JP2021003721A - Press device - Google Patents

Abstract

To execute more appropriate continuous press processing in making density of an electrode member higher.SOLUTION: A press device, which continuously presses an electrode member while conveying the member in a conveying direction, comprises: indenters that have planar press surfaces that come into contact with the electrode member; a supporting/moving part that arrays and supports the plurality of indenters and continuously moves the indenters in a conveying direction while putting the indenters in a continuous state in a prescribed press region where the electrode member is pressed by the press surfaces; and an energizing member that energizes the indenters toward the electrode member in the press region.SELECTED DRAWING: Figure 1

Description

This specification discloses a press device.

Conventionally, as a press device of this type, a roll press device that pressurizes an electrode material in which an electrode mixture layer is formed on a current collector has been proposed (see, for example, Patent Document 1). This press device can press the electrode mixture layer by sandwiching it between two opposing rollers to increase the density of the electrode mixture layer.

JP-A-2018-14220

For example, an electrode of a lithium ion battery or the like is generally produced by applying a slurry-like electrode mixture in which an active material, a binder, or the like is mixed on both sides of a metal collecting foil and drying the electrode mixture. However, since the electrode after drying has a low density, the electrode is densified by compression by the roll press device. In this roll press, electrodes are passed through the gap between two rotating cylinders facing each other to increase the density. Originally, the roll press device is a rolling process in which a metal plate or the like is thinned and stretched for a long time. Used for. Therefore, when the electrode is densified by a roll press, the electrode is not only compressed in the thickness direction but also stretched in the plane direction orthogonal to the cylinder. That is, when the electrode density is increased, the thicker the electrode film thickness or the smaller the roll diameter, the greater the stretching action in the plane direction. The electrode has a composite composition, and in particular, since the metal current collector foil is placed in the center, residual stress accumulates in the electrode as the density increases due to differences in stretchability, causing deflection and cracks in the electrode. This may occur, which may reduce durability and safety.

The present disclosure has been made in view of such a problem, and an object of the present disclosure is to provide a press device capable of performing a more appropriate continuous press process when increasing the density of electrode members.

As a result of diligent research to achieve the above-mentioned object, the present inventors have adopted a continuous structure of indenters capable of continuously performing vertical pressing, and further urged the indenter toward the electrode member side. We have found that a more appropriate continuous press can be realized when increasing the density of the electrode members, and have completed the press apparatus of the present disclosure.

That is, the press device of the present disclosure is
A press device that continuously presses while transporting electrode members in the transport direction.
An indenter having a flat press surface in contact with the electrode member,
A support moving portion that arranges and supports a plurality of the indenters and continuously moves the indenters in the transport direction in a predetermined press region that presses the electrode member on the press surface.
An urging member that urges the indenter toward the electrode member in the press region, and
It is equipped with.

In this press device, a plurality of indenters having a flat press surface in contact with the electrode member are continuously moved in the transport direction of the electrode member in a continuous state, and the indenter is moved to the electrode member side by an urging member in a predetermined press region. Encourage and perform continuous pressing. In this pressing device, since the electrode member is continuously pressed by the flat pressing surface formed on the indenter, it is difficult to accumulate residual stress in the transport direction of the electrode member. Further, in this press device, since the indenter is urged toward the electrode member by the urging member, a load can be sufficiently applied to the electrode member even in a state where the indenter is bent, for example. Therefore, in this press device, a more appropriate continuous press process can be performed when increasing the density of the electrode members.

The schematic explanatory view which shows an example of the continuous press apparatus 10. The schematic explanatory view which shows an example of the continuous press apparatus 10. The schematic explanatory view showing an example of a press unit 20 and an indenter 21. The perspective view of the support moving part 30. Explanatory drawing of the chain 33 and the urging roller 36. Explanatory drawing of a roll press and a vertical continuous press. The schematic explanatory view which shows an example of another continuous press apparatus 10B. The schematic explanatory view which shows an example of another continuous press apparatus 10C. The relationship diagram between the electrode thickness and the amount of deflection after pressing. Relationship diagram of penetration angle, elongation, stretching vector and roll diameter at the time of roll press conversion. Explanatory drawing which shows the support moving part 30, 30D of Experimental Examples 1 and 2.

