WO2015033511A1 - Apparatus for producing electrode and method for producing electrode - Google Patents

Abstract

Provided are an apparatus and a method for producing an electrode, which provide an electrode with a recess without damaging or deforming the electrode. One embodiment of this apparatus for producing an electrode is provided with a pair of press parts (1) each having a projection (12). Each press main body (11) is provided with the projection (12) such that when the pair of the press parts (1) sandwich an electrode (3), the projections (12) of the press parts (1) face each other with the electrode therebetween. This apparatus for producing an electrode is configured such that the pair of the press parts (1) provides the electrode (3) with recesses (33) by sandwiching the electrode (3). Consequently, the recesses (33) are mechanically formed by the projections (12), thereby suppressing damage to and deformation of the electrode (3).

Description

Electrode manufacturing apparatus and electrode manufacturing method

The present invention relates to an apparatus and method for manufacturing a lithium ion secondary battery, for example, an electrode manufacturing apparatus and method for forming a recess in an electrode.

Lithium ion secondary batteries have been improved to increase energy density. For example, the energy density can be improved by increasing the thickness and density of the electrode layer. On the other hand, since the film thickness increases and the voids decrease, the lithium ion conductivity decreases. At this time, if the electrolyte is sufficiently retained in the electrode, the conduction of lithium ions is not inhibited. For example, when a minute recess is provided on the electrode surface, the electrolyte can be retained, and thus lithium ion conductivity can be improved.
As a method of providing a fine recess on the electrode surface, for example, there is a process of forming a recess in the electrode by laser or etching, a process of pressing the electrode with a roller having a protrusion, and forming a recess in the electrode.
For example, in Patent Document 1, the surface of the active material layer of at least one of the positive electrode and the negative electrode is pressed with a pair of rollers interspersed with a plurality of convex portions, so that the plurality of concave and convex portions are electrode surfaces. Are disclosed.

JP 2013-073812 A

However, in the processing by laser or etching, there is a problem in that the particles of the electrode are damaged by heat or chemical reaction during the processing of forming the recesses. In press working, there is a problem in that the density around the recesses is not uniform, the particles rise due to the non-linear pressure, and the electrodes are deformed. For example, as in Patent Document 1, when the convex portion provided on one side of the roller press is disposed so as not to correspond to the convex portion provided on the other side, the electrode is used when processing a thin electrode. May be deformed.

The present invention has been made in view of such circumstances, and provides an electrode manufacturing apparatus and method for forming a recess without damaging or deforming the electrode.

One aspect of the electrode manufacturing apparatus according to the present invention includes a pair of press portions having convex portions. When the pair of press portions sandwich the electrodes, the convex portions of the press portions are configured to face each other with the electrodes interposed therebetween. In the electrode manufacturing apparatus, the pair of press portions sandwich the electrode to form a recess. Thereby, a convex part forms a recessed part mechanically and physically, and suppresses a damage and a deformation | transformation to an electrode.

In one aspect of the electrode manufacturing apparatus according to the present invention, it is preferable that the convex portion is provided in each press portion so that a linear pressure becomes constant when the press portion sandwiches the electrode. Further, when the pair of press parts sandwich the electrode, the convex part of one press part and the convex part of the other press part are arranged on a straight line. preferable. In other words, when the pair of press parts sandwich the electrode, the convex part of one press part and the other press part are preferably arranged so as to press the same position on the front and back of the electrode. . Alternatively, it is preferable that the gap between the electrode and the convex portion is not generated when the pair of press portions sandwich the electrode.

In one aspect of the electrode manufacturing apparatus according to the present invention, the pair of press sections is preferably a pair of rollers or a flat plate press.

Moreover, one aspect of the electrode manufacturing method according to the present invention is an electrode manufacturing method using an electrode manufacturing apparatus including a pair of press portions having convex portions, wherein the pair of press portions is a convex portion included in each press portion. The electrode is sandwiched so as to face each other, and the convex portion forms a concave portion in the electrode.

In one aspect of the electrode manufacturing method according to the present invention, when a pair of press parts sandwich the electrode, the convex part of one press part and the convex part of the other press part are in a straight line. It is preferable that the pair of press portions sandwich both sides of the electrode so as to be disposed. It is preferable that the pair of press portions sandwich the electrode so that a gap between the electrode and the convex portion does not occur.

According to one embodiment of the electrode manufacturing apparatus according to the present invention, the recess can be formed without damaging or deforming the electrode.

