Patent Description:
In general, a secondary battery includes a positive electrode and a negative electrode, each of which includes a current collector having an active material applied to one surface or opposite surfaces thereof, and a separator. An electrode, such as a positive electrode or a negative electrode, is formed by manufacturing an electrode sheet having an electrode active material applied to one surface or opposite surfaces thereof and cutting the manufactured electrode sheet.

<FIG> is a schematic view showing a conventional electrode sheet cutting apparatus and method, and <FIG> is an enlarged view showing the section of an electrode sheet cut by the conventional electrode sheet cutting apparatus.

In the conventional electrode sheet cutting apparatus, as shown in <FIG>, (i) an electrode sheet <NUM> is disposed on an electrode sheet support <NUM> having a recess formed at a portion at which an electrode sheet section is provided, and (ii) the electrode sheet <NUM> is cut using a cutter <NUM>. At this time, the cutter <NUM> applies force to the recess in the electrode sheet support <NUM> to cut the electrode sheet <NUM>. In the case in which no recess is provided in the electrode sheet support <NUM>, the cutter <NUM> applies force above the section of the electrode sheet <NUM> to cut the electrode sheet <NUM>.

In the conventional electrode sheet cutting apparatus, however, an electrode section <NUM> may be deformed or a residue, such as burr, is present at the electrode section <NUM> when the electrode sheet <NUM> is cut, as shown in <FIG>.

In the case in which a portion of the electrode sheet <NUM> is deformed or a residue, such as burr, is present, as shown in <FIG>, transfer of the electrode sheet <NUM> may be impeded by the deformed portion or the residue, and when an electrode assembly is formed, density of the electrode assembly is reduced by the deformed portion or the residue, whereby capacity of a battery is reduced. Also, in the case in which a pouch-shaped secondary battery is formed using electrodes, the electrodes may not be stably stacked, whereby it may not be possible to form the battery so as to have a desired shape.

In the drawings of Patent Document <NUM>, cutters configured to cut an electrode plate are located at opposite surfaces of a target. However, cutting is performed from the middle part of the target, and therefore removal of a residue and deformation of the cut surface of an electrode sheet are not considered.

Therefore, an electrode sheet cutting apparatus capable of minimizing a residue due to electrode cutting while minimizing deformation of an electrode sheet at the time of cutting the electrode sheet and an electrode sheet cutting method using the same are required.

<CIT>, upon which the preamble of claim <NUM> is based, discloses a sheet cutting apparatus comprising an upper cutter configured to be located above a sheet, the upper cutter being configured to cut the sheet; a lower cutter located so as to correspond to the upper cutter, the lower cutter being configured to engage the upper cutter so as to cut the sheet; and an sheet support located between the upper cutter and the lower cutter, the sheet support being configured to support the sheet and having a passage in which the lower cutting blade can move vertically.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an electrode sheet cutting apparatus capable of minimizing deformation of an electrode sheet and an electrode sheet cutting method using the same.

It is another object of the present invention to provide an electrode sheet cutting method capable of minimizing deformation and residue of an electrode sheet due to cutting of the electrode sheet by defining the cutting position and sequence of the electrode sheet.

In order to accomplish the above objects, an electrode sheet cutting apparatus according to the present invention is defined in the appended set of claims, and includes an upper cutter configured to be located above an electrode sheet, the upper cutter being configured to cut the electrode sheet; a lower cutter located so as to correspond to the upper cutter, the lower cutter being configured to engage the upper cutter so as to cut the electrode sheet; and an electrode sheet support located between the upper cutter and the lower cutter, the electrode sheet support being configured to support the electrode sheet, the electrode sheet support being provided with a through hole configured to correspond to a cutting portion of the electrode sheet being cut at which the upper cutter and the lower cutter are configured to engage each other.

Also, the upper cutter and the lower cutter may be each configured to apply an identical force to the electrode sheet.

Also, the upper cutter and the lower cutter may be each configured to move to the electrode sheet at an identical speed.

Also, the upper cutter and the lower cutter are each configured to cut the electrode sheet while widening a cutting range of the electrode sheet from one side of the cutting portion.