This embodiment will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing a continuous press device 10 which is an example of the present disclosure. The enlarged view of FIG. 1 is a view near the bottom dead center where the press pressure is maximum, and a side view of the indenter 21. 2A and 2B are schematic explanatory views showing an example of the press unit 20, FIG. 2A is a plan view of the support moving portion 30, FIG. 2B is a side view of the support moving portion 30, and FIG. 2C is a front view of the continuous press device 10. FIG. 2D is a side view of the continuous press device 10. FIG. 3 is a schematic explanatory view showing an example of the press unit 20 and the indenter 21. The continuous press device 10 continuously presses the electrode member 11 in a predetermined press region A for pressing the electrode member 11 on the press surface 22 in a direction perpendicular to the transport direction C for transporting the electrode member 11. It is configured as a device including the unit 20. In the continuous press device 10, a moving and fixing mechanism (not shown) is arranged in the main body 18, and the interval between the press units 20 and the approach angle θ can be changed and fixed. The press unit 20 includes an indenter 21, a support moving portion 30, and an urging roller 36. In the present embodiment, the left-right direction, the front-back direction, and the up-down direction will be described as shown in FIGS. 1 to 5.

The electrode member 11 is an object to be pressed by the continuous pressing device 10, and includes a current collector 12 and a mixture layer 13. The electrode member 11 is supported by the base 15 and is conveyed by a conveying portion (not shown). The electrode member 11 may be, for example, a positive electrode member of a power storage device or a negative electrode member. Examples of the power storage device include an alkali metal ion battery using an alkali metal ion (lithium ion or sodium ion) as a carrier, an electric double layer capacitor, an alkali metal ion capacitor, and the like. The current collector 12 is a support that supports the mixture layer 13 and is a member that has conductivity and collects current. The current collector 12 includes, for example, aluminum, titanium, stainless steel, nickel, iron, calcined carbon, conductive polymer, conductive glass, and the like, as well as aluminum for the purpose of improving adhesiveness, conductivity, and oxidation resistance. The surface of or copper may be treated with carbon, nickel, titanium, silver or the like. The current collector 12 is preferably a metal foil. The mixture layer 13 is formed on the surface of the current collector 12, and contains, for example, an active material. The mixture layer 13 may be formed on only one surface of the current collector 12, or may be formed on both surfaces. In the configuration in which the two press units 20 face each other, the electrode member 11 in which the mixture layer 13 is formed on both sides of the current collector 12 can be pressed. The mixture layer 13 is formed by mixing, for example, an active material with a conductive material and a binder as needed, and adding an appropriate solvent to form a paste-like electrode mixture on the surface of the current collector 12. It may be applied and dried. Examples of the active material include sulfides containing a transition metal element, oxides containing an alkali metal element and a transition metal element, and compounds containing an alkali metal element, as the positive electrode active material. Examples of the negative electrode active material include inorganic compounds such as alkali metals, alkali metal alloys and tin compounds, carbonaceous materials capable of occluding and releasing alkali metal ions, composite oxides containing a plurality of elements, and conductive polymers. Be done. The continuous pressing device 10 presses the electrode member 11 after forming the mixture layer 13, and performs a process of increasing the density of the mixture layer 13.

The indenter 21 is a member that presses the electrode member 11, and has a flat pressing surface 22, a support shaft 23, a parallel surface 24, an inclined surface 25, an end surface 26, and an upper surface 27 (FIG. 1, FIG. 3). In the press unit 20, a plurality of arranged indenters 21 are continuous via the chain 33, and a gap is formed in the press surface 22 in a predetermined press region A (see FIG. 1) in contact with the electrode member 11. The electrode member 11 is pressed in sequence. Here, the press region A refers to an region from a position where the press surface 22 comes into contact with the mixture layer 13 to start pressing, to a position where the press surface 22 is separated from the mixture layer 13 and the press ends. Shall be. The support shaft 23 is arranged on both end faces 26 (see FIG. 3) in a direction orthogonal to the transport direction C of the electrode member 11. The support shaft 23 is arranged at a position that does not overlap with the press surface 22, specifically, slightly above the center of the end surface 26. Therefore, the press surface 22 becomes a horizontal plane due to the weight of the indenter 21. A chain 33 is engaged with the support shaft 23, and the indenter 21 is supported by the chain 33 in a continuous state without a gap.

