JP2014103068A - Press device for electrode material and press-processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press device for an electrode material capable of preventing wrinkles from remaining in boundary parts between a covered part and non-covered parts after press-processing and a press-processing method.SOLUTION: An electrode material 12 is configured to have a covered part 13 in which an electrode layer 11 is provided on the surface of a current collector material 10 and non-covered parts 14 in which the electrode layer 11 is not provided on the surface of the current collector material 10, and has the covered part 13 and the non-covered parts 14 formed in a belt-like shape in the longitudinal direction of the current collector material 10. A press device for the electrode material 12 includes: first roll parts 21 for pressing the covered part 13 from both of the front and rear sides; and second roll parts 22 for pressing the non-covered parts 14 from both of the front and rear sides.

Description

  The present invention relates to a pressing device for an electrode material such as a lithium secondary battery, and a pressing method.

For example, in a positive electrode material for forming an electrode such as a lithium secondary battery, an electrode layer is formed by coating on a current collector made of a metal foil such as aluminum. For this reason, the film thickness of the electrode layer may become non-uniform due to variations in the coating amount. As a result, the performance of the material is not brought out, and the capacity density becomes unstable.
Therefore, after coating the electrode layer on the current collector, it is common practice to press the positive electrode material to make the electrode layer uniform in thickness (see, for example, Patent Document 1). .

JP 2012-059583 A

  However, when the positive electrode material is pressed, pressure is applied to the current collector disposed under the electrode layer, and the current collector is stretched. On the other hand, when there is an uncoated portion where the electrode layer is not applied to the positive electrode material, the uncoated portion is thinner than the coated portion where the electrode layer is applied. It is difficult to apply pressure by pressing to the part. Therefore, wrinkles may occur at the boundary between the coated portion that is stretched by pressing and the non-stretched portion that is not stretched. The wrinkles at the boundary portion may cause erroneous detection in image processing or the like for detecting a non-covered portion of the current collector, which is a subsequent process.

  The present invention has been made in view of the above circumstances, and provides an electrode material pressing device and a pressing method capable of preventing wrinkles from remaining at the boundary between the coated portion and the non-covered portion after pressing. It is to provide.

In order to solve the above problems, the following configuration is adopted.
An electrode material pressing device according to the present invention includes a covering portion in which an electrode layer is provided on the surface of a current collector, and a non-covering portion in which the electrode layer is not provided on the surface of the current collector, and the covering portion And an uncovered portion of the electrode material formed in a strip shape in the longitudinal direction of the current collector, a first roll portion that presses the covered portion from both front and back sides, and the uncovered portion is pressed from both front and back sides. And a second roll part.
With this configuration, when the electrode layer of the covering portion is pressed to make the thickness uniform, even if the current collector of the covering portion is stretched by pressing, the non-covering adjacent to this covering portion The current collector of the part can be stretched by the second roll part. As a result, the current collecting material of the covering portion and the current collecting material of the non-covering portion are stretched equally, and for example, when wrinkles are generated at the boundary portion between the covering portion and the non-covering portion, the wrinkles can be eliminated.

Furthermore, the electrode material pressing device according to the present invention is the electrode material pressing device, wherein the first roll portion and the second roll portion are rotatably provided on the same rotation axis, and the first roll portion The second roll part is formed to have a larger diameter than the first roll part so that the pressure applied to the current collector of the covering part is equal to the pressure applied to the current collector of the non-covering part by the second roll part. May be.
By configuring in this way, since the current collector of the covering portion and the current collector of the non-covering portion are simultaneously stretched, it is possible to prevent the wrinkles from occurring at the boundary portion between the covering portion and the non-covering portion itself. it can.

Furthermore, the electrode material pressing device according to the present invention is the electrode material pressing device, wherein the plurality of covering portions are provided at intervals in the width direction of the electrode material, and the second roll portions are adjacent to each other. You may arrange | position in the position which can press the said non-coating part provided between the said coating | coated parts.
By comprising in this way, each coating | coated part of the electrode material which has a some coating | coated part can be pressed at once, and a relatively large diameter 2nd roll part is arrange | positioned between 1st roll parts. Thus, it can act as a roll crown. As a result, the film thickness of the electrode layer of the covering portion can be made uniform by effectively using the second roll portion as a roll crown.