It is a figure explaining the outline of the process in which the electrode manufacturing apparatus which concerns on Embodiment 1 manufactures an electrode. It is a figure explaining a state when the press part of the electrode manufacturing apparatus of Embodiment 1 presses an electrode. It is a figure explaining the problem of the recessed part formation by a laser or an etching. It is a photograph which shows an example of the recessed part formed by the method of FIG. It is a figure explaining the problem of patent document 1. FIG. It is a figure which shows an example of the electrode manufacturing apparatus comprised by a pair of roll. 2 is a front view of a recess of Comparative Example 1. 4 is a cross-sectional photograph of the periphery of a recess in Comparative Example 1. 3 is a front view of a recess of Example 2. FIG. 4 is a cross-sectional photograph of the periphery of a recess according to Example 2.

Hereinafter, embodiments will be described with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, components having the same configuration or function and corresponding parts are denoted by the same reference numerals and description thereof is omitted.

The electrode manufacturing apparatus of one embodiment has at least a pair of press portions provided with convex portions, and is provided so that the convex portions of the press portions face each other. And a pair of press part is comprised so that an electrode may be pressed and a recessed part (concave shape, a hole, a dent) may be formed.
Hereinafter, aspects of each embodiment will be described with reference to the drawings.

FIG. 1 is a diagram illustrating an outline of a process in which an electrode manufacturing apparatus according to Embodiment 1 manufactures an electrode. The press part 1 which an electrode manufacturing apparatus has has the press main body 11 and the convex part 12. FIG. The convex portions 12 arranged in the press body 11 can adopt a staggered arrangement in the conveying direction or a lattice arrangement at a predetermined pitch. Moreover, the convex part 12 should just form a convex shape on the surface of the press main body 11. For example, the shape of the convex portion 12 is various, such as a shape raised from the surface of the press body such as a kamaboko shape, a rectangular parallelepiped, a cylinder, a prism, or a shape with a sharp tip such as a cone, a quadrangular pyramid, a polygonal pyramid, etc. It can be formed by a simple polyhedron.

FIG. 1 shows a process in which the pressing unit 1 of the electrode manufacturing apparatus presses the electrode 3. The electrode 3 has an electrode mixture layer 32 (active material layer) on both sides of a current collector foil 31 (current collector). The electrode mixture layer 32 is made of a battery material containing a positive or negative electrode active material, a binder, a conductive additive, and the like, and is applied to both surfaces of the current collector foil 31.
With reference to FIG. 1, the outline of the press process which the press part 1 implements is demonstrated. The press part 1 is arrange | positioned at the both sides of the electrode 3 (left figure of FIG. 1). When the pressing part 1 sandwiches the electrode 3, the convex part 12 is pressed into the electrode mixture layer 32 and presses the electrode 3 (center view in FIG. 1). When the pressing of the electrode 3 by the pressing unit 1 is completed, the electrode 3 is pressed, the density is adjusted, and the recess 33 is formed in the electrode mixture layer 32 (recess formation, hole processing).

In this embodiment, when the press part 1 presses the electrode 3, the some convex part 12 which each press part 1 has is provided so that it may oppose on both sides of the electrode 3. As shown in FIG. In other words, each press part 1 is provided so that each convex part 12 may oppose the same position of the front and back (both surfaces) of the electrode 3. Accordingly, when the pair of press portions 1 sandwich the electrode 3, the convex portions 12 are arranged on a straight line, and pressure is applied to the same position from the front and back of the electrode. FIG. 2 schematically shows a state when the pressing unit 1 presses the electrode 3. The direction indicated by the black arrow at the tip of each convex portion 12 is the direction in which pressure is applied. Since each convex part 12 is arranged on the straight line with the convex part 12 facing each other, an equal pressure can be applied to the electrode 3.

Next, features of the electrode manufacturing apparatus of Embodiment 1 will be described in detail.
(1) Press part (machining press) having convex parts (micromachining)
The concave portion is mechanically formed by a press apparatus (press portion 1) subjected to fine processing. Specifically, the press part 1 has the convex part 12 formed by fine processing, and processes the electrode 3 mechanically. The convex part 12 has a fine shape, and is finely processed so that, for example, a concave part 33 in the range of 1 μm to 1000 μm can be formed.
When the electrode 3 is sandwiched by the press part 1, the convex part 12 physically pushes the particles of the electrode mixture layer 32. For this reason, the concave portion 33 can be formed without damaging the particles of the battery material due to heat or chemical reaction.