Also, the cutting portion may be widened from a portion adjacent to a middle part of the electrode sheet to a contoured portion of the electrode sheet.

The upper cutter and the lower cutter may each have a symmetrical shape to one another.

The distance between the upper cutter and the lower cutter before the electrode sheet is cut may gradually increase toward one side.

The electrode sheet may be cut to form an electrode tab protrusion.

At this time, the upper cutter and the lower cutter may be configured to start cutting the electrode sheet at a position at which the electrode tab protrusion is to be formed.

In addition, the present invention provides an electrode sheet cutting method including (S1) disposing an electrode sheet on an electrode sheet support having a through hole formed at a portion at which the electrode sheet is to be cut; and (S2) cutting the electrode sheet using an upper cutter and a lower cutter according to any one of claims <NUM> to <NUM>.

In step (S2), the electrode sheet may be cut in a longitudinal direction or a direction perpendicular thereto to form a single electrode assembly or may be cut in a concave-convex shape to form an electrode tab.

When the electrode tab is formed in step (S2), the upper cutter and the lower cutter may first cut a protrusion of the electrode tab and may then cut a place on the electrode sheet farthest from the protrusion of the electrode tab in step (S2).

The place on the electrode sheet farthest from the protrusion of the electrode tab may be another cutting portion of the electrode sheet.

In the present invention, one or more constructions that do not conflict with each other may be selected and combined from among the above constructions.

Hereinafter, an electrode sheet cutting apparatus according to the present invention and an electrode sheet cutting method using the same will be described in detail with reference to the accompanying drawings.

<FIG> is a schematic view showing an electrode sheet cutting apparatus and method according to the present invention.

The electrode sheet cutting apparatus according to the present invention includes an electrode sheet support <NUM> configured to support an electrode sheet <NUM>, an upper cutter <NUM> located above the electrode sheet <NUM>, and a lower cutter <NUM> located under the electrode sheet support <NUM>, the lower cutter being disposed at the position at which the lower cutter engages the upper cutter <NUM>.

At this time, the electrode sheet support <NUM> may be provided with a through hole <NUM>, which is formed in a cutting portion of the electrode sheet <NUM> being cut at which the upper cutter <NUM> and the lower cutter <NUM> are configured to engage each other, such that the upper cutter <NUM> and the lower cutter <NUM> engage each other while cutting the electrode sheet <NUM>.

The upper cutter <NUM> is connected to an upper pressing portion <NUM>, and the lower cutter <NUM> is connected to a lower pressing portion <NUM> so as to be moved at predetermined force and speed. The upper cutter <NUM> applies upper pressing force F1 above the electrode sheet <NUM>, and the lower cutter <NUM> applies lower pressing force F2 under the electrode sheet <NUM>. The lower cutter <NUM> cuts the electrode sheet <NUM> through the through hole <NUM> and engages the upper cutter <NUM>.

The upper pressing force F1 and the lower pressing force F2 may be equal to each other in order to prevent deformation of the electrode sheet <NUM>. In the case in which the force of the upper cutter <NUM> applied to the electrode sheet <NUM> and the force of the lower cutter <NUM> applied to the electrode sheet <NUM> are equal to each other, a danger of the electrode sheet <NUM> being deformed upwards or downwards is reduced.

In addition, the upper cutter <NUM> and the lower cutter <NUM> may be spaced apart from the electrode sheet <NUM> by the same distance and may reach the electrode sheet at the same speed. As a result, the upper cutter <NUM> or the lower cutter <NUM> may be prevented from early reaching and cutting the electrode sheet <NUM>, whereby it is possible to inhibit deformation of the electrode sheet <NUM>.

<FIG> is a schematic view showing an upper cutter and a lower cutter of an electrode sheet cutting apparatus according to a first embodiment of the present invention, and <FIG> is a schematic view showing another shape of the upper cutter and the lower cutter of the electrode sheet cutting apparatus according to the first embodiment.