Furthermore, the electrode material pressing device according to the present invention is the electrode material pressing device, further comprising a width detection unit that detects a width dimension of the covering portion, and the pressing range in the width direction by the second roll unit is It may be possible to change based on the detection result of the width detection unit.
By comprising in this way, the position of a 2nd roll part can be changed so that a coating | coated part may not be pressed. As a result, the covering portion can be prevented from being pressed with an unexpected pressure.

Furthermore, the electrode material pressing device according to the present invention may be configured such that in the electrode material pressing device, the first roll portion and the second roll portion are provided at different positions in the transport direction of the electrode material.
By configuring in this way, for example, even when wrinkles are generated by pressing the covering portion by the first roll portion, it occurs by pressing the non-covering portion by the second roll portion. Wrinkles can be removed. As a result, wrinkles can be prevented from remaining at the boundary portion between the covering portion and the non-covering portion.

Further, the press working method according to the present invention includes a covering portion in which an electrode layer is provided on the surface of the current collector, and a non-covering portion in which the electrode layer is not provided on the surface of the current collector. And the non-covering portion formed in a strip shape in the longitudinal direction of the current collector, the covering portion pressing step of pressing the covering portion of the electrode material, and the covering portion pressing step And a non-covering portion pressing step of pressing the current collector of the non-covering portion so as to have the same pressure as the pressure applied to the current collector of the covering portion.
By doing so, the length of the current collector that is stretched by pressing the covering portion and the length of the current collector that is stretched by pressing the non-covering portion can be aligned. It is possible to prevent wrinkles from remaining on the boundary between the two.

Further, in the press working method according to the present invention, in the press working method, the covering portion pressing step and the non-covering portion pressing step may be performed in parallel.
By doing in this way, since the current collector of the covering portion and the non-covering portion are stretched at the same time, it is possible to prevent the occurrence of wrinkles themselves, and thus it is possible to reduce loads such as fatigue on the current collector. .

  According to the electrode material pressing device and the pressing method according to the present invention, it is possible to prevent wrinkles from remaining at the boundary between the coated portion and the uncoated portion after the pressing.

It is a perspective view which shows the roll-shaped positive electrode material in 1st embodiment of this invention. It is sectional drawing of the positive electrode material which follows the AA line of the said FIG. It is a figure which shows schematic structure of the press apparatus in 1st embodiment of this invention. It is a front view of the press roll in the said press apparatus. It is a front view of the press roll equivalent to FIG. 4 in 2nd embodiment of this invention. It is a front view of the press roll equivalent to FIG. 4 in 3rd embodiment of this invention. It is a front view of the press roll equivalent to FIG. 4 in 4th embodiment of this invention.

Next, the press apparatus in 1st Embodiment of this invention is demonstrated based on drawing.
In this embodiment, a press apparatus that presses a positive electrode material forming a positive electrode plate such as a lithium secondary battery will be described as an example.
A lithium secondary battery or the like has a laminate in which a positive electrode plate and a negative electrode plate are laminated via a separator. The positive electrode plate of such a lithium secondary battery is formed from a long sheet-like positive electrode material 12 as shown in FIGS. The positive electrode material 12 is obtained by applying a layer 11 of an electrode active material (hereinafter simply referred to as an electrode active material layer 11) to a predetermined thickness uniformly on the front and back surfaces of a current collector 10 made of a metal foil such as aluminum. A covering portion 13 is formed.