For example, in the conventional technique, as shown in FIG. 3, the electrode mixture layer 32P (left side in FIG. 3) of the electrode 3P is laser-etched or etched to form the recess 33P (right side in FIG. 3). When the concave portion is formed by such a technique, a thermal reaction or a chemical reaction is caused to the particles of the electrode mixture layer 32P to cause damage. FIG. 4 shows a scanning electron micrograph (SEM) of the electrode surface when the recesses are formed by laser or etching. FIG. 4 shows an example of a photograph around the recess 33P formed by the method shown in FIG. As shown in FIG. 4, damage is given to the particles around the processed portion where the recess 33 </ b> P is formed. In FIG. 4, a portion indicated by a white arrow is the periphery of the processed portion of the recess.

(2) Density adjustment by constant linear pressure and formation of concave portion Density adjustment (pressing) and concave portion of electrode 3 with respect to electrode 3 after drying by press portion 1 subjected to fine processing so that the press linear pressure becomes constant Simultaneously with formation. The density of the electrode 3 is adjusted by, for example, 1.0 to 4.0 × 10 ³ kg / m ³ (1.0 to 4.0 g / cc) when the press unit 1 sandwiches the electrode 3 and applies pressure. Adjust to. By using the press part 1, the recessed part 33 can be formed (drilling), making the density (hardness) of the electrode mixture layer 32 uniform including the circumference | surroundings which form the recessed part 33. FIG.
A press device that has been subjected to micromachining with a constant linear pressure is, for example, a device in which the distances between all micromachined convex portions 12 are constant (the distances between all microfabricated convex portions are constant). When the distance to the nearest convex part (distance between adjacent convex parts) differs depending on the convex part 12, the press line pressure becomes non-uniform. In addition, when the concave portion is formed with the electrode after density adjustment, the density is not uniform because there are few voids and particles cannot escape. Furthermore, if the press line pressures on the front and back sides are not constant, density unevenness around the recesses and deformation of the electrode body occur. In addition, since particle escape is possible only in the electrode surface direction, particle swell occurs.

Since the electrode before density adjustment has many voids, particles escape during formation of the recess, and the density locally changes. Since the press part 1 of this embodiment applies a press linear pressure uniformly to the whole electrode (including a recessed part forming part), it can implement recessed part formation, making density uniform.
In addition, the unpressed electrodes are in a soft state, and when the holes are made in the electrodes, the electrodes around the recesses easily escape to the surroundings, making it difficult to make the electrodes dense. Moreover, since the unpressed electrode is soft, the convex part 12 described in the above (1) is easy to physically push the particles of the electrode mixture layer 32. On the other hand, when a hole is made after pressing, there is no escape area for the electrodes around the recesses, the electrodes around the recesses are dense, and the electrodes between adjacent recesses are sparse.
In the present embodiment, density adjustment and recess formation are performed with a constant linear pressure, thereby suppressing uneven density around the recess. Also, electrode deformation due to non-uniform linear pressure is suppressed.

Regarding the deformation of the electrode due to non-uniform linear pressure, for example, as in the technique of Patent Document 1, when using a roll-type press device in which the convex portion of one roller and the convex portion of the other roller are not opposed to each other Will be described with reference to FIG. FIG. 5 schematically shows a cross-sectional shape of the electrode when the recess is formed on the thin electrode by the technique of Patent Document 1. The pressure from the convex part of one roller and the pressure from the convex part of the other roller are applied to different positions without being applied linearly to the electrode 3P. The direction and position where the pressure from the convex portion is applied are indicated by black arrows. As shown in FIG. 5, the line pressure on the surface of the electrode 3P and the front and back of the electrode 3P becomes non-uniform, and the density around the recess 33P becomes non-uniform. Further, due to the non-uniform linear pressure, swell of particles, deformation of the electrode 3P, and deformation of the current collecting foil 31P of the electrode occur.