The press surface 22 is the bottom surface of the indenter 21, and is a rectangular plane having a width X whose lateral direction is the lateral direction along the transport direction C and a length Y whose longitudinal direction is orthogonal to the transport direction C. (See FIG. 3). The parallel surface 24 is a plane formed orthogonal to the transport direction C and perpendicular to the press surface 22. The parallel surface 24 controls the posture of the indenter 21 by coming into contact with the parallel surfaces 24 of the adjacent indenters 21. The parallel surface 24 may be formed up to the height of the axis center of the support shaft 23. That is, in the press unit 20, since the indenters 21 adjacent to each other move up and down along the parallel surface 24, the press surface 22 comes into contact with the electrode member 11 while keeping the horizontal while descending in the vertical direction. The inclined surface 25 is a plane continuous with the parallel surface 24 formed on the upper side of the support shaft 23. The inclined surface 25 is formed so as to be inclined inward from the parallel surface 24 when viewed from the end surface 26 (side surface) side. For example, the inclined surface 25 is inside an isosceles triangle connecting the axial center of the first sprocket 31 or the axial center of the second sprocket 32 and the end of the parallel surface 24 (see the alternate long and short dash line in the right enlarged view of FIG. 1). It is formed to enter. Since the indenter 21 has such an inclined surface 25, the indenter 21 is less likely to interfere with the adjacent indenter 21 when moving along a circular orbit such as the first sprocket 31. The upper surface 27 is formed in a convex shape at the center when viewed from the side. The upper surface 27 makes it easy for the urging roller 36 to urge (press) the indenter 21 toward the electrode member 11 in the press region. The indenter 21 has an upper surface 27 having a height Z close to the width X. As described above, the upper surface 27 of the indenter 21 does not have to be formed horizontally with the press surface 22.

In the press region, the indenter 21 has an approach angle θ (see FIG. 1) formed by the angle formed by the track connecting the centers of the press surface 22 and the transport surface of the electrode member 11, and the support interval of the chain 33 is L. The width X of the press surface 22 may satisfy Lcos θ. Further, when the dimensional tolerances of the indenter 21 and the chain 33 at the time of manufacturing are totaled, the value obtained by subtracting Lcosθ from the width X of the press surface 22 of the indenter 21 includes 0, and is more preferably closer to 0. That is, the width X may satisfy Lcos θ in consideration of the dimensional tolerances of the indenter 21 and the chain 33. When the indenter 21 is formed with such a width X, there is no gap between the press surfaces 22 of the indenter 21, and the electrode member 11 can be continuously pressed without forming a seam. The indenter 21 preferably has a width X of the press surface 22 within a range of 10 mm or more and 50 mm or less. In this range, it is easy to uniformly press the electrode member 11. Further, the indenter 21 may have a ratio Z / X of the width X and the height Z of the press surface 22 in the range of 1 or more and 1.5 or less. When the ratio Z / X is 1 or more, the electrode member 11 can be sufficiently pressed, and when the ratio Z / X is 1.5 or less, the height Z becomes lower and the indenter by the pressurizing mechanism (biased roller 36). The pressing force on the upper part can be increased.

The support moving portion 30 moves a plurality of indenters 21 together with the electrode member 11 transported in the transport direction C, and moves the indenter 21 toward the electrode member 11 side in the press region A, and the electrode member 11 on the press surface 22. It is a mechanism to press and press. The support moving portion 30 arranges a plurality of indenters 21 so that the parallel surfaces 24 are adjacent to each other and supports them at a predetermined support interval L, and continuously moves the indenters 21 in the transport direction C in the press region A in a continuous state. The support moving portion 30 may move the indenter 21 in the range where the approach angle θ is 0 ° <θ ≦ 10 ° in the press region A. When the approach angle θ is 10 ° or less, the stretch ratio of the mixture layer 13 in the transport direction C can be further reduced, and the residual stress of the electrode member 11 can be further reduced, which is preferable. From the viewpoint of reducing the residual stress of the electrode member 11, the approach angle θ is more preferably smaller, preferably 8 ° or less, more preferably 5 ° or less, and may be 3 ° or less. From the viewpoint of miniaturization of the device, the approach angle θ is preferably larger, and may be 3 ° or more, or 5 ° or more. The support moving portion 30 includes a first sprocket 31, a second sprocket 32, a chain 33, a drive portion 34, and a support sprocket 35.