  Further, uncovered portions 14 where the front and back surfaces of the current collector 10 are exposed without being coated with the electrode active material are formed at both ends in the width direction of the positive electrode material 12. That is, the covering portion 13 and the non-covering portion 14 are formed in a strip shape in the longitudinal direction of the current collector 10. The positive electrode material 12 formed in this way is wound in a roll shape, set in an unwinding device, and unwound and used as necessary. Generally, the unwound positive electrode material 12 is transported by a dedicated transport device and used for the next step such as winding. Here, the battery capacity of the above-described lithium secondary battery is determined mainly depending on the thickness of the electrode active material layer 11. The electrode active material layer 11 is pressed after coating, and is subjected to strict thickness control so that it becomes, for example, about ± 3 microns.

As shown in FIG. 3, the press device 1 of this embodiment includes a pair of press rolls 20a and 20b. These press rolls 20a and 20b are arranged so as to sandwich the conveyed sheet-like positive electrode material 12 from the front and back directions.
As shown in FIG. 4, the pair of press rolls 20 a and 20 b includes a first roll portion 21 in a range where the covering portion 13 is formed in the axial direction. The press rolls 20 a and 20 b include second roll portions 22 on both sides in the axial direction on the same axis as the first roll portion 21.

  Each first roll part 21 of the press rolls 20a and 20b presses the covering part 13 from the front and back sides. A predetermined gap is provided between the first roll portions 21 to make the electrode active material layer 11 have a desired thickness. Here, in general, the current collector 10 is less likely to be plastically deformed than the electrode active material layer 11, but when the electrode active material layer 11 of the covering portion 13 is pressed and stretched by the first roll portion 21. The current collector 10 of the covering portion 13 is also slightly stretched.

  Each 2nd roll part 22 of press roll 20a, 20b is formed in a larger diameter than the 1st roll part 21, and presses the non-coating part 14 from front and back both sides. These second roll portions 22 extend the non-covered portion 14 from the front and back sides so as to extend the current collector 10 of the non-covered portion 14 as much as the current collector 10 of the cover portion 13 slightly stretched by the first roll portion 21. Press. The diameter of the second roll part 22 is such that the pressure applied to the current collector 10 of the covering part 13 by the first roll part 21 is equal to the pressure applied to the current collector 10 of the non-covering part 14 by the second roll part 22. The diameter is set larger than the diameter of the first roll portion 21. That is, the difference between the diameter of the first roll portion 21 and the diameter of the second roll portion 22 is set to be larger than at least the thickness dimension of the electrode active material layer 11 after pressing. A step of pressing the covering portion 13 by the first roll portion 21 and a step of pressing the non-covering portion 14 by the second roll portion 22 as the first roll portion 21 and the second roll portion 22 rotate integrally. Are performed simultaneously (in parallel).

  Therefore, according to the press device of the first embodiment described above, when the electrode active material layer 11 of the covering portion 13 is pressed to make the thickness uniform, the current collector 10 of the covering portion 13 is pressed. Even if stretched, the current collector 10 of the non-covered portion 14 adjacent to the cover portion 13 can be stretched by the second roll portion 22, so the current collector 10 of the cover portion 13 and the current collector of the non-covered portion 14 10 can be stretched equally. As a result, wrinkles can be prevented from remaining at the boundary between the coated portion 13 and the non-coated portion 14 after pressing.

  Further, the first roll part 21 and the second roll part 22 are rotatably provided on the same rotational axis, and the pressure applied to the current collector 10 of the covering part 13 by the first roll part 21 and the second roll part 22 are non-rotated. Since the second roll part 22 is formed to have a larger diameter than the first roll part 21 so that the pressure applied to the covering part 14 is equal, the current collector 10 of the covering part 13 and the non-covering part 14 Since the current collector 10 can be stretched at the same time, it is possible to prevent the wrinkles from occurring at the boundary portion between the covering portion 13 and the non-covering portion 14 itself.

  Further, since the step of pressing the covering portion 13 and the step of pressing the non-covering portion 14 can be performed at the same time, the step of making the film thickness of the electrode active material layer 11 constant while preventing wrinkles from remaining. The time required can be reduced.