(3) The clearance distance between the press device and the electrode is zero, and the front and back line pressure is constant. The clearance distance (gap) between the press part 1 and the electrode 3 is set to zero, and the press part 1 and the electrode 3 are processed in close contact. . And the convex part 12 is arrange | positioned so that the press linear pressure of front and back may become fixed when it sees in an electrode cross section. In order to make the press linear pressure on the front and back constant, the arrangement of the convex portions 12 provided on the press portion 1 is adjusted so that a uniform pressure is applied to the front and back of the electrode 3. For example, the convex part 12 of the press part 1 that sandwiches the electrode 3 from the front and back of the electrode 3 (hereinafter referred to as “the convex part 12 of the press part 1 that sandwiches the electrode 3 from the front and back of the electrode 3” is appropriately referred to as “the convex part of the front and back sides”. 12 ”). Thereby, the press line pressure does not escape, and the escape of the particles of the electrode mixture layer 32 around the recess 33 and the deformation of the current collector foil 31 can be suppressed. When density adjustment and recess formation are performed with clearance, particles escape in the direction of the electrode surface, and the surface of the recess 33 rises. Moreover, when the linear pressure by the convex parts 12 on the front and back sides is not constant, the electrode 3 is deformed in the thickness direction of the electrode 3.
In the present embodiment, the clearance distance between the pressing device and the electrode is made zero, and the pressing linear pressure on the front and back surfaces is made constant, so that the particle swell of the electrode mixture layer 32 and the electrode 3 (current collection) The deformation of the foil 31) is suppressed.

As described above, in the electrode manufacturing apparatus according to the present embodiment, the pressed part 1 (pressing apparatus) has the above-described features (1) to (3), so that the particles of the electrode mixture layer 32 generated when the recess is formed. Therefore, it is possible to realize damage prevention, uniform density around the recesses, and suppression of swell of the electrode mixture layer 32 and deformation of the electrode. These are remarkable as advantageous effects when drilling holes of 1 μm or more and less than 1000 μm.
In addition, in this embodiment, the convex part 12 is provided in the press main body 11 by the size of 1 micrometer to 1000 micrometers by fine processing. For example, the thickness of the electrode for automobiles is generally 1000 μm or less and substantially one side of 200 μm (one side thickness of the electrode mixture layer 32). For example, since the convex part of Patent Document 1 is pressed at a pitch of 1 μm to 10 μm, the effect of cell performance does not occur. On the other hand, in this embodiment, since the micro-processed convex part 12 is used, it is useful for improving cell performance.

Embodiment 2. FIG.
An aspect in which the press unit 1 according to the first embodiment is applied to an apparatus (roller type pressing apparatus) that employs a roller type pressing method will be described. FIG. 6 shows an example of an electrode manufacturing apparatus when the press unit 1 of Embodiment 1 is applied to a roller-type pressing method. FIG. 6 shows an example in which the press unit 1 is realized by a roller (roll type press, press roller). In FIG. 6, the figure which looked at the pair of roller 5 which comprises the press part 1 from the side is shown. Each roller 5 includes a roller main body 51 and a convex portion 52. The convex portions 52 are arranged so as to face each other when the pair of rollers 5 sandwich the electrode 3. In the example of FIG. 5, the electrode 3 is conveyed from the right side to the left side and is sandwiched between a pair of rollers 5, and density adjustment and recess formation are performed. In FIG. 6, means other than the pair of rollers 5 constituting the press unit 1 such as means for conveying the electrodes are omitted. In addition, the convex portion 52 provided in the roller 5 is schematically shown, and more fine convex portions 52 are actually arranged.

Moreover, the press part 1 of Embodiment 1 is applicable also to the apparatus (flat plate press apparatus) which employ | adopts the flat plate press method. In this case, the press part 1 is comprised by a pair of flat plate press. The pair of flat plate presses have convex portions 12 as shown in FIG.
When the electrode 3 is pressed by the roller-type pressing method or the flat plate pressing method, the surface of the pressed electrode 3 becomes a shape in which fine holes are formed in a film shape.

The effects described in the first embodiment can also be achieved when the press unit 1 of the first embodiment is applied to a roll-type press method and a flat plate press apparatus.

[Example]
In both Examples 1 and 2 and Comparative Example 1, the positive electrode and the negative electrode shown in the experimental conditions were used. In addition, density adjustment and hole processing (recess formation) were performed by the roll-type pressing method in Example 1 and the flat plate pressing method in Example 2. In Comparative Example 1, the density adjustment was performed by a roll-type pressing method, and the recess formation was performed by a separate method from the flat plate pressing method. Details are shown for each of Examples and Comparative Examples in the items of drilling and density adjustment.