The first sprocket 31 is a rotating member whose rotation axis is the first shaft 41. The first sprocket 31 is rotationally driven by the drive unit 34. The first sprocket 31 is arranged on the upstream side (left side in FIG. 1) of the second sprocket 32 with respect to the transport direction C. The first sprocket 31 is provided on both end faces 26 of the indenter 21, and the positions of the sprocket blades of both are synchronized (see FIG. 2A). The second sprocket 32 is a rotating member having a second shaft 42 as a rotating shaft. The second sprocket 32 is driven to rotate via the chain 33 as the first sprocket 31 is driven. The chain 33 is a connecting member that is hung on the first sprocket 31 and the second sprocket 32, meshes with the first sprocket 31 and the second sprocket 32, and moves on a predetermined orbit with their rotation. An indenter 21 is pivotally supported on the chain 33 via a support shaft 23, and the indenter 21 moves in a predetermined trajectory. The chain 33 supports the support shaft 23 on both end faces 26. The drive unit 34 is a motor that rotationally drives the first sprocket 31. The drive unit 34 drives the first sprocket 31 so as to push the indenter 21 in the transport direction C in the press region A. Therefore, the gap between the indenters 21 can be eliminated, and a more uniform press can be performed. The drive unit 34 may be directly connected to the first shaft 41 of the first sprocket 31, or may be meshed with the first sprocket 31 via one or more gears. The drive unit 34 may rotationally drive one or more of the first sprocket 31 and the second sprocket 32. The support sprocket 35 is a support rotating member that is arranged above between the first sprocket 31 and the second sprocket 32 and supports the chain 33. The support sprocket 35 is a member for adjusting the tension of the chain 33, and is pivotally supported by a third shaft 45 that can move and fix in the vertical direction. The third shaft 45 is lowered when the chain 33 and the indenter 21 are removed, and is raised and fixed when the chain 33 is fixed or the chain 33 is slackened.

The urging roller 36 is an urging member that urges the indenter 21 toward the electrode member 11 in the press region A. If the urging member has a roller shape, a load can be smoothly and continuously applied to the indenter 21, which is preferable. The urging roller 36 is arranged on the lower side between the first sprocket 31 and the second sprocket 32. When the urging roller 36 is arranged at this position, the indenter 21 can be slowly lowered to the bottom dead center and the indenter 21 can be slowly raised from the bottom dead center, which is preferable. The urging roller 36 is pivotally supported by a roller shaft 46 at a position where the indenter 21 is below the lower tangent line between the first sprocket 31 and the second sprocket 32. That is, the urging roller 36 is pivotally supported by the roller shaft 46 above the bottom dead center of the indenter 21 in the press region A. The bottom dead center of the indenter 21 is located at the center of the first sprocket 31 and the second sprocket 32. The urging roller 36 may be pivotally supported by a roller shaft 46 having a diameter D larger than the indenter width X. Assuming that the indenter 21 has such a diameter D, a sufficient load can be applied to the indenter 21. In the urging roller 36, the load can be uniformly applied even when the length Y of the indenter 21 is long and the indenter 21 is bent. The urging roller 36 preferably has a ratio W / Y of the length W of the pressure surface 37 (see FIG. 2A) to the length Y of the indenter 21 in the range of 0.5 or more and 1 or less. When the ratio W / Y is 0.5 or more, a sufficient load can be applied to the indenter 21, and when the ratio W / Y is 1 or less, interference with other members of the support moving portion 30 can be further suppressed. This ratio W / Y is preferably larger, more preferably 0.6 or more, and even more preferably 0.8 or more from the viewpoint of applying a load. The urging roller 36 may be driven to rotate with the movement of the indenter 21 and may not have a drive unit, but may be rotationally driven by the drive unit.