In the electrode sheet cutting apparatus according to the first embodiment of the present invention, the upper cutter <NUM> and the lower cutter <NUM> may have the same shape. When viewed from the side, each of the upper cutter <NUM> and the lower cutter <NUM> may have a rectangular shape or a parallelogram shape, as shown in <FIG>, or each of the upper cutter <NUM> and the lower cutter <NUM> may have a right triangular shape in which one side of each of the upper cutter <NUM> and the lower cutter <NUM> protrudes more than the other thereof, as shown in <FIG>. However, the shape of each of the upper cutter and the lower cutter is not restricted as long as it is possible to uniformly cut the electrode sheet <NUM>.

The inter-cutter distance B between the upper cutter <NUM> and the lower cutter <NUM> before the electrode sheet <NUM> is cut may gradually increase from one end to the other end thereof, as shown in <FIG>. That is, the distance at which the upper cutter <NUM> and the lower cutter <NUM> engage each other first may be very short, and the inter-cutter distance B may gradually increase in a cutting direction A.

The upper cutter <NUM> and the lower cutter <NUM> disposed as described above may cut the electrode sheet <NUM> while extending a cutting range from one side of the cutting portion. That is, the upper cutter <NUM> and the lower cutter <NUM> may be operated like a fodder chopper. As a result, a movement range of each of the upper cutter <NUM> and the lower cutter <NUM> at one corner of the cutting portion and a movement range of each of the upper cutter and the lower cutter at the other corner of the cutting portion may be different from each other.

In the case in which the electrode sheet cutting apparatus according to the present invention performs cutting while extending a range from one side to the other side of the cutting portion, as described above, force applied to the electrode sheet is increased, whereby cutting is easily performed, and deformation of the electrode sheet is reduced. In addition, since cutting is performed while extending the range from one side to the other side, foreign matter generated due to cutting moves to the other side.

At this time, in order to easily remove the foreign matter, it is preferable for the cutting portion to be widened from a portion adjacent to a middle part of the electrode sheet <NUM> to a contour portion of the electrode sheet, i.e. it is preferable that the upper cutter <NUM> and the lower cutter <NUM> engage each other first at the middle part of the electrode sheet <NUM> and then the cutting portion be widened to the contour portion of the electrode sheet <NUM>.

In the electrode sheet cutting apparatus according to the present invention, after the electrode sheet is cut as the result of being operated like the fodder chopper, the inter-cutter distance B decreases until the entire surfaces of the upper cutter <NUM> and the lower cutter <NUM> engage each other, as shown in <FIG>. Subsequently, the entire surfaces of the upper cutter <NUM> and the lower cutter <NUM> engage each other to cut the cutting portion, and then the upper cutter <NUM> and the lower cutter <NUM> move so as to become distant from the electrode sheet <NUM>.

That is, an electrode sheet cutting method according to the present invention may mainly include steps of: (S1) disposing an electrode sheet <NUM> on an electrode sheet support <NUM> having a through hole <NUM> formed at a portion at which the electrode sheet <NUM> is to be cut and (S2) cutting the electrode sheet <NUM> using an upper cutter <NUM> and a lower cutter <NUM>. After step (S2), a step of removing the upper cutter <NUM> and the lower cutter <NUM> from the electrode sheet <NUM> after cutting of the electrode sheet <NUM> is completed may be performed.

<FIG> is a schematic view showing an upper cutter and a lower cutter of an electrode sheet cutting apparatus according to a second embodiment of the present invention.

The upper cutter <NUM> and the lower cutter <NUM> of the electrode sheet cutting apparatus according to the second embodiment of the present invention may be disposed in a symmetrical fashion, whereby the inter-cutter distance may be the shortest at one corner of each of the upper cutter <NUM> and the lower cutter <NUM> and the inter-cutter distance may be the longest at the other corner of each of the upper cutter and the lower cutter. That is, the upper cutter <NUM> and the lower cutter <NUM> may be disposed in a symmetrical fashion while each of the upper cutter and the lower cutter has a right triangular shape.

