler 36 to the space 43 between the convex portions 22 of the pressure roll 20. The pressure roll 20 is rotated to form a groove portion 26 in the belt-like body 18 at the convex portion 22, and the filler 36 supplied from the die 34 between the convex portion 22 and the convex portion 22 is grooved in the belt-like body 18. It is applied to a portion where the portion 26 is not formed (a portion between the groove portion 26 and the groove portion 26).

(2) Manufacturing method Next, the manufacturing method of the electrode sheet 38 is demonstrated. The strip 18 travels between the suction roll 30 and the pressure roll 20. Thus, the belt-like body 18 is formed with grooves 26 extending in the width direction on the surface 35 by the pressure roll 20 at regular intervals in the length direction. At the same time, the filler 18 is applied to the surface 35 of the strip 18 by the pressure roll 20. The filler 36 applied to the surface 35 of the strip 18 is sucked by the suction roll 30 through the strip 18 and penetrates into the gap 11 of the strip 18 and fills the surface. In addition, since the filler 36 is supplied to 43 between the convex part 22 and the convex part 22 of a pressure roll, it is not apply | coated to the groove part 26 formed with the convex part 22. FIG.

(3) Action and Effect The electrode sheet 38 according to this embodiment can obtain the same effect as the first embodiment because the filler 36 is not applied to the groove portion 26.

  Furthermore, since the manufacturing method of the electrode sheet 38 which concerns on this embodiment fills the filler 36 simultaneously with forming the groove part 26, the manufacturing apparatus 19D can be simplified.

5). The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the gist of the present invention. For example, a concave groove that is continuous in the longitudinal direction of the strip 18 may be formed.

DESCRIPTION OF SYMBOLS 10 Current collector 11 Space | gap 12 Active material holding | maintenance part 13 Surface 14 Lead welding part 15 Surface 16 Lead | read | reed 17 Surface 18 Strip | belt-shaped body 19A, 19B, 19C, 19D Manufacturing apparatus 20
23A, 23B Filling part 24A First support roll 24B Second support roll 26 Groove part 27 Surface 30 Suction roll 31 Cylindrical part 32 Suction part 33 Shaft core part 34 Die 35 Surface 36 Filler 37 Back surface 38 Electrode sheet 40 Dam forming roll 41 Dam 43 rooms

Claims (4)

Manufacturing an electrode sheet, wherein a filler containing an active material is applied to one side surface of the band-like body while forming a groove extending in the width direction with a certain interval in the longitudinal direction in the porous band-like body Method. The filler is supplied between the convex portions of the pressure roll having a plurality of convex portions, the pressure roll is pressed against the surface of the belt-like body, and the groove portion is formed on one side surface of the belt-like body. to form a manufacturing method of an electrode sheet according to claim 1, wherein applying a filler on one side surface of the strip excluding the groove. Method of manufacturing an electrode sheet according to claim 1 or 2, wherein the aspirating from the other side surface of the strip. Method of manufacturing an electrode sheet according to claim 1, wherein the pushing roll the filler from a side surface of the strip.

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