Here, the influence of the pressing process between the general roll pressing apparatus and the continuous vertical pressing apparatus will be considered. FIG. 6 is an explanatory view of a roll press (FIG. 6A) and a vertical continuous press (FIG. 6B). As shown in FIG. 6A, since the roll press is rolled, the electrode member 11 to be pressed is compressed in the vertical direction and rolled in the horizontal direction. Therefore, the electrode member 11 contains residual stress, which causes peeling, cutting, bias, and the like. On the other hand, as shown in FIG. 6B, in the continuous vertical press, the electrode member 11 is compressed in the substantially vertical direction, and rolling in the horizontal direction is considerably suppressed. Therefore, in the continuous press device 10 adopting the above-mentioned continuous vertical press method, unlike the roll press, the press surface 22 of the indenter 21 presses against the electrode member 11 in a horizontal state, so that the transfer direction of the electrode member 11 It is difficult to accumulate the residual stress of. It is conceivable to press the electrode member 11 at one time by a batch type vertical press using an indenter having a large area, but it is difficult to realize because it is necessary to apply an extremely large load to the entire indenter. Since the continuous press device 10 uses a plurality of indenters 21, the load applied to one indenter 21 can be small, and the residual stress in the transport direction can be reduced. Therefore, when increasing the density of the mixture layer 13. The occurrence of defects can be further suppressed.

In the continuous press device 10 described in detail above, a plurality of indenters 21 having a flat press surface 22 in contact with the electrode member 11 are continuously moved in the transport direction C of the electrode member 11 in a continuous state, and a predetermined press region A The indenter 21 is urged toward the electrode member 11 by the urging roller 36, and continuous pressing is performed. In this continuous pressing device 10, since the electrode member 11 is continuously pressed by the flat pressing surface 22 formed on the indenter 21, residual stress of the electrode member 11 in the transport direction C is unlikely to be accumulated. Further, in this continuous pressing device 10, since the indenter 21 is urged toward the electrode member 11 by the urging roller 36, the electrode member 11 can sufficiently load the load even in a state where the indenter 21 is bent, for example. Can be called. Therefore, in this continuous pressing device 10, a more appropriate continuous pressing process can be performed when increasing the density of the electrode member 11.

It goes without saying that the present disclosure is not limited to the above-described embodiment, and can be implemented in various embodiments as long as it belongs to the technical scope of the present disclosure.

For example, in the above-described embodiment, the urging member is described as the urging roller 36, but the shape of the roller is not particularly limited as long as the structure can press the indenter 21 toward the electrode member 11. For example, the urging member may have an inclined surface that descends to the bottom dead center, and a structure in which the upper surface 27 of the indenter 21 abuts on the inclined surface may be arranged in the press region A. Even with such an urging member, a more appropriate continuous pressing process can be performed when increasing the density of the electrode member 11.

In the above-described embodiment, the continuous press device 10 has a structure including one press unit 20, but the present invention is not limited to this, and the continuous press device 10 may have a structure in which two press units 20 face each other. .. In the electrode member 11 in which the mixture layer 13 is formed on the front surface and the back surface of the current collector 12, it is more preferable to press with the pressing unit 20 facing each other. In the continuous pressing device 10 in which the press units 20 face each other, the approach angle θ of the indenter 21 may be the same or different in both press units 20. For example, one press unit 20 may be horizontal (approach angle 0 °). The drive speeds of the chains 33 may be the same in the two press units 20.

In the above-described embodiment, the press unit 20 is provided with one urging roller 36, but the present invention is not particularly limited to this, and two or more urging members (biased rollers 36) may be provided. At this time, the most downstream urging roller in the transport direction C may be set to the bottom dead center of the indenter 21. In the press unit provided with the plurality of urging rollers 36, the electrode member 11 can be pressed stepwise.

In the above-described embodiment, the support moving portion 30 includes the first sprocket 31 and the second sprocket 32 as rotating members and the chain 33 as connecting members. However, if the mechanism is such that the indenter 21 is moved by a driving force. It is not particularly limited to this. For example, the connecting member may be a belt, or the sprocket may be a rotating roller. Further, the support moving portion 30 may include two or more support sprockets 35, or the support sprocket 35 may be omitted.