Next, the press apparatus in 2nd Embodiment of this invention is demonstrated based on drawing. Note that the pressing device of the second embodiment is different from the pressing device 1 of the first embodiment described above in that the step of pressing the covering portion 13 and the step of pressing the non-covering portion 14 are not performed simultaneously. Therefore, the same parts will be described with the same reference numerals.
As shown in FIG. 5, the press device of the second embodiment includes a pair of first press rolls 220 a and 220 b that press the covering portion 13 of the positive electrode material 12, and a conveying direction more than these first press rolls 220 a and 220 b. And a pair of second press rolls 220c and 220d for pressing the non-covering portion 14 of the positive electrode material 12 are provided. That is, the first press rolls 220a and 220b and the second press rolls 220c and 220d are arranged at different positions in the transport direction.

  The first press rolls 220a and 220b each include a first roll portion 221 formed in a cylindrical shape, and press the covering portion 13 of the positive electrode material 12. The gap between the first roll portions 221 is set to be equal to the gap between the first roll portions 21 of the first embodiment described above. In FIG. 5, the pair of first roll portions 221 disposed so as to sandwich the positive electrode material 12 have the same diameter, but are not limited to the same diameter, and may have different diameters. Further, in FIG. 5, the length dimension of the first roll part 221 is equal to the width dimension of the positive electrode material 12, but may be longer than the width dimension of the covering part 13, for example, longer than the positive electrode material 12. It may be a scale or a short scale.

  Each of the second press rolls 220c and 220d includes a pair of second roll portions 222 for pressing the uncovered portion 14 of the positive electrode material 12 respectively. These second roll portions 222 are provided in the vicinity of both end portions of the rotating shaft 223 extending in the width direction of the positive electrode material 12, and have a width dimension equivalent to that of the non-covered portion 14. In addition, the width dimension of the 2nd roll part 222 should just be a width dimension which can press the non-coating part 14 over the whole area of a width direction, for example, is formed larger than the width dimension of the non-coating part 14, The roll portion 22 may be disposed so as to protrude outward in the width direction of the positive electrode material 12. Moreover, although the case where the 2nd roll part 222 was each provided in the both-ends vicinity of the rotating shaft 223 was demonstrated to an example, you may make it provide a separate rotating shaft for every 2nd roll part 222. FIG.

The press apparatus according to the second embodiment has the above-described configuration. Next, each process by the press apparatus will be described.
First, the sheet-like positive electrode material 12 is unwound from the roll-shaped positive electrode material 12 and sequentially conveyed from the upstream side to the downstream side, and the first roll portions 221 of the first press rolls 220a and 220b. To press the covering portion 13 of the positive electrode material 12 (covering portion pressing step).
Next, the positive electrode material 12 that presses the covering portion 13 is sent to the second press rolls 220c and 220d, and the same pressure as the pressure that acts on the current collector 10 of the covering portion 13 when the covering portion 13 is pressed is the non-covering portion 14. The non-covered portion 14 is pressed by the second press rolls 220c and 220d so as to act on the current collector 10 (non-covered portion pressing step).

Therefore, according to the press apparatus of 2nd Embodiment mentioned above, the 1st press roll 220a, 220b provided with the 1st roll part 221 and the 2nd press roll 220c, 220d provided with the 2nd roll part 222 are respectively simple. For example, the second press rolls 220c and 220d can be added to the existing press device to prevent wrinkles from remaining at the boundary between the covering portion 13 and the non-covering portion 14. can do.
In this embodiment, the example in which the covering portion 13 is first pressed by the first roll portion 221 and then the non-covering portion 14 is pressed by the second roll portion 222 has been shown. The covering portion 14 may be pressed and then the covering portion 13 may be pressed.

Next, the press apparatus of 3rd Embodiment of this invention is demonstrated based on drawing. Since the press device of this third embodiment is configured such that the second roll portion 222 of the press device of the above-described second embodiment can be displaced in the axial direction, the same portions will be described with the same reference numerals.
As shown in FIG. 6, the pressing device of the third embodiment includes a second roll portion 322 that presses the non-covered portion 14. These second roll portions 322 can be displaced in the width direction of the positive electrode material 12 by a slide mechanism (not shown).