Experimental conditions:
Positive electrode:
Active material: ternary positive electrode active material Binder: Polyvinylidene fluoride (PVdF)
Conductive aid: Acetylene black (AB)
Aluminum foil thickness: 15μm
Electrode thickness: 200 μm (92.5 μm on one side)
Density: Adjusted from 1.8 × 10 ³ kg / m ³ to 2.8 × 10 ³ kg / m ³ (1.8 → 2.8 g / cc)
Processing line pressure: 500 kN / cm
Negative electrode:
Active material: Natural graphite Binder: Styrene butadiene rubber (SBR)
Conductive aid: Acetylene black (AB)
Copper foil thickness: 10 μm
Electrode thickness: 300 μm (one side 145 μm)
Density: Adjusted from 1.1 × 10 ³ to 1.3 × 10 ³ kg / m ³ (1.1 → 1.3 g / cc)
Processing line pressure: 500 kN / cm

Drilling and density adjustment:
[Example 1]
Roll type press machine Press part: Φ100 mm roll type press Convex part shape: 200 μm square, quadrangular pyramidal convex part Convex part spacing: 200 μm pitch, staggered in the conveying direction Convex part depth: 50 μm
Clearance :: 0mm
Convex part arrangement: same on both sides [Example 2]
Flat plate press device Press part: 90mm Flat plate press Convex part shape: Φ40μm, conical convex part (tilt of tip part 30 degrees)
Convex part arrangement interval: 100 μm pitch, staggered arrangement Convex part depth: 50 μm
Clearance :: 0mm
Convex part arrangement: same on both sides [Comparative Example 1]
Roll type press device and flat plate press device Density adjustment press part: Φ200 mm roll type press Hole processing press part: 90 mm flat plate press Convex part shape: Φ40 μm, conical convex part (tilt of tip part 30 degrees)
Protrusion arrangement interval: Vertical 800 μm pitch, horizontal 800 pitch, lattice arrangement Protrusion depth: 50 μm
Clearance: 1mm
Convex part arrangement: Arrangement with different front and back convex parts

Test results:
7 to 10 show electron micrographs of the recesses formed in Comparative Example 1 and Example 2. FIG. As shown in FIG. 7, the shape of the recess formed by Comparative Example 1 showed a state in which particles were raised on the surface of the recess. Further, as shown in FIG. 8, the density of the cross section around the concave portion is high and low. Further, the current collector foil is deformed.
As shown in FIG. 9, the shape of the recess formed in Example 2 does not cause a phenomenon that particles rise on the surface of the recess. Also, as shown in FIG. 10, the cross section around the recess has a uniform density and no density. In addition, the current collector foil is not deformed.
In Example 1, the same results as in Example 2 were observed.

It should be noted that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

This application claims priority based on Japanese Patent Application No. 2013-185923 filed on September 9, 2013, the entire disclosure of which is incorporated herein.

DESCRIPTION OF SYMBOLS 1 Press part 11 Press main body 12 Convex part 3, 3P Electrode 31, 31P Current collection foil 32, 32P Electrode compound layer 33, 33P Concave part

Claims (10)

1. Provided with a pair of press parts having convex parts,
   An electrode manufacturing apparatus configured such that, when the pair of press portions sandwich an electrode, the convex portions of each press portion face each other with the electrode interposed therebetween.
2. 2. The electrode manufacturing apparatus according to claim 1, wherein the convex portion is provided in each press portion so that a linear pressure becomes constant when the press portion sandwiches the electrode.
3. 2. The configuration is such that when the pair of press parts sandwich the electrode, the convex part of one press part and the convex part of the other press part are arranged on a straight line. Or the electrode manufacturing apparatus of 2.
4. When the pair of press parts sandwich the electrode, the convex part of one press part and the other press part are arranged to press the same position on the front and back of the electrode. The electrode manufacturing apparatus according to claim 1 or 2.
5. The electrode manufacturing apparatus according to any one of claims 1 to 4, wherein a gap between the electrode and the convex portion is not generated when the pair of press portions sandwich the electrode. .
6. The electrode manufacturing apparatus according to any one of claims 1 to 5, wherein the pair of press portions is a pair of rollers.
7. The electrode manufacturing apparatus according to any one of claims 1 to 5, wherein the pair of press portions is a pair of flat plate presses.
8. An electrode manufacturing method using an electrode manufacturing apparatus comprising a pair of press portions having convex portions,
   The pair of press portions sandwich the electrodes so that the convex portions of each press portion face each other,
   An electrode manufacturing method in which the convex portion forms a concave portion in the electrode.
9. The electrode manufacturing method according to claim 8, wherein the pair of press parts sandwich both sides of the electrode so that the convex part of one press part and the convex part of the other press part are arranged on a straight line. .
10. The electrode manufacturing method according to claim 8 or 9, wherein the pair of press portions sandwich the electrode so that a gap between the electrode and the convex portion does not occur.

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