In the above-described embodiment, the press unit 20 is provided with the urging roller 36 between the first sprocket 31 and the second sprocket 32, but the present invention is not particularly limited thereto. FIG. 7 is a schematic explanatory view showing an example of another continuous press device 10B. The same components as those of the continuous press device 10 are designated by the same reference numerals, and the description thereof will be omitted below. The continuous press device 10B has a structure in which the support moving portion 30 in which the chain 33 is inclined and has an oval shape is provided, and the second shaft 42 of the second sprocket 32 also serves as the shaft of the urging roller 36. .. Although FIG. 7 shows a continuous press device 10B having a structure in which two press units 20B face each other, one press unit 20B may be used. Since the continuous press device 10B also has the same indenter 21 as the continuous press device 10, it has the same effect as that of the above-described embodiment. In the press unit 20B, the indenter 21 is separated from the electrode member 11 along the arc of the second sprocket 32. Therefore, as for the behavior when the indenter 21 is separated, the above-mentioned press unit 20 is separated more gently. preferable.

In the above-described embodiment, the indenter 21 on which the parallel surface 24 is formed has been described, but the present invention is not particularly limited thereto. For example, a continuous press device 10C provided with a press unit 20C having an indenter 21C which is trapezoidal when viewed from the side may be used. FIG. 8 is a schematic explanatory view showing an example of another continuous press device 10C. The indenter 21C is not formed with a parallel surface 24, and has an attitude control pin 28, which is an attitude control member, on the upper portion of the end surface 26. The inclined surface 25 of the indenter 21C is an isosceles triangle connecting the axial center of the first sprocket 31 or the axial center of the second sprocket 32 and the end of the press surface 22 (see the alternate long and short dash line in the right enlarged view of FIG. 8). It is formed so as to go inside. The press unit 20C includes a guide member 48 having a guide groove for guiding the attitude control pin 28. The indenter 21C has a tall shape and may have a ratio Z / X of more than 1.5 or a ratio Z / X of 2 or less. Also in this press unit 20C, since the upper surface 27 of the indenter 21C is pressed toward the electrode member 11 by the urging roller 36, it is possible to execute a more appropriate continuous pressing process when increasing the density of the electrode member 11. it can.

In the above-described embodiment, the indenter 21 has been described as having a width X of the press surface 22 satisfying the Lcos θ due to the approach angle θ and the support interval L of the chain 33, but the indenter 21 is pressed by the urging member. If so, it is not particularly limited to those satisfying this. It is preferable that the press surface 22 having the width X of the press surface 22 satisfying Lcos θ is less likely to form a gap between the press surfaces 22.

In the above-described embodiment, the drive unit 34 is arranged on the first sprocket 31 on the upstream side in the transport direction C and is moved by pushing out the indenter 21, but the transport direction C is not particularly limited to this. The drive unit 34 may be arranged on the second sprocket 32 on the downstream side, and the indenter 21 may be moved by pulling. It is preferable to push out the indenter 21 and move it from the viewpoint of making the gap of the press surface 22 zero.

Hereinafter, the results of studies on the press processing of the press apparatus disclosed in the present specification will be described as examples.

The amount of deflection x of the electrode member pressed by the conventional roll press device or the vertical press device was examined. In order to convert the residual stress into strain and make it easier to understand, the experiment was conducted by applying the mixture layer to only one side of the metal current collector, not to both sides. A positive electrode slurry (Li composite oxide) for a general Li battery is applied to one side of an Al current collector foil (thickness 15 μm) and dried, and a negative electrode slurry containing graphite is applied to a Cu current collector foil (thickness 10 μm). ) Was applied to one side to prepare a dried sample. The electrodes coated and dried by changing the basis weight of each mixture layer were pressed to a predetermined density by changing the diameter of the press roll, and the amount of deflection x (mm) of the electrode after punching to a diameter of 20 mm was measured. Table 1 summarizes the basis weight, film thickness, and deflection amount (mm) of the positive electrode and the negative electrode. FIG. 9 is a diagram showing the relationship between the electrode thickness and the amount of deflection after pressing. As shown in Table 1 and FIG. 9, in the roll press, it was found that the larger the coating amount and the thicker the film thickness, or the smaller the diameter of the press roll, the larger the amount of deflection of the electrode. Further, in this measurement result, it was found that the amount of deflection x was larger in the positive electrode than in the negative electrode. Further, it was found that the negative electrode having a large amount of deflection easily causes the interface slip between the current collector foil and the electrode because the interface between the current collector and the mixture layer is peeled off. When the above test is performed with electrodes coated with a mixture layer on both sides of the current collector, the electrodes do not bend because the residual stresses are balanced on the front and back sides, but the internal stress corresponding to the amount of deflection of the single-sided coating is the electrode. It can be said that it remains inside. If the residual stress is larger than a certain level, it is expected that the electrodes will crack or the electrodes will be cut due to some expansion and contraction of the electrodes due to charging and discharging after battery assembly, and the durability and safety will decrease. It was. On the other hand, it was found that the vertical press has a small amount of deflection and less defects such as peeling. Therefore, it has been found that a vertical press is more preferable when manufacturing a thicker film electrode member.