  Moreover, the press apparatus of this 3rd Embodiment is equipped with sensors S1-S4 (width detection part) which detects the width direction position of the boundary part of the coating | coated part 13 and the non-coating part 14, These sensors S1-S4 The detection signal is input to the displacement control unit 300.

  The displacement control unit 300 specifies the width of the covering portion 13 based on the detection signals (detection results) of the sensors S1 to S4, and each second roll portion 322 presses the entire width direction of the non-covering portion 14. Thus, drive control of the slide mechanism is performed. Here, as the sensors S1 to S4, various sensors such as a contact sensor and a non-contact sensor can be used. The slide mechanism can be, for example, a motor drive using a ball screw or a mechanism such as a gas cylinder.

  Therefore, according to the press device of the third embodiment described above, the position of the second roll portion 322 is changed so as not to press the covering portion 13 by detecting the boundary portion between the covering portion 13 and the non-covering portion 14. Therefore, it is possible to prevent the covering portion 13 from being pressed with an unexpected pressure.

Next, a press device according to a fourth embodiment of the present invention will be described with reference to the drawings. The press device of the fourth embodiment is different from the first embodiment described above only in that a second roll portion is added, and therefore, the same portions are denoted by the same reference numerals.
As shown in FIG. 7, the positive electrode material 412 of this embodiment has a shape in which two positive electrode materials 12 of the first embodiment described above are aligned in the width direction and integrated.
The positive electrode material 412 is provided with a plurality of, more specifically, two covering portions 13 at intervals in the width direction.

  On the other hand, the pressing device of this embodiment includes two first roll portions 421 that press the covering portion 13 of the positive electrode material 412 and three second roll portions 422 that press the non-covering portion 14. A pair of press rolls 420a and 420b is provided. Of the three second roll portions 422, the second roll portion 422 disposed in the intermediate portion in the width direction is disposed at a position where the uncovered portion 14 provided between the adjacent cover portions 13 can be pressed. Yes.

  The press rolls 420a and 420b are sandwiched from the outside by backup rolls 450a and 450b in order to prevent elastic deformation due to a press load applied to both ends thereof. These backup rolls 450 a and 450 b are provided so as to contact the second roll part 422 without contacting the first roll part 421. The pressure of the press by the 1st roll part 421 and the 2nd roll part 422 is set similarly to the 1st roll part 21 and the 2nd roll part 22 of 1st embodiment mentioned above. In addition, although the case where two covering parts 13 and three non-covering parts 14 are provided has been described, three or more covering parts 13 are provided, and the number of covering parts 13 is equal to the number obtained by adding 1 to the non-covering parts 14. May be provided. In this case, the first roll portion 21 may be disposed at a position facing the covering portion 13 and the non-covering portion 14 may be provided at a position facing the non-covering portion 14.

Therefore, according to the press device of the fourth embodiment described above, each covering portion 13 of the positive electrode material 12 having a plurality of covering portions 13 can be pressed at a time, so that productivity can be improved. Furthermore, since the second roll part 422 having a relatively large diameter can be arranged between the first roll parts 421 and can act as a roll crown, the second roll part 422 can be effectively used as a roll crown to cover the covering part. The film thickness of the electrode layer can be made uniform.
Furthermore, since the backup rolls 450a and 450b are brought into contact with the second roll part 422, the outward displacement of the second roll part 422 sandwiched between the first roll parts 421 can be regulated. , 420b can be efficiently suppressed.

The present invention is not limited to the configuration of each of the above-described embodiments, and the design can be changed without departing from the gist thereof.
For example, in each of the above-described embodiments, the positive electrode material 12 that forms the positive electrode plate of the lithium secondary battery is described as an example of the electrode material. However, the electrode active material layer (electrode layer) 11 is provided on the surface of the current collector 10. Any electrode material may be used, and it may be applied to electrode materials other than lithium secondary batteries. Moreover, although the case where the electrode active material layers 11 were formed on the front and back surfaces of the current collector 10 was described, the electrode active material layers 11 may be provided on either the front or back surfaces. In this case, among the press rolls forming the pair of the first embodiment and the fourth embodiment described above, the press roll on the side where the electrode active material layer 11 is not formed may be a simple cylindrical roll.