After the upper cutter <NUM> and the lower cutter <NUM> come into contact with the electrode sheet <NUM> first at one corner of each thereof, the shape or position of the upper cutter <NUM> and the lower cutter <NUM> may be changed.

As an example, the angle of the upper cutter <NUM> may be changed while the upper cutter <NUM> enters the upper pressing portion <NUM>, to which the upper cutter <NUM> is connected, and the angle of the lower cutter <NUM> may also be changed so as to correspond to the upper cutter <NUM> while the lower cutter <NUM> enters the lower pressing portion <NUM>, to which the lower cutter <NUM> is connected. Finally, edges of the upper cutter <NUM> and the lower cutter <NUM> may come into complete contact with each other, as shown in <FIG>.

<FIG> is a schematic view showing the upper part of an electrode sheet support according to the present invention.

The electrode sheet support <NUM> according to the present invention is provided with a through hole <NUM> corresponding to a cutting portion at which an electrode sheet is cut, as shown in <FIG>. The through hole <NUM> is an empty hole configured to allow the lower cutter <NUM> to extend therethrough. The size of the through hole <NUM> is set in consideration of the radius of the lower cutter <NUM> due to movement or change in angle thereof. At this time, in order to prevent damage to the lower cutter <NUM> due to movement or change in angle thereof, an electrode sheet damage prevention portion may be provided in the through hole <NUM>. It is preferable for the electrode sheet damage prevention portion to be made of a flexible material in order to protect the electrode sheet while not damaging the edge of the lower cutter <NUM>.

<FIG> is an enlarged view showing the section of an electrode sheet cut by the electrode sheet cutting apparatus according to the present invention.

An electrode section <NUM> according to the present invention means the point of the electrode sheet <NUM> at which the upper cutter and the lower cutter engage each other, i.e. the point of the electrode sheet at which the electrode sheet is cut, as shown in <FIG>.

The electrode section <NUM> may be divided into an electrode tab section and an electrode sheet section depending on the portion that is cut. The cutting sequence or cutting start region of the electrode sheet <NUM> may be changed depending on the kind of the electrode section <NUM>.

<FIG> is a schematic view showing the electrode sheet cutting apparatus according to the present invention and an electrode sheet cut thereby.

As shown in (i) of <FIG>, in order to obtain a plurality of electrode tab portions <NUM> from a single electrode sheet <NUM>, the single electrode sheet <NUM> may be cut to form the plurality of electrode tab portions <NUM>.

In the case in which the electrode sheet <NUM> is manufactured, as described above, the electrode sheet <NUM> may be cut in a longitudinal direction or a direction perpendicular thereto in order to form a single electrode assembly or may be cut in a concave-convex shape in order to form an electrode tab portion <NUM> in (S2) the step of cutting the electrode sheet <NUM>.

When an electrode tab section <NUM> for electrode tab cutting is formed, it is preferable to perform cutting first in an electrode tab protrusion cutting direction a and then to perform cutting in a direction perpendicular to the protruding direction a of the electrode tab portion <NUM>, i.e. an electrode tab concave cutting direction b, which is a direction toward the electrode sheet <NUM>, in order to minimize deformation of the electrode sheet <NUM> and to easily remove foreign matter generated due to cutting. In addition, it is preferable to first cut the place at which the electrode tab portion <NUM> protrudes, i.e. the place closest to the electrode tab protrusion, and to last cut the place farthest from the electrode tab protrusion in the electrode tab concave cutting direction b. That is, in a left electrode tab concave cutting direction b-<NUM>, which is one of the electrode tab concave cutting direction b, it is preferable to perform cutting from the left side to the right side, since the electrode tab portion <NUM> is formed at the left side of the place at which cutting starts. Also, in a right electrode tab concave cutting direction b-<NUM>, which is the other of the electrode tab concave cutting direction, it is preferable to perform cutting from the right side to the left side, since the electrode tab portion <NUM> is formed at the right side of the place at which cutting starts.