Next, the elongation when the electrode member 11 having a thickness of 3 mm is pressed by a conventional roll press and a vertical press is considered. FIG. 10 is a relationship diagram of penetration angle, elongation, stretching vector and roll diameter at the time of roll press conversion, FIG. 10A is a table summarizing each numerical value, and FIG. 10B is a description of roll diameter R, approach angle θ and stretching vector. It is a figure. FIG. 10A is a table summarizing the roll diameter and stretching ratio of the roll press and the stretching ratio of the vertical press when the approach angle θ is changed in the range of 12.58 ° to 3 °. In a roll press having a diameter of 25 cm, the vector ratio in the stretching direction at the approach angle (12.58 °) at the start of pressing was 22.3. Therefore, it was found that the roll press stretched by 22.3% in the transport direction (horizontal direction) by the bottom dead center assuming that there was no slippage. On the other hand, when the vector ratio is calculated assuming that continuous semicircular indenters are continuously operated in a circular orbit with a diameter of 25 cm and pressed at the same approach angle of 12.58 °, the horizontal component of 100 at bottom dead center is It was 97.6 at the start of the press, and it was found that it increased by 2.4% to the bottom dead center. That is, it was found that in the vertical press, the horizontal stretching was suppressed to about 1/10 of the roll press in the same trajectory. Further, the draw ratio of the roll press was 5.2% even when the roll diameter R was increased to an unrealistic 440 cm, which was reduced to only about 1/4 of the case where the roll diameter was 25 cm. On the other hand, it was found that the draw ratio of the continuous vertical press was drastically reduced to 0.38% when the approach angle was 5 °, and could be reduced to about 1/60 when the roll diameter R was 25 cm. As described above, it was found that the vertical press originally has a feature of low stretching ratio, and the approach angle θ can be reduced without increasing the size of the apparatus, so that an extremely low stretching ratio can be achieved.

(Experimental Examples 1 and 2)
From the above results, a continuous press device 10 provided with a continuous vertical press mechanism was designed (FIGS. 1 to 5). The approach angle θ = 5 °, and the chain support interval L was 12.7 mm. The width X of this indenter was 12.7 mm × cos (5 °) ≈ 12.65 mm. The diameter D of the roller shaft of the urging roller was 80 mm. It was confirmed that in this continuous press device, adjacent indenters can maintain vertical postures while moving to the bottom dead center of the press without a gap. Further, as a reference example, a continuous press device having a structure not provided with an urging roller was manufactured. This continuous press device has a configuration including one press unit 20B of the continuous press device 10B shown in FIG. 7, and does not include an urging roller 36 on the second shaft 42. Using these two devices, the negative electrode of the lithium battery to be pressed and the pressure-sensitive paper were pressed, and the press characteristics were evaluated. The width of the pressed body was 5 cm. The continuous pressing device 10 shown in FIG. 1 was designated as Experimental Example 1, and the continuous pressing device of Reference Example was designated as Experimental Example 2. 11A and 11B are explanatory views showing the support moving portions 30 and 30D of Experimental Examples 1 and 2, FIG. 11A shows Experimental Example 1 having the support moving portion 30 having the urging roller 36, and FIG. 11B shows the urging roller 36. It is explanatory drawing of the experimental example 2 provided with the support moving part 30D which omitted.

(Evaluation)
The press continuity was evaluated by the presence or absence of an unpressed region between the indenters in the pressed body after pressing. The maximum load value was obtained from the degree of discoloration of the pressure-sensitive paper based on a discolored specimen prepared by separately pressing the pressure-sensitive paper with a known load. The maximum load was obtained as a load value occupying the widest area of the pressure-sensitive paper. The load variation on the press surface was determined as the area ratio of the region exceeding the load range of 10% with respect to the load of the widest region by determining the region area of the pressure distribution from the difference in discoloration of each portion.