  Moreover, in 2nd embodiment mentioned above, although the case where a non-coating part press process was performed after performing a coating part press process was demonstrated, after performing a non-coating part press process, it seems that a coating part press process is performed. It may be. Moreover, in FIG. 5, although the example in which the 2nd roll part 222 was formed in large diameter with respect to the 1st roll part 221 was shown, when not performing a coating | coated part press process and a non-coating part press process simultaneously, Since the distance between the sheet-like positive electrode material 12 and the axis of the first roll part 221 and the distance between the positive electrode material 12 and the axis of the second roll part 222 can be set individually, for example, the first roll The diameter of the part 221 and the second roll part 222 may be the same, or the diameter of the second roll part 222 may be smaller than the diameter of the first roll part 221.

  In the fourth embodiment described above, a case has been described in which one backup roll 450a and 450b is provided on each of the press rolls 420a and 420b. However, a plurality of backup rolls may be provided in an overlapping manner.

  Moreover, in 4th embodiment, although the case where backup roll 450a, 450b did not contact | abut to the 1st roll part 421 was demonstrated, the part facing the 1st roll part 421 of backup roll 450a, 450b is made into the 2nd roll part. The backup rolls 450a and 450b may be formed so as to have a larger diameter than the part that abuts against the 422, and the backup rolls 450a and 450b may abut against both the first roll part 421 and the second roll part 422. Furthermore, you may provide a backup roll with respect to press roll 20a, 20b of 1st embodiment.

10 Current collector 11 Electrode active material layer (electrode layer)
13 Covering part 14 Non-covering part 12 Positive electrode material (electrode material)
21 1st roll part 22 2nd roll part S1-S4 sensor (width detection part)

Claims (7)

A covering portion in which an electrode layer is provided on the surface of the current collector; and a non-covering portion in which the electrode layer is not provided on the surface of the current collector, wherein the covering portion and the non-covering portion are formed of the current collector. In the pressing device for the electrode material formed in a strip shape in the longitudinal direction,
A first roll portion for pressing the covering portion from both front and back sides;
And a second roll portion that presses the uncovered portion from both the front and back sides.   The first roll part and the second roll part are rotatably provided on the same rotation axis, and the pressure applied to the current collector of the covering part by the first roll part and the non-covering part by the second roll part. The press device for an electrode material according to claim 1, wherein the second roll portion is formed to have a larger diameter than the first roll portion so that the pressure applied to the current collector is equal. A plurality of the covering portions are provided at intervals in the width direction of the electrode material,
3. The electrode material pressing apparatus according to claim 2, wherein the second roll portion is disposed at a position where the non-covering portion provided between the adjacent covering portions can be pressed. A width detection unit that detects a width dimension of the covering unit,
4. The electrode material pressing apparatus according to claim 1, wherein a pressing range in the width direction by the second roll portion can be changed based on a detection result of the width detection portion. 5.   The press apparatus of the electrode material as described in any one of Claim 1 to 4 which provided the said 1st roll part and the 2nd roll part in the position which differs in the conveyance direction of the said electrode material. A covering portion in which an electrode layer is provided on the surface of the current collector; and a non-covering portion in which the electrode layer is not provided on the surface of the current collector, wherein the covering portion and the non-covering portion are formed of the current collector. In the press working method of the electrode material formed in a strip shape in the longitudinal direction,
A covering portion pressing step for pressing the covering portion of the electrode material;
A non-covering portion pressing step of pressing the current collector of the non-covering portion so that the pressure applied to the current collector of the covering portion is the same as the pressure applied to the current collector of the covering portion. Method.   The press working method according to claim 6, wherein the covering portion pressing step and the non-covering portion pressing step are performed in parallel.

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