The left electrode tab concave cutting direction b-<NUM> and the right electrode tab concave cutting direction b-<NUM> engage each other at the place farthest from the place at which the electrode tab portion <NUM> is formed, i.e. the center between the electrode tab portions <NUM>. At this region, the electrode sheet <NUM> is cut in a direction perpendicular to the electrode tab concave cutting direction b to form a unit cell electrode for an electrode assembly.

To this end, the electrode sheet cutting apparatus according to the present invention includes an upper cutter <NUM>, an upper pressing portion <NUM>, a lower cutter <NUM>, and a lower pressing portion <NUM>, as shown in (ii) of <FIG>. When the electrode sheet is cut, therefore, the upper cutter <NUM> and the lower cutter <NUM> are deformed.

At this time, it is preferable for the most protruding portions of the upper cutter <NUM> and the lower cutter <NUM> to be disposed at the place closest to the position at which the electrode tab portion <NUM> is to be formed depending on the position of the electrode tab portion <NUM>, and it is preferable for the upper cutter <NUM> and the lower cutter <NUM> to be disposed so as to be most deeply recessed at the electrode sheet section <NUM> cut to form the unit cell electrode.

<FIG> is a view showing the result of virtual simulation of force applied to the electrode sheet by the electrode sheet cutting apparatus.

Force applied to the electrode sheet by the electrode sheet cutting apparatus decreases with increasing contact area between the electrode sheet cutting apparatus and the electrode sheet.

That is, the conventional electrode sheet cutting apparatus uniformly contacts the electrode sheet over the entire area (area = <NUM>), whereby force applied to the electrode sheet decreases (stress = <NUM>), as shown in <FIG>. In contrast, a portion (area < <NUM>) of the electrode sheet cutting apparatus according to the present invention comes into contact with the electrode sheet first, whereby force applied to the electrode sheet increases (stress > <NUM>), as shown in <FIG>. As a result, the electrode sheet is rapidly cut, and deformation of the electrode sheet is reduced.

Although the specific details of the present invention have been described in detail, those skilled in the art will appreciate that the detailed description thereof discloses only preferred embodiments of the present invention and thus does not limit the scope of the present invention. Accordingly, those skilled in the art will appreciate that various changes and modifications are possible, without departing from the category and the technical idea of the present invention, and it will be obvious that such changes and modifications fall within the scope of the appended claims.

An electrode sheet cutting apparatus and an electrode sheet cutting method according to the present invention are capable of minimizing deformation of an electrode sheet. In addition, it is possible to easily remove foreign matter generated due to cutting of the electrode sheet such that an electrode is not affected by the foreign matter.

In addition, it is possible to cut the electrode sheet so as to have a regular shape, whereby it is possible to uniformly stack electrodes, and it is possible to provide a regular shape in the case in which the electrodes are stacked in a pouch-shaped case. Furthermore, the electrodes are stacked at a uniform height, whereby it is possible to improve density and capacity of the electrode.

Claim 1:
An electrode sheet cutting apparatus comprising:
an upper cutter (<NUM>) configured to be located above an electrode sheet, the upper cutter (<NUM>) being configured to cut the electrode sheet (<NUM>);
a lower cutter (<NUM>) located so as to correspond to the upper cutter (<NUM>), the lower cutter being configured to engage the upper cutter (<NUM>) so as to cut the electrode sheet (<NUM>); and
an electrode sheet support (<NUM>) located between the upper cutter (<NUM>) and the lower cutter (<NUM>), the electrode sheet (<NUM>) support being configured to support the electrode sheet (<NUM>), characterized in that the electrode sheet (<NUM>) support is provided with a through hole (<NUM>) configured to correspond to a cutting portion of the electrode sheet (<NUM>) being cut at which the upper cutter (<NUM>) and the lower cutter (<NUM>) are configured to engage each other,
wherein an inter-cutter distance (B) between the upper cutter (<NUM>) and the lower cutter (<NUM>) before the electrode sheet (<NUM>) is cut is formed to be gradually increased in a cutting direction (A) so that the upper cutter (<NUM>) and the lower cutter (<NUM>) are each configured to cut the electrode sheet while widening a cutting range of the electrode sheet from one side of the cutting portion.