(Results and discussion)
The evaluation results are summarized in Table 2. As shown in Table 2, in Experimental Example 2, the continuity of the press was good, but it was difficult to increase the maximum load by pressing the indenter with the sprocket, and the press was particularly bent due to the indenter bending. The load variation on the surface was large. On the other hand, in Experimental Example 1 having the urging roller 36, it was found that the continuity of the press was good, there was almost no load variation on the press surface, and an extremely large maximum load could be obtained. In particular, if the indenter length Y becomes longer, it is expected that the deflection of the indenter also increases. Therefore, in a press unit having a large length Y, by adopting an urging roller, a more appropriate continuous pressing process can be performed. It was speculated that it could be done.

The material, shape, processing tolerance, motor type, etc. of each part may be optimally selected according to the desired press pressure, electrode density, and the like. Further, each configuration is not particularly limited to the above size, and a desired size may be selected according to the electrode member. The support shaft of the indenter is preferably an oil-free shaft, but it may be an oil seal shaft. Further, although not shown, a brush for cleaning the indenter press surface after pressing, a vacuum cleaner, or the like may be provided.

It should be noted that the present disclosure is not limited to the above-described examples, and it goes without saying that the present disclosure can be carried out in various aspects as long as it belongs to the technical scope of the present disclosure.

The press devices disclosed herein can be used in the field of manufacturing power storage devices.

10,10B, 10C continuous press device, 11 electrode member, 12 current collector, 13 mixture layer, 15 base, 18 main body, 20,20B, 20C press unit, 21,21B, 21C indenter, 22 press surface, 23 Support shaft, 24 parallel surface, 25 inclined surface, 26 end surface, 27 top surface, 28 attitude control pin, 30, 30D support moving part, 31 first sprocket, 32 second sprocket, 33 chain, 34 drive part, 35 support sprocket, 36 urging roller, 37 pressure surface, 41 1st axis, 42 2nd axis, 45 3rd axis, 46 roller axis, 48 guide member, A press area, C transport direction, D diameter, L support interval, R roll diameter , X width, Y, W length, Z height, θ approach angle.

Claims (11)

A press device that continuously presses while transporting electrode members in the transport direction.
An indenter having a flat press surface in contact with the electrode member,
A support moving portion that arranges and supports a plurality of the indenters and continuously moves the indenters in the transport direction in a predetermined press region that presses the electrode member on the press surface.
An urging member that urges the indenter toward the electrode member in the press region, and
Press equipment equipped with. The pressing device according to claim 1, wherein the urging member is an urging roller that is pivotally supported above the bottom dead center of the indenter in the pressing region and abuts on the indenter. The press device according to claim 2, wherein the urging roller is pivotally supported by a roller shaft having a diameter D larger than the width X of the indenter. In the urging roller, the ratio W / Y of the length Y of the indenter in the direction orthogonal to the transport direction and the length W of the pressure surface that applies a load to the indenter in the direction orthogonal to the transport direction is 0. The press device according to claim 2 or 3, which is in the range of 5 or more and 1 or less. The support moving portion rotates the first sprocket, the second sprocket, the chain that supports the support shaft arranged on the indenter and is hung on the first sprocket and the second sprocket, and the first sprocket. The press device according to any one of claims 1 to 4, further comprising a driving unit for driving. The press area lies between the first sprocket and the second sprocket.
The press device according to claim 5, wherein the urging member is arranged between the first sprocket and the second sprocket. The press device according to claim 5 or 6.
A press device including a support sprocket disposed between the first sprocket and the second sprocket to support the chain. The support moving portion moves the indenter in a range where the approach angle θ, which is the angle formed by the trajectory connecting the center of the press surface and the transport surface of the electrode member in the press region, is 0 ° <θ≤10 °. The press device according to any one of claims 1 to 7. The press device according to any one of claims 1 to 8, wherein the indenter has an upper surface having a convex center when viewed from the side. The press device according to any one of claims 1 to 9, wherein the indenter has a ratio Z / X of the width X and the height Z of the press surface in the range of 1 or more and 2.0 or less. The press device according to any one of claims 1 to 10, wherein a press unit including the indenter, the support moving portion, and the urging member is arranged so as to face each other.